Bugger, doesn't mercury also accumulate in lakes as fallout from coal-fired power plant emissions? I believe there used to be coal-fired power plants in Seattle. Also, few here seem concerned, but the PCB levels in Lake Washington fish were very high, in the case of squawfish the highest level ever recorded in fish in Washington, 1071 parts per billion. Cutts and perch had lesser levels, but still elevated at 377 ppb and 191 ppb respectively. I have eaten perch from the lake before, but won't anymore. I've also caught many cutts, but always released them.