Nevada County health officials continue to investigate a “plume” of contamination on the South Yuba River that tested positive for E. coli bacteria last month, now saying that a property previously identified as a possible source of the pollution does not appear to be connected to the incident.
Authorities had declared a no-swim advisory for a stretch of the river, as well as Englebright Lake, after discolored water near the Highway 49 bridge tested positive for “dangerous” levels of E. coli and unknown sediments on Sept. 20.
The advisory was lifted the following week, and on Sept. 25, Nevada County said in a news release that its investigation had centered on a property in the 13000 block of Kilham Mine Road in Nevada City.
Investigators identified the property after a helicopter flyover and found code violations at the site.
But Nevada County Office of Emergency Services in a news release Wednesday evening said that county code compliance “does not currently believe that the alleged violations are connected to the plume,” also noting that the property owner has been cooperative with the investigation.
“It does not appear that cannabis cultivation or active mining on the Kilham Road property was the cause at this time,” Sean Powers, the county’s community development agency director, said in a statement.
A “complex” investigation is continuing, Powers said, with parcels adjacent to the Kilham Mine Road property also being looked at, including land owned by the Bureau of Land Management.
County health officials also received new test results this week confirming that the South Yuba River and Englebright reservoir are safe for recreational use after test results from eight sample sights showed no toxic metals or high E. coli levels, the news release said.
E. coli bacteria is usually indicative of fecal contamination.
“The investigation is a formal process and will take time,” Wednesday’s news release continued. “Weekly updates will continue to be posted at MyNevadaCounty.com/YubaRiverAdvisory as more information becomes available.”