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Human Health and Toxicology

Human Health and Toxicology. Major Human Health Issues:. Focus of Epidemiologists : scientists who investigate the ecology of a disease in a population

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Human Health and Toxicology

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  1. Human Health and Toxicology

  2. Major Human Health Issues: • Focus of Epidemiologists: scientists who investigate the ecology of a disease in a population • ecology of a disease: source, manner in which it is spread, rate of spread, manner of infection, time line of infection, targets of infection

  3. Basic Measures of Human Health • Life Expectancy: How long people are expected to live (average of age of people when they die) • Infant mortality: How many infants in 1000 die before the age of one

  4. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  5. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  6. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  7. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  8. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  9. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  10. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  11. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  12. Comparison of Human Health in Highly Developed Countries (HDC) and Low Developed Countries (LDC)

  13. Reasons for Increased Longevity with Development: • Sanitation: Decreases spread of disease, especially those related to human waste (cholera and diarrhea) – prevents the spread of parasites and disease causing microorganisms • Vaccinations: near elimination of disease (mumps, polio, measles) • with increased development the cause of death moves away from infectious disease caused by microorganisms (influenza, tuberculosis, gastritis, cholera) to chronic disease associated with aging (cancer, cardiovascular disease and chronic obstructive pulmonary disease), many of which are preventable by life style choices

  14. Health Issues in HDC: • McDonalds…..obesity and overweight • Overweight: 10 – 15 % over proper weight range – includes muscle, bone, fat and water • Obese: more than 15% over proper weight range – usually due to excess fat • Proper Weight Range: Body Mass Index – relationship of a person’s weight and height – BMI = (weight x 740)/(height in inches)2 • Compare to accepted standards to determine underweight, healthy weight, overweight or obese

  15. Health Issues in the LDC: • mostly due to sanitation, lack of medical supplies and malnutrition • HIV/AIDS

  16. Emerging and Reemerging Diseases • Emerging diseases: cross from other species to the human population • Monkey Pox • Asian Bird Flu • HIV • West Nile Virus • Lyme Disease

  17. Reemerging Disease: at one point were under control but are increasing • Tuberculosis, small pox • malaria • Reasons For Re-emergent Diseases- decrease in ability to fend off disease (HIV) • increased resistance to drugs and treatments

  18. Environmental Pollution and Disease Cause vs. Association Cause – direct link between a pollutant and the detrimental effects Ex: Radon gas and lung cancer Lead and nervous system degeneration

  19. Association: link between pollutant and disease is less clear due to:- a person’s genetic makeup - diet - levels of exposure (chronic or acute) - other health issues (other diseases or conditions, smoking) - age (children tend to be more susceptible, elderly have weakened immune systems) - local environment

  20. Pollutant: a chemical or waste put into the air, water or soil that makes the environment unfit for living organisms

  21. Toxins vs. Toxicant Toxin: poisonous substance that is a protein – manufactured by a living organism Ex: poison secreted by the skin of a Poison Arrow Frog, Venom, Poison on Poison Ivy Toxicant: a man-made chemical that causes biological harm • degrade natural conditions disrupting biological functions and natural cycles • affect human health

  22. Pollutants that cause the most harm are those that persist, bioaccumulate and biomagnify. • Ex: DDT – DichloroDiphenylTrichloroethane – insecticide • used to spray mosquitoes in order to stop the spread of malaria • DDT is consumed by organisms and stored in fatty tissue • In the fatty tissue it slowly degrades into DDE (Dichlorodiphenyldichloroethylene)

  23. DDT and DDE at low levels are not very toxic but both persist, bioaccumulate and biomagnify build up to toxic levels • EX: Eggs of Large Predatory Birds (Bald Eagle) have thin egg shells

  24. Persistence: chemicals that remain in the environment because they are not broken down by natural processes or decomposers – decomposers lack the enzymes necessary for the degradation of the toxicant

  25. Bioaccumulation/Bioconcentrate: pollutants are injested or absorbed by animals or plants and remain in the body - in animals the pollutants typically are stored in fatty tissue (DDT) or muscle tissue (mercury) – in plants the pollutants are typically stored in the central vacuole of the cell - at certain levels, the pollutant may not have any noticeable effect, but over time increased accumulation can result in thedeterioration of the organism

  26. Biomagnification/bioamplification: organisms in higher trophic levels tend to have higher concentrations of toxic substances in their bodies than lower trophic level organisms • as the toxic substance is consumed by lower trophic levels it is bioaccumulated in the tissues • as the lower trophic levels are consumed, the toxins are stored in the higher trophic levels • since the higher trophic levels consume more and more of the lower trophic level organisms, the level of the toxic substances increases in the tissues • although the levels of the substance are not at toxic levels for the lower trophic organisms, the higher trophic organisms can quickly progress to a toxic state due to the rapid accumulation of the compound

  27. Comparison of Biomass and Biomagnification

  28. Biomagnification of Mercury • Mercury mainly enters the environment from the combustion of fossil fuels • also from industrial and chemical waste disposal • - Mercury enters water ways by leaching and precipitation and migrates to the benthic levels. • Bacteria in the bottom mud converted it to methyl mercury, an extremely toxic soluble compound • Methyl mercury enters the food chain in the phytoplankton and is accumulated in the tissues of fish • passes up the trophic levels to humans who fish in contaminated waters.

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