Swimmers who enjoy Chicago-area beaches along Lake Michigan and numerous inland lakes may be exposed to potentially harmful levels of bacteria for hours or days before officials take action, according to an NBC 5 Investigates analysis of beach-monitoring data from Illinois, Indiana and Wisconsin.
Storm water, sewage and animal waste leave behind much of the E .coli in beach water that can cause swimmers to become ill. The U.S. Environmental Protection Agency and state health departments require cities to issue swim advisories when bacteria levels reach 235 cfu/100 ml or above. Swim bans are required when levels reach 1000 cfu/100 ml or above.
NBC 5 Investigates found 218 cases in 2013 when E. coli levels were so high, cities were supposed to require complete swim bans. But in 104 of those instances, people were allowed to swim in highly-contaminated water for a full day or more, before any advisory or ban was issued.
According to local park districts, the testing procedure can be "frustrating." It takes about 18 hours for beach water test results to be completed in a lab.
"Testing water on one day and then closing the beach the following day because it's exceeded bacterial standards isn't fully protective of public health and safety," said Karen Hobbs of the National Resources Defense Council, a non-profit, environmental advocacy group.
Indiana beach-monitoring records show Whihala Beach in Whiting had nearly seven times the E. coli level dangerous enough to trigger a swim ban on July 17, 2013. However, records reveal officials took no action until the next day. The city official in charge of beach-monitoring in Whiting could not be reached for comment.
"We have some concerns about the strictness of the criteria, but we're mostly concerned with how beach managers are using that data," Hobbs said.
For most inland lakes, NBC5 found that bacteria levels are measured only two times a month - the minimum required under state standards -- meaning those swimmers have almost no information on how clean their water is.
Many beaches along Lake Michigan, however, are monitored every day. That means officials can take action more often.
The following beaches each recorded ten swim advisories or bans in 2013, according to Illinois monitoring data: Gillson Park in Wilmette on Chicago's North Shore; 57th Street in Chicago; Oakwood in Chicago; 31st Street in Chicago, and Calumet South in Chicago.
Based on recent years' statistics, the Chicago Park District is seeing a decrease in the number of advisories and bans at many of its popular beaches.
"We've worked really hard to keep the beaches clean and safe for the public and we are seeing some good results," said Cathy Breitenbach of the Chicago Park District.
The Chicago Park District received a grant from the U.S. EPA in 2010 for $245,420.00. The money supported the purchase of monitoring equipment, data collection and statistical work to develop models that predict when bacteria levels in beach water would be high enough to issue a swim advisory or ban, thus preventing swimmers from wading in contaminated water. The city now spends about $20,000 a year to maintain and operate its predictive modeling system.
Chicago is also going to the dogs, literally, to help keep several of its beaches clean. The park district hires specially-trained border collies to scare away gulls and the bacteria they leave in or near water. Advisories at 63rd Street Beach in Chicago have been cut dramatically over the past few years with the help of the dogs.
"As long as the dogs are out there stalking the birds, they tend to stay away from the beach," said Carla Wagner of Wild Goose Chase, Inc.
The National Resources Defense Council urges swimmers to use good beach-goer etiquette: Don't feed wildlife; don't litter, and place infants and toddlers in waterproof diapers.