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Water Health Assessment
(Dover Township) Toms River, New Jersey
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Non-target Organic Chemicals
Draft for Public Comment -- November 16, 1999
Non-target Organic Chemicals
Initial analyses by the NJDEP laboratory, using an analytic method designed for pesticides (USEPA Method 507), indicated the presence of a non-target compound that could not be tentatively identified, particularly in the April 4, 1996 sample from well 26 at the Parkway well field. Subsequent analyses by laboratories of the NJDEP, NJDHSS, USEPA (in Cincinnati, Athens, and Las Vegas)
and Union Carbide confirmed the presence of an unknown compound (Richardson et al., 1999). The USEPA Las Vegas laboratory determined the probable structure of the unknown substance, which was consistent with a chemical by-product known to be present in Union Carbide production wastes deposited at the Reich Farm Superfund site in 1971. This substance has been identified as a mixture
of isomers of 4-cyano-1,2,3,4-tetrahydro-a-methyl-naphthalene-acetonitrile (THNA) and 4-cyano-1,2,3,4-tetrahydro-1-naphthalene-propionitrile (THNP). Because these closely related compounds are formed as condensation by-products of the styrene-acrylonitrile co-polymerization process and are composed of one part styrene and two parts acrylonitrile, they are collectively referred to as styrene-acrylonitrile (SAN) trimer.
The concentration of SAN trimer in Parkway well 26 has ranged between approximately 3 and 5 µg/l, with concentrations tending slightly lower with time (Table 7c). Lesser amounts have been found in wells 28 (approximately 0. 1 µg/l) and, in the summer of 1998, in well 29 (Tables 7b and 7c). The level of trimer is estimated to have been approximately 6 µg/l in well 26 in April 1996,
although the analytical method was not designed to quantify the amount present. Diluted levels of trimer were present at the Parkway point of entry and in distribution system (school) sample points (at an estimated level of 1 µg/l or below) in the late March and early April 1996 samples. Based on a detailed review of chromatographs from Parkway well analyses conducted in 1990 by
Radian Laboratories for Union Carbide and USEPA, NJDEP staff concluded that SAN trimer was present in samples taken at that time.
Upon discovery of SAN trimer in November 1996, the Parkway well field was voluntarily closed by UWTR in response to requests from NJDEP and NJDHSS. A granular activated carbon (GAC) treatment system was designed and constructed for wells 26 and 28 by May 1997. Treated output from these wells is generally discharged to the ground, but may be directed into the distribution system during
periods of exceptionally high water demand. In May 1997, the remaining wells in the Parkway well field were restored to service, and the NJDEP and the NJDHSS instituted a program of frequent monitoring of the wells and point of entry. From early July to early September 1998, traces of SAN trimer were detected in well 29 (less than the method detection level of 0.1 µg/l), but not at the
Parkway point of entry. As described above for TCE, this contamination episode is thought to be related to over-pumping of well 29 relative to wells 26 and 28. SAN trimer may also have been present in a well 29 sample in February 1999. UWTR installed additional GAC treatment at the Parkway well field for wells 22 and 29, beginning in June 1999.
After the analytical method was modified to include SAN trimer as a target analyte, all wells in the UWTR system were sampled or re-sampled. No SAN trimer was detected in any wells other than 26, 28 and 29 at the Parkway well field.
At the time of its identification in the UWTR system, nothing was known of the toxicity of SAN trimer. Since that time, Union Carbide has sponsored genetic toxicology assays and short-term toxicity testing. This testing revealed that SAN trimer was mutagenic in two of five strains of Salmonella bacteria and that it induced chromosomal aberrations in Chinese hamster ovary cells, but there
was no evidence of mutagenicity in two other assays. The lethal single dose was estimated to be 440 and 590 mg/kg in male and female rats. A two-week repeat dosing study showed that daily doses of 300 mg/kg were lethal to rats, while doses of 150 mg/kg resulted in a variety of toxic effects including lethargy, tremors, anemia, and increased liver weight. There was no apparent short-term
toxicity at repeated doses of 75 mg/kg. Plans for further toxicological testing are being coordinated by the USEPA and a working group of scientists from the National Institute of Environmental Health Sciences, ATSDR, NJDEP and NJDHSS, with input from Union Carbide and a consultant to the Ocean County Health Department.
The NJDEP has formed a committee to evaluate the possible presence of other non- target chemicals, particularly in relation to the Reich Farm groundwater contamination plume. A preliminary evaluation indicates that the following chemicals may be present in the groundwater plume: tetrachlorophdialic anhydride; chlorendic anhydride; chlorostyrene; dichlorostyrene; bis(4-chlorophenyl) sulfone;
triallyl isocyanuratc; diphcnylhydrazine picratc or diphenyl amine; N-ethyl- and N-methyl-p-toluenesulfonamide: and SAN dimers. Other possible chemicals are being investigated. The NJDEP committee is expected to issue a report of their findings, separate from this Public Health Consultation. The NJDEP is also carrying out research projects to examine the application of expanded testing methods
in other drinking water supplies in the State.
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