PUBLIC HEALTH ASSESSMENT
WEST SITE/HOWS CORNER
PLYMOUTH, PENOBSCOT COUNTY, MAINE
- Based upon data and information reviewed in this Public Health Assessment, the Agency for
Toxic Substances and Disease Registry (ATSDR) concludes that the West Site/Hows Corner
National Priorities List Site represented a public health hazard in the past because of known
past exposures. Area residents were exposed to contaminated groundwater and workers and
others were exposed to on-site soils with elevated levels of contaminants. Direct exposure to
contaminated groundwater is believed to have stopped. Those residents with known
contamination of their potable water supplies were placed on an alternative water source and
later connected to the public water supplies. However, more recent sampling data seems to
indicate that the contaminated groundwater has migrated off the site. More sampling is
necessary to determine if the contamination could affect the potable water supplies of those
resident not using the public water system. The contaminants in the on-site soils were
remediated to cleanup levels and should no longer pose a threat to people who may become
exposed to them. Neither of these exposures is believed to still be occurring.
The site is currently an indeterminate public health hazard, because of the potential for the contamination of ambient air from substances evaporating from contaminated groundwater and springs and because of possible migration of contaminated groundwater off the site.
- ATSDR has provided a toxicological evaluation of contaminants reported to have been present
in contaminated residential drinking water wells. Assuming that tetrachloroethylene (PCE) is
carcinogenic to humans, then there is possibly a moderate increased risk of developing cancers
such as liver and kidney tumors for people exposed to the PCE at the maximum concentration
found for extensive periods of time. People with known well contamination have been given an
alternate water source since 1988.
- ATSDR has provided a toxicological evaluation of contaminants reported to have been present in contaminated on-site soils. Based upon that evaluation ATSDR believes that carcinogenic and non-carcinogenic health effects may be possible. Polychlorinated biphenyls (PCBs) may have caused chloracne, skin irritation, and hematological and immunological system effects. It may also have put people at a moderate increased risk of developing lymphoma, leukemia, and cancers of the liver and gastrointestinal systems.
Cease/Reduce Exposure Recommendations
Because of the potential for contamination of the ambient air by substances evaporating from affected groundwater and springs, a few representational areas should be sampled for site contaminants in the air or in soil gases.
Contaminated groundwater is believed to be migrating off of the site. Residents or businesses which have elected to continue to use their well for drinking or other domestic purposes, and who are concerned about the quality of their water, should contact the Maine Department of Environmental Protection (207-287-2651) for information about testing their water.
The Health Activities Recommendations Panel (HARP) is an ATSDR panel whose members evaluate hazardous waste sites and then determine the appropriate activities necessary to protect the public health. HARP evaluated the Hows Corner site and decided that ATSDR will work with the community to provide necessary information to the persons who may have been exposed to contaminated groundwater or soil. In addition, should air or soil gas sampling indicate that exposure to contaminated air could occur, ATSDR will evaluate the need for additional actions.
The public health action plan (PHAP) for the Hows Corner site in Plymouth, Maine, contains a description of actions which ATSDR representatives will take at and near the site. The PHAP is designed to ensure that this public health assessment not only identifies public health hazards, but also provides an action play for the mitigation and prevention of adverse human health effects resulting from exposure to hazardous substances in the environment.
ATSDR provided the residents of the city of Plymouth and surrounding communities the opportunity to comment on this public health assessment before final release. The public comment period was held from August 19, 1996 to September 25, 1996. ATSDR accepted comments until October 1, 1996. ATSDR did not receive any comment during this period.
ATSDR staff will work with the Maine Department of Environmental Protection and the United States Environmental Protection Agency to plan appropriate actions regarding the possible contamination of ambient air. Possible actions include a survey of homes in affected areas surrounding the site, and the sampling of ambient air or soil gases in or near a few homes. ATSDR will also help in the evaluation of results from any of these actions. ATSDR will evaluate data from sampling events which were not previously evaluated and make recommendations as appropriate.
ATSDR will monitor the extent of future community health concerns and future site activities. If needed, ATSDR will provide additional actions to help the community become more informed about how the site may affect their health.
Preparers of Report:
Dana M. Abouelnasr, MPH, Ph.D.
Déborah Boling, MPH
Environmental Health Scientist
Shan-Ching Tsai, Ph.D.
ATSDR Regional Representative:
Louise House, MA, RN, COHN
ATSDR Senior Regional Representative, Region I
- Agency for Toxic Substances and Disease Registry. Public Health Consultation: Evaluation of Soil Samples, Hows Corners site, Plymouth, Maine. Atlanta: US Department of Health and Human Services, Public Health Service, October 22,1990.
- Census of Population and Housing, 1990: Summary Tape File 1A (Maine) [machine-readable data files]. Prepared by the Bureau of the Census. Washington DC: The Bureau [producer and distributor], 1991.
- Weston Geophysical Corporation. Geotechnical Investigation, Plymouth, Maine Phase I - Site Assessment. September 1988.
- Weston Geophysical Corporation. Geotechnical Investigation, Phase II - Subsurface Investigations, Plymouth, Maine. March 1990.
- US Environmental Protection Agency. Memo from Dean Tagliaferro to Louise House, ATSDR, October 3, 1990.
- Agency for Toxic Substances and Disease Registry. Public Health Consultation for West Site/Hows Corners, Plymouth, Penobscot County, Maine. Atlanta: US Department of Health and Human Services, Public Health Service, February 21, 1991.
- US Environmental Protection Agency. West Site/Hows Corner HRS Documentation, January, 1995.
- Agency for Toxic Substances and Disease Registry. Agency Record of Activity. Conversation with Terrence Connelly, EPA RPM, regarding his comments on the initial release public health assessment for the Hows Corner site. October 1, 1996.
- Agency for Toxic Substances and Disease Registry. Public health assessment guidance manual. Atlanta: ATSDR, March 1992; DHHS, (PHS).
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,1-Dichloroethene. (update) Atlanta: ATSDR, May 1994, DHHS, (PHS).
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polychlorinated biphenyls. (update) Atlanta: ATSDR, August 1995a, DHHS, (PHS).
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Tetrachloroethylene. (update) Atlanta: ATSDR, August 1995b; DHHS, (PHS).
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,1,1-Trichloroethane. (update) Atlanta: ATSDR, August 1995c; DHHS, (PHS).
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Trichloroethylene. (update) Atlanta: ATSDR, August 1995d; DHHS, (PHS).
- Hazardous Substance Database. Tomes Integrated Index. CD-ROM, Vol 25. New York:Micromedix, 1995.
- Screening values are concentrations of hazardous substances in soil, air, or water, below
which no adverse health effects are expected to occur. Please see Appendix A for more
The EPA consulted with ATSDR in 1991 when the clean-up levels for these three substances were defined. ATSDR concurred with the EPA that these levels were protective of the public health. No adverse health effects were expected to occur to people exposed to the soils remaining at the West Site/Hows Corner site (6).
- A monitoring well is a well which has been constructed only for the purpose of studying the flow and quality of groundwater.
- The provision of bottled drinking water and the placement of water filtration systems on residential wells is assumed to have occurred prior to December, 1988. The data in Table 4 summarize the sampling that was done prior to this date.
- After inhaling particles larger than 10 microns (10 millionths of a meter) such as airborne soil or dust particles, the respiratory system is able to cleanse itself of the particles, which are then disposed of down the throat. The end result is that a person may swallow small amounts of soil.
- The site began operations in 1960. It is assumed that ten years passed before the on-site groundwater became contaminated and then migrated to the residential wells. Residents could then have been exposed to contaminants beginning in 1970.
- The total number of people who have been affected by known exposures at this site is estimated to be 140; 90 people or fewer could have been exposed to contaminated soils on the site, and approximately 50 people were exposed to contaminated groundwater in residential wells in 1988.
- All of the information in this section regarding polychlorinated biphenyls is from the ATSDR Toxicological Profile for Polychlorinated Biphenyls (11).
- All of the information in this section regarding tetrachlorobenzenes is from the Hazardous Substances Database (15).
- All of the information in this section regarding 1,1-Dichloroethene is from the ATSDR Toxicological Profile for 1,1-Dichloroethene (10).
- All of the information in this section regarding tetrachloroethene is from the ATSDR Toxicological Profile for Tetrachloroethylene (12).
- All of the information in this section regarding 1,1,1-Trichloroethane is from the ATSDR Toxicological Profile for 1,1,1-Trichloroethane (13).
- All of the information in this section regarding trichloroethene is from the ATSDR Toxicological Profile for Trichloroethylene (14).