A stout green catamaran plied the polluted waters of Rio de Janeiro’s Guanabara Bay alongside wooden fishing boats, but its catch on Monday consisted not of grouper or swordfish but rather plastic bags, empty soda bottles and a discarded toilet seat.
The catamaran is one of three so-called “eco-boats,” floating garbage vessels that are a key part of authorities’ pledge to clean up Rio’s Guanabara Bay before it and other Rio waterways host events during the 2016 Olympic Games.
But critics say the boats do little to address the more pressing question of sewage.
With limited rubbish and sewage services in this sprawling metropolis of 6 million people, tons of garbage and raw waste flow daily from sludge-filled rivers into the bay, where Olympic and Paralympic sailing events will be held.
At low tide, mountains of household refuse, old sofas and even washing machines are seen.
An Associated Press analysis in November of more than a decade’s worth of Rio state government tests on waterways across the city showed fecal coliform pollution levels far above those considered safe by Brazilian or US law.
That pollution means nearly all beaches dotting the 383-square-kilometre bay have long been abandoned by swimmers, and some health experts warn of risks to athletes who come into contact with the water.
Elite sailors have warned that high-speed collisions with floating detritus could damage or even sink sailboats during the Olympics.
Water pollution issues began making headlines in Brazil’s local press again in recent days, after thick patches of brown foam appeared along the city’s most popular beaches like Copacabana as the Southern Hemisphere summer hits full stride.
Rio’s beaches, overwhelmed with holiday visitors, have been inundated with rubbish, much of it floating in water just yards (metres) from the sand.
That’s where authorities hope the eco-boats will make an impact.
However, the vessels don’t address sewage, but authorities insist they’ll make a big dent in the overall pollution.
“Our objective is to not to have floating garbage in Guanabara Bay,” said Gelson Serva, who heads the state government’s latest bay clean-up program, an $US840 million ($A941 million) project that includes efforts to expand the capacity of the city’s strained sewage treatment system.
Only 30 per cent of Rio’s sewage is treated, with the rest flowing into area rivers, the bay, local lagoons and its world-famous beaches.
“Those who live around the bay can already notice a difference over the past two years,” Serva said.