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PUBLIC HEALTH ASSESSMENT ADDENDUM

LETTERKENNY ARMY DEPOT
USA LETTERKENNY SOUTHEAST AREA
CHAMBERSBURG, FRANKLIN COUNTY, PENNSYLVANIA
AND
USA LETTERKENNY - PROPERTY DISPOSAL OFFICE AREA
CHAMBERSBURG, FRANKLIN COUNTY, PENNSYLVANIA


APPENDICES

Appendix 1: Public Health Assessment for Letterkenny Army Depot:

USA Letterkenny - PDO
CERCLIS NUMBER PA2210090054

USA Letterkenny - SE
CERCLIS NUMBER PA6213820503


September 30, 1988

The following section was not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services Branch, E-56
1600 Clifton Road NE, Atlanta, Georgia 30333


Appendix 2: Figures

Figure 1: Franklin County and Chambersburg Demographics, 1990

Franklin County Chambersburg

Total
persons
121,082 16,647

% Male

48.5 45.2
% Female 51.5 54.8

% White

96.7 90.6
% Black

2.3 7.2
% Other
races
1.0 2.2

% Younger
than 10

13.4 11.6
% Age 65
and older
14.5 22.3

Households*

45,675 7,238
Persons per
household

2.59 2.19
% Households
owner-occupied

72.7 51.5
% Households
renter-occupied

27.3 48.5
Median value,
owner-occupied
households, $

70,500 64,600
Median rent paid,
renter-occupied
households, $
273 273

Source: 1990 Census of Population and Housing (39)

*= A household is defined as an occupied housing unit, but does not include group quarters such as military barracks, prisons, and college dormitories.


Figure 2: Housing and Population Data for the Area Where Wells
Were Replaced Off-Site of the SE Area


Total
persons

568
Total area,
square miles

3.18
Persons per
square mile
179

% White

99.5
% Black

0.4
% American
Indian, Eskimo,
or Aleut

0.0
% Asian or
Pacific Islander

0.2
% Other
races
0.0

% Hispanic
origin
0.4

% Younger
than 18

22.6
% Age 65
and older
13.8

Households*

222
Persons per
household
2.56

% Households
owner-occupied

77.8
% Households
renter-occupied
22.2

% Persons in
group quarters
0.0

Mean value,
owner-occupied
households, $

~80,000
Mean rent paid,
renter-occupied
households, $
~300

*= A household is an occupied housing unit, but does not include group quarters such as military barracks, prisons, and college dormitories.

Source: 1990 Census of Population and Housing, Summary Tape File 1B Extract on CD-ROM (Pennsylvania) [machine-readable data files] (14).


Figure 3: Land Use of Areas
Surrounding Letterkenny Army Depot


Figure 4: Private Wells and Municipal
Water Wells Off-Site of the SE Area (Near Gate 6)


Figure 5: Private Wells and Municipal
Water Wells Outside the PDO Area (Near Gate 1)


Figure 6: Potential Contaminant
Source Areas: SE Area


Figure 7: Confirmed Source Areas: PDO Area


Figure 8: Groundwater Contour
Map for the PDO Area



Appendix 3: Tables

Table 1: Cancer Mortality Rates for Greene Township

OBSERVED1 AND EXPECTED2 TOTAL DEATHS, TOTAL CANCER DEATHS, AND
THE EIGHT STANDARD GROUPINGS OF CANCER3 FOR GREENE TOWNSHIP, 1970-1989


CAUSE OF DEATH ICDA4
CODE
ANNUAL
EXPECTED
DEATHS
OBSERVED
DEATHS
EXPECTED
DEATHS
SMR5 STATISTICAL6
SIGNIFICANCE

Total Deaths 000-999 83.86 828 922.46 0.898 95, L
Total Cancer Deaths 140-208 18.99 194 208.89 0.929 NS
Buccal Cavity and Pharynx 140-149 0.38 1 4.18 0.239 NS
Digestive System and Peritoneum 150-159 5.09 47 55.99 0.839 NS
Respiratory System 160-165 4.89 52 53.79 0.967 NS
Bone, Connective Tissure, Skin,
and Breast
170-175 2.17 26 23.87 1.089 NS
Genitourinary System 180-189 2.66 32 29.26 1.094 NS
Other and Unspecified Sites 190-199 2.12 15 23.32 0.643 NS
Leukemia 204-208 0.71 10 7.81 1.280 NS
Other Lymphatic and
Hemotopoietic Tissues
200-203 0.98 11 10.78 1.020 NS

1= Reported by Pennsylvania Department of Health (24, 36)

2= Expected numbers of deaths based on the age-sex distribution of the respective populations, 1980 U.S. Census of Population, and average annual age-sex state specific rates, 1979-1981

3= These groupings of cancer deaths are designated by the Pennsylvania Department of Health

4= International Classification of Diseases (ICDA), Adapted (Ninth Revision)

5= Standard Mortality Ratio (SMR) - Observed deaths divided by expected deaths) - An SMR of 1.00 means that the observed and expected numbers of deaths are equal

6= A statistical test (Poisson Model) was used to determine the probability of the ratio occurring by chance


Table 2: Cancer Mortality Rates for Hamilton Township

OBSERVED1 AND EXPECTED2 TOTAL DEATHS, TOTAL CANCER DEATHS, AND
THE EIGHT STANDARD GROUPINGS OF CANCER3 FOR HAMILTON TOWNSHIP, 1970-1989


CAUSE OF DEATH ICDA4
CODE
ANNUAL
EXPECTED
DEATHS
OBSERVED
DEATHS
EXPECTED
DEATHS
SMR5 STATISTICAL6
SIGNIFICANCE

Total Deaths 000-999 41.68 339 458.48 0.739 95, L
Total Cancer Deaths 140-208 9.65 79 106.15 0.744 95, L
Buccal Cavity and Pharynx 140-149 0.20 1 2.20 0.455 NS
Digestive System and Peritoneum 150-159 2.54 21 27.94 0.752 NS
Respiratory System 160-165 2.53 17 27.83 0.611 NS
Bone, Connective Tissue, Skin,
and Breast
170-175 1.14 10 12.54 0.797 NS
Genitourinary System 180-189 1.32 15 14.52 1.033 NS
Other and Unspecified Sites 190-199 1.08 9 11.88 0.758 NS
Leukemia 204-208 0.36 4 3.96 1.010 NS
Other Lymphatic and
Hemotopoetic Tissues
200-203 0.50 2 5.50 0.364 NS

1= Reported by Pennsylvania Department of Health (24, 36)

2= Expected numbers of deaths based on the age-sex distribution of the respective populations, 1980 U.S. Census of Population, and average annual age-sex state specific rates, 1979-1981

3= These groupings of cancer deaths are designated by the Pennsylvania Department of Health

4= International Classification of Diseases (ICDA), Adapted (Ninth Revision)

5= Standard Mortality Ratio (SMR) - Observed deaths divided by expected deaths) - An SMR of 1.00 means that the observed and expected numbers of deaths are equal

6= A statistical test (Poisson Model) was used to determine the probability of the ratio occurring by chance


Table 3: Cancer Mortality Rates for Letterkenny Township

OBSERVED1 AND EXPECTED2 TOTAL DEATHS, TOTAL CANCER DEATHS, AND
THE EIGHT STANDARD GROUPINGS OF CANCER3 FOR LETTERKENNY TOWNSHIP, 1970-1989


CAUSE OF DEATH ICDA4
CODE
ANNUAL
EXPECTED
DEATHS
OBSERVED
DEATHS
EXPECTED
DEATHS
SMR5 STATISTICAL6
SIGNIFICANCE

Total Deaths 000-999 14.30 112 157.30 0.712 95, L
Total Cancer Deaths 140-208 3.24 24 35.64 0.673 NS
Buccal Cavity and Pharynx 140-149 0.06 0 0.66 0.000 NS
Digestive System and Peritoneum 150-159 0.87 4 9.57 0.418 NS
Respiratory System 160-165 0.85 6 9.35 0.642 NS
Bone, Connective Tissure, Skin,
and Breast
170-175 0.34 4 3.74 1.070 NS
Genitourinary System 180-189 0.47 5 5.17 0.967 NS
Other and Unspecified Sites 190-199 0.25 4 2.75 1.455 NS
Leukemia 204-208 0.12 0 1.32 0.000 NS
Other Lymphatic and
Hemotopoietic Tissues
200-203 0.17 1 1.87 0.535 NS

1= Reported by Pennsylvania Department of Health (24, 36)

2= Expected numbers of deaths based on the age-sex distribution of the respective populations, 1980 U.S. Census of Population, and average annual age-sex state specific rates, 1979-1981

3= These groupings of cancer deaths are designated by the Pennsylvania Department of Health

4= International Classification of Diseases (ICDA), Adapted (Ninth Revision)

5= Standard Mortality Ratio (SMR) - Observed deaths divided by expected deaths) - An SMR of 1.00 means that the observed and expected numbers of deaths are equal

6= A statistical test (Poisson Model) was used to determine the probability of the ratio occurring by chance


Table 4: Environmental Contaminants: SE Area

CONTAMINANT
RANGE
µg/L
COMPARISON
VALUE
µg/L
REFERENCE
VALUE
      GROUNDWATER
Methylene Chloride
<5 - 155
4.7
CREG
Chlorobenzene
<0.6 - 260
200
RfD
Trichloroethene
<1.1 - 95,000
5.0
MCL
Trans-1,2-Dichloroethene
1.2 - 110,000
200
RfD
Tetrachloroethane
<1.3 - 34
5.0
MCL
1,1-Dichloroethene
<1.1 - 810
0.06
CREG
1,2-Dichloroethane
<0.6 - 58
0.38
CREG
      INDUSTRIAL WASTEWATER*
1,1,1-Trichloroethane
72 - 3,360
200
MCL,LTHA
Methylene Chloride
410 - 176,000
4.7
CREG
1,1,2,2-Tetrachloroethane
1.5 - 7,140
0.18
CREG
      SOIL1
mg/kg
mg/kg

Methylene Chloride
0.6 - 10
NA
NA
Trichloroethene
0.8 - 500
NA
NA
1,1-Dichloroethene
3 - 20
NA
NA
Lead
11.6 - 3,620
20 - 700
BMC22
Beryllium
7.49 - 11.8
0.16
CREG
    Source: Remedial Investigation of the SE Area, 1987 (2) - Unless otherwise indicated

    SE Area= Southeastern Area
    NA= Not Available (a value does not exist or it is under review)

    *= Prior to Treatment
    1= From former lagoon and landfill areas which are currently covered and/or undergoing remediation
    2= Background Metal Concentrations for Letterkenny in Southern Pennsylvania (40)


Table 5: Environmental Contaminants: PDO Area

CONTAMINANT

RANGE
µg/L

COMPARISON
VALUE

µg/L
REFERENCE
VALUE
      SURFACE WATER
Trichloroethene

<1.1 - 63

5
MCL
1,1,1-Trichloroethane
<1.7 - 501
200
MCL,LTHA
Trans-1,2-Dichloroethene
<1.2 - 89
200
RfD
Chloroform
<1.0 - 5.6
5.7
CREG
1,1-Dichloroethene
<1.1 - 3.1
0.06
CREG
1,1-Dichloroethane
ND - 41
0.38
CREG
Methylene Chloride
ND - 61
4.7
CREG
1,2-Dichloroethane
ND - <0.6
0.38
CREG
Tetrachloroethane
ND - 1.6
5
MCL
Chlorobenzene
ND - <0.6
200
RfD
      GROUNDWATER
Trichloroethene
<1.1 - 300
5
MCL
1,1,1-Trichloroethane
<1.7 - 1700
200
MCL,LTHA
1,1,2-Trichloroethane
<0.9 - <100
0.61
CREG
1,1,2,2-Tetrachloroethane
<0.9 - 4.7
0.18
CREG
Trans-1,2-Dichloroethene
<0.9 - 3200
200
RfD
Chloroform
<1.0 - 44
5.7
CREG
1,1-Dichloroethene
<0.9 - 110
0.06
CREG
      SOIL
mg/kg
mg/kg

Lead
22.8 - 50.1
20 - 700
BMC2
Trichloroethene
<0.1 - 6.8
NA
NA
1,1,1-Trichloroethane
<0.1 - 9.7
NA
NA
1,1-Dichloroethene
<0.1 - 1.4
NA
NA
    Source: Remedial Investigation of the PDO Area, 1987 (3) - Unless otherwise indicated

    PDO Area: Property Disposal Area
    NA= Not Available (a value does not exist or it is under review)
    ND= Not Detected

    1= Water Quality Evaluation of Rocky Spring Lake (42)
    2= Background Metal Concentrations for Letterkenny in Southern Pennsylvania (40)


Table 6: Off-Site Residential Wells Near the SE and PDO Areas and Off-Site Creeks and Springs Near the SE Area

CONTAMINANT
RANGE
µg/L
COMPARISON
VALUE

µg/L
REFERENCE
VALUE
      GROUNDWATER*
1,1-Dichloroethene
<1.1 - 8.6
0.06
CREG
Trans-1,2-Dichloroethene
<1.2 - 66
200
RfD
Chloroform
<1.4 - 2.8
5.7
CREG
1,1,1-Trichloroethane
<1.7 - 92
200
MCL,LTHA
Trichloroethene
<1.1 - 48
5
MCL
1,1,2,2-Tetrachloroethane
<1.0 - 13
0.18
CREG
1,2-Dichloroethane
<0.6 - 2.5
0.38
CREG
Chlorobenzene
<0.6 - 0.8
200
RfD
Carbon Tetrachloride1
ND - 0.81
0.27
CREG
Aluminum1
ND - 2310
50
SMCL2
Lead1
ND - 54.4
15
AL3
    SURFACE WATER**
1,1,1-Trichloroethane
<1.7 - 34
200
MCL,LTHA
Trans-1,2-Dichloroethene
<1.2 - 89
200
RfD
Trichloroethene
<1.1 - 63
5.0
MCL
Tetrachloroethane
ND - 1.6
100
RfD

    Source: Remedial Investigation of the SE Area, 1987 (2) - Unless otherwise indicated

    NA= Not Available
    *= Detected in groundwater and springs used for potable water
    **= Detected in Conococheague Creek, Rowe Spring/Run--(Off-Site)

    1= Draft, Remedial Investigation of the SE and PDO Area, respectively, 1992 (120, 121)
    2= Secondary MCL: Federal Registry, Vol. 56, Jan. 30, 1991 (43)
    3= EPA Action Level: Action Level for Lead in Drinking Water; Memorandum from the Office of Emergency and Remedial Response and Waste Program, U.S. EPA, Region IV (43)


Table 7: Potential and Completed Exposure Pathways*: SE Area

Source of
Contamination
Environmental Medium
Potential Human
Exposure Points
Potential Human
Exposure Routes
Potential Receptor
Population
Time
Element
   SE Area

Land Treatment, Storage, & Disposal Activities

Combined
Groundwater/Surface
Water Flow

(Emergence at Springs)
Off-Site Wells and Springs Used
for Potable Water Supply

(Residences and Businesses)

Dermal Contact, Ingestion of,
Metals & Dermal Contact,
Ingestion, and Inhalation of
Volatilized VOCs

Off-Site Residents East of
SE Boundary

COMPLETE:

PAST,
PRESENT, &
FUTURE
Off-Site Springs and Creeks
Where Groundwater Emerges

(Rowe and Pinola Springs,
Rowe Run, and Conococheague
Creek)
Dermal Contact,
Ingestion, and Inhalation of
Volatilized VOCs
Off-Site Residents,
Including Farmers, East of
SE Boundary
COMPLETE:

PAST,
PRESENT, &
FUTURE
Off-Site Farm Animals Watered
With Contaminated Water
Ingestion of Farm Animals and
Associated Products
The Public and Residents
East of SE Boundary
COMPLETE:

PAST,
PRESENT, &
FUTURE
Off-Site Crops Irrigated With
Contaminated Springs and
Creeks
Ingestion of Food Crops
The Public and Residents
East of SE Boundary
COMPLETE:

PAST,
PRESENT, &
FUTURE

*= Only Potential and Completed Pathways are presented in this table. Pathways which would be eliminated if proper safety equipment and procedures were followed (for example, remedial or maintenance personnel) are not discussed in the table. Those issues are addressed in the "Pathways Analyses" sections


Table 8: Potential and Completed Exposure Pathways*: PDO and AD/AS Areas

Source of
Contamination
Environmental Medium
Potential Human
Exposure Points
Potential Human
Exposure Routes
Potential Receptor
Population
Time
Element
   PDO Area

Land Treatment, Storage, & Disposal Activities

Combined Groundwater
and Surface Water Flow
On Site Surface Water:
Rocky Spring Creek/Lake

(Groundwater Discharge)
Dermal Contact, Ingestion,
& Inhalation of Volatilized VOCs
Installation Personnel, Their
Dependents & Guests:

Recreational Use of
Rocky Spring Creek/Lake
COMPLETE:

PAST,
CURRENT,
FUTURE:
On-Site Fish from:
Rocky Spring Creek/Lake
Ingestion of Fish
   AD/AS Area

Land Treatment, Storage, & Disposal
Activities

Soils
>
On-Site Deer Which Inhabit
the AD/AS Area:

Deer May Consume
Contaminated Soils
Ingestion of Venison
Hunters: Installation
Personnel, Their
Dependents, & Guests
POTENTIAL:

PAST,
PRESENT, &
FUTURE

* Only Potential and Completed Pathways are presented in this table. Pathways which would be eliminated if proper safety equipment and procedures were followed (for example, remedial or maintenance personnel) are not discussed in the table. Those issues are addressed in the "Pathways Analyses" section.


Appendix 4: Site Observations

Site Observations

The following site-specific observations were noted during the ATSDR site visit conducted during January 9-11, 1991.

Southeastern Area (SE)

The Industrial Waste Treatment Plant--Building 360: This plant is located in the industrial SE area of the installation, southeast of lagoons 361 and 362. ATSDR staff noted drums of hazardous waste stored on wooden pallets and on concrete floors outside the plant. The IWTP is near Gate 6 and adjacent to the East Patrol Road; it currently processes industrial wastewater from many industrial buildings within the SE Area. The resulting sludge is sent off site for treatment and disposal. The treated effluent is discharged into the headwaters of Rowe Run Stream. That stream flows off site to the east (28, 106).

Lagoons 361 and 362: The concrete-lined lagoons are now empty. Cracks were observed in the bottom of one lagoon, along with three white containers possibly containing residual sludge. One ATSDR staff member detected faint, sweet aromatic odors while walking around the lagoons. The monitoring wells, located east around the rim of the lagoons, were observed to be locked and in fairly good condition.

Groundwater Treatment System--Building 365: This metal building houses the groundwater treatment system which is pumping and treating groundwater contaminated with VOCs. ATSDR toured the inside of the building. An Organics Vapor Analyzer, (OVA) used to detect volatile organics needed to be repaired. Air monitoring stations were present but not currently working. The treated effluent from the GWTP is discharged into Rowe Run, adjacent to the IWTP treated outfall (28).

K-Area Soils: This area is now a vacant field where hazardous waste had been stored and disposed of. Adjacent to this field are stockpiles of raw materials, such as magnesium ore piles. These materials are stored there until they are needed. There was little vegetation at this area because it was viewed in the winter. In the summer, the K Area is primarily covered with weeds (28). One monitoring well was located at the former trenches, and two monitoring wells were near the edge of the East Patrol Road. These wells were last used in environmental studies performed during 1983-1985. The concrete lagoons are about 300 yards southeast of this area.

Property Disposal Area (PDO):

Fireman's Training Pit: About four months prior to the site visit, the area had been involved in a removal action. The sludge, concrete, and soils from this area were removed; the pit was then filled with clean fill and brought to grade. At the time of the site visit, this area was covered with a tarp and surrounded by a plastic fence, one foot in height to prevent wind erosion of the soil in the area.

Drum Storage Revetments Area: This fenced, 3,000 square feet area was used for storing drums of hazardous waste. It is located within the PDO scrapyard which is a storage area for drums, surplus vehicles, wood, metal, and other debris. The scrapyard is completely fenced to restrict access. The drums that were once stored in the Drum Storage Revetments Area have been removed; the area is now covered with weeds and grass. One staff member noticed odors similar to oils while observing this area.

Rocky Spring Lake: This recreational area is used for picnics, boating, and fishing by Letterkenny employees and guests. Signs were posted around the lake prohibiting wading and swimming, but allowing fishing. The amount of fish taken is unknown. A small pavilion with grills were noted on the east side of the lake; boats and bird houses were observed as well as geese and fish. An deactivation furnace for small range ammunition, part of the AD/AS Area, was observed uphill, northeast of the lake. Surface water drainage from that facility reportedly leads to this lake. The RI/FS is currently looking at the groundwater/surface water flow between the PDO and AD/AS Areas (28).

Off-Site:

Rowe Spring: The surface waters of Rowe Run and groundwater flow off-site from the SE Area of Letterkenny. The groundwater surfaces about 1.5 miles east of the SE Area boundary as Rowe Spring, supplementing the flow of Rowe Run Creek at the residence of a cattle farmer on Rowe Run Road. This residence is located about 20 feet from the spring from which approximately 18 head of livestock were wading in and drinking from five inches of water flowing into the creek. No stressed vegetation was observed around the stream; mosses, algae, and grasses were growing there. An egg hatchery, numerous farms, and numerous vegetable and fruit gardens were predominant in this agricultural area. Some mobile homes, along with many brick and wood homes were noted. This area as well as the Pinola Spring area are used for small game hunting. Various farms in this area utilize this water for irrigation of crops, lawns, and gardens and watering of farm animals which may include cattle, dairy cows, pigs, and poultry (29, 30).

Pinola Spring: The groundwater system again surfaces as Pinola Spring about 3.5 miles east of Letterkenny. The stream had a steady flow and the area supported aquatic life and plants (minnows, mosses, and grasses). Houses similar to those seen at Rowe Spring along with fruit and vegetable gardens were noted; however, this area appeared to have more houses under construction. Three houses under construction were located less than 300 yards from the spring, and one residence was located approximately 100 feet from where the stream surfaces.

Ammunition Disposal and Storage Area (AD/AS Area):

Observation was limited due to the large size of this area and type of activities occurring there.


Appendix 5: Comparison Values, Health Guidelines, and Quantitative Units

Comparison Values, Health Guidelines, and Quantitative Units

    Comparison values for ATSDR public health assessments are contaminant concentrations in specific media that are used as an aid to select contaminants for further evaluation. Those values usually appear in the Environmental Contamination and Other Hazards and in the Public Health Implications section of this document. Health guidelines, which usually appear in the Public Health Implications section of this public health assessment, provide concentrations used to estimate a dose at which health effects might or might not be observed. Quantitative units express the amount of contaminant that has been detected in specific media. Those units are usually first discussed in the Environmental Contamination and Other Hazards section, and they are described below.

    Comparison Values and Health Guidelines

* ADI = Acceptable Daily Intake
* AL = Action Level for Lead in Drinking Water, EPA
* BMC = Background Metal Concentration, Letterkenny
* CREG = Cancer Risk Evaluation Guides
* CSF = Cancer Slope Factor
* EMEG = Environmental Media Evaluation Guides
* LTHA = Lifetime Health Advisory
* MCL = Maximum Contaminant Level
* MRL = Minimal Risk Level
* NOAEL = No Observed Adverse Effect Level
* LOAEL = Lowest Observed Adverse Effect Level
* RfD = Reference Dose
* RfC = Reference Concentration

      Quantitative Units

* ppm = parts per million, (milligrams per liter, mg/L of water)
* ppb = parts per billion, (micrograms per liter, µg/L of water)
* mg/kg = milligrams per kilogram (mg/kg; soil, sediment, or solid)
* µg/kg = micrograms per kilogram (µg/kg; soil, sediment, or solid)
* kg = kilogram
* mg = milligram
* µg = microgram
* L = liter

Definition of Comparison Values and Health Guidelines

ADI The Acceptable Daily Intake (ADI) is an estimate of the daily exposure dose that is likely to be without harmful effects even if continued exposure occurred over a lifetime. These intakes are established by EPA.

AL Action levels are established by the U.S. EPA. The action level usually applies to drinking water and may be used as an alternative comparison value when an MCL does not exist or is being reevaluated by EPA.

BMC Background concentrations, such as metals, for the state, region, or nation can be used for comparison, when background samples for the medium of concern, such as soil, have not been collected and when other comparison values do not exist. Background concentrations can be used provided the medium has the same basic characteristics as the medium of concern at the site.

CREG Cancer Risk Evaluation Guides are derived by ATSDR from the EPA Cancer Slope Factor (CSF). They represent an estimated concentration in water, soil, or air that would be expected to cause no more than one excess cancer in a million (10E-6) persons exposed over a lifetime.

CSF A Cancer Slope Factor is usually, but not always, the upper 95th percentile confidence limit of the slope for the dose-response curve. A CSF is developed for a probable or likely carcinogen and is expressed as (mg/kg/day)-1. When data permit, slope factors listed in IRIS are based on absorbed doses, although many of them are based on administered doses.

EMEG Environmental Media Evaluation Guides are derived by ATSDR from ATSDR's Minimal Risk Levels (MRLs) and factor in body weight and ingestion rates. An EMEG is the concentration of a particular contaminant in water, soil, or air at which daily human exposure is unlikely to result in adverse noncancerous effects.

LTHA A Lifetime Health Advisory represents contaminant concentrations that EPA considers protective of noncancerous health effects during a lifetime (70 years) of exposure. Drinking water concentrations are developed to predict acceptable exposure levels for both adults and children when data on a NOAEL or LOAEL exist from animal or human studies. LTHAs are not enforceable standards.

MCL Maximum Contaminant Levels represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day (for an adult). MCLs are enforceable standards.

MRL A Minimal Risk Level (MRL) is an estimate of daily human exposure to a chemical that is likely to be without an appreciable risk of adverse noncancerous effects over a specified duration of exposure. MRLs are based on human and animal studies and are reported for acute (< 14 days), intermediate (15-364 days), and chronic (> 365 days) exposures. MRLs are published in ATSDR Toxicological Profiles for specific chemicals.

LOAEL A LOAEL or Lowest Observed Adverse Effect Level is the lowest exposure level at which there are statistically or biologically significant increases in frequency or severity of adverse health effects between the exposed population and its appropriate control group. LOAELs may be used to estimate a dose at which people are not expected to develop adverse noncancerous health effects. LOAELS are published in ATSDR Toxicological Profiles for specific chemicals.

NOAEL A NOAEL or No Observed Adverse Effect Level is an exposure level at which there are no statistically or biologically significant increases in frequency or severity of adverse health effects between the exposed population and its appropriate control group. NOAELs may be used to estimate a dose at which people are not expected to develop adverse noncancerous health effects. NOAELS are published in ATSDR Toxicological Profiles for specific chemicals.

RfC A Reference Concentration, derived by EPA, is an estimate of the daily inhalation exposure to a contaminant (including sensitive subpopulations) that is unlikely to cause noncancerous health effects during a lifetime exposure (chronic RfD) or during a limited time interval (subchronic RfC).

RfD A Reference Dose, derived by EPA, is an estimate of the daily oral exposure to a contaminant (including sensitive subpopulations) that is unlikely to cause noncancerous health effects during a lifetime exposure (chronic RfD) or during a limited time interval (subchronic RfC).


Appendix 6: Public Comments on Letterkenny Army Depot Public Health Assessment


Public Comments on Letterkenny Army Depot
Public Health Assessment

The following responses were received by ATSDR in response to the public comment period for the Letterkenny Army Depot Public Health Assessment (106, 119). The list of comments does not include editorial comments concerning word spellings, sentence syntax, etc. It also does not include comments on accuracy of stated facts. If the accuracy of a statement was questioned, the statement was verified and corrected. Comments which requested that information be added to the document without providing documented sources of that information are not addressed here. Portions of the comments below were paraphrased by ATSDR for brevity or clarity. If the same comments were received from more than one source, only one comment and response is listed. The page(s) that the comment is referring to is bolded in parentheses after the comment number.

Comment 1 (General Comments): Does ATSDR consider a medium contaminated when chemical concentrations are greater than MCLs or greater than the detection level? Please specify what your agency considers to be contaminated.

Response to Comment 1: The Environmental Contamination and Other Hazards section explains what a comparison value is, and Appendix 5 contains definitions of each comparison value used in the public health assessment. The use of "contaminated" has been qualified to reflect chemicals that have been detected above ATSDR comparison values. ATSDR's comparison values may include not only EPA-derived comparison vales such as MCLs, but also ATSDR-derived comparison values such as RMEGs. When a chemical is detected above comparison values, those chemicals are placed in contaminants-of-concern tables. Also, in cases where comparison values do not exist, a chemical that is present above detection values is listed as a contaminant of concern. The listing of a contaminant in the text or in contaminants-of-concern tables does not mean that it will cause adverse health effects if exposure occurs at the specified concentrations. Rather, the listing of a contaminant indicates that it will be discussed further in this public health assessment. The potential for adverse health effects resulting from exposure to contaminants of concern is discussed in the Public Health Implications section of this document.

Comment 2 (General Comments): When discussing the various chemical parameters in the toxicological evaluation, please indicate each parameter's carcinogenic group.

Response to Comment 2: The carcinogenic group (i.e., including B2, C, or D ) has been specified and defined for each chemical via route of exposure in the Toxicological Evaluation section of the public health assessment. Chemicals that are currently being evaluated for carcinogenicity or are not classifiable as carcinogens (due to lack of studies indicating carcinogenicity) do not have a carcinogenic group. The Toxicological Evaluation section explains this for T-1,2-DCE and 1,1,1,-TCA. Although TCE is currently being re-evaluated for carcinogenicity, it is recognized to be a Group B2 carcinogen, until further studies show otherwise. This distinction has been added to the document for clarity.

Comment 3 (General Comments): Within the toxicological evaluation, some of the parameters have dermal contact listed as route of exposure while some do not (i.e., a dermal contact route is considered for 1,1-DCE, but not for TCE). Since all of the parameters are volatile organics, what is the rationale for this inconsistent treatment? Also, would the property of high volatility, while disqualifying the dermal route for some chemicals, make the inhalation route that much more of a concern for these same chemicals? Would the ingestion and inhalation routes remain equivalent for these chemicals?

Response to Comment 3: All exposure routes, if significant, were considered to be equal and all routes were evaluated for adverse health effects. Clarification of the report now indicates that all routes were evaluated for those VOCs. Past exposures to the metals lead and aluminum were also evaluated, but only for ingestion, since dermal and inhalation exposure to lead from showering are not likely to be significant compared to ingestion of lead in drinking water.

Comment 4 (General Comments): The AD/AS site is included in this document. Since this site is not a NPL site and there is no evidence that a release from this site has occurred, why is it included?

Response to Comment 4: The AD/AS Area is discussed in this assessment because a site investigation indicated that chemicals have been detected at nine Solid Waste Management Units, most of which are in the AD/AS Area. Those nine units are also undergoing additional environmental characterization in 1993. It is ATSDR's practice and public health mission to discuss areas that may contribute to potential pathways or areas that may require more environmental sampling to assess potential and/or completed exposure pathways.

Comment 5 (Page 2, Paragraph 5): Please state that people were potentially exposed to levels that may result in adverse health effects.

Response to Comment 5: The word "may" has been added to the text and was previously noted on pages 37 and 60.

Comment 6 (Page 7, Paragraph 2): Please clarify that the homes and businesses which were hooked up to the Guilford Water Authority had VOC contamination above MCLs.

Response to Comment 6: This has now been clarified throughout the document when that past event is mentioned.

Comment 7 (Page 16, Paragraph 2): Please provide discussion regarding where the comparison values may come from, such as MCLs, ALs, CSFs and so forth.

Response to Comment 7: A description of comparison values and other factors that determine how chemicals of concern are chosen as well as well as who they are developed by have been further clarified in the Introduction portion of the Environmental Contamination and Other Hazards section of this document. Also, Appendix 5 contains descriptions of the comparison values used in the Public Health Assessment.

Comment 8 (Page 33, Paragraph 3): It is felt that the pathway of occasional accidental and recreational exposure should be characterized as a potential pathway rather than as a completed pathway.

Response to Comment 8: Since VOCs have been historically detected (in the springs) for that pathway, it is completed. But they are not at concentrations likely to cause adverse health effects.

Comment 9 (Page 37, Paragraph 1): Please state explicitly why multiple exposures have not been calculated.

Response to Comment 9: Multiple exposure routes have been evaluated for potential adverse health effects. We recognize that potential multiple chemical exposures occurred and have taken them into consideration. However, there is a lack of published data on the health effects from chemical mixtures. ATSDR will re-evaluate the toxicologic effects from multiple-chemical exposures as new information becomes available in the scientific literature.

Comment 10 (Page 64, Paragraph 1): Will ATSDR update this report on a yearly basis?

Response to Comment 10: A public health assessment is an ongoing process. ATSDR revises final documents if new information about the environment, community health concerns, and health outcome data becomes available and is found to change previous conclusions and recommendations.

Comment 11 (Pages 37-54): Good scientific support is needed for the assertions that past exposure to these VOCs in these wells for greater than 5 (or 1) years may be associated with an increased risk for developing cancer, that for some VOCs this is only true for ingestion, and that for others it is true for ingestion and inhalation. Please supply and explain the basis for these assertions in the text.

Response to Comment 11: It is good public health practice to evaluate the maximum concentrations for potential adverse health effects, when the exact duration of exposure and ranges of concentrations are unknown. Evaluation of potential risk for cancerous adverse health effects have been evaluated for completed exposure pathways using the maximum concentrations detected and an estimated exposure duration of approximately 33 years.

Comment 12 (Pages 37-54): Show an equal allowable Acceptable Daily Intake (ADI) for each contaminant and route of exposure in mg/kg/day for adults and children if that is indeed the case. If children are more sensitive to the chemical (e.g., to lead) then the allowable ADI should be even lower for the child than that for the adult.

Response to Comment 12: The relative intake of a child is greater than an adult due to the different body weight and intake rate of children. The Allowable Daily Intake (ADI) for children (mg/kg/day) may appear to be higher than adults because of those factors, but this is not the case. Where Allowable Daily Intakes for children and adults are discussed, this clarification has been made.

Comment 13 (Page 52): Although the EPA does not have a toxicity value for lead, they have a model that predicts blood lead levels in a population of children given certain intakes of lead by the various routes of exposure. Would it be helpful to use this model with the water intake alone, or with defaults for the other intakes?

Response to Comment 13: The concentrations of lead detected in drinking water wells have been used to estimate an increase in blood-lead level for children, given lead exposure via ingestion. Only the ingestion route has been evaluated for adverse health effects, because lead does not readily volatilize from shower heads and lead does not readily permeate the skin during showering. While the lead levels detected in drinking water wells are not expected to result in adverse health effects, exposure to lead in children may add to their lead body burden. Therefore, recommendations were made to resample the six private wells that remain in service and were detected with lead above the EPA action level of 15 µg/L. Also, residents with lead detected in well water above the EPA action level should be reminded of corrective measures that can be taken to reduce lead levels in their water. During 1993, Letterkenny is planning to sample those wells near the PDO Area at the wellhead and at the tap, and they plan to conduct hydrogeological studies to help identify the source of lead.


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