Legislation is in the works that would give the federal Environmental Protection Agency greater authority to clean up pollution in the Chesapeake Bay. Maryland Senator Benjamin L. Cardin says the EPA would receive new power to impose sanctions on states failing to meet their cleanup targets. The sanctions could include a ban on new development. A region-wide pollutant-trading system to reduce agricultural runoff also could be a feature of the measure. In May, President Barack Obama signed an executive order to make the bay’s cleanup a priority.