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PUBLIC HEALTH ASSESSMENT

INTERNATIONAL SMELTING AND REFINING
TOOELE, TOOELE COUNTY, UTAH


SUMMARY

The International Smelting and Refining (ISR) site is a reclaimed mine, mill, and smelter property located approximately 2.5 miles northeast of Tooele in Tooele County, Utah. Copper and lead smelting activities conducted between 1910 and 1972 resulted in elevated levels of arsenic, cadmium, and lead in soil. Despite reclamation efforts in 1986, ISR contaminant levels remained elevated, and the site was proposed for the National Priorities List on April 23, 1999. In response, the Agency for Toxic Substances and Disease Registry (ATSDR) requested that the Environmental Epidemiology Program (EEP) of the Utah Department of Health conduct this public health assessment.

Contamination in the surrounding area has been attributed to historic stack emissions and waste management practices. The Utah Department of Environmental Quality, the United States Environmental Protection Agency, and consultants contracted by the owners of ISR conducted investigations that indicated the presence of elevated levels of several contaminants in on- and off-site soil, smelter waste, tailings, and slag. Limited evidence indicates some contaminants have been released to surface water and groundwater.

Three completed exposure pathways by which people have been exposed to contaminants from the ISR site include: (1) ingesting or inhaling contaminated smelter waste, tailings, and slag particles; (2) ingesting or inhaling contaminated soils on site; and (3) ingesting or inhaling contaminated soils off site. The estimated exposure doses for on-site adult visitors and off-site adult residents do not exceed the ATSDR Minimal Risk Levels (MRLs); therefore, adult exposures are not expected to result in adverse health effects. However, the estimated exposure dose for children living near the ISR site exceeds the ATSDR MRLs and, therefore, that exposure pathway is evaluated further.

Compared to adults, children are at increased risk from exposure to environmental contaminants; children often play outside and have behaviors that make them more likely to come in contact with dust and soil. Also, because children's bodies are still developing, children can sustain permanent damage if toxic exposures occur during critical growth stages. Exposures to high levels of lead and arsenic can cause damage to blood cells, kidneys, and the gastrointestinal, reproductive, and nervous systems. Both lead and arsenic are capable of crossing the placental barrier and causing harm to the fetus. Kidney, lung, and intestinal damage are seen in children exposed to high levels of cadmium. Evidence indicates that arsenic is a human carcinogen. Cadmium and certain forms of lead are classified as probable human carcinogens, based on animal studies.

Although the estimated exposure dose for children for arsenic and cadmium exceeds the corresponding ATSDR MRLs, further evaluation of available human studies indicates that these levels are not expected to produce adverse health effects. Because no comparable human studies are available for lead, and because children are particularly susceptible to the effects of lead, the estimated exposure dose is considered sufficient to possibly produce adverse health effects.

The EEP public health action plan, designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment from the ISR site, consists of the following past and future actions:

EEP, in coordination with other local and state agencies, conducted a public availability session for residents of Lincoln and the Carr Fork subdivision in Tooele City. At the session, EEP addressed health concerns related to the ISR site, provided information on the contaminants, and outlined measures to reduce exposure.

The Tooele County Health Department (TCHD) offered free blood lead testing for children aged 6 months to 6 years of age living in the communities of Lincoln and the Carr Fork subdivision in Tooele during the year 2000.

EEP will provide environmental health education materials to residents of Lincoln and the Carr Fork subdivision in Tooele through the Tooele County Health Department (TCHD). The materials will provide information on lead poisoning prevention and will outline dust control methods.

EEP continues to monitor the Utah Blood Lead Registry for children with elevated blood lead levels in areas near the site.

EEP provided the Utah Department of Environmental Quality (UDEQ), the United States Environmental Protection Agency (EPA), and the site owner with copies of this Public Health Assessment so that they are aware of our recommendations.

TCHD and EEP will continue to work with agencies such as UDEQ and EPA to address the public health issues related to the ISR site.


PURPOSE AND HEALTH ISSUES

The Agency for Toxic Substances and Disease Registry (ATSDR) requested that the Environmental Epidemiology Program (EEP) of the Utah Department of Health conduct this public health assessment to identify any public health hazards posed by the International Smelting and Refining (ISR) site. For this document, EEP evaluated the most recent analytical results for mine waste, soil, surface water, and groundwater samples to determine the contaminants of concern. EEP evaluated exposure pathways identified for the contaminants and estimated exposure doses for target populations. Ultimately, this assessment provides conclusions on the public health issues relevant to the ISR site and makes recommendations to protect the health of residents in the area.

The 1986 Superfund Amendments and Reauthorization Act to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 directs ATSDR to perform specific public health activities associated with actual or potential exposures to hazardous substances released into the environment. Among those activities, ATSDR was mandated to perform a public health assessment for each facility or site listed or proposed to be listed on the National Priorities List within one year of the listing. In addition, ATSDR may conduct a public health assessment for a particular facility or release when petitioned by a person or group of persons. ISR was proposed for the National Priorities List (NPL) on April 23, 1999 [EPA 1999a].


BACKGROUND

Site Description and History

ISR began operating a copper smelter in 1910, added a lead smelter in 1912, and was acquired by Anaconda Copper in 1915. Subsequently, a lead-zinc sulfide flotation mill (1924) and a slag treatment plant (1941) were added to the facility. The site offered proximity to ore supplies, water, and a concurrently constructed railroad, the Tooele Valley Railroad(1).

The site's sloping terrain facilitated in feeding ore into processing units during the smelting process. The site also offered features that would aid in efforts to minimize any negative impacts of the facility on nearby residents; the facility was isolated from populations, and a prevailing northwesterly wind carried emissions up-canyon, away from communities. In addition, ISR owners performed an agricultural survey prior to smelter construction, purchased surrounding ranches, and secured options for land within a two mile radius of the site. In the early years of operation, tailings, slag, and flue dust were produced at an annual rate of approximately 650,000 tons/year; those wastes were disposed on-site. As ore supplies began declining, output decreased. The copper smelter was closed in 1946, and lead smelting ceased by 1972 when the complex was razed [Comp 1975; UDEQ 1997].

In 1948, Anaconda Copper acquired the Carr Fork property, located on 12.5 acres west of the ISR property. After extensive exploratory efforts, operations in Carr Fork began in August 1979. Carr Fork experienced several setbacks during its operation, and selected properties were sold to Kennecott Copper Corporation in October 1985. The mill was eventually dismantled and sold off-site in 1986 [Comp 1975; UDEQ 1997].

Site Characterization

The ISR property is approximately 2.5 miles northeast of the city of Tooele, Tooele County, in north-central Utah. The site is near the mouth of Pine Canyon, on the west flank of the Oquirrh mountains (Figure 1). The property lies on late Tertiary and Quaternary sand and gravel of ancient Lake Bonneville deposits. The smelter and distal tailings ponds are on alluvial fan deposits of Pine Creek. Sediment thickness depends on distance from canyon wall and ranges from 1 foot to 1,400 feet. Soil in the area of the site consists mainly of mine dumps, comprised of rock fragments removed during the mining process, and slickens, a fine-textured milling waste material. The canyon bottom is comprised of cobbly loam of the Yeates Hollow series, and the fan terraces consist of Kapod gravelly loam [E&E 1985; JBR 1986; UDEQ 1997].

The annual mean precipitation at the site is less than 10 inches per year, although the head of Pine Canyon is reported to receive 40 inches per year, resulting in heavy spring run-offs. The ISR site is drained mainly to the north by Pine Creek, which flows over the alluvial fan under the smelter and distal tailings pond. To the south, the site is drained by Dry Creek, an ephemeral stream that flows in response to rainfall and snowmelt. Groundwater flow appears to be north or northwest, towards the Great Salt Lake. Because of the complex local geology, depth to groundwater at the site is variable. Beneath the tailings pond, the groundwater depth is greater than 500 feet, whereas 400 yards southeast, it is at ground level [E&E 1985; JBR 1986; UDEQ 1985].

Demographics and Land Use

For the purposes of this document, EEP generated a property boundary for ISR that encompasses all reclaimed areas where contaminant levels were elevated. The property boundary is illustrated in Figure 2. This boundary deviates from the ISR site boundaries established by the U.S. Environmental Protection Agency (EPA) because the latter is undergoing modification as further characterization of the site and associated contaminants progress.

According to 1990 U.S. census data, 223 people live within one mile of the reclaimed ISR property boundaries in the town of Lincoln and the city of Tooele (Figure 2). (Although the town of Lincoln was recently renamed "Pine Canyon," the town will be referred to by the name of "Lincoln" in this document). Of those residents, 93 are children under the age of 18, 113 are between the ages of 18 and 65, and 17 are over the age of 65 [Census 1990]. In the past several years, new residential developments have been built in eastern Lincoln and northeastern Tooele that have increased those 1990 population estimates. A 1999 estimate indicates that 482 people are residing within two miles west of the ISR site. Of those people, 65 were between the ages of 3 and 12, and 53 were between the ages of 12 and 18 [EEP 2000a]. These estimates, however, may not be representative of the entire population of Lincoln, and data from the 2000 U.S. Census are needed for confirmation.

Tooele County has experienced moderate, steady growth since 1942 when Tooele Army Depot and Dugway Proving Ground opened. According to 1995 estimates, the county has a population of about 27,000 residents. Affordable housing prices are drawing people to the area. By 2000, the population was expected to exceed 33,000 people. The Federal Government (Tooele Army Depot, Dugway Proving Ground, and Deseret Chemical Depot) remains the area's largest employer [Babitz, 1996].

Despite efforts to limit access to the ISR site, evidence of trespassing exists. Signs have fallen, have faded, or have been vandalized. Fencing and gated entrances have been vandalized to allow access onto the site. Off-road motorcycle and all terrain vehicle tracks are on and near the site [EEP 2000b; UDEQ 1997]. During the 1995 Utah Department of Environmental Quality (UDEQ) sampling activities and the 2000 EEP site visit, children were observed playing on bare soils in yards in Lincoln [EEP 2000b; UDEQ 1997]. Several homes in the area had vegetable gardens in their yards.

No drinking water or irrigation wells are in use on site. The town of Lincoln obtains drinking water from springs in Murray Canyon, 2 miles north of the ISR site. However, one Lincoln home, approximately 2 miles west-northwest of the site, uses groundwater for irrigation and drinking water. The northernmost houses in Lincoln are approximately one-half mile west and down gradient of Pine Creek. The community of Erda (4 miles north-northwest of ISR) uses water from individual wells for drinking, with several of those wells penetrating the local aquifer. Drinking water for the city of Tooele is obtained from wells and springs in Middle Canyon, 3 miles south of the site. The nearest municipal well, located approximately 3 miles southwest of the site, is operated by the city of Tooele and supplies an unknown number of residents [JBR 1986; UDEQ 1997].

Water from Pine Creek is no longer used for irrigation in Lincoln. However, horses and cattle that occasionally graze in the range northwest of the site have access to Pine Creek water before it goes underground, approximately one mile northwest of the site. Wetlands mapped by the U.S. Fish and Wildlife Service along the 3 mile route through Pine Canyon have approximately 12 acres of frontage on Pine Creek. Although human access to the ISR site is restricted by fencing and signs, wildlife access is unrestricted [JBR 1986; UDEQ 1997].

Remediation Activities

The Utah Mined Land Reclamation Act of May 1975 required reclamation of the Carr Fork operations. The ISR smelter was "pre-law" and was not required to be reclaimed. However, because tailings from Carr Fork were superimposed onto ISR dumps, some of the ISR property was included in the reclamation effort. Eventually, all ISR property was included with the Carr Fork reclamation. The combined reclaimed property, illustrated in Figure 2, lies on approximately 1,200 acres and includes the smelter areas, small waste piles (125 acres), slag piles (28 acres), tailings (326 acres), settling ponds (13 acres), several landfills areas (50 acres), former rail beds, parking lots, and several open areas [E&E 1985; JBR 1986; UDEQ 1997].

Reclamation work conducted in 1986 and 1987 included removal of remaining buildings and structures, consolidation of waste materials, construction of storm water controls, placement of a soil cap, and revegetation over the majority of the site. Building debris and surplus equipment were placed and compacted into the Carr Fork landfill on the eastern portion of the smelter site. Some waste piles were relocated to the newly constructed waste isolation cell and capped with five feet of soil. Approximately 14,240 linear feet of sediment berms were constructed to redirect storm water runoff. A cap of 6-8 inches of topsoil and lime over much of the ISR site was reseeded, excluding the dump area that did not receive any additional soil cover during reclamation. Those reclamation efforts were not entirely successful. The soil cover has not supported vigorous plant growth, and erosion is occurring in several areas [EPA 1999c; UDEQ 1997].


DISCUSSION

Nature and Extent of Contamination

Damage to flora and fauna from sulfur dioxide emissions was documented by Anaconda personnel as early as 1911. UDEQ, formerly the Utah Division of Environmental Health, initiated a site inspection for ISR in 1984. Arsenic, cadmium, lead, and zinc were the main contaminants found in samples collected from tailings, slag, and soils. Surface water samples collected from Pine Creek contained elevated levels of arsenic, cadmium, and lead; slag was noted as present in the bed of Pine Creek. Groundwater samples collected from springs surfacing at the edge of a slag pile were contaminated with levels of lead and cadmium that exceeded background levels. Contaminants were found to have migrated off site; elevated levels of arsenic and lead were found in soil samples from Middle Canyon, the main watershed for the city of Tooele. However, no evidence of contamination of drinking water from Middle Canyon, the watershed for Lincoln, was found [UDEQ 1985].

The EPA field investigation team, Ecology and Environment, inspected the ISR site in 1985. Tailings, which were observed to be blowing from the tailings piles, contained elevated levels of arsenic, copper, lead, and zinc. Subsurface samples collected beneath the tailings contained increased concentrations of those contaminants, indicating some motility of the contaminants into the underlying strata. Up- and down-gradient surface water samples were not notably different, with the exception of mercury content, which had a threefold increase in downstream concentrations. However, because that increase is less than an order of magnitude, mercury was not included in the EPA Hazard Ranking System completed for the site. 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. EPA proposed further investigations of air quality, stream sediments, and groundwater [E&E 1985].

In 1985, JBR Consultants was contracted by Anaconda Copper to initiate an environmental study and reclamation of the area. 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. Some soil samples, taken from depths of four feet, contained elevated levels of lead and arsenic. Smelter waste, concentrator tailings, waste dumps, and landfills were shown to contain many of the metals tested. Levels of lead exceeded EPA maximum contaminant levels (MCLs) in two surface water samples and all five groundwater samples collected. Cadmium exceeded the EPA MCL in one surface water sample. (The MCL is applicable only for public drinking water supplies. If the surface water is used for public drinking water supplies, then treatment is required to lower levels of contaminants that exceed MCLs.) The reclamation plan for ISR included waste site stabilization, sediment and drainage control, addition of top soil, and revegetation [JBR 1986].

The Division of Environmental Response and Remediation of UDEQ performed an Expanded Site Inspection in 1996. UDEQ reported that reclamation was inadequate. Tailings and slag piles contained above background levels of several metals: arsenic, cadmium, cobalt, copper, mercury, selenium, silver, thallium, and zinc. Soil caps overlying numerous source areas were sparsely vegetated and some were eroding. Several tailings piles were actually deposited along the drainage of Dry Creek, and slag piles were in contact with water flowing in Pine Creek. 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. Tables 1-5 list the contaminants found in the source, in on- and off-site soils, in surface water, and in groundwater that exceeded background levels in the Salt Lake County/Wasatch Front area. Figure 3 illustrates the sample collection locations [UDEQ 1997].

Exposure Pathways Analysis

To determine whether nearby residents and on-site visitors are exposed to contaminants related to a site, ATSDR evaluates the environmental and human components that lead to human exposure. An exposure pathway consists of five elements:

(1) a source of contamination;
(2) transport through an environmental medium;
(3) a point of exposure;
(4) a route of human exposure; and
(5) a receptor population.

ATSDR categorizes an exposure pathway as either completed or potential. Completed exposure pathways have all five elements, and exposure to a contaminant has occurred in the past, is occurring, or will occur in the future. In potential exposure pathways, at least one of the five elements has not been identified but could exist. Exposure to a contaminant could have occurred in the past, could be occurring, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present [ATSDR 1992].

Comparison values (CVs) used in this discussion are meant only to screen for contaminants which require further evaluation. Levels of exposure above these values 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. Because of the perimeter fencing and remoteness of the site, we assumed that only adults would gain access to the site by trespassing; thus, for on-site exposures, comparison values for adults were used. Off-site exposures could affect both adults and children in neighboring communities. For those evaluations, we used comparison values for the more susceptible population, children. EEP estimated exposure doses, evaluated pathways of exposure to contaminants, and evaluated the implications of such exposure doses on public health.

Completed Exposure Pathways

On-Site Smelter Waste and On-Site Soil

Completed exposure pathways to contaminated on-site waste, tailings, slag, and soil were found (Table 6). On-site waste, tailings, and slag consist of accumulations of ore, concentrates, flue dust, debris, and landfill wastes generated by smelting mills and can range in size from sand particles to larger solids. In this document, the combined residue is referred to as "smelter waste." Smelter waste samples contained arsenic, cadmium, and lead at levels that exceed soil CVs for adults (Table 1). Maximum concentrations in smelter waste for all three metals were found in sample SC-13, which was collected near the former smelter site (Figure 3). SC-13 contained 5,420 parts per million (ppm) arsenic, 174 ppm cadmium, and 61,300 ppm lead. On-site and up-canyon soil samples collected between 6 to 12 inches below the surface contained arsenic and lead at concentrations greater than soil CVs for adults (Table 2). Maximum concentrations for both metals were found in sample SO-18, located near a former tailings dike in the western portion of the ISR site. SO-18 contained 1,100 ppm arsenic and 4,300 ppm lead. The soil CVs for arsenic, cadmium, and lead are 200 ppm, 100 ppm, and 400 ppm, respectively [ATSDR 1999a; EPA 1998]. Background levels for Wasatch Front are included in Tables 1 and 2.

On-site exposure to contaminated tailings, slag, and soil occurs mainly through oral ingestion and inhalation of contaminated dust. Although perimeter fencing is at the ISR site, EEP staff observed evidence of on-site recreational usage, including off-road vehicle trespassing [EEP 2000b]. We assume that only a small number of persons trespass onto the property and that they are most likely adults and young adults. However, some of those persons might trespass on a regular basis and, thereby, increase their exposure. This pathway has been demonstrated to have existed in the past, and because entrance onto the site is insufficiently restricted, it is also a current and future exposure pathway.

Off-Site Soil

A completed exposure pathway to contaminated off-site soil was found (Table 6). Although no specific monitoring for biological indicators has occurred in any of the potentially exposed populations, evidence has been found that ISR contaminants have affected residences off-site. Samples collected from soils in the Lincoln community and the surrounding vicinity contained lead and/or arsenic at concentrations greater than soil CVs for children (Table 3). Maximum concentrations for metals were found in the second closest residence to the ISR site; SO-7 contained 79.5 ppm arsenic, 12.9 ppm cadmium, and 1,040 ppm lead. UDEQ staff noted that children were playing with toy trucks on bare soil at the residence from which SO-5 was taken [UDEQ 1997]. SO-5 contained 55.3 ppm arsenic, 11 ppm cadmium, and 674 ppm lead. The soil comparison values for children are 20 ppm arsenic, 10 ppm cadmium, and 400 ppm lead [ATSDR 1999a; EPA 1998]. Background levels for Wasatch Front are included in Table 3.

Although reclamation work in 1986 and 1987 attempted to control movement of contaminants by implementing erosion controls, by adding a soil cap, and by revegetation, off-site migration has not been eliminated. The soil cover has not supported vigorous plant growth, erosion is occurring in several areas, and contaminants are migrating off-site.

Off-site exposure to contaminated soil occurs mainly through oral ingestion and inhalation of contaminated soil particles. The exposed populations include communities within 2 miles of the ISR site: the residents of Lincoln and subdivisions in eastern Tooele. With high velocity winds, the town of Erda (4 miles north-northwest) and other regions of Tooele (2 miles south-southwest) could also be affected by off-site migration of contaminated soil. This pathway has been demonstrated to have existed in the past, and because additional erosion control measures have not been implemented, it is also a current and future exposure pathway.

Potential Exposure Pathways

On- and Off-Site Surface Water

A potential pathway of exposure to contaminants in on- and off-site surface water was found (Table 7). Although up canyon, on-site, and background samples all contained levels of arsenic that exceeded drinking water CVs for children, samples collected downgradient and off-site exceeded those CVs by a factor of 10 (Table 4). For on-site samples, maximum concentrations for metals were found in sample SW-05, which was taken from a point where the slag pile is in contact with Pine Creek. Sample SW-05 contained arsenic at 5.9 parts per billion (ppb). For off-site samples, maximum concentrations for metals were found in SW-07, which contained arsenic (32 ppb), lead (151 ppb), and cadmium (3.2 ppb). However, the data for SW-07 is questionable because the sampling location depicted in Figure 3 is not on the Pine Creek drainage. The drinking water CV for children is 3 ppb for arsenic, 2 ppb for cadmium, and the EPA action level for lead is 15 ppb [ATSDR 1999b; EPA 2000].

Co-located sediment samples collected with the surface water samples revealed that release of contaminants from surface water to underlying soil occurred (Table 4). In general, the higher the level of contaminant in a sample of surface water, the higher the level of contaminant found in the co-located sediment. Because regional hydrogeology indicates that overland flow is mainly towards the Great Salt Lake, the communities which lie down gradient from the ISR site are potentially exposed to contaminants migrating in surface water.

On- and off-site exposure to contaminated surface water can occur through incidental contact or accidental oral ingestion. Because Pine Creek water is not a drinking water source and because visitation to the site is occasional, the potential for significant contaminant exposure through this pathway is considered low. Nevertheless, this pathway may have existed in the past, and because no action has been taken to eliminate the source of the contamination, it may also be a current and future exposure pathway.

Groundwater pathway

A potential pathway of exposure to contaminated groundwater was found (Table 7). Arsenic levels in groundwater near the ISR site exceed the CVs for drinking water for children (Table 5). The maximum arsenic concentration found in all samples was found in a downgradient well, GW-04, with a value of 149 ppb. The drinking water CV for children is 3 ppb for arsenic [ATSDR 1999b].

Limited groundwater sampling data exist for ISR. The 1985 JBR study indicated that the water chemistry of the water wells on and near the site complied with primary drinking water standards but exceeded the secondary standards for sulfates and total dissolved solids. Because of the depth to groundwater (approximately 500 feet), the ability of the dry, unsaturated sediments overlying the aquifer to absorb and retain infiltrating water, and the contamination attenuation capacity of these sediments, JBR concluded that groundwater contamination is unlikely [JBR 1986]. According to the 1997 UDEQ report, wells in the town of Erda, which are recharged by groundwater from Pine Canyon, contained nitrate levels that exceed EPA MCLs [UDEQ 1997]. UDEQ did not find elevated nitrate levels in other off-site wells in 1985 and 1995, possibly because these wells were completed in aquifers different from those wells in Erda. Additional groundwater sampling must be done to determine any association between nitrate contamination in Erda and the ISR site.

Although these are limited and preliminary data, sufficient evidence was found to suggest that contaminated groundwater is a potential pathway of exposure. Most Lincoln residents obtain their drinking water from other sources; however, one Lincoln home, approximately two miles west-northwest of the site, uses groundwater for irrigation and drinking water. This pathway may have existed in the past, and because no action has been taken to eliminate the source of the contamination, it may also be a current and future exposure pathway.

Public Health Implications

To determine if the contaminants pose a public health threat, the exposure doses to chemicals of concern were estimated (Appendix B). For on-site smelter waste and on- and off-site soil, the estimated doses for chemicals of concern for adults did not exceed the ATSDR Minimal Risk Levels (MRLs), and adverse health effects are unlikely to occur as a result of exposure (Tables 8-10). However, for children exposed to arsenic, cadmium, and lead through the off-site soil pathway, the estimated doses exceed the ATSDR MRLs (Table 10), and adverse health could result under some exposure conditions. For that reason, we evaluated the toxicological effects of arsenic, cadmium, and lead, with particular emphasis on children.

Toxicological Evaluation

Arsenic, cadmium, and lead are the chemicals of concern for the ISR site. Those metals are present in soil at concentrations that could be of potential health concern for children residing in the area. As previously discussed, ingestion of contaminated soils is the most likely exposure pathway, although inhalation of contaminated particles can also contribute to the total exposure. Because no air sampling data are available, only the ingestion pathway is evaluated further.

Arsenic

Arsenic is a naturally occurring element and is found in two forms; inorganic arsenic is formed when arsenic is combined with oxygen, iron, and sulfur, and organic arsenic is formed when arsenic is combined with carbon and hydrogen. The inorganic forms of arsenic, commonly found at smelter sites because they are derived from treating copper and lead ores, are usually more harmful than the organic forms. Both forms have no smell, and most forms have no special taste [ATSDR 1993a, 1999c].

Most of the arsenic ingested from contaminated water, soil, or food quickly enters into the body. Inhalation of arsenic-contaminated dusts can result in contaminated dust particles settling onto the lining of the lungs and subsequent entry of arsenic into the body. Exposure through the skin is not sufficient enough to be a concern. The body usually eliminates arsenic through the urine [ATSDR 1993a, 1999c].

For arsenic, the no observable adverse effect level (NOAEL) is 0.0008 milligrams per kilogram of body weight per day (mg/kg/day), and the lowest observable adverse effect level (LOAEL) is 0.014 mg/kg/day [ATSDR 1999c]. For an explanation of those terms, see Appendix A. As shown in Table 10, the estimated dose for children in Lincoln is 0.0013 mg/kg/day. Because the estimated dose does not exceed the LOAEL range, it is not considered sufficient to lead to a significant increase in frequency or severity of adverse effects upon exposure. Of note, however, is that in one study in children, a dose of 0.0008 mg/kg/day arsenic produced adverse dermal effects (hyperkeratosis and hyperpigmentation) after 3 to 7 years of exposure to arsenic, tin, and tungsten [Foy et al. 1992]. However, in a study of 17,000 people, the same exposure of 0.0008 mg/kg/day produced no health effects [Tseng et al. 1968]. In conclusion, an estimated dose of 0.0013 mg/kg/day of arsenic through ingestion of contaminated soil is not expected to cause adverse health effects. No air sampling data are available to determine the exposure to inhaled arsenic particles.

Large oral doses of inorganic arsenic (above 60,000 ppb in food or water) can produce death. The ingestion of lower levels of inorganic arsenic (ranging from about 300 to 30,000 ppb in food or water) might cause irritation of the stomach and intestines, with symptoms such as pain, nausea, vomiting, and diarrhea. Other effects from swallowing arsenic may include decreased production of red and white blood cells, abnormal heart rhythm, blood-vessel damage, and impaired nerve function causing a "pins and needles" sensation in your hands and feet. No reliable evidence in humans has been found that indicates arsenic can injure pregnant women or their fetuses. Animal studies show that arsenic in doses of up to 1 mg/kg/day in drinking water have no significant health effects on reproduction. No studies have been conducted to assess reproductive effects after inhalation exposure to arsenic [ATSDR 1993a, 1999c].

Perhaps the most characteristic effect of long-term oral exposure to inorganic arsenic is a pattern of skin changes. This includes a darkening of the skin and the appearance of small "corns" or "warts" on the palms, soles, and torso. While those skin changes are not considered to be a health concern in their own right, a small number of the corns may ultimately develop into skin cancer. Dermal effects are common in people exposed to arsenic by the oral route but are rare in people exposed by inhalation. Numerous studies in humans have reported dermal effects at chronic dose levels ranging from 0.01 to 0.1 mg/kg/day [ATSDR 1993a, 1999c].

The ingestion of arsenic has been reported to increase the risk of cancer in the liver, bladder, kidney, and lungs. Arsenic is considered a human carcinogen by the National Toxicology Program (NTP), the International Association of Research on Cancer (IARC), and EPA [ATSDR 1993a, 1999c].

Cadmium

Cadmium is an element that occurs naturally in the earth's crust. It is usually found as a mineral combined with other elements such as oxygen, chlorine, or sulfur. All soils and rocks, including coal and mineral fertilizers, have some cadmium in them. Most cadmium used in this country is extracted during the production of other metals such as zinc, lead, or copper. Cadmium cannot be detected in air or water by smell or taste because it does not have any definite taste or odor [ATSDR 1993b, 1999d].

Cadmium can enter the body by ingesting contaminated food or water, or from inhaling contaminated dust particles. Very little cadmium enters through the skin. The body rapidly absorbs about one-quarter of the cadmium inhaled and about one-twentieth of the cadmium ingested. Cadmium that enters the body stays in the liver and kidneys. Cadmium leaves the body slowly in the urine and feces [ATSDR 1993b, 1999d].

Chronic exposure studies in humans indicate that the NOAEL is 0.0021 mg/kg/day and the LOAEL is 0.0078 mg/kg/day [ATSDR 1999d]. As shown in Table 10, the estimated dose for children in Lincoln is 0.00021 mg/kg/day. Because the estimated dose for children is less than the NOAEL and LOAEL, adverse health effects are not expected as a result of cadmium exposure through the ingestion route. No air sampling data are available to determine the exposure resulting from inhaled cadmium particles.

Cadmium has no known beneficial health effects. Breathing air with very high levels of cadmium, 6.8 milligrams per cubic meter (mg/m3), severely damages the lungs and can cause death. Breathing lower levels (0.023 - 0.067 mg/m3) for years leads to a build-up of cadmium in the kidneys that can cause kidney disease. Other effects that might occur after breathing cadmium for a long time are lung damage and fragile bones. Animal studies suggest that inhaling cadmium particles can reduce fertility, increase the rate of birth defects, and damage the liver and immune system. Scientists do not know whether cadmium has the same effects in humans. Eating food or drinking water with very high cadmium levels (13-16 milligrams per liter [mg/L]) severely irritates the stomach, leading to vomiting and diarrhea. Eating lower levels of cadmium over a long period of time leads to a build-up of cadmium in the kidneys, which leads to kidney disease [ATSDR 1993b, 1999d].

Cancer studies of humans and animals that eat, drink, or inhale cadmium are inconclusive. Some studies show that inhaling cadmium causes lung cancer, and other studies show that eating or drinking cadmium does not cause cancer. For those reasons, NTP, IARC, and EPA have determined that cadmium is a probable human carcinogen [ATSDR 1993b, 1999d].

Lead

Lead occurs naturally in the environment; however, most of the lead dispersed throughout the environment comes from human usage. Lead is used in paints, ceramic products, caulking, gasoline additives, ammunition, and many other applications. Its use has been reduced in recent years because of lead's harmful effects in humans and animals. People living near hazardous waste sites can be exposed to lead and chemicals that contain lead by breathing air, drinking water, eating foods, or swallowing or touching dust or dirt that contains lead. Once in the body, lead is mainly stored in the bones and teeth until it is excreted in the feces [ATSDR 1993c, 1999e].

Lead can affect almost every organ and system in the body. Unlike the two contaminants previously discussed, the NOAEL, LOAEL, and MRL for lead have not been established. Studies of lead exposure in humans generally do not correlate exposure levels (mg/kg/day) to health effects, but rather studies correlate absorbed dose (concentration of lead in blood) to effects. At very high levels, greater than 40 micrograms per deciliter of blood (µg/dL), lead exposure in adults may decrease reaction time, cause weakness in fingers, wrists, or ankles, possibly affect the memory, and may cause anemia. Lead exposure may also damage the kidneys and the reproductive system. Health effects due to exposure to lower levels of lead is uncertain. Children are particularly sensitive to the toxic effects of lead; that issue is discussed further in the "Lead and Children's Health" section [ATSDR 1993c, 1999e].

Lead is classified as a probable human carcinogen based on studies in rats and mice; however, the high doses used in those studies make it difficult to extrapolate the results to low level exposures to humans [ATSDR 1993c, 1999e].


CHILD HEALTH INITIATIVE

ATSDR recognizes that unique vulnerabilities of infants and children require special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at greater health risk than adults as a result of exposure to some environmental hazards. Children are more likely to be exposed to contaminants because they play outdoors, often bring food into contaminated areas, and are more likely to come into contact with dust and soil. Also, because their bodies are still developing, children can sustain permanent damage if toxic exposures to some contaminants occur during critical growth stages.

Arsenic and Children's Health

Children who are exposed to arsenic exhibit the same affects as adults. The development of cancer has been observed in adults who were exposed to arsenic as children or young adults. Studies in animals show that arsenic crosses the placenta and is found in fetal tissues. Animals exposed to arsenic show developmental damage, including neural tube defects and disruption of kidney development [ATSDR 1993a, 1999c]. In the town of Lincoln, the estimated dose for children is 0.0013 mg/kg/day, a level which is not expected to cause adverse health effects.

Cadmium and Children's Health

The health effects in children from exposure to toxic levels of cadmium are expected to be similar to the effects seen in adults: kidney, lung, and intestinal damage, depending on the route of exposure. The effects are most easily seen in short-term, high-level exposures. Harmful effects on child development or behavior have not generally been seen in populations exposed to cadmium, but more research is needed. Cadmium has not been shown to cause birth defects in people. Cadmium does not readily transfer from a pregnant woman's body into the developing child, but some portion can cross the placenta. It can also be found in breast milk. The babies of animals exposed to high levels of cadmium during pregnancy showed changes in behavior and learning ability. Cadmium may also affect birth weight and the skeleton in developing animals. A balanced diet that includes enough calcium, iron, protein, and zinc will help reduce the amount of cadmium that may be absorbed in the body [ATSDR 1993b, 1999d]. In the town of Lincoln, the estimated dose for children is 0.00021 mg/kg/day, a level which is not expected to cause adverse health effects.

Lead and Children's Health

Many children are repeatedly exposed to lead during their childhood. A mother with lead in her body can expose the fetus to lead through the placenta. After birth, the mother could continue to expose her baby to lead through breast feeding. Children can be exposed to lead if they eat food or drink water that contains lead. Children can swallow and breathe lead in dirt, dust, or sand while they play on the floor or the ground. The dirt or dust on a child's hands, toys, and other objects with which the child comes into contact may have lead particles on them. In some cases, children swallow non-food items such as paint chips, particularly in older homes with lead-based paint, which may contain large amounts of lead. Also, compared to adults, a larger proportion of the amount of lead swallowed will enter the blood in children [ATSDR 1993c, 1999e].

Children are more sensitive to the effects of lead than adults. Fetuses exposed to lead in the womb (because of the mother's high blood lead levels) may be born prematurely and have lower weights at birth. Exposure in the womb, in infancy, or in early childhood may also slow mental development and result in lower intelligence later in childhood. Evidence has been found that some effects may persist beyond childhood [ATSDR 1993c, 1999e]. Because the levels of exposure to lead found in the environment that might result in adverse health effects have not been determined, ATSDR and EEP recommend that any exposure to lead be avoided whenever possible.

The Centers for Disease Control and Prevention (CDC) determined that blood lead levels greater than 10 µg/dL in children are considered elevated, and some studies suggest that intelligence might be affected when levels are as low as 7 µg/dL [CDC 1991, 1997]. Blood lead levels as low as 10 µg/dL can adversely affect the behavior and development of children [ATSDR 1993c]. Learning disabilities have been observed in children with blood levels exceeding 40 µg/dL [ATSDR 1993c, 1999e].


COMMUNITY HEALTH CONCERNS

On August 3, 2000, TCHD and EEP held a public availability session at the Tooele County Health Department in Tooele. The hours were 11:00 a.m. to 2:00 p.m. and again at 5:00 p.m. to 8:00 p.m. The public was invited, as were representatives from UDEQ and EPA The purposes of the session were to (1) release the initial draft of this public health assessment for public comment and to (2) better understand community health concerns. Posters and printed material explained the health hazards associated with the site. The session was well attended by government officials with representatives from TCHD, UDOH, UDEQ, USGS, and EPA who were available to answer questions. Ten residents of Lincoln were able to attend, some people brought their children.

Community health concerns and comments to the initial release of this public health assessment are listed in Appendix C.


CONCLUSIONS

The ISR site is a public health hazard (ATSDR health hazard category B). Although no biomonitoring data have been collected to provide information on actual exposure levels, the environmental levels of lead pose a likelihood that exposure has occurred and continues to occur for residents who live near the site and for visitors at the site. Arsenic, cadmium, and lead are the contaminants of concern, although lead is the one contaminant present at levels that could result in adverse health effects, especially in children. Of particular concern is the potential for long-term developmental health effects on children residing near the site as a result of lead exposure. The main route of exposure is through ingestion of smelter waste and contaminated soil both on- and off-site.

Although limited, data indicate that surface water and groundwater are contaminated. Off-site migration of contaminants in soil, surface water, and groundwater may potentially extend to downgradient communities, thereby increasing the population potentially exposed.


RECOMMENDATIONS

Exposure Reduction Recommendations

Inform Lincoln residents supplied by individual wells of the potential for groundwater contamination and recommend testing water for heavy metals.
Establish erosion control measures to prevent contaminant migration off-site.
Replace fallen, faded, or unreadable signs.
Improve access restrictions with effective measures such as replacing barbed wire fencing with more secure chain link fencing equipped with locked gates to keep trespassers off the site until final remediation is complete.
Prevent further contamination of Dry Creek and Pine Creek with effective measures such as removing tailings and slag piles from the drainage area of both creeks and covering tailings and slag piles with soil cap.

Site Characterization Recommendations

  1. Conduct additional sampling of on- and off-site groundwater, surface water, and sediment to characterize adequately the extent of on-and off-site contamination.

  2. Conduct additional sampling of residential yards in Lincoln and the Carr Fork subdivision in eastern Tooele to characterize the extent of contamination in those communities and remediate those properties that exceed EPA action levels.

Health Activities Recommendations

  1. Provide community health education to the exposed populations about the possible health effects from exposure to site contaminants and about interim measures that can be taken to reduce exposures.

  2. Provide free annual blood lead testing for children ages 6 months to 6 years of age living in the community of Lincoln.

PUBLIC HEALTH ACTION PLAN

This section describes the public health action plan for EEP staff members and other government agencies at and near the ISR site. This public health action plan, designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment from the ISR site, consists of the following past and future actions:

EEP, in coordination with other local and state agencies, conducted a public availability session for residents of Lincoln and the Carr Fork subdivision in Tooele. At the session, EEP addressed health concerns related to the ISR site, provided information on the contaminants, and outlined measures people could take to reduce exposure.

The Tooele County Health Department (TCHD) offered free blood lead testing for children ages 6 months to 6 years of age living in the communities of Lincoln and the Carr Fork subdivision in Tooele during the year 2000.

EEP will provide environmental health education materials to residents of Lincoln and the Carr Fork subdivision in Tooele through the Tooele County Health Department (TCHD). The materials will provide information on lead poisoning prevention and will outline dust control methods.

EEP continues to monitor the Utah Blood Lead Registry for children with elevated blood lead levels in areas near the site.

EEP will provided the Utah Department of Environmental Quality (UDEQ), the United States Environmental Protection Agency (EPA), and the site owner with copies of this public health assessment so that they are aware of our recommendations. All of their comments and questions have been addressed, and actions are coordinated.

TCHD and EEP will continue to work with agencies such as UDEQ and the EPA to address the public health issues related to the ISR site.


AUTHORS

M. Gambrelli Layco, M.F.S., Toxicologist
Bureau of Environmental Chemistry & Toxicology
Utah Department of Health
(801) 584-8463

R. Wayne Ball, Ph.D., D.A.B.T.
Program Manager / Toxicologist
Environmental Epidemiology Program
Bureau of Epidemiology
Utah Department of Health
(801) 538-6191


CERTIFICATION

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

Gail D. Godfrey
Technical Project Officer
Division of Health Assessment and Consultation
ATSDR


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

Richard E. Gillig
Chief, Superfund Site Assessment Branch
Division of Health Assessment and Consultation
ATSDR


REFERENCES

ARCO, 2000. Atlantic Richfield Company Environmental Remediation, L.L.C.'s draft of International Smelting and Refining/Carr Fork RI/FS Work Plan

ATSDR, 1992. The Agency for Toxic Substances and Disease Registry Public Health Assessment Guidance Manual. Chelsea, Michigan: Lewis Publishers, 1992.

ATSDR, 1993a. ATSDR's Toxicological Profiles on CD-ROM, Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services, CRC netBASE, 1999. Toxicological Profile for Arsenic. Prepared by Life Systems, Inc., April 1993.

ATSDR, 1993b. ATSDR's Toxicological Profiles on CD-ROM, Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services, CRC netBASE, 1999. Toxicological Profile for Cadmium. Prepared by Life Systems, Inc., April 1993.

ATSDR, 1993c. ATSDR's Toxicological Profiles on CD-ROM, Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services, CRC netBASE, 1999. Toxicological Profile for Lead. Prepared by Clement International Corporation, April 1993.

ATSDR 1999a. Soil Comparison Values (Update). U.S. Department of Health and Human Services, Public Health Service. Atlanta, Georgia.

ATSDR, 1999b. Drinking Water Comparison Values (Update). U.S. Department of Health and Human Services, Public Health Service. Atlanta, Georgia.

ATSDR, 1999c. The Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services. Prepared by Research Triangle Institute. Toxicological Profile for Arsenic. Atlanta: July 1999.

ATSDR, 1999d. The Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services. Prepared by Research Triangle Institute. Toxicological Profile for Cadmium. Atlanta: July 1999.

ATSDR, 1999e. The Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services. Prepared by Research Triangle Institute. Toxicological Profile for Lead. Atlanta: July 1999.

Babitz, Marc E.,1996, Health Needs Assessment of Tooele County.

Census, 1990, Bureau of Census, Census of Population and Housing, Summary Population and Housing Characteristics, Utah.

CDC, 1991. Centers for Disease Control and Prevention. Preventing lead poisoning in young children. Atlanta, GA: United States Department of Health and Human Services, Public Health Service.

CDC, 1997. Centers for Disease Control and Prevention. Screening Young Children for Lead Poisoning: Guidance for State and Local Public Health Officials.

Comp, T. Allen, 1975, The Tooele Copper and Lead Smelter in Industrial Archaeology, vol I, no. I, pp. 29-46.

E&E, 1985. Ecology and Environment, September 27, 1985, Field Investigation Team Analytical Results for Tooele Smelter, TDD R8-8508-09.

EEP, 2000a. Environmental Epidemiology Program. Memorandum for the Record, Personal Communication with Ward and Stakes Information Division of the LDS Headquarters Office, February, 7, 2000.

EEP, 2000b. Environmental Epidemiology Program. Memorandum for the Record, February 16, 2000. International Smelting and Refining, Tooele County, Utah, Bureau of Epidemiology, Utah Department of Health, Salt Lake City, Utah.

EPA, 1998. The U.S. Environmental Protection Agency. Solid Waste and Emergency response. Clarification to the 1994 Revised Interim Soil Guidance for CERCLA Sites and RCRA Corrective Action Facilities. EPA 540-F-98-030, NTIS: PB98-9630244.

EPA, 1999a. The U.S. Environmental Protection Agency. CERCLIS Query Results for International Smelting and Refining, CERCLIS # UTD093120921. http://www.epa.gov:9966/envirodcd/cerclis_web.report?pgm_sys_id=0800650 accessed August, 1999.

EPA, 1999b. Integrated Risk Information Systems (IRIS). Online. The National Library of Medicine: Specialized Information Services - TOXNET (Toxicology Data Network). http://sis.nlm.nih.gov/cgi-bin/sis/htmlgen?IRIS accessed November, 1999.

EPA, 1999c. EPA Hazard Ranking Documentation Record for International Smelting and Refining, CERCLIS # UTD093120921. Prepared February, 1999.

EPA, 2000. Office of Water. Office of Ground Water and Drinking Water. Online. Current Drinking Water Standards. National Primary and Secondary Drinking Water Regulations. http://www.epa.gov/OGWDW/wot/appa.html, Accessed February, 2000.

Foy HM, Tarmapai S, Eamchan P, et al. 1992 cited in The Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services. Prepared by Research Triangle Institute. Toxicological Profile for Arsenic. Atlanta: July 1999.

NAS, 1980. National Academy of Sciences, 1980 cited in The Agency for Toxic Substances and Disease Registry. ATSDR's Toxicological Profiles on CD-ROM, Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services, CRC netBASE 1999. Toxicological Profile for Copper. Prepared by Syracuse Research Corporation, December 1990.

Tseng WP, Chu HM, How SW, et al. 1968 cited in The Agency for Toxic Substances and Disease Registry, the U.S. Department of Health and Human Services. Prepared by Research Triangle Institute. Toxicological Profile for Arsenic. Atlanta: July 1999.

UDEQ, 1985. Utah Department of Environmental Quality (Formerly Utah State Division of Environmental Health), August 31, 1985, Site Inspection of Tooele Smelter and Anaconda - Carr Fork Operation, Tooele, Utah UTD093120921.

UDEQ, 1997. Utah Department of Environmental Quality (UDEQ), Division of Environmental Response and Remediation (DERR), June 2, 1997, Analytical Results Report, Anaconda Copper - Carr Fork Site, Vol 1 of 3.


1. The Tooele Valley Railroad runs from the ISR site, through fields with grazing animals, past a school, and through residential areas of Tooele. The spur appears to be made of slag and other waste materials from the site. Preliminary sampling indicates the presence of unsafe levels of lead. The Tooele County Health Department has asked the Utah Department of Health's Environmental Epidemiology Program (EEP) and the Agency for Toxic Substances and Disease Registry (ATSDR) to write a Public Health Assessment for this railroad spur. A Public Health Assessment for the Tooele Valley Railroad Spur is currently underway.


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