V. EVALUATION OF FISH AND SHELLFISH FROM VIEQUES
ATSDR's PHAs are driven by exposure or contact. Chemicals released into the environment have the potential to cause harmful health effects. Nevertheless, a release does not always result in exposure. People can only be exposed to a chemical if they come in contact with that chemical. If no one comes into contact with a chemical, then no exposure occurs, thus no health effects could occur. Often the general public does not have access to the area where the environmental release occurs; however, it is important to determine whether the chemicals are moving through the environment to locations where people could come into contact with them.
The means in which a chemical moves through the environment, and how people contact the chemical, defines an exposure pathway. ATSDR identifies and evaluates exposure pathways by considering how people might come into contact with a chemical. In this public health assessment, ATSDR is evaluating exposures from eating potentially contaminated fish and shellfish from the coastal waters and near shore land on Vieques.
If someone is exposed, will they get sick?
Exposure does not always result in harmful health effects. The type and severity of health effects that occur in an individual as the result of contact with a chemical depend on the exposure concentration (how much), the frequency and duration of exposure (how long), and the multiplicity of exposure (combination of chemicals). Once exposure occurs, characteristics such as age, sex, nutritional status, genetics, lifestyle, and health status of the exposed individual influence how that individual absorbs, distributes, metabolizes, and excretes the chemical. Taken together, these factors and characteristics determine the health effects that can occur as a result of exposure to a chemical in the environment.
Considerable uncertainty exists regarding the true level of exposure to environmental contamination. To account for that uncertainty and to protect public health, ATSDR scientists typically use high-end, worst-case exposure level estimates to determine whether harmful health effects are possible. ATSDR used the following conservative approaches throughout this public health evaluation:
Therefore, the estimated exposure levels are much higher than the levels to which people are really exposed. If the exposure levels indicate harmful health effects are possible, a more detailed review of exposure, combined with scientific information from the toxicologic and epidemiologic literature about the health effects from exposure to hazardous substances, is performed.
What exposure situations were evaluated in this PHA?
ATSDR focused this health evaluation on the edible samples that ATSDR worked with EPA/ERT to collect in July 2001 from six locations on and around Vieques, including five families of commonly caught and consumed fish and three species of shellfish (see Table 7). Fiddler crabs were not included in the health evaluation because it is ATSDR's understanding that fiddler crabs are not a species that people eat. Each of the other species was considered to equally represent fish or shellfish that are directly consumed by the residents of Vieques.
ATSDR evaluated several different consumption scenarios depending on a person's fish and shellfish intake. According to the survey conducted by Universidad Metropolitana, almost half the residents of Vieques eat fish one or two times a week. However, about 16% responded that they eat fish five or more times a week (Caro et al. 2000). Therefore, to account for the variability in dietary habits, ATSDR estimated exposure from eating fish or shellfish 7 days a week, 5 days a week, 4 days a week, 2 days a week, and 1 day a week. The scenario of eating fish or shellfish 7 days a week was evaluated first. If this intake level revealed a potential health hazard, ATSDR determined what a safe consumption level would be.
Individual metals in individual species varied from location to location (ATSDR 2002). Thus, it is possible that if someone were to regularly eat fish or shellfish caught from a single location rather than from a variety of locations, his/her metal intake level could be different than the average (either higher or lower than the average). Therefore, in addition to determining an overall exposure for people who eat fish and shellfish from a variety of locations surrounding Vieques, ATSDR also examined whether eating fish or shellfish from any specific location would cause people to experience adverse health effects.
Universidad Metropolitana questioned the residents of Vieques about the types of fish they eat and reported that yellowtail snapper was the most commonly consumed species of fish (Caro et al. 2000). Through talking with several Vieques fishermen and residents, including the petitioner, ATSDR confirmed that snapper were most commonly sought after, caught, and consumed than any other species of fish. Therefore, ATSDR also considered a specific situation where people ate snapper on a daily basis.
For reference, Appendix A is a glossary of environmental and health terms and Appendix D describes in greater detail the methods and assumptions ATSDR used to estimate human exposure doses and determine health effects.
Is it safe to eat fish and shellfish from Vieques?
Yes, the fish and shellfish from Vieques are safe to eat. Even though several metals were detected in some of the fish and shellfish, the concentrations that were present were too low to be of health concern in virtually all exposure situations evaluated. Appendix D describes in greater detail how ATSDR reached this conclusion.
Is it safe to eat fish and shellfish every day?
Yes, it is safe to eat a variety of fish and shellfish from Vieques on a daily basis. ATSDR evaluated this specific scenario in detail in Appendix D and determined that eating a variety of fish and shellfish would not result in adverse health effects or an increase in the risk of developing cancer.
Arsenic levels in lobsters
| Arsenic levels in fish and shellfish are usually about 4-5 ppm, but may be as high as 170 ppm (Bennett 1986; NAS 1977b; Schroeder and Balassa 1966 as cited in ATSDR 2000a). According to a 1978 National Marine Fisheries Service survey, mean arsenic levels in lobsters range from 10-20 ppm (FDA 1993). However, FDA notes that in some cases arsenic levels in lobsters may exceed 100 ppm (Benson and Summons 1981; Bohn 1975; LeBlanc and Jackson 1973 as cited in FDA 1993). For comparison, arsenic levels in lobsters from Vieques ranged from 23.4-48.3 ppm and averaged 32.9 ppm. |
ATSDR concludes that lobsters from Vieques are safe to eat and only under highly unlikely, hypothetical scenarios with several levels of conservatism built into the evaluation might the arsenic levels in lobsters be a problem for people eating more than two meals of lobster a week for a lifetime.
Is it safe to eat fish and shellfish from any location?
Yes, it is safe to eat fish and shellfish from all of the areas that ATSDR sampled. Despite the fact that some metals were detected in higher concentrations at different locations, none were so much higher that ATSDR would expect to see adverse health effects in people who may solely eat fish or shellfish from a single location (e.g., only from the fish market or only from areas around the LIA). In other words, even though there are differences in fish and shellfish body burdens between locations, these differences are too small to have an impact on public health.
Is it safe to eat the most commonly caught and consumed fish every day?
ATSDR determined that it is safe to eat snapper, reportedly the most desirable and most commonly consumed species, on a daily basis. In Appendix D, under the section titled Special Case: Snapper, ATSDR describes in greater detail how this conclusion was reached.
An integral part of the public health assessment process is addressing community concerns related to environmental health. ATSDR has been working with, and will continue to work with, the community to define specific health issues of concern. On multiple trips to the island, ATSDR has met with a variety of individuals and organizations, including local officials, physicians, nurses, pharmacists, leaders of women's groups, school educators, fishermen, and business people. ATSDR has also met with individual families. Meeting with a broad spectrum of community members is critical to determine health issues of concern and to assess the environmental health issues on Vieques.
General issues of health concern related to exposure to the soil, groundwater and public drinking water on Vieques were addressed in previously released PHAs (ATSDR 2001a, 2003). Another PHA will focus on addressing potential health issues resulting from air releases from the LIA. In addition, an expert review panel discussed the issue of whether an association existed between place of residence and heart disease among fishermen (ATSDR and PSM 2001). This section of the PHA addresses additional community concerns related to the fish and shellfish evaluation.
In November 1999, lawyers for the Puerto Rican Government contracted the University of Georgia to examine the health of the coral reefs. During their investigation they reported seeing two sunken vessels in Bahía Salina del Sur (south of the LIA) that contained hundreds of 55-gallon drums of unknown content. The community expressed concern that unknown substances could be leaking from these drums, contaminating the marine biota, and affecting the health of island residents.
The wreckage is actually the scuttled remains of the former USS Killen (Killen), a World War II destroyer which had been used as a target vessel. To address the concern, ATSDR sampled and analyzed fish and shellfish at this site in July 2001, as sample Location 2. Despite the common occurrence of unexploded ordnance, the site was home to a diverse population of apparently healthy fish and small head corals, and were surrounded by a large halo (the halo is a typical feature of reefs and underwater structures that is caused by grazing organisms leaving the shelter of the reef at night to feed on the surrounding seagrass beds) and a healthy turtle grass bed (see Appendix C for more details). In addition, ATSDR's evaluation determined that the fish and shellfish collected from Location 2 do not contain levels of metals or explosives compounds that would adversely affect the health of someone eating fish and shellfish from this area (see the Public Health Evaluation (Section VB) and Appendix D for more details).
The Navy and the Puerto Rico Department of Natural and Environmental Resources conducted personnel interviews and reviewed the document history of the sunken vessel. Personnel noted that despite numerous fly overs, no one observed any loss of residual material, oil slicks, or plumes coming from the wrecks (Navy 2000a). The investigative committee hypothesized that the 55-gallon drums were filled with air and placed on board to enhance buoyancy to keep the vessel afloat as long as possible (Navy 2000a). A second theory is that, in addition to being used for added target buoyancy, the 55-gallon drums were filled with sand or seawater and used as ballast to redistribute the weight of the vessel (i.e., add stabilization) after several alterations were made to remove much of the superstructure, armament, and heavy engineering components (Geo-Marine 2002).
In 2001, the Navy conducted a site investigation and characterized the biological organisms to assess the health of the marine species on and around the vessel and to assess potential impacts on the surrounding biota (Geo-Marine 2002). The overall conclusion was that the sunken vessel and its contents are not having a negative effect on the coral reef ecosystem, rather they are acting as a productive artificial reef habitat. The Navy will provide these results to EPA, who along with the Puerto Rico Environmental Quality Board (PREQB), will determine if further analysis is warranted.
Concern has been expressed that because the Killen was a target ship during Operation HARDTACK, it could be contaminating the waters and biota around its resting place with radiation. Operation HARDTACK consisted of underwater nuclear tests in the Pacific in 1958. ATSDR received and reviewed information from the Navy regarding Operation HARDTACK and the involvement of the Killen. During the tests, the Killen was under constant water wash before and after the blasts to remove as much of the radioactivity as possible. A few days after each test, crews went on board, surveyed the ship, and manually decontaminated those areas needing additional treatment. There is no indication that sandblasting was used as the method of decontamination. After the nuclear tests, the Killen was towed to several locations including Hawaii, the Panama Canal Zone, and Norfolk, Virginia. From 1963 until 1975 the vessel was docked at Roosevelt Roads when not in use as a target vessel. The Killen was finally scuttled in 1975.
Radiation measurements collected in 1975 showed that the radiation intensity aboard ship was less than 0.75 microroentgen per hour (R/h) (SAIC 2002) . Additional radiation readings were collected in March 2002. These readings were 0.33 R/h above background (SAIC 2002). For comparison, typical background is approximately 10 to 17 R/h, varying with location. Background levels of radiation result from several naturally-occurring sources, such as cosmic radiation from space and terrestrial radiation from radioactive materials in the ground.
An ATSDR health physicist also spoke with a Navy radiation scientist on this issue. As with typical nuclear tests, the predominate radioisotopes contributing to the radiation exposures was cesium 137 and strontium 90. Since the forms of cesium and strontium are reduced by half every 30 years, one can estimate that without any intervention of weather or man, the amount of these radioisotopes would be about 25% of the initial amount present on the Killen. This is seen in the data as the radiation readings taken in 2002 were more than 2 million times lower than the readings taken immediately after the tests.
Based on these observations, the radiation levels associated with the Killen are indistinguishable from the radiation associated with background levels naturally found in the environment (e.g., from cosmic and terrestrial sources) and do not pose any public health hazard to the residents of Vieques.
Concern was expressed regarding possible metals contamination of marine biota and of SCUBA divers visiting the remains of the Killen. Although ATSDR does not have specific water chemistry data from the vicinity of the Killen, there is no likely harmful exposure to chemicals that could result from SCUBA diving around the vessel. It should be pointed out that any sunken vessel can contain physical hazards that need to be considered in any diving activity. Also, because the area surrounding the Killen, and the Killen itself, have been targets in bombing and firing training, there could be hazard from unexploded ordnance.
There is a large body of information with which to address the concern that a sunken vessel promotes chemical contamination to the environment. Ships and other manmade objects such as defunct oil rigs, automobiles, and rail cars are frequently sought by natural resource agencies and private environmental organizations world-wide, to be used as artificial reef. Such structures form desirable habitat for marine biota and are common sites of recreational fishing and diving activities throughout the world. Although ATSDR does not endorse or recommend unauthorized diving in these waters, there is nothing unique in the construction of the former Killen that would suggest a human health hazard from exposure to metals by divers or marine biota. The following information on the environmental value of artificial reefs, including sunken vessels, was collected from publicly available Web sites.
"Alabama has the largest artificial reef program in the United States at the present time. The natural bottom offshore of Alabama is predominately flat sand bottom. This bottom type attracts few fish that are either commercially or recreationally valuable. However, it has long been known that if vertical relief is created on this bottom, many reef fish such as snappers and groupers will be attracted. In fact artificial reefs can be created that over time will appear as natural reefs with similar communities of encrusting organisms and bait fish. As various encrusting organisms such as corals and sponges cover the artificial reef material, small animals take up residence. As these small animals become abundant larger animals are attracted and feed upon these. Yet larger fish are attracted to these and so on until a complete reef food web is created. At that point the artificial reef functions as a natural reef. Alabama's artificial reef building program started in 1953 when the Orange Beach Charter Boat Association asked for the authority to place 250 car bodies off Baldwin County, Alabama. This proved to be very successful and in the years since, many different types of materials have been placed offshore of Alabama. These have included additional car bodies, culverts, bridge rubble, barges, boats and planes" (Alabama Dept of Conservation and Natural Resources, Marine Resources Division 2003).
"Artificial reefs rise like oases in the desert -- dotting the vast expanses of mud and sand covering the floor of the Gulf of Mexico. These underwater havens provide hard surfaces required for attachment by invertebrates such as barnacles, corals, sponges, clams, bryozoans and hydroids. These reefs are particularly important since the habitat is limited for many of them. These organisms are the beginnings of an interactive food web that supports a host of reef fish species. By providing food and shelter, artificial reefs can enhance overfished populations of resident reef fish like snapper and grouper. Transient species like mackerel, shark and billfish can also benefit by feeding on the resident fish" (Texas Parks and Wildlife Commission 2003).
"Since 1984, the bureau has been involved in an intensive program of artificial reef construction and biological monitoring. The purpose is to create a network of artificial reefs in the ocean waters along the New Jersey coast to provide a hard substrate for fish, shellfish and crustaceans, fishing grounds for anglers, and underwater structures for scuba divers. Artificial reefs are constructed by intentionally placing dense materials, such as old ships and barges, concrete ballasted tire units, concrete and steel demolition debris and dredge rock on the sea floor within designated reef sites. At present, the division holds permits for 14 artificial reef sites encompassing a total of 25 square miles of sea floor" (New Jersey Division of Fish and Wildlife 2003).
Artificial Reefs of the Keys is a non-profit group in Key West, Florida, working to bring the de-commissioned ex-USAFS Gen. Hoyt S. Vandenberg to Florida waters to become an artificial reef. "At over 520 feet and 13,000 tons, this will be the largest ship ever intentionally sunk for this purpose. This ship will become a world-class diving destination, but it will also offer many other benefits to the environment and to education and research" (Artificial Reefs of the Keys 2003).
While on Vieques, ATSDR met with the petitioner, who at that time, specifically requested ATSDR to collect and analyze boxfish (family Ostraciidae; e.g., cowfish and trunkfish) from the fish market. At the request of ATSDR, the petitioner had compiled a list of fish caught and eaten on Vieques and reported that Chapín (boxfish) are the preferred fish to use as filling in pastelillos. Realizing that the results and conclusions would be limited, ATSDR agreed to collect a representative sample. A cowfish (honeycomb cowfish, Lactophrys polygonia) was purchased from the fish market for analysis. The results are presented in Table 10.
Of the fish sampled by ATSDR, the cowfish contained the highest concentrations of arsenic (29.3 ppm) and selenium (2.5 ppm). It should be noted that it is not unusual for different samples of the same species to contain varying chemical concentrations; therefore, other cowfish samples may contain higher or lower levels of these chemicals. However, consuming cowfish with the levels detected would not be expected to result in harmful health effects (see Appendix D for more details on the methods and assumptions ATSDR used to estimate human exposure doses and determine health effects).
Community members can direct additional health concerns to:
Program Evaluation, Records, and Information Services Branch
ATSDR, Division of Health Assessment and Consultation
Attn: Isla de Vieques, Puerto Rico
1600 Clifton Road, NE (E-60)
Atlanta, Georgia 30333
Community members can also telephone the ATSDR regional representatives in New York, New York, at (212) 637-4307 or call the toll-free telephone number, 1-888-42-ATSDR.
VII. CHILD HEALTH CONSIDERATIONS
ATSDR recognizes that infants and children can be more sensitive to contamination of their food than adults because children are smaller, therefore childhood exposure results in higher doses of chemical exposure per body weight. Because children can sustain permanent damage if these factors lead to toxic exposure during critical growth stages, ATSDR as part of its public health assessment process is committed to evaluating their special interests at sites such as Vieques.
ATSDR specifically evaluated the exposure to children and determined that they can safely eat fish and shellfish from Vieques.
Through its sampling program and public health evaluation, ATSDR has drawn the following conclusions regarding the fish and shellfish of Vieques:
The Public Health Action Plan for Vieques contains a description of actions taken and those to be taken by ATSDR, the Navy, EPA, PREQB, and the Puerto Rico Department of Health (PRDOH). The purpose of the Public Health Action Plan is to ensure that this PHA not only identifies potential public health hazards, but also provides a plan of action to mitigate and prevent harmful human health effects that may be resulting from exposure to hazardous substances in the environment. The public health actions that are completed, ongoing, and recommended are as follows:
Jeffrey Kellam, M.S.
Geologist
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
Gary Campbell, Ph.D.
Environmental Health Scientist, Section Chief
Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
Michelle Arbogast, M.S.
Environmental Scientist
Eastern Research Group
Field Sampling Team
Gregory Zarus, M.S.
Atmospheric Scientist
Exposure Investigations and Consultation Branch
Division of Health Assessment and Consultation
Alan Humphrey
Environmental Scientist
US Environmental Protection Agency Environmental Response Team
Daniel Cooke, M.S.
Marine Scientist
Lockheed Martin
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