Rio de Janeiro: Brown water, foul odours and floating trash are still marring the rivers, beaches and lagoons around Rio de Janeiro barely 75 days ahead of the Brazilian city hosting the Summer Olympics, with hopes fading that the pollution will be cleaned up before August. The washing machines, detergent bottles and tyres reported by the press to be floating in Rio's bays are just the tip of the iceberg when it comes to the waste in the city's waterways, reports Efe. The city's waterways also harbour underwater pockets of methane and hydrogen sulfide gas produced by the decomposition of organic matter, giving the waters a rotten egg odour, as well as fecal bacteria, viruses and microbes that can give those exposed to the water for prolonged periods headaches, nausea, conjunctivitis and even hepatitis. Guanabara Bay and Rodrigo Freitas Lagoon are the worst-affected bodies of water in the city, with experts saying that they have sustained nearly irreparable damage. Cleaning up the bay and the lagoon will take decades and cost millions of dollars, experts said. Officials, however, contend that the polluted bodies of water around the city do not pose a danger for Olympic competitors, arguing that the problem is one of appearance. Biologist Mario Moscatelli said the focus should shift from the better-known bodies of water, which are "a lost cause", and to areas closer to the southern part of Rio and the Olympic facilities, where the waters pose a danger to bathers but can be cleaned up in "four or five years". Jacarepagua Lagoon, located next to the Olympic facilities, "is in terminal condition", Moscatelli told Efe, adding that the body of water has been a dumping site for wastewater for years. A few weeks ago, "the bottom got stirred up and a large quantity of gas was released", covering the area around the polluted lagoon and making residents ill, Moscatelli said. Several competitors in the World Surfing Championships became ill earlier this month after coming into contact with Rio's polluted waters. The 2016 Summer Olympic Games will be held in Rio de Janeiro from August 5 to 21.