MUNISPORT LANDFILL
NORTH MIAMI, DADE COUNTY, FLORIDA
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
In this section, we review the environmental data. We judge the adequacy of the sampling, select contaminants of concern, and list the maximum concentration and frequency of detection of these contaminants. We then compare the maximum concentration found to background levels and to standard comparison values. We discuss on-site contamination first and off-site contamination second.
We reviewed the environmental sampling data collected at this site since 1975 and selected the following contaminants of concern:
| ammonia | chloromethane | pentachlorophenol |
| benzene | coliform bacteria | polychlorinated biphenyls (PCBs) |
| di(2-ethylhexyl) phthalate | dieldrin | styrene |
| cadmium | lead | vanadium |
| carbon disulfide | methylene chloride | zinc |
We selected these contaminants 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 carcinogenic and noncarcinogenic 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 public health assessment to those contaminants most important to public health. When selected as a contaminant of concern in one medium, we also report that contaminant in all other media. We evaluate these contaminants in subsequent sections and determine whether exposure has public health significance.
In addition to the contaminants of concern listed above, the following chemicals were detected in the ground water at concentrations above selection guidelines:
| arsenic | chlordane | molybdenum |
| barium | chromium | nickel |
| beta-BHC | manganese | strontium |
We eliminated these chemicals from further consideration, however, because ground water is not a likely past, current, or future human exposure pathway. See the Pathways Analyses section for details. Appendix B contains a list of 28 chemicals found in various media at this site that lack sufficient toxicological data to determine their public health significance.
To identify industrial facilities that could contribute to the contamination near the Munisport Landfill site, we searched the 1987, 1988, and 1989 EPA Toxic Chemical Release Inventory (TRI) data base. EPA developed TRI from the chemical release information (air, water, and soil) provided by certain industries. Two industrial facilities in the Munisport Landfill area (33181 zip code) reported releases. Only the Magnum Marine Corporation marina, 14100 Biscayne Boulevard, reported releases of site-related contaminants of concern. Magnum Marine Corporation reported non-point air releases of 2,600 pounds of styrene in 1988 and 12,000 pounds in 1989.
Four facilities within 0.5 mile of the site have requested reimbursement from the Florida DER for cleanup of leaking underground petroleum storage tanks. Dade County DERM reports ground water at three of these facilities is, or has been, contaminated with petroleum products: Dade County Water and Sewer Authority, 2575 N.E. 151st St.; Phillips 66, 14200 Biscayne Blvd.; and Florida International University, 3000 N.E. 145th St. No ground water contamination has been discovered at Rinker Materials, 2001 N.E. 146th St.
In this assessment, the contamination that exists on the site will be discussed first, separately from the contamination that occurs off the site. "On site" is defined as the area within the Munisport Landfill property boundary (Figure 3, Appendix A). This includes all land within the dike, whether or not it was used for the landfill. "On-site" also includes the small section of land between N.E. 135th St. and Biscayne Bay but excludes the State of Florida Mangrove Preserve. This definition of "on-site" is consistent with past site descriptions.
In the following subsections we discuss contamination by media: landfill leachate, soil, surface water, sediments, ground water, air, and biota. Summary tables for the contaminants of concern in each medium are located in Appendix C. These summary tables list the maximum concentrations found, frequency of detection, and background and comparison values.
A. On-site Contamination
We compiled data in this subsection from City of North Miami, Dade County Department of Environmental Resource Management (DERM), Florida Department of Environmental Regulation (DER), and Environmental Protection Agency (EPA) investigations.
On-Site Landfill Leachate
In 1980, EPA collected one grab sample from a leachate outbreak near the north end of the northwest lake (5). Because the leachate outbreaks were sporadic, EPA was unable to collect additional samples. Leachate is the liquid that has passed through landfill material and usually contains dissolved chemicals and suspended solids. EPA found elevated levels of some metals and volatile organic chemicals in the leachate. Of the metals, only the concentration of lead was above its comparison value (Table 1, Appendix C). EPA did not analyze the leachate for extractable chemicals, pesticides, or polychlorinated biphenyls (PCBs). Without additional samples, we do not know if this sample is representative of the landfill leachate.
On-Site Soil
In 1984, EPA collected two soil samples from the landfill along the north lake and inside the dike near the southeast lake (Figure 3, Appendix A) (6). In 1988, EPA collected 23 more on-site soil samples and 2 off-site background samples (7). Figures 5-7 (Appendix A) show the locations of these soil samples, and Table 2 (Appendix C) reports the contaminants of concern and their maximum concentrations. We considered soil samples BK-1 (Biscayne Blvd. near the drive-in theater) and BK-2 (Biscayne Blvd. at N.E. 151st St.) as representative of background soil quality.
Although volatile organic chemicals, such as benzene were not detected, a few on-site soil samples contained di(2-ethylhexyl)phthalate, dieldrin, pentachlorophenol, and PCBs. Lead was found in most (18 of 25) soil samples taken on the site. Lead concentrations ranged from "not detected" to 87 milligrams per kilogram (mg/kg). Although the on-site soil lead concentrations were less than the background samples (110 and 180 mg/kg), the background samples are not representative of Florida soils. The lead concentration of most Florida soils is less than 10 mg/kg (8). The two background samples were collected along Biscayne Boulevard, a heavily traveled road likely to have high soil lead levels from deposition of leaded automobile exhaust.
Because the number of soil/fill samples is limited, we cannot determine the extent of contamination in the landfill portion of the site. Cover soil sampling on the landfill portion of the site (10 cover soil samples from 170 acres; 1 sample every 17 acres) is inadequate to fully characterize the extent of contamination. The fill material has not been sampled. Additional chemicals may be discovered and the concentrations of chemicals previously detected in the cover soil may be higher. As stated in the 1988 EPA remedial investigation report, "...limited soil sampling was conducted at the Munisport Landfill Site. There was no attempt to thoroughly characterize the soils in the landfill..." This report goes on to explain that no samples were taken from the fill material itself, only the cover soil, 0-1 foot deep (7). Thorough soil/fill sampling is especially important because of reports of hazardous waste disposal at this site. Nearby residents report the landfill operated 24 hours per day with little supervision. In 1976 Dade County DERM discovered 12 drums of liquid chemicals on the site. Recently a truck driver reported delivering drums and buckets of waste solvents to this site from a nearby boat manufacturing facility. The lack of thorough soil/fill sampling on the landfill portion of this site is a significant data gap.
Fifty surface soil samples (0 to 3 inches deep) and sixty fill material samples (5 to 10 feet deep) from the landfill portion of this site will be necessary to fully characterize the extent of contamination. This is based on an average one sample for every three acres of landfill (170 acres/3 = 57; minus 10 surface samples already collected = 47). The surface soil samples (0 to 3 inches deep) are necessary to identify the contaminants to which humans may be exposed if the vegetation is removed. Fill material samples (5 to 10 feet deep) are necessary to identify the contaminants to which humans may be exposed if the landfill material is uncovered.
On-Site Surface Water
Between 1975 and 1982, Florida DER and Dade County DERM analyzed 36 water samples from the eight on-site lakes. They also analyzed water samples from inside the dike and the culverts (9). In 1984, EPA analyzed 12 water samples from the on-site lakes (6). In 1988, EPA again sampled the water from the on-site lakes. They also took four water samples from inside the dike and two at the culverts (7). Figures 8 and 9 (Appendix A) show the locations of these surface water samples, and Table 3 (Appendix C) reports the contaminants of concern and maximum concentrations. Analyses detected ammonia and coliform bacteria in most water samples, carbon disulfide and zinc in some, and other contaminants of concern in few or none. The bacteriological quality of the on-site lakes has not been tested since 1982. There is no on-site background surface water with which to compare these concentrations. For this public health assessment, these samples adequately characterize the on-site surface water quality. Up-to-date sampling is needed, however, to determine current bacterial contamination in the on-site lakes.
On-Site Sediments
In 1984, EPA analyzed 12 sediment samples from the on-site lakes (6). In 1988, EPA analyzed four additional sediment samples from these lakes and two from the culverts (7). Figures 8 and 9 (Appendix A) show the locations of these sediment samples and Table 4 (Appendix C) reports the contaminants of concern and maximum concentrations. Analyses detected ammonia, vanadium, and zinc in most sediment samples; lead and polychlorinated biphenyls (PCBs) were detected in only a few. Other contaminants of concern were not detected. There are no on-site background sediments with which to compare these concentrations. For this public health assessment, these samples adequately characterize on-site sediment quality.
On-Site Ground Water
From 1975 to 1980, Florida DER and Dade County DERM analyzed ground water from six on-site monitor wells (Figure 10, Appendix A) (9). In 1984, EPA analyzed ground water from these wells and one new well (5). In 1987, the City of North Miami and the Florida DER analyzed the ammonia concentrations in ground water from five new on-site monitor wells (Figure 11, Appendix A) (10). In 1988, EPA analyzed ground water from 17 new on-site monitor wells (Figure 12, Appendix A) (7). We compiled analytical results for the contaminants of concern in Table 5 (Appendix C). Analyses detected ammonia in most ground water samples; coliform bacteria, lead, vanadium, and zinc in some; and other contaminants of concern in few or none. For this public health assessment, these samples adequately characterize on-site ground water quality.
We used ground water analyses from monitor wells #TW-1 (near the Biscayne Blvd. site entrance) and #MW-11A+B (about 1,000 feet west of the Biscayne Blvd. site entrance) as representative of background ground water quality.
On-Site Air
On April 10 and 11, 1990, EPA collected eight on-site air samples using Summa canisters and carbon tubes (11). This sampling was in response to complaints from nearby residents of smoke from a fire at the landfill. A fire started in the landfill material early in March 1990 and diminished by early April. Samples were taken directly from smoking vents in the landfill and also downwind (west) of the fire (Figure 13, Appendix A). The results (Table 6, Appendix C) show high concentrations of benzene in the smoke from the fire. Concentrations of benzene in the downwind sample were 100 times lower. EPA did not analyze the air samples for metals, bacteria, particulates, or extractable chemicals. EPA did not sample the background air quality for comparison.
Since EPA was unable to take air samples at the peak of the fire, these results are not representative of maximum air contaminant concentrations.
B. Off-site Contamination
"Off site" is defined as the area outside the Munisport landfill property boundary (Figure 3, Appendix A). We compiled data in this subsection from City of North Miami, Dade County Department of Environmental Resource Management (DERM), Florida Department of Environmental Regulation (DER), and Environmental Protection Agency (EPA) investigations. These agencies collected ground water, surface water, sediment, and biota (fish and oysters) from the adjacent mangrove preserve, Biscayne Bay, and Oleta River.
Off-Site Surface Soil
No off-site soil samples have been collected. We do not believe off-site surface soil sampling is necessary since there have been no reports or evidence of off-site disposal. Also, there have been no reports or evidence of significant transport of site contaminants to off-site surface soils. Stormwater run-off from the site has been mostly through the mangrove preserve where EPA has collected sediment samples.
Off-Site Surface Water
Between 1975 and 1982, Florida DER and Dade County DERM analyzed surface water samples from an off-site canal (9). In 1988, EPA analyzed four water samples from outside the dike, five from the canal south of the site, three from Biscayne Bay near the site, eight from the Oleta River, and one from the lagoon east of the site (7). In 1989, EPA analyzed five water samples from the mangrove preserve southeast of the site (12). Figures 9 and 14 (Appendix A) show the locations of these surface water samples and Table 7 (Appendix C) reports the contaminants of concern and maximum concentrations. Although impacted by nearby discharges, we used surface water samples #OR-6 (Oleta River north of North Miami Beach Boulevard), DC-1 (Dania Creek culvert), BP-1 (Black Point Creek), and BC (Biscayne Creek) as representative of off-site background surface water quality.
Analyses detected vanadium and coliform bacteria in most surface water samples, ammonia and carbon disulfide in some, and other contaminants of concern in few or none. The concentration of vanadium in the background sample was slightly greater than the maximum concentration in any other off-site samples. For this public health assessment, these samples adequately characterize off-site surface water quality.
Off-Site Sediments
In 1984, EPA analyzed one sediment grab sample from the mangrove preserve southeast of the site (6). In 1988, EPA analyzed four sediment grab samples from the mangrove preserve and five from the Oleta River (7). In 1989, EPA analyzed six additional sediment grab samples from the mangrove preserve (9). Figures 9 and 14 (Appendix A) show the locations of these samples, and Table 8 (Appendix C) reports the contaminants of concern and maximum concentrations. Analyses detected ammonia, vanadium, and zinc in most samples; lead in some; and other contaminants of concern in few or none. For this public health assessment, these samples adequately characterize off-site sediment quality.
We used sediment sample #OR-6 (Oleta River north of North Miami Beach Boulevard) and the six regional sediment samples from the 1989 EPA Water Quality and Toxic Assessment Study (12) as representative of background sediment quality.
Off-Site Ground Water
From 1975 to 1980, Florida DER and Dade County DERM analyzed ground water from six off-site monitor wells (9). In 1984, EPA analyzed ground water from three new wells (6). In 1988, EPA analyzed ground water from 10 new off-site monitor wells (7). Figures 10 and 12 (Appendix A) show the locations of these wells. We compiled analytical results for the contaminants of concern in Table 9 (Appendix C). Analyses detected ammonia in all ground water samples, lead and zinc in some, and other contaminants of concern in few or none. For this public health assessment, these samples adequately characterize off-site ground water quality.
We used ground water analyses from monitor wells #TW-1 (near the Biscayne Blvd. site entrance) and #MW-11A+B (about 1,000 feet west of the Biscayne Blvd. site entrance) as representative of background ground water quality.
Off-Site Biota
In 1987 the U.S. Fish and Wildlife Service collected eight fish and oyster samples from the State mangrove preserve and Biscayne Bay near the site. For comparison, they also collected six fish and oyster samples from areas of Biscayne Bay distant from the site. EPA analyzed these samples for metals, pesticides, and polychlorinated biphenyls (PCBs) (7). Figures 15-18 (Appendix A) show the sampling locations and Table 10 (Appendix C) summarizes the maximum concentrations of the contaminants of concern. Analyses identified zinc and PCBs in both fish and oysters near the site and at background locations away from the site. From the pattern of fish and oyster contamination, it does not appear that this site is the source of PCBs in Biscayne Bay. Additional samples are necessary to determine the extent of PCB contamination of fish, oyster, and other aquatic life in Biscayne Bay and the resulting threat to public health.
Off-Site Air
There are no air quality data for Highland Village mobile home park or other neighborhoods near the site. There are no air quality data on dust when the landfill was in operation. Since on-site air monitoring occurred after the 1990 landfill fire had subsided, we cannot determine the maximum off-site air concentrations. The site is now heavily vegetated, and off-site migration of contaminated dust is unlikely. Any future remediation, construction, or development that removes vegetation or uncovers the landfill material, however, may generate contaminated dust.
C. Quality Assurance and Quality Control
EPA confirmed that their analytical data underwent a formal quality assurance and quality control validation. We could not review this data review summary since it has already been archived. We assumed that estimated data (J) and presumptive data (N) were valid. This assumption errs on the side of public health by assuming that a contaminant exists when actually it may not exist. Florida DER and Dade County DERM did not perform formal data reviews on the samples they collected. We assume these data are valid, however, since environmental samples were collected and analyzed by state agencies or their contractors.
In preparing this public health assessment, we relied on the information provided by these agencies 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 are determined by the completeness and reliability of the referenced information.
D. Physical and Other Hazards
A 30-foot high mound of soil exists in the middle of the landfill. Although it is covered with vegetation, a 10-foot cliff where the soil has eroded could be a physical hazard to children who play on it. Dense undergrowth along the southwest site boundary next to the Highlands Village mobile home park harbors snakes, scorpions, and spiders that may threaten the health of these residents. These animals are not related to site contamination but are native to this area and thrive in the dense undergrowth.
As described in the previous section, prior to 1982 Florida DER and Dade County DERM found high levels of coliform bacteria in the on-site lakes. Children swimming in these lakes were at risk of infections such as hepatitis, meningitis, and gastroenteritis. The bacteriological quality of these lakes, however, has not been tested since 1982.
PATHWAYS ANALYSES
To determine whether nearby residents are exposed to contaminants migrating from the site, we evaluate 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.
We categorize exposure pathways 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: exposure could have occurred, could be occurring, or could occur in the future. An exposure pathway is eliminated if at least one of the five elements is missing and will never be present.
Table 11 (Appendix C) identifies the completed exposure pathways and Table 12 (Appendix C) identifies the potential exposure pathways. Only those pathways that are important and relevant to this site are discussed in detail.
A. Completed Exposure Pathways
Soil Pathway
Contaminated landfill soil/fill is a source, medium, and point of exposure for past, present, and future exposures (Table 11, Appendix C). There is ample evidence to support residents' assertions that children play and ride bicycles/motorbikes on the site. These children (number unknown) are the receptor population exposed to contaminated surface soil via skin contact and incidental ingestion.
Surface Water Pathway
Contaminated surface water in the on-site lakes is a medium and point of exposure for past, current, and future exposures (Table 11, Appendix C). Surface water contamination most likely originated in the landfill contents and leached into the adjacent lakes. Residents report that children (number unknown) swim in these lakes. Exposure occurs during swimming via skin absorption and incidental ingestion of the water.
Fish and Oyster Pathway
Ingestion of fish and oysters from Biscayne Bay is a past, current, and future exposure pathway (Table 11, Appendix C). The concentrations of PCBs in the fish and oysters collected near the site were similar to the concentrations collected from other distant areas of Biscayne Bay. This pattern suggests this site is not the source of PCBs in Biscayne Bay. Given its close proximity to a large urban area, there are many possible sources of the polychlorinated biphenyls (PCBs) found in the fish and oysters of Biscayne Bay. PCBs are adsorbed to particulate matter and carried from upland areas to the bay suspended in surface water or stormwater run-off. Fish and oysters then accumulate PCBs from particulates in the water. People who eat these contaminated fish and oysters are exposed via ingestion. Sport and subsistence fishing occurs in Biscayne Bay. Although, Biscayne Bay is closed to commercial oyster harvesting, the Dade County Public Health Unit reports unregulated private oyster harvesting and consumption. The number of people who eat fish and oysters from Biscayne Bay is unknown.
Air Pathway
Inhalation of contaminated dust is a past and future air exposure pathway (Table 11, Appendix C). Contaminated soils and fill material are sources of contaminated dust. Contaminated dust, generated by heavy machinery during landfill operations and by dirt bikes after the landfill closed, may have been carried by winds to the Highlands Village mobile home park. Approximately 1,500 residents of Highland Village mobile home park may have been exposed by inhalation. We cannot evaluate this pathway, however, since airborne dust was not tested. Currently, generation of dust from the landfill is unlikely due to the heavy vegetative cover. Future exposure is possible if the vegetation is cleared and the site is remediated or developed.
Inhalation of contaminated smoke is a past and future air exposure pathway (Table 11, Appendix C). The landfill material that caught fire in 1990 was the source of airborne contamination. The residents of Highland Village mobile home park (approximately 1,500) reported inhalation exposure to heavy black smoke. We cannot fully evaluate this pathway, however, since EPA was unable to mobilize an air sampling team in time to collect air samples before the fire subsided. Future exposure is possible if the landfill burns again.
B. Potential Exposure Pathways
Stormwater Run-off Pathway
Skin contact with contaminated stormwater run-off is a potential past and future exposure pathway for approximately 500 (one-third of the total) residents of Highland Village (Table 12, Appendix C). Occasionally, heavy rains cause the southeast landfill lake to overflow and flood the eastern third of Highland Village. On average, these rains may occur once every 2-3 years and leave standing water for 2 to 3 days. We can only classify this exposure as potential since the stormwater run-off has not been sampled.
Landfill Leachate Pathway
Skin contact with the leachate from the landfill was a potential past exposure pathway for an unknown number of site trespassers (Table 12, Appendix C). Before the landfill closed, EPA found leachate flowing from the landfill material into one of the on-site lakes. We can only classify this exposure as potential since we do not know if site trespassers came in contact with this leachate.
Soil Pathway
Incidental ingestion and skin contact with contaminated soil is a potential pathway for future site workers (Table 12, Appendix C). Contaminated soil would be the source, medium, and point of exposure. Incidental ingestion and skin contact would be the routes of exposure and remedial workers would be the exposed population. This is a potential pathway, however, since exposure may or may not occur.
Soil Gas Pathway
Inhalation of gases from the landfill is a future potential pathway for residents of Highland Village mobile home park (Table 12, Appendix C). If significant areas of the landfill adjacent to the Highland Village mobile home park are paved, landfill gases that currently migrate upward and dissipate may migrate latterly into Highland Village. Landfill material would be the source, air the medium, and houses in Highland Village the point of exposure. Inhalation would be the route of exposure and the residents of Highland Village the potentially exposed population. We categorize this pathway as future potential since exposure may or may not occur in the future.
C. Eliminated Pathways
Past, present, or future human exposure to the contaminated ground water at this site is unlikely. In Dade County, ground water near Biscayne Bay is not potable due to saltwater intrusion. Before Munisport began landfill operations in 1974, drinking water and irrigation wells near the Bay were abandoned due to saltwater intrusion. Although there have been reports of private well use in this area as late as 1985, most homes and businesses are supplied with municipal water from wells further inland. Currently there are no plans to use ground water in this area. It is unlikely that contamination from this site will migrate inland since regional ground water flow is toward Biscayne Bay. Since human exposure to the contaminated ground water is unlikely, we will not discuss it in the remainder of this assessment.
Past, present, or future human exposure to the contaminated sediments is also unlikely since they remain covered with water and unavailable for skin absorption or incidental ingestion.
PUBLIC HEALTH IMPLICATIONS
In this section we discuss the health effects on persons exposed to specific contaminants, evaluate state health databases, and address specific community health concerns.
A. Toxicological Evaluation
Introduction
To evaluate health effects, ATSDR develops Minimal Risk Levels (MRLs) for contaminants commonly found at hazardous waste sites. An MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. ATSDR develops MRLs for each route of exposure: skin absorption, ingestion, and inhalation; and for various lengths of exposure: acute (less than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). ATSDR presents these MRLs in chemical-specific toxicological profiles. These profiles provide information on health effects, environmental transport, human exposure, and regulatory status. In the following discussion, we use the ATSDR toxicological profiles for ammonia, benzene, di(2-ethylhexyl)phthalate, cadmium, carbon disulfide, chloromethane, lead, methylene chloride, pentachlorophenol, PCBs, styrene, vanadium, and zinc. When ATSDR MRLs are unavailable, we use the EPA Reference Dose (RfD). RfDs are estimates of daily human exposure that are unlikely to cause adverse health effects over a lifetime of exposure.
In this section, we use the following standard assumptions to estimate human exposure from incidental ingestion of contaminated soil, incidental ingestion of contaminated water (during swimming), and ingestion of contaminated fish and oysters.
To estimate exposure from incidental ingestion of contaminated soil, we assume: 1) children between the ages of 1 and 6 ingest an average of 200 milligrams (mg) of soil per day, 2) these children weigh about 10 kilograms (kg), and 3) they ingested soil on the landfill at the maximum concentration measured for each contaminant.
To estimate exposure from incidental ingestion of contaminated surface water during swimming in the on-site lakes, we assume: 1) children between the ages of 6 and 18 swim in the on-site lakes, 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 kilograms (kg), and 6) they were exposed to the maximum concentration measured for each contaminant.
To estimate exposure from ingestion of contaminated fish and oysters, we assume: 1) recreational fishermen eat about 66 grams (g) of fish and oysters from Biscayne Bay per day, 2) these fishermen weigh about 70 kilograms (kg), and 3) they eat fish or oysters at the maximum concentration measured for each contaminant. The fish and oyster consumption rate of 66 g/day is based on an estimate by Pao et al. (13) of 132 grams per day (the 95th percentile daily intake averaged over three days for consumers of fin fish) multiplied by 50% (an estimate of the percentage of a individual's total fish consumption that comes from Biscayne Bay).
Ammonia
Trespassers on the site may have been exposed to ammonia via incidental ingestion of the soil. They may also have been exposed to ammonia via incidental ingestion of the surface water when swimming in the on-site lakes. These exposures, however, are unlikely to cause adverse health effects.
The estimated daily dose of ammonia from incidental ingestion of contaminated soil is less than the ATSDR intermediate Minimal Risk Level (MRL) (14). A chronic MRL is not available for comparison. Ammonia has not been identified as causing cancer. Therefore, for exposures of less than a year, incidental ingestion of ammonia contaminated soil at this site is unlikely to cause adverse health effects. Adverse health effects from exposure to ammonia from these soils via skin absorption is also unlikely since skin absorption is insignificant compared to ingestion.
The estimated daily dose of ammonia from incidental ingestion of contaminated water (during swimming) is less than the ATSDR intermediate Minimal Risk Level (MRL) (14). A chronic MRL is not available for comparison. Ammonia has not been identified as causing cancer. Therefore, for exposures of less than a year, incidental ingestion of ammonia contaminated surface water when swimming in the on-site lakes is unlikely to cause adverse health effects. Adverse health effects from exposure to ammonia from this water via skin absorption are also unlikely since skin absorption is insignificant compared to ingestion.
Even though children 1 to 6 years old are unlikely to swim in these lakes and children 6 to 18 years old are less likely to ingest soil, a combination of the estimated doses for both of the above routes of exposure would not exceed the MRL. That is, children exposed to ammonia at this site by both incidental ingestion of contaminated soil and ingestion of contaminated water during swimming, are unlikely to suffer ill health effects.
Although EPA did not analyze any biota samples for ammonia, ammonia does not bioaccumulate in fish and oysters. EPA did not analyze the air samples for ammonia. Although EPA did not analyze the landfill leachate sample for ammonia and has not analyzed any stormwater samples, we consider skin absorption from these two sources insignificant.
Benzene
Although EPA measured benzene in the smoke coming from the landfill, we cannot evaluate the public health threat for two reasons. First, EPA was unable to mobilize an air sampling team before the fire subsided. The benzene concentrations at the peak of the fire may have been higher. Second, EPA collected the air samples at the landfill, not in the nearby residential neighborhoods where human exposure occurred. We do not know how much the benzene in the smoke was diluted before it reached these residents. In 1990 and 1991 memos, ATSDR concluded that the measured benzene concentrations were unlikely to have caused health effects in nearby residents. ATSDR failed, however, to address the fact that these measurements were taken weeks after the fire subsided.
The maximum benzene concentration measured in the smoke directly from the landfill exceeds the draft ATSDR acute Minimal Risk Level (15). Short-term (1-14 days) inhalation of benzene at this concentration could result in damage to the immune system. Long-term (> 1 year) inhalation of benzene at this concentration could result in a "moderate" increased risk of cancer. Although EPA did not detect benzene in the downwind air samples, we do not know the maximum residential benzene concentrations and therefore cannot evaluate the public health threat.
Benzene was not detected in the landfill leachate sample or any soil or surface water samples. Although EPA did not analyze any biota samples for benzene, benzene does not bioaccumulate in fish and oysters. Although stormwater run-off has not been sampled, it is unlikely to contain benzene since it was not detected in any surface water samples.
Cadmium
Trespassers on the site may have been exposed to cadmium via incidental ingestion of contaminated surface water when swimming in the on-site lakes. This exposure, however, is unlikely to cause adverse health effects.
The estimated daily dose of cadmium from incidental ingestion of water (during swimming) is less than the draft ATSDR chronic Minimal Risk Level (MRL) (16). Thus, incidental ingestion of surface water when swimming in the on-site lakes is unlikely to cause adverse health effects. Adverse health effects from exposure to cadmium in this water via skin absorption are also unlikely since skin absorption is insignificant compared to ingestion.
EPA did not detect cadmium in the surface soil, the landfill leachate sample, or the fish and oysters tested. EPA did not test the air samples for cadmium.
Carbon Disulfide
Trespassers on the site may have been exposed to carbon disulfide via incidental ingestion of contaminated surface water when swimming in the on-site lakes. This exposure, however, is unlikely to cause adverse health effects.
The estimated daily dose of carbon disulfide from incidental ingestion (during swimming) is less than the EPA Reference Dose (RfD) (17). Skin absorption of carbon disulfide is likely but the rate is unknown. Carbon disulfide has not been identified as causing cancer. Therefore, incidental ingestion of carbon disulfide contaminated surface water when swimming in the on-site lakes is unlikely to cause adverse health effects.
EPA did not detect carbon disulfide in the soil. The fish and oysters were not tested for carbon disulfide but carbon disulfide is not known to bioaccumulate. EPA did not test the landfill leachate sample or the air samples for carbon disulfide.
Chloromethane
Trespassers on the site may have been exposed to chloromethane via incidental ingestion of contaminated surface water when swimming in the on-site lakes. This exposure, however, is unlikely to cause adverse health effects.
Although there is no evidence of chloromethane causing cancer in humans, EPA has classified chloromethane as a possible human carcinogen based on limited evidence in animal testing. The concentrations at this site are so low, however, that the risk of cancer from incidental ingestion of the surface water is insignificant. Skin absorption of chloromethane is likely but the rate is unknown. Therefore, incidental ingestion of chloromethane contaminated surface water when swimming in the on-site lakes is unlikely to cause adverse health effects.
EPA detected chloromethane in one air sample but the concentration was below the ATSDR chronic inhalation Minimal Risk Level (MRL) and is unlikely to cause any adverse health effect (18). EPA did not detect chloromethane in the soil. The fish and oysters were not tested for chloromethane but chloromethane is not known to bioaccumulate. EPA did not test the landfill leachate sample for chloromethane.
Coliform Bacteria
In the past, children and other trespassers on the site may have been exposed to coliform bacteria via incidental ingestion of contaminated water when swimming in the on-site lakes. This exposure may have caused adverse health effects. We can not determine the current health threat from swimming in these lakes because they have not been tested for coliform bacteria since 1982.
There are no standards to compare an estimate of the dose of coliform bacteria that children swimming in the on-site lakes may have been exposed to. The maximum concentration of total coliform bacteria measured by Florida DER and Dade County DERM in the on-site lakes prior to 1982, however, was 5,400 times the state drinking water standard and 5.4 times the state surface water standard (19). Although not considered Superfund hazardous waste, coliform bacteria are indicators of fecal contamination. Florida DER and Dade County DERM also measured elevated concentrations of fecal coliform and fecal streptococcus bacteria in these lakes. Thus children swimming in the on-site lakes may have been exposed to disease causing bacteria or viruses. As a result of this exposure, these children were at a higher risk of infections such as hepatitis, meningitis, and gastroenteritis.
Dieldrin
Trespassers on the site may have been exposed to dieldrin via incidental ingestion of the contaminated soil. People eating fish and oysters from Biscayne Bay may also have been exposed to dieldrin. The combined exposure to soil, fish, and oyster, however, are unlikely to cause adverse health effects.
The estimated daily doses of dieldrin from ingestion of contaminated fish and oysters and incidental ingestion of contaminated soil are less than the EPA oral Reference Dose (RfD) (20). Although there is no evidence of dieldrin causing cancer in humans, EPA has classified dieldrin as a probable human carcinogen based on limited evidence in animal testing. The fish, oyster, and soil concentrations are so low, however, that the risk of cancer is insignificant. Therefore, incidental ingestion of dieldrin contaminated soil and ingestion of dieldrin contaminated fish and oysters and at this site is unlikely to cause adverse health effects. Adverse health effects from exposure to dieldrin from these soils via skin absorption is also unlikely since skin absorption is insignificant compared to ingestion.
EPA did not detect dieldrin in any surface water samples.
Di(2-ethylhexyl)phthalate
Trespassers on the site may have been exposed to di(2-ethylhexyl)phthalate via incidental ingestion of the contaminated soil. The maximum soil concentrations, however, are unlikely to cause adverse health effects.
The estimated daily dose of di(2-ethylhexyl)phthalate from incidental ingestion is less than the estimated chronic Minimal Risk Level (MRL) (21). Di(2-ethylhexyl)phthalate has been identified as causing cancer in laboratory animals. The soil concentrations are so low, however, that the risk of cancer from incidental ingestion is insignificant. Therefore, incidental ingestion of di(2-ethylhexyl)phthalate contaminated soil at this site is unlikely to cause adverse health effects. Adverse health effects from exposure to di(2-ethylhexyl)phthalate from these soils via skin absorption is also unlikely since skin absorption is insignificant compared to ingestion.
EPA did not detect di(2-ethylhexyl)phthalate in any surface water samples. EPA did not analyze the landfill leachate sample, the air samples, or the fish and oyster samples for di(2-ethylhexyl)phthalate.
Lead
Trespassers on the site may have been exposed to lead via incidental ingestion of contaminated surface soil and incidental ingestion of contaminated surface water when swimming in the on-site lakes. Although ATSDR and EPA have no lead exposure guidelines (MRLs or RfDs) for comparison (22), we estimate the combined exposure to on-site soil and surface water are unlikely to cause adverse health effects. EPA did not detect lead in the fish or oysters.
The Centers for Disease Control of the U.S. Public Health Service estimates that blood lead levels generally rise 3-7 micrograms per deciliter (µg/dL) for every 1,000 milligram per kilogram (mg/kg) increase in soil lead concentration (23). Thus the maximum soil lead concentration on the site, 87 mg/kg, is unlikely to increase the blood lead level of children trespassing on this site past the 10 µg/dL definition of lead poisoning. Although the maximum concentration of lead in the on-site lakes (0.063 mg/L) is four times greater than the Florida drinking water standard (0.015 mg/L), we estimate the annual volume of water ingested during swimming in these lakes is 100 times less that the annual volume of water ingested from drinking water sources. Therefore, we estimate the dose of lead from incidental ingestion during swimming in these lakes is about 25 times less than the dose from drinking water at the Florida standard.
Methylene Chloride
Although EPA measured methylene chloride in the smoke coming from the landfill, we cannot evaluate the public health threat for two reasons. First, EPA was unable to mobilize an air sampling team until the fire subsided. The methylene chloride concentrations at the peak of the fire may have been higher. Second, EPA collected the air samples at the landfill, not in the nearby residential neighborhoods where human exposure occurred. We do not know how much the methylene chloride in the smoke was diluted before it reached these residents. In 1990 and 1991 memos, ATSDR concluded that the measured methylene chloride concentrations were unlikely to have caused health effects in nearby residents. ATSDR failed, however, to address the fact that these measurements were taken weeks after the fire subsided.
The concentration of methylene chloride measured in the smoke directly from the landfill fire is less than the draft ATSDR acute and intermediate Minimal Risk Levels (MRLs) (24). A chronic MRL is unavailable. Although there is no evidence of methylene chloride causing cancer in humans, EPA has classified it as a probable human carcinogen based on limited evidence in animal testing. The risk of cancer from exposure to the maximum methylene chloride concentration measured, however, is insignificant.
EPA did not detect methylene chloride in the landfill leachate sample nor in any soil or surface water samples. Although EPA did not analyze any biota samples for methylene chloride, it does not bioaccumulate in fish and oysters.
Pentachlorophenol
Trespassers on the site may have been exposed to pentachlorophenol via incidental ingestion of the contaminated soil. The maximum soil concentrations, however, are unlikely to cause adverse health effects.
The estimated daily dose of pentachlorophenol from ingestion of contaminated soil is less than the intermediate ATSDR Minimal Risk Level (MRL) (25). A chronic MRL is not available. Although there is no evidence of pentachlorophenol causing cancer in humans, EPA has classified pentachlorophenol as a possible human carcinogen based on limited evidence in animal tests. The soil concentrations are so low, however, that the risk of cancer from incidental ingestion is insignificant. Therefore, incidental ingestion of pentachlorophenol contaminated soil at this site is unlikely to cause adverse health effects. Adverse health effects from exposure to pentachlorophenol from these soils via skin absorption is also unlikely since skin absorption is insignificant compared to ingestion.
EPA did not detect pentachlorophenol in any surface water samples. EPA did not analyze the landfill leachate sample, the air samples, or the fish and oyster samples for pentachlorophenol.
Polychlorinated Biphenyls (PCBs)
People eating fish and oysters from Biscayne Bay may have been exposed to polychlorinated biphenyls (PCBs). Long-term ingestion of fish and oysters at the maximum PCB concentration found may affect the immune system and result in a "low" increased risk of cancer. The pattern of fish and oyster contamination, however, suggest that this site is not the source of PCBs in Biscayne Bay. Trespassers on the site may have also been exposed to PCBs via incidental ingestion of the contaminated soil. The maximum soil concentrations, however, are unlikely to cause adverse health effects.
The estimated daily dose of PCBs from eating contaminated fish and oysters from Biscayne Bay exceeds the draft ATSDR chronic MRL (26). In contrast, the maximum fish and oyster PCB concentrations are less than the U.S. Food and Drug Administration (FDA) tolerance level of 2 mg/kg for fish and shellfish (27). FDA tolerance levels are maximum allowable levels of poisonous substances in human food and animal feed. Based on the ATSDR chronic MRL, we conclude that lifetime consumption of fish and oysters from Biscayne Bay at the maximum PCB concentrations would result in a "low" increased risk of cancer.
The estimated daily dose of PCBs from incidental ingestion of contaminated soil is less than the draft ATSDR chronic Minimal Risk Level (MRL) (26). Although there is no evidence of PCBs causing cancer in humans, EPA has classified PCBs as probable human carcinogens based on limited evidence in animal tests. The soil concentrations are so low, however, that the risk of cancer from incidental ingestion is insignificant. Therefore, incidental ingestion of PCB contaminated soil at this site is unlikely to cause adverse health effects. Adverse health effects from exposure to PCBs in these soils via skin absorption is also unlikely since skin absorption is insignificant compared to ingestion.
EPA did not detect PCBs in any surface water samples. EPA did not analyze the landfill leachate sample or the air samples for PCBs.
Styrene
Although EPA measured styrene in the smoke coming from the landfill, we cannot evaluate the public health threat for two reasons. First, EPA was unable to mobilize an air sampling team until the fire subsided. The styrene concentrations at the peak of the fire may have been higher. Second, EPA collected the air samples at the landfill, not in the nearby residential neighborhoods where human exposure occurred. We do not know how much styrene in the smoke was diluted before it reached these residents. In 1990 and 1991 memos, ATSDR concluded that the measured styrene concentrations were unlikely to have caused health effects in nearby residents. ATSDR failed, however, to address the fact that these measurements were taken weeks after the fire subsided.
The maximum styrene concentrations measured in the undiluted smoke directly from the landfill exceeds the draft ATSDR chronic Minimal Risk Level (28). Long-term inhalation (> 1 year) of styrene at this concentration could result in damage to the blood system and a "moderate" increased risk of cancer. Although EPA did not detect styrene in the downwind air samples, we do not know the maximum residential styrene concentrations and therefore cannot evaluate the public health threat.
Styrene was not detected in any soil or surface water samples. Although EPA did not analyze any biota samples for styrene, it does not bioaccumulate in fish and oysters. EPA did not analyze the landfill leachate sample for styrene.
Vanadium
Trespassers on the site may have been exposed to vanadium via incidental ingestion of contaminated water when swimming in the on-site lakes. People eating fish and oysters from Biscayne Bay may also have been exposed to vanadium. The combined exposures from the surface water and fish and oyster, however, 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 Minimal Risk Level (MRL) (29). A chronic MRL is unavailable. Vanadium has not been identified as causing cancer. Therefore, incidental ingestion of vanadium contaminated surface water when swimming in the on-site lakes is unlikely to cause adverse health effects. Adverse health effects from exposure to vanadium via skin absorption is also unlikely since vanadium is not well absorbed across the skin.
The estimated maximum dose of vanadium from ingestion of contaminated fish and oysters is less than the draft ATSDR intermediate Minimal Risk Level (MRL) (28). A chronic MRL is unavailable. There is no evidence of vanadium causing cancer. Therefore, the maximum vanadium concentration in fish or oysters tested is unlikely to cause any adverse health effects.
EPA did not detect vanadium in the surface soil or the landfill leachate samples. EPA did not test the air samples for vanadium.
Zinc
Trespassers on the site may have been exposed to zinc via incidental ingestion of the contaminated soil and incidental ingestion of contaminated water when swimming in the on-site lakes. People eating fish and oysters from Biscayne Bay may also have been exposed to zinc. The combined exposures from soil, surface water, and fish and oyster, however, are unlikely to cause adverse health effects.
The estimated daily dose of zinc from incidental ingestion of contaminated soils is less than the estimated ATSDR chronic Minimal Risk Level (MRL) (30). Zinc has not been shown to cause cancer. Therefore, incidental ingestion of zinc contaminated soil at this site is unlikely to cause adverse health effects. Adverse health effects from exposure to zinc in these soils via skin absorption is also unlikely since zinc is not well absorbed across the skin.
The estimated daily dose of zinc from incidental ingestion of water (during swimming) is less than the estimated ATSDR chronic Minimal Risk Level (MRL) (30). Zinc has not been identified as causing cancer. Therefore, incidental ingestion of zinc contaminated water when swimming in the on-site lakes is unlikely to cause adverse health effects. Adverse health effects from exposure to zinc from this water via skin absorption is also unlikely since zinc is not well absorbed across the skin.
The estimated daily dose of zinc from eating contaminated fish and oysters is less than the estimated ATSDR chronic Minimal Risk Level (MRL) (30). There is no evidence of zinc causing cancer. Therefore, the maximum zinc concentration in fish or oysters tested is unlikely to cause any adverse health effects.
We believe it is unlikely that skin contact with the landfill leachate resulted in significant exposure to zinc since zinc is not well absorbed. EPA did not test the air samples for zinc.
B. Health Outcome Data Evaluation
Guided by community concerns of increased cancer incidence in the population living near the site, Florida HRS epidemiologists reviewed the Florida Cancer Data System (FCDS). See the Background, Health Outcome Data section of this report for a description of the FCDS. Florida HRS epidemiologists found no significant excess of all cancers in the 33181 zip code, which includes the site and surrounding neighborhoods. There are, however, limitations with FCDS and environmental epidemiology investigations.
2. In environmental epidemiology, exposure assessment is difficult. As with most Superfund sites, we do not have direct measures of exposure at this site. We do not know to which chemicals, to how much of each chemical, and for how long people were actually exposed. In our analysis of the cancer rates, we used the distance from the place of residence to site as an estimate of exposure. Although distance from the place of residence to the site is a poor estimate of exposure, at this site, it is the best estimate we have.
3. The high background incidence of cancer makes small increases hard to detect. The background frequency of cancer in the United States is approximately 25%. Increase in the cancer rate near this site would have to be significant to be detected.
In general, failure to establish a link between the site and the health of nearby residents may be more indicative of the limitations of the existing data and epidemiological methods than the lack of an effect. Based on the available data and epidemiological methods, we can not determine if the Munisport Landfill has caused an increase in the incidence of cancer among residents of the Highland Village mobile home park.
C. Community Health Concerns Evaluation
We address community health concern as follows:
Air Exposure Health Concerns
1. Highland Village residents are concerned that until the landfill closed and heavy vegetation covered the site, they were exposed to contaminated dust including asbestos. They are concerned that rashes, respiratory illnesses, and infections they suffered in the 1970's and 1980's were caused by exposure to this dust. They are concerned that they will suffer health effects from exposure to contaminated dust resulting from future remediation and/or construction on the landfill.
2. Highland Village residents are concerned that toxic smoke from the March/April 1990 landfill fire aggravated existing respiratory conditions and may result in other long-term health effects. They are concerned that the April 10-11, 1990 EPA air monitoring was too late to measure the maximum concentrations of toxic chemicals generated by this fire.
We cannot evaluate the public health threat from inhalation of toxic chemicals from this fire since we do not know the maximum concentrations nearby residents were exposed to. We cannot estimate maximum residential exposure concentrations from air samples taken at the landfill after the fire had subsided. Chemical concentrations at the landfill during the peak intensity of the fire may have been higher. Chemical concentrations at nearby residences, however, may have been lower due to dilution. Without peak residential measurements, we cannot estimate exposure or predict health effects.
3. Highland Village residents are concerned that they may suffer adverse health effects from continuous exposure to gases such as methane, benzene, and styrene emitted from the landfill. They are concerned because the ambient air quality of their neighborhood has not been monitored.
Skin Exposure Health Concerns
4. Highland Village residents are concerned that they may suffer health effects from skin contact with contaminated stormwater that runs off the landfill and floods their neighborhood. They are concerned that the proposed remediation will increase the frequency of flooding of their neighborhood.
EPA, Florida DER, and the City of North Miami plan to further characterize the local hydrology and develop a plan to control stormwater runoff and flooding in Highland Village.
5. Highland Village residents are concerned that their children swam in the on-site lakes and may suffer health effects from exposure to toxic chemicals.
6. Highland Village residents are concerned that their children have suffered increased rates of eye irritation and infection from swimming at the Oleta State Recreation Area and in the lagoon adjacent to Florida International University.
7. The manager of a youth facility northeast of the site is concerned that their children developed serious skin infections after being cut or scratched.
Other Health Concerns
8. Highland Village residents are concerned that they may have been exposed to radiation from radioactive hospital waste disposed of in the landfill.
9. Highland Village residents are concerned that their children and other trespassers on the landfill may have suffered higher rates of infection from exposure to hospital waste.
10. Highland Village residents are concerned that they may suffer health effects from contact with snakes, scorpions, and spiders that live in the dense undergrowth along the southern landfill boundary.
11. Highland Village residents are concerned that people who eat landcrabs from the tidal areas near the landfill may be exposed to toxic chemicals.
12. Highland Village residents are concerned that there have been an inordinately high number of cancers in their neighborhood during the past 10 years. They are concerned these cancers are caused by exposure to toxic chemical from the landfill.
13. One Highland Village resident has experienced intermittent swelling of the face, hands, and feet. This resident is concerned the swelling is caused by exposure to site contaminants.
