Storm water runoff is a big problem, Hobbs said, from rainwater that washes over roads and fields, picking up contaminants from oil, horse manure and other sources along the way.
The U.S. Environmental Protection Agency bases its recreational water quality criteria on E. coli and enterococcus bacteria concentrations, and that's what state and local governments use to determine when to close beaches or post advisories.
Because Arcobacter is an emerging bacterium -- first discovered in 1991 -- it's less familiar than E. coli. But in the new study, the presence of Arcobacter was an earlier predictor of fecal contamination. "Arcobacter could be a good candidate for inclusion for EPA monitoring," Lee said.
The EPA is in the midst of revising it standards for recreational water quality and has released a draft of the proposed 2012 criteria. Those criteria fall short, the NRDC says.
"The way that they've currently proposed those standards, it would allow about one in 28 swimmers to become ill with gastroenteritis, from swimming in water that just meets the proposed water quality criteria," Hobbs said.
Arcobacter monitoring "is one of the many things that should be included," she said.
Would these experts in water quality swim in a freshwater lake?
"Personally, I prefer to swim in seawater," Lee said.
As for Hobbs: "I love to go to the beach. I just try to be a much more informed consumer of the beach water these days."
People can enjoy the beach while taking precautions.
"I usually wash my hands and face after I swim," Lee said. "The face is important: eyes, nose, ears, mouth are all openings. If you can take a shower after swimming, that's perfect."
Both advised staying out of the water after a heavy storm.
"I always make sure I check before I go whether there's a closing or advisory day,"
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