GASTON-LINCOLN COUNTIES, N.C. (QUEEN CITY NEWS) — The South Fork Catawba River is about to become more popular.

“Now that it’s summertime and he’s a school teacher, we will be down here probably every day or every other day,” said Tracy Donnelly.

And the river is not just popular with humans; Tracy and Patrick Donnelly often bring their dogs to play.

They didn’t know until Queen City News told them that the part of the river around the Laboratory Mill in Lincoln County is under a ‘no swim advisory.’

“If it’s something mysterious, I think the residents should know about it; I would have never taken him down to the water’s edge and let him play in it because that just doesn’t make sense,” said Tracy Donnelly.

The mystery is no more.

On Tuesday, people saw a foamy substance on the river and contacted authorities.

By Wednesday, they had an answer. It’s cow manure from a broken pipe, killing several hundred fish.

Authorities said the foamy, white material was observed floating in the river this week and caused concern among area residents.

A local dairy farmer recently discovered that a tree fell during a storm a few weeks ago and broke pipes that had pumped cow manure from a lagoon to various fields.

“I know that sounds like a lot of fish, but over five miles, that’s not a tremendous amount,” said Mark Howell with Lincoln County Emergency Management. “But it’s still a concern.”

Hazmat crews tested the water on Tuesday, and no chemicals were found. The cow manure is believed to have originated in Indian Creek and then flowed into the South Fork Catawba River.

“It was a significant amount of foam which was unusual, which would indicate something in the water that shouldn’t be there,” Howell said.

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According to Gaston County, water tests have ruled that the water is now safe for recreational use, and drinking water remains safe. The South Carolina Department of Health & Environmental Control says they expect no impacts in South Carolina but will continue their regular tests.

Gaston County Emergency Management, Gastonia Fire Department’s hazardous materials team, and Lincoln County Emergency Management are all involved in this investigation.

The cause of this incident has been determined as accidental. The North Carolina Department of Environmental Quality continues to investigate.