Chapter 14: Environmental Health and Toxicology www.aw-bc.com/Withgott

Environmental Health assesses environmental factors that influence human health and quality of life natural human-caused

Physical Hazards natural disasters earthquakes volcanic eruption fires floods blizzards landslides hurricanes droughts UV radiation difficult to predict areas of high risk can be determined

Chemical Hazards synthetic chemicals society produces disinfectants (Lysol products) pesticides (DDT)

Biological Hazard ecological interaction between organisms infectious diseases swine flu: virus tuberculosis: bacteria Mycobacterium tuberculosis malaria: parasite Plasmodium sp. cholera: bacteria Vibrio cholerae

Cultural Hazards behavioral choices location we live in smoking, sunbathing, drug use location we live in near an active volcano Alaskan volcano 2006 apod.nasa.gov/apod/ap060607.html

socioeconomic status occupation Cadillac Heights hazardous work or lack of safety equipment www.dallasnews.com Dallas Flood June 2007

Disease major factor of environmental health www.aw-bc.com/Withgott

Indoor Health Hazards radon lead highly toxic gas seeps up from the ground in certain areas lead water from lead pipes and lead paint in homes and toys damages brain, liver, kidney and stomach learning disabilities behavioral abnormalities anemia hearing loss death

Indoor Health Hazards asbestos PBDEs form long thin microscopic fibers used in insulation (sound, heat) resists fire dangerous when inhaled: asbestosis & cancer PBDEs fire-retardant used in electronics, plastics and furniture evaporates at very low rates accumulates in tissues may affect nervous system and cause cancer banned in the EU

Toxicology study of poisonous substances environmental toxicology deals with toxics discharged in the environment on humans other animals ecosystems

Environmental Toxicology natural toxins radon, arsenic, mercury exuded substances from plants and animals human-made toxins wastewater contaminants pesticides & herbicides Silent Spring by naturalist Rachel Carson effect of DDT on humans, animals and ecosystems DDT is still in use in tropical areas to control diseases

Types of Toxicants carcinogens mutagens teratogens causes cancer causes mutations in fetus teratogens affects fetus during gestation causing birth defects Thalidomide

Types of Toxicants allergens neurotoxins weakens immune system increase in asthma neurotoxins inorganic: heavy metals (lead, mercury) Minamata case organic: pesticides (DDT, mothballs, nerve gas) some are very stable and can last decades, others may only last hours

Types of Toxicants endocrine disruptors interfere with hormones affects growth, reproduction, behavior, brain function similar to hormones so they "mimic" them certain pesticides→ feminization of males possible cause of human sperm count drop worldwide possible cause of increase rates of testicular cancer undescended testicles genital birth defects in men female breast cancer

Effects of Endocrine Disruptors www.aw-bc.com/Withgott

Other Effects of Endocrine Disruptors brain functioning PCB contamination of food (fish) lower birth weight of babies smaller heads weak and jerky reflexes tested poorly in intelligence tests

Means of Toxins' Disperse water many are soluble in water runoff concentrates toxins in surface waterways enters tissue through drinking or contact air pesticide drift toxins appeared in tissues of arctic polar bears and antarctic penguins thought to be due to global atmospheric circulation

Distribution of Toxins www.aw-bc.com/Withgott

Toxins in the Food Chain Bioaccumulation stored in tissues according to its solubility Biomagnification increase in toxin concentration up in the food chain Bald eagle case related to DDT population decrease of polar bears

Epidemiology Studies application of experimentation due to conditions in the environment effect of a contaminant in the air to a population already established drawback takes too long many other factors may affect the health of the subjects statistical association between health hazard and effect but it does not confirm it as the cause of the problem

Dose-responce Toxicity effect of toxins according to amount in the system/body LD50→ lethal dose for 50% low LD50 means high mortality high LD50 means low mortality ED50→ effective dose for 50% half of the population gets sick but doesn't die Threshold toxin level above which a responce is observed

Exposure vs Responce acute responce chronic responce responce to a high exposure during a short period of time Union Carbide accident in India chronic responce responce to a low concentration of a toxin but during a long period of time exposure to Teflon synergistic effect unpredicted consequences of mixing toxins sum cancel multiply or exacerbate

Risk Assessment & Risk Management Assessment: collection and interpretation of scientific data identifying outlining problems expressed in probability risk of crashing if driving too fast Management: formulation of policy to minimize risk influenced by political pressure considers economics and ethics EPA, CDC, FDA banning of Seldain D banning of DDT containing cholera

Philosophical Approaches innocent-until-proven-guilty innovation goes ahead doesn't slow down technology can result in disasters recall Vioxx (short period of testing) vitamins & herbs (unregulated)

Philosophical Approaches harmful until proven otherwise precaution principle experimentation has to be done thoroughly long process] regulated medications

EPA Federal Insecticide, Fungicide and Rodenticide Act of 1947 assured the effectiveness of the product EPA was created to protect the public and environment from toxic chemicals using risk assessment and management EPA examines the data from the manufacture assesses the possible risks to humans and environment approves, denies or sets limits to use

Toxic Substances Control Act (1976) regulation of synthetic chemicals by the EPA criticized as too weak screening of industry is minimal EPA needs to show proof of toxicity and not the other way around only 10% have been tested for toxicity only 2% have been tested for carcinogens fewer than 1% are government regulated none have been tested for endocrine, nervous or immune system damage

International Regulation Stockholm Convention on persistent Organic Pollutants of 2004 "dirty dozen" guidelines to phase off these chemicals REACH pushes innovation of new chemicals to do the same job but be less toxic

Dirty Dozen www.aw-bc.com/Withgott The End