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CA study: American River pollution caused by dogs, birds

Bird and dog feces — not human waste — are the main sources of E. coli found in the stretch of the American River below Sacramento’s sprawling riverside homeless encampments.

On Friday, state scientists released those initial findings as part of their years-long DNA study that seeks to answer the controversial question that’s hounded the region for years: Whose poop is causing the dangerous spikes in E. coli fecal bacteria at popular swimming areas near downtown?

The findings released by the State Water Resources Control Board on Friday seemed unlikely to settle the debate.

Homeless advocates said the findings proved that the campers were unfairly blamed for water contamination in the Lower American River. Parkway advocates said the findings don’t answer why huge spikes in E. coli keep happening along the river below the homeless camps, putting swimmers at risk.

Friday’s report, however, could factor into an ongoing discussion about whether to keep temporary portable toilets for those living illegally at the more than 200 homeless camps that line the riverbanks. For years, county officials have resisted doing so, saying the homeless people just destroy them. County spokeswoman Kim Nava said the county had only just seen the report Friday afternoon and would need time to review it before commenting.

The state water board scientists last year took bacterial samples from the three-mile stretch of the American River from Sutter’s Landing Regional Park to the confluence with the Sacramento River. The researchers then did what’s known as “microbial source tracking analysis” that was able to differentiate genetic markers for humans, dogs and birds as sources of fecal contamination.

Their samples were taken from sites where E. coli levels were unsafe for swimmers, including at the popular Tiscornia Beach swimming area. Tiscornia has long been a hotspot for E. coli contamination.

The results suggest it wasn’t necessarily human feces causing those spikes.

“Results indicate that birds are the largest and most consistent source of fecal contamination,” the report’s authors wrote. “Dogs are also a consistent source of fecal contamination in some areas. Humans were not a significant or consistent source of fecal contamination during the 2021 sampling period.”

There are dozens of Canada geese and other water birds that gather daily at Tiscornia Beach and further upriver. A single goose can produce up to three pounds of feces per day, by some estimates.

Many of the people living in the camps along the river have dogs, and hundreds of others bring their dogs down to the river to play and swim.

Friday’s report was the second phase of the state’s ongoing E. coli sampling. Last fall, the water board released its initial findings along the upper stretch of the Lower American below Nimbus Dam. It found similar results. Fewer homeless people live along that stretch of river.

Toilets for parkway campers?

The results of the study were seen as a victory for homeless advocates.

The findings will refute the blame some politicians have placed on homeless individuals in recent years that they are polluting the so-called “crown jewel of Sacramento,” said Zoe Kipping, an activist with Sacramento Solidarity with Unhoused People.

“It’s affirming to know that it’s mostly hype and stigma that people who don’t have housing that live along the American River are responsible for bacteria in the river,” Kipping said. “Bacteria is just part of the ecosystem.”

Parkway advocates had long pointed to the encampments as a source of the contamination. Robert Metcalf, a retired Sacramento State microbiology professor who studies water contamination, wasn’t ready to give up that position on Friday. He said the findings raised more questions.

Metcalf has been leading efforts to independently sample for E. coli at swimming sites such as Tiscornia.

He said he’s not surprised to see bird feces being high in the samples the state scientists took, but he said that it doesn’t account for the massive spikes in E. coli that his team of volunteers find.

“There’s goose poop all the way around there all the time, and we get low counts a lot of the time,” Metcalf said. “But then what are the high counts (at those same locations)? What are the spikes that exceed—way exceed—the EPA recommendations?”

Anywhere from 200 to 300 homeless people regularly camp upstream from Tiscornia Beach, and, as a 2019 Sacramento Bee investigation found, it’s not hard to find used toilet paper and human feces lining the rivers’ banks around the camps. It’s illegal to camp in the parkway, but homeless people have lived there for years.

Even if their feces isn’t going into the river, fecal contamination associated with homeless encampments comes with substantial health risks for people recreating in the area and for the campers themselves.

In recent years, cities in California and elsewhere have been seeing spikes in hepatitis A and typhoid fever, both spread by human feces. The outbreaks were linked at least in part to poor sanitation around homeless camps.

It was only during the COVID-19 pandemic that county officials who run the American River Parkway began putting toilets out for campers.

As of February, Sacramento County had 37 portable toilets along the parkway for the homeless, but they could be removed later this month.

Kipping the homeless advocate, urged the county to leave the toilets there, and add more.

She said most homeless people on the river do not want to be there, but are left with no choice after police sweep them from city streets and parks.

E. coli study to continue

State and local officials have long been reluctant to cite a particular source of fecal contamination as a cause of the E. coli in the water.

Instead, the Central Valley Water Board, Sacramento Regional County Sanitation District, Sacramento Area Sewer District, Sacramento Stormwater Quality Partnership and Sacramento County Regional Parks teamed up to conduct a multi-year study sampling the DNA of the E. coli in the Lower American.

The cost to taxpayers for the study that will continue through this fall: $600,000 to $800,000.

Parkway advocates such as Metcalf have criticized health officials for not closing swimming beaches despite having high E. coli readings.

County officials have said they’ve not seen any spikes in illnesses associated with the contamination. They do post results of the state’s E. coli tests on the county’s website and have installed permanent signs along the parkway’s river access points to warn swimmers to avoid drinking the water and to wash their hands and shower after getting wet.

Most E. coli strains found in human and animal intestines are harmless. Not every strain of E. coli bacteria causes potentially lethal symptoms such as bloody diarrhea, which would trigger a notification to county health officials.

Usually, the symptoms the bacteria would cause, such as diarrhea, clear up without a doctor’s visit, so the health department would likely never know if someone fell ill from swimming in the American.

This story was originally published June 4, 2022 5:00 AM.

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Ryan Sabalow covers environment, enterprise and investigative stories for McClatchy’s California newspapers. Before joining The Sacramento Bee in 2015, he was a reporter at the Auburn Journal, the Redding Record Searchlight and the Indianapolis Star.


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