And average levels in bodies of surface water globally are 10 times higher than they were 50 years ago, ranging from 10 parts per billion in Europe to hundreds of parts per billion in South America. In the U.S., the Environmental Protection Agency has declared that no level at all in water supplies is safe. The European Union has reduced its standard for allowable lead in drinking water from 10 parts per billion to 5 parts per billion. Lead is highly toxic, even at tiny concentrations, especially affecting children as they grow. They are either impossible or very expensive to completely remove by conventional methods such as chemical precipitation or membrane filtration. And unlike organic pollutants, most of which can be eventually broken down, heavy metals don't biodegrade, but persist indefinitely and bioaccumulate.
alone, more than 12,000 miles of waterways are impacted by acidic mine-drainage-water rich in heavy metals, the country's leading source of water pollution. Lead and other heavy metals in water are a significant global problem that continues to grow because of electronic waste and discharges from mining operations. The findings are detailed today in the journal Nature Communications Earth and Environment, in a paper by MIT Research Scientist Patritsia Statathou Brown University postdoc and MIT Visiting Scholar Christos Athanasiou MIT Professor Neil Gershenfeld, the director of CBA and nine others at MIT, Brown, Wellesley College, Nanyang Technological University, and National Technical University of Athens. Such a fully sustainable system would not only purify the water but also divert what would otherwise be a waste stream needing disposal. The method is so efficient that the team has calculated that waste yeast discarded from a single brewery in Boston would enough to treat the city's entire water supply.
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