Sen. Benjamin L. Cardin's proposal to strengthen cleanup of the Chesapeake Bay cleared the Senate Environment committee today with bipartisan support, but not before the Maryland Democrat made concessions to Republican opponents.

The revised measure, which still faces a very steep climb in this election year, no longer codifies a Bay-wide pollution limit, or "Total Maximum Daily Load" (TMDL) for nitrogen, phosphorus and sediment, that the U.S. Environmental Protection Agency is developing.

Environmentalists had considered that provision a key element of the Cardin plan, which is designed to strengthen the federal Clean Water Act by giving EPA the authority it needs to enforce a cleanup of the Bay's waters by 2025.

A lobbyist for the Chesapeake Bay Foundation, a leading backer of the measure, said the legislation is still very strong, despite dropping the TMDL language.

The changes give it a chance of gaining approval by the full Senate before the current session of Congress ends.

The House has still not acted on a companion measure, sponsored by Democratic Rep. Elijah Cummings of Baltimore, and the odds of the legislation making it to President Barack Obama's desk this year are not good. Also still to be considered: funding for the measure, which has a price tag in excess of $2 billion over five years, much of it to help state and local governments and farmers deal with pollution runoff.

Agriculture interests are strongly opposed. They contend Cardin's plan would impose a crushing new financial burden on farmers in the six-state area that makes up the Bay watershed. The committee voted down several amendments by Republican Sen. John Barrasso of Wyoming, including one that would have given state and federal agriculture officials a bigger say in regulating pollution from farms.