Poop on the Beach

Health inspectors usually test beach waters during the week. "The water should be tested when the numbers of people are higher," says Graczyk. "A lot of beaches would be closed if they tested on weekends." Gracyzk suspects bathers stir up sediment that already contains the microbes, which enter recreational waters primarily through human faeces, either directly, through sewage or from surface run-off after heavy rains. He will present his findings next month in Philadelphia at the American Society of Tropical Medicine and Hygiene meeting.