Ten percent of water samples at California beaches last year contained more human fecal bacteria than the state allows, according to a study released today by the Natural Resources Defense Council.
Violations of daily maximum bacterial standards at 227 California beaches increased 4% from 2007 to 2008, the study found.
"Many Californians were sickened or became ill after going to polluted beaches last year," Michelle Mehta, an attorney with the council's water program, said in a written statement. "The problem of beach water pollution has not improved and millions of people visiting California's world-renowned beaches continue to be at risk."
Although California may be famous for its surfing and swimming, the state ranked among the worst in beach water quality nationwide, coming in 22nd out of 30 coastal states. Los Angeles County was home to the most polluted beach water, with 20% of samples exceeding state standards.
In May, Heal the Bay also ranked Los Angeles beaches as worst in the state for water quality.
Bacteria can flow into beach water from sewage accidents such as the spill that forced closures in Long Beach on Monday. Storm water flowing through urban areas can also pick up animal waste, fertilizer, motor oil and other contaminants that are dumped into the ocean.
"We've described it as a toxic soup," Mehta said in a telephone interview Tuesday.
Although researchers linked 9% of contamination to sewage and 3% to storm water, the vast majority (81%) came from unknown sources.
The gap in knowledge underscores a need for better research, Mehta said.
High bacteria levels caused more than 20,000 beach closures and advisories nationwide and more than 4,000 in California. But local authorities sometimes don't have the financial resources to adequately monitor bacteria or to warn the public, according to Jessica Lass, a spokeswoman for council.
Scientists awarded five-star ratings to popular beaches that warned beachgoers and had relatively low levels of contamination. Among the highest-ranked beaches were certain locations at Laguna Beach, Bolsa Chica State Beach and Newport Beach.
The full report, Testing the Waters: A Guide to Water Quality at Vacation Beaches, will be available online today.
"The positive to take away is that there's good beaches next to bad beaches, so people can make a decision about what beach they go to," Mehta said.