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PUBLIC HEALTH ASSESSMENT

Select PCB Exposure Pathways

AGANA POWER PLANT
MONGMONG, GUAM


VI. CONCLUSIONS

See Appendix B for definitions of conclusion categories.

  1. Eating fish, eels, and snails from the Agana Swamp and River poses no past or current public health hazard from PCB, dioxin, or PAH contamination. ATSDR classifies this exposure as no apparent public health hazard because although people were exposed, the levels were so low as to not present a hazard.

  2. Eating fish, eels, and snails from the Agana Swamp and River poses a current but indeterminate public health hazard from biological contamination. It is possible that the Agana Swamp and River contain biologic contamination, although the levels of bacteria, viruses, parasites, and other infectious agents are unknown.

  3. Gardening or playing in the drainage ditches near the Agana Power Plant poses no past or current public health hazard. ATSDR classifies this exposure as no apparent public health hazard because although people were exposed, the levels were so low as to not present a hazard. In addition, because the PCB contamination was the result of small spills, the PCB contamination was not likely to have been higher in the past.

  4. Swimming or wading in the Agana Swamp and River poses no past or current public health PCB-related hazard. ATSDR classifies this exposure as no apparent public health hazard because although people were exposed, the levels were so low as to not present a hazard. Relatively low levels of PCBs have been found in sediment from the Agana Swamp, but PCBs do not dissolve easily in water and would have been diluted by the large volume of water.

  5. Swimming or wading in the Agana Swamp and River poses a current indeterminate public health hazard from biological contamination. It is possible that the Agana Swamp and River contain biologic contamination, although the levels of bacteria, viruses, parasites, and other infectious agents are unknown.

VII. PUBLIC HEALTH ACTION PLAN

The public health action plan (PHAP) for the Agana Power Plant recommends actions for ATSDRand other government agencies at and in the vicinity of the site. The PHAP is designed to ensurethat this public health assessment not only identifies public health hazards but provides a plan ofaction designed to mitigate and prevent adverse human health effects resulting from exposure tohazardous substances in the environment. The public health actions completed and to beimplemented are as follows:

A. Completed Actions

  1. The Navy has done extensive remediation and sampling both on the Agana Power Plant property and in surrounding areas. They have issued several fact sheets and reports for the community and held many public meetings to keep the people of Mongmong informed of their findings and activities, and to solicit their input.

  2. ATSDR has visited the APP site and surrounding community, held public availability sessions for the people of Mongmong, and met with several representatives from Guam government agencies and the congressman from Guam. Since 2000, ATSDR has also issued several fact sheets, preliminary findings, and a site summary public health consultation for the Mongmong/APP area (ATSDR 2000a; ATSDR 2000b; ATSDR 2002a; ATSDR 2002b).

B. Planned Actions

ATSDR will be preparing another document for the other five issues from the health consultationnot covered in this document (see Introduction).

C. Recommended Actions

  1. ATSDR recommends that people reduce the possibility of exposure to biologic hazards in foods harvested from the Agana Swamp and River by thoroughly cooking foods to kill all bacteria, viruses, parasites, and other infectious agents, avoid handling of raw foods if a person has open cuts or wounds, and disinfect surfaces and utensils that have contacted raw foods before exposing other foods.

  2. ATSDR recommends that as funding becomes available the government of Guam consider sampling of snails and other organisms on Guam for a baseline evaluation of micro-organisms.

  3. ATSDR recommends that if people have open cuts and wounds that they avoid swimming or wading the Agana Swamp and River. This will prevent exposure to biologic hazards and, because they will not ingest the water, will also reduce the risk of gastrointestinal problems such as diarrhea and abdominal pain.

  4. ATSDR continues to support recommendations by health and regulatory agencies to reduce exposure to PCBs and other chemicals. As a prudent public health action, people should follow all fish and seafood consumption advisories issued by federal and Guam agencies. Individuals and families should eat healthy diets with a variety of foods. Potential exposure to many chemicals will be reduced by eating a variety of foods—including fish and seafood—and using food preparation and cooking techniques that remove fat (with associated PCBs and dioxin like compounds) from the food that is eaten. For most people, adjusting their diet to fall within the Federal Dietary Guidelines will result in multiple health benefits, including reduced exposure to PCBs and dioxin-like compounds. The dietary guidelines provide the best scientifically based advice on what constitutes a healthy diet and provide guidance on how to plan a varied diet by choosing individual foods from a number of food groups. ATSDR continues to suggest that individuals and families discuss their health concerns with their physician or health care provider and have routine physicals.

PREPARERS OF THE REPORT

Charles Grosse
Environmental Health Scientist
Federal Facilities Assessment Branch
Division of Health Assessment and
Consultation

Aimee Tucker Treffeltti
Environmental Health Scientist
Federal Facilities Assessment Branch
Division of Health Assessment and
Consultation


Contributors

Kevin Liske
GIS Analyst
Programs Evaluation Records and Information Services Branch
Division of Health Assessment and Consultation


Reviewers

Sandy Issaacs
Branch Chief
Federal Facilities Assessment Branch
Division of Health Assessment and
Consultation

Gary Campbell
Section Chief, Defense Section
Federal Facilities Assessment Branch
Division of Health Assessment and
Consultation

Diane Jackson
Environmental Engineer
Federal Facilities Assessment Branch
Division of Health Assessment and
Consultation

Allan Susten
Director for Science
Office of the Director
Division of Health Assessment and
Consultation

Carole Hossom
Environmental Health Scientist
Federal Facilities Assessment Branch
Division of Health Assessment and
Consultation

Wallace Sagendorph
Writer/Editor
Office of Programs and External Affairs


REFERENCES

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[ATSDR] Agency for Toxic Substances and Disease Registry. 2000b. Health consultationoutlining various exposure issues from initial site visit-May 2000 to Mongmong and the AganaPower Plant, Mongmong, Guam. Atlanta: US Department of Health and Human Services.

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[ATSDR] Agency for Toxic Substances and Disease Registry. 2002a. Fact sheet: communityquestions and answers on PCB contamination and health, Agana Power Plant, Guam. Atlanta: USDepartment of Health and Human Services.

[ATSDR] Agency for Toxic Substances and Disease Registry. 2002b. Fact sheet: update onATSDR's public health assessment for Agana Power Plant, Guam. Atlanta: US Department ofHealth and Human Services.

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US Navy. 2001. Dry well investigation and abandonment Agana Power Plant, Guam. Honolulu:Prepared for the Navy by Earth Tech, Inc.

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US Navy. 1999a. Fact sheet no. 3: Navy performs PCB-impacted soil removal action at formerAPP.

US Navy. 1999b. Fact sheet no. 5: Navy performs PCB-impacted soil removal action at former agana power plant (APP), Mongmong-Toto-Maite and Agana, Guam.

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US Navy. Final remediation verification report, time-critical removal action of pcb-contaminatedsoil, Agana Power Plant, Agana, Guam. September 1999d. Agana: Prepared for the Navy by OHMRemediation Services Corporation, Inc.

US Navy. 1999e. Fact sheet no. 11: water flow information and the Agana power plant (APP).

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US. Navy. 1998a. Fact sheet no. 1: Navy investigates old Agana power plant.

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US Navy. 1996. Final remedial investigation for dry cleaning shop, NEX Garage, USS Proteus, andOrote Landfill. Agana: Prepared for the Navy by Ogden Environmental and Energy Services Co.,Inc.

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Agency for Toxic Substances and Disease Registry. 1995. Toxicological profile for polycyclicaromatic hydrocarbons (PAHs). Atlanta: US Department of Health and Human Services.

Australia New Zealand Food Authority (ANZFA). 2001. The 19th Australian total diet survey, a total diet survey of pesticide residues and contaminants. Available at: URL: http://www.foodstandards.gov.au/_srcfiles/19th%20ATDS.pdf . (Accessed July, 2002)

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Guam Cancer Registry. 1999. Draft: Has PCB contamination of the environment caused anincreased incidence of cancer in Mongmong? Agana: Guam Department of Health and SocialServices.

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Hutzinger O, Choudhry GG, Chittim BG, Johnston LE. 1985. Formation of polychlorinateddibenzofurans and dioxins during combustion, electrical equipment fires and PCB incineration.Environ Health Perspect 60:3-9.

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FIGURES

Site Location Agana Power Plant
Figure 1. Site Location Agana Power Plant

Agana Power Plant Drainage Areas
Figure 2. Agana Power Plant Drainage Areas


APPENDICES

APPENDIX A:

POSSIBLE EXPOSURE SITUATIONS FOR PCBS FROM THE AGANA POWER PLANT
Situation Conclusion Category* Recommendations
1. People Eating Foods from Agana Swamp and River

a) Fish, eels, or snails, including aquatic snails, from Agana Swamp or River have detectable levels of several contaminants, but the contaminant levels are below those that would pose a health hazard. Bacterial contamination has been detected in Agana Swamp; therefore, bacterial contamination of fish is possible.

a) Chemical
Past and Current- No Apparent Public Health Hazard

Biologic
Past and Current - Indeterminate Public Health Hazard

a) Because fish, eels, and snails could have biological contaminants, the foods should be thoroughly cooked before eating to avoid gastrointestinal problems, and raw food should not be handled by people who have open cuts or wounds. ATSDR recommends further characterization of biologic hazards in the swamp through sampling. In addition, as funding becomes available, the government of Guam should consider a baseline evaluation of snails and other organisms for biologic hazards.

b) PCBs were not detected in fruits and vegetables grown and harvested in the Agana Swamp. Only one sample of taro root was analyzed for dioxins. A detectable level was found, but was below a level that would pose a health hazard. b) Chemical
Past and Current- No Apparent Public Health Hazard
b) ATSDR concludes that fruits and vegetables grown and harvested in the Agana Swamp do not pose a public health hazard from chemical contaminants.
6. Playing in the Dirt or Runoff Ditches and Gardening

Soil samples from the two off-site drainage ditches and nearby residential areas show low levels of PCB contamination. Still, the contaminant levels are below those that would pose a health hazard.

Chemical
Past and Current- No Public Health Hazard
ATSDR concludes that the soils from and around the runoff ditches and in the residential areas are safe to touch during activities such as playing or gardening, and do not pose a health hazard from accidental ingestion.
7. Swimming and Wading in Agana Swamp and River

The Outfall Drainage Area from the APP leads to the Agana Swamp. Some sediment samples from the Agana Swamp and River have low concentrations of PCBs. These levels are lower than those that would pose a health hazard. In addition, PCBs don't easily dissolve in water and any runoff from the APP would have been diluted by the large volume of water in the swamp. Therefore, touching the water would not have posed a chemical health hazard. However, since the 1960s biological contamination in the swamp has been documented by the U.S. Geological Service (USGS).

Chemical
Past and Current- No Apparent Public Health Hazard

Biologic
Past and Current- Indeterminate Public Health Hazard

ATSDR concludes it was safe to swim and wade in the Agana Swamp and River in the past, and currently it is safe from chemical contamination. Nevertheless, due to the biological contamination, people with open cuts or wounds who swim or wade might have an increased likelihood of infection, and those who accidentally ingest the water could have gastrointestinal problems such as diarrhea and abdominal cramps.

* See Appendix B


APPENDIX B:

ATSDR HAZARD CATEGORIES
Category Definition Criteria
A. Urgent public health hazard This category is used for sites that pose an urgent public health hazard as the result of short-term exposures to hazardous substances. • evidence exists that exposures have occurred, are occurring, or are likely to occur in the future AND
• estimated exposures are to a substance(s) at concentrations in the environment that, upon short-term exposures, can cause adverse health effects to any segment of the receptor population AND/OR
• community-specific health outcome data indicate that the site has had an adverse impact on human health that requires rapid intervention AND/OR
• physical hazards at the site pose an imminent risk of physical injury
B. Public health hazard This category is used for sites that pose a public health hazard as the result of long-term exposures to hazardous substances. • evidence exists that exposures have occurred, are occurring, or are likely to occur in the future AND
• estimated exposures are to a substance(s) at concentrations in the environment that, upon long-term exposures, can cause adverse health effects to any segment of the receptor population AND/OR
• community-specific health outcome data indicate that the site has had an adverse impact on human health that requires intervention
C. Indeterminate (potential) public health hazard This category is used for sites with incomplete information. • limited available data do not indicate that humans are being or have been exposed to levels of contamination that would be expected to cause adverse health effects; data or information are not available for all environmental media to which humans may be exposed AND
• there are insufficient or no community-specific health outcome data to indicate that the site has had an adverse impact on human health
D. No apparent public health hazard This category is used for sites where human exposure to contaminated media is occurring or has occurred in the past, but the exposure is below a level of health hazard. • exposures do not exceed an ATSDR chronic MRL or other comparable value AND
• data are available for all environmental media to which humans are being exposed AND
• there are no community-specific health outcome data to indicate that the site has had an adverse impact on human health
E. No public health hazard This category is used for sites that do not pose a public health hazard. • no evidence of current or past human exposure to contaminated media AND
• future exposures to contaminated media are not likely to occur AND
• there are no community-specific health outcome data to indicate that the site has had an adverse impact on human health


APPENDIX C: CALCULATION OF TOTAL DIOXINS AS 2,3,7,8-TCDD TEQ

Dioxins, furans, and dioxin-like PCB congeners are evaluated based on total toxicity equivalency factors (TEF) as related to the most toxic dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). The TEFs are based on known toxicological information for each compound. A total equivalency (TEQ) is calculated by multiplying the chemical concentration by the TEF, and then summing all the values. There are two main sets of TEFs, the International TEFs (I-TEFs), which is used by the EPA, and the World Health Organization TEFs (WHO-TEFs). One of the primary differences between the two methods is that the WHO method uses TEFs for dioxin-like PCB congeners. It is often necessary to calculate the 2,3,7,8-TCDD TEQ using both methods because comparison values may be expressed as either I-TEQ or WHO-TEQ. The I-TEFs and the WHO-TEFs are listed in Table C-1.

Table C-1:

Total Equivalency Factors (TEFs) for Dioxins, Furans, and PCB-like Congeners
Compound WHO-TEF I-TEF
1,2,3,4,6,7,8,9-octachlorodibenzofuran 0.0001 0.001
1,2,3,4,6,7,8-heptachlorodibenzofuran 0.01 0.01
1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin 0.01 0.01
1,2,3,4,7,8,9-heptachlorodibenzofuran 0.01 0.01
1,2,3,4,7,8-hexachlorodibenzofuran 0.1 0.1
1,2,3,4,7,8-hexachlorodibenzo-p-dioxin 0.1 0.1
1,2,3,6,7,8-hexachlorodibenzofuran 0.1 0.1
1,2,3,6,7,8-hexachlorodibenzo-p-dioxin 0.1 0.1
1,2,3,7,8,9-hexachlorodibenzofuran 0.1 0.1
1,2,3,7,8,9-hexachlorodibenzo-p-dioxin 0.1 0.1
1,2,3,7,8-pentachlorodibenzofuran 0.05 0.05
1,2,3,7,8-pentachlorodibenzo-p-dioxin 1 0.5
2,3,4,6,7,8-hexachlorodibenzofuran 0.1 0.1
2,3,4,7,8-pentachlorodibenzofuran 0.5 0.5
2,3,7,8-tetrachlorodibenzofuran 0.1 0.1
2,3,7,8-tetrachlorodibenzo-p-dioxin 1 1
octachlorodibenzo-p-dioxin 0.0001 0.001
PCB-105 0.0001 NA*
PCB-114 0.0005 NA
PCB-118 0.0001 NA
PCB-123 0.0001 NA
PCB-126 0.1 NA
PCB-156 0.0005 NA
PCB-157 0.0005 NA
PCB-167 0.00001 NA
PCB-169 0.01 NA
PCB-189 0.0001 NA
PCB-77 0.0001 NA
PCB-81 0.0001 NA

*NA = not applicable


APPENDIX D: INFORMATION ON HOW ATSDR ASSESSES EXPOSURE

What is meant by exposure?

People can only be exposed to a chemical if they come in contact with that chemical. Contact(exposure) can occur by breathing, eating, or drinking a substance containing the contaminant orby skin contact with a substance containing the contaminant.

How do ATSDR scientists determine which exposure situations and contaminants to evaluate?

ATSDR's public health assessments are exposure, or contact, driven. Chemical contaminantsdisposed of or released into the environment have the potential to cause adverse health effectsunder certain conditions. That said, however, a release does not always result in exposure.

ATSDR scientists evaluate site conditions to determine if people could have been (a pastscenario), are (a current scenario), or will be (a future scenario) exposed to site-relatedcontaminants. When evaluating exposure pathways, ATSDR identifies whether exposure tocontaminated media (soil, water, air, waste, or biota) has occurred, is occurring, or will occurthrough ingestion, dermal (skin) contact, or inhalation.

If exposure was or is possible, ATSDR applies a weight-of-evidence approach as to whetherpeople might develop adverse health effects. First, ATSDR scientists select contaminants forfurther evaluation by comparing them against health-based values. Comparison values aredeveloped by ATSDR from scientific literature available on exposure and health effects. Thesecomparison values are derived for each of the different media and reflect the estimatedcontaminant concentration that is not likely to cause adverse health effects for a given chemical,assuming a standard daily contact rate (e.g., amount of water or soil consumed or amount of airbreathed) and body weight. Comparison values are not thresholds for adverse health effects. ATSDR comparison values establish contaminant concentrations many times lower than levels atwhich no effects have been observed in experimental animals or human epidemiological studies.Some of the comparison values used by ATSDR scientists include ATSDR's environmental mediaevaluation guides (EMEG), reference dose media guides (RMEG), USEPA's cancer slope factors,USEPA's reference doses (RfD), and ATSDR's minimal risk levels (MRLs).

If someone is exposed, will they get sick?

Exposure does not always result in harmful health effects. The type and severity of health effectsthat occur in an individual from contact with a contaminant depend on the exposure concentration(how much), the frequency duration or both of an exposure (how long), the route or pathway ofexposure (breathing, eating, drinking, or skin contact), and the multiplicity of exposure(combination of contaminants). Once exposure occurs, characteristics such as age, sex, nutritionalstatus, genetics, life style, and health status of the exposed individual influence how the individualabsorbs, distributes, metabolizes, and excretes the contaminant. Together, these factors andcharacteristics determine the health effects that could occur as a result of exposure to acontaminant in the environment.

There is considerable uncertainty about the true level of exposure to environmental contamination.To account for this uncertainty and to be protective of public health, ATSDR scientists typicallyuse high-end, worst-case exposure level estimates as the basis for determining whether adversehealth effects are possible. These estimated exposure levels usually are much higher than those towhich people are really exposed. If the exposure levels indicate that adverse health effects arepossible, then a more detailed site-specific review of exposure combined with scientificinformation from the toxicological and epidemiological literature about the health effects fromexposure to hazardous substances is performed. Considering all of this weight-of-evidenceinformation, ATSDR makes a determination whether adverse health effects are likely.

More information about the ATSDR evaluation process can be found in ATSDR's Public Health Assessment Guidance Manual at http://www.atsdr.cdc.gov/HAC/HAGM or by contacting ATSDR at 1-888-42ATSDR (1-888-422-8737).


APPENDIX E: EXPOSURE EVALUATION METHODOLOGY AND ASSUMPTIONS

This appendix details the assumptions and calculations that ATSDR used to estimate potentialexposure levels from consumption of contaminated fish, eels, and snails and soil. To be protectiveand account for the uncertainty surrounding how representative the exposure factors are for theresidents of Mongmong, ATSDR used health-protective assumptions to estimate the reasonablemaximum exposure level. This estimate calculates a daily exposure dose in milligrams ofcontaminant per kilogram body weight (mg/kg/day). To remain protective of public health, it isintentionally protective and likely overestimates the amount of chemical exposure from eating fish,eels, and snails and contacting soil.

The PCBs were evaluated by adding the concentrations for Aroclors 1248, 1254, and 1260. The semivolatile compounds making up the dioxins were evaluated by multiplying each dioxin concentration by its toxic equivalency factor (TEF) based on its potency relative to 2,3,7,8 tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). The adjusted concentrations of dioxins were added together and evaluated as one total concentration, the 2,3,7,8-TCDD toxic equivalency (TEQ). Appendix C has more information about calculating the 2,3,7,8-TCDD TEQ.

We calculated an estimated dose for PCBs and dioxins using the mean value for each type of fish,eels, or snails sampled or for each soil area. For chemicals not detected, the concentration level wasgiven a value of zero. For calculating cancer risk estimates, ATSDR used USEPA's cancer slopefactor for oral doses and then compared those estimates to a risk level of 0.0001. The risk level of0.0001 (1/10,000) was used because it reflects realistic human exposures; however, risk levels aretheoretical and actual risks may be as low as zero. For screening non-cancer effects, the estimateddoses were compared to ATSDR's minimum risk level (MRL) for the corresponding chemical. TheMRL is derived from the lowest observed adverse effect level (LOAEL) identified in the scientificliterature by dividing the LOAEL by a safety factor to protect sensitive groups and account fordifferences between humans and animals in response to exposure. The scientific evidence on PCBsand dioxins was also reviewed to determine the likelihood of finding adverse health effects inchildren, pregnant women, and other adults.

Formulas Used to Calculate Potential Exposure Dose

The potential exposure doses for non-cancer health effects and cancer effects are calculated usingthe following equation:

Dose(mg/kg/day) equals (C times IR times EF times ED) divided by (BW times AT times AD)

Formula Used to Calculate Amount of Meals per Month

Meals/Month equals (Doses times BW times AT times AD times 30) divided by (C times EF times ED times M)

Dose=EPA's reference dose

Fish, Eels, and Snails Exposure Dose Assumptions

The Navy conducted a seafood consumption survey in Piti, Agat, and Santa Rita (US Navy 2002). The results indicated that the average person ate a meal size of 8.9 ounces (252 grams) of fish 8.4 times per month, or 2.5 ounces (70.5 grams) of fish per day. ATSDR used these values from the survey to calculate exposure dose. The Navy's seafood consumption survey did not collect information about the ingestion rates of children. So ATSDR estimated that a high-end child consumer eats half the amount of adults, or 1.25 ounces (35.25 grams) of fish per day. For the general U.S. population, the USEPA has estimated that on average people consume 20.1 grams/day for all fish and shellfish (EPA 1997b). For Native American subsistence populations, the 95th percentile per capita fish intake rate is estimated at 170 grams/day (Toy 1996). With these consumption comparisons, ATSDR believes that the consumption values used to calculate exposure doses are protective of human health. Table E-1 lists additional assumptions used in calculations.

Table E-1:

Fish, Eels, and Snails Exposure Dose Assumptions
Parameter Abbreviation Child Adult
Chemical Concentration C specific to location specific to location
Ingestion Rate IR 35.25 g/day 70.5 g/day
Exposure Frequency EF 365 days/year 365 days/year
Exposure Duration ED 10 years 40 years
Body Weight BW 15.3 kg 72 kg
Averaging Time AT 365 days 365 days
Averaging Duration Carcinogens AD 70 70
Averaging Duration Non-carcinogens AD ED ED
Average Meal Size M 0.126 kg 0.252 kg

Table E-2 is an example of calculated non-cancer effects doses for PCB exposure from eating fish, eels, and snails from the Agana Swamp and River.

Table E-2.

Estimated PCB Exposure Dose Levels from Eating Fish, Eels, and Snails from the Agana Swamp and River
Non-cancer effects
Type of fish Adult Dose (mg/kg/day) Child Dose (mg/kg/day) MRL (mg/kg/day) Average PCB conc. (mg/kg)
Apple snail 0.0000024 0.0000057 0.00002 0.0025
Tilapia fillet 0.00013 0.000048 0.00002 0.14
Catfish fillet 0.000021 0.00014 0.00002 0.021
Eel fillet 0.000058 0.00031 0.00002 0.059

These assumptions were also used to calculate the number of meals an adult or child could eat in a month without exceeding USEPA's health protective reference dose (RfD) (see Table 5).

Soil Exposure Dose Assumptions

ATSDR placed people into five groups based on age and relative body weight. The amount of soil each age group would ingest was intentionally overestimated. The groups are (1) infants age 6 months to 3 years exhibiting pica behavior by eating soil, (2) infants age 6 months to 3 years not exhibiting pica behavior, (3) young children age 3 to 12 years old, (4) teenagers age 12 to 18 years old, and (5) adults—including pregnant women and the elderly. Table E-3 lists additional assumptions used in the calculations. Pica children were evaluated for acute rather than long-term exposures because pica behavior generally involves ingestion of a large amount of soil during single day rather than smaller amounts over a longer period of time (Calabrese 1997).

Table E-3:

Soil Exposure Dose Assumptions
Parameter Pica Child 6 mos. to 3 years Non-pica Child 6 mos. to 3 years Child 3 to 12 years Teenager 12 to 18 years Adult
Chemical Concentration C specific to location specific to location specific to location specific to location specific to location
Ingestion Rate IR 1000 mg/day 100 mg/day 100 mg/day 100 mg/day 50 mg/day
Exposure Frequency EF 1 day 365 days/year 365 days/year 365 days/year 365 days/year
Exposure Duration ED 1 day 2.5 years 9 years 6 years 30 years
Body Weight BW 15.3 kg 15.3 kg 28 kg 50 kg 71.8 kg
Averaging Time AT 1 day 365 days/year 365 days/year 365 days/year 365 days/year
Averaging Duration Carcinogens AD NA* 2 years 9 years 6 years 70 years
Averaging Duration Non-carcinogens AD ED ED ED ED ED

*NA = Not applicable

Table E-4 is an example of calculated non-cancer effects doses for PCB exposure from accidentally ingesting soil while gardening or playing in the West Drainage area and residential area. Note that exposure dose for the West Drainage area represents past exposure because the 3.69 mg/kg average soil concentration is the preremediation concentration. Current exposure doses from soil are much lower with the postremediation average of 0.53 mg/kg in the West Drainage area.

Pica Child 6 mos. to 3 years

Table E-4.

Estimated PCB Exposure Dose Levels from Accidentally Ingesting Soil
While Gardening or Playing - Non-cancer effects
Location* Dose (mg/kg/day) MRL (mg/kg/day) Average PCB conc. (mg/kg)
Pica Child 6 mos. to 3 years Non-Pica Child 6 mos. to 3 years Child 3 to 12 years Teenager 12 to 18 years Adult
Residential Area 4.2 x 10-6 4.2 x 10-7 2.3 x 10-7 1.3 x 10-7 4.5 x 10-8 2.0 x 10-5 0.065
West Drainage Area 1.2 x 10-4 2.4 x 10-5 1.3 x 10-5 7.4 x 10-6 2.6 x 10-6 2.0 x 10-5 3.69

*See Figure 2


APPENDIX F: FREQUENTLY DISCUSSED HEALTH EFFECTS FROM PCB EXPOSURES

Skin Effects

Effects from overexposure in occupational settings, which are higher levels than generally seen inthe environment, include chloracne, hyperpigmentation of the nails and skin, and skin irritation.These symptoms generally disappear when PCB exposure stops (ATSDR 2000c).

Developmental Effects

There are no reports of structural birth defects in humans caused by PCB exposure. Several recentstudies suggest that children born to mothers who ate PCB-contaminated fish during theirpregnancies might have had an increased risk of developing subtle (i.e., not easily observable)nervous system delays (e.g., abnormal reflexes, motor immaturity, deficits in memory, learning, andIQ). In some cases, these delays persisted into adolescence, but in most cases they returned tonormal within the first 2 to 4 years. These effects were only seen when large populations werestudied and tended to be within the normal range of variation. The clinical relevance of theseeffects, particularly for individual children, is unknown. Other studies, however, did not find theseassociations, and any changes that were observed disappeared upon later study (ATSDR 2000c).

Cancers

Some human studies suggest that PCBs are carcinogenic—based on indications of cancer in areas such as the liver, biliary tract, intestines, and skin (ATSDR 2000c). Studies have shown that animals exposed to high levels of PCBs over their lifetimes developed liver and kidney tumors (ATSDR 2000c). Based on observed cancers in animals, the Department of Health and Human Services concluded that PCBs might reasonably be anticipated to be carcinogens (ATSDR 2000c). Both the U.S. Environmental Protection Agency and the International Agency for Research on Cancer have determined that PCBs are probably carcinogenic to humans (ATSDR 2000c). This designation means that a clear cause-and-effect relationship has not been established in humans, but there is sufficient evidence to take precautions about exposure to this chemical. ATSDR continues to support recommendations by health and regulatory agencies to reduce exposure to PCBs.


APPENDIX G: REPORTED HEALTH CONDITIONS IN MONGMONG RESIDENTS

During ATSDR's community meetings, people wanted more information on the following healthissues and whether they were related to PCB exposures from the Agana Power Plant.

  • Asthma
  • Leukemia
  • Lung Cancer
  • Parkinson's Disease
  • Stomach Cancer

ATSDR's evaluation found that none of these health concerns were related to PCB exposure. Information on the known associations for these health issues and other information is provided in the following fact sheets.

Click here to view Appendix G in PDF format (PDF, 343KB)



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