Canada it was widely used in pest control canada it

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Canada, it was widely used in pest control  Canada, it was widely used in pest control  products until the 1960s products until the 1960s In response to increasing environmental  In response to increasing environmental  and safety concerns,  and safety concerns,  most uses most uses  of DDT in   of DDT in  Canada were phased out by the mid-1970s  Canada were phased out by the mid-1970s  and  and  all uses all uses  by 1985  by 1985
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The " The " second generation second generation " pesticides " pesticides included  included  synthetic organic compounds synthetic organic compounds Agricultural chemicals & food production Pesticides: historical perspective Pesticides: historical perspective PCBs (polychlorinated biphenyls)
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Agricultural chemicals & food production Adhesives,   asphalt roofing materials,   carbonless copy paper,   compressor oil,   de-dusting agents,   dyes,   fluorescent light,   heat  transfer fluid,   inks,   lubricants,   paints,   pesticides,   space heaters,   tar paper,   waxes,   fire  retardants Common uses of PCBs (before 1977) Common uses of PCBs (before 1977)
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Agricultural chemicals & food production Their primary use, however, was as a  dielectric  fluid  (high electrical resistance)  in electrical equipment Because of their stability and resistance to  thermal breakdown as well as their insulating  properties they were  the fluid of choice for  transformers and capacitors
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Agricultural chemicals & food production PCBs in Canada PCBs in Canada Of the  40,000 tonnes  of PCBs imported into  Canada, just over  24,000 tonnes  can be  accounted for today Of this amount, 61% has been found in electrical  transformers still in use, another  12% in electrical capacitors, and 27% in storage  waiting for disposal
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Agricultural chemicals & food production PCBs in Canada PCBs in Canada Most of the remaining 16,000 tonnes of PCBs is  assumed to have already been dispersed in the  environment in various fashions Because of this dispersal over the years, traces  of PCBs can be found in all reaches of Canada  and the world in virtually every  living organism, including humans
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Agricultural chemicals & food production Pesticides: historical perspective Pesticides: historical perspective The “ The “ third generation third generation " pesticides " pesticides aldicarb and pyrethroids aldicarb and pyrethroids     1) Less persistent = More soluble! 1) Less persistent = More soluble!
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