Crews working to clean up the West Lake Landfill in St. Louis County detected contamination in nearby groundwater, forcing the U.S. Environmental Protection Agency to investigate whether radium might have left the site. In a periodic update to nearby communities last month, the EPA said it would add groundwater monitoring wells around the site, which sits in Bridgeton, about a mile from the banks of the Missouri River. The expansion, which came after contamination was detected at the edge of…