REFERENCES
In response to a citizen's complaint, the Maine Department of Environmental Protection (DEP) first inspected the site in September 1978. As a result of the inspection, BIW was informed of the violations and discussed the disposal activities with DEP. In 1979, BIW submitted and received approval for an Operating Plan to handle the materials at the site. DEP's initial concern about this site was the potential threat to public health that may be present due to the company's methods of disposal, the variety of wastes, and the proximity of the site to the Tarbox Hill neighborhood [1].
In 1981, DEP approved the disposal of asbestos on the site; and in June 1986, DEP approved the closure of the asbestos disposal area on the site. The closure plan included the installation of six monitoring wells and the capping of the western portion of the site. The landfill stopped receiving all liquid waste from BIW in 1979 and the disposal of all waste on the site ceased in 1985. After 1985, all of the BIW's solid waste was disposed of at the Bath landfill and all the liquid waste was manifested and transported to a licensed disposal facility [3].
The Maine DEP collected residential private drinking water well samples in the Tarbox Hill neighborhood from 1978 until 1988. In September 1986, analysis of the private drinking water well samples confirmed the presence of volatile organic compounds (VOCs) and metals at levels that exceeded the maximum contaminant levels (MCLs). At that time, DEP recommended that public water lines be installed in the neighborhood and the process was completed in the summer of 1987. The decision to recommend that public water lines be installed in the neighborhood was based upon a Preliminary Assessment that DEP conducted of the site in 1981, studies of the site's hydrology and geology, information requested from the owner and from BIW Corporation, and the sampling data acquired.
As part of the 1981 Preliminary Assessment of the site, DEP identified the need for further groundwater sampling through monitoring wells. The monitoring wells were installed in August 1986 and have since been monitored quarterly. The DEP started collecting surface water and soil samples in 1984. The samples identified metals, solvents, hydrocarbons, coliform bacteria, chlorides, sulfates, and polychlorinated byphenyls (PCBs) in these media. At that time the BIW proposed surface clean-up of the site. In 1987, BIW submitted the clean-up plan for the site; the plan addressed the removal of surface wastes, including scrap metal and junk cars, and a containerized waste inventory.
In 1985, BIW capped the western portion of the site with an 18-inch layer of low permeable dredging spoils and native soils. The eastern portion of the site was capped as part of the final closure of the site in 1996. Twelve soil samples were collected as part of the Remedial Investigation in 1992. The samples were analyzed for VOCs, semi-volatile organic compounds (SVOCs), PCBs, and metals. VOCs, SVOCs, and metals were detected within two feet of the ground surface; however, this depth in soil is not considered to be the depth in soil that people would be exposed to. Detectable levels of PCBs were reported in one sample collected at a depth of four feet from the ground surface; and again, this depth does not represent a depth in soil that people would be exposed to. During the first and subsequent site inspections, there were strong odors of solvents in the area. However, during the 1987 site clean-up ambient air monitoring data showed negligible levels of volatile organic compounds.
BIW Corporation has been a responsible party in addressing the concerns to mitigate the threats posed by the Dauphin site. On December 14, 1989, BIW purchased approximately 54 acres, including the site, to assure control of any remedial measures taken at the site [6].
In 1990, the DEP submitted an Expanded Site Inspection report to the Environmental Protection Agency (EPA) for the site. In 1992, the Maine Department of Environmental Protection took surface water and sediment samples from outbreaks in the Tarbox Hill neighborhood. The samples were analyzed for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), metals, and PCBs. At that time, the sampling analysis identified elevated lead and polycyclic-aromatic hydrocarbons (PAHs) on the site. The State Toxicologist evaluated the concentrations detected and stated that the concentrations detected were not unusual for an average residential urban area, that they did not constitute a human health concern, and that the contaminants were probably not related to the Dauphin site [3]. In 1994, additional surface water and sediment samples were collected and no contaminants were detected at concentrations of public health concern.
In March 1994, the Agency for Toxic Substances and Disease Registry (ATSDR) received a petition request to prepare a public health assessment for the Dauphin Disposal site. ATSDR staff conducted a site visit, met with the community members and the facility employees. Based on the data collected during the site visit, ATSDR agreed to prepare a health consultation to address the community concerns related to the Dauphin site. In particular, ATSDR agreed to address possible public health threat posed by contaminants in groundwater, surface water, air, and soil and to review the available information regarding the possible relationship between the onset of nephrogenic diabetes insipidus in a child and exposure to lithium-containing materials that were possibly disposed of on the site.
In May 1995, ATSDR prepared a report/health consultation to address the petitioner's concerns about the possibility of lithium induced nephrogenic diabetes insipidus in the nine year old child [4]. ATSDR's research focused on the examination of the child's medical history, the history of the possible exposure, and the medical literature related to the subject. The report agreed with the medical diagnosis of nephrogenic diabetes insipidus; however, the document also stated that "there was not enough clear evidence of chronic lithium exposure to assign cause and effect" for the nephrogenic diabetes insipidus diagnosis [4].
On May 20, 1996, ATSDR finalized a Health Consultation to address the possible public health threat posed by contaminants in groundwater, surface water, air, and soil [5]. ATSDR reviewed and evaluated the data contained in the Phase I Remedial Investigation Report from September, 1994 and DEP's Expanded Site Inspection Report of March, 1990. In particular, ATSDR staff were tasked to determine if the data contained in these reports indicated that contaminants are at levels of health concern and if additional environmental sampling is needed to define the extent of contamination. The report concluded that more samples were need to better characterize groundwater and soil contamination and to make a better determination about contaminant migration off the site. ATSDR staff recommended that additional soil and groundwater samples be collected and analyzed and that access to the site be restricted. The document also recommended that access to the site be restricted. Currently, access to the site is restricted by a fence and a gate; the site is otherwise only accessible from the Dauphin residence via an unpaved road that extends west across the length of the site[1].
On July 11, 1996, the DEP requested that the EPA postpone federal activities to list the site on the National Priorities List (NPL). DEP stated that: no further federal involvement at the site would be necessary provided that BIW complete the work as scheduled; and, that the closure of the landfill effectively reduced surface water infiltration to the landfilled material, which reduced the concentration of contamination in groundwater (7). As part of this request, DEP explained that they initiated the 1992 Remedial Investigation (RI) to characterize the nature of the off-site and on-site contaminants and that investigation was followed by the phase II remedial investigation in 1995, and the community has been updated of all of the activities at the site since the initial inspection of the site and they supported the chosen remedial action for the site. In the request, DEP summarized the findings of the phase II remedial investigation as follows:
On November 4, 1996, the EPA Region I Superfund Program agreed with the Maine DEP that no further steps would be taken to list the site on the NPL [7]. On April 27, 1998, the DEP requested that the EPA remove the Dauphin Disposal Site from the active Comprehensive Environmental Response Compensation and Liability Information System (CERCLIS) list and place it on the archived CERCLIS list (8). This request summarized the activities at the site to date and stated that the 1996 Final Closure Plan for the landfill was approved and the work was completed in the fall of 1996. As part of this activity, an 18 inch compacted clay cap was constructed over the 7-acre eastern portion of the landfill. Also, in 1996, BIW completed the remedial investigation and feasibility study; these reports documented that groundwater concentrations do not exceed MCLs at the site perimeter monitoring wells, that surface water samples exceeded the state's water quality guidelines for iron and zinc (at levels that would not result in health effects), that sediments in the southwestern cattail wetland were impacted by the landfill leachate, and that low levels of VOCs and SVOCs were detected in the landfill soil and/or waste borings on the site. The focused feasibility study recommended a remediation plan for the wetlands at the southwest property boundary to improve the water quality exiting the southwest corner of the landfill where iron concentrations exceeded the state's water quality guidelines. In January 1997, DEP approved BIW's post closure/longterm monitoring plan to determine the effectiveness of the landfill and wetland remedial activities [8].
