With beach season underway, it’ll take just hours for the Chicago Park District to measure the amount of bacteria in the water at five of the city’s 27 beaches.
It’s part of a pilot program at the Calumet, Rainbow, South Shore, 63rd Street and Montrose beaches. The new method, part of a partnership with the University of Illinois at Chicago, will help the park district more quickly determine whether E. coli is present in a water sample.
The park district will find the water’s bacteria level within a few hours instead of the next day.
Typically, employees collect water samples at all 27 of the city’s beaches about 8 a.m. With the new partnership, the samples at the five beaches selected for the pilot program will be taken to a UIC lab to use the new technique. The park district will continue to conduct the test they’ve used for years, which determines whether E. coli is in the water.
“The test that we have been using historically takes a day to get results back, and so that was frustrating because we would be telling what the water quality was like yesterday,” said Cathy Breitenbach, director of natural resources for the park district. “We’re adding a new layer because the science is finally here now and we’re able to use a new test that will give us results in a few hours.”
The new method counts DNA fragments, while the old method involved culturing bacteria cells.
“We’ll hear by early afternoon now,” Breitenbach said. “It’s faster results and we’re happy now that the science is there so we can tell people more about the risks.”
Swim advisories at Chicago’s beaches are issued when test results show bacteria counts to be higher than 235 colony forming units per 100 milliliters of water, an EPA standard which is used by all Great Lakes beach managers. That means there is a 75 percent chance that at least eight out of 1,000 people will develop gastroenteritis. A swim ban is issued only for hazards like sewage spills or weather conditions.
The park district uses a flag notification system and Web page to display swim status, water quality and weather data. Green means swimming is permitted; yellow means it’s permitted but caution is advised because of weather conditions or bacteria levels; and red means swimming isn’t permitted because of dangerous weather conditions.
Although beaches opened for the season Friday, it’s still a bit nippy. Breitenbach said the water temperature is about 52 degrees, which is normal for this time of the year.
Seagull waste remains a chief cause of bacteria in the water. The park district does its best to clean up trash on the beach, which prevents some seagull waste.
It’s also continuing a program the district has used for years at some beaches, including at the 57th and 63rd street beaches.
“We use trained border collies — their handlers are wildlife biologists — that chase the seagulls off and it’s made a huge difference,” Breitenbach said. “We’ve seen a dramatic improvement in the water quality. It’s really well-justified.”
But the problems aren’t the same at every beach. Inclement weather can turn up bacteria, and rainfall can bring in animal waste.
“When it rains it ends up washing things into the lake,” she said.
The park district is also issuing a friendly reminder: Don’t leave behind dirty diapers — and clean up after yourself.
“People just don’t realize, it does make a difference if you take care of the beach,” Breitenbach said. “It’s fine to come and have a picnic, but when you’re done, take care of your waste and throw it away.”
Chicago’s beaches are open between 11 a.m. and 7 p.m. daily until Labor Day. Outdoor pools will open June 12.
