• In this April 28, 2015 photo, Fernando Spilki, virologist and coordinator of the environmental quality program at Feevale University, holds up a water sample, backdropped by the Marina da Gloria, Zone 2, in Rio de Janeiro, Brazil. Spilki said the tests he conducted for the Associated Press so far show that Rio's waters "are chronically contaminated." (AP Photo/Felipe Dana)

    AP Investigation: What’s in Rio’s water? AP explains tests

    RIO DE JANEIRO (AP) — Sewage pollution has long been a problem for Rio de Janeiro, and officials promised they would use the 2016 Summer Olympics as the springboard to finally clean up this stunningly beautiful city’s waterways.