The Tarbox Hill neighborhood consisted of eleven homes located near the site. BIW purchased the residences and the community relocated. BIW grouted all the residential wells when they purchased the properties and donated the residences to the Bath Housing Authority. Bath Housing Authority renovated and sold the homes. The homes are currently occupied and are supplied by municipal water(6).
This health consultation reviewed data available since the first inspection
of the site. There were a number of sampling rounds performed for the different
media as part of the investigative process of the activities at this site. The
particular information for each media is discussed further in the appropriate
subsections presented below:
GROUNDWATER
In 1986, DEP installed and sampled six monitoring wells on the site and collected samples from eleven private drinking water wells in the Tarbox Hill neighborhood. The samples detected volatile organic compounds (VOCs) and metals from on-site and off-site locations. At that time, DEP recommended that public water lines be connected to the residences near the site; the residences were serviced by municipal water lines beginning in the summer of 1987.
As part of the 1992 remedial investigation (RI), an additional 24 monitoring wells and one replacement well were installed on the site. VOCs were detected on-site samples; however, no contaminants were identified that exceeded the maximum contaminant levels (MCLs) detected on site perimeter monitoring wells. The remedial investigation also included a water supply and domestic well survey within 0.5- mile of the site, evaluation of historical analytical data, and an inventory of existing monitoring wells. The water supply and domestic well survey did not identify an apparent plume of contaminated groundwater that could be tracked back to the site [3]. Currently, there are 30 monitoring wells on-site that are monitored quarterly[3]. The residences located within a one mile radius of the site are serviced by municipal water.
SURFACE WATER AND SEDIMENT
In 1986, DEP collected surface water and sediment samples from four locations on the Dauphin site. The samples were analyzed for VOCs, semi-volatile organic compounds (SVOCs), and metals. VOCs were not detected in the samples; 1,4 dichlorobenzene was detected in all four locations and di-n-butyl phthalate was detected at two locations at very low concentrations. Lead was detected at 124 parts per billion (ppb) in one water sample collected from an on-site swamp area. While exposures from ingestion to this concentration of lead may result in adverse health effects, there is no indication that exposures occurred from someone drinking the water from the swamp area on site. In 1987, BIW submitted a surface clean-up plan for the site. The clean-up plan addressed the removal of surface wastes, including scrap metal and junk cars, and a containerized waste inventory. The removal activities were completed in September 1987 [3].
In May 1992, DEP collected surface water and sediment samples from the Tarbox Hill neighborhood from areas that the residents suggested and from areas where the surface water was discolored [3]. Sampling analysis indicated that manganese was present at concentrations that may pose health effects if the water was used for drinking; however, the water is not used for drinking. Six sampling locations were chosen as part of the remedial investigation in 1992. Each of the samples were analyzed for VOCs, SVOCs, metals and polychlorinated byphenyls (PCBs). Lead and polycyclic aromatic compounds (PAHs) were detected on the site; however, the concentrations detected were not above background concentrations and did not pose a risk to human health [3].
On December 28 1994, surface water and sediment samples were again collected and analyzed for VOCs, metals, and semi-volatile organic compounds [3]. VOCs and semi-volatile organic compounds were not detected above background concentrations, three metals (aluminum, chromium, and iron) were detected in a sediment sample above background concentrations but not at levels that pose a human health hazard.
SOIL
In 1985, BIW capped the western portion of the site. The eastern portion of the site was capped in 1996 as part of the final closure of the site [8]. There are no residences on the site and access to the site is restricted by a chain-link-fence and a locked gate. Twelve on-site soil samples were collected and analyzed as part of the RI. The samples detected VOCs, SVOCs, and metals within two feet of the ground surface and one sample showed elevated concentrations of PCBs at a depth of four feet; these depths in soil are not considered to represent depths at which people could be exposed to contaminants.
In 1992, DEP collected and analyzed soil samples from the Tarbox Hill neighborhood to determine whether site-related contaminants may have migrated into the residential area. The samples were collected from locations that the residents suggested. Sampling analysis identified lead and polyaromatic hydrocarbons at concentrations below background concentrations, that are not uncommon for an urban residential area [1].
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, people would unlikely be exposed. Detectable levels of PCBs were reported in one sample collected at a depth of four feet; and again, this depth does not represent a health hazard.
AIR
During the first and subsequent site inspections DEP staff noted strong odors of solvents on the site. However, during the site clean-up in 1987, ambient air monitoring showed negligible levels of VOCs that do not represent a risk to human health [3].
