Planning to visit the lower American River this holiday weekend? Potentially harmful levels of bacteria lurk in certain stretches, authorities warned Tuesday.
Boaters, swimmers, kayakers and others can still enjoy the river on the Fourth of July and into the weekend, county officials said. But they urged using "common sense" precautions because certain stretches of the waterway are contaminated with potentially harmful levels of E. coli bacteria.
The latest tests of water samples near Tiscornia Beach, Discovery Park, Sutter's Landing Park and Steelhead Creek revealed E. coli levels that are higher than the standard set by the Environmental Protection Agency, said Adam Laputz, assistant executive director of the Central Valley Regional Water Quality Control Board.
Laputz recommended that visitors check the latest E. coli levels on an online map, or by following CA Water Boards on Twitter.
Along the Lower American River, the highest E. coli level was recorded this week at Sutter's Landing, well above the federal standard, according to the map. But just downstream, Camp Pollock had levels that met EPA criteria.
The board has been testing water samples weekly along the river this summer in an effort to pinpoint problem areas, look for pathogens and determine the sources of contamination. Sources likely include human waste from homeless camps, sewer overflows, wildlife and domestic dogs, Laputz said.
County health officials said they are unaware of any cases of illnesses related to the water's contamination, but said visitors should be cautious. Anyone who suffers gastrointestinal illness after spending time in the river should contact their physician, they said.
E. coli is a "naturally occurring" bacteria, and most strains of it are harmless, said Laputz. But some contain dangerous pathogens that can sicken humans, such as giardia, salmonella and Hepatitis A.
The county is not advising against visiting any part of the river, said spokeswoman Kim Nava. The health risk in the American is "no different than in any public waterway," she said.
"We're telling people, if you want to recreate on the water, please do. Just use common sense."
Visitors should never drink river water, or cook or wash dishes in it, the county advises. Visitors should never change diapers in or near the water, swim when they are feeling ill or enter the water with cuts or open sores.
The county has posted "healthy swimming habits" signs at various locations along the river, Nava said.
"The river is not necessarily unsafe," she said. "Really, if we're talking about avoiding danger, the best piece of advice is to use a life vest" to prevent drowning.
Laputz said the board's research of contaminants along the river is in its early stages and has yet to pinpoint the sources of contamination. The most problematic sections of the waterway have high concentrations of homeless camps, he said. Levels also may rise after rainstorms. Warmer weather may also cause E. coli to spike.
"We've not identified a trend at this point," Laputz said..
DNA studies and other research will help determine the sources and risks of the E. coli, he said. That could take a year or more.
The results will help county health officials better gauge the level or risk for people who use the river for recreational activities. It also will help authorities figure out ways to reduce bacteria levels in the waterway, said Laputz.
Until then, "people need to pay attention to safe habits," including showering after spending time in the river and picking up after pets.
"This is a large watershed, and little things like this can make a big difference in the long run," Laputz said.