Big agribusiness shelled out millions of dollars lobbying Congress to block efforts to restore Clean Water Act protections, clean up the Chesapeake Bay and regulate pesticide discharges to waterways, according to an Environment America study released today.

"When Wall Street runs the farm, pollution runs off into our environment," said Piper Crowell, clean water advocate for the conservation advocacy group. "Giant agricultural companies are throwing around millions of dollars to continue polluting our rivers, lakes and oceans."

The study, titled "Growing Influence: The Political Power of Agribusiness and the Fouling of America's Waterways," details lobbying expenditures and campaign contributions of corporate agribusiness. It found that over the last decade, 10 large agribusiness interests gave $35 million to congressional candidates and more than $120 million to state-level candidates, party committees and ballot measures.

From 2005 to 2010, the top 10 agribusiness interests spent $127 million lobbying Congress and federal agencies. According to the study, Monsanto Co. and the American Farm Bureau Federation topped the list, fielding 80 lobbyists in Washington, D.C., last year.

Don Parrish, senior director of regulatory relations at the American Farm Bureau, said he had not seen the study but was not sure where Environment America got its information.

"The American Farm Bureau is a grass-roots lobbying group. The American Farm Bureau Federation also does not have a PAC [political action committee]. I'm not sure what they're referring to or how they got their information," Parrish said.

According to the study, lobbyist efforts worked to block a 2010 effort to restore Clean Water Act protections to all U.S. waterways. Agribusiness lobbyists also opposed federal legislation last year that would have required air polluters to help restore the Chesapeake Bay. Lobbyists also fought legislation that would have required U.S. EPA to tighten its regulation of pesticide discharges to waterways.

Nutrient discharges from agricultural areas have been documented as contributing to water contamination in the country, specifically in the Chesapeake Bay and Gulf of Mexico regions. Nutrients can cause large algae blooms, which suck oxygen from the water when they decompose, creating what are known as "dead zones."

Parrish said farmers have made strides in improving water quality.

"Our strength comes from our grass-roots membership, and our farmers care deeply about the environment," Parrish said. "If you look at USDA's data, which is statistically reliable, it indicates that farms have made significant gains in improving water quality. I'm proud of our members' track record, and we're doing things every day to improve water quality on the farm."

The study comes a week after the House voted on a funding bill with amendments that would limit the government's ability to enforce clean water laws.