Skip directly to search Skip directly to A to Z list Skip directly to site content

HEALTH CONSULTATION

KITSAP COUNTY - BAINBRIDGE ISLAND DUMP
BAINBRIDGE, KITSAP COUNTY, WASHINGTON


APPENDIX A: EXPOSURE ASSUMPTIONS

For this health consultation, it is assumed that a completed exposure pathway exists and residents were exposed 350 days per year, for thirty years to the maximum detected chemical concentrations which exceeded a screening value (i.e., those contaminants highlighted in Table 1). This exposure duration accounts for potential past and future exposures, as well as current exposure. Both adult and child through adult exposure scenarios were evaluated. Adults were assumed to consume 2 liters of water per day, and children were assumed to consume 1 liter of water per day until 5 years of age and 2 liters of water per day for the remaining 25 years. Children were assumed to be exposed for 5 years at a 16 kilogram (kg) body weight, for 10 years at a 40 kg body weight, and for 15 years at a 70 kg body weight. Children and adults were assumed to be exposed to VOCs through ingestion (drinking) and non-ingestion (inhalation and dermal contact) routes. Non-ingestion exposures are assumed to occur during household activities such as cooking, bathing, and dishwashing.


APPENDIX B: EXPOSURE FORMULAS

It is assumed that non-ingestion (inhalation and dermal) exposures are equal to exposures through ingestion.

Exposure dose = ((C x IR x EF x ED)/BW x AT)) x 2

Excess cancer risk = Exposure dose x CSF

where:
C = concentration of contaminant (µg/l)
IR = Ingestion rate (liters of water/day)
EF = Exposure frequency (days/year)
ED = exposure duration (total # of years in exposure period)
BW = body weight
AT = averaging time (70 years x 365 days/year)
CSF = Cancer slope factor (Estimates the excess upperbound lifetime probability of an individual developing cancer from an exposure)


TABLE 1

CONTAMINANT RANGES AND MAXIMUM DETECTIONS DOMESTIC WATER WELLS (AS OF MARCH 1998)
Chemical Name Concentration Range (µg/l) Carcinogenic Screening Value (µg/l) Non-carcinogenic Screening Value (µg/l) Well ID Well Type Number of Residences Served
1,1-Dichloroethane ND - 0.25

NA

800 (MTCA B) BOW37 Group B 6
1,1,1-Trichloroethane ND - 0.2 (J) NA 200 (MCL/LTHA) BOW52 Private 1
1,2,4-TMB (pseudocumene) ND - 0.3 NA NA BOW73 Group B 2
Acenaphthene ND - 1.9 NA 600 (Child RMEG) BOW31A Private 1
Acetone ND - 13 NA 1,000 (child RMEG) BOW52 Private 1 + school
Arsenic 10.7 - 26.2 0.02 (CREG) 3 (child chronic EMEG) BOW31A Private 1
Bis (2-ethylhexylphthalate) 2.7 3 (CREG) 200 (child RMEG) BOW52 Private 1
Bromoform ND - 0.1 (J) 4 (CREG) 200 (child RMEG) BOW04 Private 2
2-Butanone (MEK) ND - 6.9 NA 6,000 (child RMEG) BOW52 Private 1
Carbon disulfide ND - 0.4 NA 1,000 (child RMEG) BOW15 Private 1
Chloroethane ND - 0.2 NA NA BOW37 Group B 6
Chloroform ND - 2.7 6 (CREG) 100 (child chronic EMEG) BOW47 Private 2
Chloromethane ND - 0.2 (J) 3 (LTHA) 3 (LTHA) BOW45 Private 1
Chromium ND - 9 (B) NA 50 (child RMEG) BOW64 Group A 1 + school
Dichlorodifluromethane 1.1 - 3.95 NA 2,000 (RMEG) BOW37 Group B 6
Diethylphthalate ND - 1.7 NA 8,000 (child RMEG) BOW31A Private 1
Lead 1 (B) - 67 NA 15 (EPA Action level) BOW64 Group A 1 + school
Manganese 589 NA 50 (RMEG) BOW12 Private 1
Methylmethacrolate 0.5 NA 640 (MTCA B) BOW01 Group B 8
Methylene chloride 0.3 5 (CREG) 600 (child chronic EMEG) BOW33 Private 1
Naphthalene ND - 0.4 (J) NA 200 (child inter. EMEG) BOW35 Private 1
Toluene ND - 0.4 NA 200 (child inter. EMEG) BOW73 Group B 2
1,2,4-Trichlorobenzene ND - 0.1 (J) NA 70 (LTHA) BOW35 Private 1
Trichlorofluromethane ND - 0.9 NA 3,000 (child RMEG) BOW56 Group B 4
Vinyl chloride 0.3 - 0.77 NA 0.2 (child chronic EMEG) BOW37 Group B 6
Zinc 398 - 430 NA 3,000 (child chronic EMEG) BOW01 Group B 8

µg/l = micrograms of chemical per liter of water (equals one part per billion).
RMEG = ATSDR's Reference Dose Media Evaluation Guide
MTCA B = WA Model Toxics Control Act Method B groundwater cleanup level
NA = Not available
MCL = Federal and state drinking water standard
CREG = ATSDR's Cancer Risk Evaluation Guide
LTHA = EPA's Lifetime Health Advisory for Drinking Water
EMEG = ATSDR's Environmental Media Evaluation Guide
EPA Action Level = EPA's action level for lead in drinking water
ND = not detected
J = estimated value between the calculated detection limit and reporting limit
B = estimated value less than the contract required detection limit, but greater than or equal to the method detection limit/instrument detection limit
bolded compounds = compounds exceeding an ATSDR screening value which required further evaluation


REFERENCES

  1. Draft Remedial Investigation Report, Bainbridge Island Landfill, August 25, 1997. Kitsap County Department of Public Works, Solid Waste Division.

  2. Bainbridge Island Landfill site groundwater and domestic well sampling database (9/96-3/98).

  3. Site visits, Bainbridge Island Landfill, April 24 and September 17, 1998.

  4. Bainbridge Island Landfill Site, Public Groundwater Supplies, Kitsap County, WA., EPA Geographic Information Query System (Version 97.1.8), March 24, 1998.

  5. Integrated Exposure Uptake Biokinetic Model (IEUBK-Version 0.99D), United States Environmental Protection Agency.

  6. Integrated Risk Information System (IRIS), April 1998.

  7. ATSDR Health Consultation Procedures, Agency for Toxic Substances and Disease Registry, May 1995.

  8. Toxicological Profile for Vinyl Chloride, U.S. Department of Health and Human Services, Public Health Service, ATSDR,

  9. Toxicological Profile for Manganese (Draft for Public Comment/Update) , U.S. Department of Health and Human Services, Public Health Service, ATSDR, September 1997.

  10. Toxicological Profile for Lead, U.S. Department of Health and Human Services, Public Health Service, ATSDR,

  11. Toxicological Profile for Arsenic, U.S. Department of Health and Human Services, Public Health Service, ATSDR,

  12. Micromedex, Environmental Health & Safety Series, TOMES Plus,

  13. Conversations with Barbara Trejo, Washington State Department of Ecology and Meliss Maxfield, Bremerton-Kitsap County Health District.

  14. Centers for Disease Control and Prevention, National Center for Environmental Health. Childhood Lead Poisoning Prevention. Screening young children for lead poisoning: Guidance for State and Local Public Health Officials, November 1997.

  15. American Cancer Society Homepage: 1998 Cancer statistics.

DEFINITIONS

EMEG: ATSDR's Environmental Media Evaluation Guide. A concentration in air, soil, or water (or other environmental media), which is derived from ATSDR's MRL, and below which adverse non-cancer health effects are not expected to occur. Separate EMEGs can be derived to account for acute, intermediate, or chronic exposure durations.

RMEG: ATSDR's Reference Dose Media Evaluation Guide. A concentration in air, soil, or water (or other environmental media), which is derived from EPA's RfD, and below which adverse non-cancer health effects are not expected to occur. RMEGs account only for chronic exposure.

MRL: ATSDR's Minimal Risk Level. An estimate of daily human exposure to a dose of chemical that is likely to be without an appreciable risk of adverse noncancerous health effects over a specified duration of exposure. MRLs are derived when reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration via a given route of exposure. MRLs can be derived for acute, intermediate, and chronic duration exposures by the inhalation and oral routes.

CREG: ATSDR's Cancer Risk Evaluation Guide. A concentration in air, water, or soil (or other environmental media), which is derived from EPA's cancer slope factor and carcinogenic risk of 10E-6 for oral exposure. It is the concentration that would be expected to cause no more than one excess cancer in a million persons exposed over a lifetime.

CHRONIC RfD: An estimate (with uncertainty spanning perhaps an order of magnitude) of the daily exposure level of the human population, including sensitive subpopulations, to a potential hazard that is likely to be without an appreciable risk of deleterious effects (non-cancer) during a lifetime. It was developed to be protective for long-term exposure to a compound (7 years or longer).

CANCER SLOPE FACTOR: A plausible upperbound estimate of the probability of a response per unit intake of a chemical over a lifetime. The slope factor is used to estimate an upperbound probability of an individual developing cancer as a result of a lifetime of exposure to a particular level of a potential carcinogen.

LOAEL: Lowest Observed Adverse Effect Level. LOAEL's have been classified into "less serious" or "serious" effects. In dose-response experiments, the lowest exposure level at which there are statistically or biologically significant increases in the frequency or severity of adverse effects between the exposed population and its appropriate control.

NOAEL: No Observed Adverse Effect Level. The dose of a chemical at which there were no statistically or biologically significant increases in frequency or severity of adverse effects seen between the exposed population and its appropriate control. Effects may be observed at this dose, but were judged not to be "adverse".

MCL: Federal Maximum Contaminant Level. A drinking water regulation established by the Safe Drinking Water Act. It is the maximum permissible concentration of a contaminant in water that is delivered to the free-flowing outlet of the ultimate user of a public water system. MCLs are enforceable standards.

CARCINOGEN: Any substance that can cause or contribute to the production of cancer.

CONTAMINANT: Any substance or material that enters a system (the environment, human body, food, etc.) where it is not normally found.

MONITORING WELLS: Wells developed to collect groundwater samples for the purpose of physical, chemical, or biological analysis to determine the amounts, types, and distribution of contaminants.

PLUME: An area of chemicals in a given media, such as groundwater

REMEDIAL INVESTIGATION: A study designed to collect the data necessary to determine the nature and extent of contamination at a site.

COMPARISON VALUE: A concentration used to select contaminants of concern at hazardous waste sites that are further evaluated in the health assessment process. The terms comparison value and screening level are often used synonymously.

CLHA: Child Long-Term Health Advisory

MTCA: Model Toxics Control Act. Washington States hazardous waste cleanup law.

MCLG: Maximum Contaminant Level Goal.



Table of Contents

  
 
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #