PUBLIC HEALTH ASSESSMENT
PALM CITY, MARTIN COUNTY, FLORIDA
The Agency for Toxic Substances and Disease Registry (ATSDR) was petitioned in 1996 for a public health assessment of the Loxahatchee Nursery site in Palm City, Florida. The main health concern of the community is contamination of private wells by pesticides leaching into the groundwater from the nursery site. Other concerns include the potential contamination of residential soils; the potential contamination of surface waters flowing from the site through drainage ditches; the potential contamination of the site and surrounding area by the chemicals, benlate and flusilazole; the incidence of cancer in the residential community surrounding the nursery site; the dangers to children playing on the site near the ponds and buildings; and the future development of the site for residential housing.
The Loxahatchee Nursery site began operating as a flower farm in the 1940's. In 1972, the flower farm converted to a nursery and began to grow specialty and long-term growth plants. Throughout the nursery's history, normal operations at the site included the use of pesticides. In January 1992, the nursery site ceased operations and was cleared of all plants in an agreement between the operators and Dupont (ATSDR, 1996a). Environmental sampling of monitoring wells, private wells, soils, and sediments was conducted.
The Loxahatchee Nursery site is not currently fenced. One pond is located on site. During ATSDR's site visit, the staff noted that the remaining structures on site were in a state of disrepair. ATSDR concludes that the on-site pond and dilapidated structures could pose a potential physical hazard to area residents, especially children, who trespass on site.
Based on a review of available environmental and toxicologic data, ATSDR determined that the Loxahatchee Nursery site in Palm City, Florida poses no apparent public health hazard from chemical contamination. ATSDR identified a completed exposure pathway to groundwater through the use of private wells in the area; however, the contaminants in drinking water from private wells in the area surrounding the Loxahatchee Nursery site are not at levels of health concern. Potential exposures to soil and sediment, both on site and off site, have also been identified. ATSDR concludes that, under site-specific conditions of exposure, none of the contaminants detected in soil or sediment are likely to pose a hazard to public health. Given that only low levels of contaminants were detected in on-site soils and drainage ditch sediments, it is unlikely that the on-site pond contains elevated levels of contaminants. However, because no chemical-specific environmental sampling of the on-site pond has occurred, ATSDR has identified this as a data gap.
Based on the information reviewed for this public health assessment, ATSDR has made the following recommendations: (1) sample private well water on a periodic basis to ensure that residents will not be exposed in the future to constituents in groundwater at levels of health concern; (2) restrict access to the on-site pond and dilapidated structures as they could pose a physical hazard to individuals, especially children, who trespass on site; and (3) characterize on-site pond water and sediment to determine the presence or absence of contamination at levels of health concern.
The Loxahatchee Nursery site began operating as a flower farm in the 1940's. In 1972, the flower farm converted to a nursery and began to grow specialty and long-term growth plants. After the nursery site ceased operations in January 1992, the nursery was cleared of all plants in an agreement between the operators and Dupont (ATSDR, 1996a). An environmental audit in early 1992 discovered petroleum and chlorinated pesticide constituents in the soil and groundwater at the nursery site (HRS, 1996a).
Throughout the nursery's history, pesticides were routinely stored in the pesticide storage building and fertilizers were delivered to the plants through the nursery's irrigation system. In March 1992, after an abandoned underground storage tank was discovered and removed, low levels of pesticides were found in soil and groundwater samples collected near the tank (EPA, 1998a). In 1994, another storage tank was discovered at the site and its contents were removed (EPA, 1998a). From 1993 to 1998, several rounds of hydrocarbon and pesticide testing of private wells occurred. In July 1996, one private well contained concentrations of 1,2-dichloropropane as high as 150 parts per billion (ppb) which exceeds the United States Environmental Protection Agency's (EPA) maximum contaminant level (MCL) of 5 ppb. This well was fitted with a carbon filter in August 1996 which removes the contaminant from the water (EPA, 1998a). Methyl bromide, a nematocide, and benomyl (trade name Benlate), a Dupont fungicide, were reportedly used at the site.
EPA is currently investigating the site under the authority of the Superfund program to determine if any further action is necessary (EPA, 1998a). Groundwater, soil, and sediment samples were collected and tested for various chemicals including pesticides, metals, and organic compounds in March 1998 (EPA, 1998a). During the March 1998 EPA sampling event, the Florida Department of Environmental Protection (FDEP) was also on site and collected split samples at the same locations as the EPA.
Since ATSDR was petitioned in 1996, ATSDR site activities have included the development of a health consultation, a petition scoping report, and a draft public health assessment. In September 1996, ATSDR reviewed available data and information for the Loxahatchee Nursery site in a health consultation. This review was initiated to determine if adequate sampling had been conducted and to determine if additional environmental sampling was needed to define the extent of contamination at the site (ATSDR, 1996a). Based on the information provided to ATSDR, recommendations were made to further characterize several media. A copy of this health consultation is contained in Appendix F.
In October 1996, the ATSDR Petition Screening Committee determined that there was a reasonable basis for conducting additional public health activities at the nursery site. ATSDR forwarded the recommendations from the health consultation (which focused on the need for additional sampling data) to the EPA. The EPA and FDEP conducted sampling activities in March 1998. ATSDR released a draft of the public health assessment for public comment in July 1998. Appendix G contains the specific comments ATSDR received during the public comment period and the agency's response to those comments.
ATSDR staff visited the site in March 1998. ATSDR staff met with the petitioner and another concerned resident to provide an update of the Agency's efforts with relation to the nursery site. ATSDR staff met with the Martin County Health Department (MCHD) to gather additional information about current site activities. Lastly, ATSDR staff toured the site with the petitioner and representatives from the EPA and FDEP. During the tour, ATSDR staff identified areas of potential contamination and requested samples be collected in these areas.
ATSDR staff visited the site again in August 1998. During this site visit, ATSDR staff held public availability sessions and a public meeting to address health concerns the resident's expressed and answer any questions the residents had about the draft public health assessment. EPA, FDEP, and MCHD staff participated in the public availability sessions and the public meeting.
The 1990 Census of Population and Housing demographic statistics for locations within 1 mile of the site indicated that 4,201 persons reside in 2,583 households. Of the 4,201 persons, 98.7 % are white; 0.45 % are black; 0.071 % are American Indian, Eskimo, Aleut; 0.62 % are Asian or Pacific Islander; and 0.095 % are members of other ethnic groups. There are 281 children aged 6 or younger and 1,357 adults aged 65 and older (US Bureau of the Census, 1991). Please refer to Figure 2, Appendix B, for additional demographic statistics.
- Land use
The Loxahatchee Nursery site is located in Palm City, Martin County, Florida. The approximately 10-acre site is bounded by SW Mapp Road (to the south and west), SW Mockingbird Lane (to the north), and SW Mooring Drive (to the east). A residence is located on site. The area surrounding the nursery site contains residential homes and a county park. The Gull Harbor residential area is located to the east and the Pelican Cove residential area is located to the north of the nursery. The South Fork of the St. Lucie River is to the east of the nursery and Gull Harbor. Martin County Park is located directly west and south of the site, just across SW Mapp Road. The park contains ball fields and jogging/nature trails (ABB-ES, 1998). The future use of the site is intended to be residential.
- Natural Resource Use
The residents surrounding the Loxahatchee Nursery site receive their drinking water from private
wells. Most of the private wells range from 80 to 120 feet deep (ATSDR, 1998b). One pond is
located on the western section of the site. The site topography slopes to the east and surface
water runoff flows into the drainage canals that drain into Gull Harbor (ATSDR, 1996a). The
South Fork of the St. Lucie River, located to the east of the nursery, is not used as a drinking
water source; however, the river is used for recreation such as swimming, boating and fishing
(ATSDR, 1998b). Because the entire area is a wetland, low lying areas flood during heavy rains.
In this area, the water table is encountered at 8 feet, or less, below ground surface (ATSDR, 1998c). A septic system exists on site, but its location and use are not known (ATSDR, 1998a).
As part of the petition process, ATSDR staff have gathered health concerns from the local community. These concerns are summarized below and addressed in the Community Health Concerns Evaluation section of this public health assessment. These concerns include:
- contamination of private wells by pesticides leaching into the groundwater from the nursery site;
- contamination of residential soil and contamination of surface water flowing from the site through the drainage ditches within the community;
- contamination of the site and surrounding area by the chemicals, benlate and flusilazole;
- incidence of cancer in the residential community surrounding the nursery;
- dangers to children playing on the site near the ponds and buildings; and
- future development of the site for residential housing.