Okeechobee Mudfest, Florida, United States

In 2007, during a drought, state water and wildlife managers removed thousands of truckloads of toxic mud from the lake's floor, in an effort to restore the lake's natural sandy base and create clearer water and better habitat for wildlife. The mud contained elevated levels of arsenic and other pesticides. According to tests from the South Florida Water Management District, arsenic levels on the northern part of the lake bed were as much as four times the limit for residential land. Independent tests found the mud too polluted for use on agricultural or commercial lands, and therefore difficult to dispose of on land.
Through early 2008, the lake remained well below normal levels, with large portions of the lake bed exposed above the water line. During this time, portions of the lake bed, covered in organic matter, dried out and caught fire. In late August 2008, Tropical Storm Fay inundated Florida with record amounts of rain. Lake Okeechobee received almost a 4-foot increase in water level, including local run-off from the tributaries. This quick rise, mixed with largely polluted run-off from local farmlands, has killed thousands of fish.