Together with the Ohio Environmental Protection Agency, Ohio Lake Erie Commission, Black River and Cuyahoga River Area of Concern (AOC) Community Advisory Committees, U.S. EPA has removed the Fish Tumors or Other Deformities Beneficial Use Impairment (BUI) at both the Black River and Cuyahoga River AOCs. These BUIs were removed on October 16 and August 3, 2023, respectively. BUIs are designations listed in the 1987 amendment to the Great Lakes Water Quality Agreement that represent different types of significant environmental degradation (see Beneficial Use Impairments for the Great Lakes AOCs to learn more).
Historical industrial pollution in the Black and Cuyahoga Rivers resulted in poor water quality and sediments contaminated with toxic compounds that negatively impact fish health, including metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). Elevated PAHs in particular can cause liver tumors and external deformities in fishes - especially in more susceptible bottom-dwelling or resident species such as brown bullhead catfish and smallmouth bass. Fish populations in these rivers suffered from excessive rates of both internal (liver tumors) and external (deformities, eroded fins, lesions, and tumors) malformations as a result of sediment contamination, prompting the initial designation of the Fish Tumors and Other Deformities BUI in both AOCs.
Regulatory policies and declines in industrial activity have helped control or reduce many of the sources of industrial contamination in the Black River and Cuyahoga River AOCs, which has led to significant improvements in water quality in the rivers. State and federal partners completed additional remediation work in several riparian and upland locations adjacent to the Black River AOC where elevated contaminant levels were still contributing to this BUI. Recent assessments showed reduced levels of sediment contaminants in the Black and Cuyahoga River AOCs, and ongoing remediation work is expected to continue to improve conditions in the Cuyahoga River AOC.
State and federal partners conducted fish surveys in these rivers to assess the prevalence of internal and external malformations. In order to remove the Fish Tumors or Other Deformities BUIs in both of these AOCs, the State of Ohio requires that malformations in fish populations must be at rates below 5%. Assessments in both AOCs showed that malformations had been reduced to rates that satisfied the restoration targets set by the State of Ohio to remove the BUI. This marks the fifth BUI removed from the Black River AOC with four remaining BUIs. This is the fourth BUI removed from the Cuyahoga River AOC with five BUIs remaining.