In a new study, Harvard University researchers find over 90 percent of potential new Canadian hydroelectric projects are likely to increase concentrations of the neurotoxin methylmercury in food webs near indigenous communities. The research forecasts potential human health impacts of hydroelectric projects and identifies areas where mitigation efforts, such as removing the top layer of soil before flooding, would be most helpful. The works uses factors such as soil carbon and reservoir design to forecast methylmercury increases for 22 hydroelectric reservoirs under consideration or construction in Canada.