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Water Health Assessment
(Dover Township) Toms River, New Jersey
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Target Organic Chemicals
Draft for Public Comment -- November 16, 1999
Target Organic Chemicals
Organic chemical testing results of UWTR samples are found in Tables 6a to 6d (volatile organic chemicals) and 7a to 7d (other organic chemicals).
Volatile Organic Chemicals (Method 524.2) Trichloroethylene (also called TCE) was detected in 11 of 21 distribution (school) drinking water samples from March 28, 1996 at concentrations up to 1.0 ug/l (Table 6a). TCE was found at 0.9 ug/l in one point of entry sample (Parkway)
on April 4, 1996, where it was also detected in three wells (26, 28 and 29) at levels of 5, 8 and 2 ug/l, respectively (Table 6b). The MCL for TCE is 1 ug/l. At the time of sampling, TCE was being removed from wells 26 and 28 through packed tower aeration treatment (also called an air stripper)
that was installed in 1988. Since no TCE was detected in the water exiting the air stripper, the TCE in the point of entry sample was most likely attributable to well 29. LTWTR temporarily directed well 29 water through the air stripper in April 1996.
As described below in the "Non-target Organic Chemicals" section, the Parkway well field was voluntarily taken off-line by UWTR in November 1996 and returned to service (with wells 26 and 28 being treated and pumped to waste) at the end of May 1997. TCE levels in both wells 26 and 28 have generally
ranged between 2 and 6 ug/l from mid-1997 to mid-1999, with levels in well 26 tending lower with time and levels in well 28 tending higher with time (Table 6c). In September and October 1997, traces of TCE (below the method detection limit) were found in well 29 but not at the point of entry.
TCE was measured at levels above the method detection limit in well 29 from July to early September 1998, (at less than I ug/1), but was not detectable at the Parkway point of entry in this period. This contamination episode is thought to be related to over-pumping of well 29 relative to wells 26 and 28.
The solvents tetrachloroethylene (also called PCE, or perchloroethylene), 1,1,1, trichloroethane (TCA), and 1,2-dichloroethane were also measured at levels up to 2 ggll in wells 26 and/or 28 in April 1996, but not in the distribution system (school) samples of March 1996. These chemicals were also
sporadically reported at lower levels in samples from other shallow Parkway wells. The MCLs for PCE, TCA and 1,2-dichloroethane are 1 ug/l, 30 ug/l and 2 ug/l.
TCE, PCE and TCA have been common groundwater contaminants in many areas of New Jersey and other parts of the United States. In the mid-1980s, when mandatory monitoring for volatile organics began in New Jersey, approximately 15 to 20% of community water systems contained these solvents at levels between I
and 100 ug/l (NJDEP, 19,97). Due to the imposition of State and federal standards by the late 1980s, the number of people served by community water systems with solvent contamination has decreased dramatically (Cohn et al., 1999).
TCE and PCE are classified by the International Agency for Research on Cancer (IARC) as probable human carcinogens, based on the weight of evidence from laboratory animal experiments and limited human epidemiologic studies (IARC, 1995). Following long-term, high level exposure, TCE has been shown to
produce liver cancer in mice and kidney and testicular tumors in rats (IARC, 1995; ATSDR, 1997a). Chronic, high level PCE exposure produces liver cancer in mice and kidney tumors and mononuclear cell leukemia in rats (IARC, 1995; ATSDR, 1996). Epidemiologic studies of occupationally-exposed workers
suggest an association between long-term inhalation exposure to high levels of TCE and increased risk of liver and biliary tract cancer and non-Hodgkin's lymphoma (IARC, 1995; ATSDR, 1997a). Increased risks of esophageal cancer, cervical cancer and non-Hodgkin's lymphoma have been observed in workers
exposed to high levels of PCE (IARC, 1995; ATSDR, 1996).
TCE and PCE exposure in drinking water has been linked to elevated incidence of cancers in human populations, including leukemia and/or lymphomas in children (MDPH, 1997; Cohn et al., 1994; Lagakos et al., 1984) and to increased risk of adverse developmental effects (Bove et al., 1995; ATSDR, 1997b).
Overall, the associations drawn from these limited epidemiologic studies suggest possible risk increases due to exposure to TCE and PCE in drinking water, but are inconclusive. Nonetheless, they do indicate the need for further epidemiologic study (Cantor, 1997). Participants in the ATSDR TCE Exposure Subregistry
(approximately 4,300 individuals with past exposure to TCE in drinking water at levels ranging from 2- to 19,000 jig/1) have not reported increased occurrence of cancer (ATSDR, 1993).
1,2-Dichloroethane is also classified as a probable human carcinogen (ATSDR, 1994), while there is no evidence to suggest that TCA is carcinogenic (ATSDR, 1995a).
Chloroform, bromodichloromethane, dibromochloromethane and bromoform are known collectively as trihalomethanes (THM). These compounds are formed as an unintentional result of chlorine disinfection of drinking water to destroy potential disease-causing (pathogenic) microorganisms. The low levels detected in the distribution
system (approximately I to 5 ug/l combined) are typical of groundwater disinfected with chlorine (Table 6a). In many parts of New Jersey where surface water is chlorinated for disinfection, THM levels are typically 25 to 75 ug/l.
Chloroform was also detected at low levels (generally less than I or 2 ug/1) with some consistency in some wells, prior to chlorination, indicating that this chemical is present in the aquifer. These wells are: wells 22 and 44 at Parkway, well 32 at South Toms River, well 31 at Route 70, and wells 33, 34 and 35 at Berkeley (Table 6b).
According to studies by NJDEP and the USGS, this chemical has previously been detected at low levels elsewhere in the shallow Cohansey aquifer. Although the source or sources are not known with certainty, chloroform in untreated well water may be present due to the common household use of bleach which is discharged to septic tanks and then into groundwater.
The MCL for the total concentration of the THMs is currently 100,ug/L. The safety of THMs and other chemical by-products of disinfection is currently under study. Some of the THMs and other disinfection by-products have been shown to be carcinogenic in laboratory animal studies (IARC, 1991; ATSDR, 1998a; ATSDR, 1991; ATSDR, 1989).
Epiderniologic studies of exposure to disinfection by-products indicate that long-term exposure to relatively high levels increases the risk of bladder cancer and possibly rectal cancer (Cantor, 1997; Morris et al., 1992). Recent studies suggest a possible increasein risk of spontaneous abortion or neural tube birth defects
from exposure to the relatively high disinfection by product concentrations found in chlorinated surface water supplies (Swan et al., 1998; Klotz et al., 1998). Federal regulations governing disinfection practices have recently changed to further limit by-product formation while ensuring effective destruction of pathogens.
Occasionally, other volatile organic chemicals have been detected within the UWTR system. Well 21 at the Holly well field had low levels of dichlorodifluoromethane (I to 2pgll) on two occasions in 1996 (Table 6b). Xylenes, toluene and/or ethylbenzene were measured (up to 12,ug/l combined) above the detection limits in six of 21 distribution
system (school) samples in March 1996, at many of the same sample points where TCE was detected (Table 6a). The MCLs for these compounds are 1,000, 1,000 and 700 pg/l, respectively. Ethylbenzene and toluene were measured at trace levels at the Parkway point of entry (but not in any of the component wells) in early April 1996. These compounds
are common solvents and are also components of fuel oil and gasoline. MTBE (methyl tertiary-butyl ether), another fuel component and frequent drinking water sample contaminant, has been sporadically detected at low levels (0.3 to 3.0 4g/L) in the Parkway and Route 70 wells and points of entry (Table 6b). MTBE was measured above the detection
limit in one school sample (Table -6a), but well below the New Jersey MCL for MTBE of 70 jig/I. Based on animal toxicology studies, MTBE is classified as a possible carcinogen by the USEPA (ATSDR, 1998b).
Naphthalene (also measured with one of the semi-volatile methods) was found on two occasions in Berkeley well 34 at a level up to 23 ug/l, and at a trace level in one sample from South Toms River well 38 (Tables 6a and 6b). A trace of naphthalene was also detected in one school (distribution system) sample (Table 6a) . The New Jersey MCL for
naphthalene in drinking water is 300 ug/I. The USEPA has determined that there is insufficient information to classify naphthalene as a carcinogen or non-carcinogen (ATSDR, 1995b)
Volatile organic chemicals were also found in comparison samples, including typically low levels of THMs (Table 6d). One community supply well also contained trace levels of 1,1,1-trichloroethane, 1,2-dichloroethane and MTBE, each below applicable MCLs.
Semivolatile Organic Chemicals (Methods 525.2 and 625) These methods revealed the presence of few originally targeted compounds, but the 525.2 method has now been modified by the NJDHSS Laboratory to measure previously unidentified chemicals (see Non-target Organic Chemicals section below). Of the original target compounds, phthalates and a related
substance (an adipate) were reported frequently, in both samples and in field, trip and laboratory reagent blanks, at levels generally less than 1 ug/l. The highest reported phthalate level was 2.3 ug/l (Table 7b). Phthalates and adipates are common components of plastic materials, and the low levels detected are likely to be a result of trace
contamination of the laboratory or sampling environment from ubiquitous plastics. For this reason, the NJDHSS Laboratory suggests that phthalates at levels below 2 or 3 ug/l probably reflect contamination during sampling, sample handling, and analysis. Even if present, the levels of phthalates are well below health-based guidance levels.
Reference guidance for di-n-butyl phthalate, butylbenzyl phthalate and diethyl phthalate in drinking water are 1000, 2000 and 5000 ug/L, respectively. MCLs for di(2-ethylhexyl) phthalate and di(2-ethylhexyl) adipate are 6 and 400gg/L, respectively.
Occasional trace levels of polycyclic aromatic hydrocarbons (PAHS) (for example, fluorene) were found in some well and distribution system (school) samples (Tables 7a and 7b). For the PAHs reported, health based guidance levels range from 300 to 3,000 ug/l.
In comparison samples, no phthalates (above 2 ug/l) or other semi-volatile target analytes were detected.
Pesticides and Related Compounds (Methods 504.2, 505, 507, 515.2, 53 1. 1) No target compounds were present above the method detection limit in any of UWTR distribution system, the point of entry or well water samples. One of the comparison community supply wells, however, contained a trace of the pesticide prometon at 0. 35 ug/l, far below the
USEPA Lifetime Health Advisory level of 100 ug/l (Table 7d).
Non-volatile Organics Polypropylene glycols (PPGS) were detected by the Rutgers CAFT laboratory in all three point of entry samples collected on April 4, 1996 and tested by HPLC-MS methods. None of the four comparison wells sampled in May 1996 contained PPOS. Between June and October 1996, all active wells were sampled for analysis by this method,
and none contained PPGS. No PPGs were detected in a sample of the lime used for corrosion control at the points of entry. Based on these data, it appears that the identification of PPGs in the original set of samples was a result of sample handling or laboratory contamination.
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 ug/l, with concentrations tending slightly lower with time (Table 7c). Lesser amounts have been found in wells 28 (approximately 0. 1 ug/1) and, in the summer of 1998, in well 29 (Tables 7b and 7c). The level of trimer is estimated to have been approximately
6 ug/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 ug/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 ug/1), 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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