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Human Health and Environmental Toxicology. Human Health Overall human health best assessed by: 1) Life expectancy (years) 2) Infant mortality (# deaths.

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Presentation on theme: "Human Health and Environmental Toxicology. Human Health Overall human health best assessed by: 1) Life expectancy (years) 2) Infant mortality (# deaths."— Presentation transcript:

1 Human Health and Environmental Toxicology

2 Human Health Overall human health best assessed by: 1) Life expectancy (years) 2) Infant mortality (# deaths up to age one per 1,000 live births)

3 Life Expectancy / Infant Mortality Selected countries, 2004 data Life Expectancy (years) Infant Mortality (# deaths up to age one per 1,000 live births) Japan Source: U.S. Census Bureau, International Database Switzerland Sweden Mozambique Zimbabwe Angola

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

5 Health Issues in Developing Nations Malnutrition, unsafe water, and poor sanitation Leads to... Numerous infectious diseases Compounded by poor healthcare, leads to... Lowered life expectancy

6 Emerging v. Reemerging Diseases Emerging – Not previously observed within humans: AIDS, Lyme disease, West Nile virus Reemerging – Existed previously, becoming more common again: Tuberculosis, Yellow fever, Malaria

7 Determining Health Effects of Environmental Pollution Children and chemical exposure

8 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?

9 Determining Health Effects of Environmental Pollution Chemical Mixtures Most studies examine effect of single chemical exposure. What happens when exposed to multiple chemicals? Additive effect? Synergistic effect? Antagonistic effect?

10 Decision Making and Uncertainty Risk assessment: Low High

11 Representative Cellular Targets for Toxic Action 11

12 Three Stages in Carcinogenesis StageNormal cellCarcinogenic agent Initiation Genotoxic initiator Co-carcinogen Initiated cell Promotion Promoter Immunosuppressor Cancer Hormones Dietary compounds Other ProgressionInvasion Metastasis {{{{ {

13 Metabolic Activation of Benzo(a)pyrene

14 2,3,7,8-Tetrachlorodibenzo(p)dioxin

15 Lock and Key Model for Toxic Action Disrupt normal steroid action and may influence the development of endometriosis. A by-product of manufacture and combustion of chlorinated phenols and is considered by some to be one of the most toxic substances ever released into the environment.

16 Toxicological/Ecological Relevance and Time Scale of Toxic Response for Levels of Biological Organization (McGarthy and Shugart, 1989) 16

17 Idealized Plot of Dose-Response Relationship (Health 1987)

18 Biomagnification of Pesticides in Aquatic Food Chains (Connell 1990)

19 Possible Movement and Fate of a Contaminant after Absorption into the Bloodstream of a Fish (Health 1987) 19


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