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The Wells G and H site encompasses two municipal wells located in Woburn, Massachusetts. The water drawn from these wells was used as a municipal water supply for the city of Woburn from 1964 to 1979. A Health Assessment was completed in 1989. This public health assessment addendum focuses on the indoor air monitoring studies conducted at the Wells G and H site since the completion of the Health Assessment in 1989. Three residences and a day care center were sampled to determine the extent of indoor air contamination due to volatilization of contaminants from the groundwater plume into the basements of the residences and the day care center. The sampling was conducted in July 1989, and in April and October 1991. The primary contaminants detected in indoor air were carbon tetrachloride, benzene, 1,2-dichloroethane, trichloroethylene, 1,1-dichloroethylene, methylene chloride, and chloroform.

Populations potentially exposed to indoor air contaminants from the study area include residents and workers in the area and workers and children at the day care center. The exposure pathway of potential concern is the inhalation of indoor air. Although individuals have been exposed to and are exposed to contaminants in the indoor air in the residences and day care center, adverse health effects are unlikely due to the low concentrations detected.

It is unlikely that the chemicals detected during these sampling investigations are site related. The concentrations measured were typical of concentrations seen in many studies of ambient or indoor air. The majority of the samples taken at three Woburn residences and the Puddle Duck Day Care center resulted in either non-detectable levels of contaminants or low levels of contaminants. The highest levels were detected consistently at the 6 Dewey Avenue residence, which stored a considerable amount of household products. Such products contain a variety of the compounds of concern associated with this investigation; therefore suggesting another potential source of contamination. The proximity of various industrial companies, including a printing press, may be a source of contamination for the indoor air of the Puddle Duck Day Care Center. Therefore, identifying the contaminated groundwater as the only source contributing to air concentrations in the basements, cannot be made with any certainty.

Based on the available information, the indoor air in the site vicinity represents no apparent public health hazard. However, the conclusions of this public health addendum do not change the original conclusions of the 1989 Public Health Assessment, which said that the Wells G and H site represents a public health hazard because of the risk to human health resulting from current and past exposure to hazardous substances, in the soil and municipal drinking water respectively, at concentrations that may result in adverse health effects.


A. Site Description and Reason for Addendum

This health assessment addendum evaluates the results of indoor air investigations conducted in response to concerns of volatile organic compounds volatilizing from contaminated groundwater originating from the Wells G and H site in Woburn, MA.

The Wells G and H National Priority List (NPL) site is located in Woburn, Middlesex County, Massachusetts about ten miles north of Boston (Figure A-1). Woburn Municipal Wells G and H were used from 1964 to 1979 to supplement Woburn drinking water supplies. The groundwater extracted from Wells G and H was found to be contaminated with volatile organic compounds in 1979 due to contaminated groundwater plumes originating from the Unifirst Corporation and the W.R. Grace Company; Wells G and H were subsequently shut down. Other sources of groundwater contamination are the Olympia Property, New England Plastics, and the Wildwood Conservation Corporation. The predominant groundwater contaminants are trichloroethylene (TCE), tetrachloroethylene (PCE), trans-1,2-dichloroethene (t-1,2-DCE), 1,1,1-trichloroethane (1,1,1-TCA), and vinyl chloride. For a complete description of the site and study area, refer to the previous Health Assessment located in Appendix D.

In the Health Assessment, the Massachusetts Department of Public Health (MDPH) and the Agency for Toxic Substances and Disease Registry (ATSDR) concluded that air quality determinations inside Dewey Street residences, the Unifirst Corporation, the W.R. Grace and Company and the West Cummings Park would be valuable to determine possible health risks from exposure to volatile organic compounds (VOCs). These recommendations were based on concern for the potential volatilization and migration of VOCs from groundwater into the basements of these buildings. To allay public concern, the U.S. Environmental Protection Agency (EPA) conducted an air investigation of three homes in the Dewey Avenue area to evaluate whether VOCs were in fact volatilizing from groundwater and infiltrating residential basements. Concurrent with this April 1989 investigation, ENSR Consulting and Engineering evaluated the indoor air of these same three homes. The results were presented in EPA's "Residential Indoor Air Sampling Results, Wells G and H Superfund Site, Woburn, Massachusetts," June 1989 and ENSR's "Woburn Indoor Air Monitoring Program," July 1989. In April and October 1991, investigations were conducted to obtain data that would determine whether emissions from the underlying contaminated groundwater were migrating inside the Puddle Duck Day Care Center located on Olympia Avenue adjacent to the Unifirst Corporation. The results of these investigations were reported in "Indoor Air Screening Survey Results, Puddle Duck Day Care Center, Wells G and H Superfund Site, Woburn, Massachusetts," April 1991 and "Indoor Air Survey II-Results, Puddle Duck Day Care Center, Wells G and H Superfund Site, Woburn, Massachusetts," November 1991.

B. Site Visit

On April 27, 1995, Jefferey Purvis, Chief of the Community Assessment Unit of the Bureau of Environmental Health Assessment visited the Wells G & H area to determine its current status and condition. The well field itself was easily accessed, although it was not clearly demarcated, and a no- trespassing sign was posted on the access road. The area was unfenced, and rolls of old fencing lay in the area along with piles of concrete piping. It did not appear that the site had recently been accessed for remediation or other purposes; however, discarded clothing, furniture, tires, and other debris indicated that area residents had visited the site at some point in the past.

The Puddle Duck Day Care Center was also included in this site visit. The day care center is located on Olympia Avenue in a 200-300 foot long building housing several small industrial companies. Abutting the day care center is the Miano Printing Service which includes an open loading dock with an active printing press; several other loading docks were located in this building, and a number of trucks were idling in the vicinity.

Excavation of all soils was completed at the Wildwood Conservation Corporation in 1994. Soil and sludge contaminated with VOCs, chlordane, and other pesticides were removed and incinerated off site. Pumping tests have also been conducted at Wildwood for the development of a soil vapor extraction system. Soil contamination exists at the Unifirst property, but not at W.R. Grace. Both Unifirst and New England Plastics are in the design stages of soil remediation. As of April 1995, both Unifirst Corporation and W.R. Grace and Co. have UV-oxidation systems in place to treat groundwater in area bedrock and shallow bedrock (DEP, 1995). Groundwater treatment systems will potentially be installed at the Wildwood, New England Plastics and Olympia properties (DEP, 1994).

C. Demographics, Land Use, and Natural Resource Use

The Wells G and H site is bordered by Interstate 95 to the north, Interstate 93 to the east, Cedar Street and Salem Street to the south, and the B & M Railroad to the west (Figure A-2). The 1990 U.S. Census indicated 35,943 individuals live within the City of Woburn. The population size decreased by 1.9% during the period 1980 to 1990.

Bordering the site to the east, south, and west are extensive residential developments. Substantial development of land was occurring near the site at the time of the release of the Health Assessment, especially for residences just south of the site. Within the site, some of the upland industrial properties could be converted to residential use in the future (ATSDR, 1989).

Currently, land use in the study area is similar to that described in the original Health Assessment. The site includes numerous existing light industrial and manufacturing facilities, as well as one small residential development and several isolated residences.

Scientists at the Massachusetts Institute of Technology are in the process of studying arsenic distribution in the Aberjona Watershed and its implications on the Wells G & H site. For detailed information on demographics, land use, and natural resource use, refer to the previous Health Assessment located in Appendix D. Since the completion of the previous health assessment, groundwater treatment systems have been installed at two of the source areas. Systems to address groundwater contamination at the three remaining source area properties have yet to be designed.

D. Health Outcome Data

Relevant health outcome data were obtained from the Massachusetts Cancer Registry for review in the 1989 Health Assessment. Cancer incidence data for the years 1982 - 1988 included types of cancer determined to be of concern based on the available scientific literature, and community health concerns. Analyses were made at the city and census tract levels. Population data (1990) were obtained from the Region I Office of the U.S. Census. No data were available regarding non-carcinogenic adverse health effects that may have occurred due to exposure to the contaminants detected. The evaluation of the health outcome data is presented in the section on Public Health Implications.


Community concerns about the Wells G and H site are evident. Numerous newspaper articles have reported alleged health impacts from the site and a high volume of correspondence has been received by state and federal regulatory and health officials. Community citizens established "For a Cleaner Environment" (FACE) in the early 1980's due to concern about a perceived elevation of childhood leukemia in Woburn and its possible relation to the contaminants released by Superfund sites in the area.

Topics identified as being of particular public health concern include the past, present, and future threat to public health due to potential exposure to site-related contaminants in soil, air, and groundwater. Citizens also expressed concern about adverse health effects including leukemia, adverse reproductive outcomes, and child health issues.

On July 29, 1994, in the Daily Times Chronicle, the MDPH invited public comments on the public health assessment addendum for the Wells G & H site. Upon review of this addendum, both the Massachusetts Department of Environmental Protection (MDEP) and the Remedial Project Manager for the EPA suggested clarification of the extent of groundwater contamination and treatment facilities in relation to the Wells G & H site. The document has been modified according to these comments. (See Appendix C for Comments).

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