Chapter 17: Environmental Hazards and Human Health

1. Chapter 17: Environmental Hazards and Human Health Kelsey Kushner Megan Stellini

2. Global HIV/ Aids • Aquired immune deficiency syndrom (AIDS) • Caused by infection of human immunodeficiency virus (HIV) • Cripples the immune system • Spread around the world, mostly in African Countries • No way to cure it -> only help people to live longer

3. Health Hazards we Face • Risk are usually expressed as Probabilities • Risk = the probability of suffering harm from a hazard that can cause injury, death, disease, economic loss, or damage 5 major types of Hazard: • Biological hazard: bacteria, viruses, parasites, protozoa, and fungi • Chemical hazard: harmfulchemicals in air, water, soil, and food. • Physical hazard: fire, earthquake, volcanic eruptions, floods, and storms • Cultural Hazard: unsafe working conditions, unsafe highways, poverty, criminals • Lifestyle Hazard: smoking, overeating, alcohol, unsafe sex

4. Disease can Spread • Nontransmissible disease = caused by something other than a living organism and does not spread from one person to another (asthma, diabetes, malnutrition) • Infectious Disease = caused when a pathogen such as bacterium invades the body and multiplies in cell and tissue (flu, HIV, malaria) - Leading cause of Disease in 1900 • Transmissible disease = infectious disease that can be transmitted from one person to another (HIV, flu, measles) • DALYs – (disability adjusted life years) measure total disease burden in a population

5. World Health Organization = developing Global Health Atlas which contains database and map based on health statistics in the World

6. Genetic Resistance Genetic Resistance to Antibiotics • Lack of preventing disease because of the reproductive rate of bacteria that allows bacteria to become genetically resistant to an increasing number of antibiotics in natural selection • Spread of Bacteria • Overuse of Pesticides • Overuse of Antibiotics (MRSA)

7. Animal to Human • Wildlife moves infectious disease to humans • Ecological medicine = tracking down the connections between wildlife and humans -> prevent spread of disease • Clearing of forests -> results in movement of animals such as mosquitoes (Malaria) • Global Warming • Bush Meat trade -> dead animal blood may contain viruses that are then exposed to humans • Factory meat – E coli bacteria transferred from animals to humans when consumed

8. SOULTIONS • WHO (World Health Organization) • Solutions: • Increase research on tropical diseases and viruses • Reduce Poverty • Decrease malnutrition • Improve drinking water • Reduce use of unnecessary antibiotics • Educate people taking antibiotics • Require hand washing

9. Chemicals cause Cancer • Toxic chemicals- cause permanent/ temp. harm or death • Carcinogens (chemicals, radiation, or viruses that cause cancer) • Mutagens (chemicals, radiation, or viruses that cause mutations) • Teratogens (chemicals, radiation, or viruses that cause birth defects) • PBCs • Chlorine containing organic compounds used as lubricants, hydraulic fluids and electrical insulators • Banned because cause Liver cancer • Found in water, air, food chain, and soil

10. Affect our Systems • Immune System (disease) - Infectious bacteria, viruses, and protozoa 2. Nervous System (brain, spinal cord, peripheral nerves) - Retardation, ADD, learning disabilities, paralysis, and death 3. Endocrine System (glands that release hormones) - Learning behavior, growth, sexual reproduction, development

11. Mercury • (Hg) is a teratogen and potent neurotoxic • Interferes with nervous system • Released into the air from rocks, soil, volcanoes, and vaporization from ocean (fish) • Brain damage in children • Harm kidneys, heart, and immune system in adults

12. Toxicology • The study of the harmful effects of chemicals on humans and other organisms • Study of poisons • Toxicity: a measure of how harmful a substance is (ability to cause injury, illness, or death) • Harmful if ingested in a large enough quantity

13. At what level of exposure to a toxic chemical will it cause harm? • Dose: amount of harmful chemical that a person has ingested, inhaled, or absorbed through skin • Age (children to adults) • Genetic makeup • Multiple Chemical Sensitivity (MCS) • Solubility and Persistence (resistance to breakdown) • Biological magnification: concentrations of toxins increase through the trophic levels • Response: damage to health resulting from exposure • Acute (immediate) or chronic (permanent)

15. Protecting Children from Toxic Chemicals • Infants and young children are more susceptible • 1. breathe more air, drink more water, eat more food per unit of body weight • 2. exposed to toxins in dust or soil (mouth) • 3. usually have less well-developed immune systems and body detoxification processes • EPA (2003)  children face a risk 10 times higher than that faced by adults

16. Estimating Toxicity • Live laboratory animals • Mammals systems are like humans (small and reproduce quickly) • 2-5 years/hundreds to thousands of test animals/$2 million per substance test • Dose-response curve: • lethal dose • Median lethal dose (kill 50% within 18 days) • Nonthreshold dose-response model: any dosage causes harm that increases with the dosage • Threshold dose-response model: threshold dosage must be reached before any detectable harmful effects occur

18. Alternatives to Animal Testing • Computer simulations • Testing with tissue cultures, chicken egg membranes, and individual animal cells • High-speed robot testing devices can now measure the biological activity of more than one million compounds a day to help determine their possible toxic effects

19. Are Trace Amounts of Toxic Chemicals Harmful? • Honestly: in most cases we don’t know • Too little data • Difficulty of determining the effects of low levels of these chemicals • Argument  life expectancy has been increasing in most developed countries for decades

20. Comparative Risk Analysis (1) • High risk Health Problems • Indoor/outdoor air pollution • Worker exposure to industrial/farm chem • Pollutants in drinking water • Pesticide residues on food • High risk environmental problems • Global climate change • Stratospheric ozone depletion • Wildlife habitat destruction/alteration • Species extinction/loss of biodiversity

21. Comparative Risk Analysis (2) • Medium-risk Ecological Problems • Acid deposition • Pesticides • Airborn toxic chemicals • Toxic chemicals, nutrients, and sediment in surface waters • Low-risk Ecological Problems • Oil spills • Groundwater pollution • Radioactive isotopes • Acid runoff to surface waters • Thermal pollution

23. Poverty, Gender, and Lifestyle • High death toll resulting from poverty: • Malnutrition, increased susceptibility to normally nonfatal infectious diseases, and often-fatal infectious diseases transmitted by unsafe drinking water • AVOID risks like…. • Smoking, exposure to smoke, overconsumption of foods containing cholesterol and saturated fats, drinking more than two glasses of alcohol per day, excess sunlight, unsafe sex

24. Death From Smoking • World’s most preventable major cause of suffering and premature death among adults • Kills an average of 14,800 people per day • By 2030, the annual death toll is projected to reach more than 8 million (average of 21,900 deaths per day) • Only 1 in 10 people succeed in quiting • Passive Smoking: second-hand smoke • Children more likely to develop allergies/asthma • In 2006, CDC estimated 3,000 lung cancer deaths and 46,000 heart disease caused by second-hand smoke

25. Encouraging News • Average # of cigs smoked per person in the US declined by 56% between 1976 and 2006 • Dropped globally by 16% between 1988 and 2006

26. How People Evaluate Risks • 1. Fear • 2. The Degree of control we have • 3. Whether a risk is catastrophic, not chronic • 4. Optimism bias (same risks don’t apply to them) • 5. Instant gratification (fake tanning)

27. How to ACTUALLY Evaluate Risks • 1. Compare risks • 2. How much risk are you willing to accept? • 3. Determine the actual risk involved • 4. Concentrate on evaluation and carefully making important lifestyle choices