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PUBLIC HEALTH ASSESSMENT

BERTRAND CREEK AREA PROPERTIES
(a/k/a NORTH WHATCOM COUNTY GROUNDWATER CONTAMINATION)
LYNDEN, WHATCOM COUNTY, WASHINGTON


CONCLUSIONS

1) A public health hazard exists for residents exposed to pesticides found in drinking water wells in the north Whatcom County area. Ingestion of drinking water and inhalation of vapors during showering are the primary routes of exposure. Exposure to these pesticides at levels above respective MCLs can pose a moderate to low increase in cancer risk over many years of exposure. In addition, the presence of EDB or multiple pesticides in drinking water at levels below respective MCLs will also carry some cancer risk. These estimates of cancer risk are based on animal experiments involving doses well in excess of anything experienced by north Whatcom County residents. These pesticides have not been shown to cause cancer in humans although studies of human populations are limited.

Non-cancer adverse health effects are not anticipated to result from exposure to the levels of these pesticides found in north Whatcom County groundwater. MCLs for these pesticides appear to be protective against non-cancer endpoints.

2) A public health hazard exists for pregnant women and bottle-fed infants exposed to nitrate in drinking water at levels above the MCL. While this risk appears to be small, current data examining adverse birth outcomes and methemoglobinemia suggest that some risk exists at levels approaching 20 ppm. Further investigation of the health risks associated with nitrate in drinking water is warranted.

3) No apparent public health hazard exists for migrant farm workers exposed to pesticides in drinking water. Only very low levels of 1,2-DCP were detected in two of seven wells during the most recent sampling round while all other pesticides of concern were not detected. Non-cancer health effects are not expected and cancer risk is not considered significant at current levels of 1,2-DCP in these wells. Consistent with other wells in the area, levels of 1,2-DCP appear to be declining in these two migrant camp wells. The past presence of EDB in the Ehlers camp well did represent a low to very low cancer risk for long-term exposure.

4) Nitrate has consistently been detected at or above the MCL in many of the migrant camp wells and therefore, poses a hazard to pregnant women and bottle-fed infants. The additional exposure of migrant farm workers to pesticides in soil and indoor dust is also cause for concern. While these pathways were not quantified in this health assessment, they are a potential source of pesticide exposure.

5) No apparent public health hazard exists for persons exposed to mixtures of pesticides and nitrate in drinking water at or below respective MCLs. A recently published long-term animal study suggests that nitrate present with very low levels of aldicarb and atrazine could have subtle effects on the immune system. While these pesticides are not generally found in north Whatcom County groundwater, this study is important mainly due to the fact that effects were seen at environmentally relevant doses. Interactions between nitrate and pesticides commonly found in groundwater need to be examined more thoroughly in light of these data.


RECOMMENDATIONS

1) Residents using drinking water wells contaminated with pesticides above respective MCLs should take steps to reduce both ingestion and inhalation exposure. In addition, residents using domestic water supplies contaminated with any detectable levels of EDB or multiple pesticides should consider reducing exposure.

  • Effective remedial measures include an alternate water source, drinking bottled water, increasing ventilation while showering/bathing, installing a carbon filtration device on shower-heads or installing a point-of-entry water treatment system.

2) Pregnant women and infants should not drink water containing nitrate at or above the MCL of 10 ppm. Other domestic uses of nitrate contaminated water are not considered to be a health hazard.

  • Effective remedial measures include an alternate water source, drinking bottled water and installing an appropriate treatment system for your drinking water.

3) Residents using drinking water wells contaminated with nitrate at or above the MCL and detectable levels of pesticides should consider steps to reduce both ingestion and inhalation exposure.

  • Effective remedial measures include an alternate water source, drinking bottled water, increasing ventilation while showering/bathing, installing a carbon filtration device on shower-heads and installing an appropriate treatment system for your drinking water.

4) Steps should be taken to reduce the potential for combined exposure of migrant farm workers to pesticides and nitrate in drinking water and pesticides in soil and indoor dust.

  • Annual sampling and analysis for 1,2-DCP should continue at those migrant camp wells that contain 1,2-DCP until decreasing trends are established. DOH will evaluate results of this testing. Nitrate sampling of these wells should adhere to current state and federal regulations.
  • Growers should ensure that their workers observe proper re-entry times when working in fields applied with pesticides. Re-entry time information is provided on the pesticide label.

  • Farm workers should take steps to reduce the amount of soil tracked inside the home from pesticide treated fields. Effective measures include removing work clothes and boots before entering the main living areas of the home and keeping pets outside the home and/or away from pesticide treated fields.

5) Residents living in areas of concern who have not had their wells tested should consider testing for EDB, 1,2-DCP, 1,2,3-TCP, DBCP and nitrate. Areas of concern include Study Areas A and B (see Figure 2) and any other agricultural areas with historical use of soil fumigants.

  • WCHHS has information on past and present agricultural land use as well as information on certified laboratories that test for pesticides and nitrate. WCHHS can be contacted at 360-676-6724. Ecology is currently evaluating groundwater contamination in the north Whatcom County area and may conduct further testing of private drinking wells.

6) DOH and ATSDR should pursue opportunities to examine the relationship between exposure to nitrate in drinking water and adverse health effects, specifically, methemoglobinemia in infants and adverse birth outcomes.

7) DOH and ATSDR should pursue opportunities to study the potential for adverse health effects, specifically on the immune system, from exposure to mixtures of nitrate and pesticides in drinking water.

8) WCHHS should continue to provide input to county and local planning departments to ensure that no new drinking water wells are located in contaminated areas. In addition, WCHHS should take an active role in developing strategies to reduce the potential for further contamination of the Sumas-Blaine aquifer.

  • The water quality database compiled by WCHHS for the north Whatcom County area should provide an excellent resource with which to make informed planning decisions with regard to reducing the potential for exposure to contaminants in groundwater.

PUBLIC HEALTH ACTION PLAN

The Public Health Action Plan (PHAP) for the Whatcom County Groundwater site is outlined below. The purpose of the PHAP is to ensure that this health assessment not only identifies public health hazards, but also provides a plan of action designed to prevent or mitigate adverse human health effects resulting from exposure to hazardous substances in the environment. Included is a commitment on the part of ATSDR and DOH to ensure that these actions are taken.

Actions Taken:

The Washington State Department of Ecology (Ecology) is currently providing bottled water and carbon filtration devices to homes with contamination at or above the MCL.

The Washington State Department of Health (DOH) has evaluated potential links between elevated leukemia rates in north Whatcom County and pesticides in drinking water. The results of this evaluation were presented at a public meeting on July 19, 1999.

The Environmental Protection Agency (EPA) conducted a Site Investigation of the north Whatcom County area in response to a petition expressing concern over possible source areas of pesticide groundwater contamination.

The Agency for Toxic Substances and Disease Registry (ATSDR) conducted an exposure investigation to determine the potential for inhalation of pesticides that volatilize from water during a shower.

DOH conducted state-wide testing of drinking water wells serving migrant farm worker facilities in the summer and fall of 1999.

DOH held an open house on March 30, 1999, to hear community health concerns related to groundwater contamination in the north Whatcom County area.

A joint public meeting organized by Ecology and DOH was held on October 20, 1999, to present the findings of this health assessment and the evaluation of remedial alternatives for contaminated wells.

Several fact sheets and consultations have been distributed to affected residents by Whatcom County Health and Human Services (WCHHS) and other agencies, providing information relative to drinking water contaminants, potential health effects and mitigative actions.

Actions Planned:

Ecology will propose long-term solutions for domestic water contaminated with EDB and 1,2-DCP for residences in the Bertrand Creek study area based on an evaluation of available options, including alternative sources, filtration and bottled water. A companion decision-making tool is being developed that may assist in assessing cost effective solutions for other similar contaminants.

ATSDR is considering a pilot study using mailed questionnaires or medical record review along with existing water supply sampling data to evaluate the risk of spontaneous abortion relative to exposure to nitrates in drinking water. This pilot would determine the feasibility of a retrospective approach to investigating this health risk, and of conducting a larger case-control study.

DOH is evaluating the feasibility of a targeted surveillance project that will help determine the incidence of methemoglobinemia in infants and its relationship to nitrate levels in drinking water. The project would require collaboration with local health departments. The WCHHS has agreed to assist DOH in such efforts.

WCHHS will continue to work with county and local planning departments to ensure that no new residential drinking water wells are located in areas of groundwater contamination.


PREPARER OF REPORT

Robert M. Duff
Office of Environmental Health Assessments
Washington State Department of Health


REFERENCES

1. Washington State Department of Social and Health Services. Results and Implications of the Investigation of Ethylene Dibromide in Ground Water in Western Washington. February 1995.

2. United States Department of Agriculture. 1997 Census of Agriculture, County Profile, Whatcom, Washington.

3. Whatcom County Health and Humans Services. June 10, 1999. Letter and maps from Anne Marie Karlberg to Robert Duff (WA DOH).

4. United States Department of Commerce. Landview® III. Environmental Mapping Software.

5. Washington State Department of Ecology. DRAFT 1998 Site Investigation Bertrand Creek & Meadowdale Areas, Whatcom County, Washington. June 1999.

6. Washington State Department of Ecology. Washington State Agricultural Pilot Study. November 1990. Publication No.. 98-46

7. Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,2-Dibromo-3-Chloropropane. September 1992.

8. Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,2,3-Trichloropropane. September 1992.

9. Washington State Department of Ecology. Sumas-Blaine Surficial Aquifer Nitrate Characterization. May 1998. Publication No. 98-310

10. Black and Veatch. Phase I Investigation: Ethylene Dibromide Sites, Whatcom County. Prepared for the Washington State Department of Ecology. June 11, 1986.

11. Mayer RJ, Lacher TE, Elkins NR and Thorn CJ. Temporal variation of ethylene dibromide (EDB) in an unconfined Aquifer, Whatcom County, Washington, USA: A twenty-seven month study. Bull. Environ. Contam. Toxicol. (1991) 47:368-373.

12. Whatcom County Health and Human Services. LENS Groundwater Study: Final Report. Prepared for the Washington State Department of Ecology. December 15, 1993.

13. Washington State Department of Health. An Evaluation of Nitrate and Organic Chemical Contamination in Selected Drinking Water Wells in Central North Whatcom County: Summary report. June 1998.

14. Roy F. Weston, Inc. Bertrand Creek Properties: Site Investigation Report, Lynden, Washington. Prepared for the U.S. Environmental Protection Agency, Region 10. March 1999.

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16. Agency for Toxic Substance and Disease Registry. Chemical Specific Consultation for Ethylene Dibromide and Dichloropropane. July 31, 1998.

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27. National Research Council. Nitrate and Nitrite in Drinking Water. National Academy Press, Washington D.C. 1995.

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32. Germolec DR, Yang RS, Ackermann MF, Rosenthal GJ, Boorman GA, Blair P and Luster MI. Toxicology studies of a chemical mixture of 25 groundwater contaminants: II. Immunosupression in B6C3F1 mice. Fundam. Appl. Toxicol. (1989) 13:377-387.

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35. Porter WP, Jaeger JW and Carlson IH. Endocrine, immune, and behavioral effects of aldicarb (carbamate), atrazine (triazine) and nitrate (fertilizer) mixtures at groundwater concentrations. Toxicol. Ind. Health. (1999) 15:133-150.

36. Loewenherz C, Fenske RA, Simcox NJ, Bellamy G and Kalman D. Biological monitoring of organophosphorous pesticide exposure among children of agricultural workers in central Washington State. Envrion. Health Perspect. (1997) 105:1344-1353.

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