CHICAGO — University of Illinois at Chicago researchers and park district officials say they’ve come up with a way to keep swimmers out of Chicago’s lakefront when there is too much bacteria.

For decades, public health experts and park officials have struggled to decide when to shutter beaches to protect swimmers from illness-causing bacteria, such as E. coli, the Chicago Sun-Times reported .

A team at the university conducted same-day tests of the water this summer. The effort has allowed the park district to post alerts based on 4-hour-old data.

Testing used to take up to 24 hours, meaning lifeguards advised people about the water based on conditions from the day before.

“It’s not that the old (culture) test wasn’t giving us accurate results, it just turned out that they weren’t as useful,” said Cathy Breitenbach, the park district’s director of cultural and natural resources.

Dr. Samuel Dorevitch, a public health professor leading the team of researchers who conduct the daily testing, said water samples are taken from 20 locations on the lakefront at 8 a.m. and that test results are completed by noon.

“Everybody else reports to the public what water quality was yesterday, because they use the old culture procedure,” he said.

Bacteria counts of 1,000 “Calibrator Cell Equivalents” trigger an advisory. The Park District has posted advisories for high bacteria 180 times at 26 beaches so far this summer.

Researcher Abhilasha Shrestha said North Avenue beach is the only beach that hasn’t had an advisory day. Humboldt Park’s artificial beach, which has had 38 advisory days since the city’s parks and pools opened on Memorial Day, has had the most frequent high bacteria counts.

Shrestha said a bacterium in the lake can come from feces from seagulls, dogs or babies. Heavy rains causing runoff into the lake also contribute to high bacteria.

National Resources Defense Fund officials say they hope Chicago’s program will be a model for other cities with waterfronts.

“Timely information is important for making sure that a day at the beach is really a day at the beach, and not something really unpleasant,” said Joshua Mogerman, a spokesman for the organization.


Information from: Chicago Sun-Times, http://chicago.suntimes.com/

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