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TOXICOLOGY

OCCUPATIONAL TOXICOLOGY. Attempt to define levels of chemical that are safe and do not produce adverse symptoms or disease-permissible levels can be defined for dusts, fumes particles, vapours, gases and etc.Exposure to some chemicals may need to be close to or equal to zero. TOXICOLOGY. A poison ca

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TOXICOLOGY

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    1. TOXICOLOGY Toxicology is essentially a study of poisons and is concerned with :- The chemical nature of poisons The interaction of poisons with biological systems Safety evaluation or toxicity testing of potentially toxic materials(substances)

    2. OCCUPATIONAL TOXICOLOGY Attempt to define levels of chemical that are safe and do not produce adverse symptoms or disease-permissible levels can be defined for dusts, fumes particles, vapours, gases and etc.Exposure to some chemicals may need to be close to or equal to zero

    3. TOXICOLOGY A poison can be defined as :- Any agent capable of producing a deleterious response in a biological system that seriously impairs function or produces death.

    4. TOXICOLOGY Almost all substances at a sufficient dose can be toxic :- Salt Water Alcohol paracetamol

    5. POISONS Some substances act as poisons in moderate to large amounts Alcohol Sodium chloride Most drugs used in clinical practice example : aspirin, paracetamol and etc.

    6. POISONS Some substances act as poisons in small amounts Cyanide Carbon monoxide Dioxin Botulinum toxin

    7. Acute Toxicity Acute toxic effects are those appearing relatively rapidly as a result of exposure to a relatively large quantity of a poison normally as a result of single dose Potassium cyanide,KCN 200mg in man is a lethal dose :- Immediate collapse Irregular breathing death

    8. Chronic Toxicity This results from frequent or rarely infrequent exposure to low levels of poison over a long period of time, often years Mantakassa epidemic, Mozambique early 1980s after long drought Found to be due to chronic cyanide poisoning from bitter cassava initially thought to be viral disease

    9. Other Examples of Chronic Toxicity Exposure to asbestos fibres Lung cancer mesothelioma Asbestosis Lungs are scarred and lose elasticity and breathing is difficult

    10. Toxicity from More Than One Substance Additive effects Combined effects of two compound is approx. the sum of the individual effects. Synergistic effects The total response is much greater than the sum Alcohol with some drugs and solvents Antagonism An effect when one substance blocks the action of another Eg. An antidote

    11. Factors Influencing Toxicity Dose Health Age Adaptation

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