ERIE, Pa. (AP) -- Two beaches at Presque Isle State Park have again been closed because of high E. coli levels, leaving officials puzzled about the cause.
Beaches 1 and 9 were closed Friday afternoon. Beaches must have counts below 235 "colony-forming units" of the bacteria per 100 milliliters of water to be open for swimming.
Beach 1 had an average of 427 units, and Beach 9 had an average of 507 units of E. coli, a type of bacteria commonly found in fecal matter. Each beach is tested three times at different locations and the results are averaged.
All but two of the nine beaches were closed earlier last week because of high levels. One beach reopened Tuesday, and the rest reopened Thursday.
Officials had blamed heavy rains last weekend and above-normal water temperatures for the high bacteria levels but were at a loss to explain the jump at just two beaches.
"Why they would zoom up again in a day, I just don't know," said Dave Rutkowski, assistant park manager. "It's just nature."
About 4 million people visit the park annually.