The IJC was created as part of the Boundary Waters Treaty of 1909. This study and its recommendations inspired not only some highly successful controls on phosphorus but the Great Lakes Water Quality Agreements. The first of the agreements, in 1972, called for further research, monitoring, and general pollution control. The second, in 1978, built upon the first, limited loading of some contaminants and called for elimination of others. The third, in 1987, widened its breadth and emphasized the health of ecosystems in the Great Lakes Basin.
Critical pollutants are PCBs, mercury, DDT, dioxin, chlordane, furan, and dieldrin.
Private industry is polluting less, voluntarily and because of regulations, including those requiring certain industrial facilities to publish Toxic Release Inventories that detail how much of certain toxins they generate and what they do with it. An Environmental Atlas and Resource Book explains that even though water concentrations of particular chemicals may be so low as to be undetectable, those chemicals can still accumulate to substantial levels. The Chicago-Gary area is one of the biggest perpetrators, though pollutants also are carried in on currents from far away. Encouraging is that, in 1997, the United States and Canada have signed the Great Lakes Binational Toxic Strategy, aspects of which focus on air pollution. Parts of it are already being implemented.