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PRELIMINARY PUBLIC HEALTH ASSESSMENT

STAUFFER CHEMICAL COMPANY/TARPON SPRINGS
TARPON SPRINGS, PINELLAS COUNTY, FLORDIA


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

In this section, we review the environmental data collected at this site. We evaluate the adequacy of the sampling that has been conducted, select contaminants of concern, and list the maximum concentration and frequency of detection of the contaminants found in various media. The maximum concentrations found are then compared to background levels and to standard comparison values. The following comparison values are used in the data tables:

    1. CREG--Cancer Risk Evaluation Guide--calculated from EPA's cancer slope factors, is the contaminant concentration that is estimated to result in no more than one excess cancer in a million persons exposed over a lifetime.

    2. EMEG--Environmental Media Evaluation Guide--derived from ATSDR's Minimal Risk Level (MRL), which provides a measure of the toxicity of a chemical, is the estimate of daily human exposure to a chemical that is likely to be without an appreciable risk of non-cancerous adverse effects, generally for a period of a year or longer.

    3. LTHA--Lifetime Health Advisory for Drinking Water--is EPA's estimate of the concentration of a contaminant in drinking water at which adverse health effects would not be anticipated to occur over a lifetime of exposure. LTHAs provide a safety margin to protect sensitive members of the population.

    4. MCL--Maximum Contaminant Level--is the contaminant concentration that EPA considers protective of public health over a 70-year lifetime at an exposure rate of 2 liters of water per day. MCLs are regulatory concentrations.

    5. Chronic RfD--Reference Dose--is EPA's estimate of the daily exposure to a contaminant that is likely to cause non-cancerous adverse health effects.

We selected contaminants at this site based on the following factors:

    1. Concentrations of contaminants on and off the site.

    2. Field data quality, laboratory data quality, and sample design.

    3. Comparison of on-site and off-site concentrations with health assessment comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.

    4. Community health concerns.

Identification of a contaminant of concern in this section does not necessarily mean that exposure will cause adverse health effects. Identification serves to narrow the focus of the health assessment to those contaminants most important to public health. When selected as a contaminant of concern in one medium, we have also reported that contaminant in all other media. We evaluate these contaminants in subsequent sections and determine whether exposure has public health significance.

We reviewed the environmental data collected at this site and selected the following chemicals as contaminants of concern:

Antimony Chromium Sulfur dioxide
Arsenic Fluoride Thallium
Beryllium Lead Vanadium
Boron Radium  
Cadmium Radon  

For chromium, the analysis reports did not specify whether chromium metal (chromium 0), trivalent chromium (chromium III) or hexavalent chromium (chromium IV) was detected. Since chromium VI is the most toxic form of the metal, we feel it is most protective of public health to assume the presence of chromium VI and have used the appropriate comparison values throughout this assessment.

In addition to the contaminants listed above, there are several others of concern to the community. Phosphorus pentoxide may have been emitted from the plant while it was in operation. Citizen complaints and one news report of a fire at the plant describe white clouds of fumes coming from the site. Elemental phosphorus produced at Stauffer would have spontaneously ignited to form white-colored clouds upon exposure to the air. However, no environmental data is available upon which to base an assessment of the public health significance of phosphorus pentoxide.

Phosphorus has been detected in on-site surface soil (609-84,800 mg/kg), subsurface soil (ND-68,000 mg/kg), shallow groundwater (10-49,000 ug/L), off-site surface water (ND-40,000 ug/L) and sediment (31-4,600 mg/kg) (Boison 1987, McClellan 1987a and b, Harris 1988a-1991a, NUS 1989, Weston 1990). There is insufficient toxicological data available upon which to base an assessment of the public health significance of phosphorus.

The possible presence of uranium at the site is also of concern to the local community. Although no environmental samples have been analyzed specifically for uranium, the results of a gamma survey are consistent with the presence of phosphate ore and do not indicate unusual concentrations of radionuclides (Weston 1990).

Polonium 210 is an additional community concern and has been detected in on-site shallow groundwater (ND-80 pCi/L) and off- site surface water (ND-62 pCi/L) (Boison 1987, McClellan 1987a and b, Harris 1988a-1991a). There is insufficient toxicological data available upon which to base are assessment of the public health significance of polonium 210.

To identify industrial facilities that could contribute to the contamination near this site, we searched the 1987, 1988, 1989 and 1990 EPA Toxic Chemical Release Inventory (TRI) data bases. EPA developed TRI from the chemical release information (air, water, and soil) provided by certain industries. The Stauffer plant is in the 34689 zip code area and adjacent to the 34691 zip code area. A TRI search of these two zip codes revealed no industries reporting releases of chemicals found at levels of concern at this site.

In this assessment, the contamination that exists on the site will be discussed first, separately from the contamination that occurs off the site.

A. On-site Contamination

For the purposes of this evaluation, "on-site" will be defined as the area within the fenced boundaries of the main processing plant and the slag storage area to the north (Figure 3, Appendix A).

We compiled data in this subsection from the following sources: the 1988 NUS Corp. groundwater radon data (Donaghue 1988), the 1989 NUS Corp. expanded site investigation (NUS Corp. 1989), the 1990 Weston, Inc. site soil characterization study (Roy F. Weston, Inc. 1990), the 1991 NUS Corp. listing site inspection (NUS Corp. 1991), and the Stauffer Chemical Co. groundwater monitoring plan results (Boison 1987, Harris 1988a-1991a, McClellan 1986-1987b).

Surface Soil

EPA and Stauffer Chemical Co. contractors collected a total of 57 surface soil samples (depth not specified) from various locations on the site between 1988 and 1989 (Donaghue 1988, NUS Corp. 1989, Roy F. Weston, Inc. 1990, NUS Corp. 1991) (Figure 6, Appendix A). A background sample was collected from the northeast corner of the slag disposal area. This area is relatively undisturbed and is considered representative of background conditions on site. Antimony, arsenic, beryllium, cadmium and fluoride were at levels above background and the corresponding comparison values (Table 1, Appendix B). A total of 29 surface samples were also analyzed for radium. The concentrations in 22 of these samples exceeded the background level. For this assessment, these samples were adequate to characterize the on-site surface soil quality.

Subsurface Soil

EPA and Stauffer Chemical Co. contractors collected a total of 45 subsurface soil samples (4 - 15 feet deep) from various locations on the site between 1988 and 1989 (Donaghue 1988, NUS Corp. 1989, Roy F. Weston, Inc. 1990, NUS Corp. 1991) (Figure 7, Appendix A). A background sample was collected from the northeast corner of the slag disposal area. This area is relatively undisturbed and is considered representative of background conditions on site. Antimony, arsenic, beryllium, cadmium and fluoride were at levels above background and the corresponding comparison values (Table 2, Appendix B). A total of 59 samples were also analyzed for radium. The concentrations in 32 of these samples exceeded the background level. For this assessment, these samples were adequate to characterize the on-site subsurface soil quality.

Sediments

EPA and Stauffer Chemical Co. contractors collected a total of 14 sediment samples from various locations on the site between 1988 and 1989 (Donaghue 1988, NUS Corp. 1989, Roy F. Weston, Inc. 1990, NUS Corp. 1991) (Figure 8, Appendix A). A background sample was collected from the eastern half of the slag disposal area. This area is relatively undisturbed and is considered representative of background conditions on site. Arsenic, cadmium, and chromium were at levels above background and the corresponding comparison values (Table 3, Appendix B). Nine sediment samples from the on-site lagoons were also analyzed for radium. The concentrations in all these samples exceeded the background level. For this assessment, these samples were adequate to characterize the on-site sediment quality.

Shallow Groundwater

Between 1985 and 1989, EPA and Stauffer Chemical Co. contractors collected a total of 158 shallow groundwater (less than 35 feet deep) samples from monitoring wells installed at various locations on the site (Boison 1987, Harris 1988a-1991a, McClellan 1986-1987b, Donaghue 1988, NUS Corp. 1989, NUS Corp. 1991) (Figure 9, Appendix A). Background samples were collected from the northeast corner of the slag disposal area. This area is relatively undisturbed and is considered representative of background conditions on site. Background samples were collected from both the upper and lower portions of the surficial aquifer. We consider the samples from the lower portion of the aquifer to represent undisturbed background conditions. Antimony, arsenic., boron, cadmium, chromium, fluoride, lead, thallium and vanadium were at levels above background and the corresponding comparison values (Table 4, Appendix B). A total of 149 samples were analyzed for radon. Of these, 73 contained concentrations above the proposed maximum contaminant level (MCL) of 300 picoCuries per liter (pCi/L). In addition, 131 samples were analyzed for radium. None of these samples exceeded the Florida MCL of 5 pCi/L. For this assessment, these samples were adequate to characterize the on-site shallow groundwater quality.

Deep Groundwater

EPA and Stauffer Chemical Co. contractors collected a total of 5 deep groundwater (greater than 35 feet deep) samples from monitoring wells on site between 1988 and 1989 (Donaghue 1988, NUS Corp. 1989, NUS Corp. 1991) (Figure 10, Appendix A). A background sample was collected from the northeast corner of the slag disposal area. This area is relatively undisturbed and is considered representative of background conditions on site. Arsenic, chromium and fluoride were at levels above background and the corresponding comparison values (Table 5, Appendix B). Ten samples were analyzed for radon. Of these, 8 were at levels above the proposed MCL of 300 pCi/L. In addition, two samples were analyzed for radium. None of these samples exceeded the Florida MCL of 5 pCi/L. For this assessment, these samples are not sufficient to adequately characterize the on-site deep groundwater quality. Only two deep groundwater monitoring wells have been developed on the site. This number is insufficient to assess deep groundwater quality at this site.

B. Off-site Contamination

For the purposes of this evaluation, "off-site" will be defined as the area outside the boundary fences of the Stauffer plant and slag storage area (Figure 3, Appendix A).

We compiled data in this subsection from the following sources: the 1983 report of air monitoring data to the Florida Department of Environmental Regulation (FDER) (Robbins 1983), the 1988 NUS Corp. groundwater radon data (Donaghue 1988), the 1989 NUS Corp. expanded site investigation (NUS Corp. 1989), the 1990 Pinellas county private well monitoring data (Wyatt 1990), the 1990 Weston, Inc. site soil characterization study (Roy F. Weston, Inc. 1990), the 1991 NUS Corp. listing site inspection (NUS Corp. 1991), and the Stauffer Chemical Co. groundwater monitoring plan results (Boison 1987, Harris 1988a-1991a, McClellan 1986-1987b).

Surface Soil

EPA and Stauffer Chemical Co. contractors collected a total of 12 surface soil samples (depth not specified) from various locations on undeveloped property off the site between 1988 and 1989 (Roy, F. Weston, Inc. 1990, NUS Corp. 1991) (Figure 11, Appendix A). No background samples were collected. EPA average soil concentrations for arsenic, cadmium, chromium, fluoride and lead were used as background comparison values. An average soil radium concentration of 1.0 pCi/g published by the Florida Institute of Phosphate Research was also used. These values are listed in Table 6, but may not represent off-site background conditions at this site. Only the concentration of lead exceeded background (Table 6, Appendix B). In addition, two samples were analyzed for radium. The concentrations in both of these samples exceeded the background level. Because of the small number of sample locations and the absence of site-specific background samples, the off-site surface soil quality cannot be fully characterized.

Subsurface Soil

EPA and Stauffer Chemical Co. contractors collected a total of 3 subsurface soil samples (4 - 6 feet deep) from various locations on undeveloped property off the site between 1988 and 1989 (NUS Corp. 1989, Roy F. Weston, Inc. 1990) (Figure 12, Appendix A). No background samples were collected. EPA average soil concentrations for arsenic, cadmium, chromium, fluoride and lead were used as background comparison values. An average soil radium concentration of 1.0 pCi/g published by the Florida Institute of Phosphate Research was also used. These values are listed in Table 6, but may not represent off-site background conditions at this site. Although-fluoride was at a level above background, its concentration did not exceed the corresponding comparison value (Table 7, Appendix B). In addition, five samples were analyzed for radium. None of these samples exceeded the background level. Because of the small number of samples and sample locations, and the absence of site-specific background samples, the off-site subsurface soil quality cannot be fully characterized.

Sediments

EPA contractors collected a total of 24 sediment samples from various locations off the site between 1988 and 1989 (NUS Corp. 1989, NUS Corp. 1991) (Figure 13, Appendix A). Background samples were collected from one location on undeveloped property just off the site and from another several miles away. These areas are relatively undisturbed and are considered representative of background conditions off the site. Although arsenic, chromium, fluoride, lead, thallium and vanadium concentrations exceeded the background levels, only fluoride exceeded its comparison value (Table 8, Appendix B). No off-site sediment samples were analyzed for radium. Except for radium and boron, these samples were adequate to characterize the off-site sediment quality.

Shallow Groundwater

EPA contractors collected a total of nine shallow groundwater samples (less than 35 feet deep) from three monitoring wells off the site between 1988 and 1989 (Donaghue 1988, NUS Corp. 1989, NUS Corp. 1991) (Figure 14, Appendix A). No background samples were collected for comparison. Arsenic, beryllium, cadmium, chromium, fluoride, lead and vanadium were found at levels above the corresponding comparison values (Table 9, Appendix B). Four samples were also analyzed for radon. Two of these samples exceeded the proposed MCL for radon of 300 pCi/L. No off-site shallow groundwater samples were analyzed for radium. Except for radium and boron, these samples were adequate to characterize the off-site shallow groundwater quality.

Deep Groundwater

EPA contractors and the Pinellas CPHU collected a total of 15 deep groundwater samples (greater than 35 feet deep) from five public supply wells, six private wells and two monitoring wells off the site between 1988 and 1990 (Donaghue 1988, Wyatt 1990, NUS Corp. 1989, NUS Corp. 1991) (Figure 15, Appendix A). No background samples were collected for comparison. Arsenic, beryllium, cadmium, chromium, fluoride, thallium and vanadium were found at levels exceeding the corresponding comparison values (Table 10, Appendix B). A total of 20 samples were also collected and analyzed for radon. All these samples contained radon concentrations exceeding the proposed MCL of 300 pCi/L. No off-site deep groundwater samples were analyzed for radium or boron. Because all contaminants of concern have not been analyzed for and the site-specific flow rate and direction of the Floridan aquifer have not been determined, we do not consider the off-site deep groundwater to have been adequately characterized.

Surface Water

EPA contractors and Stauffer Chemical Co. collected a total of 45 surface water samples from the Anclote River at various times between 1987 and 1990 (NUS Corp. 1989, NUS Corp. 1991, Harris 1988a-1991a, McClellan 1987a-b) (Figure 16, Appendix A). One background sample was collected at a point upstream from the site where there is little or no tidal influence. This sample is considered representative of background surface water conditions off the site. The remaining samples were collected in the tidal portion of the river where mixing of upstream and downstream water would occur. Antimony, arsenic, boron, chromium, fluoride, lead, thallium and vanadium were found at levels above the corresponding comparison values (Table 11, Appendix B). A total of 38 samples were also analyzed for radon and radium. No radon concentrations exceeded the proposed MCL of 300 pCi/L and no radium concentrations exceeded the Florida MCL of 5 pCi/L. For this assessment, these samples were adequate to characterize the off-site surface water quality.

Air

Pinellas County collected a total of 30 air samples from its off- site air monitoring station between July and December 1982 (Roabbins 1983) (Figure 17, Appendix A) and analyzed them for sulfur dioxide. Only one sample exceeded the Florida Air Toxics Working List no threat level for sulfur dioxide (Table 12, Appendix B). For this assessment, these samples were not adequate to characterize the air quality at this site. The lack of air monitoring data represents a significant data gap in evaluating the public health hazard of this site.

C. Quality Assurance and Quality Control

We requested but were unable to obtain a data review summary from EPA. In preparing this public health assessment, we relied on the referenced information and assumed that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this public health assessment is determined by the completeness and reliability of the referenced information.

In each of the preceding On- and Off-Site Contamination subsections, we evaluated the adequacy of the data to estimate exposures. We assumed that estimated data (J) and presumptive data (N),were valid. This second assumption errs on the side of public health by assuming that a contaminant exists when actually it may not exist.

D. Physical and Other Hazards

Although we observed numerous physical hazards during the site visit, access to the main plant site and the slag storage area is very closely controlled through fencing and active security patrols. Therefore, we consider the actual risk to trespassers from these physical hazards to be negligible.


PATHWAYS ANALYSES

To determine whether nearby residents are exposed to contaminants migrating from the site, we evaluated the environmental and human components of exposure pathways. Exposure pathways consist of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.

An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. We categorize exposure pathways that are not eliminated as either completed or potential. For completed pathways, all five elements exist and exposure to a contaminant has occurred, is occurring, or will occur. For potential pathways, at least one of the five elements is missing, but could exist. For potential pathways, exposure to a contaminant could have occurred, could be occurring, or could occur in the future.

A. Completed Exposure Pathways

For a summary of the completed exposure pathways at this site, refer to Table 13, Appendix B.

Surface Soil Pathway

Workers on the site have been in the past and are currently exposed to surface soil contamination through direct dermal contact, inhalation of dust, and incidental ingestion of soil. If the site is remediated, remediation workers may also be exposed. Since access to the site is restricted, other community members, including children, are not likely to be exposed through this pathway.

Deep Groundwater Pathway

About three individuals at a nearby business obtained their drinking water from a private deep water well. This business has recently closed. A mobile home park about 0.25 mile southeast of the site uses a private well for irrigation purposes. Casual ingestion of this water may have occurred and may still be occurring. Individuals at these two locations may have been exposed to arsenic in the well water. If the on-site deep water well was used for consumption, then workers and other individuals on the site may have been exposed to arsenic and other contaminants in the past.

Surface Water Pathway

Individuals swimming or coming in contact with water from the Anclote River may have been exposed in the past and may be exposed in the present and future to contaminants in the water. Children and other individuals using the beach/recreation area downstream from the site, as well as skiers and boaters on other parts of the river, may have also been exposed.

Off-Site Sediment Pathway

Individuals coming in contact with sediment in the Anclote River during swimming may have been exposed in the past and may be exposed in the present and future to contaminants in the sediment. Children and other individuals using the beach/recreation area downstream from the site, and individuals who come in contact with sediments from other parts of the river may have been exposed.

Air Pathway

Individuals living within one mile of the site may have been exposed to sulfur dioxide and phosphorus pentoxide fumes emitted from the plant while it was in operation. Those individuals living or working close to the plant may have also been exposed to contaminated dust blowing from the site during periods of high winds.

B. Potential Exposure Pathways

For a summary of the potential exposure pathways at this site, refer to Table 14, Appendix B.

Subsurface Soil Pathway

While subsurface soil on the site is contaminated, this medium is currently inaccessible. However, if this soil is exposed during remediation work, those involved in the remediation could be exposed to this contamination.

Off-Site Surface Soil

Off-site surface soil does not contain any contaminants at a level of concern. However, the available environmental data is inadequate to fully characterize this source of contamination.

On-Site Sediment Pathway

Since the on-site lagoons are no longer filled with water, the sediments in them are accessible to workers on the site. Exposure to the contaminants in these sediments is currently possible and may occur during remediation work.

C. Eliminated Pathways

Shallow Groundwater

Shallow groundwater on and off the site is contaminated.However, the water from the surficial aquifer is not used for any purpose and currently poses no hazard.

Biota

Residents near the site have reported that fishing occurs at a pier about one-eighth mile downstream from the site. Although site-related contaminants are present in the river, none are known to biomagnify and are therefore not likely to occur at levels of concern in fish.


PUBLIC HEALTH IMPLICATIONS

In this section we discuss the health effects on persons exposed to specific contaminants, evaluate state and local health databases, and address specific community health concerns.

A. Toxicological Evaluation

Introduction

In this section, we used standard assumptions to estimate human exposure from incidental ingestion of contaminated soil, incidental ingestion of contaminated water and sediment (during swimming), and ingestion of contaminated groundwater used for domestic purposes.

To estimate exposure from incidental ingestion of contaminated soil, we made the following assumptions: 1) children between the ages of 6 and 18 ingest an average of 200 milligrams (mg) of soil per day, 2) these children weigh about 35 kilograms (kg), and 3) they ingested soil at the maximum concentration measured for each contaminant.

To estimate exposure from incidental ingestion of contaminated surface water during swimming, we made the following assumptions: 1) children between the ages of 6 and 18 swim in the river, 2) they ingest 0.05 liters of water per hour during swimming, 3)each swimming event lasts 1 hour, 4) they swim 72 times per year (3 times/week and 24 week/year), 5) the average weight is 35 kg, and 6) they were exposed to the maximum concentration measured for each contaminant.

To estimate exposure from ingestion of contaminated drinking water, we made the following assumptions: 1) children drink 1 liter (L) of water per day and weigh 10 kg, 2) adults drink 2 L of water per day and weigh 70 kg, and 3) they were exposed to the maximum concentration measured for each contaminant.

To evaluate non-cancerous health effects, ATSDR has developed Minimal Risk Levels (MRL) for contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. ATSDR developed MRLs for each route of exposure, such as ingestion and inhalation, and for the length of exposure, such as acute (less than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). ATSDR presents these MRLs in Toxicological Profiles. These chemical-specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status. In the following discussion, we used ATSDR Toxicological Profiles for the following chemicals:

Antimony Cadmium Radium
Arsenic Chromium Radon
Beryllium Fluoride Thallium
Boron Lead Vanadium

To evaluate the increased risk of cancer from lifetime exposure to site-related contaminants, we use EPA's cancer slope factors. A slope factor is a plausible upper-bound estimate of the probability of a response per unit intake of a chemical. We adjust for less than lifetime exposure and make a qualitative estimate of the increased cancer risk.

Antimony

Workers on the site may have been exposed to antimony via inhalation of dust and incidental ingestion of surface soil, and children swimming in the river may have been exposed to antimony via incidental ingestion of contaminated river water. Although ATSDR has not published an MRL for antimony, we estimate that exposure to on-site surface soil and off-site surface water is unlikely to cause adverse health effects.

Exposure to antimony may affect the liver, cardiovascular system and gastrointestinal tract (ATSDR 1990b). However, the maximum estimated dose from the above sources is about 100 times less than the dose at which no effects were found in animal studies. It is therefore unlikely that any adverse health effects would result from this exposure.

Arsenic

Workers on the site may have been exposed to arsenic via inhalation of dust, incidental ingestion of surface soil and sediments, and consumption of on-site deep groundwater. However, there is no air monitoring data to estimate worker exposure and we do not know the source of drinking water for these workers. There is no ATSDR oral MRL for arsenic (ATSDR 1991b). Our estimate of worker exposure via incidental ingestion of arsenic- contaminated soil and sediments equals the EPA chronic oral RfD. Therefore, we do not expect any non-cancerous health effects in workers from incidental ingestion of contaminated soil and sediments.

Arsenic is a known human carcinogen. Incidental ingestion of arsenic-contaminated soil and sediments by site workers since the 1950's could result in a "low" to "moderate" increase in skin cancer. ATSDR defines this level of increase to mean that after 70 years, at most, an additional five cancers may occur for every 10,000 persons exposed. This exposure would increase the number of expected cancers during the lifetime of these 10,000 persons from 2,500 to 2,505. Because the number of Stauffer employees is much lower than this, it is unlikely that they will develop cancer from their exposure. However, because of this theoretical increase in the rate of cancer, this exposure is considered unacceptable.

Individuals off-site may have been exposed to arsenic via incidental ingestion of surface water and consumption of deep groundwater. These exposures are unlikely to cause-non-cancerous health effects. People who used water with similar arsenic concentrations in their houses for 10 years did not suffer any gastrointestinal, circulatory, dermal, or nervous system effects (Harrington et al 1978, Southwick et al 1981). There would also be no apparent increase in the risk of cancer from this exposure.

Arsenic has been found in off-site deep groundwater monitoring wells at concentrations higher than those in off-site private wells. It is therefore possible that arsenic may be found at higher concentrations in drinking water wells near the site in the future.

Beryllium

Workers on the site may have been exposed to beryllium via incidental ingestion of surface soil and by inhalation of dust. Adverse health effects are unlikely from incidental ingestion of beryllium in the surface soil.

The estimated daily dose of beryllium from ingestion of contaminated soil is less than the ATSDR chronic MRL. Dermal contact with beryllium may cause skin irritation, but beryllium is not readily absorbed through intact skin. Inhalation of beryllium can cause lung cancer and other respiratory illnesses (ATSDR 1988); however, no information is available to allow us-to estimate the level of exposure by this route.

EPA detected beryllium in off-site shallow and deep groundwater monitoring wells indicating that beryllium could appear in drinking water wells in the future. EPA did not detect beryllium in off-site soil or in the river.

Boron

Children and other individuals swimming in the Anclote River may be exposed to boron via incidental ingestion of contaminated water. However, this exposure is unlikely to cause adverse health effects.

The estimated daily dose of boron from incidental ingestion of river water during swimming is less than the ATSDR intermediate MRL. A chronic MRL is not available. Boron may produce adverse effects on the nervous system, kidneys and liver. However, exposure to boron at the concentrations found in the river water is unlikely to cause adverse health effects. Boron is not readily absorbed through intact skin and is not known to cause cancer (ATSDR 1992a).

EPA did not analyze on- and off-site soil and sediment samples or off-site groundwater samples for boron.

Cadmium

On-site workers may have been exposed to cadmium via incidental ingestion of surface soil and sediment,, and by inhalation of dust. However, incidental ingestion of soil and sediment is unlikely to have caused adverse health effects.

The estimated daily dose of cadmium from incidental ingestion of soil and sediment on site is less than the ATSDR chronic MRL. ingestion of cadmium may produce kidney and liver damage. However, ingestion of cadmium is not known to cause cancer. Cadmium does cause cancer when inhaled (ATSDR 1991c). However, there is no information available for us to estimate the amount of exposure to cadmium that could occur from breathing contaminated dust.

Cadmium was not detected in drinking water wells off-site. However, it was found in shallow and deep groundwater monitoring wells indicating that it could appear in drinking water wells in the future. Cadmium was not detected in water from the river.

Chromium

On-site workers may have been exposed to chromium via incidental ingestion of sediments and consumption of drinking water from on-site wells. Individuals swimming in the Anclote River may be exposed to chromium via incidental ingestion of contaminated water. However, these exposures are unlikely to have caused adverse health effects.

The maximum estimated daily dose of chromium in children from ingestion of deep groundwater is at least 10 times less than the dose at which no effect has been found in animal studies. An ATSDR chronic MRL for chromium is not available. Exposure to chromium may cause liver and kidney damage (ATSDR 1991d). However, adverse health effects are unlikely since chromium has not been detected in off-site private wells.

Although chromium was detected in the Anclote River, it does not bioaccumulate in aquatic organisms.

Fluoride

On-site workers may have been exposed to fluoride via inhalation of dust, incidental ingestion of surface soil and consumption of drinking water from on-site wells. Individuals swimming in the Anclote River may be exposed to fluoride via incidental ingestion of contaminated water and sediment. However, these exposures are unlikely to have caused adverse health effects.

Fluoride occurs in off-site deep groundwater at a level exceeding EPA's reference dose. An ATSDR chronic MRL for fluoride is not available. Consumption of this water over a lifetime could result in damage to teeth and bones (ATSDR 1991a). However, fluoride has not been detected in-private wells near the site at a level of concern. Therefore, unless fluoride appears in private wells at increased concentrations in the future, no adverse health effects are likely.

Lead

Individuals swimming in the Anclote River may be exposed to lead via incidental ingestion of contaminated water. Although ATSDR and EPA have no lead exposure guidelines (MRLs or RfDs) for comparison (ATSDR 1990a), we estimate that this exposure is unlikely to have caused adverse health effects.

Although the maximum concentration of lead in the river water (0.15 mg/L) is ten times greater than the Florida drinking water standard (0.015 mg/L), we estimate the annual volume of water ingested during swimming in the river is 100 times less than the annual volume of water ingested from drinking water sources. Therefore, we estimate the dose of lead from incidental ingestion during swimming in the river is about ten times less than the dose from drinking water at the Florida standard.

Lead has not been detected in deep groundwater. However, it has been detected in shallow groundwater both on and off the site. Therefore, it is possible that lead may appear in deep groundwater drinking water wells in the future.

Radium

On-site workers may have been exposed to radium via incidental ingestion of soil and inhalation of dust. While adverse health effects are not likely from ingestion exposure, there is insufficient information available for us to determine if adverse health effects could result from inhalation exposure.

EPA has set occupational Annual Limits of Intake (ALI) for radium exposure by ingestion and inhalation. Long-term exposure to radium can result in anemia, necrosis of the jaw and bone cancer (ATSDR 1990c). Radium has been detected in on- and off-site surface soil at levels above background concentrations. These levels are at least 100 times less than the EPA ALI for ingestion of radium. However, no information is available to allow us to estimate the level of exposure by inhalation of dust.

EPA did not analyze off-site groundwater or river sediment for radium.

Radon

Workers on-site and individuals with private wells off-site may have been exposed to radon via consumption of contaminated deep groundwater. However, it is unlikely that exposure at the maximum concentration could cause adverse health effects.

Although ATSDR and EPA have no exposure guidelines (MRLs or RfDs) for radon in water, EPA has set a recommended exposure limit of 4.0 pCi/L of radon in air. The primary health risk from radon is an increase in the chance of lung cancer from inhalation exposure. There are no known health risks from consumption of radon in water (ATSDR 1990d). However, radon that outgasses from water will contribute to the radon level in indoor air. About 10,000 pCi/L of radon in water are required to increase the indoor air level by 1.0 pCi/L. Thus, the maximum contribution to indoor air levels from deep groundwater at this site would be less than 0.5 pCi/L. We estimate that this increase would not significantly increase the risk of cancer.

Sulfur Dioxide

Workers on the site and individuals off-site within about one- half mile may have been exposed to sulfur dioxide in the air. Since there are insufficient environmental data available to enable us to estimate the exposure to sulfur dioxide and very little toxicity information is available (Sittig 1985), we cannot determine the health risk to persons who may have been exposed.

Thallium

Individuals swimming in the Anclote River may be exposed to thallium via incidental ingestion of contaminated water. However, the maximum concentrations are unlikely to cause adverse health effects.

There is no ATSDR chronic MRL available for thallium. However, the estimated daily dose of thallium from incidental ingestion of contaminated river water is less than the dose at which no effect was found in animal studies. Although exposure to thallium can affect the nervous system, lungs, heart, liver and kidneys, the extent and severity of its effects at low concentrations are unknown. Thallium is not known to cause cancer (ATSDR 1992b). The maximum estimated dose from incidental ingestion during swimming is so low that adverse health effects are unlikely.

Thallium has not been detected in off-site private wells. However, it has been found in on-site shallow groundwater and off-site deep groundwater monitoring wells. Therefore, it is possible that thallium may appear in private wells in the future.

Vanadium

Individuals swimming in the Anclote River may be exposed to vanadium via incidental ingestion of contaminated water. However, the maximum concentrations are unlikely to cause adverse health effects.

The estimated daily dose of vanadium from incidental ingestion of contaminated water during swimming is less than the draft ATSDR intermediate MRL. A chronic MRL is unavailable. Vanadium has not been identified as causing cancer. Therefore, incidental ingestion of vanadium during swimming would be unlikely to cause adverse health effects. Since vanadium does not pass readily through the skin (ATSDR 1992c), adverse health effects from skin exposure are also unlikely.

B. Health Outcome Data Evaluation

Guided by community health concerns in the population living near the site, Florida HRS epidemiologists conducted an evaluation of cancer and birth defect incidence in this area. Since cancer and birth defect information was not available by zip code, an analysis was performed for the entire counties of Pasco and Pinellas. The site is in Pinellas county but borders Pasco county (Figure 2, Appendix A). The rates of birth defects and the incidence of cancer in these counties were compared with those for the state of Florida.

The number of birth defects in both counties was very small and was not elevated compared to the overall state rates. in addition, none of the contaminants at the Stauffer site is known to cause birth defects (Hurt 1993a). The rates of individual cancers, in particular lung and brain cancer, for the state and both counties are quite similar.

Because cancer and birth defect information for the zip code areas closest to the site are not available, we cannot determine the actual rates in the communities near the site. The available information, however, indicates that there is no unusual incidence of cancer or birth defects.

C. Community Health Concerns Evaluation

We have addressed each community health concern as follows:

  1. Can contamination from the site cause brain cancer in people living close to the site?

    None of the contaminants of concern at this site are known to contribute to the incidence of brain cancer. Examination of the Florida cancer registry by HRS epidemiologists has not revealed any elevated rates of brain cancer in Pinellas or Pasco counties.

  2. Are contaminants leaching into the groundwater from the site and entering nearby private and public wells?

    Contaminants occurring on the site also occur in shallow and deep groundwater monitoring wells and two private drinking water wells off-site. It is therefore possible that these contaminants may appear in private off-site drinking water wells in the future.

  3. Were radioactive materials produced when the plant was operating and do they continue to contaminate the site?

    There is no evidence that radioactive materials were purposely extracted during the processing of phosphate ore for elemental phosphorus. Uranium and radium occur naturally in phosphate ores. Although no environmental samples have been analyzed for uranium, the results of the gamma survey of the site are consistent with the presence of phosphate ore and do not indicate unusual concentrations of radionuclides, including uranium. Radium has been found in on-site soil at levels above background but does not occur in on-site groundwater at a level of concern. However, no off-site groundwater samples have been analyzed for radium. Therefore, we cannot estimate the exposure from this source.

  4. Can dust blowing from the site carry contamination into the community or the nearby river?

    No on-site surface soil contaminants occur at a level of concern in off-site surface soil. However, antimony, arsenic and fluoride occur in both on-site surface soil and the Anclote River. The source of this contamination may be dust from the site, stormwater runoff or other, unknown, sources.

  5. Have children at the elementary school north of the site been exposed to contamination from the site?

    Since the school is supplied by public water, drinking water would not be a source of exposure to children. Of the contaminants of concern found at this site, only lead and chromium have been analyzed for in surface soil at the school. Neither was detected at a level of concern. However, we have no information about the other contaminants of concern in the soil or about any contaminants in the air or air-borne dust. Without this information, we cannot estimate the exposure from these sources.

  6. When the plant was in operation, people near the plant or using the river frequently reported being exposed to clouds of white fumes that produced respiratory distress. What other adverse health effects could occur from this exposure?

    These clouds of white fumes are most likely phosphorus pentoxide emissions from the site. Local residents may also have been exposed to sulfur dioxide from the plant. However, there is no air monitoring data available to enable us to determine if exposure to these emissions represented a public health hazard.

  7. What has happened to the 900 drums of calcined phosphate sand buried on the site and what hazard do they represent?

    In their current location, the material in these drums is not a hazard. If intact drums are recovered during remediation work, they are a possible fire hazard. Phosphorus migrating into the groundwater would be converted into a dilute phosphoric acid solution that is not a health hazard.

  8. Can exposure to contaminants in the air produce emphysema or lung cancer in workers at the plant?

    Several contaminants detected in the soil above ATSDR comparison values may produce lung cancer. Workers at the plant may have been exposed to these contaminants in dust on the site. Evaluation of lung cancer incidence in Pinellas and Pasco counties by Florida HRS epidemiologists has not revealed any elevated rates of lung cancer. Without air sampling data, however, we cannot predict the health hazard resulting from breathing dust generated on the site.

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