CHAPTER I: ECOLOGICAL SYSTEMS AND POLLUTION 1. Introduction.2. Definition and classification of pollutants.3. Bioaccumulators and biomagnification4. Mixtures of polluting compounds.5. Lethal and sublethal effects6. Environmental factors that affect toxicityCHAPTER II: FOOD CHEMICAL CONTAMINATION. Introduction: 1.1 Background.1.2 Biogeochemistry of metals.2. Factors that influence the toxicity of heavy metals. Dietary intake of trace metals.3.1. Ways of incorporation into food.3.2. Toxicological effects.4. Intake estimates. Total Diet Studies.4.1 Toxicological reference values.4.2. Determination of intakes of contaminants in the diet.5. Chemical food safety group.5.1. Surveillance and control areas.CHATER III: METALS TRAIL IN FOODS1. Cadmium.1.1. Dietary cadmium intake.1.2 Toxicity of cadmium.1.3 Treatment of cadmium.2. Lead.2.1. Dietary lead intake.2.2 Lead toxicity.2.3 Lead treatment.3. Mercury.3.1 Mercury intake in the diet.3.2 Toxicity of mercury.3.3 Mercury treatment.4. Arsenic.4.1 Arsenic intake in the diet.4.2 Arsenic toxicity.4.3 Treatment of arsenic.5. Other metals trace contaminants.6. Measures to reduce contamination. Practical sessions: - Preparation and digestion of food samples. - Description and development of the technique of atomic absorption with generation of hydrides. - Description and development of the technique of speciation with fluorescence.