Even with so many improvements in water quality since the Clean Water Act went into effect, pollution is finding its way to Michigan waterways, and then into the fish. 
“Mercury and toxic PCBs emitted into the atmosphere from sources around the world rain down on Michigan’s lakes and rivers, contaminating fish and posing health threats to people who eat too much tainted fish.
It’s a problem Michigan cannot solve on its own.
The reason: 75 percent of the mercury and 55 percent of the PCBs that fall out of the sky and into the Michigan waters come from outside the state. Each year, about 6,000 pounds of mercury ride the wind into Michigan, according to U.S. Environmental Protection Agency estimates.
For the first time, the Michigan Department of Environmental Quality has drafted plans for reducing PCBs and mercury in fish and surface waters to safe levels. But preliminary documents obtained by Bridge paint a sobering picture of the daunting task at hand.
Reducing PCBs and mercury in Michigan fish to safe concentrations will require cutting global PCB emissions by 94 percent, and global mercury emissions 82 percent, according to the state’s draft cleanup plans, known as Total Maximum Daily Limits (TMDLs) for PCBs and mercury. Getting there will take about 50 years for PCBs, possibly longer for mercury, according to state officials.”
Read the complete article at the link above.