tailieunhanh - Special Topics

Special Topics I. Selenium Ecotoxicology II. Arsenic in Drinking Water Principles of Environmental Toxicology Instructor: Gregory Möller, . University of Idaho. Examine the chemistry of selenium in inorganic and organic molecules. Understand the role of seleno-amino acids in the expression of selenium toxicity in plant and animal systems. Examine chronic selenium toxicosis (selenosis). Understand the role of selenium in reproductive failure. | Special Topics I. Selenium Ecotoxicology II. Arsenic in Drinking Water Principles of Environmental Toxicology Instructor Gregory Möller . University of Idaho Principles of Environmental Toxicology Learning Objectives Examine the chemistry of selenium in inorganic and organic molecules. Understand the role of seleno-amino acids in the expression of selenium toxicity in plant and animal systems. Examine chronic selenium toxicosis selenosis . Understand the role of selenium in reproductive failure. Principles of Environmental Toxicology Learning Objectives Describe the biogeochemical cycle of selenium. Analyze environmental Se case studies. Examine the regulatory and scientific issues involved in Se risk assessment. Explore the occurrence of Arsenic in drinking water. Describe the US As regulatory changes Describe the clinical pathology of arsenicosis. Examine the arsenic in drinking water public health emergency in Bangladesh. Principles of Environmental Toxicology Environmental Selenium Sulfur analogue. -sulfate selenate. -sulfite selenite. -sulfide selenide. - S 0 Se 0 . - organic compounds. Essential trace element toxic at higher concentrations. Principles of Environmental Toxicology Forms of Selenium Selenides -II Se2- Reducing environments. Forms metal complexes highly immobile Dimethylselenide CH3 2Se Volatilization from soil bacteria and fungi Dimethyldiselenide CH3 2Se2 Volatilization from plants Dimethylselenone CH3 2SeO2 Volatile metabolite Hydrogen selenide H2Se Unstable moist air decomposes to Se0 in water Seleno-amino acids Selenomethionine Se-cysteine Se-methyl-selenocysteine Se-cystathionone Principles of Environmental Toxicology Forms of Selenium 2 Elemental Selenium 0 Se0 Stable reducing environments very slow oxidation and reduction Red Se 0 in a Se reducing bacteria culture. Principles of Environmental Toxicology Forms of Selenium 3 Selenite IV SeO32- Soluble form Trimethylselenomium CH3 3Se Important urinary metabolite Selenous acid .