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City Says Ohio River Fish Kill Wasn’t Caused by Chemical Spill

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.

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Environment Local News

Algae Bloom May Be Cause of Ohio River Fish Kill

The head of the Metropolitan Sewer District says the fish kill on the Ohio River last night may have resulted from an algae bloom, rather than a chemical spill as was previously reported.

The sheen on the Ohio River was noticed south of Rubbertown by cameras at Dow Chemical’s plant, and about 20 Asian Carp were found dead. It was initially thought to be a chemical release from somewhere upriver, but water sampling by three separate entities was negative.

Now, MSD Executive Director Bud Schardein says the culprit could actually be an algae bloom, which suffocated the fish.

“We get warm weather temperatures for several days and the algae starts growing from the nutrients in the water,” he said. “And then usually after you have a rain event—and we had about an inch and a half or two inches of rain yesterday—these blooms turn over and any fish that are around them usually suffocate for lack of oxygen in the water.”

But the weather isn’t the only cause– excess pollution and nutrients can also cause a bloom.

“We use a lot of fertilizers,” Schardein said. “I know we talk about the dead zone in the Gulf of Mexico, and that’s just basically the result of nutrients that have washed downstream. And along the way, once they’ve warmed up sufficiently with water temperature, they start creating algae.”

MSD won’t know for sure if algae is to blame until the fish tissue is tested, and results should be ready in a few days.