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The Displacement of PCBs in Environment

The Displacement of PCBs in Environment. ——The PCBs pollution status of Guangzhou City. ES0710182009 Wang Jiao. What are PCBs.

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The Displacement of PCBs in Environment

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  1. The Displacement of PCBs in Environment ——The PCBs pollution status of Guangzhou City ES0710182009 Wang Jiao

  2. What are PCBs • PCBs are a class of chlorinated aromatics, formed with benzene as raw materials and metal as catalyst at high temperature, its molecular formula being (C10H10) Cln. There are a total of 209 congeners according to the number and different positions of chlorine atoms to be replaced. • PCBs are often used in heat exchange agent, lubricants, transformers and capacitors, and widely used in power industry, plastics processing industry, chemicals and printing fields. • PCBs are the first to be included in the POPs, and a member of the Dirty Dozen.

  3. The Characteristics of PCBs • Persistence: with a strong resistance to the biological metabolism, photodegradation and chemical decomposition; • Long-term residue: hydrophobic lipophilic, accumulated in fat, reaching the toxic concentrations through amplification in the food chain; • Semi-volatile: long-distance displacement and deposition in the atmosphere;

  4. PCBs hazards • Induce lesions and cancer: Japan and Taiwan encountered with the outbreak of rice bran oil events in 1968 and 1979 respectively; • Affect the breeding of mammals and birds; • Cause water and air pollution;

  5. Rice Bran Oil Event PCBs Rice bran oil

  6. The Displacement of PCBs 0.6% reacts with HO then disappear Rainwater, (wet) deposition Exhaust gas Effluent Volatilization Stockpile Rainwater, (wet) deposition Deposition Volatilization（weak） Biodegradation Reversible adsorption

  7. The Content of PCBs • Atmosphere: 307.2 ~ 2720.8pg/m3; mid-level • Water sediments (Pearl River): 485ng/g; • Water: 2.3ng/l; • Soil: 6 ~ 151g/kg; Tibet: 0.625 ~ 3.501g/kg

  8. In 1977 all countries successively suspended its production, and by 1980, world’s total production amount of PCBs was one million tons; • The production of PCBs in China started in 1965, and ended in the 1980s, the estimated total output being nearly 10.4 tons over the years; • The total amount of PCBs currently existing in the world's oceans, soil and atmosphere appears to be 25 to 30 tons.

  9. Thanks

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