tons of garbage flow into the bay every day. he says raw sewage from 8 million people have turning some stretches of these tropical waters jet black. oceanographer david zee says in the water where sailors will compete researchers found samples of so-called super bacteria that s resisted to antibiotics. would you let your children swim in this watter? no, for sure not. you know, the water is not safe enough. reporter: according to an investigation by the associated press, a single virus reading in the lake tested up to 1.7 million times what s considered hazardous on a southern california beach. brazilian officials challenge that report s methodology. the international olympic committee also said world health experts found no significant risk to athletes. but neither the brazilian company or the ioc has tested for viruses, only bacteria.