City officials have determined that a mysterious sheen on the Ohio River two weeks ago was not caused by a chemical spill. But though they’ve ruled that out, the evidence is inconclusive.
The Metropolitan Sewer District sent several of the Asian Carp that were found dead in the river out for tissue analysis. And according to MSD Regulatory Services Director Brian Bingham, they found….nothing.
“We had a number of tests performed on some of the fish we found that were dead in the area and of all the tests we had run, none of them came back with any chemicals or any metals or any cause of their deaths,” he said.
Bingham says if the fish had been killed by a chemical spill, it would have shown up in the tissue sample. The lack of evidence suggests the fish were killed either by a sudden temperature change or a lack of oxygen, which could have been caused by an algae bloom. Algae blooms are fed by nutrients, like pollution.
“Algae blooms occur all the time in the Ohio,” Bingham said. “Algae blooms that actually kill fish are fairly rare. From our experience, they usually occur during the hotter, dryer periods of time. So it’s a combination of the temperature change and the algae bloom that depletes the oxygen.”
The MSD has closed its investigation into the incident, but Bingham says if any more dead fish are found, the agency may analyze water samples.