Rio de Janeiro is an enormous metropolis, with more than 12 million inhabitants, and Guanabara Bay has served as the city’s cesspool and sewage dump for many years. Before the games, a large majority of the sewage generated in Rio was delivered untreated into the bay, along with considerable quantities of ordinary junk and garbage, and the bacterial and viral contamination level in the water were astronomically high. Local officials promised that they would take steps to increase the level of treatment so that 80% of the sewage entering the bay would go through a treatment plant, but it is thought that, at best, only 65% of the sewage is treated at the current writing.
Brazil made a number of promises about cleaning up the city when it won its bid to host the Games, but numerous reports indicate that the cleanup efforts fell well short of promises. Although reports from Olympic athletes indicate that the amount of visible debris and waste have been significantly reduced, it is thought that these have been mainly cosmetic measures. Data from water quality assessments backs up this pessimistic account; an Associated Press investigation done before the Games began showed viral levels 1.7 million times higher than what would be considered problematic in the United States.
The water in Guanabara Bay is contaminated, but how about the water along Rio’s famous beaches, some of which front the Atlantic Ocean? Unfortunately, the beaches may be even worse off than the deep water of the Bay. The beaches of Rio de Janeiro are connected to a criss-cross maze of canals and stormwater drains, which are in turn deeply contaminated with human waste. Most of the residents of the city’s favelas (slums) have no indoor plumbing and the minor waterways of the city are essentially communal sewers. As a result, the beaches always have high levels of coliform bacteria, a problem which worsens exponentially whenever one of Brazil’s torrential rains floods the drains and canals.
Although the water in Rio is dirty, experts do caution against apocalyptic rhetoric concerning the actual level of danger. The World Health Organization notes that the most likely outcome from ingestion of contaminated water is short-term gastroenteritis; not something anyone wants, but not a major life-threatening condition for people in good health otherwise. Olympic athletes are taking precautionary measures for their time in Rio, stocking up on antibacterial wipes and keeping water bottles inside of plastic bags to avoid splash contamination, for example. Some athletes expecting to swim in the most contaminated areas have received Hepatitis A vaccines as a prophylactic step. The athletes and tourists, however, will be going home in a few weeks. Those at most risk from Rio’s dark waters are the people who have been there all along, and it is they who are most in need of a sustained and meaningful effort to address the water pollution in Rio de Janeiro.