BASELINE RISK ASSESSMENTThe objective of this Baseline Risk Assessment is to evaluate the potential...

BASELINE RISK ASSESSMENT

FOR

ELECTRO-COATINGS INC. SITE

CEDAR RAPIDS, IOWA

Prepared by:

Iowa Department of Natural Resources Solid Waste Section

Des Moines, Iowa

May 1993 Revised July 1993

30225936

Superfund

TABLE OF CONTENTSINTRODUCTION.................................................................................................................................................. 3

Overview................................................ 3Site Background......................................................................................................................................... 3Scope of Risk Assessment ....................................... 5

IDENTIFICATION OF CHEMICALS OF POTENTIAL CONCERN.......................................................... 5Data Collection......................................................................................................................................... 5Evaluation of Data..................................................................................................................................... 6Summary of Chemicals of Potential Concern......................................................................................... 7

EXPOSURE ASSESSMENT ................................................................................................................................ 8Characterization of Exposure Setting .................................................................................................... 8Identification of Exposure Pathways ...................................................................................................... 9Quantification of Exposure.................................................................................................................... 11

Table 1: Potential Contaminant Concentrations in Drinking Water ................................. 12Table 2: Estimated Intake Via Drinking Water ................................................................. 13Table 3: Estimated Intake Via Inhalation............................................................................. 14

Exposure Uncertainties ......................................................................................................................... 15

TOXICITY ASSESSMENT ................................................................................................................................ 15Toxicity Information for Non-Carcinogenic Effects ........................................................................... 16

Table 4: Toxicity Values for Potential Non-Carcinogenic Effects ..................................... 16Toxicity Information for Carcinogenic Effects .................................................................................... 16

Table 5: EPA Weight of Evidence Classification System for Carcinogenicity ................ 17Table 6: Toxicity Values for Potential Carcinogenic Effects ............................................ 17

Uncertainties Related to Toxicity Information.................................................................................... 18

RISK CHARACTERIZATION ......................................................................................................................... 18Current Land-Use Conditions................................................................................................................ 18Future Conditions .................................................................................................................................. 18

Table 7: Cancer Risk Estimates ........................................................................................... 19Table 8: Chronic Hazard Index Estimates ........................................................................... 20Table 9: Subchronic Hazard Index Estimates ...................................................................... 21

Uncertainties........................................................................................................................................... 22Summary Discussion of Risk Characterization.................................................................................... 22

SUMMARY ......................................................................................................................................................... 23Chemicals of Potential Concern ........................................................................................................... 23Exposure Assessment.............................................................................................................................. 23

Table 10: Observed and Regulatory Groundwater Concentrations ................................... 24Toxicity Assessment................................................................................................................................ 24Risk Characterization.............................................................................................................................. 24

Table 11: Summary of Assessed Risks .................................................................................. 25Ecological Assessment........................................................................................................................... 25

Figure 1 - Location Map ................................................................................................................................... 26Figure 2 - Chromium VI in Groundwater ........................................................................................................ 27Figure 3 - TCE and PCE in Groundwater ..................................................................................................... 28

ATTACHMENT A : Pre - 1986 Analytical Data ........................................................................................... 29ATTACHMENTS B : Analytical Data from the 1986 Site Inspection .......................................................... 31ATTACHMENTS : Compilation of Analytical Data from the Remedial Investigation ............................ 33

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BASELINE RISK ASSESSMENT FOR

ELECTRO-COATINGS, INC. SITE CEDAR RAPIDS, IOWA

1.0 INTRODUCTION

1.1 overviewThe Electro-Coatings site has been investigated due chromium contamination of groundwater. In 1976 high levels of chromium were discovered in groundwater from a nearby cooling water well of the Hawkeye Rubber Company. Recent investigations of groundwater have also revealed chlorinated hydrocarbon contamination of groundwater, much of which has been found to originate from the Hawkeye Rubber Company. The primary concern regarding the site has been potential contamination of city wells. The closest city well is about 2,000 feet west of the site. Chromium contamination has not been found in any City well. The site is adjacent to Cedar Lake which previously received the discharge from the Hawkeye Rubber cooling water well. No significant contamination of Cedar Lake has been attributed to this site. Recent investigations by Electro- Coatings have demonstrated that the Hawkeye Rubber Co. cooling water well largely contains groundwater contaminants associated with the site.

The objective of this Baseline Risk Assessment is to evaluate the potential adverse health effects (current and future) caused by releases of hazardous substances from the site in the absence of any actions to control or mitigate these releases. This risk assessment will not address the organic contamination attributed to the Hawkeye Rubber Company.

12 Site BackgroundThe site is located at 911 Shaver Road NE in the City of Cedar Rapids in east-central Iowa (Figure 1). The site occupies approximately one acre along the north shoreline of Cedar Lake. The area surrounding the site is urban. The immediate area is light-industrial. Cedar Lake is a 150 acres in size and is privately owned by a utility company for cooling water.

Electro-Coatings, Inc. is a nationwide corporation whose headquarters is located in Emeryville, California. The Electro-Coatings plant in Cedar Rapids has been in operation since 1947. The plant currently performs chromium, cadmium, nickel and zinc plating.

In March of 1976 a yellow tinge was noted in the cooling water being discharged to Cedar Lake from the Hawkeye Rubber Company. The Hawkeye Rubber Company is located immediately west of Electro-Coatings. Hawkeye Rubber Company had two cooling water wells which discharged into Cedar Lake. Shortly after the chromium contamination was discovered, the cooling water discharges were moved to the sanitary sewer. The chromium contamination does not pose a problem for Hawkeye Rubber and in fact may have some benefit since chromium is commonly used as a rust and corrosion inhibitor.

The chromium contamination was attributed to the release of chromic acid from a concrete tank at Electro- Coatings plant. In response to requirements by the State, Electro-Coatings took actions to prevent further releases. Electro-Coatings installed five monitoring wells which they monitored periodically in addition to the Hawkeye Rubber cooling water well. The main concern has been potential chromium contamination of the City of Cedar Rapids municipal wells; the closest of which is about 2,000 ft. west of the site. Over the years contamination was found to persist, albeit in lower concentrations, in the Hawkeye Rubber cooling water well. Significant chromium contamination has only been found in one of the five monitoring wells; the well adjacent to the plant. No evidence of chromium contamination has been found in the City wells.

In June of 1988 the Electro-Coatings site was proposed for inclusion on the Superfund National Priorities List (NPL) and that listing became final in October of 1989. In January 1990 Electro-Coatings, Inc. entered into a consent order with the Iowa Department of Natural Resources (DNR) for conducting a remedial investigation/feasibility study (RI/FS) of the site.

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In 1986 a fish consumption advisory was issued for Cedar Lake due to high levels of chlordane found in fish from Cedar Lake. This has nothing to due with the contaminants associated with the Electro-Coatings site. The result? of a 1984 limnological study of Cedar Lake which included analyses of metals in sediment from Cedar Lake o .ucluded the following. "Relatively high concentrations of heavy metals were present in the lake sediments but they are unlikely to have a significant impact on the lake fishery unless dredging operations or other activities resulted in resuspension of appreciable amounts of sediment. The fact that Cedar Lake supports a relatively diverse and productive fishery indicates that the presence of heavy metals or other toxic materials in the sediments are not currently adversely impacting the present fish populations." It should be noted that the reference to relatively high concentrations of heavy metals is with respect to background levels not levels of health-based concern.

The following is a summary of findings from the remedial investigation:

1) The site is underlain by variable thicknesses of sand and silty clay over Silurian dolomite. Towards the south the silty clay layer becomes predominantly silt. The silty clay appears to be very thin or non-in the vicinity of monitoring well #MW-7, possibly providing a zone for shallow contaminants to move down to the bedrock aquifer.

2) Chromium contamination of groundwater has been found primarily in the area between the Electro- Coatings plant and the Hawkeye Rubber well #PW-1. Figure 2 shows the chromium contamination plumes in the sand aquifer and the bedrock aquifer. Chromium contamination exists in the sand aquifer close to the Electro-Coatings plant but is drawn down to the bedrock aquifer by the Hawkeye Rubber production well #PW-1. It appears that movement of chromium contaminated groundwater in the sand aquifer to bedrock aquifer is facilitated by the lack of the silty clay confining layer as identified near monitoring well #MW-7. Elevated levels of chromium have been detected in the sand aquifer west of PW-1, but in much lower concentrations than found in east of PW-1 and in PW-1. Therefore, it has been concluded that PW-1 contains the majority of the chromium contamination from the Electro- Coatings site.

3) Hexavalent chromium is the predominant contaminant found in site groundwater which is associated with the Electro-Coatings facility. The chromic acid used by Electro-Coatings for plating contains hexavalent chromium. Concentrations of hexavalent chromium as high as 25 mg/1 have been found in site groundwater compared to the drinking water standard of 0.1 mg/1. Other inorganic compounds have been found in site groundwater including, cadmium, cyanide, nickel, and lead. Unlike chromium, these compounds have been detected at concentrations which are below or only slightly above drinking water standards.

4) Volatile organic compounds (VOCs) have also been found in site groundwater at levels substantially above drinking water standards, including: tetrachloroethene; trichloroethene; and cis 1,2-dichloroethene. Most VOC contamination has been attributed to the adjacent Hawkeye Rubber Company which utilized tetrachloroethene for vapor degreasing until recently. Trichloroethene and cis 1,2-dichloroethene are breakdown products of tetrachloroethene, thus accounting for their occurrence. Electro-Coatings has reportedly utilized trichloroethene and 1,1,1-trichlororethane and a portion of the overall VOC contamination associated with these compounds appears to be attributed to the Electro-Coatings facility. Figures 3 and 4 show the trichloroethene (TCE) and tetrachloroethylene (PCE) plumes in the shallow sand aquifer. Like the chromium contamination, the majority of the VOC contamination in groundwater appears to be drawn into the Hawkeye Rubber well PW-1.

5) Soil sampling conducted as part of the remedial investigation has not revealed significant chromium contamination. However, during plant modifications in the summer of 1992, another chromium leak was found at the Electro-Coatings plant. Contaminated soil associated with the leaky tank was excavated and disposed of in a hazardous waste landfill. Some residual soil contamination was left in place.

6) Soil sampling has revealed significant VOC contamination in the vicinity of the Hawkeye Rubber Co. plant. However, only very low concentrations of VOCs were identified in soils adjacent to the Electro- Coatings plant.

7) Sampling of water and sediments from Cedar Lake has not revealed any significant impact from the site.

13 Scope of Risk AssessmentThe scope of this Baseline Risk Assessment is limited to potential risks to human health and the environment because of exposure to contaminants from the Electro-Coatings, Inc. site. The situation at the Electro-Coatings site is relatively straightforward. Chromium contamination of groundwater has existed for at least sixteen years. Other groundwater contaminants have been identified and will be evaluated but hexavalent chromium in groundwater is the primary focus of the risk assessment.

In the process of investigating the Electro-Coatings site, significant volatile organic contamination was also discovered. However, it has been determined that the bulk of this volatile organic contamination is not associated with the Electro-Coatings facility; instead the adjacent Hawkeye Rubber facility has been identified as the source. The volatile organic contamination associated with the Hawkeye Rubber facility will not be addressed in this risk assessment.

This risk assessment has been prepared in accordance with guidance procedures for risk assessments at hazardous waste sites developed by the U.S. Environmental Protection Agency (EPA). The primary guidance used was the Risk Assessment Guidance for Superfund (RAGS), Volume I (Human Health Evaluation Manual) 1989.

The risk assessment includes four major sections as follows:1) An identification of the chemicals of potential concern, including a summary of available data;2) An assessment of the potential exposure to the chemicals of concern, including the pathways for

exposure and the amount of exposure;3) An assessment of the toxicity of the chemicals of concern; and4) A characterization of the risks associated with the potential exposure to the chemicals of concern.

2.0 IDENTIFICATION OF CHEMICALS OF POTENTIAL CONCERN

2.1 Data CollectionData have been collected at this site by several parties. The Iowa Department of Environmental Quality, a predecessor of the present Environmental Protection Division of the Iowa Department of Natural Resources (DNR), initially evaluated the site in the late 1970’s. Electro-Coatings frequently monitored the Hawkeye Rubber production wells #PW-1 and #PW-2 for chromium from March 1976 through August 1979. Monitoring wells #MW-1 and #MW-2 were monitored for chromium several times in 1978 after they were initially installed. Another flurry of sampling, which included monitoring wells #MW-3 and #MW-4 in addition to the wells mentioned previously, occurred in 1983. Monitoring well #MW-5 (referred to as MW-11 in the Remedial Investigation) was installed and sampled in 1985. All of this monitoring was for chromium only. Several of the samples were collected by the state with analyses by the University of Iowa Hygienics Laboratory (UHL), although most samples were collected by Electro-Coatings with analyses by the City of Cedar Rapids Water Pollution Control plant or a local private laboratory (Sanlabs).

In October of 1986, the Iowa DNR conducted a Site Inspection (SI) at the Electro-Coatings facility. Groundwater samples were collected from the two Hawkeye Rubber production wells, five Electro-Coatings monitoring wells, a 7-ft. deep private well located about 1500 feet east of the site, and City Well #1 in the East Well Field located about 2400 feet west of Electro-Coatings. Two each surface water and sediment samples were also collected from Cedar Lake. In additional to total and hexavalent chromium, these October 1986 samples were also analyzed for cyanide and cadmium. Samples collected during the 1986 SI were analyzed by UHL.

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Electro-Coatings collected a few samples after the October 1986 sampling event, but a significant amount of sampling was not conducted again until the summer of 1990. In August 1990 Electro-Coatings sampled monitoring wells #1 - 4 for total chromium. In September 1990 the DNR collected screening samples from a temporary well point at four locations as well as samples from monitoring well #1 - 4, both Hawkeye Rubber production wells, and Cedar Rapids City Well #6. These September 1990 samples were analyzed for total chromium only with the exception of the most contaminated well point sample for which heavy metals were also analyzed. The DNR samples were analyzed by the UHL. Electro-Coatings split samples which were analyzed by Sanlabs.

Electro-Coatings conducted their remedial investigations in three phases during 1991. Electro-Coatings used National Environmental Testing, Inc. (NET) as the primary laboratory for analyses during the RI. Some split samples were also analyzed for chromium by Sanlabs. The first phase in February and March of 1991 included: soil sampling from five borings, installation of nine monitoring wells, and sampling from the nine new and four existing monitoring wells and the two Hawkeye Rubber production wells. All samples were analyzed for total and hexavalent chromium and one sample from monitoring well #9 was also analyzed for volatile organic compounds (VOCs). A second round of groundwater sampling from the same wells was conducted in May of 1991. In addition, two sediment and two surface water samples were collected from Cedar Lake. All samples collected in the May sampling event were analyzed for total and hexavalent chromium, cadmium, cyanide, and VOCs. The sample from Monitoring Well #9 (MW-9) was also analyzed for a standard list of inorganic compounds. The third phase of remedial investigation was conducted in August and September of 1991. It involved: seven soil borings sampled for VOCs; installation of another monitoring well (MW-5D); sampling of all ten new monitoring wells, an old monitoring well (labeled MW-11), Hawkeye Rubber production well #1, and one surface water sample from Cedar Lake; and analyses of all water samples for total and hexavalent chromium and VOCs.

In spring of 1992 Electro-Coatings took a chromium dipping tank out of service and discovered a release of chromic acid. Eighteen soil samples were collected in an attempt to determine the extent of contamination. These samples were analyzed for total and hexavalent chromium.

In June of 1992, the Iowa DNR conducted a followup investigation in response the VOC contamination. This investigation primarily involved soil-gas sampling with on-site screening analyses for VOCs. In addition, four soil samples were sent for laboratory analyses of VOCs.

22 Evaluation of DataA fair amount of data exists prior to the 1986 SI. These data were obtained largely from grab samples which were collected and analyzed by various parties and with minimal documentation. Primarily chromium data were collected prior to 1986. Summaries of the pre-1986 data as presented in the SI are included as Attachment ’A’. In general, the pre-1986 data reveals valuable information about the occurrence and magnitude of chromium in Hawkeye Rubber wells PW-1 and PW-2 and in Electro-Coatings’ monitoring wells MW-1 and MW-2. However, due to the lack of documentation regarding sampling, no single piece of datum is considered to be reliable. Therefore, the pre-1986 data will not be used for detailed calculations in this risk assessment. It should be noted, however, that use of the pre-1986 data would not appreciably affect the results of this risk assessment.

Data obtained from the 1986 SI are well documented and include a duplicate and field blank sample for quality assurance (QA). The SI data also includes cyanide and cadmium analyses. The 1986 SI data are summarized in Attachment ’B\

Data collected since 1990 are believed to be of generally good quality. All the available VOC data and much of the inorganic data, other than chromium, co: ies from this period. The sampling conducted by Electro- Coatings was done in accordance with an RI/FS work plan which was reviewed by DNR. Data sheets are all included in the Administrative Record (Section 1.0 and 3.0) and a summary of the data for the chemicals of potential concern (Section 2.3 of this report) are included as Attachment ’C’. The bulk of these data were collected by Electro-Coatings in the three phases of the Remedial Investigation conducted in 1991. Quality assurance samples (i.e., duplicates and splits) have, in general, had excellent correlation as can be seen in Attachment ’C’. Blank samples (field, equipment, and trip) have revealed only minimal cross contamination.

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That is, one equipment blank sample (pure water rim through the sampling equipment) revealed 0.0032 mg/1 of methylene chloride and 0.002 mg/1 of total chromium. This cross contamination is considered to be insignificant.

Three individual pieces of data are suspect and have been discounted. The March 25,1991, groundwater sample from MW-1 revealed 0.336 mg/1 of methylene chloride. The subsequent two samples and one split sample had no detection of methylene chloride. Methylene chloride is also frequently found as a result of laboratory contamination. Two surface water samples collected on May 5, 1991, were originally reported as containing levels of total chromium above the drinking water standard. However, chromium was not detected in a split sample collected by DNR. Re-analyses of the two samples revealed errors by the laboratory. Corrected levels are below the drinking water standard.

Overall the quality of data for this risk assessment is believed to be very good. The data reveal consistent patterns of contaminant occurrence and magnitude. The older data compliments the newer data, despite being less reliable.

23 Summary of Chemicals of Potential ConcernThe sampling efforts have focused on groundwater and soils with some surface water and sediment samples also collected. The primary chemical of concern is obviously hexavalent chromium. Where significant contamination has been found hexavalent chromium essentially equals total chromium. Therefore, only hexavalent chromium will be evaluated in this risk assessment and where only total chromium data are available, the assumption will be made that hexavalent chromium concentrations equal total chromium concentrations.

Other inorganic contaminants which have been identified at significant concentrations (i.e., above drinking water standards) at this site include: cadmium, cyanide, lead, and nickel. Reportedly, a January 1983 sample from Hawkeye Rubber production well PW-1 was found to contain 0.24 mg/1 of cyanide. The presence of cyanide was attributed to a leak in the cadmium plating line which was reportedly discontinued at that time. Samples collected prior to the RI had also revealed elevated levels of cadmium, presumably also attributed to cadmium plating operations by Electro-Coatings. Analyses of cyanide and cadmium were conducted on the samples collected in the 1986 SI and May 1991 phase 2 RI. Cyanide was detected in only one of these samples; that being a sediment sample at a concentration just above the detection level. Therefore, cyanide is not believed to be a contaminant of potential concern.

Cadmium was detected in 18 of 26 groundwater samples from the 1991 RI samples, 8 of which were above the drinking water standard Maximum Contaminant Level (MCL). Therefore, cadmium is considered to be a potential contaminant of concern. Nickel was analyzed in only 4 groundwater, 2 surface water, and 2 sediment samples. Nickel levels exceeded the MCL in 3 of the 4 groundwater samples and since nickel plating is conducted by Electro-Coatings, nickel has been considered to be a potential contaminant of concern.

Lead was found in two of three groundwater samples; one slightly above and on slightly below the drinking water action level of 0.015 mg/1. Two surface water samples revealed lead at about 0.03 mg/1 each. The lead in the surface water is likely not attributed to the site. Unlike chromium, cadmium, and nickel, there is insufficient data to attribute lead found in groundwater to the site. The lead found in the monitoring well most likely to contain contamination from Electro-Coatings (MW-9) was only slightly above the drinking water action level. Therefore, lead is not believed to be a primary contaminant of concern associated with this site.

In addition to metals, VOC contamination has been identified at the site. The VOC contamination can be attributed almost entirely to solvents used by Electro-Coatings and Hawkeye Rubber. Electro-Coatings has reportedly used 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethene (TCE) at their facility. Until recently, Hawkeye Rubber has used tetrachloroethene, also called perchloroethene (PCE). These three solvents and associated breakdown products account for the bulk of the VOC contamination found at the site. Clearly TCE and 1,1,1-TCA contamination is attributed to Electro-Coatings. The highest concentrations TCE and 1,1,1-TCA in groundwater have been found in MW-9 and MW-11, both of which are located in the heart of the chromium plume adjacent to the Electro-Coatings facility. Breakdown products of TCE and 1,1,1-TCA whose detections correlate closely with TCE and 1,1,1-TCA include 1,1-dichloroethane (1,1-DCA), 1,1-dichloroethene (1,1-DCE),

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and cis 1,2-dichloroethene (C1,2-DCE). TCE, 1,1,1-TCA, 1,1-DCE, and C1,2-DCE have been selected as contaminants of potential concern for this risk assessment. All but 1,1,1-TCA have been detected in groundwater at concentrations in excess of drinking water MCLs. Levels of 1,1,1-TCA were found approaching the MCL. The compound 1,1-DCA was not chosen as a contaminant of potential concern because it was detected at low concentrations in only a few samples and little health effect data are available for this compound.

VOCs which were detected in site samples but determined not to be contaminants of potential concern (in addition 1,1-DCA) are: benzene, toluene, xylene, methylene chloride, acetone, 2-hexanone, and (as mentioned previously) PCE. Benzene, toluene, and xylene are common contaminants associated with petroleum. The levels found of these contaminants were very low and showed no particular pattern which suggested attribution to Electro-Coatings. Methylene chloride was detected in only one groundwater sample, as discussed previously in Section 2.2. Methylene chloride and acetone were identified in two soil samples adjacent to the Hawkeye Rubber facility. These contaminants were identified in only one of two sample vials for each sample and are likely an artifact of laboratory contamination. The compound 2-hexanone was found in only one groundwater sample at a low concentration. PCE is by fair the dominant VOC identified at the site. A concentration of PCE in groundwater of 15.4 mg/1 was found compared to 0.89 mg/1 for TCE and 0.16 mg/1 for 1,1,1-TCA. However, the evidence conclusively shows Hawkeye Rubber to be the source of the PCE contamination. Despite the obvious concern regarding PCE contamination, it is considered to come from a separate site and will not be addressed in this risk assessment. Hawkeye Rubber is addressing the PCE contamination. It should be noted that TCE is a breakdown product of PCE and the TCE detected in samples with high concentrations of PCE is likely attributed to this. Semi-volatile organic compounds, pesticides, and PCB were analyzed in one sample from MW-9 with none detected. There is no reason otherwise to suspect contamination from these compounds at this site.

In summary, the contaminants of potential concern at the Electro-Coatings site are:

Hexavalent ChromiumCadmiumNickel1.1- Dichloroethene Cis 1,2-Dichloroethene1.1.1- Trichloroethane TrichJoroethene

A summary of the detection of these compounds^is included as Attachment ’C’.

3.0 EXPOSURE ASSESSMENT

3.1 Characterization of Exposure SettingThe site is situated in the floodplain of the Cedar River in the City of Cedar Rapids, Iowa. The site is just north of the downtown area and on the north shore of Cedar Lake (Figure 1). The Cedar River is located about 2,000 feet southwest of Electro-Coatings. A local drainageway known as McClouds Run is located about 1,000 feet north of Electro-Coatings. McClouds run drains into Cedar Lake about 1,000 feet west of Electro-Coatings.

The site is located in an area zoned for general use industrial. The zoning description states the area so designated "is intended to accommodate those industrial activities which may produce moderate nuisances or hazards in areas that are relatively remote from residential and commercial development". The zoning designation for the site and surrounding area also does not permit dwelling units or lodging rooms. Interstate #380 separates the site from commercial and residential areas east of the site. Areas zoned residential are located 800 feet east and 1400 feet north of the site.

Cedar Lake is a 150 acre impoundment owned by the local electric utility company. The lake was developed for industrial uses but has also been used for recreation (i.e., fishing). Cedar Lake supports a relatively diverse and productive fisheries. However, high levels of chlordane (a chemical used for termite control) have been found

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in fish from Cedar Lake. In 1986 a fish consumption advisory was issued due to the chlordane found in fish from Cedar Lake. It should be noted that this advisory had nothing to do with any of the contaminants associated with the Electro-Coatings site. The most contaminated Electro-Coatings well, MW-9, did have a sample which was analyzed for chlordane and no chlordane was detected. A recreational trail which is open to the public is located along Cedar Lake adjacent to the site.

The principle groundwater resources in the vicinity consist of shallow alluvial sands and gravel and the Silurian- Devonian and Cambrian-Ordovician bedrock aquifers. At the site alluvial sands are separated from Devonian bedrock by a 2 to 17 ft. thick silty clay confining layer. The Silurian-Devonian aquifer is a productive aquifer which is heavily used locally for industrial purposes. The alluvial and Silurian-Devonian aquifers generally flow to the Cedar River the southwest although are locally drawn to the Hawkeye Rubber production well #PW-1. The Cambrian-Ordovician aquifer is about 1,000 ft. deep and is not susceptible to contamination from the Electro-Coatings site.

The City of Cedar Rapids obtains its municipal water supply from the alluvial aquifer adjacent to the Cedar River. Much of the water drawn into these alluvial wells is induced from the Cedar River. The city has three well fields, all upstream from the Electro-Coatings site. The East Well Field is the closest to the site and consists of twenty alluvial wells. The closest well is about 2,000 feet west of the site and the other wells are spread out for nearly a mile upstream along the Cedar River. The wells in the East Well Field are all about 70 feet deep and are each rated at 1,000 gallons per minute or more. The other two well fields are located upgradient of the East Well Field and are not threatened by the site. The average water use in the city is about 28 million gallons per day.

32 Identification of Exposure PathwaysCurrent Exposure Pathways: Prior to March of 1976 contaminated water was being discharged directly to Cedar Lake from the Hawkeye Rubber production wells. Exposure pathways undoubtedly existed as a result prior to that time, although there is no documentation of any significant exposure or resulting adverse impact. Recent samples have not revealed any significant lasting impact to Cedar Lake water or sediments. Since the Hawkeye Rubber cooling water system is a closed system, no contact with the contaminated water normally occurs. This cooling water is discharged to the sanitary sewer. Hawkeye Rubber uses city water for drinking and sanitary purposes. Occasional incidental contact with this cooling water is possible although is not considered to result in a significant exposure.

Contaminated soils would be a concern due to the proximity of the recreational trail as well as potential exposure to workers. However, all significant soil contamination which has been found associated with Electro-Coatings is under floors inside the plant. Partial demolition of the building would be necessary to even get to the residual contaminated soil. Shallow soils have not be sampled outside of the plant because the are surrounding the plant is all paved. Shallow soil contamination has been identified associated with the Hawkeye Rubber site. However, the area of contamination is small and mostly under pavement. Regardless, contamination attributed to Hawkeye Rubber will be addressed as part of a separate project.

There is also no evidence that air or food (i.e., fish in Cedar Lake) are significant pathways for site contaminants. Finally, and most importantly, no evidence of contamination associated with Electro-Coatings has been identified in the city’s East Well Field.

In conclusion, no current exposure pathway has been identified.

Future Exposure Pathways: Future exposure to site contaminants are possible, though unlikely. As with current conditions, surface water, sediment, soils, air, and food are not considered to be significant exposure pathways. Potential exposure to contaminated groundwater is the only significant future pathway of concern which has been identified.

Currently the Hawkeye Rubber production well PW-1 is containing most of the site contaminants. The Hawkeye Rubber well as such has functioned much like a groundwater recovery well designed for groundwater remediation.

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The major concern regarding future exposure is the contaminant plume potentially reaching the East Well Field, particularly if operation of the Hawkeye Rubber well PW-1 is ceased. Some residual soil contamination under the Electro-Coatings plant is known to exist which can continue to act a source of groundwater contamination; although lower levels of contamination are anticipated than in the past. If pumping from the Hawkeye Rubber well was to cease or be significantly reduced, contamination in the alluvial aquifer would likely not be drawn into the bedrock aquifer. Groundwater contaminants would likely move off-site in the alluvial aquifer instead of being drawn into PW-1. Should this happen migration groundwater in the alluvial aquifer would be expected to be to the south and west with discharge to Cedar Lake or the Cedar River. However, information does not exist to rule out the possibility that the city’s East Well Field could draw in contaminated groundwater from the site. Future exposure scenarios will assess this possibility.

Two future exposure scenarios have been evaluated involving domestic use of groundwater from the Cedar Rapids municipal water supply as follows:

SCENARIO 1 - Exposure to Impacted Groundwater from One City Well. This scenario assumes the entire contaminant plume associated with Electro-Coatings will be drawn into one city well and people will use water directly from this well for normal residential uses. Raw water from all 46 city wells are mixed at the treatment plant prior to consumption. Exposure to water from a single well does not occur. Therefore, this exposure scenario will be evaluated for demonstrative purposes only. The population potentially exposed under this scenario is the entire population served by the Cedar Rapids Public Water Supply (about 110,000).

SCENARIO 2 - Exposure to Impacted Groundwater from the Entire Cedar Rapids Public Water Supply. This scenario assumes the entire contaminant plume associated with Electro-Coatings will be drawn into the Cedar Rapids municipal water supply and exposure to the contaminants will occur from normal residential uses. The population potentially exposed under this scenario is the entire population served by the Cedar Rapids Public Water Supply (about 110,000).

There are no local ordinances which prohibit development of private water supplies. However, the vicinity of the Electro-Coatings site is zoned industrial and residences are not permitted. Therefore, the potential does not exist for the site to impact any private, domestic well. Future industrial use of contaminated groundwater is very possible. Industrial use for cooling purposes already exists by Hawkeye Rubber. Domestic-type uses within an industry (i.e., drinking water and showering) are also possible, though currently do not exist and are not considered likely given the availability of municipal water. An additional future groundwater exposure scenario will be evaluated involving industrial workers as follows:

SCENARIO 3 - Exposure to Impacted Groundwater by Industrial Workers. It will be assumed that the Hawkeye Rubber Production Well PW-1, or similar well by another industry, could provide water for all uses by an industry, including drinking water and showering. Higher contaminant levels were found in monitoring well #MW-9. However, if water was withdrawn from MW-9 (or other similar well in the immediate vicinity of MW-9) it would also draw in less contaminated water unless the withdrawal rate was very small. A small withdrawal rate would be of little value to an industry given the availability of the municipal water supply. It is believed that the current PW-1 well draws in most if not all of the contaminant plume and this scenario represents the reasonable maximum exposure (RME) expected to occur. The RME is the highest exposure that is reasonably expected to occur at a site.

There are three routes of exposure to contaminants from groundwater: 1) direct ingestion of drinking water, 2) inhalation of volatile contaminants, and 3) dermal contact. Contaminant exposure via ingestion of drinking water is relatively straightforward. Exposure via inhalation of volatilized contaminants in groundwater will be a significant factor for the volatile organic compounds (VOCs) only. Metals have very low volatility and will not be evaluated for exposure via inhalation. Exposure by inhalation can occur for a number of residential activities, especially those using hot water such as cooking, laundering, cleaning, and bathing/showering. Showering represents the largest potential for exposure from inhalation due to the relatively confined space, large volumes of water used, aerating factor, and frequency. Showering alone represents the vast majority of the potential

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exposure by inhalation in a residential setting and will thus be used solely to estimate intake of contaminants by inhalation for both residual use scenarios. It is also conceivable that showering would be a regular activity of industrial workers. Showering will also be assumed to be the primary activity in an industrial setting which would result in exposure to contaminants by inhalation. Dermal contact to water contaminants will also occur from residential and industrial activities (especially bathing/showering) but the level of exposure is assumed to be insignificant compared to that by drinking and inhalation.

33 Quantification of ExposureFor a quantitative risk characterization, estimates of exposure levels for each contaminant are required. As discussed in Section 3.2, exposure of contaminants from groundwater will be evaluated for direct ingestion of drinking water and inhalation of volatiles. In either case, exposure levels are based on groundwater contaminant concentrations.

For Scenarios 1 and 2 involving residential use of water from the Cedar Rapids public water supply, contaminant levels in groundwater are estimated since no actual contamination has been observed. Contaminant levels have been estimated assuming the entire Electro-Coatings’ contaminant plume in drawn into the closest city well without attenuation (e.g., adsorption, volatilization, or biological degradation). Contaminant levels are estimated based on dilution as follows:

CW = CP x FP / FC

Where:CW = Concentration of contaminant in water (mg/1)CP = Concentration of contaminant in plume (mg/1)FP = Plume flow rate (gal/day)FC = Flow rate (gal/day) of one city well (Scenario 1) or the entire public Water Supply

(Scenario 2)

The contaminant plume flow rate (FP) can be calculated using an adaptation of the basic Darcy groundwater equation as follows:

FP = HC x ST x PW x HG x CF

Where: HC = Hydraulic conductivity (cm/sec)ST = Saturated thickness of aquifer (ft)PW = Plume Width (ft)HG = Hydraulic gradient (ft/ft)CF = Conversion Factor = 21,200 (gal/day/ft2)/(cm/sec)

Based on data from the April 1992 Remedial Investigation from Figures 4, 7, and 11 and Table 8 for values of ST, HG, PW, and HC, respectively, a plume flow rate has been calculated as follows:

HC = 0.017 cm/sec ST = 7 ft PW = 165 ft HG = 2 ft/350 ft

FP = 0.017 cm/sec x 7 ft x 165 ft. x 2 ft/350 ft x 21,200 (gal/day/ft2)/(cm/sec)FP = 2.400 gal/dav

The values of ST, PW, and HG are believed to be fairly accurate. The hydraulic conductivity value is considered to be the least accurate. A hydraulic conductivity of 0.017 cm/sec represents a highly permeable formation and could well be greater than what actually exists. Therefore, the estimated plume flow rate is probably on the high side.

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The closest well in the East Well field (No. 6) has a rated capacity of one million gallons a day (FC, = 1,000,000 gal/day). The total daily water production by the Cedar Rapids water plant averages about 28 million gallons per day (FQ = 28,000,000 gal/day). Table 1 shows estimated levels of the contaminants of concern in one city well and the entire city water supply based on the dilution calculation using the highest contaminant levels found in MW-9 to represent the concentration in the contaminant plume (CP).

Contaminant concentrations for Scenario 3 are also shown in Table 1. Concentration for Scenario 3 are based on actual and estimated contaminant concentrations in the Hawkeye Rubber production well PW-1. The 2.8 mg/1 of chromium was the highest concentration found in PW-1 during the Remedial Investigation. This particular sample was collected on March 26, 1991; however, none of the other contaminants of concern were analyzed from the sample. Volatile organic compounds (VOCs) were analyzed in two samples collected from PW-1 (May 8 and September 3, 1991). Relatively low levels of VOCs were found in these samples. Cadmium was analyzed twice in samples from PW-1 and was not detected in either. During the RI samples from PW-1 were not analyzed for Nickel. As a worst-case assessment, contaminant levels in PW-1 (except for chromium) have been estimated to equal the ratio of chromium in PW-1 on 3/26/91 to chromium in MW-9 on 5/8/91 when the highest level of other contaminants were found (2.5/14 = 0.18) times the highest concentration of the other contaminants found in MW-9.

Table 1POTENTIAL CONTAMINANT CONCENTRATIONS IN DRINKING WATER

Contaminant MCL (me/1)Max. Cone. MW-9 (me/I)

SCENARIO 1: Max. Cone. CW-6 (me/1)

SCENARIO 2: Max. Cone. PWS (me/1)

SCENARIO 3: Max. Cone. PW-1 (me/1)

Chromium (VI) 0.1 25 0.060 0.002 2.5*

Cadmium 0.005 0.016 0.00004 0.000001 0.003

Nickel 0.1 0.199 0.0005 0.00002 0.04

1,1-DCE 0.007 0.033 0.00008 0.000003 0.006

C1,2-DCE 0.07 0.560 0.001 0.00005 0.01

1,1,1-TCA 0.2 0.160 0.0004 0.00001 0.03

TCE 0.005 0.890 0.002 0.00008 0.16

Where: MCL = Federal drinking water Maximum Contaminant LevelMW-9 = Monitoring Well #9 (the highest concentration of all contaminants of concern were

found in this well)CW-6 = City Well #6PWS = Cedar Rapids’ entire Public Water Supply PW-1 = Hawkeye Rubber Production Well #1* - Represents the highest concentration of hexavalent chromium found in PW-1 during the

Remedial Investigation. Note: all other contaminant concentrations for Scenario 3 are calculated based on dilution of the highest levels measured in MW-9.

Example Calculation: Scenarios 1 and 2: Concentration in water, CW = CP x FP / FCCP = Max. concentration of Nickel in MW-9 = 0.199 mg/1 CW, = 0.199 mg/1 x 2,400 gal/day / 1,000,000 gal/day = 0.0005 mg/1 CW2 = 0.199 mg/1 x 2,400 gal/day / 28,000,(XX) gal/day = 0.00002 mg/1 Scenario 3: CW3 = 0.199 mg/1 x 0.18 = 0.04 mg/1

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Estimation of intake via drinking water has been made using the following equation:

Intake (mg/kg-day) = (CW xIRx EF x ED)/(BW x AT)

Where: CW = Chemical concentration in water (mg/1) (from Table 1)IR = Ingestion rate; assume = 2 1/day (Scenarios 1 and 2) (Source: Dec. 1989, Risk

Assessment Guidance (RAGS)), 1.3 1/day (Scenario 3; assumes one third of daily water consumption away from the workplace)

EF = Exposure frequency; assume = 365 days/yr. (Scenarios 1, 2, and 3-subchronic) and 250 days/yr. (Scenario 3-chronic)

ED = Exposure duration; assume = 1 yr. (subchronic); 70 yr. (Scenarios 1 and 2, chronic);and 30 years (Scenario 3, chronic)

BW = Body weight; assume adult = 70 kg (Source: RAGS)AT = Averaging time (period over which exposure is averaged in days) = 70 yr. x 365 days/yr.

= 25,550 days (chronic), 1 yr. x 365 days/yr. = 365 days (subchronic)

Table 2 summarizes contaminant intake via drinking water under the three future exposure scenarios. Normally a short-term and long-term exposure are evaluated in the risk assessment process. However, given the low concentrations of contaminants in one city well with worst-case assumptions and the greater sensitivity from longterm exposure, short-term exposure assessments have not been made for Scenarios 1 and 2 involving the public water supply.

Table 2ESTIMATED INTAKE VIA DRINKING WATER

SCENARIO 1: SCENARIO 2: SCENARIO 3: SCENARIO 3:

Contaminant

ChronicIntake(mg/kg-dav)

ChronicIntake(mg/kg-day)

Sub-chronicIntake(mg/kg-day)

ChronicIntake(mg/kg-dav)

Chromium (VI) 0.002 0.00006 0.05 0.01

Cadmium 0.000001 0.00000003 0.00006 0.00002

Nickel 0.00001 0.0000006 0.0007 0.0002

1,1-DCE 0.000002 0.00000009 0.0001 0.00003

C1.2-DCE 0.00003 0.000001 0.0002 0.00005

1,1,1-TCA 0.00001 0.0000003 0.0006 0.0002

TCE 0.00006 0.000002 0.003 0.0009

Example Calculation: Scenario 3: Chronic Intake of TCE

CW = 0.16 mg/1 (Table 1)

Intake = (CW x IR x EF x ED) / (BW x AT)= (0.16 mg/1 x 1.3 1/day x 250 days/yr x 30 yr) / (70 kg x 25,550 days) = 0.0009 mg/kg-day

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Estimation of intake via inhalation while showering will be made using the following equation:

Intake (mg/kg-day) = (CA x IR x ET x EF x ED)/(BW x AT)

Where: CA = Contaminant concentration in air (mg/cu.m); see computation belowIR = Inhalation rate; assume = 0.6 cu.m/hr. (Source: Dec. 1989, EPA Risk Assessment

Guidance (RAGS))ET = Exposure time; assume = 0.2 hr./day (Source: RAGS)EF = Exposure frequency, assume = 365 days/yr. (Scenarios 1, 2, and 3-subchronic) and

250 days/yr. (Scenario 3-chronic)ED = Exposure duration; assume = 70 yr.(Scenarios 1 and 2, chronic); 30 yr. (Scenario 3, chronic); 1 yr. (Scenario 3, subchronic)BW = Body weight, assume = 70 kgAT = Averaging time (period over which exposure is averaged in days); 70 yr. x 365 days/yr.

= 25,550 days (chronic) and 1 yr. x 365 day/yr. = 365 days (subchronic)

CA assumptions:CA = CWxVWxAF/VR

Where: CW = Contaminant concentration in water from Table 1 (mg/1)VW = Volume of water used per shower, assume = 120 1AF = Averaging factor, assume = 0.5 (no concentration at start and full at end of shower) VR = Volume of room, assume = 12 cu.m (bathroom)

Table 3 presents estimated inhalation intakes based on the above.

Table 3ESTIMATED INTAKE V IA INHALATION

Contaminant

SCENARIO 1: ChronicIntake(mg/kg-day)

SCENARIO 2:ChronicIntake(mg/kg-day)

SCENARIO 3: Sub-chronic Intake (mg/kg-day)

SCENARIO 3: ChronicIntake(mg/kg-day)

Chromium (VI) NA NA NA NA

Cadmium NA NA NA NA

Nickel NA NA NA NA

1,1-DCE 0.0000007 0.00000003 0.00005 0.00002

C1.2-DCE 0.000009 0.0000004 0.00009 0.00003

1,1,1-TCA 0.000003 0.00000009 0.0003 0.00008

TCE 0.00004 0.0000007 0.001 0.0004

Example Calculation: Scenario 3: Chronic Intake of TCE

CA = CWxVWxAF/VR = 0.16 mg/1 x 120 1 x 0.5 / 12 m3 = 0.8 mg/m3

Intake = (CA x IR x ET x EF x ED) / (BW x AT)= (0.8 mg/m3 x 0.6 m3/hr x 0.2 hr/day x 250 days/yr x 30 yr) / (70 kg x 25,550 days) = 0.0004 mg/kg-day

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3.4 Exposure UncertaintiesIn general, the quantified exposures represent conservative estimates of conditions. Estimated potential impacts to the city wells (Scenarios 1 and 2) are based on ultra-conservative assumptions. Groundwater modeling reported in the April 1992 Remedial Investigation suggested that the city wells are not threatened. It is quite possible that site contaminants would not be drawn to the city wells even if pumping from PW-1 was to cease. It is not known whether or not the city wells would even draw in groundwater from as far as the Electro-Coatings site. Without pumping from PW-1, groundwater may flow to the southwest and discharge to Cedar Lake or Cedar River.

Another conservative assumption used for Scenarios 1 and 2 is the exposure frequency (EF). An EF = 70 years has been used which assumes an individual would be exposed to the same level of contamination in the municipal water supply for 70 years. The EPA typically uses an EF = 30 years for exposure to carcinogens, the 90th percentile of the duration at one residence. However, an EF = 70 years was conservatively used since it is likely that a change of residence would be within the same community.

The exposures quantified for Scenario 3 are more realistic in terms of potential contaminant concentrations, although actual exposure is not likely given the availability of city water. Scenario 3 is considered to be the reasonable maximum exposure scenario. The currently impacted Hawkeye Rubber well is used only for cooling water. Any new industrial use would likely be located at a greater distance from Electro-Coatings than Hawkeye Rubber, and as such would likely draw in lower levels of contaminants. Also a new industrial use would likely draw in significant contaminants only if the Hawkeye Rubber well PW-1 was no longer in operation.

With the recent action to eliminate an ongoing release of contaminants, contaminant levels are anticipated to decrease with time. Therefore, the levels of contaminants used to quantify exposure should overestimate actual future levels.

As discussed in Section 3.2, exposures to impacted groundwater can occur by means other than drinking water and inhalation during showering which have been quantified. Other incidental exposures may include inhalation during activities other than showering and dermal contact. However, these other potential exposures from groundwater would be minor in comparison to the quantified exposures

Potential exposures to contaminated media other than groundwater have not been evaluated in this risk assessment. Significant routes of exposure from other media have not been identified. However, characterization of contamination in other media (e.g., soils) has not been as intensive as it has been for groundwater. It is possible that significant exposure could result from other contaminated media (e.g., soils), although such a situation is considered highly unlikely. The area immediately surrounding the Electro-Coatings plant is paved precluding exposure to shallow soils. Also, the release of chromic acid was from concrete tanks below grade.

Overall, the likelihood of underestimating potential exposures to site contaminants is extremely unlikely. Again, it must be emphasized that there is little current exposure to contaminants (incidental exposure to Hawkeye Rubber cooling water) nor is significant exposure anticipated.

4.0 TOXICITY ASSESSMENTThe purpose of toxicity assessment is to weigh available evidence regarding the potential for the contaminants of concern to cause adverse effects in exposed populations. The toxicity assessment will provide an estimate of the relationship between the magnitude of exposure to a contaminant and the increased likelihood or severity of adverse effects.

Information on toxicity of chemicals is available from various sources. The U.S Environmental Protection Agency maintains a health risk assessment database called the Integrated Risk Information System (IRIS) and also publishes quarterly Health Effects Assessment Summary Tables (HEAST). These information sources have been utilized in this Baseline Risk Assessment. The December 1992 IRIS and March 1992 HEAST additions were utilized.

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4.1 Toxicity Information for Non-Carcinogenic EffectsA reference dose (RfD) is the toxicity value that is used to evaluate non-carcinogenic effects. A chronic RfD is defined as an estimate (with uncertainty of perhaps an order of magnitude or greater) of a daily exposure level for the human population, including sensitive subsystems, that is likely to be without an appreciable risk of deleterious effects during a lifetime. A chronic RfD is designed to be protective for long-term exposure to a compound. Long-term exposure will be assumed to be between 7 years ( approximately 10% of a human lifetime) and a lifetime. A subchronic RfD is used to characterize noncarcinogenic effects associated with shorter exposures of 2 weeks to 7 years. Table 6 summarizes toxicity values for potential non-carcinogenic effects and the critical effects from exposure to each compound. Table 4 also shows the confidence levels and uncertainty factors associated with the reference doses. The confidence level is an overall assessment of the quality of the study(ies) and database upon which the reference is based. The Uncertainty Factor is a correction made to actual data to take into account extrapolation from laboratory animals to humans, protection for sensitive humans, and deficiencies in the studies used to determine the reference dose.

Table 4TOXICITY VALUES FOR POTENTIAL NON-CARCINOGENIC EFFECTS

Subchronic Confi-R1D Chronic RfD dence Critical Source Uncertainty

Chemical (mg/kg-day) (mg/kg-day) Level Effect of RfD Factor

Chromium (VI) 2E-2 5E-3 Low None observed IRIS/HEAST 100/500

Cadmium - 5E-4 High Significantproteinuria

IRIS 10

Nickel 2E-2 2E-2 Medium Decreased body and organ weights

IRIS/HEAST 300

1,1-DCE 9E-3 9E-3 Medium Liver lesions IRIS/HEAST 1000

C1,2-DCE IE-1 IE-2—

Decreased hematocrit and hemoglobin

HEAST 300/3000

1,1,1-TCA 9E-1 9E-2 - Liver toxicity HEAST 100/1000

TCE pending pending — — IRIS —

42 Toxicity Information for Carcinogenic EffectsRisk evaluation of carcinogenic effects is based on a "nonthreshold" assumption. That is, it is assumed that there is essentially no level to such a chemical that does not pose a finite risk, however small, of causing cancer. Therefore, in evaluating cancer risks, there is no threshold level below which no risk is assigned. The EPA has evaluated available data to determine the likelihood that a chemical is a human carcinogen. Table 5 summarizes EPA’s classification of carcinogens based on weight-of-evidence.

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Table 5EPA WEIGHT-OF-EVIDENCE CLASSIFICATION SYSTEM FOR CARCINOGENICITY

Group Description

A Human carcinogen

B1 Probable human carcinogen with limited human data available

B2 Probable human carcinogen with sufficient evidence in animals but inadequate orno evidence in humans

C Possible human carcinogen

D Not classified as to human carcinogenicity

E Evidence of non-carcinogenicity for humans

The EPA has calculated toxicity values, called slope factors, for potential carcinogens in classes A, Bl, and B2 and some class C. A slope factor is an estimate of the probability of response per unit intake of a chemical over a lifetime. The slope factor is used to estimate an upper-bound probability of an individual developing cancer as a result of a lifetime exposure to a particular level of a potential carcinogen. Table 6 summarizes toxicity values for potential carcinogenic effects for both oral and inhalation routes of exposure to a contaminant. Also shown in Table 6 for TCE is the drinking water unit risk factor which when multiplied by the concentration in drinking water (mg/1) gives the cancer risk estimate. The drinking water unit risk factor for TCE was derived from the December 1992, DRINKING WATER REGULATIONS AND HEALTH ADVISORIES by the Office of Water U.S. Environmental Protection Agency. TCE is classified as a B2 carcinogen in that document.

Table 6TOXICITY VALUES FOR POTENTIAL CARCINOGENIC EFFECTS

Slope FactorWeight of Evidence

Contaminant (mg/kg/dav)'1 Classification

Chromium (VI) None (oral) A (Inhal.)

Cadmium None (oral) Bl (Inhal.)

Nickel None D

1,1-DCE 6E-1 (oral) C1.2E+0 (inhal.) C

C1.2-DCE None D

1,1,1-TCA None D

TCE Pending —

Type ofCancer

InformationSource

Drinking Water Unit Risk (mg/1)'1

- IRIS/HEAST -

- IRIS/HEAST -

- IRIS -

Kidney Adenocarcinoma

IRIS/HEASTIRIS/HEAST

—

- IRIS --

- IRIS -

__ IRIS 3.3E-4

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43 Uncertainties related to Toxicity InformationThere are varying degrees of uncertainty associated with the toxicity values presented in this section. The confidence level and uncertainty factors shown in Table 4 illustrate the relative uncertainties regarding the reference doses shown. The confidence levels are based on the quality of the study used to determine the RfD and the existence and quality of other studies which form the database available for each chemical. The uncertainty factors are adjustments made to toxicity values from actual studies to: allow for uncertainties such as conversion of animal data to humans; provide protection for sensitive human subpopulations; and compensate for inadequacies in studies. In general, high uncertainty factors and low confidence levels indicate the toxicity value might change as additional data becomes available.

The Weight-of-Evidence classification for carcinogens indicates the likelihood that a chemical causes cancer in humans. Lower classifications correspond to less certainty that a compound is a human carcinogen. Slope Factors for carcinogens are often derived using short-term dose-response information observed in animals at high doses to predict long-term effects in humans when exposed to low doses. As stated previously, the Slope Factors represent a plausible upper-bound limit of cancer risk with actual risk likely being less.

5.0 RISK CHARACTERIZATION

5.1 Current Land-Use ConditionsNo significant current exposure to site contaminants has been identified.

52 Future Land Use ConditionsNo significant change in land use is anticipated. Levels of contaminants in the environment are expected to decline in the future because of measures taken by Electro-Coatings to prevent further releases including the recent removal of chromium-contaminated soil. The degradation properties of VOCs in soils and the relatively fast movement of groundwater will likely result in future declines in contaminant levels. Future conditions are conservatively assumed to be the same as current conditions.

Table 7 shows estimated cancer risks based on the three future exposure scenarios using the chronic daily intakes shown in Tables 2 and 3 and the toxicity values shown in Table 6. Cancer risk has been calculated by multiplying the chronic daily intake by the Slope Factor. Risk is expressed as an upper-bound estimate of the additional cancers which could result from lifetime exposure to the contaminant. For example, a cancer risk of 5 x 10'5 (or 5/100,000) means that the cancer risk to a person exposed to the site contaminants is increased by 5/100,000 over background. The National Contingency Plan (NCP), rules for implementing the Superfund program, identifies an acceptable risk range of excess cumulative carcinogenic risk for a site to be 1/10,000 to 1/1,000,000. In other words, sites increasing the carcinogenic risk for a reasonable maximum exposure by 1/10,000 over background are generally considered appropriate for remedial action. Remedial risk may also be required based on noncarcinogenic risk to humans or because of environmental threats, or ecological risks.

Table 8 summarizes non-carcinogenic risks from chronic exposure to contaminants. Table 9 summarizes noncarcinogenic risks from subchronic exposure to contaminants (Scenario 3 only). In these tables a Hazard Quotient represents the ratio of an exposure level to a single substance over a specified time period (e.g., subchronic) to a Reference Dose for a similar exposure period. A Hazard Quotient greater than one indicates potential for concern from non-carcinogenic health effects. A Hazard Quotient does not represent a probability of an adverse effect occurring. The Hazard Index is the sum of the Hazard Quotients for each exposure pathway and/or all pathways. A Hazard Index greater than one may also be of concern with respect to non-cancer health effects. As with a Hazard Quotient, a Hazard Index does not represent a probability of an adverse effect occurring.

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Table 7CANCER RISK ESTIMATES

Contaminant

Chronic DailyIntake(mg/kg-day)

WaterSlope Factor Concentration(mg/ks-davV1 (mg/1)

Drinking Water Unit Risk (mg/I)'1

Chemical-Specific Risk Oral Inhalation

SCENARIO 1: ONE CITY WELL

1,1-DCE 7E-7 (inhal.) 1.2E + 0 (inhal.) — — — 8 x 10'7

2E-6 (oral) 6.0E-1 (oral) 1 x 10^ ...

TCE ~ 0.002 33E-4 7 x 10'7 ...TOTAL CANCER RISK SCENARIO 1 = 3 X lO'6

SCENARIO 2: PUBLIC WATER SUPPLY

1,1-DCE 3E-8 (inhal.) 1.2E + 0 (inhal.) — — ... 4x 10-8

9E-8 (oral) 6E-1 (oral) 5x10-®

TCE — 0.00008 3.3E-4 3x 10-8—

TOTAL CANCER RISK SCENARIO 2 = 1 X 10 7

SCENARIO 3: INDUSTRIAL USE

1,1-DCE 2E-5 (inhal.) 1.2E+0 (inhal.) — — ... 2 x 10'5

3E-5 (oral) 6E-1 (oral) 2 x 10'5

TCE — 0.16 3.3E-4 5 x 10 s ...TOTAL CANCER RISK SCENARIO 3 = 9 X 10^

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Table 8CHRONIC HAZARD INDEX ESTIMATES

Chronic Daily Intake Chronic(mg/kg-day) Reference Dose Hazard Quotient

Contaminant Oral Inhalation (mg/kg-day) Oral Inhalation Total

SCENARIO 1: ONE CITY WELL

Chromium (VI) 2E-3 NA 5E-3 0.40 NA 0.40

Cadmium IE-6 NA 5E-4 0.00 NA 0.00

Nickel IE-5 NA 2E-2 0.00 NA 0.00

1,1-DCE 2E-6 7E-7 9E-3 0.00 0.00 0.00

C1.2-DCE 3E-5 9E-6 IE-2 0.00 0.00 0.00

1,1,1-TCA IE-5 3E-6 9E-2 0.00 0.00 0.00

TCE 6E-5 2E-5 (pending) — — —

TOTAL CHRONIC HAZARD INDEX: SCENARIO 1 = 04 M 0.4

SCENARIO 2: PUBLIC WATER SUPPLY


Cadmium 3E-8 NA 5E-4 0.00 NA 0.00

Nickel 6E-7 NA 2E-2 0.00 NA 0.00

1,1-DCE 9E-8 3E-8 9E-3 0.00 0.00 0.00

C1.2-DCE IE-6 4E-7 IE-2 0.00 0.00 0.00

1,1,1-TCA 3E-7 9E-8 9E-2 0.00 0.00 0.00


TOTAL CHRONIC HAZARD INDEX: SCENARIO 2 = 0.01 0.00 0.01

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Table 8 (CONT.)CHRONIC HAZARD INDEX ESTIMATES

Contaminant

Chronic Daily Intake (mg/kg-day)

Oral Inhalation

ChronicReference Dose (mg/kg-dav) Oral

Hazard Quotient Inhalation Total


Chromium (VI) IE-2 NA 5E-3 2.0 NA 2.0

Cadmium 2E-5 NA 5E-4 0.04 NA 0.04

Nickel 2E-4 NA 2E-2 0.01 NA 0.01

1,1-DCE 3E-5 2E-5 9E-3 0.00 0.00 0.00

C1.2-DCE 5E-5 3E-5 IE-2 0.00 0.00 0.00

1,1,1-TCA 2E-4 8E-5 9E-2 0.00 0.00 0.00


TOTAL CHRONIC HAZARD INDEX; SCENARIO 3 = 1A 0.00 2J.

Table 9SUBCHRONIC HAZARD INDEX ESTIMATES


Contaminant

Subchronic Daily Intake (mg/kg-day) Oral Inhalation

SubchronicReference Dose (mg/kg-day) Oral

Hazard Quotient Inhalation Total


Cadmium 6E-5 NA 5E-4 (chronic RID) 0.1 NA 0.1

Nickel 7E-4 NA 2E-2 0.04 NA 0.04

1,1-DCE IE-4 5E-5 9E-3 0.01 0.01 0.02

C1.2-DCE 2E-4 9E-5 IE-1 0.00 0.00 0.00

1,1,1-TCA 6E-4 3E-4 9E-1 0.00 0.00 0.00

TCE 3E-3 IE-3 (pending) — — —

TOTAL SUBCHRONIC HAZARD INDEX: SCENARIO 3 = 2J_ M M

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53 UncertaintiesThe assessment of risks presented are based upon a considerable number of assumptions regarding both exposure and toxicity. Exposure to contaminated groundwater is based upon what is believed to be worst-case assumptions with respect to potential impact on the city wells in Scenarios 1 and 2. It is not even known for sure if it is physically possible for the city wells to draw in the site contaminants. The contaminant levels used in Scenario 3 are plausible. However, it is unlikely that contaminated water would be used for drinking water or showering at an industrial facility. All three future exposure scenarios have been based upon current contaminant levels despite likely declines in contaminant levels over time. Exposure via inhalation is based upon several assumptions especially concentrations in air. Due to lack of data, dermal exposure was not calculated separately but was assumed to be incidental to other routes of exposure. There simply is not sufficient data to support a significant exposure to site contaminants via soil or air. Overall, exposures used in Scenarios 1 and 2 are vastly overestimated and exposures used in Scenario 3 are slightly overestimated.

Uncertainties in toxicity values result in largely from estimating impacts to humans based on animal studies. Uncertainty factors ranging from 10 to 3000 are built into the reference dose levels to account for variations on human sensitivity, animal to human extrapolation, and deficiencies in the studies used to determine reference doses. Slope factors used to estimate cancer risks are based on animal studies in which relatively high exposure to chemicals over a short period (e.g. two years) are used to predict the effects in humans from long-term exposure to low doses. Also the methodology used by EPA to calculate slope factors uses conservative assumptions to derive plausible upper-bound risk estimates; actual risks likely being lower.

In addition to the uncertainties associated with exposure and toxicity assumptions, uncertainties exist regarding potential synergistic and antagonistic interactions with other substances.

5.4 Summary Discussion of Risk CharacterizationEstimated excess cancer risks do not exceed the upper end of the acceptable range (1 x 10'4) for any of the three exposure scenarios. The RME, Scenario 3, does come close with an estimated excess cancer risk of 9 x 10'5. Estimated excess cancer risk for Scenario 1 in within the acceptable range but slightly exceeds the lower end of the acceptable range (1 x 10"*). About three quarters of the estimated excess cancer risk for each scenario is from exposure to 1,1-dichloroethene (1,1-DCE) which is only a possible human carcinogen. The estimated concentrations of 1,1,-DCE in water are below the MCL in all three scenarios and below normal analytical detection levels in Scenarios 1 and 2. Therefore, 1,1-DCE is not considered to pose a significant cancer risk. The cancer risk associated with trichloroethene (TCE) appears to be significant for Scenario 3 only, although still within the acceptable risk range. The concentration of TCE in water in Scenario 3 does exceed the MCI by a factor of 30.

The hazard indices are less than one for Scenarios 1 and 2 which indicates no concern regarding exposure to non-carcinogens. Both the subchronic and chronic hazard indices for Scenario 3 exceed one which indicates a concern from short-term and long-term exposure to contaminants. Chromium (VI) is the only contaminant of concern to have a hazard quotient greater than one and represents the sole concern with respect to non- carcinogenic risks.

In conclusion, the Cedar Rapids’ water supply is not threatened by contamination from the Electro-Coatings site. The contamination from the Electro-Coatings site does not have the potential to significantly impact even one city well (Scenario 1) much less the entire city water supply (Scenario 2). The RME, Exposure to site contaminants by an industrial worker (Scenario 3), would result in unacceptable risks. Non-carcinogenic effects from exposure to chromium (VI) would be the primary concern. Exposure to TCE in drinking water would also be well in excess of the MCL and pose a marginal cancer risk.

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6.0 SUMMARY

6.1 Chemicals of Potential ConcernChemicals of potential concern fall into two general categories; metals associated with plating operations and volatile organic compounds used for solvents. Specific chemicals of concern are as follows:

Metals:Chromium (VI)CadmiumNickel

Volatile Organic Compounds (VOCs):1.1- Dichloroethene (1,1-DCE)Cis 1,2-Dichloroethene (C1.2-DCE)1.1.1- Trichloroethane (1,1,1-TCA)Trichloroethene (TCE)

Tetrachloroethene or perchloroethene (PCE) was also found in significant concentrations in groundwater but was not attributed to Electro-Coatings. The PCE contamination has been attributed to Hawkeye Rubber Company who will be conducting their own investigation.

62 Exposure AssessmentNo significant current exposure to site contaminants was identified. Three future exposure scenarios have been evaluated. They are:

1) Domestic use (drinking and showering) of water from a single city well which is assumed to draw in all site contaminants;

2) Domestic use (drinking and showering) of the entire city water supply which has assumed to draw in all site contaminants; and

3) Industrial use (drinking and showering) from the Hawkeye Rubber Production Well #PW-1.

Scenario 3 is considered to be the Reasonable Maximum Exposure scenario which is the basis for determining is remedial action is warranted. Scenarios 1 and 2 were evaluated to demonstrate the maximum potential impact on the Cedar Rapids’ municipal water supply assuming all the site contaminants are drawn into the municipal water supply (an extremely unlikely situation).

Groundwater exposures for the first two scenarios have been based on a calculated rate of contaminant movement (mass of contaminant per day) emanating from Electro-Coatings site. This total daily contaminant mass has been conservatively assumed to be drawn into one city well. The highest concentration of contaminants found (or estimated based on maximum monitoring well concentrations) during the RI in Hawkeye Rubber Production Well PW-1 have been used for Scenario 3 (industrial use). These concentrations are shown in Table 10 along with regulatory levels. PCE has been included to Table 10 although was not evaluated in detail in the risk assessment.

Table 10OBSERVED AND REGULATORY GROUNDWATER CONCENTRATIONS

ContaminantMaximum RI Cone, (mg/1)

Max. Cone. PW-1 tmn/11

MCL(mg/1)

IGALlffig/11

Chromium (VI) 25 25* 0.1 0.1

Cadmium 0.016 0.003 0.005 0.005

Nickel 0.199 0.04 0.1 0.1

1,1-DCE 0.033 0.006 0.007 0.007

C1,2-DCE 0.560 0.01 0.07 0.07

1,1,1-TCA 0.160 0.03 0.2 0.2

TCE 0.890 0.16 0.005 0.003

PCE 15.4 0.253 0.005 0.7

* Actual maximum concentration found in PW-1 during RI; concentration of other contaminants based on dilution calculation.

NOTE: values shown in italics exceed the MCL and IGAL.

63 Toxicity AssessmentToxicity of the chemicals of concern was based on information from the May 1,1993, update of EPA’s Integrated Risk Information System (IRIS), and the March 1992 Health Effects Assessment Summary Tables (HEAST).1,1-Dichloroethene (1,1-DCE) and trichloroethene (TCE) are classified as C Possible and B2 Probable Human Carcinogens, respectively. Slope factors for cancer risk assessments were available for only 1,1-DCE. Toxicity information on TCE is pending from IRIS and/or HEAST. A drinking water unit risk factor for estimating cancer risk from exposure to TCE in drinking water was adapted from the December 1992 DRINKING WATER REGULATIONS AND HEALTH ADVISORIES by the U.S. Environmental Protection Agency Office of Water. Reference Doses were obtained from IRIS and/or HEAST for all contaminants of concern except TCE.

6.4 Risk CharacterizationTable 11 below summarizes the assessment of risks. Unacceptable risks, a hazard index greater than 1, have been identified for Scenario 3 only. The excess cancer risks for Scenario 1 and 3 do exceed the more desirable goal for cancer risk of 1 x 10"6. However, Scenario 1 is for exposure from only one city well which does not occur and is based on the ultra-conservative assumption that all site contaminants will be drawn into that one well. This risk assessment clearly demonstrates that the Cedar Rapids public water supply is not threatened by contaminants from the Electro-Coatings site.

As stated previously, significant PCE contamination of groundwater exists at the site, although it is not attributed to Electro-Coatings and has not been evaluated in detail in this risk assessment. A simple dilution calculation, similar to the method used to estimate potential exposure for Scenarios 1 and 2 and the maximum concentration of PCE found during the RI, the maximum amount of PCE would be 0.037 mg/1 in one municipal well and 0.001 mg/1 in the entire municipal water supply. Based on this calculation, the PCE contamination does not appear to have the potential to exceed the drinking water standard of 0.005 mg/1 in the Cedar Rapids’ municipal water supply. Furthermore, recent samples from the two city wells closest the site revealed no PCE contamination with a 0.0005 mg/1 detection limit.

24

Table 11Summary of Assessed Risks

Exposure Scenario Cancer RiskChronic Hazard Index

Subchronic Hazard Index

1) Domestic use of water from one city well

3x KT6 0.4 NA

2) Domestic use of water from entire public water supply

1 x 10'7 0.01 NA

3) Industrial use of water from Hawkeye Production Well #1

9 x 10'5 2.1 2.7

6.5 Ecological AssessmentAn ecological assessment of the Electro-Coatings site was not performed. Previous (before March 1976) discharge of contaminated groundwater to Cedar Lake was discussed in Section 1.2. Based on previous studies of Cedar Lake and limited sampling during the Remedial Investigation, no significant impact to Cedar Lake has been found. Otherwise, site contaminants have been substantially contained by the Hawkeye Rubber cooling water well PW-1 which in turn discharges to the sanitary sewer. Therefore, no significant route of ecological exposure has been identified.

25

Figure 1: LOCATION MAP

26

©

MW—3® MW—4

CEDAR LAKE

Figure 2: CHROMIUM VI IN GROUNDWATER

27

CEDAR LAKE

CEDAR LAKE

Figure 3: TCE AND PCE IN GROUNDWATER

28

I

ATTACHMENT "A”

PRE-1986 ANALYTICAL DATA

29

Hawkeye Rubber Co. Well- #1 (units in mg/1)

Date Cr (Hex) Cr (Tot.

March 1976 11.0 18.0April 1976 6.0 7.9

May 1976 5.0 6.5June 1976 6.0 6.5July 1976 5.5 7.5

August 1976 6.2 7.3September 1976 6.5 7.3

December 1976 10.0 13.4February 1977 14.5 20.4

March 1977 12.5 14.4April 1977 13.0 14.7

May 1977 6.5 7.2June 1977 6.0 7.3July 1977 6.1 8.8


October 1977 5.0 5.8November 1977 5.2 6.8February 1978 -- 10.04

March 1978 9.41 10.6April 1978 7.57 8.92

May 1978 5.37 5.30July 1978 5.74 11.30


October 1978 3.53 6.35November 1978 4.80 9.82December 1978 4.50 9.73January 1979 5.1 10.0

February 1979 7.8 19.0March 1979 -- 33.0April 1979 5.33 9.96

May 1979 4.30 9.96June 1979 3.00 —

July 1979 4.82 9.25August 1979 — 9.26

December 1982 8.20 8.16January 1983 9.00 11.6

March 1983 11.0 11.0

TABULATION TABLE FOR HAWKEYE WELL §2, TEST WELLS #1, #2, #3, #4

DATE LAB HAWKEYE WELL #2

TESTWELL #1

TESTWELL #2

TESTWELL #3

TESTWELL #4

HAWKEYERUBBER

PRESSURE TANK

03-05-76CrT <0.2 Cr+6 <0.1

03-09-76TFT 078~Cr+6 0.5

03-10-76TTI 270

Cr+6 1.25

03-12-76TFT nr~

Cr+6 1.2

03-15-76CrT 1.65 Cr+6 1.0

03-17-76CrT n#65 Cr+6 0.30

04-18-78CrT <0.01 <0.01 TFT 578

Cr+6 5.5

04-20-78SanitationLab

CrT <0.02 Cr+6 0.003

<0.020.003


CrT <0.02 Cr+6 0.005

<0.020.005

05-10-78 City ofCedar Rapids

CrT <0.1 Cr+6 0.00

06^^78 City ofCedar Rapids

CFT <0.1

06-27-78City ofCedar Rapids

CrT <o.05 Cr+6 0.005

<0.050.005


TFT <0.05


TFT o-


CrT <0.005 Cr+6<0.05

<0.005<0.05

08-28-78SanitationLabs

Cr+6 0.003 CrT 0.05

0.004<0.05


Cr+6 0.005 CrT <o.05

0.003<0.05


TFT <0.10 Cr+6 <0.10


CrT <o.02 Cr+6 <0.10


Cr+6 0.009 CrT <0.05

0.006<0.05

11-29-78SanitationLabs

Cr+e'T.0'03

CrT <0.05

005

<0.05


TFT <0.10 Cr+6 <0.10

12^^78City ofCedar Rapids

Cr+b <0.10 CrT 0.10

TR:bsg/AUSM335L05.03

TABULATION TABLE FOR HAWKEYE WELL #2, TEST WELLS #1, #2, #3, 04

DATE LAB HAWKEYE

well nTEST

WELL #1TEST

WELL #2TEST

WELL #3TEST

WELL #4

HAWKEYERUBBER

PRESSURE TANK

12-28-78 SanitationLab


Cr+o <0.1 CrT <0.1


Cr+6 <0.1 CrT <0.1


Tr^6 ~CrT <0.1


Cr+6 <0.1 CrT <0.1


Cr+6 <o.iCrT <0.1


Cr+6 <0.1 CrT


Cr+6 <o.lCrT <0.1


TF6 ~CrI <0.1


CrT o.Ol Cr+6 <0.01

01-21-83 SanitationLabs

Cr+6CrT

Cr+6<o.o05 CrT <0.008

<0.005<0.008 #

01-25-83 StateHygienic Lab

Cr+6<-0.01CrT 0.23

<■0.010.05

03-23-83Sanitation Labs fr/EC

Cr <0.02 <0.02

03-24-83Sanitation Labs fr/EC

Cr <0.02 <0.02

03-24-83StateHygienic Lab^

CrT <0.01 Cr+6<0.05

0.13<0.01

10-10-83StateHygienic Labs

Cr+6<0.05 CrT <0.01

<0.05<0.01

Crr6<0.05 CrT 0.08

<0.050.02

TR:bsg/AUSM335L05»04

APPENDIX "B"

ANALYTICAL DATA FROM THE 1986 SITE INSPECTION

30

LABORATORY ANALYSIS

The results of the chromium samples were received on October 16, 1986. The following tables show the results from the analysis. A copy of the sample results are shown in Appendix A.

Groundwater Laboratory Results

LocationSpecific

Conductivity (u V)

TotalDissolved Solids

Cyanide (mg/1)

Cadmiurn (mg/1)

Chromiurn (mg/1)

Hexavalent Chromium

(mg/1)

Test Well #1 1000 632 < 0.Q1 0.53 0.03 < 0.05

Test Well #2 590 372 < 0.01 0.08 0.06 < 0.05

Test Well #3 350 272 < 0.01 < 0.02 0.10 < 0.05

Test Well #4 560 490 < 0.01 < 0.02 0.07 < 0.05

Test Well #5 1100 680 < 0.01 0.23 1.3 < 0.05

City Wei 1 #1East Field 660 344 < 0.01 < 0.02 < 0.02 < 0.05

Hawkeye Well #1 1000 624 < 0.01 < 0.02 1.3 1.3

Hawkeye Wei 1 #1 Duplicate 1100 636 < 0.01 < 0.02 1.3 1.3

Hawkeye Well #2 560 280 < 0.01 < 0.02 0.67 < 0.05

Hillary Erickson 750 4 50 < 0.01 < 0.02 < 0.02 < 0.05

Field Blank 7.0 < 1 < 0.01 < 0.02 < 0.02 < 0.05

Surface Water Laboratory Re suits

LocationSpecific

Conductivity (u V)

TotalDissolvedSolids

Cyanide(mg/1)

Cadmium (mg/1)

Chromium(mg/1)

Hexavalent Chromiurn

(mg/1)

Cedar Lake - East Edge of

Hawkeye Rubber Company Property

230 132 < 0.01 < 0.02 < 0.02 < 0.05

Cedar Lake - Midpoint of

Hawkeye Rubber Company Property

270 122 < 0.01 < 0.02 < 0.02 < 0.05

- 9 -TSR:rlz/AUSS005J02.01 - .09

Sediment Laboratory Results

Cyanide Cadmiurn ChromiurnLocation (mg/kg) (mg/kg) (mg/kg)

Cedar Lake - East Edge of Hawkeye Rubber Company < 1 < 2 .. -28

PropertyCedar Lake - Midpoint

of Hawkeye Rubber Company < 1 < 2 68Property

ATTACHMENT "C

COMPILATION OF ANALYTICAL DATA FROM THE

REMEDIAL INVESTIGATION

LEGEND

(N) - Analysis conducted by National Environmental Testing, Inc., Cedar Falls, Iowa

(U) - Analysis conducted by the University of Iowa Hygienic Laboratory

(S) - Analysis conducted by San Labs, Cedar Rapids, Iowa

< - indicates that the compound was less than the quantification limit.

— indicates than an analysis was not conducted for that compound,

d - indicates a duplicate sample.

( ) - values in parentheses indicate a field filtered sample.

ELECTRO-COATINGS SITE: GROUNDWATER CONTAMINANT CONCENTRATION (mg/1)

Locatior(Lab)

SampleDate

Cadmium Chromium(total)

Chromium(VI)

Nickel 1,1"Dichloro-ethene

Cis-1,2- Dichloro -ethene

1,1,1- Trichlor -oethane

Tri-chloro-ethene

MW—1 (U) 9/30/86 0.53 0.03 <0.05 — — — — —

MW-1 (S) .8/3/90 — <0.01 — — — — — —

MW-1 (S) 8/30/90 — <0.01 — — — — — —

MW-1 (U) 9/13/90 — <0.02 — — — — — —

MW-1 (S) * 9/13/90— 0.03 — — — — — —

»

MW-1 (N) 3/26/91 — <0.040 <0.05 — — — — —

MW-1 (N) 3/26/91 — (<0.04 0) (<0.05) — — — — —

MW-1 (S) 3/26/91 — 0.03 — — — — — —

MW-1 (S) 3/26/91 — (<0.,01) — — — — —

MW-1 (N) 5/8/91 0.0100 0.0080 <0.050 — <0.0020 0.0030 <0.0020 <0.0020

«

MW-2 (U) 9/30/86 0.08 0.06 <0.05 — — — — —

MW-2 (S) 8/3/90 — <0.01 — — — — — —

ELECTRO-COATINGS SITE-GROUNDWATER CONTAMINANT CONCENTRATION (mg/1)

Locatior Date Cadmium Chromium(total)

Chromium(VI)

Nickel 1,1-Dichlor-oethene

Cis-1,2- Dichlor- oethene

1,1,1"Trichlor-oethane

Tri-chlor-oethene

MW-2 (S) 8/30/90 — <0.01 — — — — — —

MW-2 (U) 9/13/90 — <0.02 — — — — — —

MW-2 (S) 9/13/90 — 0.01 — — — — — —

MW-2 (N) 3/25/91 — <0.040 <0.050 — — — — —

MW-2 (S) 3/25/91 — <0.01 — — — — — —

MW-2 (N) ■ 3/25/91 — (<0.040) (<0.050) — — — — —

MW-2 (S) ‘3/25/91— (0.01) — — — — —

MW-2 (N) 5/7/91 0.0110 0.0070 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW-3 (U) 9/30/86 <0.02 0.10 <0.05 — — — — —

MW-3 (S) 8/3/90 — <0.01 — — — — — —

«

MW-3 (S) 8/30/90 — <0.01 — — — — — —



Chromium(VI)



1,1,1-Trichlor-oethane

Tri-chlor-oethene

MW-3 (U) 9/13/90 — <0.02 — — — — — —

MW-3 (S) 9/13/90 — 0.01 — — — — — —

MW-3 (N) 3/26/91 — <0.040 <0.050 — — — — —

MW-3 (S) 3/25/91 — 0.08 — — — — — —

MW-3 (N) 3/26/91 — (<0.040) (<0.050) — — — — —

MW-3 (S) 3/25/91 — (<0.01) — — — — — —

MW-3 (N) ‘5/7/91 0.0060 0.0080 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW—4 (U) 9/30/86 <0.02 0.07 <0.05 — — — — —

MW-4(S) 8/30/90 — 0.01> — — — — — —

MW-4 (U) 9/13/90 — <0.02 — — — — — —

MW-4 (S) 9/13/90 — 0.02 — — — — — —

MW-4 (N) 3/25/91 — <0.040 <0.050 — — — — —

MW-4 (S) 3/25/91 — 0.02 — — — — — —



Chromium(VI)

Nickel 1,1"Dichlor-oethene



Tri-chlor-oethene

MW-4(N) 3/25/91 — (<0.040) (<0.050) — — — — —

MW-4 (S) 3/25/91 — (<0.01) — — — — — —

MW-4 (N) 5/7/91 0.002 0.003 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW-5(N) 3/26/91 — <0.050 <0.100 — — — — —

MW-5(N) 3/26/91 — <0.040d <0.lOOd — — — — —

MW-5(S) 3/2 6/91 — 0.21 — — — — — —

MW-5(N) ‘3/26/91 — (0.050) (<0.100) — — — — —

MW—5(N) 3/26/91 — (<0.040) 1 (<0.100) 1 — — — — —

MW-5 (S) 3/26/91 — (0.03) — — — — — —

MW-5 (N) 5/7/91 0.00030 0.0130 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW-5 (N) 9/3/91 — 0.22 0.22 — <0.020 0.076 <0.020 0.028

«MW-5D (N) 9/3/91 — 0.0100 <0.050 — <0.0010 <0.0010 <0.0010 0.0011

MW-5D (N) 9/3/91 — 0.0060d <0.050d — <0.OOlOd <0.OOlOd <0.OOlOd <0.0010c

MW-5D (U) 9/3/91 — <0.02 <0.05 — <0.005 <0.005 <0.005 <0.005



Chromium(VI)


Cis-1,2-Dichlor-oethene


Tri-chlor-oethene

MW-6 (N) 3/26/91 — <0.040 <0.050 — — — — —

MW-6 (S) 3/26/91 — 0.04 — — — — — —

MW-6 (N) .3/26/91 — (<0.040) (<0.050) — — — — —

MW-6 (S) 3/26/91 — (0.02) — — — — — —

MW-6 (N) 5/8/91 0.002 0.0150 <0.050 — <0.050 <0.050 <0.050 <0.050

MW-6 (N) 5/8/91 0.OOld 0.0120d <0.050d — <0.050d <0.050d <0.050d <0.050d

*

MW-6 (N) ' 9/3/91— 0.074 0.070 — <0.010 <0.010 <0.010 0.013

MW-6D (N) 3/26/91 — 0.650 0.600 — — — — —MW-6D(S) 3/26/91 — 0.74 — — — — — —MW- 6 D (N) 3/26/91 — (0.650) (0.600) — — — — ■—

MW- 6 D (S) 3/26/91 — (0.65) — — — — — —

MW-6(N) 5/8/91 0.0080 0.6050 0.610 — <0.0050 * <0.0050 <0.0050 0.010

MW-6(N) 5/8/91 0.0080d 0.6400d 0.610d — <0.0050d <0.0050d <0.0050d 0.0099d

MW-6(U) 5/8/91 — 0.54 0.26 — <0.005 <0.005 <0.005 .011



Chroming(VI)




Tri-chlor-oethene

MW-6D (N) 9/3/91 — 0.47 0.47 — <0.0020 <0.0020 <0.0020 0.0058

MW-6D(U) 9/3/91 — 0.45 0.49 — <0.005 <0.005 <0.005 0.007

MW-7 (N) 3/26/91 — 0.650 0.600 — — — — —

MW-7 (S) 3/26/91 — 0.69 — — — — — —

MW—7 (N) 3/26/91 — (0.600) (0.600) — — — — —

MW-7 (S) 3/26/91 — (0.65) — — — — — —

MW—7 (N) '5/8/91 0.0020 0.210 0.270 0.024 <0.0020 <0.0020 <0.00200 0.0146

MW—7 (U) 5/8/91 — 0.24 0.24 — <0.005 <0.005 <0.005 0.015

MW-7 (N) 9/3/91 — 1.7 1.7 — <0.001 0.013 0.0093 0.066

>

MW-8 (N) 3/26/91 — <0.040 <0.050 — — — — —

MW-8 (S) 3/26/91 — 0.03 — — — — — —

MW-8 (N) 3/25/91 — (<0.040) (<0.050) — ♦ — — —

MW—8 (S) 3/25/91 — (0.01) — — — — — —

MW-8 (N) 3/25/91 —

000V 0

in

. 00VTS d — — — — —

MW-8 (S) 3/25/91 — (<0.01)d — — — — — —



Chromium(VI)



1,1,1“Trichlor-oethane

Tri-chlor-oethene

MW-8 (N) 5/7/91 0.0010 0.0040 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW-8 (N) 9/3/91 — 0.0090 <0.050 — <0.0010 <0.0010 0.0017 0.0059

MW-8D (N) 3/25/91 — <0.040 <0.050 — — — — —

MW-8D(S) 3/25/91 — 0.03 — — — — — —

MW-8D (N) 3/25/91 — (<0.040) (<0.050) — — — — —

MW-8D (S) : 3/25/91 — (<0.01) — — — — — —

l

MW-8D(N) 5/7/91 0.005 0.003 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW-8D (N) 9/3/91 — 0.0020 <0.050 — <0.0010 <0.0010 <0.0010 0.0011

MW-9 (N) 3/25/91 — 34 25 — <0.050 0.106 <0.050 0.112

MW-9 (S) 3/25/91 — 26 — — — — — —

MW-9 (N) 3/25/91 — (31) (25) — ““ f — — —

MW-9 (S) 3/25/91 — (24.3) — — — — — —



Chromium(VI)

NickelDichlor-oethene



Tri-chlor-oethene

MW-9 (N) 5/8/91 0.0160 14 13 0.199 0.018 0.356 0.104 0.694

MW-9 (U) 5/8/91 — 13 13 — 0.033 0.560 0.160 0.890

MW-9 (N) 9/3/91 — 10 5.4 — 0.0010 0.170 0.041 0.280

MW-10(N) 3/26/91 — <0.040 <0.050 — — — — —

MW-10(S) 3/26/91 — 0.10 — — — — — —

MW-10(N) •3/26/91 — (<0.040) (<0.050) — — — — —

MW-10(S) ‘3/26/91— (0.03) — — — — — —

MW-10(N) 5/7/91 0.003 0.0370 <0.050 — <0.0020 <0.0020 0.0162 0.0076

MW-10(N) 9/3/91 — 0.03,00 <0.050 — 0.0046 <0.0010 0.063 0.056

1 H O S' 3/26/91 — <0.040 <0.050 — — — — —

MW-10D^j) 3/26/91 — <0.040d <0.050d —_ _ *

— — —MW-10D^) 3/26/91 — 0.07 — — — — — —MW-10D^l) 3/26/91 — (<0.040) (<0.050) — — — — —MW-10D^I) 3/26/91 —

oooV 3(<0.050) a — — — — —


Locatior Date Cadmium Chromium (total)

Chromium(VI)




Tri-chlor-oethene

MW-10DS 3/26/91 — (0.01) — — — — — —

MW-10DN .5/7/91 0.0050 0.0060 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

MW-10DN 9/3/91 — 0.0080 <0.0050 — <0.0010 <0.0010 <0.0010 <0.0010

MW-11(U 9/30/86 0.23 1.3 <0.05 — — — — —

MW-11(St

8/31/90 — 0.02 — — — — — —

MW-11(N 9/3/91 — 4.1 4.1 — 0.0082 0.0068 0.061 0.063

MW-11(U 9/3/91 — 3.8 5.0 — 0.008 0.008 0.056 0.055

>

PW-l(U) 10/1/86 <0.02 1.3 1.3 — — — — —

PW-l(U) 10/1/86 <0.02d 1.3d 1.3d — — — — —4

PW-l(U) 9/3/90 — 1.2 — — — — — —

PW-l(S) 9/30/90 — 1.26 — — — — — —


Location Date Cadmium Chromium(total)

Chromium(VI)




Tri-chlor-oethene

PW-l(N) 3/26/91 — 2.5 <0.050 — — — — —

PW-l(S) 3/26/91 — 2.8 — — — — — —

PW-l(N) 5/8/91 <0.0010 1.7 1.6 — <0.0050 <0.0050 <0.0050 0.0259

PW-l(U) 5/8/91 — 1.3 1.8 — <0.005 <0.005 0.010 0.028

PW-l(N) 9/3/91 — 0.71 0.70 — <0.001 0.0016 0.0034 0.015

PW-2(U) '9/13/90 — <0.02 — — — — —

PW-2(S) 9/13/90 — <0.01 — — — — — —

PW—2(N) 3/26/91 — <0.040 <0.050 — — — — —

PW—2(S) 3/26/91 — <0.01 — — — — —

PW—2(N) 5/8/91 <0.0010 0.0020 <0.050 — <0.0020 <0.0020 <0.0020 <0.0020

«

GP-l(U) 9/30/90 <0.02 21 — 0.16 — — — —

GP-l(S) 9/30/90 — 22 — — — — — —



Chromium(VI)




Tri-chlor-oethene

GP-l(U) 9/30/90 (<0.02) (21) — 0.17 — — — —

GP-l(S) 9/30/90 — (22) — — — — — —

GP-2(U) 9/30/90 — <0.02 — — — — — —

GP-2(S) 9/30/90 — 0.02 — — — — — —

GP-2(U) 9/30/90 — (<0.02) — — — — — —

GP-2(S) 9/30/90 — (<0.01) — — — — — —

GP-3S(U) 9/30/90 — 0.08 — — — — —

GP-3£(S) 9/30/90 — 0.08 — — — — — —

GP-3£(U) 9/30/90 — (0.03) — — — — — —

GP-3£(S) 9/30/90 — (0.03) — — — — — —

GP-3D(U) 9/30/90 — (<0.02) — — — — — —

GP-3D( S) 9/30/90 — (<0.01) — — — — — —

ELECTRO-COATINGS SITE- GROUNDWATER CONTAMINANT CONCENTRATION (mg/1)


Chromium(VI)




Tri-chlor-oethene

GP-4(U) 9/30/90 — 0.02 — — — — — —

GP-4(S) 9/30/90 — 0.04 — — — — — —

GP-4(U) 9/30/90 — (<0.02) — — — — — —

GP-4(S) 9/30/90 — (0.01) — — — — — —

CW-l(U) 9/30/86 <0.02 <0.02 <0.05 — — — — —

CW-6(U) 8/13/90 — — <0.05 — — — — —


Locatior(Lab)

Date Cadmium Chromium (total)

Chromium(VI)

Nickel 1,1-Dichlor—oethene



Tri-chlor-oethene

B-ll 8/20/91 — <0.04 <0.05 — <0.200 <0.200 <0.200 <0.200

B-12 8/20/91 — <0.04 <0.05 — <0.200 <0.200 <0.200 <0.200

B-13 8/20/91 — <0.04 <0.05 — <0.100 <0.100 <0.100 <0.100

B—15 8/20/91 — <0.470 • <0.520 — <0.010 <0.010 <0.010 <0.010

B-16 8/20/91 — <0 o 04 <0.05 — <0.020 <0.020 <0.020 0.0414

B-17 8/20/91 — 0.200 <0.05 — 0.00845 0.00965 0.0172 0.0511

NOTE:Samples collected from open boreholes.

ELECTRO-COATINGS SITE-SURFACE WATER CONTAMINANT CONCENTRATION (mg/1)


Chromium(VI)




Tri-chlor-oethene

SW (1) (U )9/30/86 <0.02 <0.02 <0.05 — — — — —

SW-l(N) 5/8/91 0.008 0.0880 <0.050 <0.010 <0.0020 <0.0020 0.0024 <0.0020

SW-l(U) 5/8/91 — <0.02 <0.05 — — — — —

SW-l(S) 6/14/91 — <0.01 — — — — — —

SW-l(N) 9/3/91 — 0.0020 <0.050 — — — — —

SW-2(N) 5/8/91 0.002 0.0050 <0.050 <0.010 <0.0020 <0.0020 <0.0020 <0.0020

SW-2(N) 5/8/91 — <0.02d <0.050d — — — — —

(1) Sample from Cedar Lake along the shore at the mid-pointof the Hawkeye Rubber property.

• • •

ELECTRO-COATINGS SITE- CEDAR LAKE SEDIMENT CONTAMINANT CONCENTRATION (mg/kg)


Chromium(VI)




Tri-chlor-oethene

S-l(U) 9/30/86 <2 28 — — — — — —

S-2(U) 9/30/86 <2 68 — — — — — —

SD-l(N) 5/8/91 <1.0 12 <1.0 2.2 <0.1 <0.1 <0.1 <0.1

SD-2(N) 5/8/91 <1.0 3.9 <1.0 2.3 <0.11 <0.11 <0.11 <0.11

S-l: Located on the east edge of the Hawkeye Rubber Co. property.

S-2: Located midpoint of the Hawkeye Rubber Co. property.

ELECTRO-COATINGS SITE- SOIL CONTAMINANT CONCENTRATION (mg/kg)


Chromium(VI)



1,1,1“Trichlor-oethane

Tri-chlor-oethene

B-l(N) 2/25/91 — 4.8 <1.0 — — — — —

B-2(N) 2/25/91 — 5.0 <1.0 — — — — —

B-3(N) 2/25/91 — 4.8 <1.0 — — — — —

B-4a(N) 2/25/91 — 8.5 <1.0 — — — — —

B-4b(N) 2/25/91 — 6.8 <1.0 — — — — —

B-ll(N) 8/19/91 — 4.2 <2.5 — <0.5 <0.5 <0.5 <0.5

B-12(N) 8/19/91 — 4.5 <2.5 — <0.5 <0.5 <0.5 <0.5

B-13(N) 8/19/91 — 2.7 <2.5 — <0.5 <0.5 <0.5 <0.5

B-14(N) 8/19/91 — 23 <2.5 — <0.5 <0.5 <0.5 <0.5

B-15(N) 8/20/91 — 4.9 <2.5 — <0.5 <0.5 <0.5 <0.5

ELECTRO-COATINGS SITE- SOIL CONTAMINANT CONCENTRATION (mg/kg)

Locatior(Lab)

Date Cadmium Chromium(total)

Chromium(VI)




Tri-chlor-oethene

B-16(N) 8/20/91 — 5.0 <2.5 — <0.5 <0.5 <0.5 <0.5

B-17(N) 8/20/91 — 24 8.0 — <0.5 <0.5 <0.5 <0.5

ES2/6(U) 6/25/92 — — — — <0.005 <0.005 <0.005 0.008

HS2/9(U) 6/24/92 — — — — <0.005 0.020 <0.005 <0.005

HS2/6(U) 6/24/92 — — — — <0.005 0.200 <0.005 0.009

HS2/6* (l J6/24/92 — — — — <0.025 <0.025 <0.025 <0.025

HS2/3(U) 6/24/92 — — — — <0.005 0.790E <0.005 0.026

HS2/3* (I )6/24/92 — — — — <0.025 0.780 <0.025 <0.025

* Similar to a duplicate sample but collectedat a slightly different depth.

E - Estimated concentration.

BASELINE RISK ASSESSMENTThe objective of this Baseline Risk Assessment is to evaluate the potential...

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