PUBLIC HEALTH ASSESSMENT
ST. THOMAS, U.S. VIRGIN ISLANDS
The Bovoni Landfill comprises approximately 34 acres on a southeast peninsula of St. Thomas, U.S. Virgin Islands. This active landfill has a history of accepting municipal, industrial, and medical wastes and debris from construction activities and hurricanes. An underground fire at the landfill emits combustion products through fissures in the landfill surface. The underground fire also breaks through the surface occasionally and covers the island with black smoke. In April 1996, a community group petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) to evaluate the public health impact of the Bovoni Landfill. The primary concern was the emission of potentially harmful fumes during above-ground fire events.
Based on a review of available data, ATSDR has concluded that the Bovoni Landfill site constitutes a public health hazard. Numerous physical hazards, such as fast- moving trucks, unstable earth, and potential fires and explosions exist as well as potentially harmful fumes emitted through open fissures and vents in the landfill surface. Because there were no off-site air data, it was not possible to assess the site's potential impact on public health in off-site areas properly. Because only limited environmental data are available, it is difficult to determine the levels of contaminants to which individuals may actually be exposed at the landfill. A completed exposure pathway for air has been identified for on-site workers and area residents. All completed exposures to air contaminants are likely to be intermittent and of intermediate duration, and their magnitude is expected to be greatest during surface fires. Potential exposure pathways have also been identified for groundwater, cistern water, and sediment.
On-site air monitoring indicated that, with the exception of phosgene from a smolder pit fissure and mercury vapor in the burn pit area, all contaminants were below levels of health concern. Even after dilution in ambient air, the concentration of phosgene emanating from the smolder pit fissures may have been high enough to have contributed to the respiratory complaints of on-site workers in 1996 and late 1995. No off-site air data were available for ATSDR review. The average concentrations of contaminants detected in on-site air will become substantially diluted as they migrate off-site, probably to levels below ATSDR's comparison values. However, if the concentrations of phosgene and aldehydes such as acrolein and formaldehyde were much higher during landfill fires than they were between fires, then the latter substances may well have contributed (along with smoke inhalation) to the respiratory symptoms reported by nearby residents.
Based on available data, ATSDR staff determined that human exposure to groundwater in the Bovoni Landfill area is not likely to occur and that the concentrations of contaminants in groundwater are currently below levels of health concern. Although no cistern water sampling data were available for review, ATSDR staff members consider it unlikely that there would be significant exposure to volatile organic compounds and polycyclic aromatic hydrocarbons in cistern water. Because of the intermittent nature of exposure to sediment and the very low likelihood that recreational users will ingest sediments in toxicologically significant quantities, the contaminants detected in sediment are not considered to be at levels of health concern.
Based on the information reviewed for this Public Health Assessment, ATSDR has made the following recommendations: (1) extinguish the underground fire at the landfill; (2) conduct air sampling, particularly downwind off-site sampling, when remedial operations at the landfill begin; (3) restrict access to the landfill more effectively; (4) install diversion valves or roof washers to prevent foreign matter on the roof, such as bird droppings, insects, stray dirt, and particulates, from entering household cisterns; (5) periodically flush out sediment and sludge that collects in the household cisterns; (6) provide health education to community members to help them understand their risk in living and working near the landfill; and (7) conduct sediment sampling in an area of the Mangrove Lagoon adjacent to the landfill.
The Bovoni Landfill is on the southeastern shoreline of St. Thomas, U.S. Virgin Islands. Please refer to Figure One, Appendix A, for a site location map. This active landfill has operated on St. Thomas for approximately 18 years and has a history of accepting municipal, industrial, and medical waste and debris from construction activities and hurricanes. Little or no separation of the waste stream occurred .
The Bovoni Landfill has been burning underground for an undetermined period. Various individuals have reported that the underground fire has been burning only a few months, 7 to 10 years, and 15 years or longer. The underground fire occasionally breaks through the surface and reportedly covers the island with black smoke. The landfill also had a "tire" fire, which erupted when piles of junked cars were ignited accidentally in March 1996. Reports of various fire events have continued during the preparation of this document, including a major surface fire of electrical cable in May 1997.
Current practices include the separation of hazardous wastes (waste oil, solvents, fuel, etc.). Medical waste is routed to an incinerator at the Roy Schneider Hospital rather than to the landfill. Environmental data are not routinely collected for the landfill. However, a recent field investigation included aerial infrared photography and collection of on-site groundwater and air samples .
In April 1996, a community group petitioned the Agency for Toxic Substances and Disease Registry (ATSDR) to evaluate the public health impact of the Bovoni Landfill. The petitioning community group's main concern was the emission of potentially harmful fumes during above-ground fire events at the landfill. The group members said residents complain about the blackish smoke and want to know what contaminants in the smoke could be causing their medical problems. The community group members also expressed concern about the landfill's overall effect on the environment. They think the landfill is damaging the adjacent Mangrove Lagoon, which they believe is a spawning area for marine life, and are concerned that fish in the area could become contaminated from the lagoon and residents could be exposed when they eat the contaminated fish. Concerns were also expressed about the amount of medical waste disposed of improperly. Further, the community group expressed concern over potentially contaminated groundwater and cistern water.
Dr. Douglas Gouzie and Danielle Langmann, ATSDR Petition Response Branch; Dr. Robert Johnson, ATSDR Exposure Investigation and Consultation Branch; and Steve Jones, ATSDR Region II Representative, participated in a site scoping visit August 1923, 1996. ATSDR staff met with various Virgin Island government health and environmental department representatives to gather information about the site. They also met with the petitioning community group to gather their health concerns and explain the petition process. Additionally, ATSDR staff met individually with several local residents and also participated in a public meeting.
During a site tour, ATSDR staff noted the conditions of the landfill and surrounding area. There was no medical waste visible on the landfill surface. Dump trucks created dust because of dry conditions. A separate hazardous waste staging area, including a black pond, was near the front gate. A large visible section (many acres) contained junked automobiles. The Mangrove Lagoon adjacent to the edge of the landfill did not have much vegetation with leaves, although most other vegetation on the island was green and leafy. Current filling seems to be in accord with normal U.S. practices, and there appeared to be adequate cover material.
Fencing was visible around most of the site, although ATSDR staff noted some waste outside the fenced area. One area where past fires were reported had visibly uneven surfaces and unknown conditions. The nearest residence borders the site, approximately 500 feet from an active section of the landfill.
ATSDR staff participated in a second site visit on August 4-7, 1997. The purpose of this trip was to provide status updates for government officials and agencies and the petitioner. Also, ATSDR staff held a public meeting to discuss the findings of the public comment version of the Bovoni Landfill Petitioned Public Health Assessment.
According to the 1990 Census of Population and Housing , the demographic statistics for locations within 1 mile of the site indicate 3,881 persons reside in 1,347 households. Of the 3,881 persons, 4.3% are white; 92.2% are black; 0.1% are American Indian, Eskimo, Aleut; 0.1% are Asian or Pacific Islander; and 3.3% are members of other ethnic groups. There are 553 children aged 6 or younger and 222 adults aged 65 and older. Please refer to Figure Two, Appendix A, for additional demographic statistics.
St. Thomas is the second largest of the U.S. Virgin Islands. The island is approximately 14 miles long and 2 to 3 miles wide . The land surface is almost entirely sloping and extends from a central ridge that runs the length of the island . Located on a peninsula on the southeast portion of the island, the Bovoni Landfill is currently the primary disposal area for island residential, commercial, and industrial wastes. A land survey of the landfill indicated that it currently extends from an elevation of approximately 22 feet above sea level to a maximum elevation of approximately 140 feet above sea level . The Mangrove Lagoon, which is hydraulically connected to the Caribbean Sea, is east of the landfill. Bolongo Bay is to the west. The Bolongo Bay area contains both residential housing and resort accommodations. Residential housing, a racetrack, and a few small businesses are north/northeast of the landfill.
Natural Resource Use
Island residents obtain fresh water from several sources: desalination plants, rooftop rain catchments that fill household cisterns, groundwater wells pumped by private water-hauling companies that fill household cisterns, and private wells. Most residents in the Bovoni Landfill area rely on the rooftop rain catchments to fill their household cisterns. Rainfall is seasonal, with rainy seasons in late summer and early fall, and a secondary wet season that usually occurs in May. Residents depend on the private water haulers to fill their household cisterns during dry periods.
The steeply sloping elevation of the landfill topography controls groundwater movement at the Bovoni Landfill, and the movement is determined to be toward the east . The western, northern and southern boundaries are approximately equivalent to the localized topographic divide, which consists of highly folded, faulted and fractured rock . Groundwater, which is replenished through rainfall, is limited to openings along the fault zones .
Health data for some geographic areas are contained in databases. Information on the number of deaths and births in a geographic location including such variables as age, sex, cause of death, birth weight and birth defects can be collected and entered into the databases. The health outcome databases make it possible to determine whether the occurrence of certain health outcomes are greater than expected. The Department of Health, Bureau of Vital Statistics, Cancer and Birth Registries, collects health outcome data for St. Thomas.
As part of the petition process, Agency for Toxic Substances and Disease Registry (ATSDR) staff have gathered health concerns from several sources. First, ATSDR gathered the health concerns of the petitioning environmental group. Then, during a public meeting on August 20, 1996, ATSDR staff noted the health concerns expressed by residents at the meeting. ATSDR staff have also noted the health concerns expressed by the Army Corps of Engineers personnel assisting in the debris reduction mission at the landfill in late 1995 and early 1996 . Further, ATSDR received letters written by concerned local residents describing a number of ailments. These concerns are summarized below and addressed in the Community Health Concerns Evaluation Section of this public health assessment. Concerns include the following:
- health ailments, such as cough, congestion, irritated throats, irritated lungs, light-headedness, headaches, nausea, chest tightness, and shortness of breath, may be attributable to landfill smoke;
- musculatory ailments, degenerative arthritis, knee problems, joint pains, stiffness, and skin rashes may be related to landfill contaminants;
- concerns over drinking and bathing with cistern water;
- concerns related to community education;
- concerns over improper disposition of medical waste; and
- concerns that the landfill may be damaging the Mangrove Lagoon.