A new water quality report to the U.S. and Canadian governments warns about ongoing chemical pollution in the Great Lakes.
The International Joint Commission report comes as the two national governments renegotiate a Great Lakes Water Quality Agreement.
IJC Science Advisory Board member David Carpenter said the lakes contain chemicals like DDT and PCBs even though they are no longer used in the region. They remain in lake sediments and airborne traces reach the Lakes from nations where they are still in use.
"These chemicals are found in Great Lakes fish at concentrations that exceed in many cases, indeed in most cases, those concentrations that our health agencies in both governments determine to be dangerous to human health," Carpenter said.
The report warns of emerging chemicals of concern like pharmaceuticals that reach the lakes through sewage systems.
IJC U.S. Co-Chair Lana Pollack said progress made to clean up the lakes in past decades has slowed.
"Frankly, that progress has leveled, and in some areas, is actually sliding backwards," Pollack said.
The report also said excessive nutrients — often fed by agricultural runoff — are creating new problems.
The condition, called eutrophication, comes from nutrients like phosphorous feeding algae growth. Algae blooms can steal oxygen from water, killing fish. The nutrients come from inadequate waste water and septic systems, farm runoff and industrial livestock operations.