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Human Health and Environmental Toxicology

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Human Health and Environmental Toxicology

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    2. Human Health

    7. Health Issues in Highly Developed Countries Leading causes of death in US: Cardiovascular diseases, cancer, & chronic obstructive pulmonary disease

    8. Health Issues in Developing Nations Malnutrition, unsafe water, and poor sanitation

    9. Diseases

    10. Environmental Pollution & Disease

    11. Persistence Degradation of synthetic pesticides is slow. Many remain in soil / water for years. Sometimes the breakdown products are as toxic as the original chemical

    12. Bioaccumulation

    13. Biomagnification

    14. Biomagnification Example: Effect of DDT on bald eagles

    15. Endocrine Disruptors Chemicals that alter hormone production. Ex: PCBs, dioxins, lead, mercury, DDT Hormones have their affect at low doses. Endocrine disruptors act similarly.

    16. Endocrine Disruptors Example: American alligators and DDT spill

    17. Lake Apopka Alligators Population decline due to “reproductive incompatibility” DDT and other chemicals came from a spill in 1980 Egg mortality rate was also high during the effected period

    18. Determining Health Effects of Environmental Pollution Toxicant – Chemical that induces adverse response at a certain dose. Toxicity of a chemical is assessed by determining its LD50 (dose at which 50% of test subjects die due to exposure)

    19. Determining Health Effects of Environmental Pollution Lethal Dose-50% (LD50)

    20. Determining Health Effects of Environmental Pollution Effective Dose-50% (ED50) – Dose that induces 50% of test subjects to have some type of effect Dose response curve –

    21. Determining Health Effects of Environmental Pollution Children and chemical exposure

    22. Determining Health Effects of Environmental Pollution Identifying Cancer-Causing Substances Carcinogen – Environmental agent known to induce cancer. Chemicals commonly tested with rats but, is the dose equivalent? Can you extrapolate the results to humans?

    23. Health effects of environmental pollution What about mixing chemicals? synergistic mixtures actually magnify the effects you would expect from those chemicals individually antagonistic mixtures reduce the effects you would expect additive mixtures are exactly what you would expect In order to understand the effects of various mixtures, (like cigarette smoke, for example) that EXACT mixture would have to be tested.

    24. Ecotoxicology Dilution paradigm – “the solution to pollution is dilution” Boomerang paradigm – “what you throw away can come back and hurt you”

    25. Decision Making and Uncertainty Risks:

    26. Decision Making and Uncertainty Cost-Benefit Analyses

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