A new scientific study has found a link between mercury released from coal-fired power plants and the increasing number of cases of autism. The study tracked how autism rates rose in certain counties in Texas where mercury emissions were rising. About 48 tons of mercury are released into the air annually in the United States from hundreds of coal-burning plants. Last month the U.S. blocked attempts to launch formal talks on a global treaty to ban mercury which has also been linked to other serious ailments in pregnant women and children.