Background Information on Public Health Questions

Public Wells Contaminated
In 1978 two Acton town wells were found to be contaminated with organic compounds. (Contamination was later found to have come from a nearby industrial site, now designated as the WR Grace Superfund Site.) These public wells, Assabet I and Assabet II, had been in operation since the early 1970’s, and in 1978 supplied 40% of the town’s drinking water. Contaminants included : Ethylbenzene, 1,1-Dichloroethylene (also known as DCE or VDC), Benzene, 1,1,1-Trichloroethane (TCA), Trichloroethylene (TCE), Methylene Chloride, Toluene, and Chlorobenzene.

Board of Health Forms “Health Risk Subcommittee”
In response to residents concerns about past exposure to contaminants in drinking water, the Acton Board of Health formed a “Health Risk Subcommittee”. This subcommittee enlisted the aid of experts in the field, including epidemiologists: Dr. David Ozonoff, Dr. Daniel Wartenberg, and Dr. Stephen Lagakos, and the then head of the MA Cancer Registry, Richard Clapp. Bailus Walker, Jr., Commissioner of The MA Department of Public Health wrote to Acton Health Director, Steve Calichman, in December 1985: “We agree that some of the contaminants are quite toxic and are potential carcinogens. The Department [MA Department of Public Health] will be pleased to work with you and your office in designing a surveillance system….We look forward to collaborating with you.”

1988: Health Study Proposed, to MA DEQE
In 1988, on behalf of the Acton Board of Health three epidemiologists, Drs. Wartenberg, Ozonoff, and Lagakos submitted a proposal to the Massachusetts Department of Environmental Quality Engineering. The proposed study, entitled “A Surveillance and Investigation Program to Assess the Health Status of Residents of Acton, MA”, included development of a computer model to “reconstruct flows from the contaminated wells over time to evaluate which residences got the contaminated water and how much they got. ….This information would be input to the epidemiological evaluations.”

DEQE Director Carol Rowan West responded to the proposal: “…funding is not available. Our present research budget has been reduced given the fiscal problems of the Commonwealth.”

Town Meeting Funds Study
The Board of Health subcommittee subsequently obtained funding from the Town of Acton via a warrant article, and The John Snow Institute, Center for Environmental Health Studies (JSI), carried out a “Town of Acton Health Surveillance”. (See description of JSI study by ATSDR below.)

1992 ATSDR Documents
The Agency for Toxic Substances and Disease Registry (ATSDR) prepared preliminary “Public Health Assessment—Initial Release (PHA-IR)” and “— Public Comment Release (PHA-PCR)” documents in 1992.

These reports summarized contaminant levels found in the Acton public drinking water wells, Assabet I and Assabet II, as well as in soils, sludge, and groundwater at the WR Grace Superfund Site. The ATSDR documents also included cancer incidence rates for bladder cancer, brain cancer, kidney cancer, leukemia, liver cancer, lung cancer, pancreatic cancer, and stomach cancer for the years 1982-1988 in census tracts 3631.01 in Acton, and 3612 in Concord, MA. When compared to statewide rates significantly elevated rates were only found for brain cancer in women in Concord. Colorectal cancer incidence rates were not included in the census tract data presented in the ATSDR reports.

The ATSDR reports also discussed an early 1990’s health study conducted by the John Snow Institute, (JSI), Center for Environmental Health Studies for the town of Acton, to assess the public health impact from potential exposure to contaminated drinking water.

According to the ATSDR 1992 report (PHA–PCR):

(Begin quotation from ATSDR report)

“JSI conducted a descriptive epidemiological study in Acton which involved comparison of cancer cases (incidence) and deaths from cancer (mortality), incidents of low birth weights and fetal deaths in Acton to expected numbers for Massachusetts as a whole.”

“JSI assessed cancer mortality rates for bladder, liver, [and] colorectal cancers and leukemia between 1969 and 1988. The overall cancer mortality rate in Acton was lower than the Commonwealth’s rate except for the 1984-1986 time period. In addition, JSI determined that the rates in Acton do not suggest a definite increase in any specific cancer. Cancer incidence data indicate a statistically significant excess of colorectal cancer among males and bladder cancer among females for the 1982-1986 time period. Since that review, JSI received 1987 to 1988 cancer incidence data which suggest that the rates for colorectal and bladder cancer for both sexes were below the Commonwealth’s rates.”

“Preliminary work conducted by JSI determined that the occurrence of low birth weights (less[than] 2500 grams) was slightly elevated in the time period between 1975-1979 (during the expected time of exposure) when compared to a later time period, 1980-1984. More recent findings suggest that the rate of low birth weights in Acton is not high.” [Definition of high??] “Additional work is in process to verify the most recent findings and to account for a number of confounding factors.” [confounding factors?]

“JSI reviewed state fetal death records (deaths which occurred after 20 weeks gestation). In comparing contamination period and post contamination fetal deaths to the Commonwealth’s rates, JSI found no association between different time periods which would indicate an effect of exposure to contaminated water. Distance from residence to Assabet Wells One and Two were plotted and no association was found between residence and proximity to these wells.”

“It was difficult for the author [author of ATSDR Report?] to assess the findings of this study because of the number of assumptions that needed to be made due to the inherent limitations in the data.”

“(1) In looking at the rates in Acton it is assumed all residents were exposed. Approximately 40% of the community received water from these wells, however, specific consumers of water from Assabet Wells One and Two cannot be identified.

(2) Rates were not compared to individual doses. This cannot be done because, in addition to not knowing who the actual consumers were, the duration of exposure and the concentration an individual ingested from tap water are unknown. The maximum time period of exposure is the time period the wells were opened from 1970 to 1978, an assumption can be made that the concentration detected at the time of closure is representative of the concentration in the wells between 1970 and 1978.

(3) Sufficient time may not have elapsed to allow cancer to develop. Some types of cancer take longer than 10 years to develop.”

(End quotation from ATSDR report)

Correspondence from the John Snow Institute, (July 18, 1991), echoes point number three made in the ATSDR report. Terry Greene from JSI wrote: “…it is important to keep an eye on the data as it arises over time in light of the long latency period between exposure to carcinogens and the actual development of cancer.”

JSI also wrote that they requested data from the MA Cancer registry on “…non Hodgkins lymphoma, and Hodgkins disease, as these cancers are sometimes associated with exposure to carcinogens.”

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