The objective of this course is to convey an appreciation of the sources, behaviour, fate, and effects of selected toxic compounds which may be present in the environment. Emphasis is on organic compounds, including hydrocarbons, halogenated hydrocarbons and pesticides. The approach will be to examine, for each compound, physical and chemical properties, sources, uses, mechanisms of release into the environment, major environmental pathways and fates (including atmospheric dispersion and deposition), movement in aquatic systems (including volatilization, incorporation into sediments, biodegradation, photolysis, sorption), movement in soils, and bioconcentration. Toxicology and analytical methodology will be described very briefly. Each student will undertake a detailed individual study of a specific toxic compound.