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PUBLIC HEALTH ASSESSMENT

TUTU WELLFIELD
ST. THOMAS, ST. THOMAS COUNTY, VIRGIN ISLANDS



SUMMARY

The Tutu Wellfield National Priorities List (NPL) site is in east-central St. Thomas, U.S. Virgin Islands. Tutu is located in the Upper Turpentine Run Basin, Anna's Retreat, St. Thomas. Twenty-two wells in the Turpentine Run Basin contain at minimum a trace of volatile organic contaminants. The site consists of most of the Turpentine Run Basin, with multiple sources and properties. Therefore, the entire basin or wellfield is considered the site.

In July 1987, a strong petroleum odor was detected in the Tillet well, one of several major commercially owned supply wells in the area (see Figure 2, Tillet Property). At that time, the well was used as a public drinking water source throughout the island (primarily the eastern side). The Virgin Islands Department of Planning and Natural Resources (VIDPNR) requested the U.S. Environmental Protection Agency (EPA) to sample that well and other wells in the area. From July through September of 1987, the EPA Technical Assistance Team (TAT), Roy F. Weston, Inc., sampled approximately 24 wells and 123 cisterns. Volatile and chlorinated hydrocarbons including benzene; toluene; 1,2-trans-dichloroethene (DCE); trichloroethene (TCE); and tetrachloroethene (PCE) were detected in several of the wells. The types of wells included public supply wells, institutional wells, commercial wells, and private domestic wells. Several of the cisterns also contained volatile and chlorinated hydrocarbons.

The Phase II Remedial Investigation report for this site concluded that there are several distinct plumes of groundwater contamination and several properties which have contributed to the groundwater contamination within the Tutu Wellfield NPL site. Several properties were identified in the Phase II report as sources of petroleum-related groundwater contamination (i.e., Texaco Tutu Service Station, Esso Tutu Service Station, and Kentucky Fried Chicken [former Home Petroleum]). In addition, the Curriculum Center (former Laga Building) and O'Henry Dry Cleaners were identified in the Phase II report as sources of chlorinated volatile organic compound (VOCs) groundwater contamination. The report also concluded that there is a moderate to high probability that dense nonaqueous phase liquids (DNAPL) are present in the fractured bedrock (the bedrock from which the local wells withdraw water).

The Agency for Toxic Substances and Disease Registry (ATSDR) has concluded that the Tutu Wellfield National Priorities List (NPL) site, St. Thomas, U.S. Virgin Islands, poses a public health hazard for past, present and possible future ingestion of contaminated groundwater. Based upon the site history, ATSDR has estimated that people may have ingested contaminated groundwater for up to 20 years (a worse case assumption). An increased risk of cancer might exist for those people, as well as for people who are currently using contaminated groundwater, or who may use it in the future. There is a strong likelihood that commercial and private wells may currently be open or may be opened in the future by individuals to supplement water supplies during water shortages. If those events occur, an increased risk of cancer might exist. In addition, wells that are not currently contaminated and wells that may be constructed in the future have the potential to become contaminated from the groundwater plume. An increased risk of cancer may also exist in that case.

A public health hazard exists for possible inhalation and dermal exposure to volatile organic compounds (VOCs) when contaminated groundwater is used for secondary purposes inside private homes (i.e., washing, showering, flushing. and bathing). The possibility exists for adverse health effects to develop after exposure to VOCs through secondary exposures. In addition, the possibility exists that these wells could be used for potable sources. There is also a chance that the concentrations in these wells could increase if a dense nonaqueous phase liquids (DNAPL) enters the wells. If that occurs, it could increase the chance that adverse health effects could develop.

If people did not receive contaminated potable water for more than 10 years, their chance of developing cancer would be reduced significantly.

The remedial alternative selected by the U.S. Environmental Protection Agency would require all private and commercial wells within the area of contaminated groundwater to be closed. The remedial alternative would also require the treatment of the contaminated soil and groundwater. If implemented, the proposed remedial plan should stop any on-going exposures and prevent any future exposures to site-related contaminants and would protect the health of the public.

ATSDR has made recommendations to (1) reduce and prevent exposure to contaminants, (2) implement health follow-up and other activities, and (3) improve certain toxicologic data gaps.

BACKGROUND

The Agency for Toxic Substances and Disease Registry (ATSDR) has evaluated the public health significance of this site. More specifically, ATSDR has determined whether health effects are possible and will recommend actions to reduce or prevent possible adverse health effects. ATSDR, in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) to conduct health assessments at hazardous waste sites.

A. Site Description and History

The 108 acre Tutu Wellfield site, in a mountainous area of eastern central St. Thomas, U.S. Virgin Islands, consists of groundwater contamination from both known and unknown sources. The site consists of most of the Turpentine Run basin, with multiple sources and properties. The Tutu section is located in the estate known as Anna's Retreat, in the Upper Turpentine Run Basin (see Appendix 1, Figure 1). The site boundaries are not clearly defined, but an approximate area is shown in Appendix 1, Figure 2. This figure also depicts the businesses and other buildings comprising the site.

In July 1987, a strong petroleum odor was detected in the Tillet well, one of several major commercially owned supply wells in the area (see Figure 2, Tillet Property). At that time, the well was used as a public drinking water source throughout the island (primarily the eastern side). The Virgin Islands Department of Planning and Natural Resources (VIDPNR) requested the U.S. Environmental Protection Agency (EPA) to sample that well and other wells in the area. From July through September of 1987, the EPA Technical Assistance Team (TAT), Roy F. Weston, Inc., sampled approximately 24 wells and 123 cisterns. Volatile and chlorinated hydrocarbons including benzene; toluene; 1,2-trans-dichloroethene (DCE); trichloroethene (TCE); and tetrachloroethene (PCE) were detected in several of the wells. The types of wells included public supply wells, institutional wells, commercial wells, and private domestic wells. Several of the cisterns also contained volatile and chlorinated hydrocarbons.

Compounds were detected above and below the maximum permissible concentration levels, 10-Day Health Advisory Levels, and Removal Action Levels. Thirteen commercial wells (including the Tillett well) and five private wells were subsequently closed and alternative plans, which included trucking water to the area, were initiated.

In July 1987, VIDPNR issued an Administrative Order of Consent to the Tutu Texaco Service Station in order to investigate petroleum release from their underground storage tanks. Texaco was also ordered to stop all work which could disturb the potentially contaminated area. In 1987, Esso Tutu Car Care Center was also issued a similar Administrative Order (1).

On February 19, 1992, the Tutu Environmental Investigation Committee (comprised of Texaco Caribbean Inc. and Esso Virgin Island, Inc.) signed an agreement with EPA to perform an Remedial Investigation/Feasibility Study (RI/FS) at the Tutu Wellfield site (2). The RI/FS was conducted according to EPA guidelines and with EPA oversight. The RI/FS field activities were conducted by Geraghty & Miller, Inc. and Soil Tech, contractors for the Tutu Environmental Investigation Committee.

The Tutu Wellfield site was proposed to EPA's National Priorities List (NPL) in February 1992. On September 29, 1995, EPA finalized the listing of this site on the NPL. The NPL is the nationwide list of hazardous waste sites that qualify for federal Superfund cleanup dollars.

In June 1993, EPA identified 12 potentially responsible parties (PRPs) (1). Below is a description of the properties of the PRPs (see Appendix 1, Figure 2 for locations).

  • Tutu Texaco Service Station

    The Tutu Texaco service station has been in operation since 1964 selling gasoline and diesel fuel and servicing automobiles (2,3). It is located north of Tillett on Highway 38. This facility has contributed to groundwater contamination through both unleaded and leaded gasoline underground storage tanks (USTs). Three 4,000 gallon gasoline USTs were taken out of service in 1980 due to suspected leaks and mechanical integrity test failure. Those three tanks were removed in September 1988. Large and small holes were discovered in the tanks during the investigation. Strong odors of petroleum hydrocarbons and air readings above background were detected on the HNu Photoionizer during the excavation.

  • Esso Tutu Service Station

    The Esso Tutu car care center has been in operation since 1970 selling gasoline and servicing automobiles (2). It is located southwest of Tillett on Highway 438 (Appendix 1, Figure 2). This facility has contributed to the groundwater contamination through both leaded and unleaded gasoline USTs. In 1987, a petrotite leak test indicated that the structural integrity of the unleaded gasoline UST was questionable. In June 1989, tanks were removed from the property. Slight odors of petroleum, oily sheens in the excavation pit, and readings above background on the HNu Photoionizer were detected during the tank removals (1).

  • Ramsay Motor Company

    This facility contributed to the groundwater contamination through a UST and 55-gallon drums. Vehicle maintenance and repairs have been conducted at this facility since 1978. During a 1989 site reconnaissance, it was observed that the drums were not properly contained and small amounts of oil appeared to be leaking. Oil stains and pools were evident on the grounds. In addition to waste oil, antifreeze, and a large variety of solvent-based auto flushes, treatment, degreasers, cleaners, and lubricants were also present at the facility. The hazardous materials found in those products included xylene; naphtha; ethoxylated nonyl phenol; propane; butyl cellosolve; 1,1,1-trichloroethane; PCE; petroleum distillates; and ethylene glycol (1,4).

    Samples collected in August 1987, September 1988, June 1989, and July 1989 indicated contamination by volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) (5,6).

  • Antilles Auto Parts

    This facility contributed to soil and groundwater contamination via 55-gallon drums (waste oil and raw material); and messy house-keeping of service yard and bays (7,8). Vehicle maintenance and repairs have been conducted at this facility since 1992.

  • Virgin Island Housing Authority (VIHA)

    Formerly Tropical Motors (automobile dealership), the facility contributed to the groundwater contamination through a UST. Hydraulic fluid was reportedly stored in the tank. The VIHA building contains a mechanic's shop and storage area for pesticides and other unidentified chemicals (9). VIHA has used this facility since 1978.

    In August 1987, waste oil samples collected from a UST were submitted for analysis. Benzene, toluene, ethyl benzene, and total xylene were detected (10).

  • Curriculum Center (former LAGA Building)

    This property was formerly a clothing manufacturing plant (LAGA Textile Company, 1969-1979, and Panex Co., 1979-1982). The facility contributed to the groundwater contamination via abandoned 55-gallon drums and other waste disposal practices. During a site reconnaissance, it was observed that the abandoned drums were not contained and were deposited in a haphazard manner on the property. These drums were badly corroded or perforated and some were empty. Access to these drums and to the property was not restricted. In June 1989, Camp Dresser and McKee (contractors hired by EPA to determine site contamination) observed that drums were still on the property. In addition, past operations at the facility include the extensive use of PCE (11,12,13,14). In August 1992, a drum area was discovered and soil samples were taken, as reported in the On-site Contamination subsection of this document.

    Since 1982, the VI Department of Education has used the facility for a library, warehouse for school supplies, and offices.

  • O'Henry Cleaners

    The O'Henry Cleaners has been operation since 1962. This facility has contributed to the groundwater contamination through a leaching pit, a sump holding tank, a raw material (PCE) storage area, above-ground fuel tanks, drains, effluent discharges for steam condensate from the presses and the clothes dryer, and 5-gallon containers of spent PCE residue or filters. Not much information about the containment of these waste units is known, but PCE spills have reportedly occurred. The preliminary assessment (PA) indicates that O'Henry uses 1.5 to 1.75 gallons of PCE per month and has disposed of the PCE residues and spent filters at a "local dump site" in the past. The PA also indicates that a small amount of PCE residue and waste was possibly disposed of on site in the past (1,4,8,12,15). Other products used on-site include dry cleaning fluids such as 2-butoxyethanol, hexylene glycol, hydrofluoric acid, degreasers, unspecified volatile solvents, and dye strippers (1,16).

    In September 1988, PCE was detected in a soil sample collected and submitted for analysis. In June 1989, three surface soil samples collected and submitted for analysis indicated the presence of TCE and PCE.

  • Tillet Gardens

    This facility contributed to the groundwater contamination through paint containers, a raw material storage area, floor drains, and evaporation pit. Dry residue was disposed at a local dump (1). Tillet Gardens has been operation since 1960.

    In November 1987, a soil gas survey (used to determine the amount of VOCs present in soil) in the area detected hydrocarbons, including PCE, trichloroethane, and TCE in the Tillet Garden area (11). In September 1988, one soil sample was collected and submitted for analysis; xylene was detected at a low estimated concentration (17).

  • Western Auto

    The Western Auto store operated in the Four Wind Plaza from the late 1970's until 1995. This facility contributed to the groundwater contamination through a leaking UST (18).

In April 1995, the Tutu Environmental Investigation Committee issued the Phase II Remedial Investigation report (18). The report contained the results of the final phase of the RI for this site. During this investigation, several additional properties (beyond the original nine PRPs) were evaluated to determine if they may have contributed to the groundwater contamination. Of those new properties, only the Western Auto Store in the Four Winds Plaza (see Appendix 1, Figure 2) was found to have any environmental contamination (i.e., soil) associated with it operations.

The Phase II Remedial Investigation report concluded that there are several distinct plumes of groundwater contamination and several properties which have contributed to the groundwater contamination within the Tutu Wellfield NPL site (18). Several properties were identified in the Phase II report as sources of petroleum-related groundwater contamination (i.e., Texaco Tutu Service Station, Esso Tutu Service Station, and Western Auto). In addition, the Curriculum Center (former Laga Building) and O'Henry Dry Cleaners were identified in the Phase II report as sources of chlorinated VOCs groundwater contamination. The report also concluded that there is a moderate to high probability that dense nonaqueous phase liquids (DNAPL) are present in the fractured bedrock (the bedrock from which the local wells withdraw water).

(Note: A DNAPL is a localized lens or mass of organic chemicals which have not been dissolved in water. The concern at the Tutu Wellfield NPL site is that relatively small volumes of DNAPL may have moved into the bedrock and is moving as droplets or globules within the rock fractures of the groundwater aquifer. These droplets or globules are very difficult to remove and, if present, will continue to be a source of contamination for any water supply wells used in the area).

On August 23 through September 22, 1995, EPA made available for public comment the RI/FS reports and the Proposed Plan to remediate the environmental contamination at the Tutu Wellfield NPL site. Because of delays caused by Hurricane Marilyn EPA held another public comment period for the Proposed Plan from February 12 through March 13, 1996. The Proposed Plan calls for the in-situ treatment of contaminated soils at the Texaco Tutu Service Station, Esso Tutu Service Station, O'Henry Dry Cleaners, and Curriculum Center. In addition, the EPA proposes to excavate and dispose of some of the contaminated soil at the Four Winds Plaza/Western Auto, O'Henry Dry Cleaners (as needed), and Curriculum Center in an off-island facility. In order to clean the contaminated groundwater, EPA proposes to install a groundwater recovery well system which would pump the contaminated water to a central treatment facility. This proposed plan would require the decommissioning of the existing domestic and commercial wells within the confines of the groundwater plume.

B. Site Visit

Dr. Adrienne L. Hollis and Ms. Laura Barr from ATSDR Headquarters, along with Mr. Steven Jones, ATSDR regional representative, visited the site area from December 9-11, 1992. They were accompanied on the site visit by representatives from VIDPNR. On the first and second days of the site visit, the team inspected the site and observed the following:

    Representatives from ATSDR and VIDPNR toured the wells located in the site area. A number of the wells were closed, as ordered by VIDPNR. A few of the wells were in use, for both potable and secondary use, including flushing and/or washing. For the majority of the residents in Tutu, drinking water is usually obtained from cisterns, which are used to collect rainwater, or from commercial water trucks.

    One of the cisterns near the VIHA was in an unfenced area where children and animals could gain access. Excrement from cows was observed on top of the cistern, and the cistern was not properly covered. That cistern was being used to supplement water to residents of the VIHA public housing because the Water and Power Authority (WAPA) was rationing water in the area due to their inability to locate a leaking water pipe.

On March 4 through 6, 1996, Mr. Sven E. Rodenbeck, ATSDR Headquarters, and Mr. Steven Jones, ATSDR Region II, visited the site area. The may purpose of the site visit was to attend the March 5 public meeting EPA held to discuss the proposed remedial plan. ATSDR was at the meeting to address any questions or concerns about the Tutu Wellfield Public Health Assessment (the Assessment was available for Public Comment from January 29 through February 28, 1996).

C. Demographics, Land Use, and Natural Resource Use

1. Demographics

Tutu Wellfield is situated in a mountainous area of St. Thomas, U.S. Virgin Islands. Based on 1980 data, the island population is estimated at 44,170 persons (19) with approximately 11,000 people residing within a 1-mile radius of the site (3). As with most of todays modern society, the population within the Tutu Wellfield area tends to be fairly transient (i.e., people do not reside in one home very long). Approximately 1,500 people reside in the VIHA housing development located at the northern end of the Tutu Wellfield NPL site. The 1990 population for the island was estimated at 50,520. A large majority of the population lives in the town of Charlotte Amalie, 2.5 miles west of the site (3).

2. Land Use

St. Thomas, the second largest of the U.S. Virgin Islands, is approximately 14 miles long and 2 to 3 miles wide (21). Tutu is located in the Upper Turpentine Run Basin, in the estate of Anna's Retreat, St. Thomas. An intermittent stream (a stream flowing only part of the time such as after a rainstorm) leading to Turpentine Run is a few hundred feet southwest of the site. Turpentine Run, also an intermittent stream, flows southward to Mangrove Lagoon which is hydraulically connected to the Caribbean Sea. The Atlantic Ocean lies approximately 1-mile north of the island. The surface water of Mangrove Lagoon, used for swimming, fishing, and boating, is approximately 3 miles from the site. There is a coastal mangrove wetland, the Mangrove Swamp, 2.5 miles downstream from the site (3). This swamp has been designated as a preservation area by the VIDPNR.

The Tutu Wellfield area includes large housing developments owned by the VIHA as well as several elementary schools. Approximately 2,000 students attend Joseph Gomaz Elementary School (northwest of the LAGA building) and about 500 students attend the Seventh-Day Adventist Church School.

3. Natural Resource Use

Fresh water is a valuable resource at St. Thomas. It is obtained by four means: 1) desalination plants, 2) roof-top rain catchments, 3) groundwater wells pumped by private water hauling companies that fill-up household cisterns, and 4) private wells. WAPA's desalinization plant provides water to the town of Charlotte Amalie and to some of the people residing in the Tutu area (3). During dry seasons, WAPA may supplement desalinated water with groundwater which is not contaminated. Most of the hotels and resorts on the island either have their own desalinization plants or obtain water from WAPA. Most of the homes outside of Charleotte Amailie generally obtain all of the water they need for household needs via roof-top catchments. Homeowners may need to supplement their roof-top catchments once or twice annually with water obtained from a private water hauling company; more often during drought conditions. However, people who reside on the eastern portion of St. Thomas general have to rely-upon private water hauling companies for their water supply because that portion of the island does not receive very much rain.

Groundwater, replenished through rainfall, is a valuable resource in the Turpentine Run Basin. The Upper Turpentine Run Basin contains one of the most productive and heavily used aquifers on St. Thomas (11). There are private, commercial, institutional, and public wells. Most private homes in the Turpentine Run Basin use cisterns (usually roof-top catchments) as their primary drinking water source and groundwater wells for secondary purposes such as washing, flushing, showering, and gardening.

There were a number of wells in the Tutu Wellfield NPL site that were used for commercial purposes. Groundwater was pumped by water haulers for sale to domestic users (private homes) as well as sold in bottles to hotels, restaurants, and supermarkets (3). It was pumped into cisterns to augment the rainwater collected from roofs. Groundwater is also used for industrial purposes (3). All of the contaminated commercial wells within the Tutu Wellfield NPL site used by the water haulers were shutdown in 1987.

The geology consists of a volcanic sequence which was probably extruded on the ocean floor (21). Most of Tutu Wellfield lies in bedrock of the Louisenhoj Formation, which consists of tuff, breccia, and a few thin beds of limestone (22). Due to the faulting and jointing patterns in the rock, prime zones of groundwater recharge and availability follow valleys, such as Turpentine Run Basin. St. Thomas has a water table which at depth roughly parallels the land surface; groundwater is subject to recharge from rainfall. The direction of groundwater flow in the Turpentine Run Aquifer is south/southeast. Depth to groundwater ranges from 5 to 60 feet below ground surface (3).

D. Health Outcome Data

Health outcome data were not evaluated for this site because no previous health studies on the population around the site were identified during the gathering of data and information for this public health assessment. In addition, the Virgin Islands do not have a centralized cancer registry which could have possibly been used to determine if the occurrence of cancer near the Tutu Wellfield NPL site is more than what would be expected.

COMMUNITY HEALTH CONCERNS

As part of the investigation of the site, ATSDR staff held two informal, one-on-one public availability sessions to learn about citizens' site-related concerns. The sessions were advertised in The Daily News, the St. Croix Avis, and The Tradewinds. On Thursday, December 10, 1992, and on Friday, December 11, 1992, public availability meetings were held from 7:00 to 9:00 p.m. These sessions were held at the Lutheran Church of the Reformation, in Tutu. Only one individual attended. That individual was planning to purchase property in the area down gradient of the plume, and was concerned with the effect of the plume on property value. ATSDR suggested that this individual attend EPA's public meeting to gather information on the plume. No community health concerns were expressed by citizens or by VIDPNR during these availability sessions.

During the March 5, 1996, EPA public meeting that ATSDR attended, several community health concerns were provided by the public. The concerns are summarized below and will be addressed in the Community Health Concerns Evaluation section of this public health assessment.

  1. Is leukemia the only type of cancer likely to be increased from exposure?

  2. Were health records/data examined to determine whether there is a higher incidence of cancer in the St. Thomas population than other areas?

  3. How can I prevent exposure to site-related contaminants?

  4. Will a health study be conducted to determine if the incidence of cancer is higher than what would be expected?

COMMUNITY RELATIONS ACTIVITIES CONDUCTED BY EPA

EPA began its community relations activities in February 1992, by conducting interviews with area residents and property owners, personnel from the VI Department of Health and the Department of Planning and Natural resources, and a member of the VI legislature. In May 1992, EPA held its first public meeting on the site in Anna's Retreat. At the meeting, EPA presented the work plan for the remedial investigation/feasibility study, provided interested parties with an overview of Superfund, and discussed the risk assessment investigations undertaken and opportunities for public involvement. In April 1992, EPA prepared its first Community Relations Plan (CRP) for the site. During this time, EPA also prepared and distributed two fact sheets to the community and established an information repository at the Curriculum Center. EPA conducted a second set of interviews in October 1994. According to EPA, community concerns regarding the Tutu Wells site focus on these issues: the notification of additional responsible parties and their liability, the interpretation of sampling results and the continued use of well water, the extent of contamination and the need to work quickly, and the restoration of the Island's natural resources. Based on this information, a revised CRP was released in March 1995. In February 1995, EPA mailed letters to residential well owners in Tutu, explaining their well sampling results. An informal meeting was held in April 1995 to explain the results of the remedial investigation and the range of alternatives that will be evaluated in the upcoming feasibility study. On March 5, 1996, EPA held a public meeting to present the proposed remedial plan.



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