The Revere Chemical National Priorities List (NPL) site is located on the southeast side of Pennsylvania State Route 611, approximately three quarters of a mile south of the town of Revere in Nockamixon Township, Bucks County, Pennsylvania. The site has an area of 113.5 acres and the portion used for process operations is approximately 25 acres. This area of the site has an 8-foot high security fence and is not accessible to the public. Operations at the Revere Chemical site were initiated in 1963 and reportedly involved the recycling of spent chromic acid solutions, the recovery of copper from electric plating solution, and the reclamation of metals from printed circuit boards. In 1984, a fire at the site offices destroyed most company documents. Consequently, detailed descriptions of site operations are unavailable.

The process area soils are contaminated with volatile organic compounds and metals. Soil contamination decreases markedly with distance from the process area. Trichloroethene (TCE) and 1,2,4-trichlorobenzene (TCB) were detected in on-site monitoring well MW-4 at concentrations of 110 micrograms per liter (µg/L) and 41 µg/L, respectively. However, neither TCE nor TCB were detected in the groundwater samples collected from monitoring well MW-11, which is located approximately 150 feet away from MW-4 in a downgradient direction. No VOCs were detected in the off-site residential groundwater samples. None of the Target Analyte List metals or hexavalent chromium concentrations detected exceeded Federal Primary Drinking Water Standards in the filtered or unfiltered groundwater samples collected from residential wells. There were no community health concerns or completed exposure pathways that indicated that a review of health outcome data was necessary.

However, the Revere Chemical site currently represents an indeterminate public health hazard since groundwater flow direction has not been fully characterized and not all residential wells near the site have been sampled. The Phase 2A Groundwater Investigation now under review will eliminate these data gaps.

Lead, unrelated to the site, was found in one residential well upgradient of the site above the U.S. Environmental Protection Agency proposed guideline of 15 µg/L at the tap.

The data and information developed in the Revere Chemical Public Health Assessment have been evaluated for appropriate follow-up health actions. The Agency for Toxic Substances and Disease Registry (ATSDR) Health Activities Recommendation Panel determined that no follow-up public health actions are necessary. ATSDR will reevaluate this site and conduct appropriate public health actions, if new data become available that indicate a need to do so.

The Pennsylvania Department of Health will continue to review off-site residential well sampling data to determine if any site-related contaminants are migrating.

BACKGROUND

A. Site Description and History

The Revere Chemical National Priorities List (NPL) site is 113.5 acres located on the southeast side of Pennsylvania State Route 611, approximately three quarters of a mile south of the town of Revere in Nockamixon Township, Bucks County, Pennsylvania (Figure 1, Appendix A). It includes two unnamed tributaries of Rapp Creek, and is bounded to the south, east, and west by farmland (Figure 2). Route 611 borders the site on the northwest, and Cotner Trailer, a commercial operation that manufacturers horse trailers, borders the site to the north (1).

A review of available information indicates that operations at the Revere Chemical site were initiated as early as 1963. Facility operations reportedly involved the recycling of spent chromic acid solutions, the recovery of copper from electric plating solutions, and the reclamation of metals from printed circuit boards. The recovered copper was subsequently used to manufacturer copper-based chemical compounds. Detailed records regarding the types and quantities of sludges and plating materials stored on the site during its years of operation are not available (2). However, samples of materials contained in the on-site process basins and lagoons were collected by the Pennsylvania Department of Health (PADOH) in March 1970. On the basis of these data, it is believed that facility processes used chromic acid, copper sulphate, ammonia, ferric chloride, nickel and sulfuric acid solutions (1).

The major areas of facility operations were the process buildings, a series of bermed earthen process and storage lagoons, and the spray fields (Figure 3). The area of the site formerly used for process operations is believed to be approximately 25 acres (1).

In 1968, the Bucks County Department of Health determined that the facility had not submitted the required Pollution Incident Prevention Plan. Later inspections revealed that material was discharging from the process and storage lagoons and was migrating into the unnamed tributaries of Rapp Creek. In December 1969, the site was abandoned by the operators.

During 1970 and 1971, PADOH, the predecessor of the Pennsylvania Department of Environmental Resources (PADER), performed a remedial action at the site, removing an estimated 3.5 million gallons of waste sludges and liquids. Pumpable sludges were removed and disposed of at sea. The remaining sludges were stabilized with lime, sodium sulfide, and sodium sulfite, mixed with native soils, and buried on site in process lagoons and storage lagoons. During this action, drums were reported to have been crushed and buried on site by the PADOH (1).

From March 29 through April 16, 1984, the United States Environmental Protection Agency (USEPA) performed additional remedial work at the site. The USEPA removed 22 drums containing chromic acid and etching wastes, and 30 cubic yards of chemical solids from surface soils and the former on-site laboratory (1).

In 1984, the fire at the site offices destroyed most company documents. Consequently, detailed descriptions of site operations are unavailable (1).

In 1985, NUS Corporation, representing the USEPA, collected 11 soil and 11 aqueous samples from on-site and off-site locations to evaluate the nature and extent of soil and groundwater contamination. In addition, a magnetometer survey was performed in the process area to determine the presence and location of buried metal objects at the site (1).

The Revere Chemical site was proposed for the National Priorities List (NPL) on September 1, 1985 and was finalized on the NPL on July 1, 1987. The Agency for Toxic Substances and Disease Registry (ATSDR) prepared a Preliminary Health Assessment for the site in 1988.

B. Site Visit

Mr. Thomas Hartman and Mr. Robert M. Stroman, with PADOH, Ms. Felicia F. Dailey, ATSDR Regional Representative, and representatives from the Bucks County Health Department, de Maximis, Inc., and Dames & Moore visited the site on November 18, 1991.

Approximately 25 acres of the site were observed to be secured with a chain-linked fence. This 25-acre portion of the site where manufacturing activities occurred, the process area, has been extensively disturbed. No process lagoons or storage lagoons remain. Some scattered trash was noted around the site. Present ground cover in the process area consists of bedrock fragments and is for the most part devoid of vegetation. Yellowish-stained soil provided visual evidence of on-site contamination. The east and west spray fields were also observed. There were no leachate seeps noticed along the banks of the tributaries. The tributaries were nearly dry and a later view of Rapp Creek indicated it was extremely low.

Three major structures were observed on the site. An arsoned office/house, a process building, and a single-story building were all located near the main entrance to the site. Dames & Moore had a work-site trailer near the main gate and Cotner Trailer was just to the north outside the site boundary. The nearest home is less than 0.25 miles from the site.

On December 10, 1993, PADOH determined that some changes have been made at the site. The primary change is that site erosion controls have been installed around the site's perimeter. The erosion control measures consist of silt fencing and stone berms. Trash that was scattered around the site has now been collected into one pile.

C. Demographics, Land Use, and Natural Resource Use

Demographics

The Revere Chemical site is located in Nockamixon Township, Bucks County. The 1990 Census population for Nockamixon Township was 3,329, an increase of 19.4 percent from the 1980 Census population of 2,787 (3). Whites accounted for 98.7 percent of the 1990 population. Nockamixon Township had only 9.5 percent of its population 65 years of age or older compared to 15.4 percent in Pennsylvania in 1990. Bucks County has only 10.9 percent of its population 65 years and older. This is the lowest percent of any of the 67 counties in Pennsylvania with the exception of Centre County which contains the main campus of Penn State University. Bucks County is also a wealthy county with the median home value $140,000 and a median rent of $524 a month compared to $69,700 and $322 respectively for Pennsylvania in 1990 (3). Nockamixon Township had a median housing value of $148,100 and a median monthly rental value of $452 (3).

The area around the site is rural with about 520 people residing within 1 mile of the site. There are approximately 650 private wells within 3 miles of the site, the nearest one being 1,000 feet away (4). There is no public water supply serving this area.

Nockamixon Township is part of the New Hope - Solebury School District. There is an elementary school, a middle school and a high school in Nockamixon Township. These three schools are part of one geographic area over 2 miles northwest of the site. The schools and their 1990-91 enrollments are as follows (5, 6):

There are no hospitals or nursing homes within the immediate vicinity of the site. The nearest hospital and nursing home is located approximately 10 miles southwest of the site in Quakertown Borough (7, 8).

Land Use

The Revere Chemical site is located in a rural area of Bucks County. Revere, an unincorporated place of approximately 200 persons (9), has three small companies listed in the 1990 Industrial Directory of Pennsylvania. These three companies employed a total of 42 persons and Cotner Manufacturing is one of these and borders the site to the north. The area surrounding the site includes recreational streams, forests, fields and state game lands. Nockamixon State Park extends 1-3 miles southwest of the site which contains Lake Nockamixon with an elevation of 396 feet above mean sea level. Approximately 0.5 miles north of the lake is Haycock Mountain with an elevation of 900 feet above mean sea level. The site is situated in the portion of the Piedmont Physiographic province designated as the Piedmont Upland, which is characterized by gently rolling hills and sloping topography (1).

Natural Resource Use

The area surrounding the site is underlain by various members of the Triassic-age Newark Group. The geologic unit in the site vicinity is the Lockatong formation. The lithology of the Lockatong formation is fairly homogenous. The Lockatong and Brunswick formations interbed in the site vicinity. The Lockatong and Brunswick formations are each typically extensively fractured. The Lockatong formation is utilized as an aquifer for residential and commercial purposes throughout Bucks County, including the site vicinity (1).

The residents surrounding the site all depend on private wells as their source of potable water. A survey was conducted of residential well users.

Seventy-nine (79) residential well survey forms were distributed door-to-door to residents within an one-half mile radius of the site during the Phase 1 RI. A total of 38 forms were completed and returned (48.1%). A follow-up survey of the residents that did not respond to the Phase 1 survey was conducted during the Phase 2 investigation. This follow-up survey was accomplished by mailing the Phase 1 questionnaire to the residences. A door-to-door survey of those residents who did not respond to the mailed questionnaire was conducted on October 3, 1991. The objectives of the residential well survey were to: (1) establish an inventory of existing wells in the vicinity of the site, and (2) identify potential receptors of groundwater contamination that may migrate off-site (1).

Thirty-seven (37) residential well surveys were mailed during the Phase 2 RI. The mailing addresses for four residences could not be established, so they were not sent questionnaires during the Phase 2 investigation. A total of six surveys were completed and returned. The door-to-door survey of the remaining 31 residences resulted in the completion of an additional 11 investigations (55 of 79 or 69.6%). Figure 6 indicates the approximate location of the 75 residences in the vicinity of the site (1).

Reported residential well depths range from 60 feet to greater than 600 feet, with an approximate average of 316 feet. Reported well yields range from 5 to 90 gpm, with an average yield of approximately 17 gpm. The majority of the residents indicated hardness as a water quality problem, and several indicated that they use water softeners to address the problem. In addition, several residents cited high iron content as a water quality problem. These data agree with well yield data reported by Greenman (1955) for 43 wells that tap the Lockatong formation, which ranged from 2 gpm to 25 gpm, with an average yield of 10 gpm (1).

A topographical survey was conducted during the Phase I investigation of the site. Elevations on the site range from 390 feet above Mean Sea Level (MSL) in the southeast corner of the site to 514 feet above MSL in two areas along the northern site boundary. The site topography is characterized by two stream channels that join on-site. One stream (east tributary) transects the site from north to south and the other (west tributary) transects the site from west to east. The east tributary flows onto the site at the northern corner of the property and then flows across the site to a point approximately 150 feet from the southeastern site boundary, where it forms a confluence with the west tributary. The west tributary enters at the northwest corner of the site where it flows beneath Easton Road (Pennsylvania State Route 611). This stream flows across the site toward the southeast site boundary and forms a confluence with Rapp Creek approximately 400 feet southeast of the site. Rapp Creek flows into Tinicum Creek which flows into the Delaware River approximately 7 miles from the site. Surface water drainage on the site generally flows toward the south (1).

D. Health Outcome Data

Health outcome data bases were not reviewed for the Revere Chemical site for reasons discussed in the Health Outcome Data Evaluation.

COMMUNITY HEALTH CONCERNS

Concerns in the community have diminished since the mid 1980's because much remediation has been done on-site that is obvious to the surrounding residents. Several residents expressed concern that their wells were not tested for site-related contaminants during the RI/FS. Several additional wells have been tested very recently based on citizens' requests. The results of these tests are not included in the public health assessment; however, it has been reported that the wells were free of contamination or had contaminants at very low levels that would not be expected to cause adverse health effects (10). The major question that is raised by the residents is "What are our health risks from drinking from a private well in close proximity to the site"? This question will be addressed in the Community Health Concerns Evaluation section.
 

The tables in this section list the contaminants of concern. This public health assessment evaluates these contaminants in subsequent sections and determines whether exposure to them has public health significance. PADOH selected these contaminants based upon the following factors: on and off-site concentrations; field and laboratory data quality and sample design; comparison of site-related concentrations with background concentrations; and comparison of site-related concentrations with health assessment comparison values for carcinogenic and noncarcinogenic endpoints. Comparison values for health assessments are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines.

In the data tables which follow under the on-site contamination and off-site contamination subsections, the listed contaminant does not mean that it will cause adverse health effects from exposure. Instead, the list indicates which contaminants will be evaluated further in the public health assessment. When selected as a contaminant of concern in one medium, that contaminant will be reported in all media.

The data tables include the following acronyms:

The USEPA Toxic Chemical Release Inventory data base was accessed by the PADOH through the National Library of Medicine's Toxicology Data Network and searched for estimated annual release of toxic chemicals to the environment, from industries within a 2-mile radius of the Revere Chemical site, to identify possible facilities that could contribute to air or groundwater contamination near the site. No significant releases which would affect the air or groundwater quality near the site were reported in the 1987, 1988 and 1989 data bases.

A. On-Site Contamination

Groundwater - Monitoring Wells

The Phase I groundwater investigation included the installation and sampling of five groundwater monitoring wells, designated MW-1 through MW-5. The Phase IA groundwater investigation consisted of installing and sampling one monitoring well (MW-6). Monitoring well MW-6 was an overburden well that was decommissioned after review of the analytical results indicated the absence of any compounds of concern (1). Six monitoring wells (MW-7 through MW-12) were installed in the process area for the Phase II monitoring wells by Eichelberger Drilling Company of Mechanicsburg, Pennsylvania, from March 25, 1991 through April 5, 1991. These wells were initially drilled to a minimum depth of 100 feet in accordance with the Phase II Work Plan. The wells were then advanced in 25-foot increments until the first water-bearing zone was encountered, at which time drilling was terminated. Appendix B provides monitoring well installation and modification data.

Dames & Moore collected one round of groundwater samples from the Phase I and Phase II monitoring wells on June 12 and 13, 1991. The presence of bentonite in MW-1 prevented the collection of groundwater samples from this well. The groundwater samples collected were analyzed by the Environmental Testing and Certification (ETC) Corporation of Edison, New Jersey. This analysis included: Target Compound List (TCL), volatile organic compounds (VOCs), polychlorinated biphenyls (PCBs), Target Analyte List (TAL) metals, and hexavalent chromium. Figure 4 indicates the well locations and Table 1 indicates the concentrations of contaminants of concern.

Table 1. Maximum Contaminant Concentrations in On-Site Monitoring Wells (1)

^a Unfiltered
^b Child
* In addition to total chromium, tests were conducted for hexavalent chromium in some samples. However, the data have been considered invalid. Future groundwater samples for metals will be analyzed for hexavalent chromium by both the atomic absorption method (USEPA Method No. 218.4) and the colorimetric method (SW 846-7197) (1).

Soil - Phase I

The objectives of the Phase I soil sampling were to: 1) determine the composition, stratification and thickness of on-site soils and 2) evaluate the presence or absence and vertical distribution of potential contaminants in on-site soils. Soil samples were collected from four areas of the site: background soil samples, east spray field, south spray field and the process area. All soil samples and background soil samples were analyzed by ETC for the following parameters (2):

Dames & Moore collected all the samples. The background samples were collected on November 11, 1989. Other samples were collected between October 5-20, 1989. A discussion of the sampling from the other four areas of the site follows.

No interval B sample was collected from location S18, because bedrock was encountered at 1.6 feet. For samples S50 through S56, the interval B sample was collected from 1 to 2 foot BGS.

For samples S50 through S56, six soil samples were collected from interval C, which was the 1-foot interval above bedrock. Bedrock was encountered at 2.4 feet at location S50; thus, the interval B sample was collected from 1.4 to 2.4 foot BGS, and no interval C sample was collected.

The soil samples were collected from 56 trenches excavated with an extendahoe (a backhoe with extended reach). Soil samples collected from the trenches were intentionally biased toward locations that exhibited the most, of any, visual and textural signs of potential contamination (2). The objective of this biased sampling approach was to evaluate the need for further study in each localized area of potential concern. The results of this approach were not intended to be representative of conditions across the whole site; however, they did provide information necessary for Phase II soil sampling.

Contamination to soil was most intensive in the process area. VOC contamination in the soil was nearly confined to the process area. Acid extractable compounds (AEs) and pesticides were so limited in Phase I sampling that they were deleted in the Phase II sampling plan. Tables 2a and 2b indicate maximum concentrations of contaminants of concern in Phase I and Figure 5 indicates the sample locations.

Table 2a. Maximum Contamination Concentration in Selected Areas in Phase I
(Interval A) Soil Sampling (2)

Table 2b. Maximum Contamination Concentration in Selected Areas in Phase I
(Interval B) Soil Sampling (2)

Soil - Phase II

The Phase II soil investigation involved the collection and laboratory analysis of soil samples for metals in the entire process area. Selected areas of the east and south spray fields, where concentrations of metals were detected above two times background concentration in soil samples during Phase I, were also sampled and submitted for laboratory analysis for metals. Based on historical documentation of site operations and the results of the Phase I investigation, soils outside of the process area have not been significantly impacted by VOCs.

Dames & Moore monitored the drilling of Phase II soil borings by Walton Corporation of Newark, Delaware between April 16 and May 16, 1991. Dames & Moore collected samples in May 1991. Each soil sample collected during the Phase II soil investigation was submitted to ETC of Edison, New Jersey for laboratory analysis. Laboratory analytical procedures required for specific samples that could not be performed by ETC were subcontracted to alternate laboratories. The Quality Assurance Project Plan (QAPP) issued by ETC for the Revere Chemical Site Phase II Remedial Investigation/Feasibility Study (RI/FS) Work Plan was approved by USEPA before initiating the collection and analysis of laboratory samples.

The Phase II soil investigation for metals involved the collection of soil samples using 3-inch (outside diameter) stainless steel split-spoon samplers. Samples were collected at the intersections of the north and east 200-foot by 200-foot grid coordinates established for the site. Sample collection locations based on the grid coordinate system provided a non-biased sampling approach that was designed to provide representative data for the site. Additional samples were collected from areas identified during the Phase I investigation that contained elevated metals concentrations, such as former site facilities, to define the level and extent of these metals in site soil (1).

The Phase II soil investigation for metals included the collection of soil samples from 73 locations cited on the 200-foot by 200-foot grid coordinate system, and 32 locations within the boundaries of the former site facilities, including the former process lagoons, storage lagoons, collection basins, sump pit, Process Refuse Area and waste lagoon (Figure 5). A discussion of background samples, east and south spray field samples and process area samples follows:

Tables 2c and 2d indicate maximum concentrations of contaminants of concern in Phase II and Figure 5 indicates the sample locations.

Table 2c. Maximum Contamination Concentration in Selected Areas in Phase II
(Interval A) Soil Sampling (1)

Table 2d. Maximum Contamination Concentration in Selected Areas in Phase II
(Interval B) Soil Sampling (1)

Metals Partitioning Study

To determine the potential for mobilization of metals in the site soils due to rainfall infiltration to potentially impact groundwater, a metals partitioning study was conducted as part of the Phase II soil investigation. The technical aspects of this study are beyond the scope of this public health assessment. However, the findings indicated that the metals mobilization related to rainfall infiltration through the overburden soil column is minimal. The results, in summary, indicated that soils contaminated with metals did not greatly affect the groundwater (1). Five soil samples were taken in April 1991 and analyzed for designated geochemical parameters by Core Laboratories of Aurora, Colorado.

Soil Gas Survey

Dames & Moore retained Tracer Research Corporation (Tracer) to conduct a soil gas survey to delineate the extent of VOC contamination in the process area. The soil gas survey was conducted at the site from October 15 through November 2, 1990. Soil gas data were collected at approximately 290 locations and analyzed for the following seven compounds: trichloroethene (TCE), tetrachloroethene (PCE), 1,1,1-trichloroethane (TCA), benzene, toluene, ethylbenzene and xylenes. The soil gas samples were analyzed by Tracer immediately after collecting each soil gas sample. These compounds were selected for analysis because they were among the most frequently detected VOCs in Phase I soil samples and are amenable to the soil gas survey technique, due to their relatively high volatility and low solubility. The concentrations detected were below levels of concern (1).

B. Off-Site Contamination

Groundwater - Residential Wells

The Bucks County Health Department collected samples from three residential wells on April 2, 1985. Analyses of the samples indicated that the following constituents were present: (1) nickel was detected in all three residential wells sampled; (2) arsenic was detected above the minimum detection limit (MDL) in one of the three residential well samples; (3) the VOCs TCE and TCA were detected in one residential well sample (1). However, the validity of the data is questionable because of the lack of supporting documentation such as field sampling and laboratory analytical procedures and protocols, and analytical results for quality assurance/quality control samples analyzed concurrently with the referenced water sample (1).

ATSDR expressed concern regarding the contaminants in these three residential wells. Based upon these concerns, the USEPA requested that these three wells be sampled during the Phase II RI. There was conflicting information regarding the homeowners' names and mailing addresses caused by two of the residents names being almost identical. Consequently, four wells, instead of three, were sampled. Figure 6 indicates persons involved in the residential well survey and residence numbers 9, 10, 26 and 42 indicate the wells sampled. Dames & Moore collected the samples in June 1991 and the samples were analyzed by the ETC Corporation for: TCL, VOCs, TAL metals and hexavalent chromium. Nickel was not detected in any well samples. Arsenic was found above the contract-required detection limit (CRDL) in two wells. The maximum concentration was 32.0 µg/L in a filtered sample in well number 9 (note: an unfiltered sample would have been preferable because that is more representative of what people actually consume). 1,1,1-Trichloroethane was found below the detection limit at an estimated value of 3 µg/L in well number 10. The maximum concentration for the contaminants of concern are indicated in Table 3.

Table 3. Maximum Contaminant Concentration in Selected Residential Wells (1)

Groundwater - Cotner Trailer

Dames & Moore collected a groundwater sample from the well at Cotner Trailer which is adjacent to the site to the north. This sample was collected in June 1991 and analyzed by the ETC Corporation for TCL VOCs, TAL metals and hexavalent chromium. Figure 2 shows the location of Cotner Trailer. None of the contaminants of concern were detected in the Cotner well with the exception of lead which was found at 7.9 µg/L in an unfiltered sample and 3.97 µg/L in a filtered sample.

Fresh-Water Pond Investigation

A man-made pond (referred to as the fresh-water pond), approximately 150 feet long and 100 feet wide, is located in the northern portion of the process area.

On October 17, 1990, one sediment sample was collected from the northwest corner of the fresh-water pond. The sample was collected by advancing a stainless-steel hand auger into the sediment to a depth of 8 inches. The sediment sample was analyzed by Environmental Testing and Certification (ETC) Corporation of Edison, New Jersey for: (1) TCL parameters, including VOCs, AEs, B/Ns, pesticides and PCBs and (2) TAL parameters, including metals and total cyanide. TAL metals were not detected in the sediment sample at concentrations that were distinguishable from background soil concentrations. No B/Ns, AEs, pesticides or PCBs were detected in the samples. No VOCs were detected that were believed to be related to metals reclamation at the site. Methylene chloride (8 micrograms per kilogram [µg/kg]) and acetone (75 µg/kg) were detected in the pond sediment sample.

On October 17, 1990, two aqueous samples (one filtered and one unfiltered) were collected from the northwest corner of the fresh-water pond. The samples were collected by immersing the sample bottle into the pond water at a point as close to the mid-depth of the pond as possible. The samples were analyzed by ETC Corporation. The unfiltered sample was analyzed for TCL parameters, including VOCs, AEs, B/Ns, pesticides and PCBs, or TAL parameters, including metals and hexavalent chromium. The filtered sample was analyzed for TAL metals (dissolved), total cyanide and hexavalent chromium.

No VOCs, AEs, B/Ns, pesticides or PCBs were detected in the aqueous samples. The unfiltered and filtered aqueous samples collected contained TAL metals. However, the concentrations of the TAL were below Federal Primary Drinking Water Standards (1).

The fresh-water pond was established and approved by the USEPA as a suitable source for decontamination water for field activities.

Ecological Investigation

The Phase II ecological investigation included: a wetlands delineation; a survey for threatened and endangered species; a study of the aquatic community in the surface water bodies at the site; a study of the terrestrial plant communities in the spray fields; and toxicity tests performed on spray field soil, stream sediment, and surface water. A summary of this comprehensive study follows.

The aquatic community survey indicated that there was some adverse impact to the benthic community on-site, but this decreased with distance from the process. No adverse impact to the benthic community was evident in Rapp Creek (1).

The terrestrial plant community survey revealed that there was no detectable toxic effect from the soil in the spray fields on the plant communities.

Sediment and surface water analysis was performed. No VOCs or PCBs were detected in stream sediment samples or in stream water samples. Maximum concentrations in ppm for stream sediments indicated beryllium at 10.2, chromium at 336 and lead at 51. Beryllium and chromium (trivalent and hexavalent) were not detected in surface water samples. Lead was found at a maximum of 8.3 µg/L in one filtered sample.

C. Quality Assurance and Quality Control

Four types of quality assurance/quality control (QA/QC) samples were collected during the Phase I RI: (1) trip blanks, (2) field (equipment rinsate) blanks, (3) replicate samples and (4) matrix spike and matrix spike duplicate samples.

The purpose of the trip blanks was to investigate the potential influence of sample bottle preparation and sample handling procedures upon the concentrations of VOCs detected in the actual samples. The purpose of the field blanks was to investigate whether or not the sampling devices and procedures may have introduced additional analytes into the samples. The purpose of the replicate samples was to assess the degree of homogeneity of the samples and the precision of the sampling procedures. The purpose of the matrix spike and matrix spike duplicate samples was to evaluate the analytical performance of the laboratory with respect to the sample matrices.

The samples collected at the Revere Chemical site during the Phase II RI were analyzed in accordance with the protocols and procedures established in the USEPA Contract Laboratory Program (CLP) Statements of Work (SOW) for Organics Analysis (1990) and Inorganics Analysis (1990), when applicable. In addition, the Phase II RI included the analysis of specific samples for non-CLP parameters. For these analyses, USEPA analytical methodologies were utilized.

Samples collected during the Phase II RI were submitted to the ETC in Edison, New Jersey. Laboratory analyses that utilize CLP methodologies, where applicable, were performed by ETC. Some samples collected during the Phase II RI required analysis for parameters that ETC does not have the capabilities to perform. These samples were subcontracted by ETC to alternative certified analytical laboratories. The analytical parameters that required the services of subcontractor laboratories were asbestos, hexavalent chromium, grain-size analysis, and total organic carbon.

The laboratory Quality Assurance Project Plan (QAPP) prepared by ETC for the Phase II RI for the Revere Chemical site was submitted to the USEPA prior to the initiation of field sampling and related laboratory analysis. A list identifying the subcontract laboratories to be used for the laboratory analyses that could not be analyzed by ETC was also provided to USEPA for review. The laboratory QAPP and the subcontract laboratory lists were both approved by USEPA before the Phase II field investigation commenced.

Based on the quality assurance review, qualifier codes were placed next to specific sample results in the on-site and off-site contamination tables presented in the "Environmental Contamination and Other Hazards" section. The PADOH believes that the qualifier codes provide an indication of the qualitative and quantitative reliability of the data presented in this public health assessment. The analyses and conclusions in this health assessment are valid only if the referenced information is complete and reliable.

D. Physical and Other Hazards

Approximately 25 acres of the site, which contained the former process area, were observed to be secured with a chainlink fence. Several dilapidated buildings remain; however, they are not accessible without gross trespassing violations.

PATHWAY ANALYSES

To determine whether residents are exposed to contaminants migrating from the site, PADOH and ATSDR evaluate the environmental and human components that lead to human exposure. A pathway consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and a receptor population.

PADOH and ATSDR identify exposure pathways as completed, potential or eliminated. Completed pathways include all five elements and indicate that exposure to a contaminant has occurred in the past, is currently occurring or will occur in the future. Potential pathways, however, have at least one of the five elements missing, but it could exist. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. Eliminated pathways have at least one of the five elements missing and it will never be present. Completed and potential pathways, however, may be eliminated when they are unlikely to be significant.

A. Completed Exposure Pathway

There are no known completed exposure pathways related to the site.

B. Potential Exposure Pathway

There is a remote potential for migration of on-site contaminants to migrate to off-site residential wells. Site-related contamination is largely confined to the former process area. TCB was not detected in any residential well tested and TCE was detected at an estimated 2 µg/L. Contamination to TCE and TCB was found in MW-4 in Phase II groundwater sampling at 110 µg/L and 41 µg/L respectively. Neither TCE nor TCB were detected in the groundwater sample collected from MW-11, which is located approximately 150 feet away from MW-4 in a downgradient direction. Nonetheless, there is a potential for these contaminants to migrate off-site and impact a small number of residential wells.

Lead was found in several off-site residential wells. The source of the lead contamination was not determined; however, it was not believed to be related to the site. The maximum lead concentration was found in a well determined to be upgradient of the site. Household plumbing could contribute to this contamination. This well was also found to have higher concentrations of other organics not related to the site. The presence of lead is a public health concern and will be discussed in the Public Health Implications section.

A detailed assessment of the hydrogeology at the site is necessary to determine if groundwater contamination pathways can reach off-site residential wells.

The primary porosity and associated permeabilities of the Lockatong and Brunswick formations are very low. However, the development of fractures in the bedrock can increase permeability through secondary porosity. Fractures in the Lockatong formation in the site vicinity provide a pathway for groundwater migration through the local bedrock, resulting in the formation of a workable aquifer (1).

The fracture trend analysis conducted during the Phase 1 RI identified two sets of preferred fracture orientations at the site. However, these fracture zones could not be traced across the site, and, in fact, were not identified in adjacent wells. Thus, the frequency of bedrock fractures appears to be randomly distributed throughout the site, although preferred fracture orientations exist at the site. In addition, the television surveys and geophysical analyses indicated that groundwater flow beneath the site is directed by both horizontal and vertical fractures (1).

The groundwater flow at the site has not been positively confirmed. This was reported in the Phase 1 RI when it was noted that the five monitoring wells in the process area did not provide sufficient data for the construction of an accurate groundwater elevation contour map (2). Precise groundwater flow could not be ascertained through the Phase 2 study when additional wells were installed. Consultation was received from the PADOH Hydrogeologist and he felt that there was not sufficient wells at shallow, intermediate and deeper zones to properly assess groundwater flow. His review of the hydrogeological maps provided and monitoring well data indicated that information was insufficient to determine groundwater flow (11).

A Phase 2A Groundwater Investigation is underway. The Phase 2A scope of work focuses on: (1) confirming the source of recharge water that is producing the groundwater mound, (2) evaluating static groundwater flow conditions, and (3) confirming the limited extent and degree of compounds detected in two of the groundwater monitoring wells. This will include residential well sampling near the site.

A recent discussion with the USEPA Remedial Program Manager indicated that site-related contaminants have not been found in recently tested off-site residential wells. However, this study has not yet been finalized and summarized so that groundwater flow and residential well sampling results remain a data gap until the Phase 2A investigation is complete and the findings reviewed (12).

Groundwater contamination in on-site monitoring wells is not extensive; however, if any migration of site contaminants is occurring, it would most likely occur in the wells west and southwest closest to the site. The number of persons potentially affected would be small. (See Figure 6).

There is a potential for TCE and TCB to migrate off-site; therefore, these contaminants will be discussed in the Public Health Implications section.

The "process area" of the site is fenced and not accessible to the public. Soil contamination was mostly limited to this area, and generally, repeated sampling rounds indicated that contaminant levels decreased with distance from the process area. The spray fields are revegetated and the majority of samples taken from these areas were non-detect for VOCs and B/Ns. The soil pathway can be eliminated as a public health concern to off-site residents.

PUBLIC HEALTH IMPLICATIONS

A. Toxicologic Evaluation

Introduction

In this section, we will discuss the health effects in persons exposed to specific contaminants. The USEPA developed Maximum Contaminant Levels (MCLs) for drinking water. Primary MCLs are federal drinking water standards declared under the Safe Drinking Water Act. Generally, an MCL for a toxic chemical represents the allowable lifetime exposure to the contaminant for a 70-kg adult who is assumed to ingest 2 liters of water per day. In addition to health factors, an MCL is required by law to reflect the technological and economic feasibility of removing the contaminant from the water supply. The limit set must be feasible given the best available technology and treatment techniques. USEPA's Reference Dose (RfD) is an estimate of the daily exposure to a contaminant that is unlikely to cause adverse health effects. ATSDR has developed Minimal Risk Levels (MRLs) for contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to aa contaminant below which non-cancer, adverse health effects are unlikely to occur.

As mentioned in the Pathways Analysis section, there are three contaminants retained for toxicological evaluation. They are lead, TCE and TCB.

Lead

Lead was found in one filtered sample at a level of 25.1 µg/L in a residential well. The current Maximum Contaminant Level Goal (MCLG) for lead is zero. As previously indicated, an unfiltered sample is preferable to obtain actual levels ingested. While ATSDR has no MRLs and USEPA has no RfD for lead, this lead exposure of 25.1 µg/L should be reduced to the lowest level possible (at least below USEPA's proposed guideline of 15 µg/L at the tap). High blood lead levels are associated with a decrease in intelligence quotient (IQ) scores, slow growth and hearing problems. Lead exposure is especially dangerous for unborn children because they can be harmed during fetal development. Pregnant women exposed to lead can transfer lead to unborn children, causing premature birth, low birthweight and miscarriages (13). The level of lead found in this residential well (25.1 µg/L) would not likely cause any of the adverse health outcomes cited above.

Trichloroethylene (TCE)

TCE exposure has not occurred and is not occurring to off-site residents via any media. Currently, there is no chronic MRL or RfD available for this chemical.

TCE was found in an on-site monitoring well at 110 µg/L; however, there was no indication that this TCE was migrating. In the event that the TCE found on-site would migrate to a residential well and if exposure occurs at that level, adverse health effects may occur from chronic exposure (e.g., cancer).

Occupational studies of workers exposed to TCE (levels which are much higher than the levels found in the environment) have not detected TCE-induced cancer, while some animal studies have shown that TCE can produce lung and liver cancer (14). Animal studies also have shown that TCE can cause leukemia, a cancer of the tissues that form white blood cells. In reviewing the animal studies, the Department of Health and Human Services (DHHS) National Toxicology Program could not find clear evidence that TCE causes cancer in animals. The International Agency for Research on Cancer (IARC), an agency which classifies chemicals for their carcinogenicity, has decided that TCE is not classifiable as to human carcinogenicity. USEPA, which also classifies the carcinogenicity of chemicals, classified TCE as a probable human carcinogen. However, USEPA is currently reviewing the carcinogenicity of TCE. There is uncertainty prevailing among the scientific community with regard to the carcinogenicity of this chemical.

The nervous system is probably the most sensitive system that will show adverse health effects from chronic exposure to TCE (12). However, it is unlikely that this health effect would occur at the level detected on-site.

1,2,4-Trichlorobenzene

There has been no known human exposure to 1,2,4-trichlorobenzene (TCB) related to the Revere Chemical site. However, TCB was found in MW-4 on-site at a concentration of 41 µg/L. The proposed MCL is 9 µg/L. If TCB migrates to off-site residential wells and if exposure occurs at the level found on-site, then some health effects can occur (e.g. irritation of skin, nose and throat) (15).

There is no evidence that TCB is migrating and even if no further remediation is done on-site, regular testing of nearby residential wells should prevent any exposure that would cause adverse health effects.

B. Health Outcome Data Evaluation

All residents in the vicinity of the site depend on private wells for their water supply. There was no evidence of site-related contaminants in the closest well to the site (Cotner Trailer). There were no site-related contaminants of concern in several residential wells that were recommended for a retest in the RI/FS. There were no community concerns associated with morbidity or mortality so no health outcome data bases were evaluated.

C. Community Health Concerns Evaluation

We have addressed the community concerns about health as follows:

Based on the information reviewed, PADOH has concluded that this site is an indeterminate public health hazard. Available data do not indicate that humans are being or have been exposed to levels of contaminants that would be expected to cause adverse health effects. However, groundwater flow has not been fully characterized and not all residential wells in close proximity of the site have been tested. Residential well testing has been completed under the Phase 2A Groundwater Investigation and the outcome is under review (12). The highest on-site contamination occurred in the "process area" of the site and this area is fenced and not accessible to the public. There were no community health concerns regarding mortality or morbidity.

Lead was found in an upgradient residential well above the USEPA proposed guideline of 15 µg/L at the tap. This represents a non-site-related public health problem.

RECOMMENDATIONS

Site Characterization Recommendations

Health Activities Recommendations Panel (HARP) Recommendations

PUBLIC HEALTH ACTIONS

The Public Health Action Plan (PHAP) for the Revere Chemical site contains a description of actions to be taken by ATSDR and/or PADOH at and in the vicinity of the site subsequent to the completion of this public health assessment. For those actions already taken at the site, please see the Background section of this public health assessment. The purpose of the PHAP is to ensure that this public health assessment not only identifies public health hazards, but provides a plan of action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment. Included, is a commitment on the part of ATSDR/PADOH to follow-up on this plan to ensure that it is implemented. The public health actions to be implemented by ATSDR/PADOH are as follows:

1. PADOH will continue to review off-site residential well sampling data to determine if any site-related contaminants are migrating.

    

2. ATSDR will provide a follow-up to this PHAP, outlining the actions completed and those in progress. This report will be placed in repositories that contain copies of this public health assessment, and will be provided to persons who request it.

ATSDR will reevaluate and expand the Public Health Action Plan when needed. New environmental, toxicological, or health outcome data, or the results of implementing the above proposed actions may determine the need for additional actions at this site.

PUBLIC COMMENTS AND RESPONSE

A comment was received which provided clarification and a minor editorial correction to the report. A minor editorial correction was made to the off-site contamination section of the report based on the clarification received.

PREPARERS OF REPORT

Thomas Hartman
Statistician
Pennsylvania Department of Health

Kandiah Sivarajah, Ph.D.
State Toxicologist and Project Director
Pennsylvania Department of Health

ATSDR Regional Representative:

Charles Walters
Public Health Advisor
USEPA Region III
Office of the Assistant Administrator

ATSDR Technical Project Officer:

Gregory Ulirsch/Gail Godfrey
Technical Project Officers
Remedial Program Branch
Division of Health Assessment and Consultation
 

CERTIFICATION

This Revere Chemical Company Public Health Assessment was prepared by the Department of Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health assessment was begun.

Gail Godfrey
Technical Project Officer
Remedial Programs Branch
Division of Health Assessment and Consultation (DHAC)
ATSDR

The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health assessment, and concurs with its findings.

Robert C. Williams, P.E., DEE
Director, DHAC, ATSDR
 

REFERENCES

1. Phase II Remedial Investigation Draft Report, Revere Chemical Site, Nockamixon Township, Pennsylvania, Dames & Moore, October 21, 1991.

    

2. Phase I Remedial Investigation, Revere Chemical Site, Nockamixon Township, Pennsylvania, Dames & Moore, March 14, 1990.

    

3. Summary of General Population Characteristics 1990, Census of Population and Housing, 1990; Summary Tape File 1A, U.S. Department of Commerce, Bureau of the Census, June 1991.

    

4. Agency for Toxic Substances and Disease Registry. Draft Health Assessment for Revere Chemical Company, Revere, Bucks County, Pennsylvania, 1988.

    

5. Public Schools, Elementary Enrollments, 1990-1991, Pennsylvania Department of Education, 1991.

    

6. Public Schools, Secondary Enrollments, 1990-1991, High School Graduates, 1989-1990, Pennsylvania Department of Education, 1991.

    

7. Nursing Home Directory, State Health Data Center, Pennsylvania Department of Health, December 1990.

    

8. Directory of Pennsylvania Hospitals, State Health Data Center, Pennsylvania Department of Health, December 1990.

    

9. Rand McNally & Company, Pennsylvania, Commercial Reference Map and Guide, 1983.

    

10. Telephone Conversation with Ruth Rzepski, Remedial Program Manager, U.S. EPA, June 19, 1992.

     

11. Hydrogeological Evaluation by J.E. Godfrey, Hydrogeologist, Pennsylvania Department of Health, August 1992.

     

12. Telephone Conversation with Ruth Rzepski, Remedial Program Manager, U.S. EPA, August 1992.

     

13. Agency for Toxic Substances and Disease Registry, Toxicological Profile for Lead. Atlanta, Georgia; Agency for Toxic Substances and Disease Registry, June 1990, DHHS Publication No. (PHS) TP-88-17.

     

14. Agency for Toxic Substances and Disease Registry, Toxicological Profile for Trichloroethene, U.S. Public Health Service, Atlanta, Georgia, October 1989.

     

15. Sittig, Marshall. Handbook of Toxic and Hazardous Chemicals and Carcinogens, 3rd Edition, Noyes Publication, 1991.

APPENDIX A. Figures

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.
 

APPENDIX B. Tables

This Appendix was not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact: