The Ohio River, already the most polluted river in the United States, oozes with a toxic new menace: a spreading carpet of algae that poisons wildlife, thwarts recreation and threatens the water supply of 3 million Americans.
Algae has clogged the Ohio before, but never like this. It currently floats on nearly two-thirds of the iconic river that originates in Pittsburgh and meanders 981 miles through six states. The outbreak — euphemistically called a “bloom” — currently affects 636 miles of the river, from Wheeling, W.Va., to Cannelton, Ind.
The blue-green algae has a formal name: microcystis. It is bacteria fed by phosphates and nitrates, byproducts of sewage, manure and fertilizer washed into the river. Ingested, it can kill animals and cause diarrhea, vomiting and liver damage in humans. It was an algae bloom like this in Lake Erie that forced residents of Toledo, Ohio, to use bottled water for three weeks in August 2014.
So far, no drinking water has been affected by the unprecedented spread of the algae, but some cities have told people to stay away from the river, causing the cancellation of several athletic events involving boating and swimming.
Bad as it is, the river is still not as toxic as it was a half-century ago, when sewage and industrial waste was routinely dumped in the water. And it needs hot temperatures and strong sun to flourish, so with autumn upon us, it’s likely the algae won’t spread to Pittsburgh, and thus to the Allegheny and the Mon.
But the bloom reminds the 25 million people — 10 percent of the U.S. population — who live in the Ohio River Basin just how important a resource the river is. With temperatures rising and rainfall increasing in the region over the past three decades, microcystis could become an annual threat, and its alarming spread shows that current regulations regarding runoff from factories and farms aren’t strict enough.