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Green Chemistry Module for Environmental Chemistry

Green Chemistry Module for Environmental Chemistry. A Project with Major Support from the Camille and Henry Dreyfus Foundation Special Grant Program in the Chemical Sciences

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Green Chemistry Module for Environmental Chemistry

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  1. Green Chemistry Module for Environmental Chemistry • A Project with Major Support from the Camille and Henry Dreyfus Foundation Special Grant Program in the Chemical Sciences • Additional support was provided by the ACS, the University of Scranton Faculty Development Fund and the Chemistry Department

  2. Topic: Sea-nine Antifoulant A Marine Pesticide

  3. Insecticides Herbicides Disinfectants Rodenticides Algicides Molluscicides Pisicides Fungicides Avicides Chemical Pesticides

  4. Foulants • Soft Foulants (algae and seweed) • Hard Foulants (barnacles and diatoms)

  5. $ Costs of Fouling • Increased fuel consumption, $3 billion/year • Increased time in Dry-dock, $2.7 billion/year $ To clean ship $ For being out of service

  6. Environmental Costs of Fouling • Increased consumption of fossil fuels (a nonrenewable resource) • Increased formation of carbon dioxide (a greenhouse gas) • Increased formation of other atmospheric pollutants (nitrogen oxides, sulfur oxides, unburned hydrocarbons, ozone etc.)

  7. Antifoulants • Used to control the growth of marine organisms (algae and seaweed-soft foulants; barnacles and diatoms-hard foulants) • Usually mixed with the paint as it is applied to the hull • Slowly leach form the surface of the hull

  8. Organotin Antifoulants • Tributyltin Oxide TBTO

  9. Environmental Concerns of TBTO • Half-life of TBTO in seawater is > 6 months • Bioconcentration, 104 • Chronic Toxicity • Thickness of oyster shells • Sex changes in whelks • Imposex in snails • Immune system in dolphins and others?

  10. Ban on Organotin Antifoulants • US -Organotin Antifouling Paint Control Act of 1998 (OAPCA) • Ban by Japan • International Maritime Organization (IMO) complete ban on 1/1/03

  11. Environmentally Preferable Antifoulants • Ideal Properties • Rapid degradation • Nonhazardous environmental concentrations • Limited bioavailability • Toxic only to target organisms • Minimum Bioconcentration

  12. Sea-Nine 211 Antifoulant • Rohm and Haas • Presidential Green Chemistry Challenge Award • Active ingredient 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOI) • Mode of action

  13. Environmental Risk • ER= f(toxicity and exposure) • DCOI limits ER by limiting exposure

  14. Acutely toxic to a wide range of marine organisms (effective anitfoulant) Rapid biodegradation to nontoxic products (½ life < 1hour) Low Bioconcnetration (bioconcentration =13) Environmental Conc. < Acute Toxicity level No Chronic Toxicity Rapid partitioning to the sediment (low bioavailability) Properties of DCOI

  15. Biodegradation of DCOI

  16. Risk Quotient RQ = PEC/PNEC • DCOI RQ = 0.024-0.36 • TBTO RQ = 15-430 PEC (predicted environmental concentration) PNEC (predicted no-effect environmental concentration)

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