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Chlorinated Organics

Chlorinated Organics. General Properties/Action. The C- Cl bond is very strong and does not easily break down Persistence in the environment/organism Non-polar Not water soluble, but fat soluble May interfere with metabolism Can be useful as a pesticide

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Chlorinated Organics

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  1. Chlorinated Organics

  2. General Properties/Action • The C-Cl bond is very strong and does not easily break down • Persistence in the environment/organism • Non-polar • Not water soluble, but fat soluble • May interfere with metabolism • Can be useful as a pesticide • Can be problem for non-target organism • May affect nervous system

  3. DDT • Early synthetic pesticide – first used large-scale in WWII to control insects/lice • Thought of as a “Wonder Chemical” • Highly exposed soldiers complained of aching joints, tremors and depression • Widely used on crops with little regard for recommended dose rates • Thought to cause thin egg shells in birds • Banned (NA) in early 1970s

  4. PCBs • Poly Chlorinated Biphenyls • Over 200 possible compounds • First synthesized in 1880s, commercial use started in 1929 • Oil in electrical transformers, Painted on hydro poles, Plasticizers, De-inking fluids, Carbon-less copy paper, Cosmetics, Paints • Long term exposure is highest concern • Chloracne, general fatigue, headaches, joint pain

  5. Dioxins • 75 different possibilities • No known use; never intentionally produced • A possible contaminant in PCBs and a few other chemicals • By-product of paper bleaching, (now-banned) 2,4,5-T manufacture, burning some plastics (Saran) • Some spectacular disasters • Agent Orange • Times Beach, Missouri • Seveso, Italy • Milk cartons, coffee filters, diapers, napkins

  6. Dioxins, part 2 • Media: “deadly dioxin”, “most toxic substance known” • It is toxic, but other things are more toxic • Long-term low-dose exposure: • Chloracne • Birth defects • Immune function

  7. ChloroFluoroCarbons (CFCs) • Another “Wonder Chemical” • Non-toxic, non-flammable, cheap, easy to make • Used as refrigerants, foam blowing agents, circuitry cleaners, aerosol propellants • Allowed for safe refrigeration in homes • Once released into the atmosphere, reacts with ozone to cause depletion

  8. Trihalomethane • Trichloromethane = chloroform • Used in the production of Teflon • Naturally produced by some seaweeds • By-product of chlorine treatment of water • Levels present are very low – minimal risk

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