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Coastal and Estuarine Risk Assessment - Chapter 5

Bioavailability, Biotransformation, and Fate of Organic Contaminants in Estuarine Animals - Một thành phần quan trọng của nghiên cứu đánh giá rủi ro sinh thái trong các đại dương và cửa sông bao gồm các đặc tính của sự tiếp xúc của động vật cửa sông để chất gây ô nhiễm. Dữ liệu về sinh khả dụng, sự thu hút, tích tụ, và loại bỏ | 5 Bioavailability Biotransformation and Fate of Organic Contaminants in Estuarine Animals Richard F. Lee CONTENTS 5.1 Introduction 5.2 Bioavailability 5.3 Uptake 5.3.1 Uptake from Water 5.3.2 Uptake from Sediment 5.3.3 Uptake from Food 5.4 Fate of Xenobiotics after Uptake by Estuarine Animals 5.4.1 Biotransformation Metabolism 5.4.1.1 Phase-One Reactions 5.4.1.2 Phase-Two Reactions 5.4.2 Fates and Metabolic Pathways for Xenobiotics and Metabolites within Tissues and Cells 5.4.3 Binding of Xenobiotics to Cellular Macromolecules 5.5 Elimination 5.6 Summary References 5.1 INTRODUCTION An important component of ecological risk assessment studies in oceans and estuaries includes the characterization of the exposure of estuarine animals to contaminants. Data on the bioavailability uptake accumulation and elimination 2002 CRC Press LLC of contaminants by animals are necessary to characterize contaminant exposure.1 Contaminants found in estuarine and marine waters and sediments include aromatic hydrocarbons organometallics organohalogens and pesticides often referred to as organic xenobiotics. The high concentrations of various xenobiotics in aquatic animals from contaminated sites are indicative of the efficient uptake and accumulation of these xenobiotics.2-14 As a result of the presence of these contaminants in tissues many toxicological effects may be manifested including the following growth reproduction and development. The extent of uptake of xenobiotics by an estuarine animal depends on their bioavailability from various matrices including water sediment or food. After entering from one of these matrices via the gill or digestive tract the xenobiotic can be accumulated in the liver fish or hepatopancreas digestive gland annelid crustacean mollusk . Hemolymph or blood functions as an important avenue for transporting xenobiotics and xenobiotic metabolites Figure 5.1 . After entrance into an animal the processes of accumulation biotransformation and elimination .