Marine Mammals and Persistent Ocean Contaminants: Proceedings of the Marine Mammal Commission Workshop Keystone, Colorado, 12-15 October 1998 Edited by Thomas J. O’Shea, Workshop Chairman U.S. Geological Survey Midcontinent Ecological Science Center 4512 McMurry Avenue Fort Collins, Colorado 80525-3400 Randall R. Reeves Okapi Wildlife Associates 27 Chandler Lane Hudson, Quebec J0P 1H0, Canada Alison Kirk Long Marine Mammal Commission 4340 East-West Highway, Room 905 Bethesda, Maryland 20814 April 1999 Marine Mammal Commission 4340 East-West Highway, Room 905 Bethesda, Maryland 20814 e TABLE OF CONTENTS EXECUTIVE SUMMARY ..................................................... iii Section I: BACKGROUND AND OBJECTIVES ..............................1 Introduction ......................................................1 The Marine Mammals ....................................................2 Workshop Objectives .....................................................3 Workshop Agenda and Procedures ..........................................4 Acknowledgments .......................................................5 Section II. PRINCIPAL WORKSHOP FINDINGS AND CONCLUSIONS ......................................................................7 Major .................................................................7 Uncertainties ......................................................................7 Principal ...............................................................9 Section III. WORKING GROUP REPORTS .................................21 Working Group on Immunotoxicology, Pathology, and Disease ............21 Pathology and Disease Subgroup Report ...............................22 Immunotoxicology Subgroup Report .................................26 . Working Group on Endocrinology and Reproduction .....................35 Working Group on Risk Assessment ..................................50 Risk Characterization Subgroup Report ...............................58 Exposure Subgroup Report .........................................60 Measurement of Adverse Effects Subgroup Report ......................66 Surrogate Approaches Subgroup Report ...............................72 Case Study Subgroup Report ........................................78 . Working Group on Future Trends ....................................91 Section IV. EXTENDED ABSTRACTS OF PLENARY PRESENTATIONS .......................................101 Persistent Ocean Contaminants and Marine Mammals: A Retrospective Overview .........................................101 Reproductive and Developmental Effects of Endocrine-disrupting Chemicals on Marine i Mammals ......................................................107 Contaminants and Marine Mammal Immunotoxicology and Pathology ............117 Assessing the Risks to Marine Mammal Populations from Exposure to Contaminants ....................................121 Overview of Federal And International Programs on Contaminants in Marine Mammals ................................129 Overview of Health, Ecological, and Economic Dimensions of Global Change: Tracking Marine Disturbance and Disease ............................132 A Framework for Analyzing the Origins of Contaminants in Marine Mammals ..............................................137 List of Tables: List of Figures: Figure 1. The framework for ecological risk assessment. Figure 2. The interplay of controlled laboratory or captive studies and field correlative studies. Figure 3. Extrapolation in risk assessment: the “weight of evidence.” Figure 4. The integration of field and laboratory studies. Figure 5. Major steroidogenic pathways in mammalian endocrine tissues. Figure 6. The U.S. National Research Council conceptual framework for the process of risk assessment. Figure 7. An analysis of the distribution of contaminant burdens or concentrations in “hosts.” Figure 8. A conceptual framework for analyzing the origin of contaminants in marine mammals. Figure 9. Tissues in the National Marine Mammal Tissue Bank. ii EXECUTIVE SUMMARY The Marine Mammal Commission convened a workshop in Keystone, Colorado, 12–15 October 1998, to review what is known, and what needs to be learned, about the effects of persistent ocean contaminants on marine mammals. Concern about the possible effects of anthropogenic compounds and trace elements in marine mammals has increased in recent years for two main reasons. The first is that disease outbreaks, involving marine mammals with high concentrations of organochlorines in tissues, appear to have occurred with increasing frequency. The second is that experimental and other evidence has shown that certain contaminants often found in the tissues of marine mammals have deleterious effects on reproduction and the immune system. Prompted by these and other contaminant-related concerns, the Marine Mammal Commission, with the co-sponsorship of the U.S. Geological Survey, the National Marine Fisheries Service, the Environmental Protection Agency, and the National Fish and Wildlife Foundation, organized this international workshop, involving scientists from seven countries. Expertise of workshop participants included environmental toxicology, environmental chemistry, marine mammal health and husbandry, pathology and disease, physiology, immunotoxicology, marine mammal population dynamics and ecology, experimental design, environmental risk assessment, and wildlife epidemiology. The workshop objectives were to (1) review and summarize the state of knowledge about the types and levels of potentially harmful persistent contaminants found in marine mammals, and about the known and potential effects of these substances on marine mammal health and population dynamics; (2) identify and rank in importance the critical uncertainties concerning the presence, levels, sources, fates, and effects of organochlorines, toxic elements, and other persistent contaminants on marine mammals; (3) outline research and monitoring programs needed to resolve the critical uncertainties as quickly as possible; and (4) assess how ongoing and planned research and monitoring programs should be restructured or expanded. Much of the focus of the workshop was on the persistent ocean contaminants classified as organochlorines. These include many compounds that originated as pesticides or industrial chemicals. Although some countries no longer use or produce most of these compounds, they continue to be manufactured and used in many parts of the world, and they are redistributed to the global marine ecosystem by a variety of transport mechanisms. Marine mammals, many of which exist at the top of complex ocean food webs, continue to be sinks for organochlorines. Only limited consideration was given at the workshop to potentially toxic trace elements and other persistent substances in the marine environment. This was primarily because there is much less evidence suggesting direct harm to marine mammals from these substances. It was acknowledged that marine mammals may also be regularly exposed to other contaminants, such as non-persistent polyaromatic hydrocarbons from petroleum and industrial sources, but these contaminants were not a focal subject of consideration. The workshop consisted of a series of plenary addresses, each followed by a panel discussion, and deliberations and report preparation by four working groups. These working groups were v WORKSHOP ON MARINE MAMMALS AND PERSISTENT OCEAN CONTAMINANTS organized to address priority concerns in the following topic areas: immunotoxicology, pathology, and disease; endocrinology and reproduction; risk assessment; and likely future trends. The workshop report includes a summary of priority uncertainties and a list of 20 principal conclusions and recommendations derived from the working group reports (Section II), detailed reports prepared by the working groups (Section III), extended abstracts of the plenary presentations (Section IV), and a small series of appendices (Section V). Reproductive problems observed during the 1960s and 1970s in female California sea lions off southern California, female harbor seals in the Wadden Sea, and female ringed and gray seals in the Baltic Sea were associated with high body burdens of organochlorines, particularly PCBs and metabolites of DDT. A study of captive harbor seals in The Netherlands, published in 1986, demonstrated an association between impaired reproduction and exposure to organochlorines in the seals’ diet. Other studies in the 1980s and 1990s suggested that organochlorines affect endocrine and immune function in some marine mammals. Beluga whales downstream from heavily polluted portions of the St. Lawrence River–Great Lakes watershed and seals in the Baltic Sea have various lesions strongly suggestive of contaminant effects. Die-offs of seals and small cetaceans in Europe and North America from disease (primarily morbilliviruses) during the late 1980s and 1990s evoked much public concern about the role of contaminants. Although investigations of the links between disease outbreaks and contaminants based on studies of carcasses were inconclusive, they led to experimental studies with harbor seals in Europe showing organochlorine-linked effects on immunocompetence. Additional studies reviewed at this workshop added weight to the argument that organochlorines have immunosuppressive effects on marine mammals. The workshop concluded that there is good reason to be concerned that survival and reproduction in certain marine mammal populations may have been affected, and are being affected, by persistent