FRIDAY, Aug. 31, 2012 (HealthDay News) -- The beaches along Lake Erie, where many people swim each summer, contain high concentrations of bacteria that are a sign of human fecal contamination, a new study shows.
The bacterium, known as Arcobacter, causes diarrhea, and those most vulnerable to infection are young children, the elderly and people with weakened immune systems, said study author Jiyoung Lee, an assistant professor at Ohio State University.
The study was published in the August issue of Applied and Environmental Microbiology.
The beaches studied in the analysis are all part of the Ohio state park system. Two are urban beaches that attract more than 9 million annual visitors, and the other two are natural sand beaches with more than 4 million visitors, according to study background information.
From those beaches, 75 percent of the 129 water samples taken in the summer of 2010 were positive for Arcobacter.
It's not known from the study whether other Great Lakes have similar levels of contamination.
"Lake Erie is the smallest and warmest compared to other Great Lakes, and it's shallower," Lee noted. "So [bacteria levels] could be similar but, for these and other reasons, might be different."
In June, the Natural Resources Defense Council (NRDC) released its annual report on beach closings and official beach advisories. Last year, 11 percent of Great Lakes samples violated public health standards.
Karen Hobbs, senior policy analyst for NRDC's water program, said the new Arcobacter results "track along with the findings in our study. So, it was certainly no surprise that fecal coliform is being found in beaches in Ohio."
"Across the Great Lakes, we have a problem with our aging and failing infrastructure," Hobbs added. "So, we have water main breaks, we have sewage pipes that leak, we have illegal connections. We still have a problem with folks directly discharging into the lake."
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," Hobbs said.
Lee added that "animals can contribute significantly to fecal contamination. If you bring your dog to the beach, make sure it doesn't contaminate the beach near the water." And, "parents with young children in diapers should be cautious that there's no leakage," she said.
In addition, local ordinances should ensure that nearby property owners maintain their septic tanks, Lee pointed out.
At the government level, Hobbs said, "The EPA must reconsider those proposed criteria and make sure they're using the latest science, and that they're covering the range of illnesses that we know can arise from swimming in contaminated water."
Visit the U.S. Environmental Protection Agency for information on beaches.