Tier 2 Fish Toxicity Study
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Tier 2 Fish Toxicity Study Chemical Contaminants in Fish and Shellfish and Recommended Consumption Limits for Territory of American Samoa December 2005 Prepared by: Peter J. Peshut, MSa Barbara A. Brooks, PhDb aTechnical Programs Manager, American Samoa Environmental Protection Agency, Pago Pago bSenior Toxicologist, Hazards Evaluation and Emergency Response, Hawaii Department of Health, Honolulu, USA EXECUTIVE SUMMARY This report presents results from a study for selected contaminants in fish and shellfish collected from the United States Territory of American Samoa, located in the tropical South Pacific. This study was conducted at the Tier 2-level in accordance with US EPA protocols, and follows previously completed Tier 1-level screening studies for the Territory. Data collected were used to recommend consumption limits for fish and shellfish that contain elevated concentrations of inorganic arsenic (As(i)), lead (Pb), mercury (Hg), and polychlorinated biphenyls (PCBs). Overall, this study suggests that coastal reefs of American Samoa are generally clean of the contaminants studied, and that coastal reef biota do not accumulate significant levels of contaminants to limit consumption of seafoods or justify fish advisories. The results of this work confirm and expand upon the previous findings for Pago Pago Inner Harbor, and indicate that As(i), Hg, and PCBs are present at high enough concentrations in the biota to justify a general fish advisory for the Inner Harbor. To a lesser extent Pb was found at elevated levels in Inner Harbor biota, but primarily in shellfish. Pb is not considered a significant determining factor for a fish advisory, but is considered in the overall toxicity assessment for the Inner Harbor. It is recommended that people avoid all fish and shellfish from Pago Pago Inner Harbor due to As(i), Hg, and PCBs. For many of the species collected, contaminants were present in high enough concentrations to restrict fish and shellfish consumption to ≤8 meals per month. The current fish advisory for Pago Pago Harbor should be updated based on this study, and should be re-issued. The role of Risk Manager is incumbent on ASEPA, and this agency should assume primary responsibility for the advisory. Mercury levels in fish and shellfish from Onesosopo were elevated and it is recommended that this location should be studied more thoroughly to determine extent and magnitude of contamination. It is known that Onesosopo Park is constructed on the site of a former uncontrolled municipal dump, and ASEPA water quality data and sediment data for this area indicate possible leachate contamination of the surrounding environment. Arsenic levels were found to be elevated in most biota studied. Consistently elevated levels of arsenic among coastal locations suggest a natural background source, possibly the volcanic parent material of the island. Higher arsenic in Pago Pago Inner Harbor biota compared to biota of coastal locations may be a function of terrigenous sediment input and accumulation. i ACKNOWLEDGMENTS The authors express their appreciation to the many dedicated and qualified individuals who assisted with this work. The late ASEPA Director, Muaavatele Togipa Tausaga, mobilized resources and maintained a clear vision of the overall importance of environmental research in American Samoa. Edna Buchan and her fine staff from the ASEPA Water Program provided field, laboratory, and logistical support. The irrepressible Louie "the fish" DeNolfo tirelessly pursued his finned namesakes for collections, and never ceased to entertain with his inimitable troubadour style. Sasauli Satele contributed her marine science expertise and her local knowledge of Tutuila natural history, and as Louie's wife, kept Louie on course, above and below the waterline. Peter Craig of the National Park Service was a staunch supporter, a persistent reminder, and provided beneficial comments. And fa'afetai tele lava to Carl Goldstein, American Samoa Program Manager, US EPA Region IX, San Francisco, for whom this work was a long time coming. His patience, though it reflects well on his character, could hardly have been withheld. Given all the other work he required of us during this project time frame it's a wonder we got this done when we did. ii TABLE OF CONTENTS Executive summary.......................................................................................................................i Acknowledgments........................................................................................................................ii 1.0 Introduction......................................................................................................................1 2.0 Data Collection.................................................................................................................4 2.1 Collection of Fish and Shellfish...........................................................................4 2.2 Analytical Methods for Fish and Shellfish Specimens........................................5 3.0 Evaluation of Analytical Results......................................................................................6 4.0 Results..............................................................................................................................7 4.1 Inorganic Arsenic.................................................................................................8 4.2 Mercury................................................................................................................8 4.3 Lead......................................................................................................................9 4.4 Polychlorinated Biphenyls...................................................................................9 5.0 Toxicity Assessment........................................................................................................9 5.1 Inorganic Arsenic.................................................................................................9 5.2 Mercury..............................................................................................................10 5.3 Lead....................................................................................................................11 5.4 Polychlorinated Biphenyls.................................................................................11 6.0 Calculations of Risk-Based Consumption Limits..........................................................12 7.0 Uncertainty Analysis......................................................................................................14 8.0 Discussion......................................................................................................................15 8.1 General...............................................................................................................15 8.2 Inorganic Arsenic...............................................................................................17 8.3 Mercury..............................................................................................................17 8.4 Lead....................................................................................................................18 8.5 Polychlorinated Biphenyls.................................................................................18 9.0 Recommendations..........................................................................................................18 10.0 References......................................................................................................................21 TABLES FIGURES APPENDIX – DATA SET iii 1.0 INTRODUCTION This report presents results from a study for selected contaminants in fish and shellfish collected from the United States Territory of American Samoa, located in the tropical South Pacific (Lat. 14o 30' south, Long. 170o 40' west). This study was conducted at the Tier 2-level in accordance with US EPA protocols, and follows previously completed Tier 1-level screening studies. Data collected were used to recommend consumption limits for fish and shellfish that contain elevated concentrations of inorganic arsenic (As(i)), lead (Pb), mercury (Hg), and polychlorinated biphenyls (PCBs). Specific recommendations are provided for consumption of fish and shellfish species analyzed, as shown in the tables. General recommendations for local seafood consumption in American Samoa are also provided. Recommendations are offered as part of the Risk Communication and Risk Management responsibilities incumbent on the American Samoa EPA. Consumption rates of locally caught fish and shellfish can be considered moderate to low among the indigenous and general population of American Samoa. Subsistence fishing and subsistence livelihoods are virtually non-existent in the Territory. The commercial economy of the Territory is well developed compared with neighboring Small Island Developing States, and there are a wide variety of foods available to American Samoans that are common to developed countries. These foods are primarily imported from the United States, Australia, New Zealand, and Asia. Substantial funding allocations from the United States and a range of US-based social welfare programs enable the indigenous population to take part in the cash economy, which promotes the purchase of imported foodstuffs. Chicken, pork, and beef are the major protein sources in the typical American Samoa diet. There is a small local commercial fishing fleet that