Toxic Substances and Areas of Concern

Although many sources of contamination have been reduced, legacy contamination remains in the Great Lakes area. It includes contaminants largely left over from past practices but that continue to recirculate through the environment. Contaminants of emerging concern such as, pharmaceuticals, have been detected in the Great Lakes in recent years and also pose potential but unknown threats to ecosystems. Efforts to clean up toxic substances are underway in 30 U.S. Great Lakes Areas of Concern as part of GLRI. USGS is working with others to improve the health of the Great Lakes fisheries by enhancing fish habitat for the Huron Erie corridor; identifying the types and locations of legacy contaminants and contaminants of emerging concern in major tributaries to the Great Lakes; examining mercury processes including how mercury enters the food chain, how it affects the fish, and public health; using birds as indicators of contaminant exposure in the Great Lakes; and supporting restoration of beneficial uses in Areas of Concern by measuring the conditions of plankton and organisms that live on the lake/river bottom.