Illinois ranks third among the five states with the highest frequency of contaminated beaches last year, according to an annual report released Tuesday from the Natural Resources Defense Council.
Water samples at the state’s most popular beaches fell short of national standards 15 percent of the time, the report found. It also cited Jackson Park Beach at 63rd Street in Chicago as the fourth most polluted beach in the nation, with samples found to be contaminated more than half of the time.
The study, based on data from the federal Environmental Protection Agency, also found Illinois beaches saw 591 closings and advisory days last year, a slight increase from 2005.
This summer, however, beach closings in Chicago are down from the previous year, city officials said.
There have been 47 swim bans at Chicago beaches since Memorial Day, compared with 62 closings during the same period last year. The number of advisory alerts, which feature a yellow flag to indicate a higher risk of illness from E. coli, fell from 162 last year to 141 this year.
The new figures reverse a trend seen earlier this summer, as officials reported in early July that there had been more swim bans called by that time than last year.
Chicago’s beach closings are influenced by several factors, including the weather and the presence of animal waste, said Michele Jones, a Park District spokeswoman.
The 63rd Street beach consistently has a high swim-ban frequency, along with Foster Avenue Beach on the North Side, said Ellen Sargent, the city’s deputy director of natural resources. The city continues to investigate the higher E. coli readings there, she said.
