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SACRAMENTO, Calif. (KTXL) — At the lower American River, colder temperatures aren’t the only reason why some are avoiding taking a dip.

“Everybody tells us not to swim in there,” said Jeuel Rodriguez, who was visiting the river.

Over several years, part of the American River was found to contain high levels of E. coli bacteria, most recently in the Tiscornia Park beach area.

Many visiting along the river point to one thing.

“I feel like it is the homeless people because there are a lot of homeless people here and there are no bathrooms,” Trinity Eads said, who was visiting the river for the first time.

William Hardy has lived in Sacramento his entire life and said, this year, human activity has gotten even worse.

“Definitely the last five or six years it has even gotten worse,” Hardy said. “There has always been equally amount of wildlife as there is today, so it’s not the wildlife.”

But a DNA testing project from the Central Valley Regional Water Quality Control Board shows the main source of E. coli contamination in the river are from birds and dogs — with only a small amount coming from humans.

The samples for the testing were taken along a 3 mile stretch of the American River, starting at Sutter’s Landing Regional Park all the way up to Paradise Beach, near Cal Expo.

While public perception may have suggested that humans were a leading cause of E. coli in the river, the DNA results for the Paradise Beach to Sutter’s Landing section of the river so far show otherwise.

Alisha Wenzel – Engineering Geologist, Central Valley Regional Water Quality Control Board

It’s a result Hardy finds difficult to accept.

“I disagree with it,” Hardy said. “I think it’s from all the homeless out here and humans — too many people.”

While most E. coli can be harmless, it can lead to other infections.

This was the first part of the American River bacteria study, with samples taken during the summers of 2019 and 2020. The second part will focus on Sutter’s Landing to the confluence, where the lower American River empties into the Sacramento River, near discovery park.

That report could be released in the spring of 2022.

Read the full release here: