Coastal and Estuarine Risk Assessment - Chapter 9

The Use of Toxicity Reference Values (TRVs) to Assess the Risks That Persistent Organochlorines Pose to Marine Mammals - Động vật có vú biển được biết đến tích tụ nồng độ tương đối cao liên tục organochlorine chất gây ô nhiễm (POCs). Các cửa hàng của chất gây ô nhiễm có tiềm năng hành động như là một nguồn tiếp tục tiếp xúc nâng lên những sinh vật này. Mặc dù một số lượng đáng kể được biết về các nồng độ của POCs các loài động vật có vú sống ở biển và về các quá trình dẫn đến sự tích tụ của họ,. | 9 The Use of Toxicity Reference Values TRVs to Assess the Risks That Persistent Organochlorines Pose to Marine Mammals Paul D. Jones Kurunthachalam Kannan Alan L. Blankenship and John P. Giesy CONTENTS Overview Introduction Problem Formulation Exposure Assessment Exposure Assessment Methods Estimating Exposure through Modeling Measuring Internal Dose Using Tissue Residues Effects Assessment Adverse Effects in Marine Mammals Immunotoxicological Studies in the Harbor Seal Toxicological Studies in Cetaceans Exposure Studies in Mustelids Toxicity Reference Values Toxicity Threshold Evaluation Uncertainties in TRV Determination Risk Characterization Risk Assessment Based on New Zealand Data Conclusions Acknowledgments References 2002 CRC Press LLC OVERVIEW Marine mammals are known to accumulate relatively high concentrations of persistent organochlorine contaminants POCs . These stores of contaminants have the potential to act as a continuing source of elevated exposure to these organisms. Although a considerable amount is known about the concentrations of POCs in marine mammals and about the processes that lead to their accumulation little is known about the potential these contaminants have to cause adverse effects in exposed animals. Although several anecdotal studies have measured relatively high POC concentrations in marine mammals associated with mass mortality events in all cases it has been difficult to demonstrate a cause-effect 2 Similarly several semifield studies have been conducted by feeding naturally contaminated fish to captive animals and assessing adverse 4 It is also difficult to attribute effects of organochlo-rines in these studies due to small sample sizes and the presence of co-contaminants in the food source used for feeding. To determine possible adverse effect levels in marine mammals we previously compiled a number of the