Ocean-going ships will have to treat ballast water before it is released into the Great Lakes. The U-S Senate approved a measure requiring the E-P-A to draw up rules on the new policy. Conservationists and the shipping industry have been arguing for years over the regulation of the pollutant. Supporters of the new rule say ballast water contains viruses, algae, and many invasive organisms which have endangered the lakes’ ecosystem. The bill goes before the U-S House of Representatives next.