The 1992 United Nations Conference on Environment and Development in Rio de Janeiro caused a serious pollution problem. Brazilian scientists and environmentalists reported that the influx of 30,000 attendees left the area around the Riocentro conference site mired in sewage after overtaxing local treatment facilities. Fernando Almeida, a scientist at Rio's Federal University, calculated that the 12-day Earth Summit added nearly 13,000 gallons of barely treated sewage to nearby streams and rivers, killing thousands of fish and boosting pollution levels on beaches nearly six miles away.

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