06/06/2015 12:20 EDT | Updated 06/06/2016 05:59 EDT

Demonstrators decry state of Rio's sewage-filled waters ahead of Olympics

RIO DE JANEIRO - Activists on Saturday staged a demonstration on a sewage- and trash-filled strewn Rio de Janeiro beach to protest authorities' failure to make good on promises to clean up the Olympic city's filthy waters ahead of the 2016 games.

Protesters gathered on Rio's Botafogo Beach, in the Guanabara Bay near where Olympic sailing events are to be held, and unfurled a banner reading "One billion dollars and it's still disgusting." A kayaker plied the brackish waters with a toilet atop his craft as the stench of sewage blew in on a gentle breeze.

With poor sanitation and garbage collection systems, much of the sewage and trash in this city of 12 million is swept into rivers that flow onto the city's famous beaches, lakes and lagoons, as well as Guanabara Bay. An initial effort to clean up the bay, dating back more than 20 years, failed to make much of a dent in the problem, and as part of the city's Olympic bid officials promised that a cleanup would be one of the games' most enduring legacies.

More than five years have passed since Rio was awarded the games, but the situation remains largely the same. And with just over one year left before the showcase sporting event, authorities have acknowledged their Olympic cleanup pledges won't be met, prompting Olympic sailors and others to voice worries about possible health risks to athletes who come in contact with the waters.

Rosemary Vega, a microbiologist who was taking part in Saturday's protests, said such fears were warranted. She pointed to a recent study showing the presence of drug-resistant "super bacteria" in the waters of Botafogo and the neighbouring Flamengo beaches.

"What people don't know is that these kinds of infections can kill you," she said. "It's a disgrace."