That poison is PCBs, poly chlorinated biphenyls, once used everywhere for cooling and insulating electrical transformers and coloring newspaper comics. PCBs were even sprayed on country roads to keep dust down.
Marine scientists are concerned that the oceans are so polluted with the dangerous chemicals.
In an up-coming Marine Pollution Bulletin, Canadian scientists describe how orcas now rank as the most contaminated cetacean in the world, partly because they eat other marine life whose fatty tissues are filled with PCBs. High PCB concentrations damage immune systems. The Committee on the Status of Endangered Wildlife in Canada this April listed the northern Pacific Ocean's resident orcas as threatened. The population has dropped more than ten percent in the past three years. PCBs are among sixteen organic pollutants that European countries in the United Nations Economic Commission for Europe have finally agreed to ban.