Mercury contamination from mining practices 150 years ago is a widespread problem affecting many Sierra foothill lakes and rivers, and it poses a health danger to humans who enjoy eating wild caught fish. Environmental groups, water and government agencies and tribal leaders are looking at mercury and ways to deal with it in the future. In the latest step toward clean-up, Nevada Irrigation District's board of directors agreed to submit an application with other groups for a $1 million grant to remove mercury from Combie Reservoir. Mercury extraction on Combie and the Bear River that feeds it could serve as …