Reich Farm Health Assessment<BR>(Dover Township) Toms River, New Jersey

Reich Farm Health Assessment
(Dover Township) Toms River, New Jersey

Pathways Analysis

To determine whether residents of Dover Township were or are currently being exposed to contaminants migrating from the RF site, the NJDHSS and the ATSDR evaluate the environmental and human components that lead to exposure. An exposure pathway consists of five elements: (1) a source of contamination; (2) transport through an environmental medium-, (3) a point of human exposure; (4) a route of human exposure; and (5) a receptor population.

The ATSDR and the NJDHSS classify exposure pathways into three groups: (1) completed pathways, that is, those in which it is likely that some persons in the receptor population were exposed, are being exposed, or will be exposed; (2) potential pathways, that is, those in which exposure might have occurred, may be occurring, or may yet occur; and (3) eliminated pathways, that is, those which can be eliminated from consideration because one of the five elements is missing and will never be present, or in which no contaminants of concern can be identified. Completed or potential pathways may be interrupted by remedial actions.

Private Wells

The NJDHSS and the ATSDR have determined that a completed human exposure pathway to RF-related groundwater contaminants existed in the past through the domestic use of private wells. Exposure to some members of the population may have occurred through ingestion, inhalation or dermal contact, depending on water use patterns and volatility of contaminants.

The presence of contaminants is documented in private wells as early as 1974. Non-specific methods indicated the existence of contamination of unknown composition. However, the USEPA did find toluene (12 ppb), and styrene (30 ppb) in a well at one private residence in July 1974, using a method capable of detecting specific volatile organic compounds. These compounds were found in the material dumped at the RF site, and the private well is in an area now known to be in the path of the RF groundwater plume.

The specific locations affected, and the time of impact, is dependent upon the flow of groundwater, contaminant characteristics, and the location of wells relative to the path of the RF groundwater plume. Exposure through private wells is believed to have been interrupted in 1975 when wells were ordered sealed and community water supplies became available, although compliance with the directive met with some resistance (Ghassemi, 1976). There were an estimated 148 homes with private wells in the area designated as contaminated (Zone 1) by NJDEP. While the number of wells actually contaminated by RF is not known, the total number of persons potentially associated with this exposure pathway is estimated to be approximately 370 (148 residences times 2.5 persons per residence) (ATSDR, 1992).

Private wells continuing to exhibit contamination potentially related to the RF plume were reported after 1975, including nine wells with "phenols" in 1976 in the vicinity of Dugan Lane, south of the RF site. The duration of this exposure to phenolic compounds for persons using these wells is not known. The pathway was interrupted when the wells were ordered closed by the DTBH.

The specific chemical characteristics of the past private well exposure pathway cannot be determined from existing data. However, based on monitoring well data, the NJDHSS and the ATSDR have determined that a completed human exposure pathway to a variety of VOCs and SVOCs in groundwater existed in the past through domestic use of private well water in the vicinity of the RF site. The VOCs include TCE, PCE,1,1,1 -trichloroethane, toluene, styrene, benzene and others. The SVOCs include the SAN trimer, BEHP, and possibly others.

In general, the private well exposure pathway has been interrupted by the establishment of a well restriction zone and related well closure actions in the Pleasant Plains area. There is no indication that private wells are still in use in the area known to be above the RF groundwater contamination plume.

(It should be noted that an Ocean County ordinance passed in 1987 requires private potable wells to be tested for a variety of possible contaminants including volatile organic chemicals, when new and at the time of property transfer. This requirement provides an additional mechanism for the detection of local groundwater contamination problems and the interruption of exposure pathways.)

Public Wells (Parkway Well Field)

The NJDHSS and the ATSDR have determined that, for some members of the population, a completed human exposure pathway to RF-related groundwater contaminants existed in the past through the community water supply. Contaminants from the RF were discharged to groundwater and were later drawn into supply wells at the Parkway well field, and then pumped into the community water distribution system. The duration of this exposure pathway is unknown. The travel time of groundwater from below the RF site to the Parkway well field has not been established. Estimates by NJDEP and UCC (Malcolm Pirnie, 1992) have ranged between approximately five and 10 years, indicating that contaminants from the site may have reached the well field beginning some time in the period 1976 to 1981.

The chemical composition of past exposures cannot be determined, although since 1986 the following chemicals have been identified in the RF groundwater plume and in Parkway well field wells: TCE, PCE, 1,1,1-trichloroethane, benzene, toluene, 1,2-dichloroethane, chlorobenzene and the SAN trimer. Other chemicals may still be identified.

In 1986, there were not yet any federal or State MCLs established for TCE or other VOCS, although the NJDEP had established an interim guidance level of 2 ľg/l for TCE, above which remedial action was recommended. To achieve this level (and to reduce exposure through this pathway), water from contaminated Parkway wells was blended with water from other wells in the Parkway well field with the intention of introducing the water into the point of entry at no more than 2 ľg/l of TCE. However, according to newspaper reports at the time, samples at the Toms River Nursery School (located near the point of entry for the Parkway well field) taken subsequent to blending showed 3 ľg/l of TCE (OCO, 1987b). In addition, further sampling by the TRWC showed TCE levels above 2 ľg/l at Toms River High School North, and Intermediate West, with lower levels at North Dover and West Dover Elementary Schools (APP, 1987b). Subsequent to these tests, the TRWC closed the Parkway well field's Cohansey wells and began the planning and installation of a packed tower aeration system (air stripper) for wells # 26 and #28; the air stripper was installed and in operation by May 1988. This action served to interrupt the pathway for volatile organic chemicals.

However, this effort to interrupt the exposure pathway was not effective at reducing SVOCS, since semi-volatile chemicals are not removed by air stripping. In 1996, following the discovery of the SAN trimer, wells #26 and #28 were diverted from the water supply. An activated carbon treatment system has been installed for these wells; the treated effluent is primarily being pumped to waste. In June 1999, another activated carbon treatment system was installed to protect against sporadic RF-related contamination in well #29; treatment was also extended to the nearby well #22 as a precaution. Thus, the completed exposure pathway to VOCs and SVOCs from Parkway well field wells is now interrupted and should now be considered only a potential pathway. To ensure continued interruption of the exposure pathway, it is necessary to effectively manage the well field to contain the RF plume, and to properly operate and monitor the treatment systems now in place.

In 1986, well #23 had been found to contain 8 ppb of N-nitrosodiphenylamine. In the late 1980s and early 1990s, wells #23, # 25 and #27 at the Parkway well field were closed and sealed by TRWC. These actions would have served to eliminate exposure pathways associated with these wells.

The total number of persons associated with the completed exposure pathway through the Community water supply in the past is difficult to determine. Exposure potential is dependent upon the dynamics of the water system during the period in question, and the location of potentially affected residences relative to the point of entry within the water system. Because the Parkway well field is a major source of water for the community water system, the number of exposed persons was potentially large.

A summary of exposure pathways associated with private wells and community water supply wells at the Parkway well field is presented in the following table:

Complete Human Exposure Pathways Associated with Reich Farm

Path- way Name	Source	Enviro- nmental Media	Point of Expo- sure	Route of Expo- sure	Exposed Popul- ation	Contam- inants (Time Docu- mented)
Private Wells	Reich Farm Plume	Ground- water	Residences and other locations with private water supplies	Ingestion, dermal contact, inhalation	Residents (Estimated 370 persons at time of well closures in 1974 and 1975)	TOC (1974 to 1975 phenols (1976) VOCs/ SVOCs (1986)
Community Water Supply	Reich Farm Plume	Ground- water	Residences and other locations served by water from Parkway well field of the community water supply	Ingestion, dermal contact, inhalation	Residents receiving water from Parkway well field (Number unknown	VOCs/ SVOCs (1986 and 1987) VOCs/ SAN Trimer (1996)

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