SALLY J. PEDERSON LT. GOVERNORDEAF RELAY (hearing or speech impaired) 1-800-735-2942 / INTERNET: ......

SALLY J. PEDERSON

LT. GOVERNORJanuary 25, 2000

Daniel J. Garvey, O.S.C EFLR/Superfund Division EPA, Region VII 901 N 5th Street

Kansas City, KS 66101

Re: Revised PRGs for Bernstein Salvage SiteOskaloosa, IA

Dear Mr. Garvey:

Enclosed please find a copy of revised PRGs for the Bernstein Salvage Site, Oskaloosa, IA. Please note that the PRGs for the commercial/industrial land use have been revised due to an error in the assumption. However, the PRGs for other land’use exposure scenarios remain the same. For your information, PRGs for Various Land Uses are summarized in the following tables.

Table 1: PRGs Summary Table for Various Land Uses(HQ=0.1 TR=10‘6)

Contaminants Residential Land Use

Commercial Land Use

ApartmentComplex

FireStation

CityPark

Antimony 10.7 79.1 28.7 100 16.6Arsenic 0.397 3.46 2.16 4.93 1.74Lead 420 1354 - - 11684, 4-DDT 1.75 15.3 9.53 21.8 7.68Dieldrin 0.032 0.267 0.182 0.415 0.121Heptachlor Epoxide 0.056 0.469 0.32 0.73 0.213Total PCBs 0.236 1.94 1.37 3.14 0.846Benzo(a)anthracene 0.659 5.43 3.82 8.71 2.39Benzo(a)pyrene 0.0659 0.543 0.382 0.871 0.239Benzo(b)fluoranthene 0.659 5.43 3.82 8.71 2.39Dibenz(ah)anthracene 0.0659 0.543 0.382 0.871 0.239Indeno(l,2,3 c-d)pyrene

0.659 5.43 3.82 8.71 2.39

LUCAS STATE OFFICE BUILDING / 321 E. 12TH ST. / DES MOINES, IOWA 50319-0075 DEAF RELAY (hearing or speech impaired) 1-800-735-2942 / INTERNET: http://idph.state.ia.us/

Family & Community Health Administration & Regulatory Affairs Substance Abuse & Health Promotion Executive Staff Director's Office 515-281-3931 515-281-5784 515-281-3641 515-281-5604 515-281-5605

fax/515-242-6384 fax/515-281-4958 fax/515-281-4535 fax/515-281-4958 fax/515-281-4958

Table 2: PRGs Summary Table for Various Land Uses(HQ=0.1 TR=10'5)

Contaminants Residential Land Use

Commercial Land Use

ApartmentComplex

FireStation

CityPark

Antimony 10.7 79.1 28.7 100 16.6Arsenic 3.97 34.6 20.8 49.3 11.2Lead 420 1354 - - 11684, 4-DDT 12.7 92.7 34.7 122 18.7Dieldrin 0.32 2.67 1.82 4.15 1.21Heptachlor Epoxide 0.284 1.98 0.81 2.84 0.36Total PCBs 2.36 19.4 13.7 31.4 8.46Benzo(a)anthracene 6.59 54.3 38.2 87.1 23.9Benzo(a)pyrene 0.659 5.43 3.82 8.71 2.39Benzo(b)fluoranthene 6.59 54.3 38.2 87.1 23.9Dibenz(ah)anthracene 0.659 5.43 3.82 8.71 2.39Indeno(l,2,3 c-d)pyrene

6.59 54.3 38.2 87.1 23.9

If you have any questions concerning the revision, please feel free to contact me at 515-281 8707.

Sincerely, .

Michelle X. Wei

THOMAS J. VILSACK DEPARTMENT OF PUBLIC HEALTHGOVERNOR STEPHEN C. GLEASON, D.O., DIRECTOR

SALLY J. PEDERSON

LT. GOVERNOR

MEMORANDUM

DATE:

TO:

FROM:

RE:

January 25,2000

Daniel J. Garvey, On-Scene CoordinatorEFLR/Superfund DivisionEPA, Region VII901 N 5th StreetKansas City, KS 66101

Michelle WeiIowa Department of Public Health

Preliminary Remedial Goals (PRGs)The Bernstein Salvage Site Oskaloosa, Iowa

INTRODUCTION

The Environmental Protection Agency (EPA) is considering the need for a removal action at the above referenced site. The Iowa Department of Public Health (IDPH) was requested to provide assistance in calculating the Preliminary Remedial Goals (PRGs) for the site.

The PRG calculations were based on very limited information provided in Trip Report with Data Summary for the Site Reconnaissance/Limited Characterization of the Bernstein Salvage Site,Oskaloosa, IA (Ecology and Environment, Inc.) and Environmental Site Assessment Limited Phase II (Maxim Technologies Inc./Patzig Testing). Heavy metals, pesticides, polychlorinated biphenyls (PCBs), and polynuclear aromatic hydrocarbons (PAHs) were detected in surface and subsurface soils. PRGs were calculated for surface soil only. The site is currently zoned as commercial/industrial land use. The potential future land use for the site is an uncertainty.Based on conversations with the City Manager's office, the following options may be considered for the future land uses: (a) a city park with a biking trail and a small play area for children 10 years of age and younger; or (b) an apartment complex for senior citizens 60 years of age and older who can live independently; or (c) a fire station. According to the office, the potential for the site to be used for a future single family home is slim. Due to the uncertainties involved at the site, the potential land uses suggested by the City Manager and residential, industrial/commercial land uses were considered for the PRG calculations. EPA Risk

LUCAS STATE OFFICE BUILDING / 321 E. 12TH ST. / DES MOINES, IOWA 50319-0075 DEAF RELAY (hearing or speech impaired) 1-800-735-2942 / INTERNET: http://idph.state.ia.us/

Family & Community Health administration & Regulatory AFFAiRsPag6ifeefr®0E Abuse & Health Promotion Executive Staff Director’s Office 515-281-3931 515-281-5784 515-281-3641 515-281-5604 515-281-5605

fax/515-242-6384 fax/515-281-4958 fax/515-281-4535 fax/515-281-4958 fax/515-281-4958

Assessment Guidance for Superfund, Human Health Evaluation Manual, Volume I, Part B: “Development of Risk Based Preliminary Remediation Goals” was followed. For the contaminant lead, EPA Guidance Manual for the Integrated Exposure Uptake Biokinetic Model (IEUBK) for Lead in Children, and Methodology for Assessing Risks Associated with Adult Exposures (MARAAE) to Lead in Soil were applied for the calculations.

SITE BACKGROUND

The Bernstein Salvage site is located in a residential district in Oskaloosa, Iowa. The site is bounded to the north by First Avenue, to the east by South E Street, to the south by Third Avenue, and to the west by active railroad tracks. The geographic coordinates are latitude 41°15'30" North and longitude 92°39'02" West. The site is rectangular in shape, measuring approximately 400 by 500 square feet. The site is no longer active and access to the site is unrestricted.

According to Bernstein and family friend Bob Lynn, the property has been in the possession of the Bernstein family since approximately 1950, and has since been utilized solely for salvage purposes (see Figure 1). The buildings at the northeastern end of the property were utilized for the storage of car batteries, while the structures in the northwestern section had housed a gasoline station (this information was verified by a 1950 Sanborn Fire Insurance map). The original Bernstein property to the southwest of the site had been a salvage yard since sometime prior to 1950. Two truck scale pits had been located on site, but neither Bernstein nor Lynn was aware of any underground storage tanks. Aboveground tanks may possibly have been associated with a Farm Services business (filling station), which was also in the northwest portion of the site. Neither Lynn nor Bernstein was aware of any transformers being present on the property (this was also verified later by a neighboring property owner who resided adjacent to the site for 34 years). In addition, neither individual had knowledge of pesticides being used or stored on the property. The only agricultural use that had taken place on the site was a brief period of poultry processing.

Historical information indicates that the south portion of the site was used primarily for rubbish piles. It also indicates that Seever Manufacturing purchased the property in 1867 for manufacturing boiler and steam systems, and bridge works. Prior to Seever Manufacturing, an unnamed foundry was located on the property.

In 1998, Lynn arranged for a private contractor to perform soil sampling to determine whether any contamination was present on site. Lynn contracted Maxim, which took 10 surface soil samples from various locations on August 26, 1998 to perform a limited characterization of contaminants that might be present on the site. These samples were analyzed for benzene, toluene, ethyl benzene, and xylenes (BTEX), total extractable hydrocarbons (THE), polychlorinated biphenyls (PCBs), and total lead/cadmium. Shortly thereafter, Bernstein arranged for several contractors to remove the structures and debris from the site. Stevens

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Concrete removed the bulk of the material, demolishing all structures, concrete pads, scales, pits, and transporting the same to the city landfill. The surface was then graded using soil present on the site to fill any resulting pits and low spots. No foreign soil was brought in as backfill. Currently, the site is relatively flat, with no structures of any kind. All railroad tracks have been removed. Remains of small scrap metal items are scattered across the site (pistons, chains, metal car parts) often protruding from the ground. All scales and pits have been removed and filled. Two sealed 55-gallon drums of "crater grease" (used for lubricating trenching equipment) were on site, which Bernstein is presently attempting to sell (containers are intact, sealed, and in good condition).

Site reconnaissance/limited characterization of the site was conducted on March 29 and April 1, 1999. Historical data and visual information, such as soil staining and surface rubbish, was used for selecting locations for in situ lead screening; Approximately 20 locations were screened with most lead concentrations ranging between 30 ppm to 500 ppm. At select locations, a high above 2,000 ppm was recorded, as well as readings below 300 ppm. Twelve of screened locations were selected for sampling and submitted for total lead analysis. Of these, the five samples with the highest XRF readings were selected to be analyzed for total metal concentrations in addition to lead. Nine surface soil samples were collected and submitted for PCBs and pesticides analysis. Ten surface soil samples were collected and submitted for semi-volatiles (PAHs) analysis. Analysis results indicated that some heavy metals, PAHs, and PCBs were detected at above soil screening levels.

CHEMICALS OF POTENTIAL CONCERN (COPCs)

Based on the data collected, chemicals found above the EPA Region IX Preliminary Remediation Goals Tables are selected as COPCs for the site. The following COCs are identified with a brief explanation as to why each chemical was included:

TABLE 1 Summary of Chemicals of Potential Concern at the Site

Chemical Rational (media of contaminant detected)Antimony SoilArsenic SoilLead Soil4,4-DDT SoilDieldrin SoilHeptachlor Epoxide SoilTotal PCBs SoilBenzo(a)anthracene SoilBenzo(a)pyrene SoilBenzo(b)fluoranthene SoilDibenz(ah)anthracene SoilIndeno( 1,2,3-cd)pyrene Soil

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REASONABLE MAXIMUM EXPOSURE SCENARIOS (RME)

The RME is an estimate of the highest exposure that is reasonably expected to occur at a site. Exposure to a contaminant is defined as the contact of a receptor with a contaminant. In order for the exposure to occur, there must be a source of contaminant (e.g., contaminated groundwater), a receptor (a person), and a mechanism (pathway) for the contaminant to reach the receptor (such as a person drinking the contaminated groundwater). The potentially contaminated media based on the available data include surface and subsurface soils. Potential human receptors may include future on-site residents, commercial/industrial workers, senior citizen residents, fire station employees, and city park users. Exposure pathways may include incidental ingestion, dermal contact, and inhalation of fugitive dust generated from the contaminated soil. Due to the vegetation cover and contaminant properties present at the site, exposure pathway from inhalation of fugitive dust is negligible, thus not considered for the PRG calculations.

Five potential RME scenarios were considered for contaminants other than lead. RME1, future residents live in the area 350 days per year over a period of 30 years. Two exposure groups children of one to six years, and others of seven to 31 years were considered due to different soil ingestion rate, body surface area, and soil adherence factor. It was assumed that the site would be used for a single family home. RME2, a future on-site worker works at the site 250 days per year over a period of 25 years of his or her life span. He or she was exposed to contaminants by incidental ingestion of soil at the rate of 50 mg and exposing to contaminated soil and dust through head, forearms, lower legs, and hands everyday. It was assumed that the site would remain industrial/commercial land use. RME3, a senior citizen resides on the site 350 days per year for 15 years. He or she spends most of his/her time at the site, ingesting 100 mg soil and dust and contacting soil and dust on hands, forearms, lower legs, and head everyday. It was assumed that the site would be used to build an apartment complex for senior citizens who are 60 years and older and can live by themselves independently. RME4, a fire station employee works at the site 2 days per week (on 24 hours on and 48 hours off cycle), 50 weeks per year (2 days/week x 50 weeks/year=100 days/year) over 23 years of his or her life. The person would spend 24 hours on the site during working day, ingesting soil and dust 100 mg and exposing to soil and dust through dermal contact. It was assumed that the site would be used to build a fire station. RME5, a child 10 years or younger plays at site, 5 times per week from April to November (five hours per week, 35 weeks per year, 175 hours/year). The child is assumed to ingest soil and dust 200 mg and contact soil through forearms, lower legs, hands, and head when he or she is playing at he site. It was assumed that the site would be developed to a city park with a biking trail and a play area for children who are 10 years and younger. It was also assumed that the fraction of contaminated soil ingested is 0.5 (50% of soil ingested was from the park).

For lead, the IEUBK model was used to assess children of 84 month old or less for RME1 and RME 5. The EPA Methodology for Assessing Risks Associated with Adult Exposures to Lead in Soil was used for the PRG calculations for RME2. Same exposure scenarios as the aforementioned were considered. However, a child-bearing age or a pregnant woman was considered as the receptor. It was assumed that a child-bearing age or a pregnant woman works at the office (commercial/industrial land use) and the fire station, respectively. It was assumed

Page 4 of20

that the work force is relatively homogenous and the female worker is mixed racial. For RME3, RME4, PRG for lead was not calculated due to the lack of EPA methodology for assessing risk for residential adults.

METHODOLOGY

The IEUBK model was used to assess children of 84 month old or less for RME1 and RME 5. The IEUBK Model for lead in children is a standing alone, PC compatible software package. It allows the user to estimate, for a hypothetical child or population of children, a plausible distribution of blood lead concentrations centered on the geometric mean blood lead concentration predicted by the model from available information about children’s exposure to lead. From this distribution, the model calculates the probability that children’s blood lead concentrations will exceed the user defined level of concern (default 10 pg/dL). The user can then explore an array of possible changes in exposure media that would reduce the probability that blood lead concentrations would be above this level of concern. It is designed to model exposure from lead in air, water, soil, dust, paint, diet, and other sources with pharmacokinetic modeling to predict blood lead levels in children 6 months to 7 years old.

Blood lead concentrations are not only indicators of recent exposure, but also are the most widely used index of internal lead body burdens associated with potential health effects. Health effects of concern have been determined to be associated with childhood blood lead concentrations at or below 10 pg/dL (EPA, 1986, 1990; CDC, 1991). The probability that children will have blood lead levels exceeding this level of concern is an important consideration for a risk assessor in compiling and evaluating all information applicable to a site to enable cleanup decisions.

The IEUBK Model was applied to RME1 and RME5 to determine soil lead concentrations in order to reduce the likelihood of exceeding a blood lead level of concern (LOC=10 pg/dL) to the user-defined risk of exceedance (ROE=5.00%) of the LOC at the site.

The EPA Methodology for Assessing Risks Associated with Non-residential Adult Exposures to Lead in Soil was applied for RME2. The approach utilized a methodology to relate soil lead intake to blood lead concentrations in women of child-bearing age. The target blood lead concentration is intended to protect against developmental effects of lead that might result from the exposure of a fetus to lead in utero when a pregnant woman works at the site.

The risk-based Preliminary Removal Goals (PRGs) other than Lead were calculated using EPA’s Risk Assessment Guidance for Superfund (RAGS), Volume I, Part B. PRGs were calculated based on a 10‘6 cancer risk level and a hazard quotient (HQ) of 0.1 for soil incidental ingestion and dermal pathways. Some of the COPCs (such as Arsenic) at the site are potential carcinogens. Carcinogens may also cause non-carcinogenic effects to certain exposed individuals. When it was possible, both carcinogenic and non-carcinogenic risk-based PRGs were calculated for a particular chemical. PRG is set at the lower value between carcinogenic and non-carcinogenic risk-based PRGs.

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For the oral ingestion pathway, a “Reference Dose” (RfD) and a “Slope Factor” (SF) were used for non-carcinogenic and carcinogenic cleanup level calculations, respectively. In general, the RfD is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. RfD can also be derived for the non- carcinogenic health effects of compounds which are also carcinogens. The SF is a numeric representation of the potential for chemicals to cause excess cancer (above background) in the exposed human population. Both RfDs and SFs were obtained from either EPA IRIS, the Health Effects Assessment Summary Table (HEAST), or the National Center for Environmental Assessment (NCEA). Oral RfDs and SFs were used for dermal exposure pathway due to the lack of quantitative toxicity information from EPA. Table 2 summarizes the RfDs and SFs used for the PRG calculations.

Table 2. Summary of Reference Doses and Slope Factors Used in PRG Calculations

Chemicals Non-carcinogenic toxicity Carcinogenicity Source

ChronicRfD

Critical effect oral slopefactor

weight -of evidence classification

Unit mg/kg-day (mg/kg-day^1

Antimony 4.0E-04 Longevity, blood glucose and cholesterol

" * IRIS

Arsenic 3.0E-04 Keratosis,hyperpigmentation

1.5E+00 A IRIS

4,4-DDT 5.0E-4 Liver lesion 3.4E-01 B2 IRIS

Dieldrin 5.0E-5 Liver lesion 1.6E+01 B2 IRIS

HeptachlorEpoxide

1.3E-5 Increaded liver to body ratio

9.1E+00 B2 IRIS

Total PCBs - - 2.0E+00 B2 IRIS

Benzo(a)anthracene - - 7.30E-01 B2 NCEA

Benzo(a)pyrene - - 7.30E+00 B2 NCEABenzo(b)fluoranthene - - 7.30E-01 B2 NCEA

Dibenz(ah)anthracene - - 7.30E+00 B2 NCEA

Indeno( 1,2,3 c-d)pyrene

* * 7.30E-01 B2 NCEA

CALCULATIONS AND RESULTS

The EPA’s Integrated Exposure Uptake Biokinetic Model (IEUBK) for lead in children and the EPA Methodology for Assessing Risks Associated with Non-residential Adult Exposures to Lead in Soil were used for PRGs calculation for Lead. The surface soil risk-based Preliminary Removal Goals (PRGs) other than Lead were calculated using EPA’s Risk Assessment Guidance for Superfund (RAGS), Volume I, Part B. PRGs were calculated based on a 10'6 cancer risk level and a hazard quotient (HQ) of 0.1 for soil incidental ingestion and dermal exposure pathways. Some of the COCs (such as Arsenic) at the site are potential carcinogens. Carcinogens may also cause non-carcinogenic effects to certain exposed individuals. When it was possible, both a carcinogenic and a non-carcinogenic risk-based PRGs were calculated for a particular chemical and PRG is set at the lower value between the two. Specific equations and parameter values used for the calculations are indicated in the attachment. PRG calculation results are summarized in Tables A-l to A-6.

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For the residential land use, it was assumed that the resident was exposed to the contaminated soil over a period of 30 years via soil ingestion and dermal contact. Two exposure groups - children of one to six years and others of seven to 31 years were considered due to different soil ingestion rate, body surface area, and soil adherence factor. It was assumed that the children group was exposed to soil at the rate of 200 mg per day over a period of 6 years, and the other group was exposed to soil at the rate of 100 mg per over a period of 24 years. The IEUBK model was used to determine PRG result for lead. EPA standard default values for soil ingestion rate, body weight, average time, exposure frequency, exposure duration, body surface area, soil adherence factor for residential exposure scenarios were used. Specific equations and parameter values used for the calculations are indicated in the attachment. PRG calculation results are summarized in Table A-l. The PRG results are summarized in Table 3.

Table 3 Summery of PRGs Calculation Results for the Residential Land Use

Contaminants PRGs in mg/kg PRGs in mg/kg(HQ=0.1, (HQ=0.1,TR=10'6) TR=10"5)

Antimony 10.7 10.7Arsenic 0.397 3.97Lead 420 4204, 4-DDT 1.75 12.7Dieldrin 0.032 0.32Heptachlor Epoxide 0.056 0.284Total PCBs 0.236 2.36Benzo(a)anthracene 0.659 6.59Benzo(a)pyrene 0.0659 0.659Benzo(b)fluoranthene 0.659 6.59Dibenz(ah)anthracene 0.0659 0.659Indeno(l,2,3 c-d)pyrene 0.659 6.59

For the Commercial/Industrial land use, it was assumed that a 70 kg future on-site worker works 250 days per year, and was exposed to contaminants by incidental ingestion and dermal contact of soil and dust over a period of 25 years of his or her life time. EPA standard default values for soil ingestion rate, body weight, average time, exposure frequency, exposure duration, body surface area, soil adherence factor for industrial/commercial exposure scenarios were used. EPA Methodology for Assessing Risks Associated with Non-residential Adult Exposures to Lead in Soil was used for PRGs calculation for Lead. Specific equations and parameter values used for the calculations are indicated in the attachment. PRG calculation results are summarized in Tables A-2 and A-6. The PRG results are summarized in Table 4.

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Table 4 Summery of PRGs Calculation Results for Commercial/Industrial land Use

Contaminants PRGs in mg/kg (HQ=0.1, TR=1 O'6)

PRGs in mg/kg (HQ=0.1, TR=10'5)

Antimony 79.1 79.1Arsenic 3.5 35Lead 1354 13544, 4-DDT 15.3 92.7Dieldrin 0.267 2.67Heptachlor Epoxide 0.469 1.98Total PCBs 1.94 19.4Benzo(a)anthracene 5.43 54.3Benzo(a)pyrene 0.543 5.43. ■■Benzo(b)fluoranthene 5.43 54.3Dibenz(ah)anthracene 0.543 5.43Indeno(l,2,3 c-d)pyrene 5.43 54.3

For an Apartment Complex for Senior Citizens, it was assumed that a senior resident lives at the apartment complex 350 days per year over a period of 15 years. He or she was exposed to contaminants by incidental ingestion and dermal contact with soil and dust everyday. EPA standard default values for soil ingestion rate, body weight, exposure frequency, body surface area, soil adherence factor for residential adults were used. Exposure duration of 15 years was based on national average life span of 75 years. It was assumed that only resident over 60 years and old could move to the apartment complex. Specific equations and parameter values used for the calculations are indicated in the attachment. Due to the lack of EPA methodology for assessment residential exposure-to lead, PRG for lead was not calculated for this exposure scenario. PRG calculation results are summarized in Tables A-3. The PRG results are summarized in Table 5.

Table 5 Summery of PRGs Calculation Results for an Apartment Complex

Contaminants PRGs in mg/kg (HQ=0.1, TR=10'6)

PRGs in mg/kg(HQ=0.1, TR=10"5)

Antimony 28.7 28.7Arsenic 2.16 20.8Lead - -4, 4-DDT 9.53 34.7Dieldrin 0.182 1.82Heptachlor Epoxide 0.32 0.81Total PCBs 1.37 13.7B enzo(a)anthracene 3.82 38.2Benzo(a)pyrene 0.382 3.82Benzo(b)fluoranthene 3.82 38.2Dibenz(ah)anthracene 0.382 3.82Indeno(l,2,3 c-d)pyrene 3.82 38.2

I

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For a fire station land use, it was assumed that a fire station employee worked at the site on a 24 hour on and 48 hour off shift over 23 years and was exposed to contaminated soil and dust via dermal contact and accidental ingestion. EPA standard default values for soil ingestion rate, body weight, exposure frequency, body surface area, soil adherence factor for residential adults were used. Specific equations and parameter values used for the calculations are indicated in the attachment. Due to the lack of EPA methodology for assessment residential exposure to lead,

_ PRG for lead was not calculated for this exposure scenario. PRG calculation results are summarized in Tables A-4. The PRG results are summarized in Table 6.

Table 6 Summery of PRGs Calculation Results for a Fire Station

Contaminants PRGs in mg/kg PRGs in mg/kg(HQ=0.1, (HQ=0.1,TR=10"6) TR=10'5)

Antimony 100 100Arsenic 4.93 49.3Lead - -4,4-DDT 21.8 122Dieldrin 0.415 4.15Heptachlor Epoxide 0.73 2.84Total PCBs 3.14 31.4Benzo(a)anthracene 8.71 87.1Benzo(a)pyrene 0.871 8.71Benzo(b)fluoranthene 8.71 87.1Dibenz(ah)anthracene 0.871 8.71Indeno(l,2,3 c-d)pyrene 8.71 87.1

For a city park exposure scenario, it was assumed that a child 10 years or younger played at the play area 5 time a week, 35 weeks per year over a 10 year period and was exposed to soil and dust via incidental soil ingestion and dermal contact. It was assumed that the fraction of contaminated soil ingested was 0.5. EPA standard default values for soil ingestion rate, body surface area, soil adherence factor for residential child were used. Body weigh and exposure frequency values used were based on professional judgement. Specific equations and parameter values used for the calculations are indicated in the attachment. The IEUBK model was used to determine PRG for lead. PRG calculation results are summarized in Tables A-5. The PRG results are summarized in Table 7.

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Table 7 Summery of PRGs Calculation Results for a City Park

Contaminants PRGs in mg/kg(HQ=0.1,TR=10'6)

PRGs in mg/kg(HQ=0.1,TR=10'5)

Antimony 16.6 16.6Arsenic 1.74 11.2Lead 1168 11684, 4-DDT 7.68 18.7Dieldrin 0.121 1.21Heptachlor Epoxide 0.213 0.36Total PCBs 0.846 8.46Benzo(a)anthracene 2.39 23.9Benzo(a)pyrene 0.239 2.39Benzo(b)fluoranthene 2.39 23.9Dibenz(ah)anthracene 0.239 2.39Indeno(l,2,3 c-d)pyrene 2.39 23.9

UNCERTAINTY

Due to the lack of site specific information, EPA default values were used for PRG calculations, which may result under or over estimation of PRGs.

Due to the lack of dermal toxicity information, oral reference dose and slope factor were used for the dermal exposure pathway, it may result over or underestimation of PRGs.

The PRG value for lead for the senior citizen home and fire station exposure scenarios were not calculated due to the lack of EPA methodology of assessing risk for residential exposure to lead. It was assumed that children of 84 month or less would not be present at the senior citizen home or the fire station.

The PRGs for a fire station was based on employee who would be on a 24 hours on and 48 hours off shift. It was assumed that the exposure scenario would be closer to residential exposure than industrial/commercial exposure when the officer is on duty. It may result over estimation of risk.

The default values were applied for the IEUBK model since no site specific data was available, which may result in over or underestimation of lead exposure in children of 84 month old or less.

Page 10 of20

REFERENCE

Recommendation of the Technical Review Workgroup for Lead for an Interim Approach to Assess Risks Associated with Adult Exposures to Lead in Soil, EPA, December 1996.

Review of a methodology for establishing risk-base soil remediation goals for commercial areas of the California Gulch site, U.S. EPA Technical Review Workgroup for Lead, October 1995.

Ecology and Environment, Inc, May 18, 1999, Memorandum to Paul Doherty, EPA Region VII, Trip Report with Data Summary for the Site Reconnaissance/Limited Characterization of the Bernstein Salvage Site, Oskaloosa, IA

Maxim Technologies, Inc./Patzig Testing, Environmental Site Assessment Limited Phase II, Former Bernstein Junkyard, South of 1st Avenue West, East of Railroad Right-of -way, Oskaloosa, IA, Lab No.3609-7-7-4603

EPA Guidance Manual for the Integrated Exposure Uptake Biokinetic Model for Lead in Children, EPA 540-R-93-081, PB93-963510, February 1994

U.S. Environmental Protection Agency, Region VII, Land Use Assumptions in Risk Assessments, July 11, 1997.

EPA Risk Assessment Guidance for Superfund Volume 1, Human Health Evaluation Manual, Part B: “Development of Risk -based Preliminary Remediation Goals”, OSWER Directive 9285.7-01B.

U. S. Environmental Protection Agency, August 1997. Exposure Factors Handbook, Volume I, General Factors. Office of Research and Development, Washington DC 20460, EPA/600/P- 95/002Fa.

U. S. Environmental Protection Agency, August 1997. Exposure Factors Handbook, Volume III, General Factors. Office of Research and Development, Washington DC 20460, EPA/600/P- 95/002Fa.

U.S. Environmental Protection Agency, Integrated Risk Information System, On-line.

U. S. Environmental Protection Agency, FY 1997 Update, July 1997, Health Effects Assessment Summary Tables, EPA-540-R-97, PB97-921199.

U.S. Environmental Protection Agency, January 1992, Dermal Exposure Assessment: Principles and Applications. EPA/600/8-91/01 IB

EPA Risk Assessment Guidance for Superfund Volume I, Human Health Evaluation Manual, Supplemental Guidance, Dermal Risk Assessment, Interim Guidance, EPA/540/1-89/002, June 19,1997.

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Environmental Protection Agency, Office of Health and Environmental Assessment, August 1995, Provisional Guidance for Quantitative Risk Assessment of Polycyclic Aromatic Hydrocarbons, EPA/600/R-93-089, July 1993.

Environmental Protection Agency, National Center for Environmental Assessment, Office of Research and Development, PCBs: Cancer Dose-Response Assessment and Application to Environmental Mixtures. EPA/600/P-96/001F, September 1996,

Page 12 of 20

Attachments

Equations used for risk-based PRG calculations for surface soil:

General Equation for Carcinogenic Effects

C (mg/kg :)=

77? * AT * 365days/yr * 106m

SF*EF*f ED * IR * IF') (ED * 77?, * IF^

BW„+

BW.

(+ ABS *EV*

ED„ * SA„ * AFn ED„ * SAn * AF,— + —

V BW„ BW„

General Equation for Noncarcinogenic Effects

C (mg/kg :)=

THI* R/D* AT* 365days I yr* 106mg! kg

EF-EDa * IRa * IF ~ BW„ +

ED *IR*IFc c

BW„

\ ( + ABS*EV*

.

ED„ * SA„ * AFa ED, * SA„ * AFi

V BW„ BW„

where:

ParametersCTRSFRfDATEFBWCBWaEDCEDaIRcIRa

ABSSACSAaAFCAFa

Definitionchemical concentration in soil mg/kgtarget excess individual lifetime cancer risk (unitless)cancer slope factor (mg/kg-day)'1chronic reference dose (mg/kg-day)average time (year)exposure frequency (days/yr)average body weight for children (kg)average body weight for adult (kg)exposure duration for children (yr)exposure duration for adult (yr)ingestion rate of soil for children (mg/day)ingestion rate of soil for adult (mg/day)absorption fraction (unitless)surface area for children (cm2)surface area for adult (cm )soil adherence factor for children (mg/cm2-event)soil adherence factor for adult (mg/cm2-event)

Page 13 of20

EVIF

event frequency (events/day)fraction of contaminated soil ingested (unitless)

Specific equation and parameter used for the calculations:

For RME1, residential land use:

For carcinogenic effects:

C (mg/kg:)=

TR* AT* 365days/yr * 106nmg/kg

SF*EF*r ED *IR\ -( ED * IR.^

BW,+

abw;

+ ABS* EV*f EDa*SAa*AFn ED, * SAr * AFr ^

C J BW„ BW,

For Non-carcinogenic effects:

C (mg/kg :)=THI* RfD* AT*365days fyr* 106

EF’(ED * IR ^ (ED * IR ^

BW.+

a J BW;+ ABS* EV*

C J

ED.. * SA„ * AFn ED.. * SA.. * A F

\ BW,■ + ■

BW'

mg! kg

Parameters Parameter value

CTRSFRfDATEFBWCBWaEDCEDaIRcIRa

ABSSACSAaAFCAFaEV

chemical concentration in soil mg/kg 10’6chemical specific (mg/kg-day)'1 chemical specific (mg/kg-day)70 years for carcinogens, and equal to ED for noncarcinogens (year) 350 (days/yr)15(kg)70 (kg)6 (yr)24 (yr)200 (mg/day)100 (mg/day)chemical specific (unitless)2900 (cm2)5700 (cm2)0.2 (mg/cm2-everit)0.03 (mg/cm2-event)1 (events/day)

Page 14 of20


For RME2, industrial/commercial land use:

C (mg/kg :)=TR* AT* 365days / yr*\06

SF*EF*f ED„ * IR.

V

A

BW„+ ABS* EV*

( EDa * SAa * AFC ^

BW„

mg I kg


C (mg/kg :)=

Parameters

THI* RfD* AT*365daysI yr* 106

f ED* IR. ^EF1

BWa

Parameter value

+ ABS * EV'*f ED *SA* AF^

=T mg / kg

V BW„

CTRSFRfDATEFBWaEDaIRaABSSAaAFaEV

chemical concentration in soil mg/kg 10'6chemical specific (mg/kg-day)'1 chemical specific (mg/kg-day)70 years for carcinogens, and equal to ED for noncarcinogens (year) 250 (days/yr)70 (kg)25 (yr)50 (mg/day)chemical specific (unitless)5700 (cm2)0.03 (mg/cm2-event)1 (events/day)

Page 15 of 20


For RME3, an apartment complex for senior citizens

C (mg/kg :)=77? * AT* 365days / yr * 106

SF*EF*fEDa*lRa'

BW,+ ABS*EV*

a J

f EDa * SAa * AF ^

BW„

mg I kg


C (mg/kg :)=THI*RJD* AT* 365days I yr* 106

EF'f ED *IR, '

BWr+ ABS*EV*

f ED *SA„*AF?

a J \ BW„

mg I kg


C chemical concentration in soil mg/kgTR 10'6SF chemical specific (mg/kg-day)'1RfD chemical specific (mg/kg-day)AT 70 years for carcinogens, and equal to ED for noncarcinogens (year)EF . 350 (days/yr)BWa 70 (kg)EDa 15 (yr)IRa 100 (mg/day)ABS chemical specific (unitless)SAa 5700 (cm2)AFa 0.03 (mg/cm2-event)EV 1 (events/day)

Page 16 of 20

For RME4, a fire station:


C (mg/kg :)=TR* AT*365days/yr * 106

SF * EF *{ EDa*lRt ^

BW„

(+ABS*EV*

ED„ * SA. * AF„

BW„

mg I kg


THI * RfD* AT* 365days/yr*\06C (mg/kg :)=

Parameters

C

TRSFRfDATEFBWaEDaIRaABSSAaAFaEV

EF-r ED *IR. A

BWa

Parameter valueV y

f EDa*SAa*AFaA

BW„

mg I kg

chemical concentration in soil mg/kg 10’6chemical specific (mg/kg-day)'1 chemical specific (mg/kg-day)70 years for carcinogens, and equal to ED for noncarcinogens (year) 100 (days/yr)70 (kg)23 (yr)100 (mg/day)chemical specific (unitless)5700 (cm2)0.03 (mg/cm2-event)1 (events/day)

Page 17 of20


For RME5, a city park:

C (mg/kg:)=TR* AT* 365days/yr*106

SF*EF*r ED * IR* 1F^

BW„+ ABS*EV*

f EDC * SAC * AFC ^

BWr

mg I kg


C (mg/kg :)= —

EF-

THI * RfD* AT*365days/yr*\06mg;kg ' — * * rr<\ ( ££> * SAr * AF ^ '

ED„ * 1RC * IF

BW„+ ABS*EV*\

BW„


C chemical concentration in soil mg/kgTR 10'6 _jSF chemical specific (mg/kg-day)RfD chemical specific (mg/kg-day)

70 years for carcinogens, and equal to ED for noncarcinogens (year)

EF 175 (days/yr)BWC 21 (kg)EDC 10 (yr)IRC 200 (mg/day)ABS chemical specific (unitless)SAC 2900 (cm2)AFc 0.2 (mg/cm -event)EV 1 (events/day)jp 0.5 (fraction of contaminated soil ingested, unitless)

Page 18 of20

Attachments

PRGs Calculation Results using the IEUBK Model for surface soils contaminated with lead

PRGs was calculated using the IEUBK Model. Default values were used to run the Model (see attachment). The cutoff blood lead level of concern (LOC) is 10 fj.g/dL, and the user defined risk of exceedance (ROE) of the LOC is 5.00% . The target soil lead concentration for the site as a residential area is 420 jj.g/g (ppm). The Model run results are indicated in the following tables and graphs. *

Table 1. Range Finding Run for Target Soil Lead Concentration (plot 1)

overlay plot soil lead concentration (pg/g) probability of exceeding lOpg/dL, percent

1 300 2.872 383 4.423 467 6.034 550 8.255 633 10.616 717 12.817 800 15.45

Table 2 Focused Run for Target Soil Lead Concentration (plot 2)

overlay plot soil lead concentration (pg/g) probability of exceeding1 Opg/dL, percent

1 380 4.152 393 4.423 407 4.704 420 5.005 433 5.326 447 5.677 460 6.03

*The probability of exceeding the lead level of concern (10 pg/dl) is 5.00% of the children population aged seven years old and less at the targeted soil lead concentration.

(1) Land use: Residential land use (RME1)

Assumption: IEUBK model default values were used

PRG for Lead = 420 pg/g (based on IEUBK Model Run result)

Page 19 of20

2) Land use: as a city park used by children 10 years and younger (RME5)

Assumptions: children seven years old or less spent 5 hour per week at the site, the other assumptions would be the same as a residential land use.

Calculation:

PRG for lead = 420 ue/g * 22 hours/wk - 200 fig/g * 17 hours/wk5 hours/wk

=1168 pig/g (ppm)

The IEUBK model (USEPA 1994, Page B-17) assumes children 84 months and less spent about 22 hours outdoor per week. If we assume children under 84 months old spend 5 hours per week at the site, it would leave 17 hours per week outdoors in their yards and other locations. The default value for lead in soil is 200 ppm. Thus assuming 17 hours exposure at 200 ppm and 5 hours exposure at PRG ppm is reasonable. The IEUBK model indicates that exposure to 420 ppm lead in soil for 22 hours per week is acceptable. Therefore, the PRG should be set at the level at which 5 hours per week exposure to PRG ppm, plus 17 hours exposure to 200 ppm results in an equivalent exposure to 420 ppm for 22 hours per week. The PRG resulting from this calculation is 1168 ppm as shown above.

Page 20 of 20

i .1

South t Street _ Original

Hi 201

_ Former Wool Storage Building

ffc-107!^, Bemste:,,

| llHr Salvage vard

-i-r-i-4-rH-t-F-i-H-T _i_

1

inCD

CD i

13 :I Ro-110

^ r(C-108}

II

"X.

;ii3X»

South E Street

__ Vcsu-L^ <■V

\ >--A

L£f5e ! ,-^rc-Truck~j*/ — Scale \ 1 i

j ' /4RC-100j

Former Quonset Hut

Smai!Truck-Scale

i X

rqc-104^. x

FormerGasolineStation

iRC-102U.

! :?c-io3 _x_

sflC-ioilFC-iesx.,

y

011^

114:

-1—1- I I-s

4 a

-i—I

EGEMDSoil Sample Location

Former Buildings/Features

Former Railroad Tracks

Railroad Tracks

/■“s *v■ "A

O'.

I < ii ii ! ; CO i

hssiaence

\ A-

Scurce: Manaska County Assessors Office Rat Mao. 1383.

i- i i

Bernstein Salvage Site

Oskaloosa, low?

i i! II

i DD: S07-SSQ3-G01 PAN: 1135S8SFXX

Prepared by Brooke Barror Aprii 13SS

i

: II 1! I

SCALE (feet)

ecoicgy and environment, inc.j j

10MAPCCR

:igure f: Currant Site and Soli Sample Locations Mac

IDPH Bernstein Salvage Site Print Date: 01/25/2000

Table A-l Summary of Calculation Results for Residential Land Uses (RME1)

Bernstein Salvage Site, Oskaloosa, Iowa

Chemicals RfD SF ABS

PRCnc

THI=0.1

prgk

TR=10'6

PRG

THI=0.1/TR=10'6

PRG

THI=0.1/TR=10’S

Unit mg/kg-day (mg/kg-day)'1 unitless mg/kg mg/kg mg/kg mg/kg

Antimony 4.00E-04 - 1.00E-02 1.07E+01 - 1.07E+01 1.07E+01

Arsenic 3.00E-04 1.50E+00 3.00E-02 7.65E+00 3.97E-01 3.97E-01 3.97E+00

4,4-DDT 5.00E-04 3.40E-01 3.00E-02 1.27E+01 1.75E+00 1.75E+00 1.27E+01

Dieldrin 5.00E-05 1.60E+01 1.00E-01 1.09E+00 3.19E-02 3.19E-02 3.19E-01

Heptachlor Epoxide 1.30E-05 9.10E+00 1.00E-01 2.84E-01 5.61 E-02 5.61 E-02 2.84E-01

Total PCBs - 2.00E+00 1.40E-01 2.36E-01 2.36E-01 2.36E+00

Benzo(a)anthracene - 7.30E-01 1.30E-01 - 6.59E-01 6.59E-01 6.59E+00

Benzo(a)pyrene - 7.30E+00 1.30E-01 - 6.59E-02 6.59E-02 6.59E-01

Benzo(b)fluoranthene 7.30E-01 1.30E-01 - 6.59E-01 6.59E-01 6.59E+00

Dibenz(ah)anthracene - 7.30E+00 1.30E-01 - 6.59E-02 6.59E-02 6.59E-01

lndeno(1,2,3-cd)pyrene - 7.30E-01 1.30E-01 6.59E-01 6.59E-01 6.59E+00

See attachment for specific formulas and parameter values used for residential land use expsoure scenario

Page 1


Table A-2 Summary of Calculation Results for Industrial/Commerical Land Uses (RME2)


Chemicals RfD SF ABSPRG„C

THI=0.1

PRGCC

TR=10"6

PRG

THI=0.1/TR=10'6

PRG

THI=0.1/TR=10‘i


Antimony 4.00E-04 - 1.00E-02 7.91E+01 7.91 E+01 7.91 E+01

Arsenic 3.00E-04 1.50E+00 3.00E-02 5.56E+01 3.46E+00 3.46E+00 3.46E+01

4,4-DDT 5.00E-04 3.40E-01 3.00E-02 9.27E+01 1.53E+01 1.53E+01 9.27E+01

Dieldrin 5.00E-05 1.60E+01 1.00E-01 7.62E+00 2.67E-01 2.67E-01 2.67E+00

Heptachior Epoxide 1.30E-05 9.10E+00 1.00E-01 1.98E+00 4.69E-01 4.69E-01 1.98E+00

Total PCBs - 2.00E+00 1.40E-01 1.94E+00 1.94E+00 1.94E+01

Benzo(a)anthracene - 7.30E-01 1.30E-01 - 5.43E+00 5.43E+00 5.43E+01

Benzo(a)pyrene - 7.30E+00 1.30E-01 - 5.43E-01 5.43E-01 5.43E+00

Benzo(b)fluoranthene - . 7.30E-01 1.30E-01 - 5.43E+00 5.43E+00 5.43E+01

Dibenz(ah)anthracene - 7.30E+00 1.30E-01 - 5.43E-01 5.43E-01 5.43E+00

lndeno(1,2,3-cd)pyrene - 7.30E-01 1.30E-01 - 5.43E+00 5.43E+00 5.43E+01

See attachment for specific formulas and parameter values used for industrial/commercial land use expsoure scenario

Page 2


Table A-3 Summary of Calculation Results for an Apartment Complex for Senior Citizens (RME3)



PRGnc

THI=0.I

PRGcc

TR=10'6

PRG

THI=0.1/TR=I0‘4

PRG

thh).i/tr=io'j


Antimony 4.00E-04 - 1.00E-02 2.87E+01 - 2.87E+01 2.87E+01

Arsenic 3.00E-04 1.50E+00 3.00E-02 2.08E+01 2.16E+00 2.16E+00 2.08E+01

4,4-DDT 5.00E-04 3.40E-01 3.00E-02 3.47E+01 9.53E+00 9.53E+00 3.47E+01


Heptachlor Epoxide 1.30E-05 9.10E+00 1.00E-01 8.10E-01 3.20E-01 3.20E-01 8.10E-01

Total PCBs - 2.00E+00 1.40E-01 1.37E+00 1.37E+00 1.37E+01


Benzo(a)pyrene - 7.30E+00 1.30E-01 - 3.82E-01 3.82E-01 3.82E+00

Benzo(b)fluoranthene - 7.30E-01 1.30E-01 - 3.82E+00 3.82E+00 3.82E+01



See attachment for specific formulas and parameter values used for an apartment complex for senior citizens land use expsoure scenario

Page 3

JDPH Bernstein Salvage Site Print Date: 01/25/2000

Table A-4 Summary of Calculation Results for a Fire Station (RME4)Bernstein Salvage Site, Oskaloosa, Iowa

Chemicals RfD SF ABSPRG„C

THI=0.1

PRGcc

TR=10-6

PRGTH1=0.1/TR=10"<

PRG

THT=0.1/TR=10"5

Unit mg/kg-day (mg/kg-day)-1 unitless mg/kg mg/kg mg/kg: ■. mg/kg

Antimony 4.00E-04 - 1.00E-02 1.00E+02 ' . - 1.00E+02 1.00E+02

Arsenic 3.00E-04 1.50E+00 3.00E-02 7.29E+01 4.93E+00 4.93E+00 4.93E+01

4,4-DDT 5.00E-04 3.40E-01 3.00E-02 1.22E+02 2.18E+01 2.18E+01 1.22E+02


Heptachlor Epoxide 1.30E-05 9.10E+00 1.00E-01 2.84E+00 7.30E-01 7.30E-01 2.84E+00

Total PCBs - 2.00E+00 1.40E-01 3.14E+00 3.14E+00 3.14E+01

Benzo(a)anthracene - 7.30E-01 1.30E-01 - 8.71 E+00 8.71 E+00 ' 8.71 E+01

Benzo(a)pyrene - 7.30E+00 1.30E-01 - 8.71 E-01 8.71 E-01 8.71 E+00

Benzo(b)fluoranthene - 7.30E-01 1.30E-01 - 8.71 E+00 8.71 E+00 8.71 E+01

Dibenz(ah)anthracene - 7.30E+00 1.30E-01 - 8.71 E-01 8.71 E-01 8.71 E+00

lndeno(1,2,3-cd)pyrene - 7.30E-01 1.30E-01 - 8.71 E+00 8.71 E+00 8.71 E+01

See attachment for specific formulas and parameter values used for a fire station expsoure scenario

Page 4


Table A-5 Summary of Calculation Results for a City Park Land Use (RME5)Bernstein Salvage Site, Oskaloosa, Iowa


PRG„C

THI=0.1

PRGcc

TR=10'<

PRG

THI=0.1/TR=10'6

PRG

THI=0.1/TR=10'5


Antimony 4.00E-04 - 1.00E-02 1.66E+01 - 1.66E+01 1.66E+01

Arsenic 3.00E-04 1.50E+00 3.00E-02 1.12E+01 1.74E+00 1.74E+00 1.12E+01

4,4-DDT 5.00E-04 3.40E-01 3.00E-02 1.87E+01 7.68E+00 7.68E+00 1.87E+01

Dieldrin 5.00E-05 1.60E+01 1.00E-01 ■1.39E+00 1.21E-01 1.21E-01 1.21E+00

Heptachlor Epoxide 1.30E-05 9.10E+00 1.00E-01 3.60E-01 2.13E-01 2.13E-01 3.60E-01

Total PCBs - 2.00E+00 1.40E-01 8.46E-01 8.46E-01 8.46E+0C


Benzo(a)pyrene - ' 7.30E+00 1.30E-01 - 2.39E-01 2.39E-01 2.39E+00

Benzo(b)fluoranthene - 7.30E-01 1.30E-01 - 2.39E+00 2.39E+00 2.39E+01



See attachment for specific formulas and parameter values used for a city park expsoure scenario

Page 5

f(bl

ood

3) A +> fc

4«J90uh

LEAD 0.99dRANGE&. E.AY'

0 to 84 Months

S^''( Cw (&*fa****^X

f(bl

ood

3t■o

APi

A%A0CiPi

Co■V0e9h

4 6 8 18 12 14 16 18 29 22 24

LEAD 8.99d

RANGE’JT-EAV!:':'

BLOOD LEAD CONCENTRATION (usr/db) 9 to 84 Months

PL* 3 - !"***Sr--/ L^A

8

IDPH Bernstein Salvage Site, Oskaloosa, IA Print Date:01/25/2000

Table A-6 Summary of Calculation Results for Industrial/Commercial Land Uses (RME2)Bernstein Salvage Site, Oskaloosa, IA

PbBfetal, o,95 GSDlb4\adult Rfetal/matemal PbBadutt0 BKSF AFS AT IRS eftL

LLU RBRG

pg/dL dimensionless

dimensionless

pg/dL pg/dL per pg/day

dimensionless

days g/day day/year pg/g (ppm)

10 1.8 0.9 1.7 0.4 0.12 365 0.05 250 153610 1.8 0.9 2.0 0.4 0.12 365 0.05 250 135410 1.8 0.9 2.2 0.4 0.12 365 0.05 250 1232

. 10 2.1 0.9 1.7 0.4 0.12 365 0.05 250 96010 2.1 0.9 2.0 0.4 0.12 365 0.05 250 77810 2.1 0.9 2.2 0.4 0.12 365 0.05 250 656

Exposure scenario considered: a 70kg child bearing age or pregnant female worker

works at the site 250 days per year for the continuing long term exposures.

Equations used for the above calculations:

RBRG = (PbBadultiCentrai - PbBa<Jult0)*AT/(BKSF*AFj*IRs*EFs)PbBaciU|tiCantrai — PbBfata|0 95/gsd1* i.adults Pfetal/matemal.

Where:PbBfefei. 0.9s=95th percentile blood lead concentration <pg/dL) among fetuses bom to women having exposures to the specified site soil concentration equal to or less than 1Qpg/dL.

GSD1'945!, #dUi=Estimated value of the individual geometric standard deviation of PbB among a population of pregnant women of child bearing age exposed to lead at the site.

Value of 1.8 is recommended for a more homogeneous population while 2.1 is recommended for a diverse, urban population.

RfetattiwormrConstant of proportionality between fetal blood lead concentration at birth and maternal blood concentration, 0.9 as the default value

PbBrt.. n=Tvpical blood lead concentration in women of child bearing age in the absence of exposures to lead-contaminated soil and dust from the site activity.

BKSF=Biokinetic slope factor relating increase in typical adult blood lead to average daily lead uptake (pg/dL blood lead increase per pg/day lead),0.4 default

AFt=Absolirte gastrointestinal absorption fraction for ingested lead in soil and lead in dust derived from soil, 0.12, default value.

AT-Averaging time, 365 days, default

IR,=lntake rate of soil, including soil contained in indoor dust, 50 mg/day .default.

EF,=Exposure frequency for contact with assessed soils and/or dust derived in part from these dust, 250 days/year .default.

RBRGsRisk based remediation goal for the arithmetic mean concentration of lead in soil (pg/g) at the site where exposure occurs.

Page 6

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