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CIBA-GEIGY Corporetion

Ardsley. New York 10502-2699 Telepnone 914 478 3131

CIBA-GEIGY

November 5, 1986

Ms. Patricia Wells EPA Region II 26 Federal Plaza New York, New York 10278

Dear Ms. Wells:

The EPA Remedial Investigation Report for the Toms River CERCLA site, prepared by NUS Corp., has been reviewed by CIBA-GEIGY and its consul­tants arid specific comments on the Report are attached.

Submitted today also, as part of the CIBA-GEIGY comments, are the follow­ing documents:

"Hydrogeol,.,gic and Related Environmental Investigation" report prepared by AWARE Inc.,

"An Assessment of the Risks Associated with the Ground-Water Contamination at the Toms River Plant," prepared by ENVIRON Corp., and

"A Numerical Three-Dimensional Ground Water Flow Model of the Toms River Plant Area" prepared by ENVIRON Corp.

The contents of each of these documents relates to or supplements work performed by EPA and its contractors and, therefore, contains information which should be evaluated by EPA for inclusion in its future decision­making processes related to the Toms River CERCLA site.

Please feel free to call if you have questions related to these specific comments or to any of the documents submitted as comments •.

Sincerely,

Karline K. Tierney, Manager Environmental Protection

KT9:gg:31 Enc.

cc: Dr. John Trela New Jersey Department of Environmental Protection

234659

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CIBA-GEIGY CORPORATION

COMMENTS . ON

EPA REMEDIAL INVESTIGATION REPORT OF THE

TOMS RIVER PLANT SITE

NOVEMBER 5. 1986

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November 5, 1986

Introduction:

Comments on the EPA Remedial Investigation Report on the Toms

River Plant, N.J. CERCLA Site

Submitted by CIBA-GEIGY Corporation

At the beginning of the EPA Remedial Investigation of the Toms River Plant CERCLA Site, CIBA-GEIGY initiated hydrogeologic and risk assessment studies. The purpose of the studies was to supplement the information which EPA's RI would provide so that the maximum amount of useful scientific data would be available. It was the company's view that to design remedial measures effectively the best possible information and data base must b~ obtained. To perform the studies CIBA-GEIGY employed two firms of the highest calibre, AWARE, Inc. and ENVIRON Corp. AWARE has provided the "Hydrogeologic and Related Environmental Investigation" report, and ENVIRON has provided the reports entitled, "An Assessment of the Risks Associated with the Ground-Water Contamination at the Toms

·River Plant" as well as "A Numerical Three Dimensional Ground-Water Flow Model of the Toms River Plant Area."

To further assure the quality and thoroughness of this work, CIBA-GEIGY asked four eminent scientists in the fields of hydrogeology and modelling to act as an overview committee for the work of AWARE and E~~IRON:

- to assure scientific objectivity, and

- to bring professional expertise and judgement to bear in the design and implementation of the work performed.

The Committee consisted of: Dr. George Pinder, Consulting Hydrologist, Professor, Princeton

University, Committee Chair Dr. John Cherry, Consulting Hydrogeologist, Professor, University

of Waterloo, Ontario Dr. R. Allan Freeze, Consulting Engine~r, Groundwater Hydrology and

Geotechnics, Professor, University of British Columbia Dr. St-avros Papadopulos, President, Papadopulos & Associates

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Comments:

It was the overall view of CIBA-GEIGY and its consultant reviewers that the EPA Remedial Investigation Report is in general agreement with the major scope of the AWARE "Hydrogeologic and Related Environmental Investigation" report being submitted today as part of this comment package.

We would like to highlight the following areas in which the EPA report agrees with the AWARE document:

• the extent of the contaminant plume and its general configuration,

• the conclusion that the Toms River is a barrier to further eastward migration of the plume from the plant site,

the conclusion that an aquitard is continuous under the plant site and has prevented downward migration of the plume,

• the conclusi.o.n that the existing purge well system is performing its intenaed function of preventing further migration of the plume .under the Oak Ridge subdivision, and

. the elimination of the compactor and CaS04 disposal areas as potential contaminant sources.

We are concerned that the RI report indicates that EPA was hampered in its conclusions by the loss of considerable data which failed Quality Assurance/Quality Control requirements and also by its decision not to utilize information gathered by CIBA-GEIGY's consultants. We urge the Agency to make use of this additional information, collected by independent highly-respected consulting firms, in the development of the Agency's Feasibility Study.

The following is a discussion of certain issues we believe warrant further consideration by the Agency:

Public Health Issues, Section 8

The EPA Report, Section 8, Public Health Evaluation is, admittedly, qualitative. For a quantitative evaluation (using actual ambient data), please see the Environ Report "An Assessment of the Risks Associated with the Ground-Water Contamination at the Toms River Plant," submitted with this comment package.

The EPA RI Report states that "completed pathways" exist for exposure of the public utilizing ground water for domestic purposes southeast of the TRP site in the Cardinal Drive area. As described in the ENVIRON Report, there is no evidence from public surveys that any contaminated residential irrigation wells are currently, or will in the future, be used for drinking, cooking, or washing.

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CIBA-GEIGY implemented a purge well system on its property near the Cardinal Drive boundary in January 1985 that is arresting off-site migration of ground-water contaminants. Nevertheless, ground-water contamination already off-site will slowly migrate past the northern portion of the Oak Ridge subdivision towards the Toms River. For this reason, in May 1985, the Ocean County CIBA-GEIGY Advisory and Oversight Committee requested that all residents in the Oak Ridge Subdivision be advised not to use untested well water for drinking or other activities that could result in ingestion or extended contact. The Ocean County Health Department mailed a letter in May 1985 to all Oak Ridge residents that carried the recommendation of the Oversight Committee. Furthermore, CIBA-GEIGY independently has taken steps to insure the identification of all private wells that fall within the region of potential influence of the contaminant plume migrating from the TRP.

Comments Specific to Table 8.7 in the EPA RI Report

We note a number of discrepancies between the data presented in Table 8.7 entitled "Comparison of Chemical Contamination in Ground water vs Regulatory Standards and Criteria," Appendix 4.9 and data gathered from analyses of grour~-water and public surveys. Comments are as follows:

Well TW-1 -- This well is located at 126 Sun Valley Drive in the Oak · Ridge subdivision and has low level contamination as evidenced by both USEPA data and data collected by CIBA-GEIGY. However, 'this well is an irrigation well and discussions with the owner indicate that this well is operated by a timer mechanism between approximately 4:00 a.m. and 6:00 a.m. for lawn sprinkling. Since operation of the well is activated by a timer, the well is not available for use during other periods of the day.

Well TW-4 -- This well is located at 57 Cliffside Drive and is used as an irrigation well. Although USEPA indicates that this well was observed to contain 8 micrograms per liter (ug/1) of toluene, this does not exceed any standard or criteria of which we are aware. Furthermore, testing by CIBA-GEIGY does not indicate that this well is contaminated. From the plume maps contained in AWARE's report, this well is located a considerable distance south of the plume of contamination under the Oak Ridge subdivision.

Well GW-6 -- This well is located at 23 W. Ridge Road. We are puzzled as to why this particular well is included in Table 8.7 since the monitoring data presented in Appendix 4.9 does not indicate that this well is contaminated. For example, none of the priority pollutants monitored were above the detection limit, including barium, which apparently was the basis for including GW-6 on Table 8.7. Therefore, we do not believe that Well GW-6 should be included on Table 8.7. In addition, this well is due south of the plant adjacent to an area free of contaminants as evidenced by on-site monitoring well data •

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Well GW-11 This well is located at 1271 Coulter Street, a section of Toms River-which USEPA and CIBA-GEIGY studies indicate could not possibly be· contaminated from activities at the Toms River Plant. Coulter Street is located east of the Toms River where the ground-water flow direction is to the west, towards the Toms River Plant. Furthermore, monitoring data presented in Appendix 4.9 does not suggest that this well is contaminated with any priority pollutants, including nickel, which appears to be the basis for listing this well on Table 8.7.

Well GW-14 -- This well is located at 8 Hummingbird Lane and is acknowledged to have low level contamination. However, based on personal contact between CIBA-GEIGY and the owner of this well, this well has not been used for irrigation purposes for over a year. Furthermore, the owner is considering CIBA-GEIGY's offer to permanently close the well.

In conclusion, water quality data which we have evaluated based on samples collected by USEPA and consultants to CIBA-GEIGY do not indicate that any of the residential wells listed on Table 8.7 are cuttently being used in a manner which would result in significant. risk. Furthermore, only two of the five residential wells listed on Table 8.7 are located in the plume of contamination emanati~g from the Toms River Plant. In addition, only one of these wells is currently in operation; it is only being used between 4:00 a.m. and 6:00 a.m. for lawn watering and, according to the owner, for no other purposes. Thus, we see no basis for concluding that human exposure exists.

The format for Table 8.7 is also misleading. The discussion in the text only refers the reader to the findings for the residential wells and monitoring wells 4-D and 1-XD. No discussion is included that addresses the significance of the maximum values reported for the Rl monitoring wells, or the locations of the RI wells with respect to the residential wells. Without such a discussion, the Rl well data could be misinterpreted as representing actual levels of human exposure. Either these values should be dropped from Table 8.7 or properly discussed.

In addition, Table 8.7 compares residential well contaminant levels with drinking water MCL and RMCL levels and suggests a health concern for residents using such well water. This approach to risk assessment ignores the RI report's conclusion that:

"There is no evidence that private drinking water of the area residents have any chemical contamination" (P. 8-13)

"There is no evidence that residents private drinking wells are contaminated" (P. 8-33)

" ••• no evidence exists that contaminated groundwater is ingested routinely or even used except for agricultural purposes" (P. 8-33)

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Since the RI concludes that there is no drinking of contaminated well water, use of MCL and RMCL levels for comparison purposes is completely misleading and inaccurate. The reason for this is the fact that MCL and RMCL levels are calculated assuming a person ingests two (2) liters of water per day for an entire lifetime. This kind of exposure is clearly not occurring and therefore unduly exaggerates the true risk of any potential exposure for residents in the Cardinal Drive area. Instead, the more usual EPA approach to risk assessment would estimate exposure levels based on current residential well use and then compare these values to the acceptable daily intake (ADI) or unit cancer risks (UCR) for each contaminant.

Comments on Potential Toms River and Marshlands Exposure

The RI also suggests that the potential human exposure to contaminants released to the Toms River and the marshlands along the shoreline of the river is "of concern." Review of these potential exposure pathways by ENVIRON Corporation (1986) indicates that there is no evidence of a significant risk to public health or the aquatic environment from foreseeable exposure to such contaminants. Their assessment quantitatively e·. aluated the risk from potential exposure to all volatile organics, acid extractable, and base/neutral extractable compounds identified and quantified in ground-water, surface water, or sediment samples from the Toms River site. Specific scenarios evaluated included: 1) a marshland area of the Winding River Park in which children play and therefore might be exposed through inhalation of contaminated air, contact with, and ingestion of contaminated soil and surface water; (2) recreational uses of Toms River which could lead to river soil exposure due to unintentional soil ingestion and dermal absorption, river water exposure from unintentional water ingestion and dermal absorption, and inhalation of volatile organics; 3) ingestion of fish that are contaminated from the Toms River. The mass loading of contaminants to the Toms River were calculated based on maximum contaminant concentrations fround in ground-water samples taken from wells adjacent the river. Dilution calculations were then performed on the mass loadings entering the river to estimate river concentrations of each contaminant.

All exposure scenarios examined by ENVIRON predicted worst case ca~5er risks, using extremely conservative_f~sumptions in the range of 10 (one case per ten million exposed) to 10 (one in one trillion). Furthermore, noncancer risks are not expected to occur because all predicted average daily intakes of contaminants were found to be less than the acceptable daily intake for all exposure scenarios. Lastly, ENVIRON's review of potential aquatic effects on the Toms River indicate contaminants discharging into the river are likely to have no impact on aquatic organisms.

Comments on Section 8.4

Some toxicity profiles included in Section 8.4 of the RI are neither accurate nor complete. The profiles for the carcinogens do not reflect the most current USEPA Carcinogen Assessment Groups (CAGs) determinations of unit cancer 1isks (UCRs). The inconsistencies are reflected in Table 1.

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The toxicity profiles also lack certain information that is important for safety assessment. For example. the profile for 1.2.4-trichlorobenzene states "no relevant information was found .•• " yet EPA published an acceptable daily intake (AD!) in January 1986. In addition. no AD!s have been included for the chemicals. These are needed to complete a quantitative risk assessment of noncarcinogenic effects. Such ADis have been published by the EPA and should_be included.

Table 1

UCR listed in EPA CAG UCR*

Chemical RI (mg/kg/day) -1 mg/kg/day -1

Benzene 2.59 x 10-2 2.9 X 10 -2

4.45 X 10-2

Chloroform 7.0 X 10 -2 8.1 X 102

Tetrachlorobenzene 3.98 X 10 2 5.1 X 10-2

Trichloroethene 1. 9 X 10 -2 1.1 X 10-2

*USEPA. September 1985. Health Assessment Document for Chloroform

Office of Health and Environmental Assessment. EPA/600/8-84/004F •

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Hydrogeologic Issues

While terrain conductivity data can be a helpful investigative tool in certain problem areas. it does not replace direct measurements. Perhaps EPA has relied too heavily on this relatively recent geophysical tool in drawing their conclusions. In several instances, for example, the EPA report suggests that the axis of the Cardinal Drive plume originates a considerable distance south of the Former Landfill. Isoconcentration maps prepared by AWARE for a variety of compounds do not support this contention. EPA also suggests that contamination from the Former Landfill has migrated to the vicinity of the Emergency Storage Reservoir. Again, this contention is not supported by the water quality data, nor is it supported by the water level data. By electing to exclude data from on-site CIBA-GEIGY monitoring wells, EPA has been forced to rely too heavily upon an indirect technique (terrain conductivity). Instead of qualifying interpretations to reflect the uncertainty inherent in assessing such indirect data, however, EPA has elected to assign them the status of established fact. This is not justified, particularly given the substantial database available for review.

Ground penetrati:.g 'radar can be a helpful investigation tool. It is, however, difficult to interpret and the conclusions regarding drums in the Former River Lagoon and Sludge Disposal areas seem to lack documentation. The supporting data package from Weston Geophy.s~cal includes only descriptive references to potential "point targets" with no

·documentation for the conclusion that they represent drum5. In all other areas, the data are available for independent review; what is lacking are the actual radar records. Without the radar records the interpretations advanced by the EPA Report cannot be independently confirmed or verified.

Perhaps it would be prudent to point out the enormous uncertainty associated with estimating the volume of sludge in the River Lagoon area based upon one boring per lagoon/sludge drying pit. NUS presents (in Table 3.2) estimates of the volume of sludge contained within each lagoon or sludge drying pit. These estimates are obviously based upon the premise that the conditions observed in the single boring within each lagoon/sludge drying pit can be extrapolated to conditions within the entire lagoon. We submit that this is a misleading assumption. There is little reason to suggest that of the sludge observed within the borings exists in laterally extensive laminae or beds. In fact, given that efforts were made to excavate the sludge during closure of the lagoons, the likelihood is that a uniform "stratigraphic section" of native soil and sludge does not exist. More likely, soil and residual sludge exist in a rather complex three-dimensional matrix that it cannot be adequately represented by a single boring in each lagoon.

The danger in these extrapolations of the data is that it places undue credence on the estimates of sludge volumes. Moreover, it tends to give the false impression that there is an adequate understanding of the spatial distribution of contaminants within the river lagoon area - which is not the case.

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Sufficient data must exist at the feasibility study stage to ensure, with a reasonable degree of certainty, that the correct remedial program is chosen. A single boring within a closed lagoon, particularly one with a complex internal structure, does not provide the informational frame work from which to select an appropriate remedial action.

In addition, the critical issue of the hydraulic conductivity of the various aquifers and aquitards is barely addressed. Where this issue is addressed (Table 4-1), no distinction is made between vertical vs. lateral hydraulic conductivity. There appears to be, as well, an inconsistency in the permeability and transmissivity ranges presented for the Kirkwood formation. There apparently is a typographical or other error in this table. Since transmissivity is defined as permeability times thickness, the Kirkwood formation would be unreasonably thick using the permeabilities and transmissivities in Table 4-1. Moreover, there is no presentation of typical groundwater flow rates or velocities, nor is there discussion of contaminant migration rates or velocities. The report is strikingly qualitative in this regard. Together with the data provided in the AWARE Report, however, there should be sufficient information available to perform a technically justifiable assessment of groundwater-based' ~emedial alternatives;

Throughout the report, the waste water treatment plant is referred to as a contaminant source. We believe that the former waste water treatment area underlying the current waste treatment plant is the real source of contamination being described. This is probably more a matter of terminology than of misunderstanding but the matter should be clarified. Any possible contribution to the plume from the Equalization Basins currently in use will end when these basins are closed and replaced with above ground tanks (scheduled for 1987).

The Report's conclusion that the "waste water treatment plant" is the source of contamination at the RI #9 area is not in agreement with the conclusions of the AWARE Report nor in agreement with the information generated by the ground-water model prepared by ENVIRON. Detailed discussion of this issue is included in the AWARE report submitted as part of this comment package.

According to the EPA RI Report, the currently active secure landfill is eliminated because it is permitted by another authority. It should be noted that existing data shows that the landfill is not leaking.

On pg. 3-29 of the RI Report, it is stated that "the high closure centered on well 0161, in fact, suggests that perched ground water is being drawn through or around the edge of the shallow clay by wells 746 and 747." Unfortunately, due to an error in measuring well elevations, this conclusion is no longer operable. New data provided today will be helpful in this regard.

The above summarizes our major comments concerning the EPA's Remedial Investigation report. These comments are based on the extensive hydrogeologic investigation conducted by AWARE, Inc. and the risk assessment and three dimentional model of the gr~undwater prepared by ENVIRON Corporation.

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AN ASSESSMENT OF . THE RISKS ASSOCIATED WITH

THE GROUND-WATER CONTAMINATION AT THE TOMS RIVER PLANT

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AN ASSESSMENT OF THE RISKS ASSOCIATED WITH

THE GROUND-WATER CONTAMINATION AT THE TOMS RIVER PLANT

Prepared for:

CIBA-GEIGY Corporation Ardsley, New York

Prepared by:

ENVIRON Corporation Washington, D.C. Princeton, N.J.

November 5, 1986

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CONTENTS

·EXECUTIVE SUMMARY .. i

I. INTRODUCTION . I I I I I I I I I I I I I 1

II.

II I.

IV.

v.

VI.

VII.

DESCRIPTION OF THE SITE.

HYDROGEOLOGY OF THE SITE .

METHODOLOGY FOR ASSESSING PUBLIC HEALTH RISKS ASSOCIATED WITH THE GROUND-WATER CONTAMINATION

POPULATIONS POTENTIALLY SUBJECT TO EXPOSURE.

IDENTIFICATION OF CHEMICALS OF CONCERN

RISK CHARACTERIZATION .....

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VIII. UNCERTAINTIES AND LIMITATIONS IN THE RISK ASSESSMENT 60

IX. SUMMARY AND CONCLUSIONS. 66

REFERENCES .

APPENDIX A:

APPENDIX B:

APPENDIX C:

APPENDIX D:

APPENDIX E:

APPENDIX F:

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Analytical Data

Status of Irrigation Wells In Oak Ridge Subdivision

Detailed Description Of Steps 3,4,5, and 6 Of Public Health Risk Assessment Methodology

Toxicity Profiles

Exposure Scenarios For Modeling Public Health Risks

Tables Presenting Exposure Scenarios And Assumptions, Contaminant Concentrations, and Risks For Potentially Exposed Human Populations

APPENDIX G: Inhalation Exposure - Model Validation

APPENDIX H: Air Monitoring Results

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TABLE 1:

TABLE 2:

TABLE 3:

TABLE 4:

TABLE 5:

LIST OF TABLES

Page

Potential Contaminant Source Areas 4

Ground-Water Wells Used to Estimate Containment Loading to the Toms River 31

Input Values and Calculated Mass Loadings 33 to the Toms River

Estimated Maximum Contaminant Concentrations 41 in the Toms River

_Aquatic Toxicity Data for Chemicals Evaluated 58 for the Toms River

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FIGURE 1:

FIGURE 2:

FIGURE 3:

FIGURE 4 :

FIGURE 5:

FIGURE 6:

LIST OF FIGURES

Site Map of TRP

Generalized Hydrogeologic Cross-Section 8

Generalized Isoconcentration Map in the 10 Lower Cohansey

Generalized Isoconcentration Map in the 11 Primary Cohansey

March, 1986, Sampling Locations 13

Steps in Hazardous Waste Site Public 18 Health Risk Assessment Methodology

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EXECUTIVE SUMMARY

ENVIRON Corporation has assessed the potential risks to public health and the environment which may result from the discharge of contaminated ground water from the Toms River Plant of CIBA-GEIGY Corporation. The Toms River Plant, which is located in Dover Township, Ocean County, New Jersey, manufactures dyes, epoxy resins, and various specialty chemicals. This risk assessment is based upon a comprehensive investigation conducted by AWARE, Inc. to characterize the hydrogeologic conditions of the site and to determine the nature and ·extent of soil and ground-water contamination. The methodology used by ENVIRON for this risk assessment is consistent with methods developed by the National Academy of Sciences (NRC 1983) and by USEPA in their Superfund Public Health Evaluation Manual (USEPA 1985b).

ENVIRON concludes that there is no evidence of a significant risk to public health from foreseeable exposure to contaminants migrating inground water from the Toms River Plant even if no remedial measures were to be instituted. The quantitative risk estimates derived by ENVIRON for human pealth effects are based on assumptions which tend to overestimate the exposures to contaminants discharged from the Toms River site. ENVIRON's risk assessment provides an estimate of the upper bound potential risks. Even so, the risk estimates obtained for carcinogenic effects are in the range of 10-7 (one case in ten million exposed) to l0-12 (one case in one trillion exposed) for the exposure scenarios examined. These risk levels are well below the risk levels generally found to be significant by public health regulatory agencies. Noncarcino­genic health effects are not expected to occur under any of the assumed conditions of exposure since the predicted average

J daily dose for the contaminants identified was found to be less than the acceptable daily intake for all exposure scenarios

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This risk assessment is based on the volatile organics, base/neutral, and acid extractable organic compounds that have been identified and quantified in ground-water, surface water, or sediment samples. In addition, an air monitoring program designed to measure volatile organics was conducted in a marshland area of the Toms River located within Winding River Park. This risk assessment will be revised as appropriate in light of any additional analytical data or hydrogeological findings that have a material bearing on the potential risk.

AWARE's hydrogeological investigation determined that ground-water contamination is confined to the Cohansey Sand aquifer and.that the Toms River and its associated flood plain serve as a hydrogeological boundary for ground-water flow within the Cohansey Sand aquifer. Moreover, public and private well systems on adjacent properties appear to be unaffected by the discharge from the Toms River site except for private wells in the path of the plume moving eastward to the Toms River through the northern portion of the Oak Ridge Subdivision. The Toms River Water Company currently supplies water to all homes in ~he Oak Ridge Subdivision; however, it is known that some private domestic and irrigation wells are still in use in this area. In August of 1986, CIBA-GEIGY conducted a door-to-door survey in an area which included the area of known ground-water contamination plus a four block buffer zone to the south. Fourteen irrigation wells were located in this area; no domestic wells were found. Samples were taken from 11 wells for analysis. Three wells were not sampled by CIBA-GEIGY, however, as two wells were not operational and one homeowner located in the southern most portion of the buffer zone refused to have his well sampled. CIBA-GEIGY offered to seal the wells or to periodically test those wells which suggested evidence of contamination.

Of the irrigation wells sampled by CIBA-GEIGY, only three wells exceeded standards or proposed standards established by

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the USEPA under the Safe Drinking Water Act. Since that time one homeowner accepted CIBA-GEIGY's offer and his irrigation well was sealed. Although arrangements have not yet been made for closure of the other two irrigation wells, one well has reportedly not been used since 19B5 and the other home uses its irrigation well only for lawn watering via an in-ground sprinkler system.

Therefore, since no sampled irrigation wells which exceed USEPA existing or proposed drinking water standards for organic . chemicals are being used for body-contact domestic purposes (drinking, cooking, bathing, swimming pools, etc.), ENVIRON did not conduct· a risk assessment associated with the use of irrigation wells. Moreover, CIBA-GEIGY has informed ENVIRON of the actions taken and planned to identify and seek closure of potentially affected wells in the Oak Ridge Subdivisio~. ENVIRON believes these actions will effectively preclude exposure to potentially contaminated ground water from this source.

As part of the risk assessment process, ENVIRON developed hypothetical exposure scenarios to define the upper bounds of reasonably foreseeable exposures to contaminants in soil and ~n ground-water migrating from the site. ENVIRON identified two potential areas of exposure to contaminants discharged from the

site:

• Ground-water seeps which discharge to the surface in the marshland or flood plain areas of the Toms River in the Winding River Park; and

• Ground-water discharging to the Toms River in areas used by the public for recreational activities.

Specifically, ENVIRON focused its attention on the discharge of contaminants (1) in ground-water seeps in the marshland area located on the western bank of the river, adjacent to the northern section of the Oak Ridge Subdivision; and (2) to the Toms River from the area that stretches as far

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north as the plume has been delineated (i.e., at the ox-bow area where contaminants discharge to the river's flood plain on its eastern bank) to the southern perimeter of the contaminant plume.

The marshland area is close to and easily accessible from the Oak Ridge Subdivision and is adjacent to a recreational area of Winding River Park. Consequently, possible public contact with the area of ground-water discharge in the marshland area may occur. The marshland area was sampled between the contour lines of highest total volatile priority pollutants (as prepared by AWARE). Six sediment samples and three water· samples revealed the presence of volatile organic contaminants and provided the basis for the health risk assessment associated with potential exposures in the marshland area. ENVIRON also used the concentrations of contaminants detected in marshland surface waters to estimate air concentrations of volatile organic pollutants. To validate these estimates, air concentrations were measured by Radian Corporation during a September, 1986 field sampling event .

A number of exposure pathways were evaluated by ENVIRON to assess potential risks associated with exposures in the marshland area of Winding River Park. These are:

• ingestion of and skin contact with contaminated soil;

• ingestion and skin contact with contaminated surface water; and

• inhalation of volatile organic chemicals.

For carcinogenic effects, the estimated upper bound lifetime cancer risks ranged from 10-7 (one case in ten million exposed) to 10-8 (one case in one hundred million

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exposed). Noncarcinogenic effects are not expected to occur since the predicted average daily dose for the contaminants identified was found to be less than the acceptable daily intake .

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Extensive hydrogeological investigations have identified a plume of contaminated ground~water which discharges to the Toms River. ENVIRON evaluated whether there are potential health risks associated with recreational use of the Toms River. Contaminant concentrations in ground-water wells nearest to the Toms River were used to estimate the maximum concentration of these chemicals that would be expected in the river. ENVIRON estimated the concentration of thirty chemicals in ground water discharging to the portion of the river along which the plume of contamination has been identified; however, actual sampling of river water, in March, 1986 did not reveal the presence of any priority pollutants at concentrations above the method of detection. River sediment samples were also collected in March, 1986. A number of volatile organic compounds were found in these samples, and the results obtained were used by ENVIRON to assess potential public health risks from exposure to river sediments.·

ENVIRON considered several exposure pathways associated with recreational use of the Toms River:

• ingestion of and skin contact with contaminated sediment;

• ingestion of and skin contact with contaminated water; and

• ingestion of fish.

For carcinogenic effects, the estimated lifetime upper bound risks ranged from 10-7 (one case in ten million exposed) to 10-12 (one case in one trillion exposed) for all

carcinogens. Noncarcinogenic effects are not expected to occur because the predicted average daily dose was found to be less than the acceptable daily intake for· all of the identified

contaminants.

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A preliminary evaluation of potential effects on the aquatic environment of the Toms River was performed. ENVIRON compared predicted river concentrations of contaminants w~th the lowest concentrations at which adverse effects on aquatic

. organisms have been reported. For each compound, the predicted river concentrations are at least several orders of magnitude lower than the lowest concentrations at which toxic effects have been reported in aquatic organisms. As stated above, analysis of river water samples did not reveal any priority pollutant at concentrations above the method.detection limit. In addition, analyses of river sediments indicate contaminant levels are far below toxic levels identified for various aquatic species. Based on the data available, ENVIRON concludes that contaminants discharging to the Toms River are likely to have no adverse impact on aquatic organisms .

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I. INTRODUCTION

The CIBA-GEIGY Corporation owns and operates an organic chemical and dye manufacturing plant on approximately a 1,255 acre site in Dover Township, Ocean County, New Jersey. The Toms River Plant ("TRP") has been in operation since 1952, initially producing organic dyes and intermediates. From 1959, epoxy resins and specialty chemicals were also produced at the site. Approximately 320 acres of the site are developed, including 7 production buildings, administration and laboratory facilities, an on-site wastewater treatment plant and land disposal operations. The site is bounded by the Toms River to the east and northeast and by residential and commercial development to the south and west. Because of ground-water contamination, the entire TRP site has been designated as a Superfund site by USEPA and NJDEP.

Hydrogeologic studies performed by AWARE, Incorporated (AWARE, 19.86) have defined the southern portion of the contaminated ground-water plume to be migrating from the site beyond the property boundaries in the Cardinal Drive area of the Oak Ridge Subdivision. The northern portion of the plume, comprised largely of volatile organic contaminants, is migrating towards the Toms River. This plume passes beneath the active channel of the Toms River and discharges to the flood plain on the east bank of the river (AWARE, 1986).

ENVIRON Corporation has been retained by CIBA-GEIGY to perform an assessment of potential public health risks posed by the migration of ground-water contaminants beyond the plant boundaries. The purpose of this risk assessment is (1) to identify the significant pathways of human and environmental exposure to ground-water contaminants migrating beyond the TRP property boundaries; (2) to identify potential receptors; and (3) to define the current level of risk to public health represented by migration of contamination from the site.

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ENVIRON has identified two locations of potential human exposure at which to evaluate risks to public health posed by contaminants migrating from the TRP: (1) the marshland area of Winding River Park where the southern portion of the plume discharges to the Toms River and to adjacent w~tlands on the west side of the river; and (2) the portion of the Toms River that borders the plant site.

The basic methodology and assumptions used to develop the exposure scenarios have been applied in previous risk assessments performed by ENVIRON Corporation. Exposure scenarios for the TRP were developed based on the conservative assumption -that current exposures would continue indefinitely. Current on-site risks and potential future risks such as those that might be associated with remedial action at the site were not assessed as part of this study.

ENVIRON's analysis is based on hydrogeological data specific to the TRP presented in a comprehensive hydrogeological report prepared by AWARE, Incorporated on behalf of· CIBA-GEIGY (AWARE, 1986). In addition, ENVIRON requested that JTC Environmental Consultants and Radian Corporation collect supplemental ground water, sediment, surface water, and air sampling data for use in this risk assessment.

The next two sections of this report review the background of the TRP site, the hydrogeology of the site, and the extent of contamination. In Section IV, the risk assessment methodology used in developing this analysis is presented. The populations at risk of potential exposure to contaminants are described in Section v. Section VI reviews the available chemical databases, and Section VII presents the results of the risk calculations for the different scenarios. A discussion of the limitations inherent in this risk assessment is presented in Section VIII. Finally, Section IX contains our conclusions based upon the findings of this risk assessment.

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II. DESCRIPTION OF THE SITE

A. Manufacturing Processes TRP manufacturers several hundred .different products

including dyes and intermediates, epoxy resins and various specialty chemicals for the textile, paper, automotive and plastics industries. Chemicals are produced at TRP by batch reactions using over 60 generic processes, whereby approximately 100 different products are being made at any one time. Since the inception of the site in the early 1950's, wastes generated at the facility have typically been managed on-site in -several distinct waste management areas.

B. On-site Treatment and Disposal of Waste As noted by AWARE (1986) in its hydrogeological report,

potential contaminant source areas include the former sludge disposal area, the former unlined landfill, the former lime waste area, the former river lagoon area, the former oxidation and settling basins where the new wastewater treatment plant presently is located, the compactor area which was also the site of a former rubble landfill, the former calcium sulfate disposal ·area, the former fire prevention training area, the current equalization basins which are located in the same area as former equalization basins installed in 1952, and the process areas of the plant. A description of these potential contaminant source areas is presented in Table 1. Figure 1 is a site map of the TRP, showing the locations of these areas.

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TABLE 1

POTENTIAL CONTAMINANT SOURCE AREAS

Potential Contaminant Source Area

Former Sludge Disposal Area

Former Unlined Landfill

Former Lime Waste Area

Former River Lagoon Area

Treatment Plant Area

Compactor Area

Status of Background Information

Inactive; contains treatment plant sludge excavated from sludge drying beds and from lagoons formerly located at the site of the present wastewater treatment plant; sludge was generated between 1952 and 1976; covered with soil and vegetated.

Inactive; contains wide variety of industrial wastes in bulk and in drums; capped with 30 mil PVC liner, and two feet of vegetated soil.

Inactive; contains lime with calcium arsenite; capped with 30 mil PVC and vegetated .

Inactive; site of three wastewater lagoons and two sludge drying beds; much of sludge from the three lagoons was hydraulically removed, filtered, and placed in the double-lined landfill in 1978; residual sludge remains in the two sludge drying beds which were covered with clean soil.

Site of former treatment plant; current treatment plant consists of concrete tanks; evidence of soil contamination from former unlined lagoons exists in the area.

Inactive; contains predominately construction debris although the presence of industrial wastes is also possible.

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TABLE 1 (cont'd)

POTENTIAL CONTAMINANT SOURCE AREAS

Potential Contaminant Source Area

Former Calcium Sulfate Disposal Area

Former Fire Prevention Training ~rea

Equalization Basins

Process Area

Status of Background Information

Inactive; contains calcium sulfate sludge; covered with soil.

Inactive; oils and solvents were burned in kettles in this area.

Active; receives process wastewater and stormwater runoff prior to treatment.

Active; potential specific source areas include sewers, underground storage tanks, and waste storage areas .

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trichloroethylene has been found at concentrations as high as 25,000 ppb. The ground-water data used in this analysis are presented in Appendix A .

Surface water and stream sediment sampling has been performed by NUS Corporation (April, 1985), USEPA's contractor for the Superfund Remedial Investigation. The sampling program included collection of surface water samples from nine locations in the Toms River and collection of stream-bottom sediment samples from the locations within the river channel.

In addition, JTC Environmental Consultants, under the direction of ENVIRON, collected stream samples at four locations and river sediment samples at two locations in March, 1986. JTC collected surface water samples above RI-9; at the RI-9 ox-bow; at RI-8 and in the river below the marshlands (i.e., below the Cardinal Drive plume discharge). These locations are indicated on Figure 5. No priority pollutants were found·above the published detection 11mit for the EPA designated method of analysis.

Sampling of the marshland area was conducted by JTC on March 4, 1986. The six sediment and three surface water sampling locations are shown in Figure 5. Additional surface water samples were taken by Radian Corporation on September 11, 1986 during the conduct of an air monitoring program in the marshland areas.

The results of the NUS and JTC analyses are presented in Appendix A. Results of the Radian field sampling effort are presented in Appendix H.

C. Cardinal Drive Purge Wells In January 1985, CIBA-GEIGY activated a purge well system

perpendicular to the axis of the southern portion of the contaminated ground-water plume migrating from the site beyond the property boundaries in the Cardinal Drive area of the Oak Ridge Subdivision. This purge well system has effectively captured contaminants migrating from the area of the landfill.

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water supply. Based on AWARE's hydrogeological investigation, this area is upgradient of the ground-water movement at the site and is therefore unaffected by the existing contamination. Three smaller residential areas east (across the Toms River from TRP), south and southwest of TRP also use private wells. These areas have also been found to be unaffected by the ground water discharged from the TRP site (see Appendix B).

Residents in the Oak Ridge Subdivision southeast of the plant receive water from the Toms River Water Company. The Water Company has determined that all residences in the Oak Ridge Subdivision are their customers. However, according to Ocean County Health Department records, nine domestic wells and at least 15 irrigation wells are known to exist in this neighborhood.

As described above, CIBA-GEIGY activated a purge well system in the Cardinal Drive area in 1985 to arrest the off-site migration of ground-water contaminants. The tail of the southern portion of the plume of contamination, however, continues to migrate beneath the Oak Ridge Subdivision towards the Toms River. In May, 1985, the Ocean County CIBA-GEIGY Advisory and oversight Committee requested that the Ocean County Health Department notify all residents in the Oak Ridge Subdivision vicinity of the potential contamination of their wells. Residents were advised not to use untested well water for drinking water purposes or for activities that could result in ingestion or extended contact. The letter asked all residents to contact the Board of Health.

CIBA-GEIGY has independently taken steps to insure the identification of all private wells that fall within ~he region of potential influence of the contaminant plume migrating from the TRP. In June of 1986, CIBA-GEIGY contacted the Ocean County Department of Health to obtain a list of Oak Ridge neighborhood residents who have irrigation wells. In August of 1986, CIBA-GEIGY conducted a door-to-door survey in an area which included the are of known ground-water contamination plus

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a four block buffer zone to the south. Fourteen irrigation wells were located in this area; no domestic wells were found. Samples were taken from 11 wells for analysis. Three wells were not sampled by CIBA-GEIGY, however, as two wells were not operational and one homeowner located in the southern most portion of the buffer zone refused to have his well sampled. CIBA-GEIGY offered to seal the wells or to periodically test those wells which suggested evidence of contamination (see Appendix B).

Of the irrigation wells sampled by CIBA~GEIGY, only three exceeded standards or proposed standards established by the USEPA under· the Safe Drinking Water Act (20 Cadillac Dr.; 8 Hummingbird La.; and 11 Jordan Dr.). The homeowners at 20 Cadillac Drive accepted CIBA-GEIGY's offer and his irrigation well was sealed. Although arrangements have not yet been made for closure of the other two irrigation wells, the residents at 8, Hummingbird Lane have reportedly not used the well since 1985. The residents at 11 Jordan Drive reportedly use the irrigation well only for lawn watering via an in-ground sprinkler system .

Therefore, since no sampled irrigation wells which exceed USEPA existing or proposed drinking water standards for organic chemicals are being used for body-contact domestic purposes (drinking, cooking, bathing, swimming pools, etc.), ENVIRON did

not conduct a risk assessment associated with the use of irrigation wells. It is expected that the risks associated with the use of the irrigation well at 11 Jordan Drive, for example, are exceedingly small (e.g., incidental skin contact or inhalation of vapors during lawn watering), considerably less than the risks of exposure in the marshland area and the Toms River. Furthermore, ENVIRON believes that the steps that CIBA-GEIGY is taking, as outlined in Appendix B, will effectively preclude future exposure from wells in the Oak Ridge Subdivision area to potentially contaminated ground water.

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Figure 6

Steps in Hazardous Waste Site Public Health Risk Assessment Methodology

1. Review History of Site Operations and Available Monitoring Data

. 2. Identify Chemicals of Concern

3. Evaluate Toxicity Data on Identified Chemicals of Concern

4. Develop ADis (acceptable daily intakes for noncarcinogens and noncarcinogenic chronic effects of carcinogens) and UCRs (unit cancer risks for carcinogens)

5. Develop Exposure Scenarios and Estimate Resultant Human Intake

6.

7.

Calculate NUmerical Estimates of Risk on the Basis of Estimated Human Intake and ADis and UCRs

Collect Any Additional Monitoring Data Required to Verify Initial Risk Estimates.

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associated with the site {both on-site and off-site), the specific contaminants involved, and to estimate the potential for migration of these contaminants .

Because of the large number of chemicals often associated with a chemical waste site, it is sometimes necessary to limit the number of chemicals considered in assessing potential public health risk. Thus, in the second step of the assessment, "indicator" or "marker" chemicals may be selected from among the chemicals identified in environmental samples. The selection of such chemicals is often limited to those detected in ground water, surface, or soil samples and their inherent toxicities. Additional factors to be considered include physical and chemical parameters related to the chemicals' environmental mobility and persistence.

In the present risk assessment, ENVIRON has modeled exposures only for those chemicals detected at or above the published detection limit for the EPA designated method analysis. Monitoring data used in this analysis included sediment and surface water data from the marshland area, ground-water monitoring data for wells adjacent the Toms River, and river sediment data. These data were collected by the NUS Corporation, as part of the on-going USEPA Superfund remedial investigation {RI) of the TRP, by SR Analytical under the direction of AWARE, and by JTC Environmental Consultants under the direction of ENVIRON. These programs included analyses for volatile organic chemicals, acid extractable organic chemicals, and base/neutral extractable organic chemicals. In addition, volatile organic air and water monitoring data collected by Radian Corporation in the marshland area were used in the risk assessment as described below in step seven.

It should be emphasized that ENVIRON has based this risk assessment on only those chemicals both identified and quantified using currently accepted procedures. Further quantitative and qualitative analyses are required to identify remaining chemicals known to be present in environmental samples. Thus, this risk assessment is a preliminary

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conditions of human exposure. They also adjust for variability in susceptibility in the human population and for general imprecision in extrapolating from laboratory animals to humans. This procedure for development of an AD! may also be applied to chronic noncarcinogenic risks associated with carcinogens.

In contrast to noncarcinogens, carcinogens are thought by some investigators to pose some risk at any exposure levels. Although the size of the risk declines with decreasing exposure, under the "no-threshold" hypothesis the risk becomes zero only at zero exposure. The "no-threshold" assumption for carcinogens. is based on some current theories about the carcinogenic process and has generally been adopted by federal agencies as a conservative practice to protect public health. Despite the hypothetical nature of the "no-threshold" concept, in keeping with the conservative public health practices of the federal agencies, we have adopted the "no-threshold" hyPothesis for all carcinogens treated in this report. We recognize that this assumption may be incorrect for some carcinogens.

Scientists have developed several mathematical models to estimate, by extrapolation, low-dose carcinogenic risks to humans from observed high-dose toxicity typically found in experimental animal studies. The result of applying these models to carcinogenicity data is an estimate of the upper limit on lifetime risk per unit of dose (unit cancer risk or UCR). The mathematical model used by USEPA (and by ENVIRON in this risk assessment) - to generate a UCR for extrapolating carcinogenic response from high doses to low doses - is the linearized multistage model. This model estimates the upper limit on lifetime risk per unit of dose and provides a "conservative" estimate of risk, i.e., the model is likely to overestimate the actual UCR for a carcinogen. There are several alternative models that may fit experimental data as well as the USEPA model, but which generally predict lower risks in the low dose region, sometimes by several orders of magnitude. As in the adoption of the "no-threshold" hypothesis,

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we have adopted the USEPA model to ensure a conservative {public health protective) estimate of the UCR. The actual UCRs for many of the carcinogens are likely lower than predicted UCRs, and may be zero for some.

The result of the fourth step of this risk assessment was therefore the development of ADis for noncarcinogens and carcinogens and UCRs for carcinogens. In cases where USEPA had already developed and published an ADI or UCR for a chemical, these values were used by ENVIRON in the risk assessment. For chemicals without a published ADI {carcinogens and noncarcinogens), ENVIRON has calculated an ADI. In addition, for some chemicals, ENVIRON has calculated and used a more conservative ADI or UCR than th~ values published by USEPA if more relevant or up-to-date data was found; sources of ADis and UCRs are indicated in Tables 1 and 6, Appendix F. ENVIRON has prepared toxicity profiles which review available toxicity and dose-response data on each identified chemical. These toxicity profiles are presented in Appendix D.

In the fifth step of the risk assessment process, hypothetical exposure scenarios are developed which are specific to the site of concern. In the present assessment, such scenarios were constructed to represent the upper bound of reasonably foreseeable exposures to various contaminated media (air, soil, water) by a number of subgroups of the local population. Such scenarios are likely to provide the basis for risks which are more likely to represent the upper bounds of exposure and therefore be overestimates rather than underestimates, of actual risk. These scenarios account for the duration of exposure, the route of exposure, and the amount of chemical absorbed into the body, as well as the characteristics of the exposed population.

The result of step five is the estimation of the total intake of each contaminant a person would receive as a result of exposure under the conditions described by each scenario. The exposure scenarios developed in this risk assessment are described in greater detail in Appendix E .

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In the sixth step of the risk assessment process, numerical estimates of risks are calculated for each chemical by each potential route. of exposure, on the basis of the ADis and UCRs (step four) and the human intakes estimated for each exposure scenario (step five). Such estimates represent the public health risks which are postulated to result from exposure to the chemical, at the detected concentrations, under the cited scenario conditions. In the case of noncarcinogens and carcinogens, the estimated human intake is multiplied by the detected concentration to determine the average daily dose (ADD). The numerical estimate of risk is determined by dividing the ADD (in mg/kg/day) by the acceptable daily intake (AD!, in mg/kg/day): if the ADD/ADI ratio does not exceed 1.0, then no adverse health effects would be expected to occur under

-those conditions of exposure. In the case of carcinogens, the estimated lifetime human intake is multiplied by the detected concentration to determine the lifetime average daily dose (LADD). The LADD, (in mg/kg/day) is multiplied by the UCR (in [mg/kg/day]-1 ) to calculate an upper-bound, lifetime cancer risk. A lifetime increased cancer risk of one-in-one-million (10- 6 ) indicates that one new case of cancer per lifetime would be expected for every one million people exposed to that concentration of contaminant under the assumed exposure conditions, and if all the other conservative assumptions

adopted in the risk assessment method used are correct. Since it is extremely unlikely that these exposures will be reached in all individuals and that any of the other assumptions are correct for all individuals, it is almost certain that the true risk will be lower than 10-6 and may actually be zero for some substances. Ratios of ADD/ADI for noncarcinogens and carcinogens and upper-bound, lifetime cancer risks for carcinogens are presented in Tables 3 and 8, Appendix F.

Under the scenarios developed in this risk assessment, there were several cases in which individuals were postulated to have potential simultaneous exposure to more than one contaminated medium (e.g., a child playing in the marshland

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area who ingested and was dermally exposed to contaminated surface water and who also ingested and was dermally exposed to contaminated soil). In such cases, in order to verify that the ADD/ADI ratios or estimates of upper-bound, lifetime cancer risk were sufficiently protective of public health, the following procedure was undertaken. First, the doses which would result from exposure to the maximum concentration in each medium (air, water, soil) were calculated. In the case of noncarcinogens and noncarcinogenic effects of carcinogens, the average daily dose for each scenario was di~ided by the ADI and the resultant ratios were summed. If the sum of the ratios was 1.0 or less, no adverse health effects would be expected to occur from the combined pathways of exposure. For carcinogens, upper-bound, lifetime cancer risks were estimated based on lifetime average daily doses for each potential route of exposure, and the resultant risks were similarly summed. Sums

• of ADD/ADI ratios and of upper-bound, lifetime cancer risk are presented in Tables 4, 5, 9, and 10 of Appendix F.

In the seventh step of the risk assessment process, additional data required to verify the accuracy of calculated exposure estimates critical to the risk assessment process are collected. In this study, the greatest uncertainty surrounded estimates of potential air concentrations in the marshland areas of the Toms River. Therefore, ENVIRON directed Radian Corporation to conduct an ambient air monitoring program in the marshland area during September ll and 12, 1986 (see Appendix H). These data were then used to verify preliminary risk estimates which were based solely on calculated air contaminant concentrations in the marshlands.

The methodology for conducting a public health risk assessment followed here is consistent with methods developed by the National Academy of Sciences (NRC 1983) and by USEPA in their Superfund Public Health Evaluation Manual (USEPA 1985b). (Detailed descriptions of Steps 3, 4, 5, and 6 of this risk assessment methodology are presented in Appendix C).

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V. POPULATIONS POTENTIALLY SUBJECT TO EXPOSURE

The following section provides a detailed description of the local population and activities in the area of the TRP site. · Potential receptors and exposure pathways associated with contamination from the site are identified. These receptors and pathways are detailed in Appendix E.

A. Marshland Area of Winding River Park Winding River Park, a Green Acres site maintained by Dover

Township, is a recreational complex providing public access to playground and picnic facilities, extensive hiking and bicycling paths and canoeing in the Toms River. (Recreational activities associated with the Toms River are discussed in Section V.B.) A plume of contaminated ground water is migrating from the TRP toward the Toms River, discharging, in part, as ground-water "seeps" in the marshland area on the western bank of the Toms River, within the Park and adjacent to the Oak Ridge Subdivision (see Figure 1). Children are believed to play in this area and therefore might be exposed to contaminants through inhalation of contaminated air, contact with and ingestion of contaminated soil and surface water. In this risk assessment, ENVIRON addressed these routes of potential exposure for a nine-year-old child (average of ages six to twelve). The characteristics of this receptor are discussed in Appendix E and Table 2, Appendix F.

B. The Toms River

1. Recreational Uses of the Toms River The recreational us·es of the Toms River include

bathing, boat and bank fishing and crabbing, canoeing, sailing and power boating, water skiing and additional bank uses such as concerts, picnicking and hunting. There are private campgrounds along the river, as well as public

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parks and conservation lands. The recreational uses may be broadly divided according to the upper and lower sections of the river .

The upper portion of the Toms River is also known as Winding River; Winding River Park is located between Oak Ridge Parkway (Route 527) and Route 37 and contains this section of the river. Trout are stocked by the State of New Jersey, in the Toms River above Route 37. Within the park are playground facilities, barbeque pits and picnic tables, extensive hiking trails and a constructed bikepath. Canoeing, fishing, indoor skating, and equestrian activities also take place in the park. Dermal contact with and accidental ingestion of water and soil in the Toms River were identified as potential routes of exposure for children playing along ~he river, and for recreational fisherman at the river. Inhalation of volatile compounds while playing or fishing at the river was also identified as a potential route of exposure. In the risk assessment, ENVIRON addressed these routes of ·potential. exposure for a nine-year-old child (average of ages six to twelve) and an adult male. The characteristics of these receptors are discussed in Appendix E and Table 7, Appendix F.

Approximately three miles downstream from the TRP, at the wider tidal areas of the river, there are extensive power boating and fishing. While freshwater fishing is limited due to the influx of salt water, there are marine fishing and crabbing near the mouth of the river. Five communities have beach facilities along the wider reaches of the Toms River: Ocean Gate, Pine Beach, Dover Township, Beachwood and Island Heights. As only one contaminant (i.e., trichloroethylene) has been identified in the river adjacent to the TRP, exposures to contaminants from the TRP at the wider, downstream area of the Toms River were not considered to be reasonable

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scenarios. Moreover, the beach facilities are 2 to 6 miles from the TRP, and therefore such exposures are not considered in this risk assessment .

2. Ingestion of Fish from the Toms River Ingestion of fish from the Toms River was identified

as a potential route of exposure for local recreational fishermen and others who might consume the fish. In this risk assessment, ENVIRON addressed this route of potential exposure for a family comprised of an aault male, an adult female, a four-year-old child (average of ages two to six), a nine-year-old child (average of ages six to twelve), and a fifteen-year-old child (average of ages twelve to eighteen). The characteristics of these receptors are discussed in Appendix E and Table 7, Appendix F.

3. Potential Impacts of Withdrawals by the Toms River Water Company Computer simulation studies of the effects of pumping

indicate that the Toms River is an effective hydrogeologic barrier to the migration of contaminants to drinking water wells located east of the river. Both field data and model simulations show that the river exerts a major influence on aquifers in both the Cohansey and Kirkwood formations, drawing ground water toward the river from both the east and west. The Toms River Water Company (TRWC) well 20 is the municipal well closest to the Toms River and TRP. ENVIRON has performed an analysis, using computer simulation, to address the possible impact of contamination of the RI-9 area and the west side of the river on well 20. According to simulation results, the capture zone of the well extends less than 1000 feet in the direction of the river and beyond that point, flow continues to the river. Thus, the simulation shows that

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TRWC well 20 is far enough from the river that its maximum discharge is not sufficient to reverse the flow of ground water toward the river, either at RI-9 or on any other stretch of the river (ENVIRON, 1986).

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VI. IDENTIFICATION OF CHEMICALS OF CONCERN

A. Marshland Area of Samples of ground

October, 1985, as part

Winding River Park water collected in August, September of the ongoing USEPA remedial

and

investigation identified a plume of contamination migrating from the TRP toward the Toms River. This plume of contamination appears to discharge, in part, as ground-water "seeps" in the marshland area on the western bank of the river, within Winding River Park. The concern that·this area might be contaminated with volatile organ~c priority pollutants, and the belief that-children play in this area, prompted sampling of surface waters, soil (sediment), and the air in the marshland area.

The marshland area sampled on March 4, 1986, is located between the contours of highest total volatile priority pollutants, as identified in the iso-concentratiqn map prepared by AWARE, Incorporated (Figure 4). The sediment and surface water sampling locations are shown in Figure 5. Six sediment samples and three surface water samples were collected from an area north of a muddy stream bed and defined by an area of surface water pending. Collection and analysis of samples were performed by JTC Environmental Consultants (JTC), under the direction of ENVIRON Corporation. The maximum soil and water ·concentrations detected are shown in Appendix A and in Table 1, Appendix F.

Air contaminant concentrations in the marshland area were initially estimated from the maximum concentrations found in surface water samples using a box model (Baynes 1986, Appendix G). The model assumes that contaminants are uniformly mixed within the box and that the (human) receptor remains within the defined area for the duration of exposure. The top of the box (mixing height) was defined by determining the trajectory of a release occurring at the upwind edge of the marsh area. The model assumed an average summer water temperature of 22.3°C (72.2°F), no lateral dispersion, and a wind speed of 0.8

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m/second. The contaminant concentrations in the air over the marshland area calculated using this model are listed in Table 1, Appendix F .

Further sampling of the marshland area was undertaken on September 11 and 12, 1986 by Radian Corporation under the direction of ENVIRON to collect data on ambient concentrations of volatile organic compounds (VOCs) in the marsh air and to validate the applicability of the box model described above. Since chloroform, benzene, trichlorobenzene and chlorobenzene were found to be the major contributors to the risk from potential exposure to contaminants in the marsh, emphasis of the field sampling program was only on determining concentrations of the VOCs in ambient air and surface water. Meteorological data were also monitored during sampling to collect site-specific data as input to the model. After validation of the model, air concentrations were calculated for summer conditions (assuming a conservative water temperature of 25°C) and are presented in Table 2, Appendix G. Appendix H ::.·...:mmarizes results of Radian's sampling of the marshland area and Appendix G presents the validation of the box model .

B. The Toms River The risk assessment for exposures in the Toms River

between RI-9 and the southern perimeter of the contaminant plume is based on estimation of contaminant concentrations from ground-water samples. The procedures to estimate mass loading of each contaminant to the river, and subsequent dilution of concentrations after entering the river, are described below.

The first step in this process was to characterize the ground-water quality at various points along the river where ground water discharges into the river. Samples of ground water from twenty-four monitoring wells closest to the river were included in this analysis. Twenty-three wells are located ~n the TRP side of the river (western side of the river) and one well (RI-9) is located on the eastern side of the river. Table 2 presents a list of the twenty-four wells. Monitoring

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TABLE 2

Ground-Water Wells Used to Estimate Contaminant Loading to the Toms River

RI-28

RI-29

RI-17

115

124

125

126

127

128

129

136

71

RI-15

RI-14

RI-5

RI-4

TP4

RI-1

169

170

171

172

173

RI-9

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well RI-9 was included since contaminated ground water, in the area of RI-9, has been shown to pass underneath the river and discharge to the river from the eastern side .

Ground-water quality data from each monitoring well were reviewed and thirty chemicals were identified at co~centrations above the detection limit; these chemicals were presented in Appendix A and are listed in Table 6, Appendix F.

The maximum concentration of each contaminant detected in each well was chosen to represent the maximum concentration of each contaminant in the ground water entering the river at that point. In choosing these values, the following assumptions were made .. If a well is screened in two formations, it is assumed that contaminated ground water from both formations enters the river and a maximum concentration for each contaminant of concern was identified for each formation. If a well is screened twice in the same formation, the maximum concentration reported was chosen to represent the water quality of the formation. In addition, as certain pairs of wells (i.e~, 124/125, 126/127, 128/129, 75/RI-7, and 73/RI-6) are located very close to each other, the maximum concentration at either well in the pair is chosen to represent the conditions at both wells. For the RI-9 area, it was assumed that any contamination observed at well RI-17 (which is screened in the Primary Cohansey Formation) discharges to the river from the TRP (western) side of the river. Thus, for well RI-17 the maximum concentration for each contaminant of concern was identified. It has been shown that in the RI-9 area contamination occuring in the Lower Cohansey formation in the western side of the river (represented by well 115 screened in the Lower Cohansey) passes underneath the river and enters the river from the Primary Cohansey formation on the eastern side of the river (represented by well RI-9). Thus, the maximum concentration at either well 115 or well RI-9 is identified to represent the conditions in the Lower Cohansey. Table 3 presents the maximum concentration chosen for each well and contaminant .

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Input Values and Calculated Mass loadings to the Toms River

CHEMICAL CONCENTRATION LENGTH DEPTH PERMEABIL TV HYDRAULIC MASS INPUT WELL NAME (ppb) ( ft) ( ft) (cm/s) GRADIENT (cfs x ppb)

RI-1S ACETONE 68 300 24 0.043 0.004 2.763 RI-14D ACETONE 198 500 38 0.043 0.004 21.229 RI-28D ACETONE 264 650 37 0.043 0.004 35.829 RI-150 ACETONE 480 850 30 0.043 0.004 69.071 Rl-40 ACETONE 24 500 30 0.043 0.004 2.031 RI-29D ACETONE 65 1050 32 0.043 0.004 12.324 RI-15S ACETONE 305 850 16 0.043 0.004 23.407 Rl-17 ACETONE 150 700 20 0.043 0.004 11 .850 RI-4S ANILINE 5 500 7 0.043 0.004 0.099 128 ANILINE 62 300 21 . 0.043 0.004 2.204 Rl-40 ANILINE 62 500 30 0.043 0.004 5.248 115 ANILINE 16 700 28 0.043 0.004 1. 770 RI-5D BENZENE 13 500 33 0.043 0.004 1.210 RI-4D BENZENE 18 500 30 0.043 0.004 1.524 RI-15D BENZENE 11 850 30 0.043 0.004 1.583 TP4-D BENZENE 110 500 25 0.043 0.004 7.759 115 BENZENE 110 700 2B 0.043 0.004 12.166 RI-17 BENZENE 38 700 20 0.043 0.004 3.002 RI-17 CARBON DISUlfiDE 12 700 20 0.043 0.004 0.948 RI-1XD CARBON DISUlfiDE 25 300 24 0.043 0.004 1.016 RI-14S CARBON DISUlfiDE 18 500 38 0.043 0.004 1.930 RI-15D CARBON DISUlfiDE 3 850 30 0.043 0.004 0.432 RI-4D 4-CHLOROANILINE 17 500 30 0.043 0.004 1.439 Rl-45 4-CHLOROANILINE 5 500 7 0.043 0.004 0.099 RI-50 4-CHLOROANILINE 10 500 33 0.043 0.004 0.931

('l 128 CHLOROBENZENE 110 300 21 0.043 0.004 3.911 .... RI-50 CHLOROBENZENE 470 500 33 0.043 0.004 43.762 at RI-9 CHLOROBENZENE 1800 700 28 0.043 0.004 199.087

Rl-17 CHLOROBENZENE 180 700 20 0.043 0.004 14.220 a Rl-45 CHLOROBENZEN£ 300 500 7 0.043 0.004 5.925 a 715 CHLOROBENZENE 22 950 34 0.043 0.004 4.010 ~ Rl-40 CHLOROBENZEN£ 2740 500 30 0.043 0.004 231.929

RI-15D CHLOROBENZENE 230 850 30 0.043 0.004 33.096 ... TP4-D CHLOROBENZEN£ 1600 500 25 0.043 0.004 112.861 ...., RI-40 BIS(2-CHLORO£THYL)£TH£R 13 500 30 0.043 0.004 1.100 Cl' '-0

- • - -·- -· Table 3

Input Values and Calculated Mass loadings to the Toms River

CHEMICAL CONCENTRATION LENGTH DEPTH PERMEABIL TV HYDRAULIC HASS INPUT WEll NAME (ppb) ( ft) ( ft) (cm/s) GRADIENT ( cfs x ppb)

TP4-A CHLOROFORM 240 500 25 0.043 0.004 16.929 RI-140 CHLOROFORM 4 500 38 0.043 0.004 0.429 RI-15S CHLOROFORM 2 850 16 0.043 0.004 o. 153 RI-50 CHLOROFORM 91 500 33 0.043 0.004 8.473 Rl-150 CHLOROFORM 52 850 30 0.043 0.004 7.483 RI-1S CHLOROFORM 2 300 24 0.043 0.004 0.081 RI-40 2-CHLOROPHENOL 12 500 30 0.043 0.004 1.016 128 CHLOROTOLUENE 17 300 21 0.043 0.004 0.604 128 1,2-0ICHLOROBENZENE 37 300 21 0.043 0.004 1.315 RI-50 1,2-0ICHLOROBENZENE 247 500 33 0.043 0.004 22.998 124 1,2-0ICHLOROBENZENE 89 500 20 0.043 0.004 5.022 RI-5S 1,2-0ICHLOROBENZENE 2 500 18 0.043 0.004 o. 102 RI-40 1,2-0ICHLOROBENZENE 121 500 30 0.043 0.004 10.242 TP4 1,2-0ICHLOROBENZENE 72 500 25 0.043 0.004 5.079 RI-4S 1,2-0ICHLOROBENZENE 25 500 7 0.043 0.004 0.494 RI-150 1,2-0ICHLOROBENZENE 101 850 30 0.043 0.004 14.534 RI-4S 1,3-0ICHLOROBENZENE 4 500 7 0.043 0.004 0.079 Rl-40 1,3-0ICHLOROBENZENE 20 500 30 0.043 0.004 1.693 RI-50 1,3-0ICHLOROBENZENE 3 500 33 0.043 0.004 . 0.279 RI-4S 1,4-0ICHLOROBENZENE 2 500 7 0.043 0.004 0.040 RI-4D 1,4-0ICHLOROBENZENE 11 500 30 0.043 0.004 0.931 128 1,4-0ICHLOROBENZENE 20 300 21 0.043 0.004 0.711 RI-150 1,4-0ICHLOROBENZENE 11 850 30 0.043 0.004 1.583 RI-50 1,4-0ICHLOROBENZENE 18 500 33 0.043 0.004 1.676 RI-150 1,2-0ICHLOROETHANE 6 850 30 0.043 0.004 0.863 RI-9 1,1-0ICHLOROETHYLENE 8 700 28 0.043 0.004 0.885

C1 RI-11 T-1,2-0ICHLOROETHYLENE 46 700 20 0.043 0.004 3.634 .... RI-4S T-1,2-0ICHLOROETHYLENE 240 500 7 0.043 0.004 4.740 al Rl-9 T-1,2-0ICHLOROETHYLENE 580 700 28 0.043 0.004 64.150

RI-40 T-1,2-0ICHLOROETHYLENE 725 500 30 0.043 0.004 61.368 CSJ RI-150 T-1,2-0ICHLOROETHYLENE 43 850 30 0.043 0.004 6.188 C5J 128 T-1,2-DICHLOROETHYLENE 5 300 21 0.043 0.004 o. 178 .. RI-50 T-1,2-DICHLOROETHYLENE 70 500 33 0.043 0.004 6.518

TP4-D T-1,2-DICHLOROETHYLENE 190 500 25 0.043 0.004 13.402 ... TP4-D DICHLOROMETHANE 11 500 25 0.043 0.004 0.776 -..1 -..1 CSJ

·- -·- -· -----··

Table 3

Input Values and Calculated Mass Loadings to the Toms River

CHEMICAL CONCENTRATION LENGTH DEPTH PERMEABIL TV HYDRAULIC MASS INPUT WELL NAME (ppb) ( ft) ( ft) (cm/s) GRADIENT (cfs x ppb)

RI-15D DICHLDROMETHANE 2800 850 30 O.D43 0.004 402.913 RI-40 OICHLOROMETHANE 17 500 30 0.043 0.004 1.439 RI-lXO OJ CHLOROMETHANE 9 300 24 0.043 0.004 0.366 RI-15D 1,2-DICHLOROPROPANE 3 850 30 0.043 0.004 0.432 RI-9 1,2-DICHLOROPROPANE 23 700 28 0.043 0.004 2.544 RI-4D ETHYL BENZENE 23 500 30 0.043 O.DD4 1.947 128 ETHYLBENZENE 6 300 21 0.043 0.004 0.213 115 HEXACHLOROETHANE 14 700 28 0.043 0.004 1.548 Rl-50 NAPHTHALENE 23 500 33 0.043 0.004 2.142 TP4-A NAPHTHALENE 6.9 500 25 0.043 0.004 0.487 128 NAPHTHALENE 14 300 21 0.043 0.004 0.498 124 NAPHTHALENE 86 500 20 0.043 0.004 4.853 RI-40 NAPHTHALENE 52 500 30 0.043 0.004 4.402 TP4 NITROBENZENE 18 500 25 0.043 0.004 1.270 RI-40 N-NITROSOOIPHENYLAHINE 2 500 30 0.043 0.004 0.169 128 PHENOL 12 300 21 O.D43 0.004 0.427 RI-9 1,1,2,2-TETRACHLOROETHANE 58 700 28 0.043 0.004 6.415 R1:..11 1,1,2,2-TETRACHLOROETHANE 27 700 20 0.043 0.004 2.133 TP4 1,1,2,2-TETRACHLOROETHANE 22 500 25 0.043 0.004 1.552 RI-4S TETRACHLOROETHYLENE 10 500 7 0.043 0.004 o. 198 Rl-50 TETRACHLOROETHYLENE 122 500 33 0.043 0.004 11.359 RI-150 TETRACHLOROETHYLENE 43 850 30 0.043 0.004 6.188 TP4-0 TETRACHLOROETHYLENE 180 500 25 0.043 0.004 12.697 Rl-40 ·TETRACHLOROETHYLENE 18 500 30 0.043 0.004 1.524 Rl-lXO TOLUENE 14 300 24 0.043 0.004 0.569

C'1 RI-9 TOLUENE 4 700 28 0.043 0.004 0.442 .... RI-15S TOLUENE 8 850 16 0.043 0.004 0.614 tD Rl-40 TOLUENE 27 500 30 0.043 0.004 2.285

Rl-50 TOLUENE 4 500 33 0.043 0.004 0.372 sa RI-150 TOLUENE 10 850 30 0.043 0.004 1.439 Q Rl-140 TOLUENE 13 500 38 0.043 0.004 1.394

• RI-4S 1,2,4-TRICHLOROBENZENE 17 500 7 0.043 0.004 0.336 RI-150 1,2,4-TRICHLOROBENZENE 18 850 30 0.043 0.004 2.590 ... RI-50 1,2,4-TRICHLOROBENZENE 74 500 33 0.043 0.004 6.890

~ TP4 1,2,4-TRICHLOROBENZENE 134 500 25 0.043 0.004 9.452 ~ ...

--·- - --·-

Table 3

Input Values and Calculated Mass Loadings to the Toms River

CHEMICAL CONCENTRATION LENGTH DEPTH PERHEABILTY HYDRAULIC MASS INPUT WELL NAME (ppb) ( ft) ( ft) (cm/s) GRADIENT (cfs x ppb)

Rl-40 1,2,4-TRICHLOROBENZENE 102 500 30 0.043 0.004 8.634 RI-9 1,1,2-TRICHLOROETHANE 7 700 28 0.043 0.004 0. 774 71S TRICHLOROETHYLENE 10 950 34 0.043 0.004 1.823 RI-40 TRICHLOROETHYLENE 14 500 30 0.043 0.004 1.185 115 TRICHLOROETHYLENE 25000 700 28 0.043 0.004 2765.092 RI-4S TRICHLOROETHYLENE 53 500 7 0.043 0.004 1.047 RI-50 TRICHLOROETHYLENE 104 500 33 0.043 0.004 9.683 Rl-l4S TRICHLOROETHYLENE 8 500 38 0.043 0.004 0.858 RI-15D TRICHLOROETHYLENE 61 850 30 0.043 0.004 8.778 Rl-17 TRICHLOROETHYLENE 1000 700 20 0.043 0.004 79.003 TP4-0 TRICHLOROETHYLENE 1800 500 25 0.043 0.004 126.969 RI-45 TRICHLOROPROPANE 18 500 7 0.043 0.004 0.356 RI-17 TRICHLOROPROPANE 137 700 20 0.043 0.004 10.823 TP4 TRICHLOROPROPANE 65 500 25 0.043 0.004 4.585 RI-9 TRICHLOROPROPANE 1500 700 28 0.043 0.004 165.906 Rl-50 TRICHLOROPROPANE 87 500 33 0.043 0.004 8. 101 RI-150 TRICHLOROPROPANE 45 850 30 0.043 0.004 6'.475 RI-40 TRICHLOROPROPANE 10 500 30 0.043 0.004 0.846 Rl-50 VINYL CHLORIDE 5 500 33 0.043 0.004 0.466 RI-150 VINYL CHLORIDE 3 850 30 0.043 0.004 0.432 RI-40 XYLENES 12 500 30 0.043 0.004 1.016 RI-140 XYLENES 5 500 38 0.043 0.004 0.536 128 XYLENES 8 300 21 0.043 0.004 0.284 RI-150 XYLENES 3 850 30 0.043 0.004 0.432

0 .... Ul

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As stated previously, it was assumed that the concentrations observed at the wells listed in Table 2 represent the conditions of the contaminant plume as it enters the river; although, in some cases the wells are located 400 to 500 feet from the river.

The second step in the assessment is to estimate the mass loading into the river of each of the identified chemicals. This mass loading can be calculated by:

M = Oc (1)

where: M =mass loading of contaminant into the river (cfs-ppb); 0 =volumetric flow rate of the ground water {ft3/sec);

and c =contaminant concentration in the ground water {ppb).

The volumetric flow rate of the ground water can be calculated from Darcy's Law:

0 = KiA where: K =permeability (em/sec);

i = hydraulic gradient; and A = cross-sectional area through

(ft2). which flow occurs

{2)

The approach taken to calculate the total mass loading of each contaminant of concern to the river was to first segment the river into 23 sections. These sections are based on the location of the ground-water monitoring wells, with each section represented by a ground-water well at its center. The mass loading for each contaminant from each section is calculated using equations 1 and 2. The total mass loading for each contaminant into the river is then calculated by summing the contribution of each section.

As can be seen from equations 1 and 2, the mass loading is the product of the contaminant concentration, permeability,

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hydraulic gradient, and cross-sectional area. The values for the contaminant concentrations at each well are presented in Table 3. A value of 0.043 cm/s was used to represent the permeability; this value is currently considered by AWARE (1986) as a representative value·of the Primary and Lower Cohansey formations. A value of 0.004 is used to represent the hydraulic gradient. This value is conservative and is based on ENVIRON's computer simulations and field observations which suggest that the hydraulic gradient near the river varies from 0.003 to 0.004.

Finally, the cross-sectional area is calculated as the product of the length of the section associated with each well and the thickness of the formation in which the well is screened. The length associated with each well was calculated as the average distqnce between the well and its two adjacent wells. For example, well RI-5 is approximately 600 feet from RI-14 and 400 feet from RI-4. The section length chosen to be represented by well RI-5 is thus the average of 600 and 400 feet, or 500 feet. The section length associated with a well located at the northernmost or southernmost part of the site was calculated as half the distance between the well and its one adjacent well. The thickness of the formation associated with each well was determined by reviewing cross-sectional data from AWARE (1986). Assumptions used in compiling the thickness of the formation values are: 1) the black organic sand was not an aquitard, and 2) where present, the yellow clay/black sand layer did confine the Primary Cohansey. The thickness of the formation discharging contaminated ground water to the river beneath piezometer TP-4 was assumed to be equal to 25 feet. This value corresponds to the depths of the formation observed in wells adjoining TP-4, e.g., RI-4 at 30 feet, and RI-1 at 24 feet.

Table 3 presents the values for the concentration, permeability, hydraulic gradient, depth and length and the calculated mass loadings for each representative section length. These mass loadings were summed, by chemical, to arrive at the

total mass loading for each chemical. These total mass loadings were used in the dilution analysis .

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CIS 004 1774

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The third and final step in estimating concentrations of contaminants in the Toms River was to perform dilution calculations on the mass loadings entering the river. If the upstream river concentration of contamination is assumed to be zero (i.e., no upstream contribution) and complete mixing is assumed, then the river contaminant concentration after mixing upstream river water with ground water can be expressed as:

Co =

where Co =

M =

Ou = Ogw =

M (3) Ou + Ogw

river contaminant concentration after mixing upstream river water with ground water;

mass loading of contaminant into the river;

upstream Toms River flow; and

ground-water flow entering Toms River at the CIBA-GEIGY Toms River plant.

Qu was assumed to be equal to 215 cubic feet per second (cfs), which is the average river flow or 64 cfs which is the seven-day, ten-year low flow, both of which were measured by the· United States Geological Survey at Toms River near the town of Toms River, New Jersey (USGS 1982). The gauging station is at the point where the Oak Ridge Parkway crosses the Toms River near the TRP. The average river flow value was used in all calculations for estimating river contaminants for the recreational fishing exposure scenarios, as fishing could occur year round. Low flow river values were used in all calculations for estimating river contaminants for the other exposure scenarios to the Toms River. ENVIRON recognizes the seven-day, ten-year low flow represents extreme conditions which would not be expected to persist during the assumed exposure periods or be representative of a chronic exposure period. However, if there is no significant risk under these conditions then it follows that no significant risk will exist under typical summer flow conditions. Finally, Qgw was assumed to be equal to 2 cfs (AWARE, 1986). As can be seen,

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Oqw has an insignificant effect on the dilution calculations. The contaminant concentrations at both average flow and seven-day, ten-year low flow are listed in Table 4 .

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CIS 004 1776

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VII. RISK CHARACTERIZATION

ENVIRON has assessed the present extent of off-site contamination with respect to the public health risks from potential exposures to the chemical contaminants from the TRP. ENVIRON specifically evaluated those potential exposure pathways that are believed to be the most significant for the populations potentially at risk (e.g., exposure to contaminated water in the marshland area of Winding River Park adjacent to the Oak Ridge Subdivision, recreational fishing at the Toms River). For potential exposure to noncarcinogens and for chronic noncarcinogenic risks of carcinogens, ADD/ADI ratios were calculated. For potential exposure to carcinogens, the upper-bound, lifetime cancer risks under each exposure scenario were calculated. These numerical estimates of risk were compared with generally accepted levels of risk to ascertain the potential for adverse public health effects. The focus of this risk assessment is on potential public health risks associated with TRP contaminants. In addition, potential environmental risks were addressed based on aquatic toxicity.

Information on actual conditions of exposure at the marshland area and at the Toms River is not readily available. In order to estimate potential health risks associated with the site, it consequently was necessary to develop specific exposure scenarios which model potential human exposure at these areas.

As a matter of prudent public health policy in its exposure scenarios, ENVIRON has chosen assumptions for the hypothetical scenarios about potential exposures that would generally be considered to represent upper-bound levels of reasonably foreseeable exposures (and would therefore overestimate risk). The scenarios modeled in this risk assessment are believed to be ones that could potentially occur for members of the population in the community surrounding the site. For instance, play in the marshland area of Winding River Park, which is relatively inaccessible to young children

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and has no organized or supervised recreational uses, is not anticipated for most individuals; however, it is not unreasonable to expect that some individuals (such as local children) might be regularly present in the marshland. In general, assumptions about potential conditions of exposure, while judged to be reasonable, are also expected to overestimate potential exposure and associated risk.

A similar approach has been taken with regard to the derivation of acceptable levels of exposure based on the toxicologic .properties of the detected chemicals. As described in Appendix C, conservative assumptions have been used in the derivation of risk estimates. These include the use of safety factors for deriving ADis for noncarcinogenic effects and conservative extrapolation models for estimating the potency of carcinogens. Thus, the conservative assumptions incorporated in this risk assessment, both in terms of exposure and the inherent toxicity of a chemical substance, tend to overestimate the true risks to the potentially exposed population from potential exposure to chemicals from the_ TRP.

The remainder of this section presents a description of each exposure scenario modeled in this risk assessment and the results of our evaluation for each scenario. The major assumptions used to model exposure are detailed in the exposure scenarios presented in Appendix E and are presented in Tables 2 and 7, Appendix F.

A. Marshland Area of Winding River Park Exposure of humans to the marshland area of Winding River .

Park is judged to be limited. There are presently no organized or supervised recreational uses of this area of the park. It is not unreasonable to assume, however, that children exploring the park may play in this area.

ENVIRON has considered a number of exposure scenarios and has chosen to model exposure to contaminants in marshland soil (as a result of unintentional soil ingestion and dermal absorption), exposure to contaminants in marshland surface

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waters (also as a result of unintentional water ingestion and dermal absorption), and inhalation of volatile organic chemicals. Because the marshland could be considered an inviting place for a child to play, potential exposure for a nine-year-old child was modeled.· Under these exposure . scenarios, it was assumed that children from around the ages of six to twelve (using a nine-year-old child as an average) could play in the marshland 210 times over a 7-year period (e.g., 2 times a week during the 15 warmer weeks of the year, for the 7 years from ages six to twelve). Children younger than six years of age are unlikely to be found playing away from home unattended.·

Estimated human intakes from each route were used to derive numerical estimates of risk for each exposure. If more than one route of exposure was identified, then total risk from exposure to the TRP contaminants identified in that medium was determined by summing the risks from each route of exposure (e.g., risk from accidental ingestion of soil and the risk from dermal absorption from soil).

l. Exposure to Soil Contaminants in the Marshland Area of Winding River Park-­Accidental Ingestion and Dermal Absorption

Exposure Scenario Exposure to soil contaminants in the marshland area

of Winding River Park was identified as a potential exposure pathway for the population in the surrounding community. Two potential pathways of exposure to soil contaminants were modeled--unintentional ingestion of soil and dermal absorption from soil.

In modeling accident~! ingestion of contaminated soil and sediment, it was assumed that a nine-year-old child could potentially ingest 100 mg of soil each time he played in the marshland area, and that 100% of ingested contaminants would be absorbed from the soil by the gastrointestinal tract. In modeling dermal absorption of

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soil contaminants, it was assumed that a child could expose half of his total body surface area to the soil and sediment each time he played in the area.

Dermal absorption was assumed to be less than 100% because of the barrier provided by the skin. On any given day, dermal absorption from soil was assumed to be 1% of that present in the soil on the skin surface for chemicals with a high K

0w (log K

0w greater than 4), based on a

conservative estimate using dermal absorption data by Poiger and Schlatter (1980). On any given day, dermal absorption for all other chemicals was assumed to be 10%. The dermal absorption coefficients and log K

0ws for all

the chemicals evaluated for the TRP are in Tables 1 and 6, Appendix F.

For a more complete description of the exposure scenarios modeling accidental ingestion of contaminated soil in the marshland area of Winding River Park, see Appendix E, Scenarios A (for carcinogens) and AA (for noncarcinogens). For the exposure scenarios that mod~l dermal absorption from contaminated soil in the marshland area, see Appendix E, Scenarios B (for carcinogens) and BB (for noncarcinogens). For numerical estimates of risk derived from the detected soil contaminant concentrations under the exposure conditions of these scenarios, see Appendix F, Tables 3, 4, and 5.

Assessment of Risks Several organic chemicals were identified in sediment

samples from the marshland area of Winding River Park. None of these chemicals were present at levels which, under the modeled exposure scenarios, resulted in ADD/AD! ratios which exceeded 1.0. On the basis of this analysis, potential exposure from accidental ingestion of soil contaminants or dermal absorption of contaminants from soil -- either alone or as the combination of both routes of exposure -- is not expected to result in any adverse

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CIS 004 1780

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effects. It should be noted that ADD/ADI ratios were calculated for exposure to noncarcinogens and for chronic noncarcinogenic effects of carcinogens .

Upper-bound, lifetime cancer risks due to exposure to the carcinogens identified in marshland soil did not

-8 exceed 10 for either exposure scenario. The total risk associated· with accidental ingestion plus dermal absorption did not exceed 10-8 .

2. Exposure to Surface Water Contaminants in the Marshland Area of Winding River Park-­Accidental Ingestion and Dermal Absorption

Exposure Scenario Exposure to surface water contaminants in the

marshland area of Winding River Park was identified as a potential exposure pathway for the population in the surrounding community. Two potential pathways of exposure to surface water contaminants were modeled--unintentional ingestion of water and dermal absorption from surface water .

In modeling accidental ingestion of surface water, it was assumed that a nine-year-old child could potentially ingest 5 ml of surface water each time he played in the marshland area, and that 100% of ingested contaminants would be absorbed from the water by the gastrointestinal tract. In modeling dermal absorption of surface water contaminants, it was assumed that a child could expose half of his total body surface area to the surface water and sediment each time he played in the area.

Dermal absorption of chemicals from water was assumed to be greater for chemicals with a higher affinity for hydrophobic media than for water (as conservatively indicated by an octanol-water partition coefficient,

Kow' greater than 104 , or a log K0 w greater than 4). This assumption was made because skin exhibits hydrophobic properties and is a less effective barrier to

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more lipid soluble chemicals. The conservative assumption was made that, on any given day, dermal absorption from water for chemicals with a log K greater than 4 is 50% ow -of that present in water on the skin surface based on dermal absorption data by Poiger and Schlatter (1980), and that dermal absorption for all other chemicals is 10\. The dermal absorption coefficients and log K

0ws for ~11

the chemicals evaluated for TRP are in Tables 1 and 6, Appendix F.

For a more complete description of.the exposure scenarios modeling accidental ingestion of contaminated surface waters in the marshland area of the Winding River Park, see Appendix E, Scenarios c (for carcinogens) and cc (for noncarcinogens). For the exposure scenarios that model dermal absorption from contaminated surface water in the marshland area, see Appendix E, Scenarios D (for carcinogens) and DD (for noncarcinogens). For numerical estimates of risk derived from the detected surface water contaminant concentrations under the exposure conditions of these scenarios, see Appendix F, Tables 3, 4, and 5.

Assessment of Risks Several organic chemicals were identified in surface

water samples from the marshland area of Winding River Park. None of these chemicals were present at levels which, under the modeled exposure scenarios, resulted in ADD/ADI ratios which exceeded 1.0. On the basis of this analysis, potential exposure from accidental ingestion of surface water contaminants or dermal absorption of contaminants from surface water--either alone or as the combination of both routes of exposure--is not expected to result in any adverse effects. It should be noted that ADD/ADI ratios were calculated for exposure to noncarcinogens and for chronic noncarcinogenic effects of carcinogens.

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Upper-bound, lifetime cancer risks due to exposure to the carcinogens identified in marshland surface water did not exceed 10-9 for either exposure scenario. The total risk associated with accidental ingestion plus dermal -absorption did not exceed 10-9 .

3. Exposure to Volatile Organic Contaminants in the Marshland Area of Winding River Park--Inhalation

Exposure Scenario Exposure to volatile organic chemrcals in the

marshland area of Winding River Park was identified as a potential exposure pathway for the population in the surrounding community. One potential pathway of exposure to surface water contaminants was modeled--inhalation of volatile organic chemicals.

In modeling inhalation of volatile organic contaminants, it was assumed that a child could inspire contaminants for two hours per day and that 100\ of inspired contaminants would be absorbed from the lungs to the bloodstream .

For a more complete description of the exposure scenarios modeling inhalation of volatile contaminants in the marshland area of the Winding River Park, see Appendix E, Scenarios E (for carcinogens) and EE (for noncarcinogens). For numerical estimates of risk derived from the modeled ambient air concentrations under the exposure conditions of these scenarios, see Appendix F, Tables 3 and 4.

Assessment of Risks Air concentrations of organic chemicals were

preliminarily estimated from the detected levels of these contaminants in marshland surface water. None of the chemicals were estimated to be present at levels which,

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under the modeled scenario, resulted in ADD/ADI ratios which exceeded 1.0. On the basis of this analysis, potential exposure due to inhalation of volatile chemicals is not expected to result in any adverse effects. It ·should be noted that ADD/ADI ratios were calculated for exposure to noncarcinogens and for chronic noncarcinogenic effects of carcinogens. Upper-bound, lifetime cancer risks due to inhalation of the carcinogens estimated to be present in marshland air did not exceed 10-7 .

Because inhalation of volatiles represented the route of potentially greatest exposure, ambient air concentrations were measured in the marshland area by Radian during September 1986. Cancer risks associated with long-term exposure to the maximum contaminant concentrations measured do not exceed 10-7 and are comparable to those estimated by ENVIRON using the box model. Non-cancer risks were also found to be of no concern since ADD/ADI ratios did not exceed 1.0 for the volatile chemicals of concern.

Using the calibrated box model, ENVIRON estimated air concentrations in the marshland area assuming that under extreme conditions the surface water temperature could reach 25° c. This hypothetical scenario demonstrated little additional _risk and for the conditions of potential exposure predicted cancer risks which did not exceed 10-7 and ADD/AD I r.atios of less than 1. 0. Clearly, even

under the most extreme conditions no significant adverse health effects would be expected for children playing in the marshland.

4. Total Risk Associated with Marshland Exposure An assessment of total risk for the population that

could come in contact with marshland contaminants is generally based on the sum of potential risks for each medium (soil, water, or air). Summing risks from all

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potential routes in the marshland resulted in total ADD/AD! ratios which did not exceed 1.0, and in total upper-bound, lifetime cancer risks which did not exceed 10-7 . These total risks are presented in Tables 4 and 5, Appendix F.

B. The Toms River Exposure of humans to contaminants in the Toms River is

judged to be associated with recreational activity (e.g., fishing) in the upper portion of the River. ·There are presently no organized or supervised recreational activities for children at this area of the river, but it is not unreasonable to assume that children may play in or near the river. Recreational fishing does take place in the upper section of the river, and it is reasonable to assume that recreational fishing could result in ingestion of fish by the fisherman and also by members of his family, as well as in exposure of the fisherman to contaminants while present at the river.

ENVIRON has considered a number of exposure scenarios and has chosen to model exposure to contaminants in river soil (as a result of unintentional soil ingestion and dermal absorption), exposure to contaminants in river water (also as a result of unintentional water ingestion and dermal absorption), and inhalation of volatile organic chemicals. Because the river could be considered an inviting place for a child to play, potential exposure for a nine-year-old child was modeled. Because recreational fishing takes place at this part of the river, exposure of a fisherman was also modeled. Under these exposure scenarios, it was assumed that children from around the ages of six to twelve (using a nine-year-old child as an average) could play in the river 210 times over a 7-year period (e.g., 2 times a week during the 15 warmer weeks of the year, for the 7 years from ages six to twelve). Children younger than six years of age are unlikely to be found playing away from home unattended. Fishermen were assumed to be present at the river

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an average of 30 times a year for the 52 years of adulthood (ages 18 to 70), e.g., 2 times a week for the 15 warmer weeks of the year. ENVIRON also modeled ingestion of contaminated fish by a family (comprised of an adult male, an adult female, a four-year-old child, a nine-year-old child, and a fifteen-year-old child).

Estimated human intakes from each route were used to derive numerical estimates of risk for each exposure. If more than one route of exposure was identified, then total risk from exposure to the TRP contaminants identified in that medium was determined by summing the risks from each route of exposure (e.g., risk. from accidental ingestion of soil and the risk from dermal absorption from soil).

1. Exposure to Soil Contaminants at the Toms River--Accidental Ingestion and Dermal Absorption

Exposure Scenario Exposure to soil contaminants in the Toms River was

identified as a potential exposure pathway for the population in the surrounding community. Two potential pathways of exposure to soil contaminants were modeled--unintentional ingestion of soil and dermal absorption from soil.

In modeling accidental ingestion of contaminated soil and sediment, it was assumed that a nine-year-old child could potentially ingest 100 mg of soil each time he played near the river, and that 100% of ingested contaminants would be absorbed from the soil by the gastrointestinal tract. It was assumed that an adult fisherman would ingest 10 mg of soil each time he fished, and that 100% of ingested contaminants would be absorbed from the soil by the gastrointestinal tract. In modeling dermal absorption of soil contaminants for both receptors, it was assumed that each could expose half of his total body surface area to the soil and sediment each time he was present at the river.

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Dermal absorption was assumed to be less than 100% because of the barrier provided by the skin. On any given day, dermal absorption from soil was assumed to be 1% of that present in the soil on the skin surface for chemicals with a high K

0w (log K

0w greater than 4), based on a

conservative estimate using dermal absorption data by Poiger and Schlatter (1980). On any given day, dermal absorption for all other chemicals was assumed to be 10%. The dermal absorption coefficients and log K

0ws for all

the chemicals evaluated for the TRP are· in Tables 1 and 6, Appendix F.

F.or a more complete description of the exposure scenarios modeling accidental ingestion of contaminated soil in the Toms River, see Appendix E, Scenarios F (for carcinogens) and FF (for noncarcinogens). For the exposure scenarios that model dermal absorption from contaminated soil in the river, see Appendix E, Scenarios G (for carcinogens) and GG (for noncarcinogens). For numerical estimates of risk derived from the detected soil contaminant concentrations under the exposure conditions of these scenarios, see Appendix F, Tables 8, 9, and 10.

Assessment of Risks Several organic chemicals were identified in sediment

samples from the Toms River. None of these chemicals were present at levels which, under the modeled exposure scenarios, resulted in ADD/ADI ratios which exceeded 1.0. On the basis of this analysis, potential exposure from accidental ingestion of soil contaminants or dermal absorption of contaminants from soil -- either alone or as the combination of both routes of exposure -- is not expected to result in any adverse effects. It should be noted that ADD/ADI ratios were calculated for exposure to noncarcinogens and for chronic noncarcinogenic effects of carcinogens.

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Upper-bound, lifetime cancer risks due to exposure to the carcinogens estimated in river soil did not exceed 10-9 for either exposure scenario. The total risk associated with accidental ingestion plus dermal absorption did not exceed 10-9 .

2. Exposure to Water Contaminants at the Toms River--Accidental Ingestion and Dermal Absorption

Exposure Scenario Exposure to water contaminants in the Toms River was

identified as a potential exposure pathway for the population in the surrounding community. Two potential pathways of exposure to water contaminants were modeled--unintentional ingestion of water and dermal absorption from water.

In modeling accidental ingestion of contaminated water, it was assumed that a nine-year-old child and an adult fisherman could potentially ingest 5 ml of water each time they played or fished in the river area, and that 100\ of ingested contaminants would be absorbed from the water by the gastrointestinal tract. In modeling dermal absorption of water contaminants for both receptors, it was assumed that each could expose half of his total body surface area to the soil and sediment each time he was present at the river.

Dermal absorption of chemicals from water was assumed to\be greater for chemicals with a higher affinity for hydrophobic media than for water (as conservatively indicated by an octanol-water partition coefficient,

Kow' greater than 104 or a log K

0w greater than 4).

This assumption was made because skin exhibits hydrophobic properties and is a less effective barrier to more lipid soluble chemicals. The conservative assumption was made that, on any given day, dermal absorption from water for

chemicals with a log K0w greater than 4 is 50% of that

present in water on the skin surface based on dermal

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absorption data by Poiger and Schlatter (1980), and that dermal absorption for all other chemicals is 10%. The dermal absorption coefficients and log K

0ws for all the

chemicals evaluated for TRP are in Tables 1 and 6, Appendix F.

For a more complete description of the exposure scenarios modeling accidental ingestion of contaminated water in the Toms River, see Appendix E, Scenarios H (for carcinogens) and HH (for noncarcinogens). For the exposure scenarios that model dermal absorption from contaminated water in the river, see Appendix E, Scenarios I (for- carcinogens) and II (for noncarcinogens). For numerical estimates of risk derived from the detected water contaminant concentrations under the exposure conditions of these scenarios, see Appendix F, Tables 8, 9, and 10.

Assessment of Risks Several organic chemicals were identified in ground

water samples associated with the water in the Toms River. None of these chemicals were present at levels which, under the modeled exposure scenarios, resulted in ADD/ADI ratios which exceeded 1.0. On the basis of this analysis, potential exposure from accidental ingestion of river water contaminants or dermal absorption of contaminants from river water--either alone or as the combination of both routes of exposure--is not expected to result in any adverse effects. It should be noted that ADD/ADI ratios were calculated for exposure to noncarcinogens and for chronic noncarcinogenic effects of carcinogens.

Upper-bound, lifetime cancer risks due to exposure to the carcinogens estimated in river water did not exceed lo-10 for either exposure scenario. The total risk

associated with accidental ingestion plus dermal absorption did not exceed 10-10 .

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3. Exposure to Volatile Organic Contaminants at the Toms River--Inhalation

Exposure Scenario Exposure to volatile organic chemicals· at the Toms

River was identified as a potential exposure pathway for the population in the surrounding community. Air concentrations of contaminants at the Toms River were not available but were judged insignificant based on the low concentrations detected in the water.

4. Total Risk Associated with Exposure at the Toms River An assessment of total risk for the population that

could come in contact with Toms River contaminants is generally based on the sum of potential risks for each medium (soil, water, air). Summing risks from all potential routes at the river resulted in ADD/ADI ratios which did not exceed 1.0, and in total upper-bound, lifetime cancer risks which did not exceed 10-9 . These total risks are presented in Tables 9 and 10, Appendix F .

5. Ingestion of Fish from the Toms River

Exposure Scenario Ingestion of fish from the Toms River was identified

as a potential route of exposure for local recreational fishermen and others who might consume the fish. ENVIRON has assessed the risks from eating potentially contaminated fish for an adult male, an adult female, a four-year-old child (average of ages two to six), a nine-year-old child (average of ages six to twelve), and a fifteen-year-old child (average of ages twelve to eighteen). Based on USEPA's estimate of per capita fish consumption, average fish consumption is estimated to be about 6.5 grams of fish per day (USEPA 1980o). It was assumed that each chemical was completely absorbed from the gastrointestinal tract and that all fish consumed carne

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from contaminated sections of the river. Since the Toms River is not appreciably contaminated (see section VI), these assumptions are highly likely to overestimate exposure. Bioconcentration factors (BCF), used to estimate concentrations of contaminants in fish from concentrations in river water, are presented in Table 6, Appendix F.

For a more complete description of this exposure scena+io and calculations used to determine risks from ingesting fish from the Toms River, see'Appendix E, Scenarios K (for carcinogens) and KK (for noncarcinogens). For numerical estimates of risk derived from the detected contaminant concentrations in wells associated with the water in the Toms River under the exposure conditions of these scenarios, see Appendix F, Tables 8, 9, and 10.

Assessment of Risks Several organic chemicals were identified in ground

water discharging to the Toms River; concentrations of these contaminants in fish from the river were estimated by use of bioconcentration_factors. None of the chemicals were present in ground-water samples at levels which, under the modeled exposure scenarios, resulted in ADD/AD! ratios which exceeded 1.0. On the basis of this analysis, potential exposure from ingestion of contaminated fish is not expected to result in any adverse effects. It should be noted that ADD/AD! ratios were calculated for exposure to noncarcinogens and for chronic noncarcinogenic effects of carcinogens. Upper-bound, lifetime cancer risks due to expos~re to the carcinogens estimated in river water did not exceed 10-7 for this exposure scenario.

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6. Total Risk Associated with Exposure at the Toms River and Ingestion of Fish An assessment of total risk for the populations that

could come in contact with Toms River contaminants is generally based on the sum of the potential risks for each medium (soil, water, or fish). Summing these risks resulted in total ADD/AD! ratios which did not exceed.l.O, and in total upper-bound, lifetime cancer risks which did not exceed 10-7 . These total risks are presented in Tables 9 and 10, Appendix F.

7. Environmental Risks Table 5 is a listing of the identified gro~d-water

contaminants (as listed in Table 6, Appendix F) showing the· lowest concentrations at which adverse effects on aquatic life have been reported. Data from chronic aquatic toxicity tests are listed where possible, in the absence of chronic data acute test data are listed. The table also. lists the predicted concentrations in the Toms River at average flow based on the mass loading model generated f~om the ground-water data (Section VI. B.). For each compound, the predicted river concentrations are at least several orders of magnitude lower than the lowest concentrations at which toxic effects have been reported in aquatic organisms. In addition, analyses of sediment samples taken from the river near RI-9 found several chlorinated organic compounds as contaminants (see Table 6, Appendix F). All these sediment concentrations were also far below toxic levels identified for water.

Based on the data available, ENVIRON concludes that contaminants discharging to the Toms River are likely to have no adverse impact on aquatic organisms.

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Aquatic Toxicity Data For Chemicals Evaluated For The Toms River

Lowest Calculated

Reported Toxic Average Flow River

Compound Spedes Test Concentration (ug/1) Concentration (ug/1) References

Bl uegi 11 96 hr Lc50

6 -1 Acetone 8.3 X 10 8.23 )( 10 Verschueren 1983 ' -2 Aniline no data located 4.3 )( 10

Rainbow 96 hr Lc50

3 -1 Benzene trout 5.3 )( 10 1.26 X 10 USEPA 1980a

Carbon disulfide no data located 2.0 X 10-2

4-Chloroanil ine Bluegill 96 hr LC50 2.0 X 103

1.1 X 10-2 Verschueren 1983

~ 4 Chlorobenzene Bl uegi 11 LC50 1.59 )( 10 2.99 USEPA 1980c

3 -1 Chloroform Rainbow trout 27-day LC50 1.24 )( 10 1.55 X 10 USEPA 1980d

2-Chlorophenol Bluegi 11 24-96 hr Tlm 8.0 X 103

5.0 X 10-3 Verschueren 1983

Chlorotoluene Guppy 14 day LC50

5.9 X 103

3.0 X 10-3 Verschueren 1983

(p-chlorotoluene)

1,2-Dichlorobenzene Rainbow trout 103 -1 96 hr Lc

50 1.67 X 2.76 X 10 USEPA 1980e

1,3-Dichlorobenzene Fathead minnow chronic 1. 51 )( 103 9.0 X 10-3

USEPA 1980e

1,4-Dichlorobenzene Fathead minnow chronic 7.63 X 102

2.3 X 10-2 USEPA 1980f

0 1,2-0ichloroethane 81 uegi 11 96 hr Lc50

4.3 X 105 4.0 X 10-3 USEPA 1984a H

al 10

3 10-3 1, 1-Dichloroethylene Fathead minnow chronic (NOEL) 2.8 X 4.0 X US EPA 1980g

s 6 -1 USEPA 1980g s t-1,2-Dichloroethylene 81 uegi 11 96 hr Lc50

1.35 X 10 7.38 X 10 ... ... ~ ID (,.)

--- • • TABLES tCont'dl

Aquatic Toxicity Data For Chemicals Evaluated For The Toms River

lowest Calculated

Reported Toxic Average Flow River

Compound Species Test Concentration (ug/1) Concentration (ug/1) References

1,2-Dichloropropane Fathead minnow chronic 8.1 X 103

1.4 X 10""2 US EPA 1980h

Ethyl benzene Fathead minnow chronic (NOH) 4.4 X 102

1.0 X 10-2 USEPA 1980i

Hexachloroethane no data located 7.0 X 10-3

Methylene chloride Fathead minnow LC50 1.93 X 105 1.87 US EPA 1984b

(dichloromethane)

Naphthalene Fathead minnow chronic 6.20 X 10 2

5.7 X 10 -2 USEPA 1980j

Nitrobenzene Fathead minnow . chronic (NOEL) 3.2 X 10 5

6.0 X 10-3 US EPA 1980k

Phenol Fathead minnow chronic 2.56 X 10 3 2.0 X 10-3

US EPA 19801

1,1,2,2-Tetrachloro- Guppy 7 day LCso 3. 7 X 104 4.7 X 1o-2 Verschueren 1983 ethane

4 -1 Tetrachloroethylene Fathead minnow 96 hr LC

50 1.84 X 10 1.47 X 10 Verschueren 1983

3 -2 Toluene Sheepshead minnow chronic 5.0 X 10 3.3 X 10 USEPA 1980m

1,2,4-Trichlorobenzene Fathead minnow chronic 2.86 X 102

1.29 X 10 -1

USEPA 1980c

1,1,2-Trichloroethane Fathead minnow 96 hr LCSO 8.17 X 104

4.0 X 10-3 USEPA 1981b

n Trichloroethylene Fathead minnow 96 hr LC50 4.07 X 104

13.8 USEPA 1980n ....

104

X 10-1 tD Trichloropropane Guppy 7 day LC50 4.2 X 9.08 Verschueren 1983

103 -2

Q Xylene Bass (p-xylene) 96 hr LC50 2.0 X 1.0 )( 10 Verschueren 1983 Q • ... ~ ID •

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VIII. UNCERTAINTIES AND LIMITATIONS IN THE RISK ASSESSMENT

Data limitations and uncertainties are inherent to the risk assessment process at hazardous waste and other industrial sites. First, it is unlikely, no matter how extensive the environmental sampling and analysis, that the actual levels of contaminants in the various environmental media will be known with absolute certainty for the whole site or surrounding area. Second, a number of critical assumptions are required in developing each of the exposure scenarios and predicting the levels of contaminants to which potential receptors are exposed. Finally, the toxicological and dose-response data that exist on the identified chemicals of concern usually are of varying quality and quantity which creates uncertainties in their interpretation.

In addressing such uncertainties, as a matter of conservative public health policy, USEPA and other regulatory agencies P!efer to err on the side of overestimating risk, in order to protect public health. This is generally accomplished by incorporating conservative assumptions or assumptions which are the upper-bound of reasonably foreseeable exposures into the risk assessment process. In developing exposure scenarios, ENVIRON has incorporated the upper-bound of reasonably foreseeable circumstances to model risks to populations potentially exposed to chemicals originating from the TRP site. The remainder of this section discusses the major data limitations and resultant uncertainties in the risk assessment of the TRP site.

A. Limitations and Uncertainties of Sampling Protocols and Data This report is based on air, soil, sediment, ground-water,

and surface water data specific to the TRP site and surrounding area provided to ENVIRON. The data, however, are limited to those compounds which could be identified and quantified using published EPA procedures. Further quantification and

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identification of other compounds believed to be present should be incorporated in this risk assessment, when available. Moreover, the report is accurate and complete, only to the extent that information provided by AWARE, SR Analytical, JTC Environmental Consultants, Radian Corporation and made available by USEPA was itself accurate and complete.

The soil (sediment) sampling data from the marshland area of Winding River Park are limited to the samples collected by JTC Environmental Consultants on March 4, 1986. Surface water data were collected by JTC during the March ·sampling event and by Radian Corporation on September 11, 1986. In addition, Radian collected ambient air monitoring data in the marshland. on September 11 and 12, 1986 on volatile organic contaminant concentrations.

The six sediment samples ·and ~hree water samples obtained by JTC during March 1986 provided the basis for a preliminary health risk assessment associated with potential exposures in the marshland area. During this preliminary assessment, ENVIRON used the concentrations of contaminants detected in marshland surface waters to estimate air concentrations of volatile organic pollutants. As ENVIRON determined through this analysis that the volatile organic contaminants benzene, chloroform, chlorobenzene, and trichlorobenzene were the major contaminants of concern in the marsh area, analysis of all of the surface water and air samples collected by Radian in September, 1986 were limited to VOC determinations. Furthermore, the assessment of risks via inhalation exposure in the marshlands focuses on the major VOCs of concern listed above.

The risk assessment of potential exposures to TRP contaminants in water at the Toms River is based on analyses of ground-water samples from twenty-four monitoring wells in close proximity to the river and sediment sampling data collected by JTC Environmental Consultants from the RI-9 area. As discussed below, no information was available on air concentrations of potential river contaminants .

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B. General Limitations in Toxicity Data· In the great majority of risk assessments, the risk

assessor rarely has available complete scientific information to provide a thorough understanding of the toxic properties of chemicals to which humans are potentially exposed. For most chemicals, including the chemicals addressed in this risk assessment, adequate human data for assessing risk are usually not available, and the likelihood of adverse effects in humans must be predicted from data in experimental animals. It should be emphasized that only a small number of chemicals have actually been identified as human carcinogens and many animal carcinogens· in fact have not been identified as human carcinogens. For animal carcinogens which are not human carcinogens, the actual ADI would certainly be higher than the dose calculated to produce a 10-6 cancer risk.

For the chemicals addressed in this assessment, estimates of likely human risk were often necessarily based on experimental animal studies involving a different route of exposure than that by which humans are exposed. Moreover, adverse effects from low-dose, chronic exposure in humans were often predicted from animal stuqies involving administration of much higher doses over a relatively short period of exposure. In using such data to predict human risk of chronic exposure to noncarcinogens, some attempt was made to adjust for interspecies comparison and duration of exposure differences by the application of "safety" or "uncertainty" factors. These factors were generally of a magnitude such that it is more likely that human risk was overestimated than underestimated.

c. Effects from Exposure to Mixtures of Chemicals All of the assessments presented in the previous section

consider the risk from exposure to an individual chemical. As with most exposures to_chemicals, potential exposure to compounds originating from the TRP site involves exposure to many chemicals at the same time.

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Concurrent exposure to two or more chemicals can produce toxicological effects that are independent, synergistic, antagonistic, or additive. Although there is much interest in the toxicological effects of mixtures, the available information on such toxicological effects is very limited. In the absence of data to the contrary, the USEPA (1986) has suggested that risks from exposure to mixtures of chemicals be estimated as though their effects were additive. The fact that the risk assessment process for each chemical tends to overestimate the risks for any one chemical •is likely to compensate for any additive (or synergistic) effects among chemical mixtures.

D. General Limitations in Exposure Assessment In most any risk assessment, a large number of assumptions

must be made in attempting to assess potential human exposure. In the present case, it was necessary to develop assumptions about general characteristics and potential patterns of human exposure of the population in the vicinity of the TRP site. The exposure scenarios were largely developed independent of current or future off-site characteristics (i.e., the marshland is relatively accessible) or or any future changes in usage of the areas ENVIRON has considered. Moreover, the hypothetical scenarios assume the current level of off-site contamination will continue indefinitely. Furthermore, for the scenarios involving a child playing in the river or marshland, it was necessary to make assumptions about the number of times per week this could occur, the amount of soil and water to which the child's body could be exposed, the amount of soil and water a child could ingest from such an exposure, and the amount of each chemical in soil and water that could be absorbed by each route of exposure. Limitations in the available soil, water, and air monitoring data (as described above) added further uncertainty to resultant exposure estimates. Nevertheless, in

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developing each exposure scenario, ENVIRON attempted to be conservative, such that risk was more likely overestimated than underestimated .

E. Pathways of Potential Exposure In this assessment the potential doses that could be

received from various media within individual exposure scenarios were added. For example, it was assumed that a child playing at the marshland could ingest and be dermally exposed to contaminated water, could ingest and be dermally exposed to contaminated sediment, and could inhale volatile organic chemicals .. Doses from these exposure pathways were summed to estimate potential total risk. The potential doses an individual could receive as a result of experiencing a combination of exposure scenarios (e.g.; routinely playing at both the marshland and at the Toms River) were not determined. This is because it is highly unlikely that any given individual would concurrently experience more than one set of exposures (as defined in the exposure scenarios). However, "it was considered reasonable to assume that an individual could be · exposed to contaminants at the Toms River and consume contaminated fish from the river. Thus, while one could speculate that this practice may have underestimated risk, given the generally conservative assumptions applied in the individual scenarios and the improbable concurrent exposure to any individual, such underestimation is very unlikely.

An attempt was made to model all pathways considered to be of concern to public health. Despite data limitations, all identified pathways were modeled, except inhalation_of volatile

·chemicals at the Toms River. Air concentrations of contaminants at the Toms River were not available but were judged insignificant based on the low concentrations detected in the river water.

As discussed in detail earlier, CIBA-GEIGY has identified 14 irrigations wells in the northern section of Oak Ridge Subdivision and samples were taken from 11 wells for analysis .

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According to information provided to ENVIRON, no sampled irrigation wells which exceed USEPA existing or proposed drinking water standards for organic chemicals are being used for body-contact purposes (drinking, cooking, bathing, swimming pools., etc.). Thus, ENVIRON did not conduct a risk assessment associated with the use of irrigation wells.

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IX. SUMMARY AND CONCLUSIONS

The risk assessment presented in this report was undertaken to evaluate the potential risk to public health and the environment as a result of reasonably foreseeable exposures to potential contaminants in soil and in ground water migrating from the Toms River Plant. This assessment is based upon monitoring data and general information gathered by ENVIRON Corporation, AWARE Incorporated, SR Analytical, JTC Environmental Consultants, Radian Corporation and the NUS Corporation.

Toxicity data on ground-water contaminants were reviewed, and unit cancer risks (UCRs) for carcinogens and acceptable daily intakes (ADis) for noncarcinogenic effects were based on this data. ENVIRON generally used values for UCRs and ADis developed by USEPA; in cases where a UCR or ADI was not available, ENVIRON derived these values, using methodology consistent with that applied by USEPA. ENVIRON modeled those potential exposure pathways considered to be the most significant for specific populations (e.g., exposures to soil, water, and air for a child playing in the marshland area of Winding River Park). It should be noted that the exposure scenarios presented in this report were designed to provide an upper-bound estimate of reasonably foreseeable exposure to assess the potential public health risks associated with exposure to contaminants from the TRP, even assuming no remedial measures are implemented.

Ground-water sampling in August, September and October of 1985, as part of the on-going hydrogeological investigation, identified a plume of contamination migrating from the TRP toward the Toms River. This plume of contamination appears to discharge, in part, as ground-water "seeps" in the marshland area located on the western bank of the river, adjacent to the northern section of the Oak Ridge Subdivision. Public and private well systems on adjacent properties appear to be unaffected by the discharge from the Toms River site except for private wells in the path eastward to the Toms River through

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the northern portion of the Oak Ridge Subdivision. While all the Oak Ridge Subdivision residences are supplied with drinking water from the Toms River Water Company, some have private wells that could be used for irrigation or other such activities. In August of 1986, CIBA-GEIGY conducted a door-to-door survey in an area which included the area of known ground-water contamination plus a four block buffer zone to the south. Fourteen irrigation wells were located in this area; no domestic wells were found. Samples were taken from 11 wells for analysis. Three wells were not sampled ~y CIBA-GEIGY, however, as two wells were not operational and one homeowner located in the southern most portion of the buffer zone refused to have his well sampled. CIBA-GEIGY offered to seal the wells or to periodically test those wells which suggested evidence of contamination.

Of the irrigation wells sampled by CIBA-GEIGY, only three wells exceeded standards or proposed standards established by the USEPA under the Safe Drinking Water Act. Since that time one homeowner accepted CIBA-GEIGY's offer and his irrigation well was sealed. Although arrangements have not yet been made for closure of the other two irrigation wells, one well has reportedly not been used since 1985 and the other home uses its irrigation well only for lawn watering via an in-ground sprinkler system.

Therefore, since no sampled irrigation wells which exceed USEPA existing or proposed drinking water standards for organic chemicals are being used for body-contact domestic purposes (drinking, cooking, bathing, swimming pools, etc.), ENVIRON did

not conduct a risk assessment associated with the use of. irrigation wells. CIBA-GEIGY has informed ENVIRON of planned actions to identify and seek closure of potentially affected wells. ENVIRON believes these actions will. effectively preclude future exposure to potentially contaminated ground water from this source.

Sampling of sediment and surface water was conducted in the marshland area adjacent to the Oak Ridge Subdivision during

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March, 1986. This marshland area is close to and easily accessible from the Oak Ridge Subdivision and is adjacent to a heavily used recreational area of Winding River Park .

The marshland area sampled is located between the contour lines'of highest total volatile priority pollutants (as prepared by AWARE). Six sediment samples and three water samples revealed the presence of volatile organic contaminants and provided the basis for the health risk assessment associated with potential exposures in the marshland area. ENVIRON also used the concentrations of contaminants detected in marshland surface waters to estimate air concentrations of volatile organic pollutants. To validate these estimates, air concentrations were measured by Radian Corporation during a September, 1986 field sampling event.

A number of exposure pathways were evaluated by ENVIRON to assess potential risks associated with exposures in the marshland area of Winding River Park. Exposure scenarios considered are:

• ingestion of and dermal contact with contaminanted soil;

• ingestion and dermal contact with contaminated water; and

• inhalation of volatile organic chemicals.

For carcinogenic effects, the estimated lifetime cancer risks ranged from 10-7 (one case in ten million exposed) to 10-8

(one case in one hundred million exposed). Noncarcinogenic effects are not expected to occur since the predicted average daily dose for the contaminants identified was found to be less than the acceptable daily intake.

Extensive hydrogeological studies have identified a plume of contaminants which discharges to the Toms River. ENVIRON addressed potential public health risks associated with recreational use of the river. Contaminant concentrations in ground-water wells nearest to the Toms River were used to estimate the mass loading of chemicals to the river. ENVIRON

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estimates obtained for carcinogenic effects are in the range of 10-7 (one case in ten million exposed) to 10-12 (one case in one trillion exposed) for the exposure scenarios examined . These risk levels are well below the risk levels generally found to be significant by public health regulatory agencies.

Noncarcinogenic health effects are not expected to occur under any of the assumed conditions of exposure since the predicted average daily dose for the identified contaminants was found to be less than the acceptable daily intake in all instances. For noncarcinogenic effects, the-average daily dose was compared to the acceptable daily intake (ADD/ADI ratio); ADD/ADI ratios which do not exceed 1.0 generally do not indicate significant risk to public health.

These findings are limited to volatile organics, acid extractable, and base/neutral extractable compounds identified and quantified in ground-water, surface water, or sediment samples, and the volatile organic chemicals of concern measured in air samples taken from the marshland area. This risk assessment will be revised in light of any additional analytical data or hydrogeological findings that have a material bearing on potential risk.

In addition, ENVIRON compared predicted river concentrations of contaminants with the lowest concentrations at which adverse effects on aquatic organisms have been reported. For each compound, the predicted river concentrations are at least several orders of magnitude lower than the lowest concentrations at which toxic effects have been reported in aquatic organisms. Further, analyses of river sediment indicate contaminant levels are far below toxic levels identified for water. Based on the data available, ENVIRON concludes that contaminants discharging to the Toms River are not likely to have any adverse impact on the aquatic environment.

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REFERENCES

AWARE Incorporated. 1986. Hydrogeologic and Related Environmental Investigation Report of The CIBA-GEIGY Corporation, Toms River Plant, Toms River, New Jersey, Volumes I-VI.

Baynes, C.J. 1986. Memorandum from Colin Baynes to ENVIRON. Ref: Flow under Forest Canopy.

,, Davenport, A.G. 1965. The Relationship of Wind Structure to Wind

Loading. In: Wind Effects on Buildings and Structures. National Physical Lab., Symposium 16, HMSO, London.

ENVIRON Corporation. 1986. A NUmerical Three-Dimensional Ground­Water Flow Model of the Toms River Plant Area.

Horst, T.W.- 1979. Lagrangian Similarity Modeling of Vertical Diffusion from a Ground Level Source. International Applied Meteorology, 18:733-740.

International Commission on Radiological Protection (ICRP). 1984. Report of the Task Group on Reference Man. ICRP Publication No. 23. New York: Pergamon Press.

Kimbrough, .·R.D., H. Falk, P. Stehr, and G. Fries. 1984. Health implications of 2,~,7,8-tetrachlorodibenzodioxin (TCDD) contamination of residential soil. J. Toxicol. Environ. Health 14:47-93 .

Lepow, M.L., L. Bruckman, M. Gillett, S. Markowitz, R. Robino, and J. Kapish. 1975. Investigation into sources of lead in the environment of urban children. Environ. Res. 10:415-426.

National Research Council (NRC). 1983. Risk Assessment in the Federal Government: Managing the Process. Washington, D.C.: National Academy Press.

NUS Corporation. 1986. Remedial Investigation Ciba-Geigy Site Toms River, Dover Twp. Ocean County, NJ. Revision 2. NUS FIT project No. 0488.01. R-584-06-86-06. September 1986.

Pasquill, I. 1975. The Dispersion of Material in the Atmospheric Boundary Layer - the Basis for Generalization. In: Lectures on Air Pollution and Environmental Impact Analyses. American Meteorological Society, Boston, Massachusetts.

Poiger, H., and c. Schlatter. 1980. Influence of solvents and adsorbants on dermal and intestinal absorption of TCDD. Fd. Cosmet. Toxicol. 18:477-481.

Radian Corporation. 1986. Ciba-Geigy Air Toxics Monitoring Program. Draft Report. Austin, Texas .

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Shen, T.T. 1982. A Simplified Method for Estimation of Hazardous Emissions from Waste Lagoons. Presentation at the 75th Annual Meeting of the Air Pollution Control Association .

Turner, B. 1970. Workbook of Atmospheric Dispersion Estimates. USEPA, Research Triangle Park, NC.

u.s. Environmental Protection Agency (USEPA). 1980a. Ambient Water Quality Criteria for Benzene. Office of Water Regulations and Standards, Criteria and Standards Division, Washington D.C. EPA 440/5-80-018.

u.s. Environmental Protection Agency (USEPA). 1980b. Ambient Water Quality Criteria for Chloroalkyl Ethers. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-030.

U.S. Environmental Protection Agency (USEPA). 1980c. Ambient Water Quality Criteria for Chlorinated Benzenes. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-028.

u.s. Environmental Protection Agency (USEPA). 1980d. Water Quality Criteria for Chloroform. Office of Regulations and Standards, Criteria and Standards Washington, D.C. EPA 440/5-80-057.

Ambient Water Division,

u.s. Environmental Protection Agency (USEPA). 1980e. Ambient Water Quality Criteria for Dichlorobenzenes. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-039.

u.s. Environmental Protection Agency (USEPA). 1980f. Ambient Water Quality Criteria for Chlorinated Ethanes. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-029.

u.s.

u.s.

u.s.

Environmental Protection Agency (USEPA). 1980g. Ambient Water Quality Criteria for Dichloroethylenes. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-041.

Environmental Protection Agency (USEPA). 1980h. Water Quality Criteria for Dichloropropane and Dichloropropene. Office of Water Regulations and Criteria and Standards Division, Washington, D.C. 440/5-80-043.

Environmental Protection Agency (USEPA). 1980i. Water Quality Criteria for Ethyl Benzene. Office Regulations and Standards, Criteria and Standards Washington, D.C. EPA 440/5-80-048.

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Standards, EPA

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u.s. Environmental Protection Agency (USEPA). 1980j. Ambient Water Quality Criteria for Naphthalene. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-031 .

u.s. Environmental Protection Agency (USEPA). 1980k. Ambient Water Quality Criteria for Nitrobenzene. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-061.

U.S. Environmental Protection Agency (USEPA). 19801. Ambient Water Quality Criteria for Phenol. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-066.

u.s. Environmental Protection Agency (USEPA). 1980m. Ambient Water Quality Criteria for Toluene. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-041.

u.s. Environmental Protection Agency (USEPA). 1980n. Ambient Water Quality Criteria for Trichloroethylenes. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. EPA 440/5-80-077.

u.s. Environmental Protection Agency (USEPA). 1980o. Guidelines and methodology used in .the preparation of health assessment chapte·rs of the consent decree water quality criteria. Fed. Reg. 45:79347-79357 .

U.S. Environmental Protection Agency (USEPA). 1981a. An Exposure and Risk Assessment for 1,1,2,2-Tetrachloroethane. Final Draft Report. Office of Water Regulations and Standards. Washington, D.C.

u.s. Environmental Protection Agency (USEPA). 1981b. An Exposure· and Risk Assessment for Trichloroethanes. Final Draft Report. Office of Water Regulations and Standards. Washington, D.C.

u.s. Environmental Protection Agency (USEPA). 1984a. Health Assessment Document for 1,2-Dichloroethane (Ethylene Dichloride). Review Draft. Office of Health and Environmental Assessment. Washington, D.C. EPA-600/8-84-006A.

u.s. Environmental Protection Agency (USEPA). 1984b. Health Assessment Document for Dichloromethane (Methylene Chloride). Final Report. Office of Health and Environmental Assessment .. Washington, D.C. EPA/600/8-82/004F.

u.s. Environmental Protection Agency (USEPA). 1985a. Health assessment document for chloroform. EPA/600/8-84/004F .

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u.s. Environmental Protection Agency (USEPA). 1985b. Superfund public health evaluation manual. Draft. Prepared by ICF Incorporated. EPA Contract No. 68-01-7090, Task Number 07.

u.s. Environmental Protection Agency (USEPA). 1986a. Guidelines for the health risk assessment of chemical mixtures. Fed. Reg. 51:34013-34025.

u.s. Environmental Protection Agency (USEPA). 1986b. Verified reference doses (RFDs) of the u.s. EPA. Prepared by: The ADI Work Group of the Risk Assessment Forum. EPA ECAO-CIN-475.

United States Geological Survey (USGS). 1982. Low-flow Characteristics and Flow Duration of New Jersey Streams. u.s. Geological Survey Open-File Report 81-1110.

Verschueren·, K. 1983. Handbook of Environmental Data on Organic Chemicals. Second edition. New York: Van Nostrand Reinhold Company .

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