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Do Now

Do Now. President Obama mentioned several times that we need to “invest” in things like electric cars. Is this helping the problem of diversifying our energy needs and reducing CO 2 gases. Thoughts?. Homework. Due today in class:

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Do Now

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  1. Do Now • President Obama mentioned several times that we need to “invest” in things like electric cars. • Is this helping the problem of diversifying our energy needs and reducing CO2 gases. • Thoughts?

  2. Homework • Due today in class: • Finish Reading chapter 14 - should already be completed. • Vocab Quiz tomorrow • Begin to review – The Final Exam will consist of Chapters 8 - 14

  3. BPa • Bisphenol A binds to estrogen receptors • Phthalates in plastics disrupt hormones • Toys, perfumes, makeup • Birth defects, cancer, reproductive effects

  4. Toxins and chemicals route of travel

  5. Boards • Explain the term below. • Pesticide drift

  6. Toxins and chemicals route of travel • Chemicals can travel by air • Their effects can occur far from the site of use • Pesticide drift = airborne transport of pesticides • Synthetic chemicals are found globally

  7. Boards • Breakdown products – explain this term

  8. Breakdown of toxins and chemicals • Toxins can degrade quickly and become harmless • Or they may remain unaltered and persist for decades • Rates of degradation depend on the substance, temperature, moisture, and sun exposure • Breakdown products = simpler products that toxicants degrade into • May be more or less harmful than the original substance • DDT degrades into DDE, which is also highly persistent and toxic

  9. Increase in toxins • Toxicants in the body can be excreted, degraded, or stored • Fat-soluble toxicants are stored in fatty tissues • Bioaccumulation = toxicants build up in animal tissues • Biomagnification = concentrations of toxicants become magnified • Near extinction of peregrine falcons and bald eagles

  10. How do they test chemicals • Animals are used as test subjects • Mammals share evolutionary history • Substances that harm rats and mice are likely to harm us • Dose-response analysis = measures the effect a toxicant produces or the number of animals affected • Dose = amount of substance the test animal receives • Response = the type or magnitude of negative effects

  11. Chemical harm • LD50/ED50= the amount of toxicant required to kill (affect) 50% of the subjects • A high number indicates low toxicity • Threshold dose = the level where certain responses occur • Theo Colburn’s Our Stolen Future (1996) describes how synthetic chemicals may be changing hormones

  12. Exposure • Acute exposure vs. Chronic exposure • Acute = high exposure to a hazard for short periods of time and Chronic exposure = low exposure for long periods of time • Risk = the probability that some harmful outcome will result from a given action, event, or substance

  13. Philosophy of harm • There are two basic principles surround harm / safety: • Innocent-until-proven-guilty approach or Precautionary principle • Explain the difference • Role of the government: • The FDA: monitors food, food additives, cosmetics, drugs, medical devices • The EPA: regulates pesticides and chemicals not covered by other laws

  14. Cracking down on Toxins • The EU’s REACH program (Registration, Evaluation, Authorization, and Restriction of Chemicals) shifts the burden of proof for safety to industry • Stockholm Convention on Persistent Organic Pollutants (POPs) POPs = toxic, persistent chemicals. Enacted in 2004 and ratified by over 150 nations. • Stockholm Convention sets guidelines for phasing out these chemicals

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