By Kelley Lindsey

As the U.S. EPA updates 25-year-old recreational water safety standards, the Natural Resources Defense Council's (NRDC) recent water quality analysis reveals that 2011 beach closings and advisories fell 3% from 2010, even though 2% more sites were monitored.

More than 66% of 2011's 23,481 closings and advisories were due to bacteria levels too high for public health standards. Stormwater was the largest known cause of pollution, accounting for 47% of advisory and closing days; but 49% of reports cited “unknown” pollution sources. EPA estimates 10 trillion gallons of untreated stormwater contaminate surface waters annually.

Only 6% of advisories/closures involved sewage spills and overflows.

Researchers in Wisconsin and California tried a sampling method that would let water officials issue quality notifications the same day instead of waiting 24 hours for lab analysis. Quantitative polymerase chain reaction (qP-CR) measures E. coli DNA in water and returns results within 3 hours.

In October, EPA is expected to issue updated standards. Based on its new definition of gastrointestinal illness, water that now sickens 8 out of 1,000 swimmers would sicken 36 out of 1,000 swimmers — a 350% increase.