SACRAMENTO, Calif. — A new report released Friday by the California Water Board reveals that birds and dogs are still suspected to be the largest polluters of the American River through Sacramento.
The study conducted by the state's Water Board investigated levels of bacteria and fecal pollution in the lower six miles of the American River from Sutter's Landing Regional Park to the confluence of the Sacramento River.
During 13 events in 2021, samples of the American River were collected from 12 monitoring stations, six of which had shown levels of E. coli exceeding the water quality objectives for more than half of the time of the study.
Those six locations with high levels of E. coli included areas around Tiscornia Park, the Jibboom Street Bridge, Discovery Park, 5th Street, 10th Street and Camp Pollock.
According to the study, samples of the elevated levels of E. coli were submitted for microbial source tracking, a process meant to analyze the water sample to determine the source of fecal contamination.
Birds were determined to be responsible for almost 50% of cases where E. coli levels were found to be elevated, the study shows.
The second largest group contaminating the American River was said to be dogs, representing nearly 30% of all cases where E. coli levels were high.
According to the study, humans were neither a significant nor consistent source of fecal contamination in the American River in 2021.
The study's results reinforce previous findings, including another Water Board study released in December, which held that humans were not significant sources of contamination in the American River.
In the fall, researchers say they expect to release an analysis of more data as the second phase of the Lower American River Bacteria Study will be completed.
The second phase has included 30 sampling events along the American River over the course of two summers.
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