PUBLIC HEALTH ASSESSMENT
SOLITRON MICROWAVE
PORT SALERNO, MARTIN COUNTY, FLORIDA
Solitron Microwave, on Cove Road in Port Salerno, Martin County, Florida, covers approximately 20 acres. Between 1963 and 1987, the General R.F. Fitting Company and Solitron Devices, Inc. manufactured miniature electronic equipment. The facility discarded wastewater in a ditch, in an on-site percolation pond and in underground drains. The site is in a mixed residential and commercial area. On-site surface water, sediment, soil and groundwater are contaminated with metals and organic chemicals. Off-site groundwater is contaminated with metals and organic chemicals.
In this public health assessment, we evaluate the potential for illnesses to be caused by exposure to contaminated surface soil, surface water, sediment, and groundwater. Off-site groundwater and on-site soil are completed exposure pathways. On-site groundwater is a potential exposure pathway. Surface water and sediment are not completed exposure pathways.
Currently the site is a potential public health hazard because people could be exposed in the future to contaminated on-site groundwater. If people install new on-site wells or if contamination moves offsite to private or municipal wells, they could be exposed to the contaminated groundwater. The levels of volatile organic chemicals (VOCs) found in private well water in the past are unlikely to have caused illness. The buildings on this site are not secure and there are no hazardous waste warning signs.
We recommend the Martin County Health Department continue to identify and sample private wells northeast of the site. We recommend government officials continue to inform residents northeast of the site of the potential public health threat resulting from contamination from the site migrating to private or municipal wells. We recommend the maintenance of security around the site to reduce the risk of physical hazards and post hazardous waste warning signs.
In this public health assessment, the Florida Department of Health (FDOH) in cooperation with the Agency for Toxic Substances and Disease Registry (ATSDR), evaluates the public health significance of the Solitron Microwave site. Specifically, FDOH decides whether illness is possible from exposure to levels of contaminants at the site and recommends actions to reduce or prevent these illnesses. FDOH has not previously reviewed any data for this site. The Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA or Superfund) authorizes the ATSDR to conduct public health assessments at hazardous waste sites. The ATSDR, in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services.
A. Site Description and History
In March 1998, the Environmental Protection Agency, (EPA) proposed the Solitron Microwave site to the Superfund National Priorities List. Solitron Microwave, on Cove Road in Port Salerno, Martin County, Florida, encompasses approximately 20 acres (See Figure 1). Beginning in 1963, the General R.F. Fitting Company occupied the site. They manufactured electronic equipment. In 1968, Solitron Devices, Inc. bought the site and until 1987 also manufactured miniature electronic equipment (EPA 1998a). From about 1964 to 1970, the facility discarded wastewater in the Cove Road ditch, a "more or less natural ditch" which ran into the north-south creek, east of the building. After 1971, the ditch flowed beneath the Cove Road by way of a culvert (FDER 1991). They treated wastewater in the wastewater treatment area, behind the building, then discarded it in an on-site percolation pond. They discarded water from sinks inside the building in underground drains in the northeast part of the site (EPA 1998a). Currently, the site is vacant (See Figure 2 & 3).
In 1983, Florida Department of Environmental Protection (FDEP) site inspectors noted leaking pipes and contaminated soil. In February 1985, the EPA conducted a Site Screening Investigation. They found organic and metal compounds in the groundwater, surface water, soil and sediment. (EPA 1998a). In 1989, the FDEP investigated groundwater and soil contamination in the Contamination Assessment Report. They found organic compounds primarily in the surficial aquifer, above 75 feet. They did not find soil contamination above screening levels (FDER 1989).
In late 1988 and early 1989, the EPA found elevated levels of perchloroethylene, trichloroethene, trichloroethane, xylene, acetone, vinyl chloride, methylene chloride and 1,1-dichloroethene in the surficial aquifer under the site above the maximum contaminant levels (MCLs; EPA 1998a). In 1990, Solitron dug up sediment from the pond. They piled itand covered it with a plastic sheet, however, records do not indicate if the sediment was piled and covered onsite or offsite (EPA 1998b).
In February 1991, FDEP investigated on-site and off-site contamination in Phase II of the Contamination Assessment Report for the Solitron Microwave Site. They found groundwater contaminated with VOCs moved north and offsite and north to Grant Street and east just beyond Ebb Tide Avenue (FDER 1991).
Between 1991 and 1993, the Martin County Health Department (CHD) periodically sampled nearby private wells. They found vinyl chloride in six out of twenty-two of these wells above the MCL (Washam 1998). From February 1992 to April 1993, Solitron provided bottled water to nearby residents with contaminated private wells (EPA 1998). In 1994, they also funded a water main to the neighborhood and municipal water hookups for private wells with levels of contaminants above the MCL (FDER 1991).
In 1995, the Martin CHD continued periodic sampling fifty of nearby private wells. They identified groundwater contamination north of Cove Road but not south of Cove Road (personal communication with Martin CHD Environmental Health Director, January 15, 1999). Residents with contaminants above the MCL in their private well water were hooked up to municipal water (Washam 1998).
In August 1998, the Martin CHD found two more private wells out of twenty-nine wells had vinyl chloride above the Maximum Contaminant Level (MCL). They found trace levels of vinyl chloride or other chemical and metals in sixteen wells. In December 1998, the Martin CHD requested FDEP connect these homes with vinyl chloride in their well water above the MCL to a municipal water supply. The Martin County Health Department plans to periodically resample private wells and other homes in the area (Letter to Russ Blackburn from Robert Washam 1998).
In 1998, the EPA investigated three areas of potential contamination: the wastewater treatment area, the percolation pond and the septic fields (See Figure 4). The surface water from the pond is contaminated with nickel. The surficial aquifer under the northern portion of the site is contaminated with organic chemicals and metals. Metals, however, are also present in background groundwater and soil samples (EPA 1998a).
On March 3, 1998, the EPA proposed the site to the National Priorities List as a Superfund Site.
Julie Smith of the FDOH, Bureau of Environmental Toxicology visited the site June 18, 1998. The site is on Cove Road in a mixed residential and commercial area of Port Salerno. The property is vacant and a chain link fence lines the front of the property. The site is not posted with warning signs. A path leads from the sidewalk around the fence onto the property. The building onsite is abandoned and the door does not lock. Trash, clothes, and graffiti are evidence people have access to the building and homeless people might be living onsite. The property around the building is grassy with palm trees and shady dirt roads. People frequent the area as evidenced by trash and clothes. Several dirt paths lead onto the property. The pond in front of the building is swampy and home to turtles.
A church and a junk yard are directly across the street. A neighborhood of single family homes with some having private wells is across the street to the northeast. The neighborhood is middle to low income. A swampy creek is on the east edge of the neighborhood. The Lil Saints gas station is north east of the site (See Figure 3).
C. Demographics, Land Use and Natural Resource Use
About 6,760 people live within one mile of the site. Five-thousand and forty-four residents are white and 525 are black. Six-hundred and sixty-eight are less than six years old and 1,139 are over the age of sixty-five. There are 1,531 women of childbearing age (Bureau of Census 1990).
A 1989 survey identified ten public wells, two irrigation wells and two U.S. Geological Survey wells within a ½ mile radius of the site (FDER 1989).The Martin County Utilities has five wells within 4000 feet south of the facility. They blend water from these five wells with twenty other wells. This system serves about 53,544 people (Kristiansen 1997). There are sixty-four known private wells within a 1 mile radius of the pond serving about 145 people (EPA 1998b). The EPA has sufficient evidence to assume the private wells are in the surficial aquifer (FDER 1989).The surficial aquifer is the principal source of drinking water in Martin County. The surficial aquifer flows north-north east toward the Manatee Pocket - Manatee Creek (EPA 1998b).
We did not evaluate health outcome data for the community around this site. We do not have health-outcome databases capable of searching for effects in such a small population/geographical area.If future environmental investigations find larger areas of exposed populations, we will evaluate health outcome data as considered appropriate.
Some community members are concerned about the quality of their private well water. In June 1999, the FDOH held a public availability session and collected health concerns from nearby residents. These concerns are described in the section Community Health Concerns on page 14.
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
In this section, we review the environmental data collected at the site, evaluate sampling adequacy, and select contaminants posing the greatest threat to health (contaminants of concern). We select contaminants of concern based on the following factors:
We used the following ATSDR standard comparison values (ATSDR 1998a), in order of priority, to select contaminants of concern:
Identifying a contaminant of concern in this section does not necessarily mean that exposure will be associated with illnesses. Identification serves to narrow the focus of the public health assessment to those contaminants most important to public health. We evaluate the contaminants of concern in subsequent sections and decide whether exposure has public health significance.
The on-site groundwater is contaminated with vinyl chloride, 1,1-dichloroethene, perchloroethylene, trichloroethene, barium, beryllium, cadmium, chromium, copper mercury, nickel, selenium, carbon tetrachloride above ATSDR screening levels. Lead, aluminum, and 1,1-dichloroethane were also detected in the groundwater but ATSDR does not have screening values for these compounds (see Table 1). The EPA detected the highest level of chromium in the sample termed the 'background sample' that was collected on-site behind the south-west corner of the Solitron building (groundwater flows north-northeast).
Copper and aluminum were also detected in soil, but ATSDR does not have screening values for these compounds (See Table 2). These metals were above background values (ATSDR 1992).
The surface water from the pond is contaminated with nickel. Sediment from the pond remaining after remediation was not contaminated.
In February 1991, the Martin CHD found contaminated groundwater had moved offsite to the residential area north-northeast of the site. Off-site groundwater is contaminated with vinyl chloride, arsenic, perchloroethylene, trichloroethene, copper and lead above ATSDR screening levels. Aluminum was also detected but ATSDR does not have a screening value for this chemical (See Table 3; Washam 1998).
C. Quality Assurance and Quality Control
In preparing this public health assessment, we relied on the existing environmental data. We assumed consultants who collected and analyzed these samples followed adequate quality assurance and quality control measures concerning chain-of-custody, laboratory procedures, and data reporting. The completeness and reliability of the referenced information determine the validity of the analyses and conclusions drawn for this public health assessment. The available quality assurance and quality control information is presented below.
The FDEP reviewed and approved the 1987 Contamination Assessment Plan and the Quality Assurance Project Plan by Enviropact, Inc.Enviropact conducted the 1989 and 1991 Contamination Assessment Reports for FDEP. FDEP does not require further validation for the Contamination Assessment Reports (Kristiansen 1995).
The Martin County Health Department followed all quality assurance and quality control (QA/QC) procedures for testing of private wells in 1991. The supervisor verified the samples for adherence to protocol and established acceptable QC ranges (Arms 1993).
The Solitron Building doors are not closed or locked and access to the site is not restricted. There are no warning signs around the property. Equipment in the building may present a physical hazard. People may trip over debris inside the dark building.
The amount of contact people have with hazardous substances is essential to assessing the public health significance of a contaminant. Chemical contaminants in the environment have the potential to harm human health, but only if people have contact with those contaminants.
An exposure pathway is the way an individual contacts contaminants. To decide whether nearby residents have contacted contaminants at the site, we looked at the human exposure pathways. An exposure pathway has five elements: The first element is an original contamination source, like an industrial site. The second element is an environmental media, like air or groundwater, that moves contamination from the source to a place where people can contact the contamination. The third element is a place where people could contact the contaminated soil or groundwater, like topsoil or a drinking water well. The fourth element is the exposure route, like drinking contaminated water or touching contaminated soil. The fifth element is a group of people who can potentially come in contact the contamination, like people living or working near the contaminated site.
We eliminate an exposure pathway if at least one element is missing and will never be present. For completed pathways, all five elements exist and exposure to a contaminant has occurred, is occurring, or will occur. For potential pathways, exposure to a contaminant could have occurred, could be occurring, or could occur in the future.
The public health findings for the community surrounding the site are based on identification of past, present, and future exposure pathways. We identified exposure pathways that are significant to public health in this assessment (See Table 4).
A. Completed Exposure Pathways
The site visit revealed evidence of trespassers on the property, gaps in the fence and possibly homeless people living in the buildings. It is likely that in the past, people trespassing on this site or homeless people came into contact with contaminated soil. Since site access is unrestricted, it is likely that site trespassers are currently being exposed. If site access is not restricted, it is likely that trespassers will continue to be exposed in the future.
Nearby residents may have been exposed to chemicals from this site in their well water. The Martin County Health Department has identified private wells with levels of organic chemicals above standards.
B. Potential Exposure Pathways
People could be exposed in the future to chemicals from this site if they drill new wells into the contaminated aquifer onsite.
People could be exposed in the future to chemicals from this site if contaminated groundwater migrates to their existing wells.
C. Eliminated Exposure Pathways
Surface water and sedimentare not likely exposure pathways. It is extremely unlikely that a person would drink from or swim in the on-site ponds with any frequency.
In this section we will discuss how and when people contact contaminants and the public health implications of those exposures. We estimated an exposure dose of each contaminant a child (for potential non-cancer effects) and adult (for potential carcinogenic effects) might receive by coming into contact with contaminated surface soil.
For noncancerous contaminants, we estimate the dose an elementary school child would receive if he or she came into contact with soil almost daily because it is the most conservative exposure scenario. By using the most conservative exposure scenario, we will nonetheless overestimate risk, but we will be sure to protect all individuals, even overtly sensitive individuals, for example, very young and very old people, people with nutritional deficiencies, chronic illnesses, immune system deficiencies or substance abuse.
In surface soil, we estimated the dose that an elementary school child, weighing 24 kilograms (50 pounds), would receive by incidentally eating 200 milligrams of contaminated surface soil or about one-half liter of contaminated water per day, 350 days a year for six years (EPA 1989b).
For groundwater exposure, we estimated the dose for children drinking about one-half liter of water per day. Children represent a sensitive sub population. Exposures that are protective of children are most likely protective of adults.
For carcinogenic compounds, we estimated an exposure dose that an adult, weighing 70 kilograms (150 pounds), would receive over a lifetime (70 years) of incidentally ingesting 100 milligrams of surface soil a day or drinking two liters of contaminated water per day, 350 days out of the year (Risk Assistant, 1994).
To evaluate each contaminant, we compared our exposure estimate with ATSDR and EPA health guidelines. These health guidelines help us screen the contaminants that require further investigation. These values alone, however, cannot determine a particular contaminant's potential health threat. If exposure estimates were less than the health guideline, we did not evaluate the contaminant further. If exposure estimates exceeded the health guideline or if no health guideline existed, we then compared exposure estimates with doses in human or animal studies and described the results.
For noncancerous contaminants, we compared our exposure estimate with health guidelines such as ATSDR's Minimal Risk Level (MRLs) and EPA's Reference Doses (RfDs). RfDs and MRLs estimate the daily exposure dose a person can tolerate without becoming sick over a specified length time (EPA 1989a). We used long-term exposure MRLs before intermediate duration MRLs, if both existed. We used intermediate duration MRLs before short-term exposure MRLs, if both existed, because our exposure estimates are based on a longer term exposure.
For cancerous contaminants, we compared our exposure estimates with EPA's cancer potency factors. We used a potency factor to estimate an upper-bound probability of an individual developing cancer from a lifetime of exposure to a particular level of a potential carcinogen (ATSDR 1992a). These estimates are based on the assumption that there is no safe level of exposure to a carcinogenic contaminant. Each exposure carries some degree of risk, no matter how small. Therefore, we define 'safe exposure' as a reasonable or acceptable degree of risk (for example, one in one million) rather than zero (Williams 1985). To err on the side of safety, these estimates may overestimate the risk associated with cancer. When examining cancer risks, it is important to recognize the background cancer rate in United States is about 25% or 25 in 100 (ATSDR 1993a).If we add a one-in-a million additional cancer risk to the background risk, the risk increases to 25.0001% cancer risk. This means we expect 25.00001 people out of 100 (similarity, 25,000,001 cancers in 100,000,000) in a population will get cancer.
Non-Cancer Section
Onsite
We do not expect any non-cancer illness from exposure to contaminated on-site soil.
We do not expect any non-cancer illness from potentially drinking on-site groundwater contaminated with acetone, lead, aluminum, 1,1-dichloroethene, perchloroethylene, trichloroethene, barium, beryllium, cadmium, copper, mercury, nickel, selenium, carbon tetrachloride or 1,1-dichloroethane. Our estimated dose from all of these contaminants was below their MRL or RfD. For those contaminants without an MRL or RfD, our estimated dose was far below the dose causing illness in humans or animals (ATSDR 1997a, ATSDR 1997b, ATSDR 1992b, ATSDR 1993c, ATSDR 1990, ATSDR 1997c, ATSDR 1997d).
Vinyl chloride and chromium had concentrations were above standard comparison values. Weevaluated these contaminants further.
Vinyl chloride is a colorless gas but it can also dissolve in water. It has other names such as chloroethene, chloroethylene, ethylene monochloride and monochloroethylene. Vinyl chloride at the Solitron Microwave site came from the breakdown of other substances that Solitron used in the manufacturing process (ATSDR 1997e).
We estimated the doseof vinyl chloride that a child would receive if they potentially drank contaminated on-site groundwater. Our estimated dose is above the MRL and 3.3 times higher than the level that caused cellular changes in animal livers. If children drink this water, we would expect cellular changes in their livers. However, there is no evidence anyone drank this water in the past and we do not expect anyone to drink on-site groundwater in the future.
Chromium is a naturally occurring element found in rocks, soil, plants and animals. Certain types of chromium are essential for body functioning (ATSDR 1993b).
We estimated the doseof chromium that a child would receive if they potentially
drank contaminated on-site groundwater. Our estimated dose is slightly above
the level that caused oral ulcer, diarrhea, abdominal pain, indigestion, vomiting,
problems with blood cells and dermatitis in people (ATSDR 1993b). If children
drink this water, we would expect these illnesses. However, there is no evidence
anyone drank this water in the past and we do not expect anyone to drink on-site
groundwater in the future.
Off-site
We do not expect any non-cancer illness from off-site private drinking water contaminated
with lead, aluminum, arsenic, perchloroethylene, trichloroethene, or copper. Our estimated
dose from all of these contaminants was below our Minimal Response Level (MRL) or
EPA's reference dose (RfD). For those contaminants without a MRL or RfD, our estimated
dose was far below the dose causing illness in humans or animals (ATSDR 1997a, ATSDR
1997b, ATSDR 1990).
We do not expect any illness from the levels of vinyl chloride found in private wells. From the highest level of vinyl chloride found in one drinking water well, we estimated the dose that a child would receive. Our estimated dose is 82 times higher than ATSDR's MRL for chronic exposure. This MRL was based on a dose given to rats for almost three months who developed changes in their liver cells (basophilic foci of cellular alteration). This dose is multiplied by 1,000, as a safety factor, to develop the MRL. Our estimated dose is ten times lower than the dose causing cellular changes in animals. Our estimated dose of vinyl chloride is slightly higher than the level people may receive from drinking water from pipes made from PVC (polyvinyl chloride; ATSDR 1997e). Since the dose of vinyl chloride is below the level that caused an effect in animals, since only one well had this high level of vinyl chloride, and since residents with contaminated private wells were given bottled drinking water soon after contamination was identified, we do not expect any illnesses from vinyl chloride in private wells.
Cancer
Onsite
We do not expect any increased risk of cancer from drinking 1,1-dichloroethene, beryllium or carbon tetrachloride- contaminated on-site groundwater. The EPA does not have a potency factor to compare the carcinogenic effects of acetone, lead, aluminum, perchloroethylene, trichloroethene, barium, cadmium, chromium, copper, mercury, nickel, selenium or 1,1-dichloroethane. There is not enough information to assess the carcinogenic potential of these compounds in on-site groundwater.
Scientists found that workers who breathe vinyl chloride can develop a rare type of cancer, angiosarcoma of the liver. There are no cancer studies of people who have ingested vinyl chloride. The EPA classifies vinyl chloride as a human carcinogen. If people drink vinyl chloride-contaminated groundwater from under this site for a lifetime, we would expect a moderately increased risk of liver cancer. It is very unlikely, however, that anyone would drink groundwater from directly under the site.
Offsite
We do not expect any increased cancer risk from arsenic-contaminated private drinking water wells. The EPA does not have a potency factor to compare the carcinogenic effects of lead, aluminum, perchloroethylene, trichloroethene and copper. There is not enough information to assess the carcinogenic potential of these compounds in private drinking water wells in the vicinity of this site.
When we compare our estimated dose of off-site private well water contaminated with the highest level of vinyl chloride found with the EPA cancer potency factor, we estimate that if over a lifetime, they would have a low increased risk of liver cancer. However, there is no evidence people drank vinyl chloride-contaminated private well water for 70 years.
We estimated doses a child would receive if they came into contact with site related contaminants. We expect children would become ill from drinking vinyl chloride and chromium contaminated on-site groundwater. It is, however, unlikely that children would drink this water. We do not expect children to become ill from drinking off-site contaminated groundwater.
Before birth, children are forming the body organs that need to last a lifetime. This is the time when contaminant injury may lead to serious injury or illness. Injury during certain periods of growth and development may lead to malformation of organs (teratogenesis), disruption of function, and premature death. Exposure of the mother leads to exposure of the fetus since some contaminants cross the placental barrier (ATSDR 1998b).
Small children may have greater exposures to environmental contaminants than adults. Pound for pound of body weight, children drink more water, eat more food, and breathe more air than adults. For example, children in the first six months of life drink seven times as much water per pound as the average adult living in the United States. Children's exposure to contaminants in the environment is also greater because they play close to the ground increasing their exposure to contaminants in dust and soil plus contaminants in the air, and they put many things into their mouths. Their hands, toys and other items may have soil and dust containing contaminants from paint, gasoline, vehicle emissions and industrial sources. In addition, children may accidentally wander or deliberately trespass onto or into restricted locations. The obvious implication for environmental health is that children can have much greater "doses" than adults to contaminants that are present in soil, water, or air (ATSDR 1998b).
In June 1999, the FDOH held a public availability session and collected health concerns from nearby residents. In this section, we address each community health concern.
Are properties west of the site contaminated?
Technical studies have shown the contaminated groundwater is moving east, northeast. We do not expect the contamination to move west.
How often are the individual (private) wells tested?
The Martin County Health Department is testing and retesting private wells about every six months.
Has concern passed in the area of those wells tested?
No, the contamination could move into areas that were previously tested.
Is the area being cleaned of chemicals?
The EPA is currently studying the area to develop the best way to manage the site.
Can we have the water lines available with no costs for the line installation because some people are on fixed incomes?
The Florida Statutes say that the Department of Environmental Protection is authorized to hook up private wells to municipal water free of charge to the well owner if they are contaminated above standards called the Maximum Contaminant Levels (MCLs: Personal Communication with the Martin County Health Environmental Health Director June 24, 1999). Contaminants below the MCLs ensure that drinking water is safe for human consumption.
Was our well tested from the well at the pump or at the faucet?
The samples collected by the Martin County Health Department were collected from the faucet.
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