| ATSDR's evaluation is an assessment of public health (i.e., whether it is safe to eat Vieques fish and shellfish). This document is not an ecological assessment of the integrity of the natural systems on Vieques. |
From July 16-20, 2001, these commonly consumed fish and shellfish were collected from six locations on Vieques. Fish were collected from reefs to the north of the LIA (Location 1), from a sunken Navy vessel to the south of the LIA (Location 2), from reefs to the south of Esperanza (Location 3), from reefs to the north of Isabel Segunda (Location 4), from a fish market in Isabel Segunda (Location 5), and from reefs to the west of the Laguna Kiani Conservation Zone on the west end of Vieques (Location 6). Lobsters were collected from Locations 1, 3, and 5. Conch were collected from seagrass beds located in close proximity to Locations 1, 2, 3, and 6. Land crabs were collected from Locations 1, 2, and 6. Fiddler crabs were collected from Locations 1 and 2.
During the sampling event, the EPA/ERT divers noted that all sample locations supported diverse populations of marine organisms that appeared healthy and that with very few exceptions, most of the organisms collected appeared to be healthy.
Several metals were detected in the fish and shellfish from Vieques. Using this data, ATSDR evaluated three specific exposure situations for both adults and children living on Vieques:
| Heavy metals were detected in the fish and shellfish, however, the concentrations were too low to pose a human health concern. |
ATSDR concluded that:
In May 1999, a resident of Isla de Vieques (Vieques), Puerto Rico, requested (petitioned) the Agency for Toxic Substances and Disease Registry (ATSDR) to determine whether hazardous substances from the detonation of munitions at the United States Navy (Navy) bombing range on the island pose a public health threat. In August 1999, ATSDR conducted an initial site visit to Vieques to meet with the petitioner, tour the island and bombing range, and gather available environmental data. As a result of this site visit, ATSDR accepted the petition and since has been investigating public health concerns related to the Navy's training activities on Vieques.
ATSDR is responding to this petition in a series of public health assessments (PHAs). PHAs examine chemicals that enter the environment, how the chemicals move through the environment, and the levels of chemicals that residents might encounter. ATSDR then uses this information to determine whether residents are exposed to levels of contamination that might cause health problems.
This PHA addresses the public health implications from eating fish and shellfish from the coastal waters and near shore land of Vieques. The fish and shellfish were analyzed for explosives compounds and heavy metals. Explosives compounds are not naturally occurring in fish and shellfish. Whereas, heavy metals are commonly detected in fish and shellfish tissue because seafood tends to accumulate metals that are naturally present in the environment (ATSDR 1999a; ATSDR 2000a; EPA 2001a). Therefore, eating fish can be a major source of one's exposure to metals. In fact, many states have issued advisories against eating fish or shellfish because of the metal content (EPA 2000). ATSDR focused this evaluation on the types of fish and shellfish that the community commonly catches and consumes (based on research by Universidad Metropolitana (Caro et al. 2000), discussions with the petitioner and residents of Vieques, and information provided in the Vieques Special Commission Report (Government of Puerto Rico 1999 as cited in Navy 2000b)).
Vieques is the largest offshore island in the Commonwealth of Puerto Rico. Vieques is 20 miles long, 4.5 miles at its widest point, and about 33,000 acres (or 51 square miles) in area. Figure 1 shows the location of Vieques and surrounding islands. As the figure illustrates, the nearest island to Vieques is the main island of Puerto Rico, approximately 7 miles to the west. The island of Culebra is roughly 9 miles north. St. Thomas, St. John, St. Croix, and other US Virgin Islands are all 20 miles or more northeast and southeast of Vieques.
The detailed map in Figure 2 illustrates land use in Vieques. The western portion of Vieques is the former Naval Ammunition Support Detachment (NASD). Prior to May 2001, the Navy used this 8,200 acres for limited Navy operations (e.g., ammunition storage, rock quarry, communication facilities, and Navy support buildings) (IT Corporation 2000). In May 2001, the Navy transferred most of the NASD to the Isla de Vieques, the Puerto Rico Conservation Trust, and the US Department of the Interior, but retained about 100 acres of the former NASD lands for radar and communication facilities (Navy 2001a). Some NASD areas were leased to local farmers for cattle grazing and other agricultural purposes (see Picture 1).
The central 7,000 acres of Vieques houses the entire residential population of the island, mostly in the towns of Isabel Segunda and Esperanza. Vieques land uses include residential, agricultural, commercial, and industrial. In the past, sugarcane was the principal crop. Other crops have included coconuts, grains, sweet potatoes, avocados, bananas, and papayas. In the 1960s and 1970s, manufacturing was important for the economy, beginning in 1969 with the construction of the General Electric plant (Bermudez 1998). But currently, only minimal manufacturing takes place on the island. Isabel Segunda and Esperanza, however, are home to commercial fishing fleets, and recently tourism has been increasing in economic importance.
Until May 2003(1) , the Navy owned roughly the eastern half of Vieques, which is divided into two sections: the Eastern Maneuver Area (EMA) and the Atlantic Fleet Weapons Training Facility (AFWTF).
ATSDR examines demographic data (i.e., population information) to determine the number of people potentially exposed to environmental chemicals and to determine the presence of any sensitive populations, such as women of childbearing age, children, and the elderly. Demographic data also provide details on population mobility which, in turn, helps ATSDR evaluate how long residents might have been exposed to environmental chemicals.
Table 1 summarizes the 2000 US Census Bureau demographic data for Vieques. As the table shows, the 2000 Census reported that 9,106 people live on Vieques. This figure includes residents on both the residential lands and Navy property. Table 1 also specifies the number of residents in three potentially sensitive populations. According to several anecdotal accounts, the population of Vieques is not highly mobile; many are lifelong residents of the island.
As noted previously, most of the residents of Vieques live in the two largest towns on the island, Isabel Segunda and Esperanza (see Pictures 8 and 9). Although these towns are located relatively close to the Navy property, they are several miles removed from the LIA. Approximately 7.9 miles of Navy owned land provides a buffer zone between the LIA and populated areas of Vieques.
Vieques lies in the path of the easterly trade winds (i.e., winds blowing from east to west). The climate is tropical-marine, with temperatures averaging about 79 Fahrenheit (26.3 Celsius). Annually, the temperature ranges from an average of 76 Fahrenheit (24.6 Celsius) in February to 82 Fahrenheit (28 Celsius) in August. The average amount of precipitation is about 45 inches a year. The western part of the island receives a higher amount of rainfall (about 50 inches a year) than the eastern part (about 25 inches a year). The rainy season is from August through November while the remainder of the year is drier. Tropical storms are common from June to November (NCDC 1985-1994; Torres-Gonzalez 1989).
African Dust Storms
Through the natural occurrence of African dust storms, Vieques, together with the mainland of Puerto Rico and other Caribbean islands, receive an increase of airborne dust particles in the summer. Each year, large quantities of dust from the Sahara Desert and Sahel region in Africa are transported at high altitudes to the Caribbean Sea and southeastern United States. These dust storms can transport minerals, chemicals, bacteria, fungus spores, and possibly viruses and insects. Recent studies have begun to link declining coral reef health with fungi and bacteria found in African dust (e.g., the soil fungus, Aspergillus, causes a disease in sea fans; USGS 2000). The potential for adverse health effects to occur from African dust storms will be addressed in the Community Health Concerns Section of the Air Pathway Evaluation PHA.
Vieques was formed from igneous and volcanic rock, mostly granodiorite, quartz diorite, and some lavas which created the bedrock of the island. On most of the western half as well as the central portion of the eastern half of the island, the bedrock is exposed and weathered. Because| Alluvial deposits are sediment deposited by flowing water. They generally consist of a mixture of gravel, sand, silt, and clay. |
The Navy has occupied portions of Vieques since 1941. In 1960, the Navy established targets on Vieques and began bombing practice (Navy 1990). The use of the LIA for air-to-ground and ship-to-shore training increased after the closing of the Culebra Island range in the mid-1970s.
Many different types of explosive and non-explosive ordnance (e.g., bombs, flares, rockets, projectiles, and small arms) have been used at Vieques. ATSDR's PHA focused on the soil pathway describes the types of military ordnance in greater detail (ATSDR 2003). Generally, Naval training exercises are most frequent in February and August with fewer exercises in April, May, November, and December. Range utilization statistics data from 1983 to1999 indicate that the Navy and other parties conducted exercises on Vieques between 159 and 228 days per year, with the total number of days not varying considerably from one year to the next. On average, 1,862 tons of ordnance were used at Vieques annually between 1983 and 1998. This ordnance, on average, contained 353 tons of high explosives (Navy 1999). ATSDR's PHA focused on the air pathway will describe ordnance use on Vieques in greater detail.
Two types of explosives were commonly used at Vieques (Young 1978). One explosive is made from organic nitrated compounds (i.e., only carbon, hydrogen, oxygen, and nitrogen). Examples include 2,4,6-trinitrotoluene (TNT), cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine (HMX), tetryl, Explosive D, Composition B (RDX and TNT), Octol (HMX and TNT), and Composition A-3 (RDX and wax). The second kind of explosive contains aluminum in addition to the organic nitrated compounds. Examples include Tritonal (TNT and aluminum), H-6 (TNT, RDX, and aluminum), and Torpex (TNT, RDX, and aluminum).
Live ordnance has not been used on Vieques since April 19, 1999, when two 500-pound bombs were accidentally dropped near an observation post (OP-1) on the LIA, killing a civilian guard. In January 2000, the decision was made that the Navy could resume training on Vieques. The training is limited to 90 training days per year and the use of nonexplosive ordnance only. In May 2000, the Navy resumed training.
Since its 1999 receipt of the petition requesting an evaluation of public health issues on Vieques, ATSDR has worked extensively to characterize the extent of environmental contamination and potential health effects and to respond to community needs. The following is a summary of ATSDR's past involvement on Vieques:
In addition to the previous list of activities on Vieques, ATSDR has assessed the following public health issues:
III. PREVIOUS RESEARCH
This section of the PHA summarizes research previously conducted on Vieques that is directly related to the fish and shellfish sampling conducted by ATSDR and EPA/ERT. The next section of the PHA (Section IV) provides more details about ATSDR's sampling effort.
Summary
In November 1999, researchers from Casa Pueblo de Adjuntas, in cooperation with the Biology Department of Recinto Mayaguez at the University of Puerto Rico, sampled male fiddler crabs (Uca pugnax rapax) from Icacos and Anones Lagoons in the LIA and from Puerto Mosquito just east of Esperanza. The purpose of the research was to assess the potential transport of metals from the impact area to other ecosystems.
| Biomagnification is an increase in the concentration of a chemical as the substance moves through the food chain. |
Conclusions
This research established that fiddler crabs contained evidence of heavy metals. However, fiddler crabs are not known to be a species that are eaten by the residents of Vieques. While the data from this report may be useful to evaluate ecological contamination, it has limited utility when trying to extrapolate into the human food chain. To evaluate human exposures to edible land-based shellfish, ATSDR sampled and analyzed land crabs (a species known to be consumed by the residents) during the fish and shellfish investigation in July 2001. The remainder of this PHA details ATSDR's sampling effort (Section IV) and evaluates whether eating land crabs, among other fish and shellfish species, would result in harmful health effects (Section V).
Summary
Between December 1999 and April 2000, researchers from the School of Environmental Matters, Universidad Metropolitana, collected fish from fish markets on the northern and southern (Esperanza) coasts of Vieques and from the Parquera fish market in Lajas on the western side of the mainland of Puerto Rico. The focus of the research was to identify potential heavy metal contamination in fish species that are commonly eaten by the residents of Vieques.
To identify the most frequently consumed species, researchers administered a questionnaire to Vieques residents asking about their dietary habits. Fifty-one residents responded to the questionnaire. Of these, 10 people (19.6%) reported to eat fish never or occasionally, 24 people (47%) 1-2 times a week, 9 people (17.6%) 3-4 times a week, and 8 people (15.7%) five or more times a week. Based on responses to the questionnaire, the most commonly consumed species of fish include: colirrubia (yellow tail snapper, Ocyurus chrysurus), mero cabrilla (red hind, Epinephelus guttatus), peje puerco (triggerfish, Balistes sp.), sierra (cero, Scomberomorus regalis), capitán (not identified), cotorro (parrotfish, Scaridae family), chapín (trunkfish, Lactophrys sp.), bonito (skipjack tuna, Euthynnus pelamis), negra (blackfin snapper, Lutjanus buccanella), dolorado (not identified), chillo (silk snapper, Lutjanus vivanus), boquicolorao/ronco (white grunt, Haemulon plumieri), and sama (mutton snapper, Lutjanus analis).
Researchers collected a total of 78 fish--35 fish from fish markets in northern Vieques, 17 fish from fish markets in Esperanza, and 26 fish from fish markets in the Parquera area on the mainland of Puerto Rico. Species included: arrayao (lane snapper, Lutjanus synagris), boquicolorao, colirrubia, cotorro azul (blue parrotfish, Scarus coeruleus), cotorro rojo (stoplight parrotfish, Sparisoma viride), cotorro verde (redband parrotfish, Sparisoma aurofrenatum), mero cabrilla, mero mantequilla (coney, Epinephelus fulvus), and salmorete de altura (goatfish, Mullidae family). Fish fillet and skin samples were tested for arsenic, cadmium, lead, mercury, selenium, and zinc.
The researchers concluded that "based on the data obtained...we were not able to verify our hypothesis of potential bioaccumulation in the fish...there is no clear relationship between fish weight and size and their metal content" (Caro et al. 2000). They reported "high concentrations" of arsenic, mercury, selenium, and zinc; but low or no concentrations of cadmium and lead in the fish tissue samples. Please see Tables 3 and 4 for a summary of their analytical results.
Conclusions
| The use of the term "high concentration" is relative to the basis of comparison (i.e., what the concentration is being compared to). ATSDR concluded that the chemical concentrations are not high when compared to health-based values. Whereas, Universidad Metropolitana had a different basis of comparison when they reported their results. |
This research provided valuable information about the dietary habits of the residents of Vieques, specifically how often people are eating fish and what species. This information was used throughout ATSDR's public health evaluation. In addition, ATSDR evaluated whether the concentrations reported would result in harmful health effects for people consuming fish from the sampled fish markets(2). Based on this data, ATSDR determined that it is safe to eat fish from the fish markets in northern Vieques, Esperanza, and the Parquera area on the mainland of Puerto Rico on a daily basis (i.e., all of the concentrations reported by Universidad Metropolitana are too low to be of health concern). Please see Section V. Evaluation of Fish and Shellfish from Vieques and Appendix D for more details on the methods and assumptions ATSDR used to estimate human exposure doses and determine health effects.
Summary
In July 2001, US Fish and Wildlife Service (FWS) personnel sampled land crabs and fiddler crabs from two solid waste management units (SWMUs) in west Vieques (the former NASD) and from Sandy Point National Wildlife Refuge in St. Croix, as a control. The samples are whole body and were analyzed for pesticides and metals. The purpose of the research was to collect preliminary data about the level of contamination in the prey base (land crabs and fiddler crabs) for some aquatic birds (e.g., herons and egrets). FWS provided the analytical data to ATSDR for inclusion in this health assessment (FWS 2001a, 2001b). Please see Tables 5 and 6 for summaries of the fiddler crab and land crab data, respectively.
Conclusions
This research established that fiddler crabs and land crabs contained some heavy metals and pesticides. The results were not available prior to ATSDR's sampling in July 2001. In accordance with the objectives of this research, the data from the report are useful to evaluate ecological contamination. However, this research cannot easily be converted for evaluating human health| It is standard protocol to analyze the whole body of organisms when evaluating ecological concerns and fillets/edible portions when evaluating human health concerns |
IV. ATSDR'S FISH AND SHELLFISH SAMPLING
The residents of Vieques are concerned that military training activities at the LIA are adversely affecting their health. Previous studies have reported "elevated" levels of heavy metals in fish and shellfish from Vieques (see Section III). People who regularly eat fish and shellfish may be exposed to these chemicals. The purpose of ATSDR's sampling and analysis activities was to determine whether the muscle tissues from commonly consumed fish and shellfish contain levels of heavy metals and explosives compounds that would adversely affect public health(4). To assist in the activities, ATSDR worked with the US Environmental Protection Agency's Environmental Response Team (EPA/ERT) to collect and analyze fish and shellfish from the coastal waters and near shore land on Vieques.
Fish and shellfish were collected from six locations on Vieques (see Figure 3). The following locations were chosen to represent productive fishing areas surrounding the island (Ecology and Environment 1986 as cited in Navy 2000b):
Species Collected
At each location, field personnel attempted to catch (or purchase, in the case of the fish market) five individuals from the following types of fish targeted for analysis: yellowtail snapper (Ocyurus chrysurus)/mutton or lane snapper (Lutjanus sp.), grouper/red hind/rock hind/coney (Epinephelus sp.), grunt (Haemulon sp.), parrotfish (Scaridae family), and goatfish (Mullidae family). In addition, field personnel attempted to catch or purchase five individuals of queen conch (Strombus gigas) and spiny lobster (Panulirus argus) at each sampling location. These fish and shellfish were determined to be commonly caught and consumed by the residents of Vieques, based on research by Universidad Metropolitana (Caro et al. 2000), discussions with the petitioner and residents of Vieques, information provided in the Vieques Special Commission Report (Government of Puerto Rico 1999 as cited in Navy 2000b), and visits to local fish markets. In addition, to address a specific community concern, ATSDR collected one honeycomb cowfish (Lactophrys polygonia ) from the fish market.
Field personnel planned to collect a sufficient number of individuals of blue land crab (Cardisoma guanhumi) on shore, adjacent to Locations 1, 2, and 6 and fiddler crab (Uca sp.) adjacent to Locations 1 and 2 to meet the tissue mass requirements for five replicates of the desired chemical analyses(5) . For safety reasons, Navy technicians collected these crabs on the LIA and transferred them to field personnel the same day they were collected. Land crabs were determined to be a species eaten by the residents of Vieques, while fiddler crabs are not known to be a species that is eaten.
Table 7 summarizes the species of fish and shellfish that were collected from each sample location. For reference, Appendix E contains pictures of the species collected.
Quality Assurance and Quality Control
The data used in this investigation meets established EPA standards for adequate quality assurance and control measures for sampling procedures, chain-of-custody procedures, laboratory procedures, and data reporting. The analytical methods and detection limits established for this investigation were consistent with the study's objectives and were sufficient to enable a conservative evaluation of health implications. Appendix B contains more details concerning the sampling methods for ATSDR's fish and shellfish investigation.
Organism General Health
All collected organisms were given a brief physical examination. However, the white grunts (H. plumieri) collected at the fish market had already had their gut cavities cleaned prior to sale; therefore, no internal examination was possible. All of the organisms collected from all of the sampling locations appeared to be healthy. Few had any obvious deformities or parasites, with the exception of the following.
Chemical Analysis
Fish and shellfish tissues were analyzed for explosives compounds. No explosives compounds were detected in fish tissues from any sample location. Of the 42 shellfish samples, only fiddler crabs contained an explosives compound(6) (HMX; see Table 5). No explosives compounds were detected in conch, lobster, or land crab samples from any location (see Table 9).
Metals
Fish and shellfish tissues were analyzed for heavy metals. Finding heavy metals in fish and shellfish is not unique to Vieques. Depending on the geology and chemical composition of the area, a variety of metals can be found in varying concentrations (e.g., EPA 2001a). If the levels are too high and pose a health concern, health agencies issue advisories against eating fish or shellfish. Of the heavy metals, mercury is the chemical of concern in the largest number of states (EPA 2000).
Methylmercury
One tissue sample from each of four species (red hind, white grunt, yellowtail snapper, and spiny lobster) collected from the fish market (Location 5) was analyzed for methylmercury. Methylmercury was detected in concentrations of 0.02-0.08 ppm (parts per million) in fish and 0.019 ppm in shellfish. Results are summarized in Tables 8 and 9.
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Are the levels of mercury higher in fish from Vieques?
Because of its persistence in the environment and bioaccumulative property, mercury is the primary contaminant driving fish advisories—almost 75% of all fish advisories are related to mercury contamination (EPA 2002). In general, the levels of mercury measured in fish collected from Vieques were about the same as those from the mainland of Puerto Rico and the Virgin Islands. In Vieques, the average mercury level was 0.12 ppm. Average mercury levels found in the same species of fish from Puerto Rico and the Virgin Islands ranged from 0.07 to 0.70 (Burger et al. 1992). Average mercury levels in seafood species, collected nationwide, ranged from not detected to 1.45 ppm (FDA 2001b). It is also interesting to note that people who eat fish from Vieques would receive about as much mercury as people who eat canned tuna (according to a 1991 FDA survey, the average mercury concentration in canned tuna is 0.17 ppm; Yess 1993 as cited in ATSDR 1999a).
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1 As of May 2003, the former Navy portions of Isla de Vieques are under the control of the U.S. Fish and Wildlife Service.
2 It was not noted in the study by Caro et al. 2000 if the concentrations were reported as wet weight concentrations or dry weight concentrations, ATSDR is assuming they are wet weight concentrations.
3 The National Academy of Science notes that there are limitations to the usefulness of assessing human health concerns from analyses performed on nonedible portions of organisms or on the whole body (EPA 2000).
4 The purpose of ATSDR's sampling and health evaluation is to address any potential chemical contamination in the fish and shellfish; therefore, this public health assessment does not focus on any potential biological conditions (e.g., naturally occurring toxins in fish, diseases, parasites, or bacteria) that may afflict the fish and shellfish of Vieques.
5 Originally, ATSDR planned to collected blue land crabs and fiddler crabs from all six sampling locations. However, due to time constraints and logistical problems encountered during sampling, it was decided to limit the collection to these key locations.
6 Rinsing fiddler crabs of sand and dirt was inadvertently omitted prior to placing them into sample containers. The concentrations detected may not accurately represent the levels of HMX in fiddler crabs, rather the concentrations could be artificially elevated due to the external sand and dirt contamination.
7 Rinsing fiddler crabs of sand and dirt was inadvertently omitted prior to placing them into sample containers. The concentrations detected may not accurately represent the levels of metals in fiddler crabs, rather the concentrations could be artificially elevated due to the external contamination.
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