PUBLIC HEALTH ASSESSMENT

INTERNATIONAL SMELTING AND REFINING
TOOELE, TOOELE COUNTY, UTAH

FIGURES AND TABLES

Figure 1. Map of International Smelting and Refining (ISR) in Tooele County, Utah, Showing the Location of the ISR Site in Relationship to Surrounding Communities.

Figure 2. Map of Combined Reclaimed Areas, One Mile Buffer, and Demographics Information of International Smelting and Refining (ISR) and Carr Fork Operations in Tooele County.

Figure 3. Map Showing Locations of Source, Soil, Groundwater, and Surface Water Samples.

APPENDIX A: ACRONYMS AND TERMS DEFINED

Background Level:

The amount of a chemical that occurs naturally in a specific environment.

Cancer Classes:

Each health organizations has a separate method of cancer classification:
A	= Environmental Protection Agency (EPA) Classified as a Human Carcinogen.
B1	= EPA Classified as Probable Human Carcinogen (based on limited human and sufficient animal studies).
B2	= EPA Classified as Probable Human Carcinogen (based on inadequate human and sufficient animal studies).
C	= EPA Classified as a Possible Human Carcinogen (no human studies and limited animal studies).
1	= International Agency for Research on Cancer Classifies as "Carcinogenic to Humans" (sufficient human evidence).
2A	= IARC Classifies as "Probably Carcinogenic to Humans" (limited human evidence; sufficient evidence in animals).
2B	= IARC Classifies as "Possibly Carcinogenic to Humans" (limited human evidence; less than sufficient evidence in animals).
3	= IARC Classifies as "Not Classifiable."
4	= IARC Classifies as "Probably Not Carcinogenic to Humans."
1	= National Toxicology Program (NTP) Classifies as "Known Human Carcinogen."
2	= NTP Classifies as "Reasonably anticipated to be a carcinogen."
3	= NTP Classifies as "Not Classified."

Comparison Values:

Media-specific concentrations that are used to select environmental contaminants for further evaluation in public health assessments. These values are not valid for other types of media, nor do concentrations above these values indicate that a health risk actually exists.

Examples of Comparison Values

EMEG	= Environmental Media Evaluation Guide.
RMEG	= Reference Dose Media Evaluation Guide.
CREG	= Cancer Risk Evaluation Guide for 1x10-6 excess cancer risk.

Completed Exposure Pathway:

A way in which people can be exposed to a contaminant associated with a site. An exposure pathway is a description of the way a chemical moves from a source to where people can come into contact with it. A completed exposure pathway has all of the 5 following elements:

1. a source of contamination
2. transport through environmental medium
3. a point of exposure
4. a route of human exposure
5. an exposed population

CREG:

Cancer Risk Evaluation Guides are based on a contaminant concentration estimated to increase the cancer risk in a population by one individual in one million people over a lifetime exposure.

EMEG:

Environmental Media Evaluation Guides are media-specific comparison values used to select contaminants of concern at hazardous waste sites. EMEGs are derived from Minimal Risk Levels (MRLs), developed by the Agency for Toxic Substances and Disease Registry (ATSDR), and are an estimate of human exposure to a compound that is not expected to cause noncancerous health effects at that level for a specified period. They are intended to protect the most sensitive individuals (i.e. children). MRLs are guidelines and are not used to predict adverse health affects. MRLs do not take into account carcinogenic effects, chemical interactions, or multiple routes of exposure.

EPA:

The U.S. Environmental Protection Agency (EPA) is the federal agency that develops and enforces environmental laws to protect the environmental and public health.

LOAEL:

The Lowest Observable Adverse Effect Level (LOAEL) is the lowest exposure level of a chemical that produces significant increases in frequency or severity of adverse effects.

MRL:

A Minimal Risk Level (MRL) is defined as an estimate of daily human exposure to a chemical that is likely to be without an appreciable risk of deleterious non-cancer health effects over a specified duration of exposure. Thus, MRLs provide a measure of the toxicity of a chemical.

NOAEL:

The No Observable Adverse Effect Level (NOAEL) is the exposure level of chemical that produces no significant increases in frequency or severity of adverse effects. Effects may be produced at this dose, but they are not considered to be adverse.

NPL site:

The National Priorities List (NPL) is a list published by EPA ranking all the Superfund sites. Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), a federal law enacted in 1980. This law was preauthorized in 1986 as the Superfund Amendments and Reauthorization Act. CERCLA enables EPA to respond to hazardous waste sites that threaten public health and the environment. A site must be added to the NPL site list before remediation can begin under Superfund.

Potential Exposure Pathway:

A possible way in which people can be exposed to a contaminant associated with a site. An Exposure pathway is a description of the way a chemical moves from a source to where people can come into contact with it. A potential exposure pathway has 4 of the 5 following elements:

1. a source of contamination
2. transport through environmental medium
3. a point of exposure
4. a route of human exposure
5. an exposed population

Public Health Hazard:

The category ATSDR assigns to sites that pose a health hazard to the public as the result of long-term exposures to hazardous substances. See "Public Health Hazard Categories".

Public Health Hazard Categories:

Categories defined by ATSDR and used in Public Health Assessments that assess if people could be harmed by conditions present at a site. One of the following categories is assigned to each site:

• Urgent Public Health Hazard
• Public Health Hazard
• Indeterminant Public Health Hazard
• No apparent health hazard
• No Pubic Health Hazard

APPENDIX B: CALCULATIONS

(A) Calculating Exposure Dose (ED) in soil [ATSDR 1992]:

ED = { C x IR x EF) / BW }

(A.1) Calculating Exposure Factor (EF) [ATSDR 1992]:

EF = { (#days/week) x (#weeks/year) x (ED) / (ET) x (365days/year) }

(i) On-site adult exposure : In estimating EF for adults on-site, we assume an adult visits the site once a month for 30 years and lives for 70 years [ATSDR 1992].

We can then use EF = 0.015 and substitute it into the ED equation given above to estimate the exposure dose to a given contaminant at the maximum level detected.

(ii) In estimating EF for adults and children off-site, we assume adults are at work outside the home for hours/day and 40 hours/week, children are at school for hours/day and 40 hours/week, and that both adults and children are in the vicinity of the home for the weekend.

Since the academic year lasts 9 months, that is equivalent to 3/4 of a full calendar year or 39 weeks.
During the academic year, children are at home for 128 x 39 = 4992 hours = 208 days

During the summer months, children may be home 24 hours per day for the remaining 13 weeks; therefore, children are at home for 24hrs/day x 7 days/wk x 13wks = 2184 hours = 91 days
The total number of days / year that children are home is 208 + 91 = 299
Therefore children are at home 299 days in 52 weeks = 299/52 = 5.75 days/wk.

We can then use these EFs and substitute it into the ED equation given above to estimate the exposure dose to a given contaminant.

(B) Comparison Value Calculations for Soil [ATSDR 1992]:

EMEG = MRL x BW / IR

RMEG = R_fD x BW / IR

CREG = 10E^-6 x BW / IR x OSF

(B.1) Calculating RMEG for Mercury in soil:

RfD	= 1E-4 (ppm)/day Of the mercury compounds, "methylmercury is the compound of greatest concern for human health" [EPA 1999b]
RMEGadult	= RfD (BW)/IR
	= 1 x 10-4 mg methylmercury/kg/day(70 kg)/100 mg soil/day)
	= 7 x 10-5 (mg methylmercury/day)/(mg soil/day)
	= 70 (mg methylmercury/day)/(kg soil/day)
	= 70 ppm
RMEGchild	= RfD (BW)/IR
	= 1 x10-4mg methylmercury/kg/day(10 kg)/200 mg soil/day)
	= 5 x 10-6 (mg methylmercury/day)/(mg soil/day)
	= 5 (mg methylmercury/day)/(kg soil/day)
	= 5 ppm

(B.2) Calculating RMEG for Copper in soil:

RfD	= 0.029 (ppm)/day based on the National Academy of Sciences 2-3 mg Copper safe dose for a 70 kg adult [NAS 1980].
RMEGadult	= RfD (BW)/IR
	= (0.029 mg copper/kg/day)(70kg)/100 mg soil/day)
	= 0.02 (mg copper/day)/(mg soil/day)
	= 20,300 (mg copper/day)/(kg soil/day)
	= 20,300 ppm

APPENDIX C: PUBLIC COMMENTS TO PUBLIC HEALTH ASSESSMENT
(Release for Public Comment)

On August 3, 2000, EEP participated in a public availability session to address any health related questions from residents of Lincoln and Tooele. Representatives from the Tooele County Health Department, UDEQ, EPA, and the site owners and contractors were available at the session to answer questions concerning remediation activities. Following is a summary of the public comments and responses regarding health effects and the public health assessment document.

2. Comment: There are a lot of us in Carr Fork that are concerned about exposure to our children, but we are hesitant to get them tested because of the bad experiences we've heard from other people who have had their kids tested. How will you be testing for blood lead ?

UDOH Response: The blood lead testing will be performed by the "finger-prick" method, where a small amount of blood is collected by pricking the finger. It is a quick screening tool that most children tolerate very well. Drawing a sample from the arm vein will only be necessary if the blood lead levels appear high during the screening procedure. The blood lead testing is available at the Tooele County Health Department by appointment.

3. Comment: We just moved into the Carr Fork subdivision recently. Should we be concerned about our health ?

UDOH Response: For adults, adverse health effects are not expected from exposure to contaminants associated with the ISR site. The estimated exposure doses to adults from contaminants in on- and off-site soil are below the ATSDR comparison values, and contaminants have not been found in your drinking water. However, we recommend that you minimize exposure by avoiding recreational use of the ISR site and by taking dust control measures in your homes.

4. Comment: Can lead be transferred to my baby through breast-feeding? How old does a baby need to be to be tested for blood lead?

UDOH Response: Lead can be found in breast-milk from mothers exposed to lead. The levels of lead in breast-milk vary depending on the mother's exposure and diet. For blood lead testing, we recommend that children are between the ages of 6 months and 6 years.

5. Comment: I was a former employee at the ISR site, and I know they used mercury in the process. Is mercury a concern?

UDOH Response: Mercury is not a chemical of concern for the ISR site. The levels of mercury detected in the source and in on- and off-site soil samples were below the ATSDR comparison values for children and adult exposures.

6. Comment: We are considering purchasing land in Lincoln. How can we find out if it is contaminated ? [This question was posed to a representative of the Utah Department of Environmental Quality (UDEQ) present at the public availability session.]

UDEQ Response: If you have concerns about contaminants in your soil, you may contact UDEQ. Although UDEQ cannot provide testing, they can direct you to laboratories which provide that service.

7. Comment: How can I keep informed about the ISR site ?

UDOH Response: We utilize several approaches to ensure that residents are kept informed about health-related activities regarding the ISR site.

(A) EEP submits legal notices, and/or advertisements, and/or press releases to local media to notify communities of any upcoming public availability sessions or document releases.

(B) EEP coordinates all health-related activities through the Tooele County Health Department.

(C) All EEP documents are available at both the Tooele County Health Department and the Tooele City Library during the public comment period.

(D) Residents expressing an interest in receiving updates by mail may sign up on the EEP mailing list for this site.

(E) Residents can call EEP of the Utah Department of Health if they have any further questions. The contact information is in the Foreword of the public comment document.

8. Comment: In most cases, it is inappropriate to use data collected in 1985 prior to reclamation, because it likely does not represent current site conditions.

UDOH Response: Data collected during investigations prior to reclamation are included in the document to provide a comprehensive summary of investigations at the ISR site. In this public health assessment, evaluation of health effects due to contaminants associated with the ISR site rely on data from the most recent investigation, the 1996 Expanded Site Inspection by UDEQ.

9. Comment: [Summary, Paragraph 1, line 4] The current RI/FS is intended to ascertain the effectiveness of the reclamation activities, and to determine if there are exposed elevated levels. It is premature to suggest at this time that the contaminant levels are "elevated" or that reclamation activities were not effective.

UDOH Response: The 1996 Expanded Site Inspection by UDEQ demonstrated that contaminant levels were elevated compared to background levels. In tailings sample, SC-13, the level of arsenic detected (5,420 mg/kg) was over 360 times the background level (14.9 mg/kg). In the same tailings sample, the concentration of lead detected (61,300 mg/kg) was 480 times that of the background level for lead (127.5 mg/kg).

Further, some contaminant levels reported in the 1996 UDEQ investigation also exceeded comparison values developed by the Agency for Toxic Substances and Disease Registry (ATSDR). Comparison values are screening guidelines used to determine which contaminants (if any) require further evaluation with respect to exposure and possible health effects. Levels of exposure above these guidelines will only cause adverse health effects if persons are actually exposed and if the exposure is at a sufficient dose for adverse effects to occur.

10. Comment: [Summary, Paragraph 2, line 1] Normal waste management practices in the past may be viewed as substandard by today's standards; however, these were not necessarily poor practices at the time. This subjective statement is unsupported and misplaced and the report should stay with more objective descriptions, such as "historic waste management practices."

UDOH Response: The statement has been modified to read, "Contamination in the surrounding area has been attributed to historic stack emissions and waste management practices."

11. Comment: [Summary, Paragraph 2, line 5] What evidence exists to support this statement? A screening level to with which to compare site data has not been established for this site. Although one residence sample has a concentration of lead of 1,040 ppm; the majority of residences sampled had lead concentrations that were below 500 ppm.

UDOH Response: The 1996 Expanded Site Inspection by UDEQ demonstrated that contaminant levels were elevated compared to background levels. Levels of arsenic and lead exceeded background levels in 9 out of 10 soil samples collected from Lincoln residences. Soil samples from 8 of the 10 homes sampled contained levels of arsenic that exceed the ATSDR comparison value for arsenic. Because ATSDR has not yet established a comparison value for lead, for this public health assessment, we relied on the screening value established by the Environmental Protection Agency (EPA) for permissible children's exposure to lead in soil, 400 ppm. Using this guideline, the levels of lead detected in 4 of the 10 residences would be considered elevated.

12. Comment: [Summary, Paragraph 2, line 6] This statement is completely unsupported and should be deleted from the Draft Report. Only one of the surface water samples collected by the DERR in 1995 had a lead concentration exceeding the drinking water standard: SW07. It is unknown where this sample was even collected, and important information concerning how it was collected is missing. Moreover, the mapped location of this sample is nowhere near surface water, and is not influenced by any surface water from the site. No groundwater sample contained lead in excess of the drinking water standard. The analytical results for sample AC-GW-02, which was listed in Table 5 as evidence of groundwater impact was written in error. The actual concentration is 4 ppb, and so is not above the MCL.

UDOH Response: The missing information regarding SW-07 has been acknowledged in the final report and the errors in Table 5 were corrected.

Investigations by UDEQ (1984 and 1996), EPA (1985), and AERL's consultants (1986) all reported that some contaminants were present in surface water and/or groundwater at levels that exceeded background levels and, in some cases, EPA's maximum contaminant levels (MCLs).

13. Comment: [Page 4, Paragraph 3, line 8] There is no reference supporting this statement; nor is AERL aware of any evidence supporting this statement in either historic data or based upon current conditions at the site. It seems unlikely that the groundwater surface would drop over 500 feet vertically over a distance of 1,200 feet horizontally. If the statement above is referring to the personal communication (Lips, 1995) statement reported by the DERR that perched groundwater was encountered while excavating the repository trench, no evidence from the people that were working at the site support this statement. It may be that some of the shallow subsurface soils were wet, but this would not necessarily represent a perched groundwater zone. It most certainly would not be connected with the primary groundwater aquifer, which is found at depths of hundreds of feet below the ground surface at the site.

UDOH Response: Reference 12 was added at the end of the paragraph. The statement in question was obtained from the 1984 Site Inspection by the Utah Division of Environmental Health (now UDEQ). On page 2, section II.B of the report, it states, "Beneath the tailings pond, the water table is located at a depth greater than 500 feet. Four-hundred yards to the south-east it is located at the ground surface."

14. Comment: [Page 4, Paragraph 4, Line 2] What evidence or data was used to support this statement that contaminant levels continue to be elevated in the reclaimed areas? This is one of the purposes of the RI.

UDOH Response: The 1996 Expanded Site Inspection by UDEQ demonstrated that some contaminant levels were elevated compared to background levels. Some contaminants were detected at levels that also exceeded ATSDR comparison values and, therefore, warranted further evaluation. The map (Figure 2) generated in this document is used only to more accurately estimate the populations which may be impacted by contaminants associated with the ISR site. The map is not to be used to determine clean-up boundaries or for any other aspect of the clean-up process.

15. Comment: [Page 5, Paragraph 5, Line 6] The site is intended to be a wildlife habitat, with a conservation easement granted to the Division of Wildlife Resources. The fences and signs are intended to control inappropriate human access.

UDOH Response: The statement was included to acknowledge that there is free access for wildlife.

16. Comment: [Page 5, Paragraph 6, Line 3] The two projects were reclaimed together and reclamation efforts were done in areas which were shown in the initial site investigation to merit reclamation. Also, the reclamation was performed for AERL in a manner which went above and beyond the DOGM regulations and was overseen and approved by DOGM.

UDOH Response: The statement was taken directly from page 5, paragraph 3 of the 1996 Expanded Site Inspection by UDEQ. The statement makes no inference that reclamation did not meet nor exceed Division of Oil, Gas, and Mining (DOGM) regulations.

17. Comment: [Page 6, Paragraph 2, Line 8] What "dump area" is being referred to? If this statement is referring to the top surface of the slag pile, it was covered with soil and vegetation. All dumps (landfills) on site were revegetated.

UDOH Response: This statement was taken directly from page 12, paragraph 4 of the EPA Hazard Ranking System (HRS) document for this site. The reference given for this information was a study by AERL's consultants, the 1986 JBR Consultants Group Reclamation/Stabilization Plan of March 3, 1986, plate 6-3.

18. Comment: [Page 6, Paragraph 2, Line 9-11] This opinion is completely unsupported and inappropriate for a report such as the draft report. The overall effectiveness of the reclamation effort is to be evaluated during the RI. In fact, the vegetation at the site is growing vigorously when compared to other similar foothills areas around Tooele. This site is maintained through a maintenance program.

UDOH Response: Off-site migration of contaminants was documented in both the EPA HRS document for the site and in the 1996 Expanded Site Inspection by UDEQ. In the latter report (page 12, section 5.1), it states, "The native soil cover has not supported vigorous plant growth and erosion is occurring in several areas." ATSDR prepares supplements to public health assessment documents every 5 years to account for data and information that becomes available subsequent to the release of the final report. Any new findings in the RI/FS will be included in the impending supplement for this public health assessment.

19. Comment: [Page 6, Paragraph 3, line 3] Arsenic and lead were elevated in several of the source samples, but cadmium was not elevated, based on comparison with other soils from the region. Zinc was not tested in the solid samples.

UDOH Response: This statement was obtained from the 1984 Site Inspection by the Utah State Division of Environmental Health. Cadmium was detected in tailings at 48 ppm, and zinc was detected in slag at 600,000 ppm. The background levels for cadmium and zinc are 1.46 ppm and 206 ppm, respectively.

In addition, the 2000 AERL Remedial Investigation/Feasibility Study Work Plan for the site (ARCO 2000, page 20, paragraph 4) states, "Samples collected from surface water, tailings, slag, and spring water were reported to contain elevated levels of arsenic, cadmium, and lead."

20. Comment: [Page 6, Paragraph 3, line 5] Of the samples collected from Pine Creek, only one exceeded drinking water standards for lead (0.375 mg/L vs. the MCL of 0.015 mg/L). Neither the arsenic nor cadmium MCL was exceeded.

UDOH Response: This statement was obtained from the 1984 Site Inspection by the Utah State Division of Environmental Health. Lead was detected at 0.765 ppm compared to a background level of 0.37 ppm.

In addition, the 2000 AERL Remedial Investigation/Feasibility Study (RI/FS) Work Plan for the site (ARCO 2000, page 20, paragraph 4) states, "Samples collected from surface water, tailings, slag, and spring water were reported to contain elevated levels of arsenic, cadmium, and lead."

21. Comment: [Page 6, Paragraph 3, line 6-7] While the concentrations of lead and cadmium did exceed drinking water standards (0.11 mg/L lead vs 0.015 mg/L mg/L lead MCL and 0.02 mg/L cadmium 0.005 mg/L cadmium MCL), these levels probably would not be considered "high." Also, this spring was seen in the late 1980's, but has dried up since then. Based on site visits occurring in all seasons throughout the 1990's, this seep no longer appears to flow.

UDOH Response: Statement was modified and now reads, "Groundwater samples collected from springs surfacing at the edge of a slag pile was contaminated with levels of lead and cadmium that exceeded background levels." The information provided in the Discussion section is included in the document to provide a comprehensive summary of investigations at the ISR site. Evaluation of health effects from contaminants associated with ISR are performed using data from the most recent investigation, the 1996 Expanded Site Inspection by UDEQ.

22. Comment: [Page 6, Paragraph 3, lines 8-10] The site's geographic setting suggests that there is little chance of a migration route for contaminants from the site to Middle Canyon, located approximately 2.5 miles to the southwest.

UDOH Response: This statement was obtained from the 1984 Site Inspection by the Utah State Division fo Environmental Health. In this report, Part 3, section II states "Middle Canyon soil contaminant due to fallout of wind-blown tailings was documented in the site inspection."

23. Comment: [Page 6, Paragraph 4, lines 10-11] The phrasing of this sentence taken with the preceding sentence indicates that the UDEQ found groundwater contamination in a down-gradient well, when in fact UDEQ only found lead and cadmium in the seep emanating from the base of the slag pile. Incidentally, that seep dried up and has not flowed since the early 1990's.

UDOH Response: The statements have been modified to read "Because of an unsuccessful attempt to reach groundwater at a down-gradient well, only an up-gradient groundwater sample was collected and potential contamination of groundwater wells could not be evaluated."

The results of the 1985 EPA study were included in the document to provide a comprehensive summary of investigations at the ISR site and are not used to depict present conditions nor to evaluate health effects. This public health assessment relies on data obtained during the 1996 Expanded Site Inspection by UDEQ, which did not include any sampling at the seep.

24. Comment: [Page 7, Paragraph 1, line 3] Samples were taken up to 8,000 feet to the west, 7,000 feet to the east, 6,000 feet to the north, and 6,000 feet to the south of the center of the site. Elevated lead levels were not found in the north or south transect samples; elevated lead levels (up to 2,000 ppm) dropped off beyond 4,000 feet along the east and west transects.

UDOH Response: The statement has been modified to read, "Elevated levels of lead and arsenic were found in soil samples collected within a 4,000 foot radius from the center of the former smelter location." Although levels of arsenic and lead decreased significantly beyond the 4,000 foot radius, note that samples collected up to 7,000 feet on the east transect, and up to 6,000 feet on the north and south transects exceeded the Salt City/Wasatch Front background values for arsenic and lead.

25. Comment: [Page 7, Paragraph 1, line 6] Only lead was found above drinking water standards in two surface water samples (one of these was at the mouth of the Pine Canyon tunnel, approximately 3 miles up-gradient of the site). Lead was found exceeding drinking water standards in 4 down-gradient wells in September 1985; however, when these wells were resampled in November 1985, the lead concentrations were non-detectable.

UDOH Response: The statement has been corrected and modified to read, "Levels of lead exceeded EPA maximum contaminant levels (MCLs) in two surface water samples and all 5 groundwater samples collected. Cadmium exceeded the EPA MCL in one surface water sample." These exceedances were documented in the 1985 JBR investigation and also in the 2000 AERL RI/FS Work Plan (ARCO 2000).

The 5 groundwater samples collected in September 1985 by JBR contained levels between 117-470 ppb of lead, all exceeding the EPA MCL of 15 ppb. Although lead was undetected in the November 1985 resampling by JBR, neither JBR nor AERL has provided a definitive explanation as to the discrepancy in the results. Because a public health assessment relies on the most current data, the results of the 1985 JBR studies are not considered in the evaluation of health effects. The information is included only to provide a comprehensive summary of the investigations that have been conducted at the ISR site.

26. Comment: [Page 7, Paragraph 2, line 7] There is no evidence that off-site contamination continues to occur either from any soil, groundwater, or surface water data by observation. The soil sample with elevated lead collected in Lincoln offers evidence that off-site migration occurred sometime in the past, possibly as a result of a homeowner importing fill for construction.

UDOH Response: Statement was modified to read, "Soil, surface water, and groundwater samples collected on and off site contained elevated levels of several metals, indicating that off-site migration of contaminants had occurred."

The levels of lead detected in 4 of the 10 Lincoln residences sampled were elevated compared to the EPA guideline for permissible exposure to lead in soil for children. It is unlikely that the homeowners of those 4 residences had all imported fill for construction. For this reason, the elevated levels of lead are assumed, at this time, to be associated with the ISR site and exposure by soil ingestion and inhalation were evaluated, and the results of that evaluation are presented in this public health assessment.

27. Comment: [Page 7, Paragraph 2, line 9] Due to the high level of historic mining activity in the Tooele County/Tooele area, perhaps it would be more appropriate to compare the concentrations to background levels in the Oquirrh mountain area.

UDOH Response: Background values for the Salt lake County/Wasatch front area were calculated from 18 different CERCLA sites along the Wasatch Front. These values were used in the 1996 UDEQ Analytical Results Report and the EPA HRS Documentation Record. UDOH is not aware of any available data on background levels for inorganic contaminants in the Oquirrh mountain area.

28. Comment: [Table 1-5] Data presented in the tables were assumed to be from various past studies performed over a number of years for many different reasons. Given the limited amount of time to review this draft report, AERL was unable to fully check all data and their references for accuracy in translation to the draft report, for relevance, or for determining if the data was of a suitable quality to even be considered for use. However, based on a spot check of the information presented in the tables, it appears there are numerous concerns as to translation errors and particularly inappropriate use of data or use of data of questionable quality. The following are two examples of AERL's concerns regarding how data was used in this draft report:

A) Table 5 shows the results from the DERR groundwater samples from 1995. This table lists the results for AC-GW-02 as 43 ppb. This value should read 4 ppb. The drinking water standard is 0.015 ppm; however, the table indicates that the drinking water standard for lead is 0.015 ppb. Therefore, Table 5 shows that all the samples have elevated levels of lead exceeding the standard, then in fact, none exceed the standard.

B) The report uses the DERR results of surface water sample SW-07 as evidence of off-site migration of surface water contaminants and stream sediments. However, the draft report fails to acknowledge that the location of SW-07 was never discovered. The location shown on the DERR map is not even on the Pine Creek drainage (or any drainage, for that matter). Making conclusions based on data whose location cannot even be found is inappropriate.

UDOH Response: Values in Table 5 were corrected, and the missing information on sample AC-SW-07 was acknowledged in the text.

The data from Tables 1-5 were derived only from the 1996 UDEQ Expanded Site Investigation report. Despite the errors in Table 5 and the missing information on SW-07, there is sufficient evidence from previous investigations to suggest release of some contaminants to surface water and groundwater.

29. Comment: [Tables 1-5, and use of data as summarized in pages 7 through 17] AERL performed a thorough review and critique of the various reports referenced in this draft in 1999. This review was provided to EPA in the form of comments upon EPA's proposed listing of the IS&R site on the NPL. AERL's comments are contained in Attachment 2. AERL's comments in Attachment 2 should be seriously considered before UDEQ finalizes the draft report due to the number of problems related to the past studies and the use of these studies as a basis for the draft report.

UDOH Response: ATSDR prepares supplements to public health assessment documents every 5 years to account for data and information that become available subsequent to the release of the final report.

30. Comment: In the text, "recent" information was referenced yet the only document information is from the 1990 census. Only documented information should be used in such a report.

UDOH Response: In the "Demographics and Land Use" section of the document, population estimates for 1999 were given along with the corresponding reference for the data.

31. Comment: The discussion of surface water in Pine Creek as well as a poster presented in the public meeting in Tooele on August 3 indicate the creek was dry at and below the ISR site in February 2000 and that visitation to the site is occasional thus reducing any potential exposure to the public from surface-water runoff from the site. Discussions and a site visit with representatives from your office on August 3 revealed that observations of a dry Pine Canyon Creek in February were in error and that the creek was flowing past the ISR site at the time of the visit on August 3. The February observations were not made in the Pine Canyon Creek channel.

UDOH Response: The on-site visit on August 3, 2000, did in fact, reveal that Pine Creek was flowing and attendees at the meeting were informed of the error on our poster. Since the erroneous observation was not discussed in the text, no changes were needed.

32. Comment: In the spring of 1995, I observed Pine Canyon Creek flowing through the Country Lane Estates subdivision and traveling north along Droubay Road. Thus, any contaminated surface water leaving the site may pose a health risk for people in the Country Lane Estates subdivision who come in contact with the stream during those wet years in addition to contaminating ground-water in the area.

UDOH Response: Although Pine Creek is accessible to on-site trespassers and off-site residents and visitors, the potential for exposure to contaminants is low because it is not a source of drinking water.

33. Comment: [page 10] The discussion states "Limited and conflicting groundwater sampling data exist from the ISR vicinity." The discussion centers on UDEQ reports of wells in the town of Erda being contaminated with nitrates while sampling of water wells on and off site in 1985 and 1995 did not show high nitrate concentrations. The data is not conflicting. Tooele County and the U.S. Geological Survey, with the help of local drillers identified high nitrate, sulfate, and dissolved solids concentrations in the upper 150 feet of the saturated basin fill in Erda in 1994. Since that time, efforts have been made to provide guidance to local well owners in order to avoid completing wells in contaminated zones. Some existing wells with high nitrate concentrations were deepened, and new wells have been monitored during drilling to assure that the completed wells were below the zone of high nitrate concentrations. Water-quality data collected during the drilling of wells show contamination in the upper 150 feet of saturated basin fill, but for obvious reasons, drinking water wells are not being completed in those zones. Therefore, completed drinking water wells are poor sampling locations for identifying contamination. In 1999, Tooele County and the U.S. Geological Survey drilled and completed two triple-completion wells to monitor the spatial and temporal distribution of contaminants in the saturated basin fill.

UDOH Response: The statement has been modified to read, "Limited groundwater sampling data exist from the ISR vicinity." Statements regarding the depth of groundwater sampling have also been added to the discussion to clarify the extent of groundwater contamination.

34. Comment: Water sample from one of the U.S. Geological Survey monitoring wells in the Country Lane Estates subdivision were analyzed for arsenic. The concentration of arsenic in the upper most screened interval was determined to be 206 µg/L in one sample and 140 µg/l in another sample. The high concentration of arsenic indicates a probable mining-related release. Nitrate concentrations in 2 out of the 3 zones sampled exceeded the drinking water standard of 10 mg/L. Although the high arsenic and nitrate concentrations have only been identified in the upper 150 feet of saturated basin fill deposits, it is likely that the contaminated water will migrate downward and eventually infiltrate the zones currently being pumped for drinking water by private well owners and public supply wells in the Erda and Stansbury Park areas. This office has collected a large number of samples and is currently working on a report documenting the high nitrate concentrations in the Erda area.

UDOH Response: Arsenic is a contaminant of concern in the groundwater exposure pathway, and health effects are discussed in the Toxicologic Evaluation section of the PHA. ATSDR prepares supplements to public health assessment documents every 5 years to account for data and information that become available subsequent to the release of the final report. Any new findings in the upcoming USGS report on Erda groundwater will be included in the impending supplement for this public health assessment.

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