Did you know that although the manufacture and sale of Polychlorinated biphenyls (PCBs) has been banned in the US and Canada since 1977, PCB’s remain above the human consumption guidance levels for game fish in all five Great Lakes? In addition, due to the way PCBs biodegrade and bioaccumulate, fish tissue contains the most toxic components of PCB mixtures. People who receive exposure by eating game fish may be at more risk than people who receive comparable exposures to in-use PCBs. Of all the Great Lakes, Lake Ontario has the highest average water concentration of PCBs, followed by Lake Erie and the Upper Great Lakes.
As the use of PCBs was not banned outright, environmental concentrations drop slowly due to the re-introduction of material from capacitors, transformers, ballasts, and other uses. As recently as 2010 it was estimated that there were over 1,000,000 transformers still in operation containing >50 parts per million (ppm) of PCB oil. Here at Paradigm, we continue to find PCBs in these electrical products, as well as in more common construction materials such as paints and caulks where potential exposure is less obvious and more controllable. For more information about compounds of concern in waterways, see the Binational Summary Report.