+ Pesticides & Toxicology

+ Pesticides Any chemical used to kill or control populations of organisms that humans consider undesirable Herbicide: weed killer Fungicide: fungus killer Rodenticide: rat and mouse killer Insecticide: insect killer

+ Advantages Saves human lives from insect/rodent transmitted diseases Increases food supplies (55% of food supply is already lost to pests) Profitable Work fast Safe if used properly

+ Disadvantages Promote genetic resistance Kill natural pest enemies Pollute the environment (close to 98% end up places they are not intended to be because they are “persistent”) Can harm wildlife and people Are expensive for farmers (only useful for 5-10 years: Pesticide Treadmill)

+ Broad Spectrum Pesticides Pesticides that kill a wide range of pests Examples: Chlorinated Hydrocarbons (Glyphosphate, DDT, Dieldrin, Aldrin, Chlordane) ALL ILLEGAL IN THE U.S. EXCEPT FOR GLYPHOSPHATE Organophosphates (Malathion (legal), Parathion (illegal)) Atrazine (herbicide legal in U.S.) DISADVANTAGES: Because they are broad spectrum, they often kill “good” species as well.

+ Pesticides Bumble bees: fXYR9FTfMhttp:// fXYR9FTfM

+ Glyphosphate World’s best selling herbicide “Roundup” produced by Monsanto Does not kill insects, animals, or leach into surrounding water Binds to soil particles and degrades within a few weeks Monsanto owns it and also produces “Roundup ready” seeds (Genetically modified to be glyphosphate resistant)

+ DDT Dichlorodiphenyltrichloroethane Rachel Carson “Silent Spring” (1962): started environmental movement Banned in U.S. in 1972 because it weakened the shells of bird eggs and was harmful to humans It is still legal in other countries Malaria controversy in Africa and Asia

+ Just because they are illegal in the U.S….. Doesn’t mean that you are not consuming it Many of the broad spectrum pesticides are still legal in other countries, which are imported here Therefore, you could be consuming these pesticides determined to be harmful by the USDA. This is the reason DDT can still be detected in U.S. citizens

+ Narrow Spectrum Pesticides Pesticides that are designed to kill specific pests Examples: Brodifacoum used to kill rodents Nuclear Polyhedrosis Virus (NPV) used to infect insects

+ Integrated Pest Management Environmentally friendly; goal is to keep the pest population down, not to eliminate Introducing natural insect predators Intercropping Mulch to control weeds Diversify crops Crop rotation Traps Barriers Chemicals only in the worst case scenario

+ Organic Farming Crops are grown with little or no use of synthetic pesticides, synthetic fertilizers, or genetically engineered crops Advantages Improves soil fertility Reduces water pollution Uses less energy (and fossil fuels) Disadvantages Lower crop yield

+ Organic Foods Do conventional foods really harm us? Not really sure, it is difficult to do such a comprehensive study over a lifetime Recent study from Harvard reports that organic foods do not have a higher nutritional value than do conventional foods However, buying organic foods does support organic farming practices

+ The Dirty Dozen & The Clean 15

+ Legislation Federal Insecticide, Fungicide, and Rodenticide Act: regulates the effectiveness of pesticides Food Quality Protection Act: set pesticide limits on food and all active and inactive ingredients must be screened for estrogenic/endocrine effects

+ Toxic Chemicals EPA released 5 most toxic chemicals to humans: 1. Arsenic 2. Lead 3. Mercury 4. Vinyl Chloride (used in some plastics) 5. PCBs (polychlorinated biphenyls)

+ Toxic Chemicals 3 Types of Toxic Chemicals: 1. Carcinogens: chemicals, radiation, or viruses that cause cancer (time lapse between exposure and cancer) Ex) Arsenic, Benzene, Chloroform, Formaldehyde, Gamma Radiation, Nickel, PCBs, Radon, UV Radiation, Vinyl Chloride 2. Mutagens: chemicals or radiation that causes mutations in DNA. Ex) Nitrite (a preservative) can turn to nitrous acid during digestion. Nitrous acid causes stomach cancer. 3. Teratogens: chemicals that cause birth defects to a fetus or embryo. Ex: Ethyl alcohol, mercury (China), lead

+ PCBs Polychlorinated Biphenyls Exist as oily liquids or solids that can enter the air as vapor Used as lubricants, hydraulic fluids, electrical insulators U.S. banned production of PCBs in 1977 after it was shown to cause cancer and learning disabilities in children PCBs breakdown VERY slowly in the environment & fat- soluble so are subject to bioaccumulation Found EVERYWHERE! In the bodies of polar bears in the Arctic, all humans bodies including mother’s milk.

+ HAA Hormonally active agents Either mimic estrogen or block androgens “Gender benders” because they can damage sexual development Increase testicular cancer and breast cancer DDT, BPA and PCBs Bhopal, India

+ BPA Bisphenol A Estrogen mimic Baby bottles, sports drink and juice bottles, microwave dishes, food and beverage can linings Leach into food when exposed to heat or acidic conditions Some studies find (from just small amounts) BPA can cause brain damage, reduced sperm count, breast caner, prostate cancer and lots more SHOULD WE BAN THESE CHEMICALS AND WAIT FOR FURTHER RESEARCH OR SHOULD WE NOT BAN THEM BECAUSE FURTHER RESEARCH IS NEEDED?

+ Toxicology Toxicity: a measure of how harmful a substance is (its ability to cause injury, illness, or death to a living organism) *Any synthetic or natural chemical can be harmful if ingested in a large enough quantity.

+ Lethal Dose Lethal Dose: the amount of a chemical needed to kill an animal Median Lethal Dose (LD50): dose that can kill 50% of the animals in a test population within an 18-day period. Dose-Responsive Curve:

+ LD50 2 Types of dose-responsive curves: 1. Nonthreshold Dose-Response Model: any dosage of a toxic chemical causes harm that increases with the dosage. 2. Threshold Dose-Response Model: a threshold dosage must be reached before any detectable harmful effects occur