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PUBLIC HEALTH ASSESSMENT

PADUCAH GASEOUS DIFFUSION (USDOE)
PADUCAH, MCCRACKEN COUNTY, KENTUCKY


APPENDIX A:
DEMOGRAPHIC INFORMATION

ATSDR collects and analyzes demographic data as part of the health assessment process. We usethis information to characterize the people who live in the communities affected by the site. Areview of demographic data provides information about who lives in the community, how longpeople have lived there, and what the current population trends are. The data are generallyobtained from the U.S. Census Bureau, which conducts a nationwide census at the beginning ofevery decade. Data are available for different geographic units: county, city or town, census tract,and census block group. There are 15 census tracts in McCracken County, Kentucky [1]. Thecensus tract containing PGDP consists of five census block groups. We analyzed the data forthese different areas and looked for trends. Demographic information was also gathered duringsite visits and interviews with community members and local officials. These site visits andinterviews were especially useful in that they gave us information on population trends withinsmall geographic areas between Census dates (e.g., 1990 through 1997).

Knowing the number of children and elderly people in a community is particularly important,because these people tend to be more sensitive to environmental exposures than the generalpopulation. Similarly, knowing the average length of residence is important, since people whohave lived in the area longer may be at greater risk of exposures over longer periods of time.Occupational information lets us know if people spend most of their time working at home.Educational attainment, poverty status, and household income indicate the socioeconomic statusof the population. This gives us clues about access to health care, and subsistence fishing,hunting, or farming. Subsistence fishers, hunters, and farmers get the majority of their foodsupply from these activities and may be at greater risk for exposure to environmentalcontaminants.

This area of Kentucky is predominantly rural. However, information obtained from the CensusBureau and McCracken County Seat suggests that McCracken County's population is growing.The addition of new housing subdivisions west of Paducah City toward Ballard Countycharacterizes the bulk of the growth. There is also an ongoing initiative to bring new industriesinto the area. These changes will undoubtedly affect the make-up of the population near the site.The following is a description of demographic trends in the communities closest to PGDP.

County Demographic Data

PGDP is located in northwestern McCracken County, Kentucky, near the border of BallardCounty and across the Ohio River from Massac County, Illinois. The census data presented herecover all three counties. The analysis covers the years 1980, 1990, and 1996.

Population Data (Table A-1 [1,2])

McCracken County has the largest population of the three counties, at over 60,000, mostly due to the city of Paducah. McCracken was the only county to gain population from 1980 to 1990. Thepopulation estimates for 1996 show a population increase of 3.3% from 1990 [3]. None of thecounties are densely populated; Ballard and Massac have well under 100 persons per square mile.

All three counties have populations that are around 90% or more white. There was very littlechange in the racial or ethnic structure of the area from 1980 to 1990. The percentages of thepopulation under age 10 and age 65 or older are also similar for all three counties. There weremore elderly people than children in the three counties, which is unusual (the 1990 nationalpercentages are 14.7% under age 10 and 12.6% age 65 and older [4]) but not necessarilyuncommon for a rural area--many younger people leave for larger cities in search of bettereconomic opportunities.

Housing and Socioeconomic Data (Tables A-2 and A-3 [1,2,5,6,7])

In 1990, 20% to 25% of the residents in these three counties had lived in their current housingunits for over 20 years. In Ballard County, Kentucky, and Massac County, Illinois, 37.2% of theresidents had moved into their current housing units within the past 5 years; in McCrackenCounty, Kentucky, that percentage jumps to 46.7. (See Table A-2.)

As is typical of areas with low percentages of children, there are relatively few persons perhousehold in the three counties. (The national average is 2.63 [4], while the average for each ofthese counties is under 2.45). The vast majority of households in all three counties are owner-occupied, although there were slight increases in the percentages of renter-occupied householdsfrom 1980 to 1990. Again, this trend is typical of rural areas with static or declining populations.(See Table A-3.)

The percentage of the population age 25 and older with at least a high school education increasedby 10% to 12% for the three counties from 1980 to 1990. That increase is consistent with anational trend toward higher educational levels as the technical skills needed for most jobscontinue to become more complex. Median household income increased only modestly from1980 to 1990, and 17% to 21% of the population lived below poverty level in 1990. Betweenroughly half and over seven-tenths of employed persons in the three counties worked in "white-collar" occupations in 1990 (managerial, professional, and administrative positions, as well aspositions in the retail and service sectors). (See Table A-3.)

Most housing units in Massac and McCracken received municipal or private water. However,about half of all housing units in Ballard had water from other sources, mostly drilled wells. (SeeTable A-3.)

City or Town Demographic Data

The following is a description of the three major cities or towns near PGDP. Paducah (east ofPGDP) is the largest city in the area. The city of Metropolis and the town of Joppa are across theOhio River in Illinois.

Population Data (Table A-4 [1,2])

Paducah, Metropolis, and Joppa lost between 6% and 8% of their populations from 1980 to 1990.The vast majority of the residents in these towns are white, although in 1990 Paducah and Joppahad populations that were 20.9% and 14.2% black, respectively. There was little evidence ofchange in the racial and ethnic structure of these three towns during this 10-year period. In 1990Paducah and Metropolis had many more persons age 65 and older than persons under age 10. InJoppa the percentages were much closer, but the data suggest that all three towns will continue to"grow older" in the future.

Housing and Socioeconomic Data (Tables A-5 and A-6 [1,2,5,6,7])

In all three towns, between 20% and 30% of householders have lived in their current homes formore than 20 years. Nearly half of Paducah's householders moved into their homes between1985 and 1990, while less than 40% of the households in Joppa and Metropolis fell into thatcategory. That trend is likely due to a larger percent of renter-occupied households in Paducah(renters tend to move more frequently than do homeowners). (See Table A-5.)

As expected in places with larger elderly populations, there are relatively few persons perhousehold, especially in Metropolis and Paducah. While over 70% of Metropolis householdswere owner-occupied in 1990, Paducah and Joppa were both under 60%. Joppa declined from74.5% in 1980 to 59.2% in 1990. (See Table A-6.)

As expected, the percentages of persons with at least a high school education increasedsubstantially from 1980 to 1990. Median household income for Joppa declined in that decade,which dramatically increased the number of persons below poverty level. Poverty also increasedsomewhat in Paducah and Metropolis. (See Table A-6.)

Nearly all housing units in all three towns are served by public or private-company water sources.

Census Tracts Surrounding Paducah Gaseous Diffusion Plant

The following is a description of the census tracts that surround PGDP, an area of 5 to 10 milesof the site consisting of portions of Ballard, Massac, and McCracken counties.

Population Data (Table A-7 [1,2,8])

The area around the site gained just over 6% in total population between 1980 and 1990. No dataare available for 1996 at this level, except for the area in McCracken County. From 1990 to1996, population increased 3% in the area of McCracken County excluding the city of Paducah.Most of this increase occurred in the area near the Plant [3]. A possible reason for the growth isthe movement of people from the city of Paducah to outlying areas that fall within those tracts.There was little change in the racial make-up of the area--95% of the population is white. Aswith the counties and cities in the area, there were more elderly residents than children under age10; the gap between the two widened from 1980 to 1990.

Housing and Socioeconomic Data (Tables A-8 and A-9 [1,2,5,6,7])

In 1990, over 15% of the householders in the surrounding tracts had lived in their current housingunits for more than 30 years. Just under 40% had lived in their housing units for 5 years or less.Between 1988 and 1990 there was approximately a tenfold increase in the number of electricalpermits granted for single and mobile homes in McCracken County (excluding the city ofPaducah) [9]. Most of the growth is occurring between Paducah and the Ballard County line; thisis consistent with the idea that a number of persons may have moved from Paducah to outlyingareas. Therefore, there are substantial numbers of both long-term residents and relativenewcomers to the area. (See Table A-8.)

The number of persons per household dropped by over 7% during the 10-year period. Three-quarters of all households were owner-occupied, although there was a slight decline in thatpercentage from 1980 to 1990. There was a modest increase in the value of owner-occupiedhousing units during that period. (See Table A-9.)

Socioeconomic data were only available for 1990. In 1990, just over 70% of persons age 25 andolder had at least a high school education. About 15% of households were below poverty level.One-third of employed persons were in blue-collar occupations. (See Table A-9.)

About one-quarter of housing units got their water from drilled or dug wells or another sourceother than from a public source or private company. The Department of Energy has offered toprovide municipal water to residents of western McCracken County--in an area described inDOE's Water Policy [10]--who previously used private wells. (See Table A-9.)

Site Area

The following is a description of the immediate area containing the site: census tract 0315, blockgroup 2, in McCracken County west of the city of Paducah.

Population Data (Table A-7 [1,2,8])

The site area experienced very moderate population loss from 1980 to 1990. The block groupwas over 90% white in both censuses and changed little in racial make-up. There were slightlymore elderly persons than children under age 10 in 1990, as the percentage of children declinedand the percentage of elderly people increased slightly during that time.

Housing and Socioeconomic Data (Tables A-8 and A-9 [1,2,5,6,7])

In 1990, nearly 19% of householders had lived in their current homes for over 30 years, nearlyone-quarter had lived in their current homes for over 20 years, and over one-half had lived intheir current homes for 5 years or less. Those numbers, together with the high percentage ofowner-occupied housing units, suggests a relatively stable, non-transient population in the area;however, the population is now increasing significantly. (See Table A-8.)

Average persons per household declined substantially from 1980 to 1990, from over 2.8 to under2.6. Nearly 90% of all households were owner-occupied in both decades, which is typical ofmany rural areas. Nearly one-quarter of all households were mobile homes in 1990; there was a5% increase in mobile homes from 1980 to 1990. Median value of owner-occupied homes andmedian rent were both relatively low for both decades. However, there is evidence that thecomposition of the area may be rapidly changing. In an article in the Paducah Sun, McCrackenCounty Engineer Van Newberry cites an increase in the development of new subdivisions in thearea [11]. According to Mr. Newberry, much of the growth is occurring in western McCrackenCounty from Concord to Kevil. There were 21 new subdivisions being developed in this area,between Cairo Road-Woodville Road and U.S. 62, in 1995. The prices of homes range from$120,000 to $150,000. The values of the residential lots have increased dramatically also.Virtually all of these new homes are being provided with public water. (See Table A-9.)

Socioeconomic data for the site area were only available for 1990. Over 71% of persons age 25and older had at least a high school education. Under 13% lived below poverty level, which isrelatively low for the area. Over three-quarters of housing units in the area had water from apublic water source or private company. (See Table A-9.)


Demographic Statistics
Figure A-1. Demographic Statistics (jpg)
Demographic Statistics
Figure A-1. Demographic Statistics (pdf)


Table A-1.

County population data table
  McCracken County, Ky Ballard County, Ky Massac County, Il
   1980 1990 Change (%) 1980 1990 Change (%) 1980 1990 Change (%)
Total persons

Total area (insquare miles)

Persons persquare mile

61,310

251.14

244

62,879

251.14

250

2.6


2.5

8,798

251.2

35

7,902

251.2

31

-11.3


-11.4

14,990

239.05

63

14,752

239.05

62

-1.6


-1.6

% white

% black

% other races

89.5

9.9

0.5

89.4

10.1

0.6

-0.1

0.2

0.1

96.2

3.5

0.3

96.7

3.0

0.4

0.5

-0.5

0.1

93.5

6.1

0.3

93.6

5.9

0.6

0.1

-0.2

0.3

% under age10

% age 65 andover

14.4

14.3

13.1

16.2

-1.3

1.9

14.0

17.3

11.7

18.1

-2.3

0.8

13.9

16.9

12.6

19.3

-1.3

2.4

Sources: [1,2]


Table A-2.

Length of residence in current household, 1990: Ballard, McCracken, and Massac Counties
  Ballard Massac McCracken
Total households3,1915,90825,625
Percent householders movinginto current housing unit bytime period

1989-1990

1985-1988

1980-1984

1970-1979

1960-1969

Before 1960


14.1

23.1

12.8

24.2

11.1

14.7


13.2

24.0

14.3

20.9

12.0

15.6


19.0

27.7

12.8

20.0

9.2

11.3
Source: [5]


Table A-3.

County housing and socioeconomic data
  McCracken County, KY Ballard County, KY Massac County, IL
1980 1990
(% change)
1980 1990
(% change)
1980 1990
(% change)
Total households*

Persons/household

% households owner-occupied

23,459

2.58

71.1

25,625 (9.2)

2.41 (-6.6)

68.2 (-2.9)

3,267

2.66

85.0

3,191 (-2.3)

2.44 (-8.3)

82.3 (-2.7)

5,731

2.57

79.7

5,908 (3.1)

2.44 (-5.1)

77.6 (-2.1)

Persons 25 and older

% with at least a highschool diploma

Median income, $

% below poverty level

38,187

62.9

15,172

NA

42,531 (11.4)

73.1 (10.2)

22,606 (49.0)

17.2

5,521

53.4

12,492

NA

5,328 (-3.5)

64.2 (10.8)

19,371 (55.1)

21.0

9,449

53.1

13,144

NA

10,068 (6.6)

65.3 (12.2)

19,632 (49.4)

18.2

Employed persons 16and older

% in blue-collar jobs

% in white-collar jobs

NA

NA

NA

27,571

29.0

71.0

NA

NA

NA

3,222

45.1

54.9

NA

NA

NA

5,757

36.0

64.0

Housing units

% with water suppliedfrom a public source orprivate company

% with water suppliedfrom a drilled or dugwell or other source

28,312

89.9

10.1

27,581 (-2.6)

91.9 (2.0)

8.1 (-2.0)

3,528

51.9

48.1

3,553 (0.7)

51.1 (-0.8)

48.9 (0.8)

6,188

80.3

19.7

6,446 (4.2)

80.4 (0.1)

19.6 (-1.0)

* A household is an occupied housing unit, but the term does not include group quarters such as military barracks, prisons, andcollege dormitories.
Sources: [1,2,5,6]


Table A-4.

City or town population data table
   Paducah, KY Metropolis, IL Joppa., IL
1980 1990 Change (%) 1980 1990 Change (%) 1980 1990 Change (%)
Total persons

Total area (in square miles)

Persons per square mile

29,315

17.56

1,669

27,256

17.56

1,552

-7.0

----

-7.0

7,171

4.91

1,460

6,734

4.91

1,371

-6.1

----

-6.1

535

0.49

1,092

492

0.49

1,007

-8.0

----

-7.8

% white

% black

% other races

80.6

18.7

0.6

78.4

20.9

0.7

-2.2

2.2

0.1

92.3

7.3

0.4

91.9

7.4

0.7

-0.4

0.1

0.3

85.0

14.6

0.4

85.4

14.2

0.4

0.4

-0.4

0.0

% under age 10

% age 65 and over

13.3

19.4

13.0

22.2

-0.3

2.8

11.6

22.1

11.7

25.6

0.1

3.5

15.7

13.5

14.8

16.1

-0.9

2.6

Sources: [1,2]


Table A-5.

Length of residence in current household, 1990: cities of Paducah, Metropolis, and Joppa
  Paducah, KY Metropolis, IL Joppa, IL
Total households11,9552,889202
Percent householders moving intocurrent housing unit by time period

1989-1990

1985-1988

1980-1984

1970-1979

1960-1969

Before 1960


20.6

28.3

13.1

16.9

10.0

11.1


14.4

23.5

14.8

19.3

11.1

16.8


21.3

17.3

11.4

20.8

12.4

16.8

Source: [5]


Table A-6.

City or town housing and socioeconomic data
   Paducah, KY Metropolis, IL Joppa, IL
1980 1990 Change (%) 1980 1990 Change (%) 1980 1990 Change (%)
Total households1

Persons/household

% owner-occupied

12,050

2.37

59.2

11,955

2.21

54.4

-0.8

-6.8

-4.8

2,892

2.39

75.9

2,889

2.24

71.9

-0.1

-6.3

-4.0

204

2.62

74.5

201

2.45

59.2

-1.5

-6.5

-15.3

Persons 25 and older

Median income, $

% below poverty

19,003

11,848

18.7

19,007

17,196

24.4

0.0

45.1

5.7

4,799

11,753

15.9

4,776

16,954

17.4

-0.5

44.3

1.5

318

11,667

24.1

309

10,313

43.5

-2.8

-11.6

19.4

Employed persons 16and older

% blue-collar jobs

% white-collar jobs

NA

NA

NA

10,489

75.2

24.8

-----

-----

-----

NA

NA

NA

2,478

27.2

72.8

-----

-----

-----

NA

NA

NA

129

34.9

65.1

-----

-----

-----

Housing units

% with water supply

% with water fromdrilled or dug well

12,749

99.7

0 .3

13,150

99.8

0.2

3.1

0.1

-0.1

3,085

99.6

0 .4

3,137

99.8

0.2

1.7

0.2

-0.2

229

98.7

1.3

222

100

0.0

-3.1

1.3

-0.3

1 A household is an occupied housing unit, but the term does not include group quarters such as military barracks, prisons, and college dormitories.
Source: [1,2,5,6]


Table A-7.

Census tract population data
   Census Tracts Surrounding PGDP1 McCracken County, Census Tract 315, Block Group 2
1980 1990 Change (%) 1980 1990 Change (%)
Total persons

Total area (in square miles)

Persons per squaremile

23,733

366.13

65

25,177

366.13

69

6.1

-----

6.1

1,383

30.12

46

1,366

30.12

45

-1.2

-----

-2.2

% white

% black

% other races

94.9

4.7

0.4

95.0

4.5

0.5

0.1

-0.2

0.1

91.4

8.5

0.2

92.9

6.9

0.2

1.5

-1.6

0.0

% under age 10

% age 65 andolder

14.1

15.8

12.5

17.4

-1.6

1.6

16.1

11.5

12.4

13.0

-3.7

1.5

1 Census tracts surrounding PGDP include 9501 in Ballard County; 9701, 9702, and 9704 in Massac County;and 314 and 315 in McCracken County.
Sources: [1,2]


Table A-8.

Census tracts: length of residence in current household, 1990
(percent householders moving into current housing unit by time period)
   Census Tracts Surrounding PGDP McCracken County, Census Tract 315, Block Group 2
Total households11, 619519
Years householder movedinto current housing unit

1989-1990

1985-1988

1980-1984

1970-1979

1960-1969

Before 1960


14.5

24.9

12.9

22.1

10.4

15.2


8.1

26.5

15.3

26.1

5.3

18.7

Source: [5]


Table A-9.

Census tract housing and socioeconomic data, 1990
   Census Tracts Surrounding PGDP1 McCracken County, Census Tract 315, Block Group 2
Total households2

Persons per household

% households owner-occupied

10,008

2.47

78.7

531

2.57

88.5

Persons age 25 and older

% with at least a high school diploma

Median income, $

% below poverty level

17,105

70.1

22,630

15.2

927

71.4

27,560

12.7

Employed persons age 16 and older

% in blue collar jobs

% in white collar jobs

10,872

36.7

63.3

673

38.6

61.4

Housing units

% with water supplied from a publicsource or private company

% with water supplied from drilled ordug well or other source

10,840

75.6


24.4

580

75.7


24.3

1 Census tracts 9501 in Ballard County; 9701, 9702, and 9704 in Massac County; 314 and 315 in McCracken County.
2 A household is an occupied housing unit, but the term does not include group quarters such as military barracks, prisons, and college dormitories.
Source: [5]

References

  1. Bureau of the Census. Census of Population and Housing, 1990: Summary Tape File 1A(Illinois and Kentucky) [machine-readable data files]. Washington: US Department ofCommerce, 1991.

  2. Bureau of the Census. Census of Population and Housing, 1980: Summary Tape File 1A(Illinois and Kentucky) [machine-readable data files]. Washington: US Department ofCommerce, 1982.

  3. Bureau of the Census. County and City Data Book 1996. Washington: US Department of Commerce, 1997.

  4. Bureau of the Census. Census of Population and Housing, 1990: Summary Tape File 1C(United States) [machine-readable data files]. Washington: US Department of Commerce,1991.

  5. Bureau of the Census. Census of Population and Housing, 1990: Summary Tape File 3(Illinois and Kentucky) [machine-readable data files]. Washington: US Department ofCommerce, 1991.

  6. Bureau of the Census. Census of Population and Housing, 1980: Summary Tape File 3(Illinois and Kentucky) [machine-readable data files]. Washington: US Department ofCommerce, 1991.

  7. Bureau of the Census. Census of Housing, 1980: Characteristics of HousingUnits--Detailed Characteristics of Housing Units, Kentucky, Part 19, Vol. 1, Chapter B. Washington: US Department of Commerce, 1983.

  8. Bureau of the Census. Census of Population and Housing, 1980: Selected Areas--CensusTracts, Kentucky, Vol. 19. Washington: US Department of Commerce, 1983.

  9. Boston University. Trip Report for June 17 Through June 20, 1997.

  10. Jacobs Engineering Group, Inc. Action Memorandum for the Water Policy at the PaducahGaseous Diffusion Plant, Paducah, Kentucky. Kevil (KY): Jacobs Engineering Group,Inc; 1994 Jun. Document No. DOE/OR/06-1201&D2.

  11. Walker J. Homes in the Range. The Paducah Sun 1996 Sep 4.

APPENDIX B:
DESCRIPTION AND TABULATION OF COMMUNITY HEALTH CONCERNS

ATSDR identified community concerns about the PGDP through written correspondence,telephone conversations, informal meetings, and public availability sessions. We divided allthese concerns into five general categories, and further into sub-categories. For instance, "HealthConcerns" is a general category; one of its sub-categories is non-distinct health outcomes. Thissub-category is made up of specific outcomes--for example, headaches, dizziness, and fatigue.

To tabulate the concerns, we counted the number of times each general category was mentioned.We also counted mentions of sub-categories, and of specific components of those sub-categories.Since several people mentioned more than one general, sub-category, and specific component perconcern, there may be fewer general concerns than the combined number of specific concerns.For example: non-distinct health outcomes were mentioned eight times, but some peoplementioned more than one of the specific outcomes. Of the eight times that non-distinct outcomeswere mentioned, headaches were mentioned four times, dizziness once, aches twice, pain threetimes, nausea three times, sinus problems three times, fatigue twice, and other problems fivetimes.

General Areas of Health Concern

Cancer

Concern over cancer was mentioned the most in our correspondence and conversations withcommunity members. Some of the people were concerned about several particular types ofcancer, while others did not identify any specific type. Unspecified cancer was mentioned themost, with breast cancer second. There were nine concerns about death from cancer.

Non-Cancer

Non-cancer concerns were documented several times. As with cancer, some people mentionedmore than one type of health outcome in this category. Cardiovascular and respiratory problemswere cited the most, followed by unspecified conditions. There were two concerns over deathfrom non-cancer health conditions.

Non-Distinct

Non-distinct health concerns were also mentioned. The most common specific complaint was ofheadaches, followed by pain, nausea, and sinus problems. Most of the concerns in this categorywere non-specific, for example, "viral-like problems."

Trauma

There was one reference to trauma, which indicated that the person suffered from "burning andblisters." No more detail was given on the nature or specific cause of the problem.

General Areas of Exposure Concern

Media

The overwhelming majority of concerns involved exposure to contaminated drinking water andbreathing contaminated air. Exposure to surface water and soil/sediment was also mentioned.Concern about eating contaminated fish, game, fruits, and vegetables also was listed.

Other Issues

Other categories of concern were hazards from waste materials, waste storage (especiallydepleted uranium stored on site), transportation of waste, cleanup and treatment of contaminatedmedia, monitoring/sampling off site, and future use of this land.

General Areas of Procedural Concern

Issues

There were concerns about "procedural issues" that may or may not have been directly related tohealth concerns. The most common complaint was the "lack of trust" of the major playersinvolved at the site (Lockheed-Martin Energy Systems, Inc., and the U.S. Department of Energy).The concerns mentioned an information gap and referred to "politics" as a hindrance tocommunity members. Unreliability of data was mentioned, as well as lack of follow-up regardinga community member's specific concern.

Agency

Several agencies were mentioned under "procedural concerns." Lockheed-Martin was mentionedthe most, followed by DOE. ATSDR was also mentioned, as (though less often) was EPA. Thelocal health department was mentioned once. There were no references to the state agencies.

General Areas of Population-Level Concern

Of the people who were concerned about specific neighborhoods, the overwhelming majoritymentioned Bradford Road, describing it as an area which has a possible cancer cluster. Otherpopulations mentioned included a household, a region larger than the county, the city of Paducah,another neighborhood, and McCracken and Ballard Counties.

General Areas of Subpopulation-Level Concern

Most people who specified a subpopulation were concerned about children. People wereconcerned about pregnant/lactating women and women of childbearing age, as well as infantsand fetuses. People also expressed concern over pets, farm animals, and wildlife.


Table B-1. Community concerns

Health Concerns
Cancer
Death = 9Musculoskeletal = 2Lymphoreticular = 2Unspecified = 39
Respiratory = 1Hepatic = 0Neurological = 3Other cancer = 1
Cardiovascular = 0Renal/urinary = 0Developmental = 0Breast = 4
Gastrointestinal = 1Dermal = 0Reproductive = 0Bladder = 0
Hemopoietic = 0Ocular = 0Endocrine = 0  

Non-Cancer
Death = 2Musculoskeletal = 0Immunological = 0Physical = 0Genotoxic = 0
Respiratory = 3Hepatic = 0Neurological = 1Low birth wt. = 0Other = 3
Cardiovascular = 4Renal/urinary = 0Learning = 1Reproductive = 0Metabol. disorder = 2
Gastrointestinal = 1Dermal = 0Behavioral = 0Miscarriage = 0Endocrine = 0
Hemopoietic = 0Ocular = 0Developmental = 0Infertility = 0Lymphoreticular = 0

Non-Distinct
Headaches = 4Aches = 2Sinus = 3Body weight = 0
Dizziness = 1Pain = 3Eye irritation = 0Other = 5
Loss of appetite = 0Nausea = 3Fatigue = 2  

Trauma
Laceration = 0Concussion = 0Chemical burn = 0Other = 1
Cut = 0Other blunt trauma = 0Thermal burn = 0  

Exposure Concerns
Media
Air = 39Surface water = 20Biota = 20
Soil/sediment = 17Groundwater = 39Waste materials= 3

Other Issues
Unspecified other = 12Monitoring/sampling = 5Cleanup/treatment = 4Future land use = 1
Transp. of wastes = 1Waste storage = 4Emergency response = 0Site access = 0

Procedural Concerns
Issues
Lack of trust = 18Unreliable data = 8No response/followup= 6Don't know what they are doing = 1
Don't listen = 7Information gap = 9Politics = 9Others = 10

Agency
DOE = 21Contractors = 22State health dept. = 0Other = 2
ATSDR = 4EPA= 3Local health dept. = 1  

Population-Level Concerns
County = 1Neighborhood = 44Household = 8
City = 3Block = 2Regional/beyond county = 8

Subpopulation-Level Concerns
Men = 1Children = 5Compromised organ = 0Alcohol users = 0
Pets/farm animals = 2Women = 4Elderly = 0Altered metabolism = 0
Workers = 5Women of childbearing age = 2Cigarette smokers = 0Other = 0
Cleanup workers = 0Pregnant/lactating women = 2Low nutrition = 0On medication = 0
Wildlife = 3      

Samples of Individual Concerns

This compilation represents the range of concerns we received about PGDP. We made aconscious effort to remove any personal identifiers.

Health Concerns

Cancer

There is a possible cancer cluster in a residential community approximately two miles east of theplant (Bradford Road area).

I now have cancer, lymphoma. I would like to know if the cause is from this plant? I'm veryconcerned about the high rate of cancer in this area (Metropolis Lake Road). My husband died.He worked for Union Carbide for several years. In the past three years three other close neighborsdied of cancer also.

Are there other [cancer] hot spots other than the Bradford Road area?

I would like to ask why there is so much cancer in the neighborhood of House Road and RaglandCommunity?

I have lived on Bradford Road all my life. I have developed a lung problem during the last 24months that seemingly was caused by what I had breathed. I DON'T SMOKE!!

I am concerned about cancer and other health problems on Bradford Road:

  • Nine to ten men have lung cancer and other lung disease
  • Four women have tumors in their bodies
  • One woman has a brain tumor resulting in loss of sight in one eye and numerous other health problems

I have lived 43 of my 45 years within five miles of the plant. Also, I have worked at the plant. Iwould be interested in the results of the possible cancer cluster in the Bradford Road area as myson's dad lived there and died of cancer, and my step-father, who moved there years ago,currently has cancer.

I used to live on Bradford Road, but now live in Florida. Since the plant came to WesternKentucky, we have lost 14 people to cancer. Three, who have cancer of the breast, are still living,and several people have lung problems on Bradford Road. I lost my son and husband.

I am concerned with the amount of cancer in this area. During the eight years we lived[elsewhere], we hardly knew of anyone with cancer. Here, in western Kentucky, every family hasbeen plagued by this disease. I do think more research should be done to see what connection, ifany, there is.

Not only has Bradford Road been affected by *many cases of cancer*, you can include OgdenLanding Road, Metropolis Lake Road and Woodville Road which surround the plant.

Last, but not least, I had surgery for cancer. I believe I was directly affected by the wastematerials and releases from PGDP and their lack of concern for many years about this problem.

We do have concerns with all the plants in and around Paducah and Calvert City. We have heardthat our area has an unusually high cancer rate.

A relative retired from Union Carbide with a disability. He died from cancer and asbestosis. Oneof his doctors asked him if he had been around uranium. Check to see how many more peopledied who worked at this plant and lived nearby it.

Several of my relatives died of cancer.

Please check out the cancer rate within a ten mile radius of the plant, especially La Center,Kentucky.

At a certain point within less than a mile, we can taste a chemical, and it does affect the throat.Could this be a respiratory or cancer problem?

In Ballard County, Kentucky, there is a very large number of cancer cases, especially amongwomen--breast cancer, brain tumor, etc. A thorough study should be conducted by a privateconcern.

His father died of cancer. It is unclear which cancer ended up killing him but he suffered fromcancer of the bone, lymph, and prostate. It is unknown as to whether one of these sites hadprimary cancer which metastasized to other areas or if all these cancers originated in the affectedorgans.

He knew of breast cancer in this area but also indicated that there are some others. There are alsosome people with "respiratory problems."

In Princeton, Kentucky, there were three deaths in the same family. The father died of stomachcancer, the grandfather died of bone cancer; and people have thyroid cancer.

There are a couple of people with brain cancer. They all go to Nashville to be treated atVanderbilt. Two fellows who worked in maintenance for the plant died of cancer in their 40's.

Non-Cancer

I have been a resident of Bradford Road for several years. I'm now blind in my left eye and haveseizures and never feel good anymore.

My wife has high blood pressure and has mini strokes since 11/94. I developed a heart problem.Our medical bills have run into the hundreds of thousands of dollars, so you can't tell me Ihaven't been exposed.

What percentage of birth defects and mental retardation occurring within the region may beconsidered related to radiation exposure from contaminated air and water supplies?

This person has lived in the city of Paducah for the past 29 years. The person complained of highblood pressure and sinus problems.

This person has lived near the Plant for the past 49 years (except for two years "in the service").This person knew people with "respiratory problems."

Health Concern: respiratory problems, i.e., bronchitis, allergies, nose and throat burning whenexposed to hair spray, cigarette smoke, and raking leaves.

Health Concerns: diabetes and blood pressure problems but doesn't think it's related to the site.

Health Concerns: respiratory problems; the whole time she worked at the plant she smelledchlorine; strong colognes or hair spray causes her nose and throat to "shut down." When sheworked at the plant, she could smell the fluoride releases when they happened. She would get asore throat, her sinuses would swell, she would get headaches and allergies.

Non-Distinct

My neighbor has also been affected. The symptoms he reported to his doctor were non-specific"viral like" problems which included fatigue and headaches.

He also had various non-distinct health problems including a rash which affected other familymembers.

Workers at the plant are under a lot of stress for the following reasons:
a - they are dismissed more easily for making a honest mistake
b - the training is inadequate

A person complained of high blood pressure and sinus problems. Also, throat burning whenexposed to hair spray, cigarette smoke, and raking leaves.

Health Concerns: respiratory problems the whole time she worked at the plant and ever since.Sore throats, sometimes temperatures, and bronchitis. She would get a sore throat, her sinuseswould swell, and she would have headaches. (Most of her fellow employees complained ofheadaches and allergies.)

I have had various non-distinct health problems including a rash which affected other familymembers.

Trauma

I have been bothered by skin burning and blisters for the past five years.

Exposure Concerns

Air

Possible inhalation exposures due to past air releases of radioactive and non-radioactivecontaminants.

With TVA Fly Ash fall out--this will shorten my life by 10 years.

Possible inhalation exposures due to past air releases of radioactive and non-radioactivecontaminants due to lack of "heard warnings."

Why so much smoke from plant, especially when there are low clouds over the area?

One of my main concerns is the *present* exposures to air releases of radioactive and non-radioactive contaminants.

The air we breath is absolutely unbelievable. The odors and pollution are really bad.

What do current and past air and water quality monitoring of the region surrounding these sitesand the rivers indicate about radiation levels and pollution from other potentially harmfulchemicals?

C310 stack vented uranium, and individual is concerned that emissions are not controlled andmay be released to the environment.

Soil

They are worried about radionuclides in the soil and water. They eat a lot of food from theirgarden.

The public needs to know numbers/names of heavy metals, chemicals, radioactive substances,cubic yards of contaminated soil, etc. that are in and around the plants.

Surface Water

Possible exposure to contaminated surface water and sediments in ditches and streams.

We are concerned about toxic waste being dumped in the Little Bayou Creek and being put in thelandfill. When we complained about the smell, they said it was chicken manure and in anothercase they said the smell was caused by bovine manure.

They have a pond around their house that they use and they drink from a private drinking well.

What do current and past air and water quality monitoring of the region surrounding these sitesand the rivers indicate about radiation levels and pollution from other potentially harmfulchemicals?

Now there are lots of concern with the contamination of the rivers. He is concerned about thefeeder plant in Illinois. He wants to know the extent and the type of container breaks.

Groundwater

Past exposure to and health effects from ingestion of contaminated drinking water (Tc-99, TCE)via private wells.

Is there contaminated ground water west of plant?

I am very concerned about the contaminated drinking water. I am of the belief that groundwaterhas been monitored closely in the past and strongly hope that it will continue to be.

Why is the well water not checked around here [Kevil] for anything that could be dangerous toour health?

We have a private well that we use "daily," and we fear that we could very well be drinkingcontaminated water.

I wonder how safe our drinking water really is.

We are on well water, which was fine when we had it thoroughly tested thirty years ago by thehealth department. Since all the problems at the plant, I have had it tested numerous times, andthey said it had a high salt content. How did the salt get there after all these years? The only timeit happened was after they drilled test wells about one mile east of my house. I am sure they areputting something in those wells that made my water salty, as well as smells.

Everything travels in all directions, not just east (referring to the groundwater plume).

What are the potential health effects from drinking contaminated water or breathing air followingradioactive releases from PGDP and documented groundwater contamination?

He and his family were exposed to contaminated drinking water emanating from the site.

They are worried about wells on the other side of Metropolis being contaminated. They want toknow if Metropolis wells were monitored.

They are concerned about the size and location of the plume. They want to know if the plume isto the river or on the other side of the river.

What steps have been undertaken to protect existing underground aquifers and ground waterfrom additional contamination; how are current contamination problems being handled? Is thisprogram adequate?

Biota

Adverse health effects from consumption of contaminated fish and game from the WestKentucky Wildlife Management Area.

Adverse health effects from consumption of contaminated deer over past years.

Exposure to contaminated vegetables and fruit.

We have a garden and grow most of our food here next to the plant. I'm concerned whatcontaminants we may be exposed to from our food.

Subsistence fisherman/hunter, concerned about health effects of eating animals he catches. Hecatches and eats crappies, bluegill, some largemouth bass (but not from KOW), and buffalo carp.His wife eats raccoon once or twice/year, and rabbit and he eats squirrel once/year. He use to eatsoft shell turtles but he can't find them anymore. He eats about 6 to 7 pounds of fish/month.Location of fishing: Barkley Lake, another fish and wildlife area nearby, KOW at this site, andsometimes pond to right of main gate.

They are also concerned about plutonium in the deer.

She had been on the site to fish from time to time. She fished for several different kinds of fish atvarious places. Made at least one meal a month from the fish she caught. Locations for fishing:the game reserve; the lake north of the game reserve; lakes near Martin Marietta; north inBarkley County; and in Noah Lake, when it is not drained to be cleaned. Also, the West PaducahCoon Hunters Club and near the TVA plant. Types of fish: Crappie, *Bluegills, Bass, Buffalo,Carp (*most common). Also has cooked turtle once. If the fish is too fatty she will not clean oreat it.

She did not hunt but would eat what was given to her which included: rabbits, ground hog, squirrels, possum, raccoon and turtle. Her concerns:

  • She knew about the signs which posted mercury for bass but did not understand whysome fish were posted while others were not.
  • She also knew of people who fished to make ends meet (elderly women on Medicarewhose medicine was so expensive she fished to have enough money to eat). If they didnot eat the fish they gave it to someone else.

Waste Materials

We are especially concerned about current/future exposure to radioactive and [other]contaminants that could be released from the 100s or 1000s of barrels of waste stored on site.Those barrels cannot last forever. What can safely be done with their contents?

I believe I was directly affected by the waste materials and releases from PGDP and their lack ofconcern for many years about this problem.

Another thing that bothers me is the transportation of hazardous waste to and from the plant, andwhat we would be exposed to in case of an accident.

Other Issues

Are there more serious cumulative impacts that should be investigated and documented thatresult from multiple exposures to radionuclides and other chemicals to residents in the four-stateregion surrounding PGDP and the industrial plants?

What harm has been caused by recent releases from the PGDP?

The Paducah Gaseous Diffusion Plant has operated here since the 1950's. It and its feeder plantin Southern Illinois have created some pollution.

They are concerned about Dioxin.

He was familiar with the Site Specific Advisory Board (SSAB) and the impact of other industryon the area contributing to environmental problems.

Procedural Concerns (including Agency)

When a release was made, in the past, they used pounds or kilograms. One pound does not soundbad, but when spread in the atmosphere, one pound is a lot. Why not use cubic feet of____________ released?

My only request would be that if any releases are encountered that would affect the nearbycommunity, immediate notice be given via TV & radio.

I am of the belief that groundwater has been monitored closely in the past and strongly hope thatit will continue to be. I believe there is a need for this facility to be monitored closely.

Why is the well water not checked around here [Kevil] for anything that could be dangerous toour health?

We are on a fixed income. The Water District does not need the exorbitant amount proposed bythe Commonwealth of Kentucky Public Health Service Commission. Please don't imposeunnecessary expense on our water district. After all--you should be working to "protect" us "notpunish"!

Now they claim they are making headway in correcting these problems. Do I believe that? NO!Please LISTEN. I speak for this whole community. Talk is cheap and that's about all we've hadaround here.

I appreciate you concerns, however our complaints have fallen on deaf ears.

I have complained about my well water being ruined, but nothing is being done. They will nothook me on to city water, even though they have others very near me. If you have any power,please use it to help us out. However, I figure I have wasted my time replying to this letter, as itwill just be some more government propaganda paperwork, as has been with this environmentalgroup at the plant now. Nothing is ever accomplished.

We are on well water, which was fine when we had it thoroughly tested thirty years ago by thehealth department. Since all the problems at the plant, I have had it tested numerous times andthey said it was a high salt content. How did the salt get there after all these years? The only timeit happened was after they drilled test wells about 1 mile east of my house. I am sure they areputting something in those wells that made my water salty, as well as smells.

We are concerned about all of the health concerns affiliated with PGDP. We have eaten gamefrom the WKWMA for the past 20 years, and we feel we should be kept informed of allexposures to waste material and any and all releases from the PGDP.

Concern: Lack of trust in reports from PGDP.

On cleaning the groundwater, this is one of the biggest rip-offs I've ever seen. Take water, cleanit, and put it back in a dirty container? How stupid can people be? The company doing this is justgetting rich at the taxpayer's expense.

We were told our water would be checked in a 6 mile radius 3 to 4 years ago, and we are stillwaiting.

We have no say in what is buried in the landfill they are building--this is not right.

How can citizens gain better access to data on recent releases from the PGDP and moreimportantly, to appropriate interpretations of these data in terms of both possible short and long-term effects?

To what extent are local health departments participating in the monitoring of air and waterquality for the region surrounding these sites and the rivers? If they are not, how can citizenspressure them to become more involved with this issue?

He believes that the DOE is insensitive to the concerns of citizens affected by the site,specifically people exposed to contaminated water and workers exposed on site. He also believesthat their environmental data is unreliable, especially concerning past releases into theatmosphere.

He thinks the DOE and Lockheed Martin are insensitive to the concerns of citizens who areaffected by the contamination. He also thinks that DOE is covering up other environmentalproblems that may be ongoing.

Some complaints about Lockheed-Martin Energy Systems:

  • take their public relations with a grain of salt
  • they are wasting a lot of taxpayers money to clean up the contaminated groundwater atthe site. The "pump and treat" systems will adversely affect the Wildlife ManagementArea. They should focus on the source and stop the leaching, then worry about cleaning up the groundwater.

They were concerned about the plant increasing capacity since it was privatizing and wereworried about how the new owners would be regulated.

He is concerned with the change in ownership (of the plant).

Noticed that there is more train traffic in/out of Plant recently. Sirens are not loud enough forwhen inside house with TV playing.

Wants owner of plant to be responsive to citizens, get large volumes of a report to citizens whenit is available in the library. Make reports available on computer diskettes for citizens, libraries,and schools that have PC computers.

There is confusion among citizens on the relationships between DOE, Lockheed-Martin EnergySystems, NRC, KY Federal Facilities Oversight Unit, KY Department of Health Services,ATSDR, USEPA, etc.

With the Avlis technology imminent, the present level of each contaminant needs to be known.Then a plan needs to be formulated as to how these pollutants can be cleaned up and who willclean them up.

The public needs to know numbers/names of heavy metals, chemicals, radioactive substances,cubic yards of contaminated soil, etc. that are in and around the plants. Murray State Universityand/or Southern Illinois University could assist in the testing. Until it is known just exactly whatwe are dealing with and who created the problems, we are just jousting with windmills.

Numbers and cleanup plans are needed. Will all the pollution problems be left to our localeconomy? Or will the governing agency who created the problems be held responsible for theirwaste management?

They were familiar with the Calvert City study and thought the results were swept under the rugabout the elevated levels of acetone. They would like to see more cooperation with the Illinoisside of the community.

Need to build trust with the community--vision of non-trusted government agency. No longersubject to FOIA, ending comment period of NEPA regulations which exclude small waste sitesand transportation.

For years there was no enforcement of workers regarding wearing personal protective equipment(PPE). Since 1991, PPE has been required for the same job. The following concerns fall out ofthis:

  • why is this a hazard all of a sudden when the exact same work before required nothing?
  • what is the hazard of wearing a respirator day in and day out? These range from negative pressure respirators to SCBA (depending on the work being done)?
  • what are the dangers of wearing SCBA in the autoclave area--the temperature is very hot and symptoms are claustrophobia and sore throat?
  • do respirator cause facial disfiguration?

How much waste is stored; what happens if a container breaks?

Population-Level Concerns

Possible cancer cluster in residential community ~ 2 miles east of plant (Bradford Road area).

I'm very concerned about the high rate of cancer in this area (Metropolis Lake Road).

The cancer cluster on Bradford Road is of concern to us as well.

Possible problems of residents nearer the plant.

I would like to ask why there is so much cancer in the neighborhood of House Road and RaglandCommunity?

Why is the well water not checked around here [Kevil] for anything that could be dangerous toour health?

I and my immediate household, probably have less concern for potential health problems thanothers. Nevertheless, I would be interested in the results of the possible cancer cluster onBradford Road.

Not only has Bradford Road been affected by *many cases of cancer*, you can include OgdenLanding Road, Metropolis Lake Road and Woodville Road which surround the plant.

We do have concerns with all the plants in and around Paducah and Calvert City. We have heardthat our area has an unusually high cancer rate.

Several other neighbors and relatives, young and old . . . someone nearly every week (getscancer).

Please check out cancer rate within a ten mile radius of the plant, especially La Center, KY.

In Ballard County, KY there is a very large number of cancer cases, especially amongwomen--breast, brain tumor, etc.

How were residents downstream of PGDP affected?

How were the residents downstream from Calvert City been affected?

Other people in his neighborhood have also been affected.

Subpopulation-Level Concerns

Children

I am very concerned about past, present, and future exposures and health outcomes (cancer andnon-cancer) for my neighbors, children, and grandchildren.

What are the potential health effects on children whose parents have worked at PGDP or whohave been exposed to contaminated air and water supplies?

What percentage of birth defects and mental retardation occurring within the region may beconsidered related to radiation exposure from contaminated air and water supplies?

Workers

What health impacts may have been initiated by PGDP operations during the period 1944 to thepresent? How were workers affected? How were workers' families affected?

Is the drinking water used in the plant treated for chemical contaminants (since it comes from theOhio River)? Why do management people use bottled water? Can ATSDR have someone checkwater used for drinking on-site?

Workers are under a lot of stress for the following reasons:

  • they are dismissed more easily for making a honest mistake
  • the training is inadequate

Wildlife

I am concerned about the wildlife (especially in the game reserve). I think you should keep acloser watch on that aspect--concern about wildlife.

To what extent are animals (including fish, game, and cattle) affected by radionuclide levels inthe water and in regional plants?

Why was deer found with plutonium in the muscle?

He noticed that there are no grasshoppers, frogs, or snakes on the farm. Also, there are few birdsand other insects. The reduction in these animal and insect populations happened about 3 or 4years ago.

He never observes live or dead fish in the creek. In 1993 or 1994, over 20 deer were found deadnear Spring Bayou Church. The plant was told of the dead deer and did investigate.

Pets/Farm Animals

Cattle look older than they should. In 1994, a calf was born dead with a deformed jaw. CoffeeAnimal Clinic in LaCenter, Kentucky examined the calf; then the Plant took the calf. Presentlyhas 40 head of cattle including calves. In 60 years, there was only the one deformity.


APPENDIX C:
HEALTH GUIDELINES, COMPARISON VALUES, AND EXPOSURE FACTORS

When a hazardous substance is released to the environment, people are not always exposed to it.Exposure happens when people breathe, eat, drink, or make skin contact with a contaminant.People can also be exposed to radioactive contaminants by irradiation--if they get close to theradioactive material and if the contaminants are present at high concentrations.

Several factors determine the type and severity of health effects associated with exposure tocontaminants. Such factors include exposure concentration, frequency and duration of exposure,route of exposure, and multiplicity of exposure (i.e., the combination of contaminants androutes). Once exposure takes place, individual characteristics--such as age, sex, nutritionalstatus, genetics, lifestyle, and health status--influence how that person absorbs, distributes,metabolizes, and excretes the contaminant. These characteristics, together with the exposurefactors discussed above and the specific toxicological effects of the substance, determine thehealth effects that may result.

ATSDR considers these physical and biological characteristics when developing healthguidelines. Health guidelines provide a basis for evaluating exposures estimated fromconcentrations of contaminants in different environmental media (soil, air, water, and food)depending on the characteristics of the people who may be exposed and the length of exposure.

ATSDR reviews health and chemical information in documents called toxicological profiles.Each toxicological profile covers a particular substance; it summarizes toxicological and adversehealth effects information about that substance and includes health guidelines such as ATSDR'sminimal risk level (MRL), EPA's reference dose (RfD) and reference concentration (RfC), andEPA's cancer slope factor (CSF). ATSDR public health professionals use these guidelines todetermine a person's potential for developing adverse non-cancer health effects and/or cancerfrom exposure to a hazardous substance. ATSDR does not have guidelines for exposure toradioactive materials. Instead, the agency uses existing regulatory values and national orinternational recommendations.

An MRL is an estimate of daily human exposure to a contaminant that is likely to be without anappreciable risk of adverse non-cancer health effects over a specified duration of exposure (acute,less than 15 days; intermediate, 15 to 364 days; chronic, 365 days or more). Oral MRLs areexpressed in units of milligrams per kilogram per day (mg/kg/day); inhalation MRLs areexpressed in micrograms per cubic meter (g/m3). MRLs are not derived for dermal exposure.

RfDs and RfCs are estimates of daily human exposure, including exposure to sensitivesubpopulations, that are likely to be without appreciable risk of adverse non-cancer health effectsduring a lifetime (70 years). These guidelines are derived from experimental data and lowest-observed-adverse-effect levels (or no-observed-adverse-effect levels), adjusted downward usinguncertainty factors. The uncertainty factors are used to make the guidelines adequately protectiveof public health. RfDs and RfCs should not be viewed as strict scientific boundaries betweenwhat is toxic and what is nontoxic.

For cancer-causing substances, EPA established the CSF as a health guidance. A CSF is used todetermine the number of excess cancers expected from maximal exposure for a lifetime.

Comparison values are estimated contaminant concentrations that are unlikely to cause detectableadverse health outcomes when these concentrations occur in specific media. Comparison valuesare used to select site contaminants for further evaluation. They are based on health guidelines.Comparison values are calculated using conservative assumptions about daily intake rates by anindividual of standard body weight. Because of the conservatism of the assumptions and safetyfactors, contaminant concentrations that exceed comparison values for an environmental mediumdo not necessarily indicate a health hazard.

For nonradioactive chemicals, ATSDR uses comparison values like environmental mediaevaluation guides (EMEGs), cancer risk evaluation guides (CREGs), reference dose (orconcentration) media evaluation guides (RMEGs), and others. EMEGs, since they are derivedfrom MRLs, apply only to specific durations of exposure. Also, they depend on the amount of acontaminant ingested or inhaled. Thus, EMEGs are determined separately for children and adults,and also separately for various durations of exposure. A CREG is an estimated concentration of acontaminant that would likely cause, at most, one excess cancer in a million people exposed overa lifetime. CREGs are calculated from CSFs. Reference dose (or concentration) media evaluationguides (RMEGs) are media guides based on EPA's RfDs and RfCs.

EPA's maximum contaminant levels (MCLs) are the maximum contaminant concentration of achemical that is allowed in public drinking water systems. MCLs are regulatory standards set asclose to health goals as is feasible and are based on treatment technologies, costs, and otherfactors.

For radiological contaminants, ATSDR uses information on radiation exposure and its effectsrelated to environmental levels prepared by federal agencies, including EPA, DOE, and the USNuclear Regulatory Commission. The agency also uses other publicly available data sources andrecommendations on radiation dose limits. The National Council on Radiation Protection andMeasurements (NCRP), the International Commission on Radiological Protection (ICRP), andthe United Nations Scientific Committee on the Effects of Atomic Radiation are a few of thesources.

ATSDR uses standard or site specific intake rates for inhalation of air and ingestion of water,soil, and biota. Table C-1 presents the intake rates for groundwater, surface water, soil, andsediment that we used in estimating doses for PGDP. (The dose calculation equations, and ourassumptions about exposure factors, are derived from the ATSDR Public Health AssessmentGuidance Manual [1].) For screening purposes, ATSDR often uses the maximum contaminantconcentration detected in a specific medium at a site to identify contaminants requiring specificexposure evaluations; using the maximum concentration results in a more protective evaluation.When unknown, the biological absorption of a substance within the human body is assumed to be100%.

After estimating the potential exposure at a site, ATSDR identifies the site's "contaminants ofconcern" by comparing the exposures of interest with health guidelines, or contaminantconcentrations with comparison values. As a general rule, if the guideline or value is exceeded,ATSDR evaluates exposure to determine whether it is of potential health concern. Sometimesadditional medical and toxicological information may indicate that these exposures are not ofhealth concern. In other instances, exposures below the guidelines or values could be of healthconcern because of interactive effects with other chemicals or because of the increased sensitivityof certain individuals. Thus additional analysis is necessary to determine whether health effectsare likely to occur.

Exposure doses via ingestion are calculated on the basis of the following equation:

Dose (Ingestion) = (Chemical Conc. x IR x EF x ED) / (BW x AT)

where:

Chemical Conc. = concentration of each contaminant
IR = ingestion rate
EF = exposure frequency in days per year
ED = exposure duration in years
BW = body weight in kilograms
AT = averaging time in days

For soil and sediment doses, we take an additional step to determine exposure via dermalabsorption, with the total dose being the sum of the ingestion dose and the dermal dose.

Dose (Dermal) = (Chemical Conc. x ABS x TSA x EF x ED) / (BW x AT)

where all factors are as above except:
ABS = a chemical-specific absorption or bioavailability factor (unitless)
TSA = total soil adhered in milligrams (skin surface area x soil adherence value)

Once we have calculated the dose (in mg/kg/day) for a contaminant, we evaluate thatcontaminant's non-cancer and cancer health effects. For the former, we compare the dose withstudies that have investigated the health effects of exposure to the contaminant. For the latter, wemultiply the dose by the pathway-specific CSFs which are expressed in units of inversedose--that is, (mg/kg/day)-1.

Excess Cancer Risk = Dose (mg/kg/day) x Cancer Slope Factor (mg/kg/day)-1

The excess cancer risk is the expected increase in cancer risk due to contaminant exposure. All ofthe uncertainties and health-protective exposure assumptions associated with the dose calcuationsare included in the risk estimation, as well as the uncertainty in deriving the CSF. Excess cancerrisks are described by the following categories [2]:

No increased risk less than 1 per 100,000 < 0.00001
No apparent increased risk 1 per 100,000 0.00001
Low increased risk 1 per 10,000 0.0001
Moderate increased risk 1 per 1,000 0.001
High increased risk 1 per 100 0.01
Very high increased risk more than 1 per 100 > 0.01

None of the excess cancer risk estimates necessarily indicate that exposure to carcinogeniccontaminants will result in cancer in the exposed population.

References

  1. Agency for Toxic Substances and Disease Registry. Public Health Assessment Guidance Manual. Atlanta: US Department of Health and Human Services; 1992.

  2. Agency for Toxic Substances and Disease Registry. Public Health Decision Statement TOX.14. Draft QAA-27. Atlanta (GA): US Department of Health and Human Services; 1991 Oct 21.


Table C-1.

Dose equations and factors used in calculating exposure doses at PGDP
Dose Parameters Groundwater Surface Water Soil Sediment
Ingestion rate
WKWMA workers
Adults
Children
Pica children

2 liters/day
2 liters/day
1 liter/day
1 liter/day

0.5 liters/day
0.5 liters/day
0.5 liters/day
None

200 mg/day
50 mg/day
200 mg/day
2,000 mg/day

100 mg/day
None
100 mg/day
None
Total soil adhered (for dermal contact)
WKWMA workers
Adults
Children
Pica children


NA
NA
NA
NA


NA
NA
NA
NA


37,600 mg
9,400 mg
5,250 mg
3,000 mg


37,600 mg
9,400 mg
5,250 mg
3,000 mg
Exposure frequency
WKWMA workers
Residents (adults and children)
All groundwaterexposures basedon residentialscenario 12 days/year
12 days/year
1.5 days/week
5.6 days/week
0.75 days/week
12 days/year
Exposure area
(location of stations used to determine 67th percentile concentration)
All groundwaterexposures basedon specific welldataAll surface-water stationsoutside ofsecurity fenceWKWMA workers:buffer zone stations

Residents: stationsoutside buffer zone

All sedimentstations outsidesecurity fence
Exposure duration ~14 years
(1974-1988)
30 years (adult)
6 years (child)
30 years (adult)
6 years (child)
3 years (pica child)
30 years (adult)
6 years (child)
Body weight
Adults
Children
Pica children

70 kg
13 kg
10 kg
Averaging time
Non-cancer (exposure duration x 365 days)


Cancer


Adult: 30 years x 365 days/year
Child: 6 years x 365 days/year
Pica child: 3 years x 365 days/year

70 years x 365 days/year

This table does not include information for the food and biota pathway; see the food and biota section of thepublic health assessment.
Key: kg = kilograms; mg = milligrams; mg/day = milligrams per day; WKWMA = Western Kentucky WildlifeManagement Area



APPENDIX D:
ESTIMATION OF EXPOSURE DURATION FOR GROUNDWATER PATHWAY

Four residences near the northwest boundary of PGDP were exposed to trichloroethylene (TCE)and technetium 99, and possibly to lead, pentachlorophenol, and vinyl chloride via contaminatedgroundwater. The exposure occurred via ingestion of and dermal contact with groundwater, andinhalation of vapors from contaminated groundwater. Residents were provided with an alternatewater source upon discovery of the contaminants in August 1988.

Very little groundwater monitoring took place before 1988, so monitoring data cannot be used todetermine the duration of contaminant exposure. The rate of contaminant transport after 1988 hasbeen used to estimate the annual rate of contaminant migration. The locations of the 100-microgram-per-liter TCE isocontours were qualitatively interpreted from monitoring data for1988, 1991, and 1995. (This concentration was chosen not for health reasons but for betterreliability in the data.) These contours were interpolated using maximum annual concentrationsfrom residential and monitoring wells. The contouring procedure locates the line of equalconcentration (100 g/L) based on point values and the distances between adjacent values.

Figure D-1 shows isocontours for 1991 and 1995, which were drawn using ArcView overlaid ona site map. ArcView's map measurement tool was used to measure the plume progressions from1988 to 1991 and from 1991 to 1995. These distance measurements divided by the number ofyears of plume progression (3 years and 4 years, respectively) yield a plume progression ratebetween 125 and 330 meters per year, depending on the time interval (1988-1991, 330 metersper year; 1988-1995, 207 meters per year; 1991-1995, 125 meters per year); see Table D-1.


Table D-1.

Estimated plume migration rates based on plume locations for different time periods
Time Period Plume Progression Annual Migration Rate
1988-1991 (3 years)960 meters330 meters/year
1988-1995 (7 years)1,450 meters207 meters/year
1991-1995 (4 years)500 meters125 meters/year

The largest uncertainty associated with estimating the exposure duration is in interpreting theTCE isocontours. The 1988 contour is based on 21 annual data points (maximum values at eachwell), which are irregularly distributed. Because the data set is limited, the resulting isocontourrepresents a conservative estimate. The 1988 isocontour is approximately 1,200 meters (0.75miles) downgradient of the residential well closest to the site boundary. The small number ofdata points used to interpret the location of the 1988 plume suggests that the 1988 plume hadprogressed at least that far but probably had progressed further. Also, the time between measuredTCE concentrations was rounded to annual values. The data values used to generate the contoursare annual maximums, which occurred at approximately the same time each year.

Site personnel estimate plume migration at about 1 foot (30 centimeters) per day, which adds upto 110 meters per year. (This information came from a January 22, 1998, communication withBrad Montgomery of Bechtel Jacobs Company and a February 2, 1998, communication withRoss Miller of Geo Consultants, LLC.) This estimate is based on extensive flow modeling andthe measured migration rate of tracers injected into the Regional Gravel Aquifer (RGA). Giventhe abovementioned uncertainty about the 1988 isocontour's location, we used a contaminantmigration rate of 110 to 125 meters per year to evaluate the duration of contaminant exposure.

Table D-2 indicates the distance that the contaminant plumes have migrated beyond the affectedresidential wells. The 1991 and 1995 isocontours show that the plume has moved 2,200 meters(as of 1991) and 2,640 meters (as of 1995) downgradient of the wells. Dividing these distancesby the annual migration rate of 125 meters per year provides an estimate of the total duration ofplume migration. Subtracting the years of post-1988 migration from this total provides anestimate of the pre-1988 exposure duration. Using the 1991 and 1995 plume locations, theestimated pre-1988 exposure durations are 14.6 and 14.1 years (Table D-2). This estimate is forthose wells closest to the site boundary (RW-002 and RW-113). Exposures for wells furtherdowngradient would be of shorter duration. Also, this exposure duration is for TCEconcentrations greater than 100 g/L. Exposures at lower concentrations probably had a longer duration.


Table D-2.

Estimated exposure durations, based on 125 meters per year migration rate and distance of plume migration downgradient of residential wells
Plume Distance Beyond Residential Wells Years Migration Past 1988 Exposure Estimated Duration of Exposure (using 125 meters/year migration rate)
1988: 1,200 meters0 years9.6 years
1991: 2,200 meters3 years17.6 years - 3 years = 14.6 years
1995: 2,640 meters7 years21.1 years - 7 years = 14.1 years

TCE concentrations in the affected wells probably varied considerably over the exposure period.While there are no data for this period, well concentrations in the years after 1988 indicatesignificant variation in concentrations. (See Figure 5 in the main body of this report.) Thesevariations are probably due to the changes of seasonal water levels in the Ohio River (i.e., riverstages). Changes in the river stage directly affect both flow rate and direction in the RGA. In thecase of well RW-017, high TCE concentrations correspond with times of lower river stages.Although we used maximum annual concentrations to calculate exposure doses (Table 5 in themain body of this report), ingested concentrations probably varied by a factor of two.

TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations
Figure D-1. TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations (jpg)
TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations
Figure D-1. TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations (pdf)



APPENDIX E:
EXPOSURE TO AIRBORNE RADIONUCLIDES

Exposure doses to airborne radionuclides were estimated using the Clean Air Act AssessmentPackage--1988 (CAP88), a system developed by EPA [1,2]. CAP88 uses a modified Gaussianplume equation to estimate the average dispersion of radionuclides released from up to sixsources. The sources can be either elevated stacks, such as a smokestack, or uniform areasources, such as a pile of uranium mill tailings. Plume rise can be calculated assuming either amomentum or buoyancy-driven plume. Assessments are done for a circular grid of distances anddirections with a radius of 80 kilometers (50 miles) around the facility.

The program computes radionuclide concentrations in air, rates of deposition on ground surfaces,concentrations in food and intake rates to people from ingestion of food produced in theassessment area. Estimates of the radionuclide concentrations in produce, leafy vegetables, milk,and meat consumed by humans are made by coupling the output of the atmospheric transportmodels with the U.S. Nuclear Regulatory Commission Regulatory Guide 1.109 terrestrial foodchain models.

Dose and risk estimates from CAP88 are applicable only to low-level chronic exposures, sincethe health effects and dosimetric data are based on low-level radionuclide intakes. Thepopulation estimates used in this evaluation are the 1980 Census data provided with the CAP88model. In addition to population estimates, the model requires information on radionuclideemission rates, meteorological data, and agricultural data on consumption of locally grown foodand dairy products. Radionuclide emission data were obtained from the annual siteenvironmental monitoring reports.

The two meteorological data sets that were used in the evaluations are provided with theCAPP88 model. The 1950s emission years used 1960-1964 meteorological data; the 1996emission year evaluation used 1989-1993 meteorological data. Agricultural input data, stackparameters, and source partitioning were based on information provided in the 1996 NationalEmission Standards for Hazardous Air Pollutants (NESHAP) report [3]. Four sources account formost PGDP radionuclide emissions: the C-310 stack, C-400 combined sources, the seal and wetair exhausts, and the C-710 laboratory. CAP88 places all sources at the center of the facility withrespect to the surrounding population and varies only the height of the release. This evaluationused a zero plume rise factor based on emission temperature and velocity information in theNESHAP report.

The radionuclides evaluated include technetium 99, uranium 234, uranium 235, and uranium238. The results reported in Table E-1 are for 1956 through 1959 (the years with the largestreleases) and for 1996 (a recent year for which there is complete information). The uraniumisotope releases were partitioned between the sources in the following proportions for all years:

  • C-310 stack: 6%

  • C-400 group: 8%

  • Seal/wet air exhaust: 65%

  • C-710 laboratory: 21%

Although these proportions may have changed with process and control operations, anyvariations in the sources had minimal effect on the estimated dispersion concentrations, becauseCAP88 locates all emissions at the same geographic point and because a zero plume rise was used.


Table E-1.

Annual radionuclide emissions for selected isotopes and years [4,5,6,7]
Year Technetium 99 in curies (gigabecquerels) Uranium 234
in curies
(gigabecquerels)
Uranium 235
in curies
(gigabecquerels)
Uranium 238
in curies
(gigabecquerels)
19562.6 (96.2)1.62 (59.94)0.08 (2.96)3.50 (129.5)
19574.8 (177.6)1.10 (40.7)0.05 (1.85)1.20 (44.4)
19586.3 (233.1)1.09 (40.33)0.05 (1.85)1.16 (42.92)
19595.1 (188.7)0.93 (34.41)0.04 (1.48)1.10 (40.7)
19960.04 (1.48)0.003 (0.111)0.0001 (0.004)0.001 (0.037

In addition to the chronic or long-term process releases, accidental releases of UF6 have occurredthroughout the operating history of the PGDP facility [8,9]. The largest reported accidentalrelease occurred in 1960, when a cylinder ruptured releasing about 11,000 pounds(approximately 5,000 kilograms) of UF6 . This accident occurred in Building C-333 onNovember 17, 1960, at about 4:00 a.m. Another accidental release occurred during a fire atBuilding C-337 in December 1962. About 5,062 pounds (2,278 kilograms) of UF6 were releasedduring the fire.

Acute airborne uranium hexafluoride (UF6) concentrations near PGDP from the 1960 and 1962accidents were estimated using the RASCAL 3.0 air dispersion and dose model [10] and weatherobservations from the Paducah/Barkley Airport [11]. The RASCAL model (beta test version)provides a general assessment of potential uranium air concentrations following accidentalreleases. Due to the confluence of the water vapor from PGDP cooling towers with any airbornereleases, atmospheric humidity is assumed to be similar to conditions of light precipitation.

Our data on weather conditions at the time of the 1960 release indicate a stable to very stableatmosphere (stability class F), very low wind speed from the northwest, and a temperature of39oF (dry bulb) [11]. Under these release conditions and according to our modeling of thisaccident, an estimated uranium inhaled radiation dose of 1.5 rem (0.015 sieverts) and anestimated uranium inhaled chemical dose of 20 milligrams (mg) could have been received by themaximally exposed resident southeast of the site. The U.S. Nuclear Regulatory Commission'saction level for intake of soluble uranium is 10 mg. (At this action level, residents may beinstructed to evacuate or to stay indoors with windows closed.) A report assessing PGDPaccidents [10] indicates that a 5-mg uranium dose can produce detectable, non-permanent kidneydamage. The 1960 cylinder rupture could have resulted in inhaled exposure doses of 5 mg to 20mg to people who lived approximately 2.5 miles (4 kilometers) from the release site. Thatincludes off-site areas to the southeast of the site.

According to accident records, this release occurred on November 17, 1960, at approximately4:00 a.m. At that time of day and year, it is unlikely that nearby residents would be outside,where exposure to the maximum concentrations would occur. Air temperatures were in the 30s,so windows and doors would have been shut--very little exposure to residents inside theirhouses probably occurred. Additionally, this exposure scenario assumes that 62% of the UF6cylinder content was vented from the building over a 1-hour period and became airborne. Notesfrom accident summaries suggest that a considerable portion of the UF6 remained in the liquidphase and was recovered [9].

Estimated uranium air concentrations and doses from the 1962 fire are much lower than from the1960 cylinder accident. The explosion and fire that caused this release resulted in much greateratmospheric dispersion and much lower air concentrations and doses. Off-site uranium airconcentrations from this accident probably did not present a health hazard to the surroundingcommunity.

In addition to the documented 1960 and 1962 accidents, there were community concerns abouttwo other potential incidents: a 3-day UF6 release on March 15 through 17, 1970; and a large accidental release sometime in 1969 or 1970. A Union Carbide memorandum containedreference to a 3-day UF6 (March 15-17, 1970) that was detected via on-site air monitoring insidethe building [8]. This memorandum also indicated that the average gross alpha air monitoringresults for the perimeter east location for the period from October 1969 to May of 1970 werehigher than normal. However, the individual weekly air monitoring results indicated that thisaverage was elevated for a different time period than March 15-17, 1970 [12]. Also, the plant'soriginal report for this incident indicated that a total of 15 grams of uranium was released insidethe building and eventually released through the building ventilation system. This amount ofuranium would not have an adverse impact off site. For the second concern (an accident thatoccurred in 1969 or 1970 when houses to the southeast turned black and trees died), the siteaccident records for the 1969/70 time frame do not report any events capable of producingsignificant off-site uranium or hydrogen fluoride concentrations.

However, an extensive review of the weekly air monitoring data indicate that there were severalperiods of elevated gross alpha and gross beta (presumably, uranium and technetium 99)concentrations at perimeter air monitors during the 1969 and 1970 timeframe [12]. There is someindication that the site investigated elevated gross beta levels to the north of the plant during thistime, but there was no explanation of the cause. Due to the limited information available on thesespecific events, ATSDR cannot evaluate potential exposure doses off site. However, monitoringdata do indicate that some type of release event(s) occurred that are not reflected in the accidentreports reviewed.

At this time, it is not possible to determine if nearby residents were actually exposed tohazardous concentrations of uranium from any of these accidental releases. However, thisanalysis does estimate that potentially hazardous releases have occurred and that rupture of a UF6cylinder represents potentially hazardous conditions for residents living adjacent to PGDP. Inaddition, the air dispersion models suggest that significant concentrations of uranium may havebeen deposited in off-site areas. Currently, we have no reports of health effects related to theseaccidents; however, if data become available suggesting that health effects did occur, we will re-evaluate the need for followup activities.

References

  1. US Environmental Protection Agency. AIRDOS-EPA: A Computerized Methodology forEstimating Environmental Concentrations and Dose to Man From Airborne Releases ofRadionuclides. Washington (DC): US Environmental Protection Agency; 1979 Dec.Document No. EPA 520-1-70-009.

  2. US Environmental Protection Agency. User's Guide for CAP88-PC, Version 1.0.Washington (DC): US Environmental Protection Agency; 1992 Mar. Document No. EPA402-B-92-001.

  3. US Enrichment Corporation. United States Department of Energy Air Emissions AnnualReport (40 CFR 61, Subpart H), Calendar Year 1996, Paducah Gaseous Diffusion Plant.Paducah (KY): US Enrichment Corporation; 1997 May 23.

  4. US Department of Energy. Historical Radionuclide Releases From Current DOE OakRidge Operations Office Facilities. Oak Ridge (TN): US Department of Energy; 1988May. Document No. 707576.

  5. Baker RC, Brown EG. Environmental Monitoring Summary for the Paducah Plant for1958. Paducah (KY): US Atomic Energy Commission; 1959 May 22. Document No. KY-273.

  6. Brown, EG, Mitchell, KK. Environmental Monitoring Summary for the Paducah Plant for1959. Paducah (KY): US Atomic Energy Commission; 1960 May 31. Document No. KY-332.

  7. Lockheed Martin Energy Systems, Inc. Paducah Site Annual Environmental Report for 1996. Kevil (KY): US Department of Energy; 1997 Dec. Document No. KY/EM-206.

  8. Letter from RF Smith, Union Carbide Nuclear Division, to VG Katzel. Subject: airborne uranium contamination. June 5, 1970.

  9. Mayo T. Draft UF6 Releases at Cylinder Handling Facilities. Paducah (KY): Union Carbide Nuclear Division; Date Redacted. Document No. KY-L-863 (draft).

  10. US Nuclear Regulatory Commission. RASCAL 3.0 Beta 2, Rev. 08-18-2000. [Note: thisversion is for review and testing only, not for operational use.] Washington (DC): USNuclear Regulatory Commission; 2000.

  11. National Climatic Data Center. Surface Weather Observations for Paducah/BarkleyAirport, November 17, 1960. Asheville (NC): US Department of Commerce; 1960.

  12. Unsigned. Paducah Gaseous Diffusion Plant Environmental Monitoring Worksheets -Environmental Air Sampling (1969-1974).

APPENDIX F:
EXPOSURE TO AIRBORNE HYDROGEN FLUORIDE

During the uranium enrichment processes at PGDP, uranium hexafluoride (UF6) is released intothe air. The UF6 reacts rapidly with water in the air to form particulate uranium and fluorides, andalso hydrogen fluoride gas (HF) [1]. HF is the most abundant form of atmospheric fluoride andreacts with atmospheric water to form hydrofluoric acid aerosols. Airborne particulate fluorideshave low solubility and are removed from the atmosphere through dry and wet deposition.

Releases of UF6 (with atmospheric conversion to HF) occurred both as long-term releases due toprocess operations and as short-term releases due to accidents. Long-term (chronic) exposure toHF is evaluated based on correlation of annual UF6 releases with measured site perimeter HFconcentrations. Short-term (acute) HF exposures are evaluated using accident records and airdispersion modeling.

Estimated uranium releases and ambient air monitoring results have been reported consistentlythroughout PGDP's operational history; fluoride releases and HF ambient air concentrations havenot. Evaluation of potential HF exposures to nearby residents presents several problems: noreporting of HF release quantities or ambient air monitoring during the period of highestpotential fluoride and HF emissions (1956), changes in sampling locations, and changes in thedata reported (e.g., annual medians vs. means). Consequently, evaluation of chronic HFexposures during the period of highest potential emissions requires estimation or modeling of HFemissions from periods of consistent data reporting.

Uranium emissions are a good proxy for prediction of chronic or long-term HF ambient airconcentrations. Ambient airborne HF concentrations were measured at several locations for theyears 1961 to 1970. Comparison of mean ambient airborne HF concentrations from theselocations with uranium emission estimates for the same years provides a correlation coefficientof 0.8863, which indicates a strong positive relationship between uranium emissions andmeasured HF concentrations at the perimeter north monitoring site (HF concentrations increaseproportionately with increases in uranium emissions). That relationship is plotted in Figure F-1.

The strong correlation of uranium emissions and HF concentrations at the perimeter north stationin the years where both data sets are available allows for the prediction of HF concentrationsfrom uranium emission data in the years for which no HF monitoring data are available. TheseHF concentrations are predicted using the linear regression forecasting function in the computerprogram EXCEL (version 7.0a). Figure F-2 shows the relationships between uranium emissions(in curies per year), estimated and monitored HF concentrations at the perimeter north and onemile north stations, and measured fluoride concentrations in grass samples near the perimeternorth station.

The perimeter north station consistently had the highest concentrations of both particulateuranium and HF. The perimeter north station was closer to the fluoride processing facility thanother stations [2], and was downwind of the processing facility with respect to the prevailingsouth-southwest winds [3]. Therefore, it was assumed that this station would have had thehighest concentrations of HF during the year of highest release.

All of the measured parameters show a strong relationship to uranium emissions and to theestimated HF concentrations. Figure F-2 shows measured and estimated HF ambientconcentrations in relation to the Kentucky ambient air standard for average annual HF exposure(500 parts per billion, or ppb) [4] and the ATSDR provisional long-term guidance value of 12ppb. None of the measured or estimated HF concentrations exceed the Kentucky ambient airstandard.

ATSDR has established a provisional guidance value of 10 micrograms per liter (12 ppb) forannual average air concentrations of HF [5,6]. HF concentrations below 12 ppb (annual averagevalue) are not likely to cause adverse health effects. This guidance value is more than 100 timeslower than an exposure concentration that caused mild irritation to the eyes and noses of humanvolunteers exposed for 10 days [1]. None of the measured or estimated HF concentrations at theone north sampling station exceeded the ATSDR guidance value (Figure F-2).

Some of the estimated HF concentrations at the perimeter north station did exceed the ATSDRguidance value; the maximum value was 28 ppb (Figure F-2). The maximum annual HFemission occurred in 1956, which is the period of maximum uranium emissions. Because HFconcentrations at the perimeter north station are consistently higher than at other locations, thisstation represents a worst-case exposure scenario. It is important to point out that no off-siteresidents live at the perimeter security fence. The nearest houses are closer to the one mile northand east stations than to the perimeter stations. Consequently, the concentrations at the nearesthouse would have been closer to the concentrations estimated by the one north station (Figure F-2) than to the concentrations at the perimeter north station. The estimated annual average HFconcentrations at these points of exposure are below levels of health concern.

There is some uncertainty associated with deriving HF concentrations from uranium emissions.One measure of this uncertainty is the standard error, which is represented by error bars on thepredicted HF concentrations in Figure F-2. The error bars, which show the predicted maximumand minimum HF values, do not significantly change the predicted HF concentrations withrespect to the ATSDR and Kentucky health guidance values. Note that the largest standard errorsoccur between 1965 and 1968, the period with the highest variability and lowest uraniumemissions.

In addition to the chronic or long-term process releases, accidental releases of UF6 and HF(estimated from reported UF6 releases) have occurred throughout the operating history of thePGDP facility [7,8]. The largest reported accidental release occurred in 1960, when a cylinderruptured releasing about 11,000 pounds (approximately 5,000 kilograms) of UF6. This accidentoccurred in Building C-333 on November 17, 1960, at about 4:00 a.m. Another accidental UF6release occurred during a fire at Building C-337 in December 1962. About 5,062 pounds (2,278kilograms) of UF6 were released during this fire. Many other smaller releases have occurred, butthese were at least an order of magnitude smaller than the 1960 release and less than 30% of thesize of the 1962 release.

Airborne UF6 and HF concentrations surrounding PGDP from the 1960 and 1962 accidents wereestimated using the RASCAL 3.0 air dispersion and dose model [9] and weather observationsfrom the Paducah/Barkley Airport. The RASCAL model (beta test version) is used to provide ageneral assessment of potential HF and uranium air concentrations following accidental releases.Due to the confluence of the water vapor from PGDP cooling towers with any airborne releases,atmospheric humidity is assumed to be similar to conditions of light precipitation.

Our data on weather conditions at the time of the 1960 release indicate a stable to very stable atmosphere (stability class F), very low wind speed from the northwest, and a temperature of 39oF (dry bulb) [10]. Under these release conditions, short-term hazardous HF concentrations (6 parts per million, or ppm; 15-minute Short Term Exposure Limit) could have extended more than 1 kilometer (0.6 miles) from the release site (Building C-333) toward the southeast. This means that the estimated HF concentrations could have been at hazardous levels immediately off site. Estimated concentrations of more than 30 ppm, which is considered immediately dangerous to life/health, extended more than 500 meters (1,640 feet) from Building C-333 and would not have reached the off-site community. Table F-1 summarizes the air dispersion analysis.

According to accident records, the 1960 release occurred on November 17, 1960, atapproximately 4:00 a.m. At that time of day and year, it is unlikely that nearby residents wouldbe outside, where exposure to the maximum concentrations would occur. Air temperatures werein the 30s, so windows and doors would be shut--very little exposure to residents inside theirhouses probably occurred.

The explosion and fire that caused the 1962 release resulted in much greater atmosphericdispersion and much lower air concentrations and doses. This release was modeled using a firescenario in RASCAL 3.0, which did not analyze HF dispersion. However, HF in a fire isatmospherically unstable and very unlikely to undergo significant atmospheric dispersion. Off-site HF air concentrations from this accident probably did not present a health hazard to thesurrounding community.

In addition to the documented 1960 and 1962 accidents, there were community concerns about two other potential incidents: a 3-day UF6 release on March 15 through 17, 1970; and a large accidental release sometime in 1969 or 1970. A Union Carbide memorandum contained reference to a 3-day UF6 (March 15-17, 1970) that was detected via on-site air monitoring inside one of the buildings [7]. This memorandum also indicated that the average gross alpha air monitoring results for the perimeter east location for the period from October 1969 to May of 1970 were higher than normal. However, the individual weekly gross alpha air monitoring results indicated that this average was elevated for a different time period than March 15-17, 1970 [11]. The airborne fluoride results from the perimeter east location for March 1970 were not elevated. Also, the plant's original report for this incident indicated that a total of 15 grams of uranium was released inside the building and eventually released through the building ventilation system. This amount of uranium hexafluoride would not have an adverse impact off site. For the second concern (an accident that occurred in 1969 or 1970 when houses to the southeast turned black and trees died), the site accident records for the 1969/70 time frame do not report any events capable of producing significant off-site uranium or hydrogen fluoride concentrations.

However, an extensive review of the weekly air monitoring data indicate that there were several periods of elevated fluoride concentrations at perimeter air monitors during the 1969 and 1970 timeframe [11]. There is some indication that the site investigated elevated hydrogen fluoride levels to the east of the plant later in 1970, but there was no explanation of the cause. Due to the limited information available on these specific events, ATSDR cannot evaluate potential exposure doses off site. However, monitoring data do indicate that some type of release event(s) occurred that are not reflected in the accident reports reviewed.

At this time, it is not possible to determine if nearby residents were actually exposed to hazardous concentrations of uranium from any of these accidental releases. However, this analysis does indicate that potentially hazardous releases have occurred and that rupture of a UF6 cylinder represents potentially hazardous conditions for residents living adjacent to PGDP. Currently, we have no reports of health effects related to the reported accidents; however, if data become available suggesting that health effects did occur, we will re-evaluate the need for followup activities.

References

  1. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Fluorides, Hydrogen Fluoride, and Fluorine. Atlanta (GA): US Department of Health and Human Services; 1993.

  2. Baker RC. Environmental Monitoring Summary for the Paducah Plant for 1962 and 1963. Paducah (KY): US Atomic Energy Commission; 1964 Jul. Document No. KY-458.

  3. Lockheed Martin Energy Systems, Inc. Paducah Site Annual Environmental Report for 1996. Kevil (KY): US Department of Energy; 1997 Dec. Document No. KY/EM-206.

  4. Commonwealth of Kentucky. Ambient Air Quality Standards, 401 KAR 53:010 (1988).

  5. Agency for Toxic Substances and Disease Registry. ATSDR Record of Activity for Telephone Communication With S Chou, ATSDR Division of Toxicology. Atlanta, Georgia. October 21, 1993.

  6. Agency for Toxic Substances and Disease Registry. Health Assessment for US DOE Portsmouth Gaseous Diffusion Plant, Piketon County, Ohio. Atlanta (GA): US Department of Health and Human Services; 1996.

  7. Letter from RF Smith, Union Carbide Nuclear Division, to VG Katzel. Subject: airborne uranium contamination. June 5, 1970.

  8. Mayo T. Draft UF6 Releases at Cylinder Handling Facilities. Paducah (KY): Union Carbide Nuclear Division; Date Redacted. Document No. KY-L-863 (draft).

  9. US Nuclear Regulatory Commission. RASCAL 3.0 Beta 2, Rev. 08-18-2000. [Note: this version is for review and testing only, not for operational use.] Washington (DC): US Nuclear Regulatory Commission; 2000.

  10. National Climatic Data Center. Surface Weather Observations for Paducah/Barkley Airport, November 17, 160. Ashville (NC): US Department of Commerce; 1960.

  11. Unsigned. Paducah Gaseous Diffusion Plant Environmental Monitoring Worksheets - Environmental Air Sampling (1969-1974).


Correlation Coefficient of PGDP Uranium Emissions and Hydrogen Fluoride Measurements at the Perimeter North Station
Figure F-1. Correlation Coefficient of PGDP Uranium Emissions and Hydrogen Fluoride Measurements at the Perimeter North Station

Measured and Predicted HF Concentrations at the Perimeter North and One Mile North Sampling Stations
Figure F-2. Measured and Predicted HF Concentrations at the Perimeter North and One Mile North Sampling Stations


APPENDIX G:
AIRBORNE TRICHLOROETHYLENE DISTRIBUTION AND POTENTIAL OFF-SITE EXPOSURE

Past operations at PGDP involved large quantities of trichloroethylene (TCE) as an organicsolvent and degreaser. Although significant amounts of TCE were released into the groundwatersystem, most TCE from operational processes volatilized into the atmosphere [1]. To determineif those airborne releases present a potential for inhalation exposure to nearby residents, weconducted a TCE air dispersion analysis using the Industrial Source Complex (ISC3) model [2].

The ISC3 model uses meteorological data to generate air concentration averages, for periodsfrom 1 hour to 1 year, for any location surrounding an air emission source. ATSDR's analysisused 1989 meteorological data from the nearby Paducah Municipal Airport (Barkley Airfield).According to data available to us, the largest annual release of TCE to the atmosphere (62,826kilograms, or 138,845 pounds) occurred in 1986 [3]. The dispersion from this release wasmodeled as a single source from Building C-400--a vent 5 meters (16 feet) off the ground with adiameter of 25 centimeters (10 inches)-- and the annual release proportioned over the entireyear.

For this analysis, we assumed conservative dispersion with no chemical degradation orphotochemical breakdown of TCE. (Typically, TCE is estimated to degrade in the atmospherewith a chemical half-life of 3 to 7 days [4].) Under these conservative assumptions, themaximum airborne TCE concentration is 112 micrograms per cubic meter (g/m3) for a 1-houraveraging period, and 3 g/m3 for a 1-year averaging period, at a location 1 kilometer (0.6 miles)north of Building C-400 (that is, off site). Some animal studies have shown carcinogenic effectsfrom TCE; however, ATSDR and EPA are re-evaluating TCE's carcinogenic effects on humans.Until TCE's carcinogenicity for humans is determined, minimal risk levels (MRLs) for non-cancerous effects are used to screen for contaminants of concern. The MRL for TCE is 10,920g/m3 for acute exposures (1 to 14 days) and 546 g/m3 for intermediate exposures (15 to 365days) [4,5]. The estimated TCE air concentrations during the highest TCE release year are twoorders of magnitude lower than the MRLs and below levels of health concern. Consequently, wedid not choose TCE as a contaminant of concern for airborne releases at PGDP.

References

  1. Martin Marietta Energy Systems, Inc. Paducah Gaseous Diffusion Plant EnvironmentalReport for 1992. Paducah (KY): US Department of Energy; 1993 Sep. Document No.ES/ESH-36, KY/E-164.

  2. Trinity Consultants, Inc. Breeze Air Suite Industrial Source Complex (ISC3) DispersionModels Software Package and Users Guide, Version 1.07. Dallas (TX): TrinityConsultants, Inc.; 1996.

  3. Martin Marietta Energy Systems, Inc. Environmental Surveillance of the U.S. Departmentof Energy Paducah Reservation and Surrounding Environs During 1986. Paducah (KY):US Department of Energy; 1987 Apr. Document No. ES/ESH-1/V3.

  4. Agency for Toxic Substances and Disease Registry. Toxicological Profile forTrichloroethylene. Atlanta (GA): US Department of Health and Human Services; 1997Sep.

  5. Agency for Toxic Substances and Disease Registry. Public Health Assessment Guidance Manual. Atlanta: US Department of Health and Human Services; 1992.

APPENDIX H:
AIRBORNE HEXAVALENT CHROMIUM DISTRIBUTION FROM THE PGDP WATER COOLING TOWERS AND POTENTIAL OFF-SITE EXPOSURE

Isotopic diffusion operations at PGDP generate excess heat, which is released to the environmentthrough four cooling systems. In these systems, heat exchangers transfer heat to cooling waters,which in turn release the heat to the atmosphere through 14 water cooling towers (located in fourdiscrete areas). Until 1993, a chromium solution was added to the cooling waters to preventcorrosion [1]. This caused hexavalent chromium to be released to the atmosphere at the watercooling towers.

Although annual chromium emissions have been calculated based on the quantities of chromiumcompounds added to the cooling system, the airborne chromium concentration has never beenmeasured at on-site or off-site locations. DOE has measured and modeled chromium depositionin surrounding soils and plants, and found that chromium concentrations are at background levelsfor locations more than 1,500 meters from the cooling towers [2,3]. However, the security fenceto the east and north of the easternmost cooling systems is less than 500 meters from the towers,and the closest residence is about 1,000 meters from the towers.

Because inhalation of hexavalent chromium can be toxic, we estimated potential exposures toairborne concentrations of chromium using the ISC3 air dispersion model [4]. This model usessite-specific meteorological data (in this case, from Barkley/Paducah Municipal Airport) and aGaussian air dispersion equation to estimate contaminant concentrations.

The 1992 chromium release of 2,015 kilograms per year (0.064 grams per second, or g/sec) wasused as the emission rate for the dispersion calculations [5]. The 1992 chromium release was thehighest annual emission on record, and thus represents the most conservative source term forevaluation of public health affects. To characterize local weather, we used the most recentcomplete meteorological data set (a 1990 hourly data set) from the EPA SCRAM Web site(http://www.epa.gov/ttn/scram/) for the Barkley/Paducah Municipal Airport weather station.

The chromium emissions were modeled as four sources, based on information from the study ofcooling tower drift at PGDP [2]. Relative locations of the cooling towers were derived fromFigure 1 of that study. (See Figure 2 in the main body of this report.) Chromium concentrationsat breathing height were estimated for a 5,000-meter polar grid, with potential receptors locatedat 500-meter intervals along 16 transects (every 22.5 degrees).

The source-specific release rates and source dimensions were based on a total annual emissionrate of 0.064 g/sec, allocated between the four sources [2]. The four sources were modeled asvolume sources, with release heights of 8 meters and lateral dimensions of 25 meters (towers 1and 2) and 75 meters (towers 3 and 4). Release rates were estimated as:

  • Tower 1: 0.011 g/sec

  • Tower 2: 0.011 g/sec

  • Tower 3: 0.021 g/sec

  • Tower 4: 0.021 g/sec

The model used regulatory default options and dry settling/deposition to estimate all chromiumconcentrations [6]. Chromium particles in the cooling tower drift have diameters of 5 to 50microns. However, these particles are contained within water droplets that have diameters of 100to 1,300 microns [3]. A particle size distribution of 100 to 999 microns (with a 700-micronmean) was used in calculating settling velocities.

Maximum chromium concentrations were calculated for each potential receptor for 1-hour, 8-hour, 24-hour, and 1-year averaging periods. Because wind directions and speeds change sodrastically over a year, these maximum concentrations represent the highest estimatedconcentrations for each time period for each location. Averages for 1-hour periods aresignificantly higher than the 8-hour, 24-hour, or 1-year averages.

The results of this modeling indicate that dispersed hexavalent chromium air concentrations onsite and off site were lower than the health guidelines for intermediate and chronic exposures[7]. The intermediate minimal risk level (MRL) for inhalation of particulate hexavalentchromium is 0.5 micrograms per cubic meter (g/m3). The intermediate and chronic MRL forinhalation of dissolved hexavalent chromium as an aerosol is 0.1 g/m3. The highest estimated 1-hour, 8-hour, 24-hour, and 1-year average air concentrations were on site, between the fourcooling towers; they are listed in Table H-1. The maximum estimated off-site concentrationswere about 500 meters north-northeast of the cooling towers, outside the security fence, and arelisted below. The closest residence is approximately 1,000 meters east of the easternmost coolingsystem, and the estimated maximum concentrations for this location are listed below. The resultsof this air dispersion model are in agreement with chromium distribution studies that found noair-dispersed chromium in soil or vegetation samples beyond 1,500 meters of the cooling towers[2,3].


Table H-1.

Maximum estimated airborne hexavalent chromium concentrations
Exposure Time Maximum On Site Maximum Off Site Maximum at Closest Residence
1-hour maximum0.0215 g/m30.005 g/m30.0011 g/m3
8-hour maximum0.0108 g/m30.0025 g/m30.0005 g/m3
24-hour maximum0.0067 g/m30.0007 g/m30.0005 g/m3
1-year maximum0.0009 g/m30.0003 g/m30.0004 g/m3

The results of this modeling study, which uses conservative assumptions for settling, dispersion,and emission rates, did not find any areas where exposure to airborne chromium exceeded healthguidelines. The distribution of these airborne concentrations is supported by measurements ofdeposited chromium in soil and vegetation samples. Therefore, airborne hexavalent chromiumwas not selected as a contaminant of concern at PGDP.

References

  1. Martin Marietta Energy Systems, Inc. Paducah Gaseous Diffusion Plant Annual SiteEnvironmental Report for 1993. Paducah (KY): US Department of Energy; 1994 Oct.Document No. ES/ESH-53, KY/ERWM-18.

  2. Taylor FG, Hanna SR, Parr PD. Cooling Tower Drift Studies at the Paducah, Kentucky, Gaseous Diffusion Plant. Oak Ridge (TN): Oak Ridge National Laboratory,Environmental Sciences Division; 1978. p. 32. Document No. 1275 (ORNL/TM-6131).

  3. Taylor FG Jr. Chromated Cooling Tower Drift and the Terrestrial Environment: AReview. Nuclear Safety 1980;21(4):495-508.

  4. Trinity Consultants, Inc. Breeze Air Suite Industrial Source Complex (ISC3) Dispersion Models Software Package and Users Guide, Version 1.07. Dallas (TX): Trinity Consultants, Inc.; 1996.

  5. Martin Marietta Energy Systems, Inc. Paducah Gaseous Diffusion Plant Environmental Report for 1992. Paducah (KY): US Department of Energy; 1993 Sep. Document No. ES/ESH-36, KY/E-164.

  6. US Environmental Protection Agency. User's Guide for the Industrial Source Complex (ISC3) Dispersion Models, Volume I. Research Triangle Park (NC): US Environmental Protection Agency; 1995.

  7. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Chromium. Atlanta (GA): US Department of Health and Human Services; 1998 Aug.

APPENDIX I:
ATSDR GLOSSARY OF TERMS

Absorption:
The process of taking in, as when a sponge takes up water. Chemicals can be absorbed through the skin into the bloodstream and then transported to other organs. Chemicals can also be absorbed into the bloodstream after being breathed in or swallowed.


Activity (Radioactivity):
The number of nuclear transformations occurring in a given quantity of material per unit of time.


Acute:
Occurring over a short time, usually a few minutes or hours. An acute exposure can result in short-term or long-term health effects. An acute effect happens a short time (up to 1 year) after exposure.


Adverse Health Effect:
A change in body function or the structures of cells that can lead to disease or health problems.


Ambient:
Surrounding. For example, ambient air is usually outdoor air (as opposed to indoor air).


Analyte:
A chemical component of a sample to be determined or measured. For example, if the analyte is mercury, the laboratory test will determine the amount of mercury in the sample.


Aquifer:
A permeable rock stratum below the earth's surface through which groundwater moves; generally capable of producing water for a well.


Background Level:
A typical or average level of a chemical in the environment. Background level often refers to naturally occurring or uncontaminated levels.


Background Radiation:
Radiation resulting from cosmic rays and naturally occurring radioactive material. Background radiation is always present, and its level can change with altitude and the amount of radioactive material present in soil and building materials.


Becquerel (Bq):
The international unit of measure for the quantity of radioactive material; one becquerel is that quantity of radioactive material in which one atom decays in 1 second. One becquerel is equivalent to 27 picocuries.


Biological Uptake:
The transfer of hazardous substances from the environment to plants, animals, and humans. This can be evaluated through environmental measurements (for example, by measuring the amount of the substance in an organ known to be susceptible to that substance). More commonly, biological dose measurements are used to determine whether exposure has occurred. The presence of a contaminant, or its metabolite, in human biological specimens, such as blood, hair, or urine, is used to confirm exposure and can be an independent variable in evaluating the relationship between the exposure and any observed adverse health effects.


Biota:
The animal and plant life of a particular region. As used in ATSDR's public health assessments, biota means animals, fish, and plants that humans would eat.


Body Burden:
The total amount of a chemical in the body. Some chemicals build up in the body because they are stored in tissues (e.g., fat, bone) or are eliminated very slowly.


Cancer:
A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control.


Carcinogen:
Any substance that can cause cancer.


Carcinoma:
A malignant neoplasm composed of epithelial cells, regardless of their derivation.


Case Study:
The medical or epidemiologic evaluation of a single person or a small number of individuals to determine descriptive information about their health status or potential for exposure through interview or biomedical testing.


Central Nervous System:
The part of the nervous system that includes the brain and the spinal cord.


CERCLA:
The Comprehensive Environmental Response, Compensation, and Liability Act of 1980, also known as Superfund. CERCLA's major provisions are designed to comprehensively address the problems associated with hazardous waste sites. This is the federal legislation that created ATSDR.


Chronic:
Occurring over a long period of time (1 year or more).


Committed Equivalent Dose:
The equivalent dose to organs and tissues of reference that will be received from an intake of radioactive material by an individual over a 50-year period following the intake for adults and from age of the intake to 70 years for children.


Committed Effective Dose:
The International Commission for Radiological Protection's term for the sum of the products of (1) the weighting factors applicable to each body organ or tissue that is irradiated and (2) the committed equivalent dose to the appropriate organ or tissue integrated over time (in years) following the intake. The integrated time is 50 years for an adult and from the time of intake to 70 years for children. The committed effective dose is used in radiation safety because it implicitly includes the relative carcinogenic sensitivity of the various tissues.


Comparison Value:
The estimated contaminant concentration in a specific medium that is not likely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. Comparison values are calculated from the scientific literature available on exposure and health effects.


Concentration:
The amount of one substance dissolved or contained in a given amount of another. For example, sea water contains a higher concentration of salt than fresh water.


Contaminant:
Any substance or material unintentionally introduced into a medium (air, water, soil, sediment, food) which has the effect of rendering them toxic or otherwise harmful.


Contaminant of Concern:
Any chemical or substance that has the potential to adversely affect human receptors due to its concentration, distribution, and mode of toxicity.


Curie (Ci):
The traditional unit of measure for the quantity of radioactive material; one curie is that quantity of radioactive material in which 37 billion transformations occur per second, which is approximately the activity of 1 gram of radium. One curie is equivalent to 37 gigabecquerels.


Decay Product (Daughter Product, Progeny):
A radioisotope formed by the radioactive transformation of some other radioisotope.


Decay, Radioactive:
Transformation of the nucleus of an unstable nuclide by spontaneous emission of charged particles and/or photons.


Depleted Uranium:
Uranium in which the proportion of uranium 235 to total uranium of all isotopes is decreased from 0.72% to a lower value.


Dermal:
Referring to the skin. Dermal absorption is absorption through the skin.


Detection Limit:
The minimum concentrations that can be accurately and precisely measured by the laboratory and/or specified in a quality assurance plan.


Dose:
The amount of a substance that is absorbed or deposited in the body of an exposed organism for an increment of time. For chemicals, dose often takes body weight into account. For radioactive materials or radiation, dose denotes the quantity of radiation or energy absorbed and is a generic term for absorbed dose, equivalent dose, effective dose, committed equivalent dose, or committed effective dose.


Enriched Uranium:
Uranium in which the proportion of uranium 235 to total uranium of all isotopes is increased from 0.72% to a higher value.


Environmental Contamination:
The presence of unnatural or unintentional substances in the environment. From the public health perspective, environmental contamination should be addressed when it can affect the health and quality of life of people living and working near the contamination.


Epidemiology:
The study of the occurrence and causes of health effects in human populations. An epidemiological study often compares two groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect. The investigators try to determine if any factor is associated with the health effect.


Exposure:
Contact with a chemical by swallowing, breathing, or direct contact (such as through the skin or eyes). Exposure can be short-term (acute) or long-term (chronic).


Exposure Registry:
A system for collecting and maintaining, in a structured record, information on persons with documented environmental exposure(s). The exposure registry evolved from the need for fundamental information about the potential impact on human health of long-term exposure to low and moderate levels of hazardous substances.


Geographic Information System (GIS):
A computer hardware and software system designed to collect, manipulate, analyze, and display spatially referenced data. One can use a GIS to solve complex resource, environmental, and social problems.


Gray (Gy):
The international (SI) unit of absorbed radiation dose. One Gy equals the absorption of one joule of energy per kilogram of absorber. One gray equals 100 rad.


Hazard:
A hazard is only a source of risk if an exposure pathway exists and if exposures can have adverse consequences.


Health Outcome Data:
A major source of data for public health assessments. The identification, review, and evaluation of health outcome parameters are interactive processes involving health assessors, data source generators, and the local community. Health outcome data are community specific and may be derived from databases at the local, state, and national levels, as well as from data collected by private health care organizations and professional institutions and associations. Databases to be considered include morbidity and mortality data, birth statistics, medical records, tumor and disease registries, surveillance data, and previously conducted health studies.


Indeterminate Public Health Hazard:
A category assigned to sites or pathways for which no conclusions about public health hazard can be made because data are lacking.


Ingestion:
Swallowing (such as eating or drinking). Chemicals can get in or on food, drink, utensils, cigarettes, or hands, where they can be ingested. After ingestion, chemicals can be absorbed into the blood and distributed throughout the body.


Inhalation:
Breathing. One can be exposed to contaminants through inhalation, because inhaled contaminants can be deposited in the lungs, taken into the blood, or both.


Intermediate:
Occurring over a mid-length period of time. Intermediate exposure is exposure lasting 15 to 364 days.


Isotope:
Any nuclide of an element having the same number of protons in its nucleus (i.e., the same atomic number) as the element, but a different number of neutrons (i.e., a different mass number or atomic weight).


Media:
Soil, sediment, water, air, plants, animals, or any other parts of the environment that can contain contaminants.


Metabolism:
All the chemical reactions that enable the body to work. For example, food is metabolized (chemically changed) to supply the body with energy. Chemicals can be metabolized and made either more or less harmful by the body.


Metabolite:
Any product of metabolism.


Microcurie:
One-millionth of a curie, symbolized as Ci.


Millicurie:
One-thousandth of a curie, symbolized as mCi.


Minimal Risk Level (MRL):
An estimate of daily human exposure to a dose of radiation or a chemical that is likely to be without an appreciable risk of adverse noncancerous effects over a specified duration of exposure.


Morbidity:
Illness or disease. Morbidity rate is the number of illnesses or cases of disease in a population.


National Priorities List (NPL):
The U.S. Environmental Protection Agency's listing of sites that have undergone preliminary assessment and site inspection to determine which locations pose immediate threat to persons living or working near the release. These sites are most in need of cleanup.


No Apparent Public Health Hazard:
A category assigned to sites or pathways where human exposure to contaminated media is occurring or has occurred in the past, but is below a level of health hazard.


No Public Health Hazard:
A category assigned to sites for which data indicate no current or past exposure or no potential for exposure in the future and, therefore, no health hazard.


Picocurie:
One-trillionth of a curie, symbolized as pCi.


Plume:
An area of chemicals or radioactive materials in a particular medium, such as air or groundwater, moving away from its source in a long band or column. A plume can be a column of smoke from a chimney or contaminants moving with groundwater.


Public Health Hazard:
A category assigned to a site or pathway that poses a public health hazard because of long-term exposures to hazardous substances could result in adverse health effects.


Radiation:
The emission and propagation of energy in the form of waves. The term, when unqualified, usually refers to electromagnetic radiation, such as infrared, visible light, ultraviolet, X-ray, or gamma ray. It can also refer to corpuscular emissions, such as alpha and beta radiation.


Radioactivity:
The property of certain nuclides to spontaneously transform into other elements by emitting alpha or beta particles.


Registry:
A system for collecting and maintaining, in a structured record, information on specific persons from a defined population. Preliminary analyses and reviews are performed.


Rem:
The traditional unit of radiation equivalent dose and effective dose. The equivalent dose in rem is numerically equal to the absorbed dose in rad multiplied by a quality factor. One rem is equivalent to 0.01 sieverts (the international unit currently being used).


Risk:
In risk assessment, the probability that something will cause injury, combined with the potential severity of that injury.


Route of Exposure:
The way in which a person comes in contact with a chemical or radioactive substance. For example, drinking (ingestion) and bathing (skin contact) are two different routes of exposure to contaminants in water.


Sievert:
The international unit of radiation equivalent dose and effective dose. The equivalent dose in sieverts is numerically equal to the absorbed dose in gray multiplied by a quality factor. One sievert is equivalent to 100 rems (the traditional unit).


Specific Activity:
The total radioactivity of a given nuclide per gram of an element. This is a measure of the concentration of radioactivity. Specific activity can be expressed as Ci/gram, Bq/L, etc.


Superfund:
Another name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), which created ATSDR.


Superfund Amendments and Reauthorization Act (SARA):
The 1986 legislation that extensively amended CERCLA and broadened ATSDR's responsibilities in the areas of public health assessment, establishment and maintenance of toxicologic databases, information dissemination, and medical education.


Toxicological Profile:
A document (about a specific substance) in which ATSDR scientists interpret all known information on that substance and specify the levels at which people may be harmed if exposed to it. A toxicological profile also identifies significant data gaps in knowledge on substances and serves to initiate further research, when needed.


Urgent Public Health Hazard:
A category assigned to sites or pathways that pose a serious risk to public health as the result of short-term exposures to hazardous substances.


Vapor:
The gaseous state of a substance that, under ordinary conditions, is liquid or solid.


Volatile Organic Compounds (VOCs):
Substances containing carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen. These substances easily become vapors or gases. A significant number of the VOCs are commonly used as solvents (paint thinners, lacquer thinners, degreasers, and dry cleaning fluids).

Table of Contents

  

The largest uncertainty associated with estimating the exposure duration is in interpreting theTCE isocontours. The 1988 contour is based on 21 annual data points (maximum values at eachwell), which are irregularly distributed. Because the data set is limited, the resulting isocontourrepresents a conservative estimate. The 1988 isocontour is approximately 1,200 meters (0.75miles) downgradient of the residential well closest to the site boundary. The small number ofdata points used to interpret the location of the 1988 plume suggests that the 1988 plume hadprogressed at least that far but probably had progressed further. Also, the time between measuredTCE concentrations was rounded to annual values. The data values used to generate the contoursare annual maximums, which occurred at approximately the same time each year.

Site personnel estimate plume migration at about 1 foot (30 centimeters) per day, which adds upto 110 meters per year. (This information came from a January 22, 1998, communication withBrad Montgomery of Bechtel Jacobs Company and a February 2, 1998, communication withRoss Miller of Geo Consultants, LLC.) This estimate is based on extensive flow modeling andthe measured migration rate of tracers injected into the Regional Gravel Aquifer (RGA). Giventhe abovementioned uncertainty about the 1988 isocontour's location, we used a contaminantmigration rate of 110 to 125 meters per year to evaluate the duration of contaminant exposure.

Table D-2 indicates the distance that the contaminant plumes have migrated beyond the affectedresidential wells. The 1991 and 1995 isocontours show that the plume has moved 2,200 meters(as of 1991) and 2,640 meters (as of 1995) downgradient of the wells. Dividing these distancesby the annual migration rate of 125 meters per year provides an estimate of the total duration ofplume migration. Subtracting the years of post-1988 migration from this total provides anestimate of the pre-1988 exposure duration. Using the 1991 and 1995 plume locations, theestimated pre-1988 exposure durations are 14.6 and 14.1 years (Table D-2). This estimate is forthose wells closest to the site boundary (RW-002 and RW-113). Exposures for wells furtherdowngradient would be of shorter duration. Also, this exposure duration is for TCEconcentrations greater than 100 µg/L. Exposures at lower concentrations probably had a longer duration.


Table D-2. Estimated exposure durations, based on 125 meters per year migration rate and distance of plume migration downgradient of residential wells

Plume Distance Beyond Residential Wells Years Migration Past 1988 Exposure Estimated Duration of Exposure (using 125 meters/year migration rate)
1988: 1,200 meters0 years9.6 years
1991: 2,200 meters3 years17.6 years - 3 years = 14.6 years
1995: 2,640 meters7 years21.1 years - 7 years = 14.1 years

TCE concentrations in the affected wells probably varied considerably over the exposure period.While there are no data for this period, well concentrations in the years after 1988 indicatesignificant variation in concentrations. (See Figure 5 in the main body of this report.) Thesevariations are probably due to the changes of seasonal water levels in the Ohio River (i.e., riverstages). Changes in the river stage directly affect both flow rate and direction in the RGA. In thecase of well RW-017, high TCE concentrations correspond with times of lower river stages.Although we used maximum annual concentrations to calculate exposure doses (Table 5 in themain body of this report), ingested concentrations probably varied by a factor of two.

TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations
Figure D-1. TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations (jpg)
TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations
Figure D-1. TCE Isocontours (1991-95) and Contaminated Off-Site Well Locations (pdf)



APPENDIX E:
EXPOSURE TO AIRBORNE RADIONUCLIDES

Exposure doses to airborne radionuclides were estimated using the Clean Air Act AssessmentPackage--1988 (CAP88), a system developed by EPA [1,2]. CAP88 uses a modified Gaussianplume equation to estimate the average dispersion of radionuclides released from up to sixsources. The sources can be either elevated stacks, such as a smokestack, or uniform areasources, such as a pile of uranium mill tailings. Plume rise can be calculated assuming either amomentum or buoyancy-driven plume. Assessments are done for a circular grid of distances anddirections with a radius of 80 kilometers (50 miles) around the facility.

The program computes radionuclide concentrations in air, rates of deposition on ground surfaces,concentrations in food and intake rates to people from ingestion of food produced in theassessment area. Estimates of the radionuclide concentrations in produce, leafy vegetables, milk,and meat consumed by humans are made by coupling the output of the atmospheric transportmodels with the U.S. Nuclear Regulatory Commission Regulatory Guide 1.109 terrestrial foodchain models.

Dose and risk estimates from CAP88 are applicable only to low-level chronic exposures, sincethe health effects and dosimetric data are based on low-level radionuclide intakes. Thepopulation estimates used in this evaluation are the 1980 Census data provided with the CAP88model. In addition to population estimates, the model requires information on radionuclideemission rates, meteorological data, and agricultural data on consumption of locally grown foodand dairy products. Radionuclide emission data were obtained from the annual siteenvironmental monitoring reports.

The two meteorological data sets that were used in the evaluations are provided with theCAPP88 model. The 1950s emission years used 1960-1964 meteorological data; the 1996emission year evaluation used 1989-1993 meteorological data. Agricultural input data, stackparameters, and source partitioning were based on information provided in the 1996 NationalEmission Standards for Hazardous Air Pollutants (NESHAP) report [3]. Four sources account formost PGDP radionuclide emissions: the C-310 stack, C-400 combined sources, the seal and wetair exhausts, and the C-710 laboratory. CAP88 places all sources at the center of the facility withrespect to the surrounding population and varies only the height of the release. This evaluationused a zero plume rise factor based on emission temperature and velocity information in theNESHAP report.

The radionuclides evaluated include technetium 99, uranium 234, uranium 235, and uranium238. The results reported in Table E-1 are for 1956 through 1959 (the years with the largestreleases) and for 1996 (a recent year for which there is complete information). The uraniumisotope releases were partitioned between the sources in the following proportions for all years:

  • C-310 stack: 6%

  • C-400 group: 8%

  • Seal/wet air exhaust: 65%

  • C-710 laboratory: 21%

Although these proportions may have changed with process and control operations, anyvariations in the sources had minimal effect on the estimated dispersion concentrations, becauseCAP88 locates all emissions at the same geographic point and because a zero plume rise was used.


Table E-1. Annual radionuclide emissions for selected isotopes and years [4,5,6,7]

Year Technetium 99 in curies (gigabecquerels) Uranium 234
in curies
(gigabecquerels)
Uranium 235
in curies
(gigabecquerels)
Uranium 238
in curies
(gigabecquerels)
19562.6 (96.2)1.62 (59.94)0.08 (2.96)3.50 (129.5)
19574.8 (177.6)1.10 (40.7)0.05 (1.85)1.20 (44.4)
19586.3 (233.1)1.09 (40.33)0.05 (1.85)1.16 (42.92)
19595.1 (188.7)0.93 (34.41)0.04 (1.48)1.10 (40.7)
19960.04 (1.48)0.003 (0.111)0.0001 (0.004)0.001 (0.037

In addition to the chronic or long-term process releases, accidental releases of UF6 have occurredthroughout the operating history of the PGDP facility [8,9]. The largest reported accidentalrelease occurred in 1960, when a cylinder ruptured releasing about 11,000 pounds(approximately 5,000 kilograms) of UF6 . This accident occurred in Building C-333 onNovember 17, 1960, at about 4:00 a.m. Another accidental release occurred during a fire atBuilding C-337 in December 1962. About 5,062 pounds (2,278 kilograms) of UF6 were releasedduring the fire.

Acute airborne uranium hexafluoride (UF6) concentrations near PGDP from the 1960 and 1962accidents were estimated using the RASCAL 3.0 air dispersion and dose model [10] and weatherobservations from the Paducah/Barkley Airport [11]. The RASCAL model (beta test version)provides a general assessment of potential uranium air concentrations following accidentalreleases. Due to the confluence of the water vapor from PGDP cooling towers with any airbornereleases, atmospheric humidity is assumed to be similar to conditions of light precipitation.

Our data on weather conditions at the time of the 1960 release indicate a stable to very stableatmosphere (stability class F), very low wind speed from the northwest, and a temperature of39oF (dry bulb) [11]. Under these release conditions and according to our modeling of thisaccident, an estimated uranium inhaled radiation dose of 1.5 rem (0.015 sieverts) and anestimated uranium inhaled chemical dose of 20 milligrams (mg) could have been received by themaximally exposed resident southeast of the site. The U.S. Nuclear Regulatory Commission'saction level for intake of soluble uranium is 10 mg. (At this action level, residents may beinstructed to evacuate or to stay indoors with windows closed.) A report assessing PGDPaccidents [10] indicates that a 5-mg uranium dose can produce detectable, non-permanent kidneydamage. The 1960 cylinder rupture could have resulted in inhaled exposure doses of 5 mg to 20mg to people who lived approximately 2.5 miles (4 kilometers) from the release site. Thatincludes off-site areas to the southeast of the site.

According to accident records, this release occurred on November 17, 1960, at approximately4:00 a.m. At that time of day and year, it is unlikely that nearby residents would be outside,where exposure to the maximum concentrations would occur. Air temperatures were in the 30s,so windows and doors would have been shut--very little exposure to residents inside theirhouses probably occurred. Additionally, this exposure scenario assumes that 62% of the UF6cylinder content was vented from the building over a 1-hour period and became airborne. Notesfrom accident summaries suggest that a considerable portion of the UF6 remained in the liquidphase and was recovered [9].

Estimated uranium air concentrations and doses from the 1962 fire are much lower than from the1960 cylinder accident. The explosion and fire that caused this release resulted in much greateratmospheric dispersion and much lower air concentrations and doses. Off-site uranium airconcentrations from this accident probably did not present a health hazard to the surroundingcommunity.

In addition to the documented 1960 and 1962 accidents, there were community concerns abouttwo other potential incidents: a 3-day UF6 release on March 15 through 17, 1970; and a large accidental release sometime in 1969 or 1970. A Union Carbide memorandum containedreference to a 3-day UF6 (March 15-17, 1970) that was detected via on-site air monitoring insidethe building [8]. This memorandum also indicated that the average gross alpha air monitoringresults for the perimeter east location for the period from October 1969 to May of 1970 werehigher than normal. However, the individual weekly air monitoring results indicated that thisaverage was elevated for a different time period than March 15-17, 1970 [12]. Also, the plant'soriginal report for this incident indicated that a total of 15 grams of uranium was released insidethe building and eventually released through the building ventilation system. This amount ofuranium would not have an adverse impact off site. For the second concern (an accident thatoccurred in 1969 or 1970 when houses to the southeast turned black and trees died), the siteaccident records for the 1969/70 time frame do not report any events capable of producingsignificant off-site uranium or hydrogen fluoride concentrations.

However, an extensive review of the weekly air monitoring data indicate that there were severalperiods of elevated gross alpha and gross beta (presumably, uranium and technetium 99)concentrations at perimeter air monitors during the 1969 and 1970 timeframe [12]. There is someindication that the site investigated elevated gross beta levels to the north of the plant during thistime, but there was no explanation of the cause. Due to the limited information available on thesespecific events, ATSDR cannot evaluate potential exposure doses off site. However, monitoringdata do indicate that some type of release event(s) occurred that are not reflected in the accidentreports reviewed.

At this time, it is not possible to determine if nearby residents were actually exposed tohazardous concentrations of uranium from any of these accidental releases. However, thisanalysis does estimate that potentially hazardous releases have occurred and that rupture of a UF6cylinder represents potentially hazardous conditions for residents living adjacent to PGDP. Inaddition, the air dispersion models suggest that significant concentrations of uranium may havebeen deposited in off-site areas. Currently, we have no reports of health effects related to theseaccidents; however, if data become available suggesting that health effects did occur, we will re-evaluate the need for followup activities.

References

  1. US Environmental Protection Agency. AIRDOS-EPA: A Computerized Methodology forEstimating Environmental Concentrations and Dose to Man From Airborne Releases ofRadionuclides. Washington (DC): US Environmental Protection Agency; 1979 Dec.Document No. EPA 520-1-70-009.

  2. US Environmental Protection Agency. User's Guide for CAP88-PC, Version 1.0.Washington (DC): US Environmental Protection Agency; 1992 Mar. Document No. EPA402-B-92-001.

  3. US Enrichment Corporation. United States Department of Energy Air Emissions AnnualReport (40 CFR 61, Subpart H), Calendar Year 1996, Paducah Gaseous Diffusion Plant.Paducah (KY): US Enrichment Corporation; 1997 May 23.

  4. US Department of Energy. Historical Radionuclide Releases From Current DOE OakRidge Operations Office Facilities. Oak Ridge (TN): US Department of Energy; 1988May. Document No. 707576.

  5. Baker RC, Brown EG. Environmental Monitoring Summary for the Paducah Plant for1958. Paducah (KY): US Atomic Energy Commission; 1959 May 22. Document No. KY-273.

  6. Brown, EG, Mitchell, KK. Environmental Monitoring Summary for the Paducah Plant for1959. Paducah (KY): US Atomic Energy Commission; 1960 May 31. Document No. KY-332.

  7. Lockheed Martin Energy Systems, Inc. Paducah Site Annual Environmental Report for 1996. Kevil (KY): US Department of Energy; 1997 Dec. Document No. KY/EM-206.

  8. Letter from RF Smith, Union Carbide Nuclear Division, to VG Katzel. Subject: airborne uranium contamination. June 5, 1970.

  9. Mayo T. Draft UF6 Releases at Cylinder Handling Facilities. Paducah (KY): Union Carbide Nuclear Division; Date Redacted. Document No. KY-L-863 (draft).

  10. US Nuclear Regulatory Commission. RASCAL 3.0 Beta 2, Rev. 08-18-2000. [Note: thisversion is for review and testing only, not for operational use.] Washington (DC): USNuclear Regulatory Commission; 2000.

  11. National Climatic Data Center. Surface Weather Observations for Paducah/BarkleyAirport, November 17, 1960. Asheville (NC): US Department of Commerce; 1960.

  12. Unsigned. Paducah Gaseous Diffusion Plant Environmental Monitoring Worksheets -Environmental Air Sampling (1969-1974).

APPENDIX F:
EXPOSURE TO AIRBORNE HYDROGEN FLUORIDE

During the uranium enrichment processes at PGDP, uranium hexafluoride (UF6) is released intothe air. The UF6 reacts rapidly with water in the air to form particulate uranium and fluorides, andalso hydrogen fluoride gas (HF) [1]. HF is the most abundant form of atmospheric fluoride andreacts with atmospheric water to form hydrofluoric acid aerosols. Airborne particulate fluorideshave low solubility and are removed from the atmosphere through dry and wet deposition.

Releases of UF6 (with atmospheric conversion to HF) occurred both as long-term releases due toprocess operations and as short-term releases due to accidents. Long-term (chronic) exposure toHF is evaluated based on correlation of annual UF6 releases with measured site perimeter HFconcentrations. Short-term (acute) HF exposures are evaluated using accident records and airdispersion modeling.

Estimated uranium releases and ambient air monitoring results have been reported consistentlythroughout PGDP's operational history; fluoride releases and HF ambient air concentrations havenot. Evaluation of potential HF exposures to nearby residents presents several problems: noreporting of HF release quantities or ambient air monitoring during the period of highestpotential fluoride and HF emissions (1956), changes in sampling locations, and changes in thedata reported (e.g., annual medians vs. means). Consequently, evaluation of chronic HFexposures during the period of highest potential emissions requires estimation or modeling of HFemissions from periods of consistent data reporting.

Uranium emissions are a good proxy for prediction of chronic or long-term HF ambient airconcentrations. Ambient airborne HF concentrations were measured at several locations for theyears 1961 to 1970. Comparison of mean ambient airborne HF concentrations from theselocations with uranium emission estimates for the same years provides a correlation coefficientof 0.8863, which indicates a strong positive relationship between uranium emissions andmeasured HF concentrations at the perimeter north monitoring site (HF concentrations increaseproportionately with increases in uranium emissions). That relationship is plotted in Figure F-1.

The strong correlation of uranium emissions and HF concentrations at the perimeter north stationin the years where both data sets are available allows for the prediction of HF concentrationsfrom uranium emission data in the years for which no HF monitoring data are available. TheseHF concentrations are predicted using the linear regression forecasting function in the computerprogram EXCEL (version 7.0a). Figure F-2 shows the relationships between uranium emissions(in curies per year), estimated and monitored HF concentrations at the perimeter north and onemile north stations, and measured fluoride concentrations in grass samples near the perimeternorth station.

The perimeter north station consistently had the highest concentrations of both particulateuranium and HF. The perimeter north station was closer to the fluoride processing facility thanother stations [2], and was downwind of the processing facility with respect to the prevailingsouth-southwest winds [3]. Therefore, it was assumed that this station would have had thehighest concentrations of HF during the year of highest release.

All of the measured parameters show a strong relationship to uranium emissions and to theestimated HF concentrations. Figure F-2 shows measured and estimated HF ambientconcentrations in relation to the Kentucky ambient air standard for average annual HF exposure(500 parts per billion, or ppb) [4] and the ATSDR provisional long-term guidance value of 12ppb. None of the measured or estimated HF concentrations exceed the Kentucky ambient airstandard.

ATSDR has established a provisional guidance value of 10 micrograms per liter (12 ppb) forannual average air concentrations of HF [5,6]. HF concentrations below 12 ppb (annual averagevalue) are not likely to cause adverse health effects. This guidance value is more than 100 timeslower than an exposure concentration that caused mild irritation to the eyes and noses of humanvolunteers exposed for 10 days [1]. None of the measured or estimated HF concentrations at theone north sampling station exceeded the ATSDR guidance value (Figure F-2).

Some of the estimated HF concentrations at the perimeter north station did exceed the ATSDRguidance value; the maximum value was 28 ppb (Figure F-2). The maximum annual HFemission occurred in 1956, which is the period of maximum uranium emissions. Because HFconcentrations at the perimeter north station are consistently higher than at other locations, thisstation represents a worst-case exposure scenario. It is important to point out that no off-siteresidents live at the perimeter security fence. The nearest houses are closer to the one mile northand east stations than to the perimeter stations. Consequently, the concentrations at the nearesthouse would have been closer to the concentrations estimated by the one north station (Figure F-2) than to the concentrations at the perimeter north station. The estimated annual average HFconcentrations at these points of exposure are below levels of health concern.

There is some uncertainty associated with deriving HF concentrations from uranium emissions.One measure of this uncertainty is the standard error, which is represented by error bars on thepredicted HF concentrations in Figure F-2. The error bars, which show the predicted maximumand minimum HF values, do not significantly change the predicted HF concentrations withrespect to the ATSDR and Kentucky health guidance values. Note that the largest standard errorsoccur between 1965 and 1968, the period with the highest variability and lowest uraniumemissions.

In addition to the chronic or long-term process releases, accidental releases of UF6 and HF(estimated from reported UF6 releases) have occurred throughout the operating history of thePGDP facility [7,8]. The largest reported accidental release occurred in 1960, when a cylinderruptured releasing about 11,000 pounds (approximately 5,000 kilograms) of UF6. This accidentoccurred in Building C-333 on November 17, 1960, at about 4:00 a.m. Another accidental UF6release occurred during a fire at Building C-337 in December 1962. About 5,062 pounds (2,278kilograms) of UF6 were released during this fire. Many other smaller releases have occurred, butthese were at least an order of magnitude smaller than the 1960 release and less than 30% of thesize of the 1962 release.

Airborne UF6 and HF concentrations surrounding PGDP from the 1960 and 1962 accidents wereestimated using the RASCAL 3.0 air dispersion and dose model [9] and weather observationsfrom the Paducah/Barkley Airport. The RASCAL model (beta test version) is used to provide ageneral assessment of potential HF and uranium air concentrations following accidental releases.Due to the confluence of the water vapor from PGDP cooling towers with any airborne releases,atmospheric humidity is assumed to be similar to conditions of light precipitation.

Our data on weather conditions at the time of the 1960 release indicate a stable to very stable atmosphere (stability class F), very low wind speed from the northwest, and a temperature of 39oF (dry bulb) [10]. Under these release conditions, short-term hazardous HF concentrations (6 parts per million, or ppm; 15-minute Short Term Exposure Limit) could have extended more than 1 kilometer (0.6 miles) from the release site (Building C-333) toward the southeast. This means that the estimated HF concentrations could have been at hazardous levels immediately off site. Estimated concentrations of more than 30 ppm, which is considered immediately dangerous to life/health, extended more than 500 meters (1,640 feet) from Building C-333 and would not have reached the off-site community. Table F-1 summarizes the air dispersion analysis.

According to accident records, the 1960 release occurred on November 17, 1960, atapproximately 4:00 a.m. At that time of day and year, it is unlikely that nearby residents wouldbe outside, where exposure to the maximum concentrations would occur. Air temperatures werein the 30s, so windows and doors would be shut--very little exposure to residents inside theirhouses probably occurred.

The explosion and fire that caused the 1962 release resulted in much greater atmosphericdispersion and much lower air concentrations and doses. This release was modeled using a firescenario in RASCAL 3.0, which did not analyze HF dispersion. However, HF in a fire isatmospherically unstable and very unlikely to undergo significant atmospheric dispersion. Off-site HF air concentrations from this accident probably did not present a health hazard to thesurrounding community.

In addition to the documented 1960 and 1962 accidents, there were community concerns about two other potential incidents: a 3-day UF6 release on March 15 through 17, 1970; and a large accidental release sometime in 1969 or 1970. A Union Carbide memorandum contained reference to a 3-day UF6 (March 15-17, 1970) that was detected via on-site air monitoring inside one of the buildings [7]. This memorandum also indicated that the average gross alpha air monitoring results for the perimeter east location for the period from October 1969 to May of 1970 were higher than normal. However, the individual weekly gross alpha air monitoring results indicated that this average was elevated for a different time period than March 15-17, 1970 [11]. The airborne fluoride results from the perimeter east location for March 1970 were not elevated. Also, the plant's original report for this incident indicated that a total of 15 grams of uranium was released inside the building and eventually released through the building ventilation system. This amount of uranium hexafluoride would not have an adverse impact off site. For the second concern (an accident that occurred in 1969 or 1970 when houses to the southeast turned black and trees died), the site accident records for the 1969/70 time frame do not report any events capable of producing significant off-site uranium or hydrogen fluoride concentrations.

However, an extensive review of the weekly air monitoring data indicate that there were several periods of elevated fluoride concentrations at perimeter air monitors during the 1969 and 1970 timeframe [11]. There is some indication that the site investigated elevated hydrogen fluoride levels to the east of the plant later in 1970, but there was no explanation of the cause. Due to the limited information available on these specific events, ATSDR cannot evaluate potential exposure doses off site. However, monitoring data do indicate that some type of release event(s) occurred that are not reflected in the accident reports reviewed.

At this time, it is not possible to determine if nearby residents were actually exposed to hazardous concentrations of uranium from any of these accidental releases. However, this analysis does indicate that potentially hazardous releases have occurred and that rupture of a UF6 cylinder represents potentially hazardous conditions for residents living adjacent to PGDP. Currently, we have no reports of health effects related to the reported accidents; however, if data become available suggesting that health effects did occur, we will re-evaluate the need for followup activities.

References

  1. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Fluorides, Hydrogen Fluoride, and Fluorine. Atlanta (GA): US Department of Health and Human Services; 1993.

  2. Baker RC. Environmental Monitoring Summary for the Paducah Plant for 1962 and 1963. Paducah (KY): US Atomic Energy Commission; 1964 Jul. Document No. KY-458.

  3. Lockheed Martin Energy Systems, Inc. Paducah Site Annual Environmental Report for 1996. Kevil (KY): US Department of Energy; 1997 Dec. Document No. KY/EM-206.

  4. Commonwealth of Kentucky. Ambient Air Quality Standards, 401 KAR 53:010 (1988).

  5. Agency for Toxic Substances and Disease Registry. ATSDR Record of Activity for Telephone Communication With S Chou, ATSDR Division of Toxicology. Atlanta, Georgia. October 21, 1993.

  6. Agency for Toxic Substances and Disease Registry. Health Assessment for US DOE Portsmouth Gaseous Diffusion Plant, Piketon County, Ohio. Atlanta (GA): US Department of Health and Human Services; 1996.

  7. Letter from RF Smith, Union Carbide Nuclear Division, to VG Katzel. Subject: airborne uranium contamination. June 5, 1970.

  8. Mayo T. Draft UF6 Releases at Cylinder Handling Facilities. Paducah (KY): Union Carbide Nuclear Division; Date Redacted. Document No. KY-L-863 (draft).

  9. US Nuclear Regulatory Commission. RASCAL 3.0 Beta 2, Rev. 08-18-2000. [Note: this version is for review and testing only, not for operational use.] Washington (DC): US Nuclear Regulatory Commission; 2000.

  10. National Climatic Data Center. Surface Weather Observations for Paducah/Barkley Airport, November 17, 160. Ashville (NC): US Department of Commerce; 1960.

  11. Unsigned. Paducah Gaseous Diffusion Plant Environmental Monitoring Worksheets - Environmental Air Sampling (1969-1974).


Correlation Coefficient of PGDP Uranium Emissions and Hydrogen Fluoride Measurements at the Perimeter North Station
Figure F-1. Correlation Coefficient of PGDP Uranium Emissions and Hydrogen Fluoride Measurements at the Perimeter North Station

Measured and Predicted HF Concentrations at the Perimeter North and One Mile North Sampling Stations
Figure F-2. Measured and Predicted HF Concentrations at the Perimeter North and One Mile North Sampling Stations


APPENDIX G:
AIRBORNE TRICHLOROETHYLENE DISTRIBUTION AND POTENTIAL OFF-SITE EXPOSURE

Past operations at PGDP involved large quantities of trichloroethylene (TCE) as an organicsolvent and degreaser. Although significant amounts of TCE were released into the groundwatersystem, most TCE from operational processes volatilized into the atmosphere [1]. To determineif those airborne releases present a potential for inhalation exposure to nearby residents, weconducted a TCE air dispersion analysis using the Industrial Source Complex (ISC3) model [2].

The ISC3 model uses meteorological data to generate air concentration averages, for periodsfrom 1 hour to 1 year, for any location surrounding an air emission source. ATSDR's analysisused 1989 meteorological data from the nearby Paducah Municipal Airport (Barkley Airfield).According to data available to us, the largest annual release of TCE to the atmosphere (62,826kilograms, or 138,845 pounds) occurred in 1986 [3]. The dispersion from this release wasmodeled as a single source from Building C-400--a vent 5 meters (16 feet) off the ground with adiameter of 25 centimeters (10 inches)-- and the annual release proportioned over the entireyear.

For this analysis, we assumed conservative dispersion with no chemical degradation orphotochemical breakdown of TCE. (Typically, TCE is estimated to degrade in the atmospherewith a chemical half-life of 3 to 7 days [4].) Under these conservative assumptions, themaximum airborne TCE concentration is 112 micrograms per cubic meter (µg/m3) for a 1-houraveraging period, and 3 µg/m3 for a 1-year averaging period, at a location 1 kilometer (0.6 miles)north of Building C-400 (that is, off site). Some animal studies have shown carcinogenic effectsfrom TCE; however, ATSDR and EPA are re-evaluating TCE's carcinogenic effects on humans.Until TCE's carcinogenicity for humans is determined, minimal risk levels (MRLs) for non-cancerous effects are used to screen for contaminants of concern. The MRL for TCE is 10,920µg/m3 for acute exposures (1 to 14 days) and 546 µg/m3 for intermediate exposures (15 to 365days) [4,5]. The estimated TCE air concentrations during the highest TCE release year are twoorders of magnitude lower than the MRLs and below levels of health concern. Consequently, wedid not choose TCE as a contaminant of concern for airborne releases at PGDP.

References

  1. Martin Marietta Energy Systems, Inc. Paducah Gaseous Diffusion Plant EnvironmentalReport for 1992. Paducah (KY): US Department of Energy; 1993 Sep. Document No.ES/ESH-36, KY/E-164.

  2. Trinity Consultants, Inc. Breeze Air Suite Industrial Source Complex (ISC3) DispersionModels Software Package and Users Guide, Version 1.07. Dallas (TX): TrinityConsultants, Inc.; 1996.

  3. Martin Marietta Energy Systems, Inc. Environmental Surveillance of the U.S. Departmentof Energy Paducah Reservation and Surrounding Environs During 1986. Paducah (KY):US Department of Energy; 1987 Apr. Document No. ES/ESH-1/V3.

  4. Agency for Toxic Substances and Disease Registry. Toxicological Profile forTrichloroethylene. Atlanta (GA): US Department of Health and Human Services; 1997Sep.

  5. Agency for Toxic Substances and Disease Registry. Public Health Assessment Guidance Manual. Atlanta: US Department of Health and Human Services; 1992.

APPENDIX H:
AIRBORNE HEXAVALENT CHROMIUM DISTRIBUTION FROM THE PGDP WATER COOLING TOWERS AND POTENTIAL OFF-SITE EXPOSURE

Isotopic diffusion operations at PGDP generate excess heat, which is released to the environmentthrough four cooling systems. In these systems, heat exchangers transfer heat to cooling waters,which in turn release the heat to the atmosphere through 14 water cooling towers (located in fourdiscrete areas). Until 1993, a chromium solution was added to the cooling waters to preventcorrosion [1]. This caused hexavalent chromium to be released to the atmosphere at the watercooling towers.

Although annual chromium emissions have been calculated based on the quantities of chromiumcompounds added to the cooling system, the airborne chromium concentration has never beenmeasured at on-site or off-site locations. DOE has measured and modeled chromium depositionin surrounding soils and plants, and found that chromium concentrations are at background levelsfor locations more than 1,500 meters from the cooling towers [2,3]. However, the security fenceto the east and north of the easternmost cooling systems is less than 500 meters from the towers,and the closest residence is about 1,000 meters from the towers.

Because inhalation of hexavalent chromium can be toxic, we estimated potential exposures toairborne concentrations of chromium using the ISC3 air dispersion model [4]. This model usessite-specific meteorological data (in this case, from Barkley/Paducah Municipal Airport) and aGaussian air dispersion equation to estimate contaminant concentrations.

The 1992 chromium release of 2,015 kilograms per year (0.064 grams per second, or g/sec) wasused as the emission rate for the dispersion calculations [5]. The 1992 chromium release was thehighest annual emission on record, and thus represents the most conservative source term forevaluation of public health affects. To characterize local weather, we used the most recentcomplete meteorological data set (a 1990 hourly data set) from the EPA SCRAM Web site(http://www.epa.gov/ttn/scram/) for the Barkley/Paducah Municipal Airport weather station.

The chromium emissions were modeled as four sources, based on information from the study ofcooling tower drift at PGDP [2]. Relative locations of the cooling towers were derived fromFigure 1 of that study. (See Figure 2 in the main body of this report.) Chromium concentrationsat breathing height were estimated for a 5,000-meter polar grid, with potential receptors locatedat 500-meter intervals along 16 transects (every 22.5 degrees).

The source-specific release rates and source dimensions were based on a total annual emissionrate of 0.064 g/sec, allocated between the four sources [2]. The four sources were modeled asvolume sources, with release heights of 8 meters and lateral dimensions of 25 meters (towers 1and 2) and 75 meters (towers 3 and 4). Release rates were estimated as:

  • Tower 1: 0.011 g/sec

  • Tower 2: 0.011 g/sec

  • Tower 3: 0.021 g/sec

  • Tower 4: 0.021 g/sec

The model used regulatory default options and dry settling/deposition to estimate all chromiumconcentrations [6]. Chromium particles in the cooling tower drift have diameters of 5 to 50microns. However, these particles are contained within water droplets that have diameters of 100to 1,300 microns [3]. A particle size distribution of 100 to 999 microns (with a 700-micronmean) was used in calculating settling velocities.

Maximum chromium concentrations were calculated for each potential receptor for 1-hour, 8-hour, 24-hour, and 1-year averaging periods. Because wind directions and speeds change sodrastically over a year, these maximum concentrations represent the highest estimatedconcentrations for each time period for each location. Averages for 1-hour periods aresignificantly higher than the 8-hour, 24-hour, or 1-year averages.

The results of this modeling indicate that dispersed hexavalent chromium air concentrations onsite and off site were lower than the health guidelines for intermediate and chronic exposures[7]. The intermediate minimal risk level (MRL) for inhalation of particulate hexavalentchromium is 0.5 micrograms per cubic meter (µg/m3). The intermediate and chronic MRL forinhalation of dissolved hexavalent chromium as an aerosol is 0.1 µg/m3. The highest estimated 1-hour, 8-hour, 24-hour, and 1-year average air concentrations were on site, between the fourcooling towers; they are listed in Table H-1. The maximum estimated off-site concentrationswere about 500 meters north-northeast of the cooling towers, outside the security fence, and arelisted below. The closest residence is approximately 1,000 meters east of the easternmost coolingsystem, and the estimated maximum concentrations for this location are listed below. The resultsof this air dispersion model are in agreement with chromium distribution studies that found noair-dispersed chromium in soil or vegetation samples beyond 1,500 meters of the cooling towers[2,3].


Table H-1. Maximum estimated airborne hexavalent chromium concentrations

Exposure Time Maximum On Site Maximum Off Site Maximum at Closest Residence
1-hour maximum0.0215 µg/m30.005 µg/m30.0011 µg/m3
8-hour maximum0.0108 µg/m30.0025 µg/m30.0005 µg/m3
24-hour maximum0.0067 µg/m30.0007 µg/m30.0005 µg/m3
1-year maximum0.0009 µg/m30.0003 µg/m30.0004 µg/m3

The results of this modeling study, which uses conservative assumptions for settling, dispersion,and emission rates, did not find any areas where exposure to airborne chromium exceeded healthguidelines. The distribution of these airborne concentrations is supported by measurements ofdeposited chromium in soil and vegetation samples. Therefore, airborne hexavalent chromiumwas not selected as a contaminant of concern at PGDP.

References

  1. Martin Marietta Energy Systems, Inc. Paducah Gaseous Diffusion Plant Annual SiteEnvironmental Report for 1993. Paducah (KY): US Department of Energy; 1994 Oct.Document No. ES/ESH-53, KY/ERWM-18.

  2. Taylor FG, Hanna SR, Parr PD. Cooling Tower Drift Studies at the Paducah, Kentucky, Gaseous Diffusion Plant. Oak Ridge (TN): Oak Ridge National Laboratory,Environmental Sciences Division; 1978. p. 32. Document No. 1275 (ORNL/TM-6131).

  3. Taylor FG Jr. Chromated Cooling Tower Drift and the Terrestrial Environment: AReview. Nuclear Safety 1980;21(4):495-508.

  4. Trinity Consultants, Inc. Breeze Air Suite Industrial Source Complex (ISC3) Dispersion Models Software Package and Users Guide, Version 1.07. Dallas (TX): Trinity Consultants, Inc.; 1996.

  5. Martin Marietta Energy Systems, Inc. Paducah Gaseous Diffusion Plant Environmental Report for 1992. Paducah (KY): US Department of Energy; 1993 Sep. Document No. ES/ESH-36, KY/E-164.

  6. US Environmental Protection Agency. User's Guide for the Industrial Source Complex (ISC3) Dispersion Models, Volume I. Research Triangle Park (NC): US Environmental Protection Agency; 1995.

  7. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Chromium. Atlanta (GA): US Department of Health and Human Services; 1998 Aug.

APPENDIX I:
ATSDR GLOSSARY OF TERMS

Absorption:
The process of taking in, as when a sponge takes up water. Chemicals can be absorbed through the skin into the bloodstream and then transported to other organs. Chemicals can also be absorbed into the bloodstream after being breathed in or swallowed.


Activity (Radioactivity):
The number of nuclear transformations occurring in a given quantity of material per unit of time.


Acute:
Occurring over a short time, usually a few minutes or hours. An acute exposure can result in short-term or long-term health effects. An acute effect happens a short time (up to 1 year) after exposure.


Adverse Health Effect:
A change in body function or the structures of cells that can lead to disease or health problems.


Ambient:
Surrounding. For example, ambient air is usually outdoor air (as opposed to indoor air).


Analyte:
A chemical component of a sample to be determined or measured. For example, if the analyte is mercury, the laboratory test will determine the amount of mercury in the sample.


Aquifer:
A permeable rock stratum below the earth's surface through which groundwater moves; generally capable of producing water for a well.


Background Level:
A typical or average level of a chemical in the environment. Background level often refers to naturally occurring or uncontaminated levels.


Background Radiation:
Radiation resulting from cosmic rays and naturally occurring radioactive material. Background radiation is always present, and its level can change with altitude and the amount of radioactive material present in soil and building materials.


Becquerel (Bq):
The international unit of measure for the quantity of radioactive material; one becquerel is that quantity of radioactive material in which one atom decays in 1 second. One becquerel is equivalent to 27 picocuries.


Biological Uptake:
The transfer of hazardous substances from the environment to plants, animals, and humans. This can be evaluated through environmental measurements (for example, by measuring the amount of the substance in an organ known to be susceptible to that substance). More commonly, biological dose measurements are used to determine whether exposure has occurred. The presence of a contaminant, or its metabolite, in human biological specimens, such as blood, hair, or urine, is used to confirm exposure and can be an independent variable in evaluating the relationship between the exposure and any observed adverse health effects.


Biota:
The animal and plant life of a particular region. As used in ATSDR's public health assessments, biota means animals, fish, and plants that humans would eat.


Body Burden:
The total amount of a chemical in the body. Some chemicals build up in the body because they are stored in tissues (e.g., fat, bone) or are eliminated very slowly.


Cancer:
A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control.


Carcinogen:
Any substance that can cause cancer.


Carcinoma:
A malignant neoplasm composed of epithelial cells, regardless of their derivation.


Case Study:
The medical or epidemiologic evaluation of a single person or a small number of individuals to determine descriptive information about their health status or potential for exposure through interview or biomedical testing.


Central Nervous System:
The part of the nervous system that includes the brain and the spinal cord.


CERCLA:
The Comprehensive Environmental Response, Compensation, and Liability Act of 1980, also known as Superfund. CERCLA's major provisions are designed to comprehensively address the problems associated with hazardous waste sites. This is the federal legislation that created ATSDR.


Chronic:
Occurring over a long period of time (1 year or more).


Committed Equivalent Dose:
The equivalent dose to organs and tissues of reference that will be received from an intake of radioactive material by an individual over a 50-year period following the intake for adults and from age of the intake to 70 years for children.


Committed Effective Dose:
The International Commission for Radiological Protection's term for the sum of the products of (1) the weighting factors applicable to each body organ or tissue that is irradiated and (2) the committed equivalent dose to the appropriate organ or tissue integrated over time (in years) following the intake. The integrated time is 50 years for an adult and from the time of intake to 70 years for children. The committed effective dose is used in radiation safety because it implicitly includes the relative carcinogenic sensitivity of the various tissues.


Comparison Value:
The estimated contaminant concentration in a specific medium that is not likely to cause adverse health effects, given a standard daily ingestion rate and standard body weight. Comparison values are calculated from the scientific literature available on exposure and health effects.


Concentration:
The amount of one substance dissolved or contained in a given amount of another. For example, sea water contains a higher concentration of salt than fresh water.


Contaminant:
Any substance or material unintentionally introduced into a medium (air, water, soil, sediment, food) which has the effect of rendering them toxic or otherwise harmful.


Contaminant of Concern:
Any chemical or substance that has the potential to adversely affect human receptors due to its concentration, distribution, and mode of toxicity.


Curie (Ci):
The traditional unit of measure for the quantity of radioactive material; one curie is that quantity of radioactive material in which 37 billion transformations occur per second, which is approximately the activity of 1 gram of radium. One curie is equivalent to 37 gigabecquerels.


Decay Product (Daughter Product, Progeny):
A radioisotope formed by the radioactive transformation of some other radioisotope.


Decay, Radioactive:
Transformation of the nucleus of an unstable nuclide by spontaneous emission of charged particles and/or photons.


Depleted Uranium:
Uranium in which the proportion of uranium 235 to total uranium of all isotopes is decreased from 0.72% to a lower value.


Dermal:
Referring to the skin. Dermal absorption is absorption through the skin.


Detection Limit:
The minimum concentrations that can be accurately and precisely measured by the laboratory and/or specified in a quality assurance plan.


Dose:
The amount of a substance that is absorbed or deposited in the body of an exposed organism for an increment of time. For chemicals, dose often takes body weight into account. For radioactive materials or radiation, dose denotes the quantity of radiation or energy absorbed and is a generic term for absorbed dose, equivalent dose, effective dose, committed equivalent dose, or committed effective dose.


Enriched Uranium:
Uranium in which the proportion of uranium 235 to total uranium of all isotopes is increased from 0.72% to a higher value.


Environmental Contamination:
The presence of unnatural or unintentional substances in the environment. From the public health perspective, environmental contamination should be addressed when it can affect the health and quality of life of people living and working near the contamination.


Epidemiology:
The study of the occurrence and causes of health effects in human populations. An epidemiological study often compares two groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect. The investigators try to determine if any factor is associated with the health effect.


Exposure:
Contact with a chemical by swallowing, breathing, or direct contact (such as through the skin or eyes). Exposure can be short-term (acute) or long-term (chronic).


Exposure Registry:
A system for collecting and maintaining, in a structured record, information on persons with documented environmental exposure(s). The exposure registry evolved from the need for fundamental information about the potential impact on human health of long-term exposure to low and moderate levels of hazardous substances.


Geographic Information System (GIS):
A computer hardware and software system designed to collect, manipulate, analyze, and display spatially referenced data. One can use a GIS to solve complex resource, environmental, and social problems.


Gray (Gy):
The international (SI) unit of absorbed radiation dose. One Gy equals the absorption of one joule of energy per kilogram of absorber. One gray equals 100 rad.


Hazard:
A hazard is only a source of risk if an exposure pathway exists and if exposures can have adverse consequences.


Health Outcome Data:
A major source of data for public health assessments. The identification, review, and evaluation of health outcome parameters are interactive processes involving health assessors, data source generators, and the local community. Health outcome data are community specific and may be derived from databases at the local, state, and national levels, as well as from data collected by private health care organizations and professional institutions and associations. Databases to be considered include morbidity and mortality data, birth statistics, medical records, tumor and disease registries, surveillance data, and previously conducted health studies.


Indeterminate Public Health Hazard:
A category assigned to sites or pathways for which no conclusions about public health hazard can be made because data are lacking.


Ingestion:
Swallowing (such as eating or drinking). Chemicals can get in or on food, drink, utensils, cigarettes, or hands, where they can be ingested. After ingestion, chemicals can be absorbed into the blood and distributed throughout the body.


Inhalation:
Breathing. One can be exposed to contaminants through inhalation, because inhaled contaminants can be deposited in the lungs, taken into the blood, or both.


Intermediate:
Occurring over a mid-length period of time. Intermediate exposure is exposure lasting 15 to 364 days.


Isotope:
Any nuclide of an element having the same number of protons in its nucleus (i.e., the same atomic number) as the element, but a different number of neutrons (i.e., a different mass number or atomic weight).


Media:
Soil, sediment, water, air, plants, animals, or any other parts of the environment that can contain contaminants.


Metabolism:
All the chemical reactions that enable the body to work. For example, food is metabolized (chemically changed) to supply the body with energy. Chemicals can be metabolized and made either more or less harmful by the body.


Metabolite:
Any product of metabolism.


Microcurie:
One-millionth of a curie, symbolized as µCi.


Millicurie:
One-thousandth of a curie, symbolized as mCi.


Minimal Risk Level (MRL):
An estimate of daily human exposure to a dose of radiation or a chemical that is likely to be without an appreciable risk of adverse noncancerous effects over a specified duration of exposure.


Morbidity:
Illness or disease. Morbidity rate is the number of illnesses or cases of disease in a population.


National Priorities List (NPL):
The U.S. Environmental Protection Agency's listing of sites that have undergone preliminary assessment and site inspection to determine which locations pose immediate threat to persons living or working near the release. These sites are most in need of cleanup.


No Apparent Public Health Hazard:
A category assigned to sites or pathways where human exposure to contaminated media is occurring or has occurred in the past, but is below a level of health hazard.


No Public Health Hazard:
A category assigned to sites for which data indicate no current or past exposure or no potential for exposure in the future and, therefore, no health hazard.


Picocurie:
One-trillionth of a curie, symbolized as pCi.


Plume:
An area of chemicals or radioactive materials in a particular medium, such as air or groundwater, moving away from its source in a long band or column. A plume can be a column of smoke from a chimney or contaminants moving with groundwater.


Public Health Hazard:
A category assigned to a site or pathway that poses a public health hazard because of long-term exposures to hazardous substances could result in adverse health effects.


Radiation:
The emission and propagation of energy in the form of waves. The term, when unqualified, usually refers to electromagnetic radiation, such as infrared, visible light, ultraviolet, X-ray, or gamma ray. It can also refer to corpuscular emissions, such as alpha and beta radiation.


Radioactivity:
The property of certain nuclides to spontaneously transform into other elements by emitting alpha or beta particles.


Registry:
A system for collecting and maintaining, in a structured record, information on specific persons from a defined population. Preliminary analyses and reviews are performed.


Rem:
The traditional unit of radiation equivalent dose and effective dose. The equivalent dose in rem is numerically equal to the absorbed dose in rad multiplied by a quality factor. One rem is equivalent to 0.01 sieverts (the international unit currently being used).


Risk:
In risk assessment, the probability that something will cause injury, combined with the potential severity of that injury.


Route of Exposure:
The way in which a person comes in contact with a chemical or radioactive substance. For example, drinking (ingestion) and bathing (skin contact) are two different routes of exposure to contaminants in water.


Sievert:
The international unit of radiation equivalent dose and effective dose. The equivalent dose in sieverts is numerically equal to the absorbed dose in gray multiplied by a quality factor. One sievert is equivalent to 100 rems (the traditional unit).


Specific Activity:
The total radioactivity of a given nuclide per gram of an element. This is a measure of the concentration of radioactivity. Specific activity can be expressed as µCi/gram, Bq/L, etc.


Superfund:
Another name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), which created ATSDR.


Superfund Amendments and Reauthorization Act (SARA):
The 1986 legislation that extensively amended CERCLA and broadened ATSDR's responsibilities in the areas of public health assessment, establishment and maintenance of toxicologic databases, information dissemination, and medical education.


Toxicological Profile:
A document (about a specific substance) in which ATSDR scientists interpret all known information on that substance and specify the levels at which people may be harmed if exposed to it. A toxicological profile also identifies significant data gaps in knowledge on substances and serves to initiate further research, when needed.


Urgent Public Health Hazard:
A category assigned to sites or pathways that pose a serious risk to public health as the result of short-term exposures to hazardous substances.


Vapor:
The gaseous state of a substance that, under ordinary conditions, is liquid or solid.


Volatile Organic Compounds (VOCs):
Substances containing carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen. These substances easily become vapors or gases. A significant number of the VOCs are commonly used as solvents (paint thinners, lacquer thinners, degreasers, and dry cleaning fluids).

Table of Contents

 
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