Concerns about toxics discharged from an unlined coal ash waste dump in suburban Washington, DC have prompted four environmental groups to give formal notice that they intend to sue Mirant MD Ash Management, LLC and Mirant Mid-Atlantic, LLC Corporation of Atlanta, Georgia for Clean Water Act violations in Maryland. The Brandywine Coal Combustion Waste Landfill receives fly ash and bottom ash from Mirant’s coal-fired Chalk Point Power Plant, the largest power plant in Maryland. Mirant says the 40-year-old plant is ISO 14001:2004 certified, which means it meets a widely accepted international standard for environmentally responsible operation