It is known to cause deformities and reproductive failure in animals. Today its level in the lake has declined to concentrations less than the guidelines set by the Great Lakes Water Quality Agreement of 1978. Because of its insolubility and retention in sediment, however, the amount of DDT has leveled off and shown no further decline. The largest sources of this compound today are pulp and paper mills. Achieving a goal of eliminating all toxins entering our Great Lakes will not be an easy task.
Many companies still feel that resources like Lake Erie are their to exploit.
Also, as shown earlier, many of the toxins which are no longer discharged are still creating problems because of their insolubility and affinity to remain in the environment. Several steps have been taken to help in the reduction and elimination of toxins. The Water Quality Act of 1987 stressed the importance of controlling the discharge of toxic chemicals and compounds to surface waters. Four of these are in Ohio. They include the Ashtabula, Black, Cuyahoga and Maumee rivers.