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Dover Township Municipal Landfill & Silverton Private Well Contamination Investigation
Toms River, New Jersey
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Conclusions
Based on a weight-of-evidence analysis of the health and environmental information compiled, each Public Health Assessment assigns a hazard category (see Appendix) in response to the public health risk posed by the site being evaluated. Each category relates to a set of additional actions or
interventions that may be considered by the ATSDR, the NJDHSS or other public health agencies, as well as recommendations for further action to the USEPA, NJDEP or other environmental agencies.
Hazard Category for the Dover Township Municipal Landfill
Based upon the information reviewed, the Dover Township Municipal Landfill is considered by the ATSDR and the NJDHSS to have represented a public health hazard because of past exposures. This determination is based on the following considerations, taken together; 1) the presence of completed
exposure pathways in the past (through the use of private wells) to benzene, chlorinated benzenes, PCE, vinyl chloride and lead; and 2) toxicological evaluation of lead indicating a health hazard to the developing fetus and young children.
While a toxicological evaluation of the volatile organic contaminants in private wells, taken on an individual basis, would not indicate that an adverse carcinogenic or non-carcinogenic health effect is likely from past exposures, this evaluation is based on only one round of sampling and a limited
suite of analytical methods, and there remains uncertainty as to the duration and levels of exposure that residents may have experienced before their wells were tested. The exposure pathway through private wells adjacent to the landfill was interrupted through the provision of alternate water sources
and extension of the community water supply in 1991.
The DTML site is considered to represent no apparent public health hazard at present due to the absence of a current completed human exposure pathway. However, the nature and extent of the DTML groundwater contamination plume is currently under investigation, and the status of the DTML as a continuing
source of groundwater contamination has not been determined. The potential for a future exposure pathway associated with the use of private potable wells down gradient of the DTML site may be determined by the results of the on-going Remedial Investigation.
Hazard Category for the Silverton Private Well Contamination Investigation Area
The contamination of Silverton private wells is categorized as a public health hazard because of past exposures. This determination is based on the following considerations, taken together: 1) the presence of a completed exposure pathway in the past (through the use of private wells) to methylene chloride,
1,2-dichloroethane, chloroform, carbon tetrachloride, 1,2-dichloropropane, TCE, 1,1,2,2 tetrachloroethane, benzene and chlorobenzene; 2) toxicological evaluations indicating a public health hazard because of adverse non-carcinogenic effects of exposures to carbon tetrachloride and an estimated low
increased cancer risk from exposure to several VOCS; 3) epidemiologic studies in other populations suggesting that exposure to benzene and TCE may increase the risk of certain cancers; and 4) the presence of an excess of childhood cancers in the community. Because the exposure pathway has
been interrupted for the wells studied in this investigation, there is no public health hazard at present.
There was insufficient information available to the NJDHSS and the ATSDR to address the community's concern that groundwater contamination in the Silverton Private Well Contamination Investigation area was associated with the DTML.
The past completed human exposure pathway associated with the Silverton Private Well Contamination Investigation was of sufficient public health significance to warrant consideration of this pathway in the on-going epidemiological study
of childhood cancer incidence in Dover Township.
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