PRELIMINARY PUBLIC HEALTH ASSESSMENT
PETROCHEM RECYCLING CORPORATION/EKOTEK
SALT LAKE CITY, SALT LAKE COUNTY, UTAH
In conducting an ATSDR public health assessment, the health assessors identify and review all available environmental contamination data from a site. On- and off-site discussions of this section describe sampling that has been done and identify contaminants of concern. The quality of the environmental data is discussed in the Quality Assurance and Quality Control subsection. Physical and other hazards not related to toxic substances, if any, are described in the Physical and Other Hazards subsection. This introductory section discusses the process for selecting contaminants of concern and Toxic Chemical Release Inventory (TRI) data.
Selection of Contaminants of Concern
ATSDR selects contaminants for further evaluation based upon the following factors:
- comparison of concentrations of contaminants on and off site with values for noncarcinogenic and carcinogenic endpoints,
- sampling plan and field and laboratory data quality, and
- community health concerns.
Identification of a contaminant of concern in the On-Site and Off-Site Contamination subsections does not mean that exposure will result in adverse health effects, only that additional evaluation is necessary. The public health significance, if any, of exposure to the contaminants of concern is evaluated in subsequent sections of the public health assessment.
Comparison values for the public health assessment are contaminant concentrations in specific media that are used to select contaminants for further evaluation. Those values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. CREGs are estimated contaminant concentrations based on a one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors. EPA's maximum Contaminant Level Goal (MCLG) is a drinking water health goal. EPA believes that the MCLG represents a level at which no known or anticipated adverse health effect should occur. Proposed Maximum Contaminant Level Goals (PMCLGs) are MCLGs that are being proposed. Maximum Contaminant Levels (MCLs) represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of two liters of water per day. While MCLs are regulatory concentrations, PMCLGs and MCLGs are not. EPA's Reference Dose (RfD) and Reference Concentrations (RfC) are estimates of daily exposures that are unlikely to cause adverse health effects.
The environmental data reviewed in this document came from two EPA documents that report the preliminary investigation (PI) of the site (7,11). Sampling done for PIs is neither comprehensive nor systematic. Thus, the data from a PI is not as useful for the purposes of a public health assessment as the data from a remedial investigation, which is very comprehensive and systematic. The RI for Petrochem is scheduled to be completed in 1994.
Review of Toxic Chemical Release Inventory (TRI) Data
The EPA Toxic Chemical Release Inventory (TRI) was searched for information on toxic substances used by industries in the area around the site. No releases were reported under the facility names, Petrochem Recycling Company or EkoTek, Inc. for the years 1987-1989 (12). A search by zip code for the same years showed many releases into the air. However, none of the chemicals released were indicated as a health concern in any media at Petrochem/EkoTek. Contaminants of concern related to the site are discussed below.
This section covers contaminants from the Petrochem/EkoTek site that meet ATSDR's guidelines for a contaminant of concern. While some of the contamination is attributable to the site, there are some contaminants, such as heavy metals, that may also have off-site sources. No distinction between sources has been made.
It should be noted that many of the values are estimates. A more accurate assessment of these concentrations is needed to verify levels exceeding ATSDR comparison values. Data quality is discussed in the Quality Assurance and Quality Control section.
The EPA sampled the contents of tanks, drums, and waste piles at the site in 1988 and 1989. They found chlorinated solvents, non-halogenated solvents, phthalate compounds, and polynuclear aromatic hydrocarbons. In addition, low levels of pesticides and high levels of lead were detected. Incinerator ash in soil contained extremely low concentrations of dioxins and furans. Large concentrations of oily waste were cleaned up during removal activities at the site. Since the waste material has been removed from the site and the entry to the plant was restricted when it was in operation, public exposure to the waste material is considered unlikely. Therefore, those data were not summarized in this assessment.
Soil gas and water headspace analyses were conducted in April and May of 1990 (13). The main compounds detected were the chlorinated solvents trichloroethylene and tetrachloroethylene as well as hydrocarbon-derived compounds. The petroleum compounds (benzene, toluene, and xylene) were found primarily in the main tank area with a number of other locations scattered on and off site.
Soil-gas data are not appropriate for determining health impact because they do not measure possible exposure levels. Health impact could be determined by sampling the ambient air near locations where soil gas is identified.
Thirteen soil samples were analyzed for contaminants in 1988 and 1989 (7). The soil samples were taken from the upper few inches of soil, primarily in the waste piles and waste containment areas. ATSDR did not find an exact description of sampling depth in the data it reviewed. EPA found the soil samples contaminated with over 40 organic compounds and metals. The contaminants selected for further evaluation (Table 1, Appendix A) were arsenic, barium, beryllium, cadmium, chromium, lead, manganese, mercury, vanadium, bis(2-ethylhexyl)phthalate, di-n-phthalate, pentachlorophenol, PCBs, and chlordane. However, arsenic, beryllium, manganese, and vanadium are within background concentration ranges for the Salt Lake City area. Most of the metals were found throughout the site, while the organic compounds were identified only at a few locations.
Five wells were examined for on-site contaminants in 1990 (7). Arsenic levels in well PC-MW-8 and lead in well PC-MW-7 met ATSDR's guidelines for contaminants of concern. The remaining contaminants were detected at well PC-MW-7, which is technically outside the property boundaries. However, based on the proximity to the property boundary and the hydrogeologic conditions, it was evaluated as an on-site well. Based on sampling results, on-site groundwater contamination is primarily limited to PC-MW-7. The extent of off-site groundwater contamination has not been determined. Other organic solvents (1,1-dichloroethane, 1,2-dichloroethene and 4-methylphenol), whose concentrations did not meet ATSDR's guidelines for contaminants of concern, were detected in this well. Thus the potential exists for chlorinated solvents and polynuclear aromatic hydrocarbons to migrate from the shallow aquifer to the deeper potable aquifer.
Monitoring of on- and off-site air is described in the Off-Site Contamination section that follows.
Petroleum compounds were found in soil gas west of the main tank farm and in other scattered locations off site. The soil gas to the west probably originated from petroleum products in the groundwater that were found in excavations to the west. Chlorinated solvents were also detected off-site in soil gas. This indicates that off-site groundwater needs to be characterized further to determine the extent of contamination.
In 1989, nine soil samples were taken from off-site locations. One was a background sample and eight were samples taken in residential yards south of the site. The only description of sampling depth was "the upper few inches of soil" (7). Those contaminants selected for further evaluation (Table 3, Appendix A) were arsenic, barium, beryllium, cadmium, chromium, lead, manganese, vanadium, PCBs, chlordane, dieldrin, and heptachlor epoxide. Dieldrin and heptachlor epoxide exceeded comparison values in off-site soils, but not in on-site soils. Beryllium, mercury, bis(2-ethylhexyl)phthalate, di-n-butyl phthalate, and pentachlorophenol did not exceed comparison values in off-site soils, but did in on-site soils. Arsenic, manganese, and vanadium are within background concentration ranges for the Salt Lake City area.
In October of 1987, an employee of the state of Utah, Department of Health observed a significant plume in the air coming from the Petrochem/EkoTek plant. The plume was accompanied by a strong noxious odor (14). Residents reported past strong noxious odors to ATSDR during home visits. Black smoke was periodically observed coming from on-site burners and furnace stacks (5). Before September of 1982, acid-sludge fumes from the acid-sludge truck loading operation were vented to the atmosphere (6). A 1982 plant inspection report indicated several sources of air emissions: volatile organic releases when flares were broken down, release of strong odors (hydrogen sulfide) when lime was mixed with sludge, and particulate emissions when clay and oil were mixed (15). A sulfur scrubber was installed after 1980 to control sulfur emissions. No analytical data of air emissions during plant operations were found for review.
For several days in November of 1990, EPA sampled volatile and semi-volatile organics in air at five monitoring locations. Releases of acetone and 2-methylnaphthalene were observed. The acetone levels do not meet ATSDR's guidelines for a contaminant of concern. There are currently no criteria on which to base a comparison value for 2-methylnapthalene. Estimates of benzene in on- and off-site air exceeded the comparison value (Table 4, Appendix A). Air was not sampled for metals.
Three off-site monitoring wells served as background for water quality at the site. Contaminant levels in these wells did not meet ATSDR's guidelines for contaminants of concerns as shown in Table 5, Appendix A. The background wells, however, are east of the site, and regional groundwater flow is to the northwest. Excavations west of the site showed free phase petroleum product on the groundwater table. Therefore, the potential for groundwater contamination from the site has not yet been fully characterized.
Data presented in Tables 1 through 5 have many qualifiers.
It should be noted that many of the values are estimates. A more accurate assessment of these concentrations is needed to verify levels exceeding ATSDR comparison values. For many values, quality control criteria were not met.
In the past, ponds containing hazardous wastes overflowed, leaking off site. Some of the waste stored on site was flammable and corrosive. Most physical hazards such as waste ponds and piles have been removed from the site.
In this section of the public health assessment, possible exposure pathways are evaluated to help determine whether persons have, are, or will be exposed to contaminants associated with the site. Pathway analysis consists of five elements:
- identifying contaminants of concern,
- determining that contaminants have/are/will be transported through an environmental medium,
- identifying a point of exposure (i.e., a place or situation where humans might be exposed to the contaminated media),
- determining that there is a plausible route of human exposure (i.e., can the contaminant enter the body?), and
- identifying an exposed population (i.e., how many people, if any, are at the point of exposure).
An exposure pathway is considered complete when there is evidence that all five elements exist. The presence of a completed pathway indicates that human exposure to contaminants has occurred in the past, is occurring, or will occur in the future. When one or more of the five elements of an exposure pathway are missing, that pathway is considered potential. The presence of a potential exposure pathway indicates that human exposure to contaminants 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. The completed and potential exposure pathways and estimates of the number of exposed individuals for the Petrochem site are presented in Tables 6 - 8, Appendix B.
Several heavy metals and organic compounds were found in both on- and off-site soil. Since the soil in the residential community to the south is contaminated with some of the same chemicals that are found on site, a completed exposure pathway for ingestion is indicated. Even though the site is fenced, it was accessible through November of 1988 (before fencing). Children have been seen trespassing on site. Surface soil could be ingested while children are playing in residential yards, playgrounds, or while trespassing. The population at risk of ingesting contaminated soils is not as large as the population at risk of exposure to contaminants in air or groundwater. The small number of soil samples taken (9) for the residential area suggests that additional samples are needed for evaluation. To adequately evaluate this pathway, soil in the businesses west of the site and in residential yards south of the site needs to be sampled further.
Ambient Air Pathway
Releases of organics from the Petrochem/EkoTek site have been observed in addition to releases from other sources in the area. The source of benzene documented in air on and surrounding the site has not been defined. There are other potential sources of benzene in the area, such as the operating refinery south of the site. Since releases have occurred, residents in nearby communities and perhaps on-site workers are considered to have been exposed to contaminants via the air pathway.
Petrochem is considered a likely source of past exposures to air contaminants due to air violations recorded at the Utah Bureau of Air Quality, reports by residents, and several sources of on-site air emissions. The Petrochem site could have been the source of this exposure during past operations or during remedial activities. Benzene was identified as a contaminant of concern in that pathway, based on monitoring done after removing the processing units.
The ambient air pathway has not been adequately characterized due to the limited number of samples and the absence of inorganic analyses. In particular, metals data have not yet been gathered; there are several sources of metals in the area. Air monitoring, including collection and evaluation of meteorologic data, needs to be conducted on several different days before the results can be used to evaluate health impact of air-borne volatile organic compounds and particulates. Therefore, without additional sampling, the air pathway cannot be further evaluated.
Potential exposure pathways are indicated if exposure to a contaminant could have occurred, could be occurring, or could occur in the future.
Soil Gas Pathway
Soil gas represents a potential exposure pathway because four of the five elements that form a completed pathway exist. The missing element is a point of exposure. No further evaluation can be done because of insufficient ambient air data, as discussed in the On-Site Contamination part of the Environmental Contamination and Other Hazards section. On-site workers or residents might be exposed to volatile chemicals via the soil gas pathway. Although the information needs verification, it indicates exposure to volatile organics.
Surface Water Pathway
Surface water represents a potential exposure pathway because four of the five elements that form a completed pathway exist. The missing element is the information about the level of contaminants.
Surface water drainage may follow the railroad tracks transporting surface contaminants off site. During the site visit, residents reported that runoff from the site and overflow from waste-water ponds flowed into businesses west of the site. Concern was expressed about the possible health effects from those incidents.
Springs flow west under Interstate 15 to the remnants of Warm Springs Lake, which is a large wetlands ½ mile west of the Petrochem site. The springs remain frost-free year around and are a valuable fresh water resource in an otherwise high saline environment. The wetlands host many species of game birds that may later be consumed by humans.
The significance of this pathway is unknown because there are no sampling data from the areas where the runoff and overflows occurred nor from any surface water bodies. Because of insufficient information, the surface water pathway cannot be further evaluated.
Groundwater represents a potential exposure pathway because four of the five elements that form a completed pathway exist. The missing element is the lack of a point of exposure (i.e., there are no known private drinking water wells in the Petrochem area).
The alluvial aquifer in the site vicinity is unconfined and consists of clay, silt, and fine sand. It has a relatively low permeability and is seldom used as a water supply due to poor water quality. Shallow monitoring wells indicate that depth to groundwater is 10 to 30 feet below ground surface. Groundwater contamination has the potential to migrate west from the Petrochem site because of the warm springs, which flow beneath the site.
The geologic formations comprising the Wasatch Mountain Range consist predominantly of well-compacted dolomites and limestones. Groundwater flow is directed toward the Salt Lake Valley and Salt Lake. There is a confining layer between the shallow alluvial aquifer and the deeper aquifer; however, it is discontinuous within a 2-mile radius of the site (11). Therefore, the aquifers may be interconnected and the potential exists for contaminants to migrate to the deeper potable aquifer.
There are five municipal wells within a 4-mile radius of the site. They draw groundwater from the deep confined aquifer that has not been tested for contaminants from the site. The closest municipal well is 2.5 miles from Petrochem/EkoTek. Approximately 6,428 people are served by community wells within a 2-mile radius of the site (3). Although drinking water is drawn from the deep aquifers, shallow groundwater is used for irrigation and livestock watering (9). The potential exists for human exposure to any contaminated groundwater.
Approximately 200 private drinking water wells exist within a 4-mile radius of the site, but none within 1 mile. None of the private wells have been sampled for site contaminants. Because there is insufficient off-site data, this exposure pathway can not be further evaluated.
Worker Waste Material Pathway
The waste material on-site represents a potential exposure pathway because four of the five elements that form a completed pathway exist. The missing element is information about the level of contaminants. Workers may have been exposed if they did not use protective clothing and equipment. Since there is insufficient information on contaminant levels, ATSDR cannot further evaluate the worker waste material pathway.
There are no environmental data available on the food chain exposure pathway. Although there are several contaminants from Petrochem/EkoTek that could bioaccumulate, they are unlikely to bioaccumulate at levels of health concern because the chemicals were not used on crop fields or in areas where animals graze. Suitable habitats for game birds exist near the Petrochem site (8, 10). Even if contaminants are available to wildlife, the occasional consumption of wildlife is unlikely to result in health effects.
As discussed in the Pathways Analyses section, soil and ambient air represent completed exposure pathways. The contaminants of concern in the soil exposure pathway are arsenic, barium, beryllium, cadmium, chromium, lead, manganese, mercury, vanadium, PCBs, chlordane, dieldrin, bis(2-ethylhexyl)phthalate, di-n-butyl-phthalate, pentachlorophenol, and heptachlor epoxide. As mentioned in the preceding section, the limited number of off-site soil samples introduces additional uncertainty into the evaluations in this section.
Benzene is the contaminant of concern in the ambient air pathway. The site is only one of several possible sources. As discussed in the Pathways Analyses section, the limited scope of air monitoring precludes further evaluation of this pathway. The potential exposure pathways listed in Table 7 of Appendix B were eliminated from further evaluation in the preceding section.
The Toxicological Evaluation, in this section, will cover possible health hazards from exposure to contaminants of concern in the soil. Community health concerns will be addressed in the Community Health Concerns Evaluation section. As mentioned in the Health Outcome Data part of the Background section, no health outcome data were obtained. The reasons for this are described in the Health Outcome Data Evaluation section.
The toxicological evaluation in a public health assessment is a comparison of the exposure dose for those people in an exposure pathway to ATSDR's Minimal Risk Levels (MRLs) or EPA's Reference Doses (Rfd). The exposure dose is the maximum amount per day, based on the available sampling data, that one might take into their body. The MRLs and Rfds are estimates of daily human exposure to a contaminant below which noncarcinogenic adverse health effects are unlikely to occur (16). That means that any exposure dose below the appropriate MRL or Rfd does not represent a hazard to human health. However, for exposure doses above a MRL or Rfd, there is a wide zone of uncertainty above the MRL or Rfd whether adverse health effects will occur. Therefore, a review of the toxicological literature is done to determine whether the specific exposure situation represents a hazard to public health. The methodology for calculating the exposure doses is described in Appendix D.
The risk of carcinogenic health effects is also evaluated in this section. The limitations and methodology for the carcinogenic evaluation are described in Appendix D.
The Possibility of Health Consequences
The results of the comparisons of exposure doses to health guidelines are in Table 9, Appendix D. None of the adult exposure doses for the contaminants of concern exceeded the health guideline for the contaminant, so adverse health effects are unlikely to occur in adults. The exposure doses for children and pica children exceeded the health guideline for arsenic, barium, cadmium, bis(2-ethylhexyl)phthalate, PCBs, and heptachlor epoxide. The exposure doses for pica children exceeded the health guideline for chromium, manganese, mercury, vanadium, chlordane, di-n-butyl phthalate, dieldrin, and pentachlorophenol. The exposure doses for beryllium for adults, children, and pica children did not exceed the health guideline.
Cancer risk from ingestion of contaminated soil was calculated for beryllium, PCB, chlordane, dieldrin, bis(2-ethylhexyl)phthalate, di-n-butyl-phthalate, pentachlorophenol, and heptachlor epoxide. See Appendix D for a description of how the cancer risk was calculated. The calculated maximum risk from 70 years of daily ingestion of soil contaminated with the maximum concentrations of those chemicals does not represent an increased risk of cancer. Because risk calculations could not be done for arsenic and chromium, possible carcinogenic effects for them will be discussed further.
The possibility of health consequences due to exposure doses is described in the following paragraphs. Exposure to arsenic, cadmium, or barium in off-site soil may result in adverse health consequences under certain circumstances. However, those conclusions are based on the highest levels of the contaminant found in residential soil south of the site. Thus, they may not be indicative of the consequences of ingesting soil from other areas in Swedetown because the levels may be higher, lower, or unknown. Also, as mentioned in the Pathways Analyses section, the limited nature of sampling makes those conclusions uncertain.
Health assessors determine health consequences by comparing the exposure dose to the results of human epidemiologic evaluations of exposure to a chemical. If human evaluations are not available, then information from properly conducted animal studies are used. The type of data used for an evaluation is indicated for each chemical.
Adverse health effects may occur in children who ingest large amounts of soil (pica-5 grams of soil/day or more) contaminated at the maximum concentration, but not in other children or adults. This is based on the results of epidemiologic evaluations of long-term human exposures to arsenic (21). It is unknown whether there are any children in the Petrochem area who display the pica or dirt-eating behavior.
Arsenic is considered a human carcinogen (20, 21). However, ingestion of the maximum levels of arsenic in off-site soils does not represent a risk for carcinogenic effects. This conclusion is based on a comparison of the exposure dose for adults to the lowest observed effect level observed in epidemiologic investigations of human exposures (21).
While arsenic levels found in the Swedetown area may cause health effects in pica children, those levels both on and off site in the Petrochem area are typical for the Salt Lake City area. Arsenic, therefore, is not considered site-related and neither are the possible adverse health effects due to ingestion of arsenic-contaminated soil.
Adverse health effects may occur in children based on a comparison of the exposure doses to the results of the animal studies (22). There is a great deal of uncertainty in this conclusion because of the limited number of samples, and from the difficulty in predicting health effects observed in animals and humans.
Adverse health effects may occur in children who ingest large amounts of soil (pica-5 grams of soil/day or more) contaminated at the maximum concentrations of cadmium in on-site and residential soil. For the maximum concentrations in on-site soil, the exposure dose for pica children was 10 times greater than the level in which no health effects were observed in long-term human exposures (23). For the maximum concentrations in residential soil, the exposure dose for pica children was about the same as the level in which no health effects were observed. For non-pica children, the exposure dose for on-site soil was three times less than the level in which no health effects were observed, and 23 times less for residential soil.
While adverse health effects are possible, it is very unlikely that a child could have frequented the site long or often enough to ingest five grams of soil a day. Access to the site is now restricted. It is unknown whether there are any children in the residential area near Petrochem who display pica behavior. The exposure dose for pica children is about four times less than the level in which the adverse health effects were first observed in humans (23).
Health effects are unlikely to occur from exposure to the maximum levels of chromium in residential soil in the Petrochem area based on animal studies (24). The exposure dose for pica children was 10 times lower than the level in which no health effects were observed in long-term animal studies (24).
Chromium is considered a human carcinogen for the inhalation route of exposure, but not for ingestion (24). Therefore, ingestion of chromium-contaminated soil does not represent a risk for carcinogenic effects.
Three literature reviews have evaluated the relationship between concentrations of lead in soil and blood lead levels in children (25-27). All three concluded that soil lead levels of 1000 parts per million (ppm) would increase concentrations in blood from 0.6 to 65 micrograms/deciliter (µg/dL) with an average increase of 4-5 µg/dL. The wide range was due to different sources of lead, exposure conditions, and exposed populations. The health effects associated with such an increase depend partly on the existing body burden of lead.
Actual health effects depend on factors such as the age and nutritional status of the child contacting the soil, the frequency of contact, the rate of soil ingestion, the type of lead, and the characteristics of the soil. The limited nature of the sampling and the fact that only one of nine samples had detectable levels preclude making any conclusions about possible health consequences from ingesting lead.
Adverse health effects do not appear possible from exposure to the maximum levels of manganese in residential soil based on animal studies (28). The exposure dose for pica children was 100 times lower than the level in which health effects were observed in long-term animal studies (28).
Health effects do not appear possible from exposure to the maximum levels of vanadium in Swedetown residential soil based on animal studies (29). The exposure dose for pica children is 50 times lower than the level in which no effects were observed in animals (29).
Polychlorinated Biphenyls (PCBs)
Studies of exposed workers clearly indicate that PCBs can affect the liver, skin, and eyes, especially after long-term exposures (30). There is some evidence that associates PCB exposure in workers with respiratory, gastrointestinal, hematological, muscular and skeletal, developmental, and neurological effects. However, data are not adequate to establish a cause-effect relationship. The routes of exposure in the studies mentioned above were inhalation or dermal exposures rather than ingestion. In addition, exposure levels in the studies were all much higher than those at the Petrochem site.
Data from long-term animal studies were used for this evaluation. The studies indicate that developmental effects occur at levels at least ten times lower than other effects (30).
Noncarcinogenic health effects due to exposure to PCBs in residential soil are unlikely to occur. The levels in which no effects were observed for the three developmental studies of monkeys are at least 10 times greater than the exposure doses for pica children (31-33). Monkeys and humans are very similar in their responses to toxic chemicals, which allows comparisons without adjustment for inter-species differences (34).
Adverse health effects from exposure to the maximum levels of chlordane in residential soil do not appear to be possible based on a comparison of the exposure dose to the no effects levels from animal studies (35). The exposure dose for pica children is 30 times lower than the level in which no effects were observed in animal studies (35).
Adverse health effects from exposure to the maximum levels of dieldrin in residential soil do not appear to be possible based on animal studies (36). The exposure dose for pica children is 70 times lower than the level in which no effects were observed in animal studies (36).
Data from long-term human exposures and animal studies to heptachlor epoxide are not adequate for this evaluation (37). However, results from animal studies in which exposures were 14-365 days long (intermediate) are adequate for this evaluation.
Health effects do not appear to be possible from intermediate length exposures to the maximum levels of dieldrin in residential soil. The exposure dose for pica children is 10,000 times lower than the level in which no effects were observed in animal studies (37).
Data from long-term human exposures to inorganic mercury are not adequate for this evaluation (38). However, results from long-term animal studies are adequate. Health effects do not appear possible from exposure to the maximum levels of mercury in on-site soil. The exposure dose for pica children is 160 times lower than the level in which no effects were observed in animal studies (38). In addition, because those levels are for on-site mercury, it is unlikely that a child could have frequented the site long or often enough to ingest five grams of soil a day. Access to the site is now restricted.
Data from human exposures to bis(2-ethylhexyl)phthalate are not considered adequate for this evaluation, but animal data from long-term exposures are (39). Adverse health effects from exposure to the maximum levels of bis(2-ethylhexyl)phthalate in on-site soil do not appear possible based on a comparison of the exposure dose to the no effects levels from animal studies and the unlikelihood of regular on-site exposure of children. The exposure dose for pica children is 15 times lower and for children is 333 times lower than the level in which adverse health effects were first observed in animal studies (39). In addition, because those levels are for bis(2-ethylhexyl)phthalate on-site, it is unlikely that a child could have frequented the site long and often enough to ingest five grams of soil a day. Access to the site is now restricted.
Data from long-term human exposures and animal studies to di-n-butyl-phthalate are not adequate for this evaluation (40). However, results from animal studies in which exposures were 14-365 days long (intermediate) are adequate for this evaluation. Adverse health effects from exposure of intermediate length to the maximum levels of di-n-butyl-phthalate in on-site soil do not appear possible based on a comparison of the exposure dose to the no effects levels from animal studies. The exposure dose for pica children is 260 times lower than the level in which no effects were observed in animal studies (40).
Data from human exposures to pentachlorophenol are not considered adequate for this evaluation, but animal data from long-term exposures are (41). Adverse health effects from exposure to the maximum levels of pentachlorophenol in on-site soil do not appear possible based on a comparison of the exposure dose to the no effects levels from animal studies. The exposure dose for pica children is 60 times lower than the level in which no effects were observed in animal studies (41).
Mixtures of contaminants
The preceding paragraphs evaluated the possible health consequences from exposure to each of the contaminants of concern in residential soil. Many of the contaminants are simultaneously present in the soil, so exposure includes a mixture rather than individual chemicals. Currently, there is no accepted method for determining possible health effects from chemical mixtures.
In a public health assessment, available health outcome databases are identified for the area near the site. From those data, ATSDR selects health outcomes for further evaluation based on biologically plausibility or community health concerns.
For biological plausibility, the decision to evaluate health outcome data depends on whether a completed exposure pathway exists for a chemical suspected of causing the health outcome of concern. The selection of a noncarcinogenic health outcome is based on a review of the toxicologic literature for that contaminant of concern.
Designating a chemical as a carcinogen (for purposes of health outcome data evaluation) is based on the following:
- classification by the National Toxicology Program (NTP)1 in its Annual Report on Carcinogens as a "known human carcinogen" or "reasonably anticipated to be a carcinogen"; or
- classification by the International Agency for Research on Cancer (IARC)2 as a 1, 2A, or 2B carcinogen; or
- classification by the United States Environmental Protection Agency (EPA)3 as an A, B1, or B2 carcinogen.
A latency period of at least 10 years between exposure and diagnosis has been observed in most studies of human cancer. If exposure began less than 10 years before the latest data available, analysis of health outcome data for cancer incidence or mortality is not likely to be useful, particularly if the exposure level is low.
Even when health outcomes do not meet ATSDR's guidelines for biological plausibility, health outcome data can be evaluated to address community health concerns.
An important factor in requesting health outcome data in any situation is the difference in size between the population at risk of exposure to site contaminants and the smallest population unit for which health outcome data are available. For example, adverse health effects due to a site would likely not be observed if the population at risk is 100 and the population unit for which health outcome data are available is 100,000.
For the Petrochem site, no health outcome data were requested because of the disparity in population size between the Petrochem area and the smallest unit for which data are available.
Community health concerns are addressed as follows:
1. Employees got sick when air emissions from EkoTek were blown onto their place of business. Will there be long-term health effects from this exposure?
- The business owner who raised that concern mentioned that employees became ill several times a
year for 10 years while the petroleum recycling facility operated. Symptoms were relatively mild
and recovery was rapid. Based on that information, long-term health effects are unlikely because
exposures were infrequent. The human body would be able to get rid of nearly all chemicals
received under such circumstances, which would greatly reduce the chance for long-term effects.
2. Was the dust that was raised during the removal a health hazard?
- It might have been a health hazard for those actually performing the removal activities if they did
not use the appropriate protective equipment. Data available to ATSDR are not sufficient to
evaluate the hazard to those living or working in the area around Petrochem. Information is
needed on the number of times that dust was raised, the areas from which dust was raised, and
the direction the wind was blowing during removal.
3. Several members of the same family have a history of various respiratory illnesses. They asked whether those illnesses could be related to Petrochem, another facility (Utah Metal), or other environmental problems in the area.
- A number of respiratory illnesses can be caused or aggravated by environmental contaminants.
The Petrochem site could have been a source of some illness when it was in operation. The
petroleum refining facility south of Petrochem and Utah Metal could be current sources of
4. Can children play in the dirt in our yards?
- Based on the data reviewed in this public health assessment, children can safely play in
residential yards as long as they do not have the habit of eating dirt (pica).
5. Are the vegetables grown in area gardens safe to eat?
- Yes, they are. Small amounts of the contaminants may be on or in the vegetables. Washing will
remove contaminants on the surface of vegetables. The amount of contaminants in the flesh of
the vegetables would be very small given the low levels of contaminants in the soil.
6. Is it safe for employees to work in the areas of those businesses apparently contaminated by materials from the site?
- Assuming that the areas are contaminated, workers can reduce or eliminate their exposure by
washing their hands before eating or smoking. Workers should not stir up the dirt so that it
creates dust that can be inhaled. Working in the area should be safe if employees take such
7. Could Petrochem/EkoTek be the cause of the 21 cases of cancer reported in the last few years among the residents of the 32 households in the Petrochem area?
- Environmental contaminants such as those that were released from EkoTek/Petrochem and other
facilities could cause specific types of cancer. In order to know whether the facilities could be
the cause of some of the cancers in the Petrochem area would require information on the age,
length of residence, type of cancer, and date of diagnosis of each cancer patient. Data would also
be needed on the number and age of the persons who lived in the area when the cancer cases
occurred. The data would determine whether there is more cancer in the Petrochem area than
what is expected according to the cancer rate for Salt Lake City. If an excess of cancer were
confirmed then identification of possible causes including environmental contaminants would
then be done. Identifying, obtaining, and evaluating the above described data goes beyond the
scope of a public health assessment.
As described in the Recommendations section of this public health assessment, it has been determined that a health statistics review and community health investigation are needed to address concerns about cancer.
In addition, the Utah Department of Health's Bureau of Epidemiology and the Utah Cancer Registry study cancer clusters throughout the state. They may be able to address this concern about cancer. For more information, contact the Bureau of Epidemiology.