Care to take a dip at a local beach? Maybe you'll think twice as this bit of news warns us of something quite disturbing: U.S. beaches are polluted. That really isn't news to us, but it's the type of pollution that's a bit surprising. According to a group of experts from Johns Hopkins University, the beaches are polluted with pathogens from... er - poo.

International science magazine New Scientist reports of a recent study by public health expert Thaddeus Gracyzk and some of his colleagues. They tested water taken from Maryland's beaches twice a week for almost three months back in 2006. The water was tested for Cryptosporidium parvum and Giardia lamblia, a couple of protozoans found in human feces. Both of the said protozoans can cause severe gastrointestinal problems, some might even lead to death.

They found that 30% of samples taken during weekdays had pathogens while it shoots up to 60% on weekends. According to the study, the level changes are proportional to the "bathers in the water."

Where'd all the poo come from? According to Gracyzk, bathers can upset the sediment where the microbes rest - either coming from sewage or from surface run-off after heavy rains.