Swimmers and waders beware: there may be something unexpected in the water.

North Carolina's streams are filled with hog excrement that leaches into them from the state's factory farms, according to a study published last month. The researchers found that 23 percent - nearly a quarter - of the samples exceeded state and federal recreational water quality guidelines for fecal bacteria and E. coli, strains of which can cause severe health problems for humans. Unsurprisingly, the most bacteria was found in waters immediately downstream of large hog facilities.

(Flickr/y'amal)