The hits keep on coming in the race for the District 3 state Senate race, with Mark Leno today bashing Democratic primary rival Joe Nation on an issue he has made the heart of his campaign: the environment.

In a release, the Leno campaign accuses Nation of being close to corporations whose actions have been to the detriment of the state’s environment. The campaign attacks Nation for what it says is his support for selling bottled water flowing from Mount Tamalpais; for voting to weaken an alternative fuels bill; and for supporting a cap-and-trade bill that would accelerate pollution.

Nation, who served in the state Assemblyman from 2000 to 2006, has frequently mentioned during the campaign what he says is his commitment to environmental issues like global warming. He has also been quick to point out that in 2006 he was one of the authors of AB 32, California's Global Warming Solutions Act and that has also worked with the environmental consulting firm ENVIRON.

In the release, the Leno side accuses Nation of being disingenuous in his focus on the environment. "Mark is the true environmentalist in this race, not a johnny-come-lately to the cause," Larry Fahn, a former Sierra Club President and Leno supporter, says in the release.

The Nation campaign, for its part, hit back at Leno with a release of its own, accusing him of not doing enough to stop a Rohnert Park casino plan that, the Nation side said, would hurt the environment.

Nation’s campaign also targeted Leno, a state Assemblyman, on the issues of bottled water and cap-and-trade.

"If Mark was concerned about bottled water why didn't he say anything when his political mentor, Willie Brown, not just looked into it but actually did bottle water?" asked Nation adviser Jim Ross, referring to the former San Francisco Mayor who served while Leno was on the San Francisco Board of Supervisors. "Joe Nation is proud to stand with Al Gore and against George Bush in supporting Cap and Trade. Why is Mark Leno opposing Al Gore's proposal to deal with global climate change?"

Nation, Leno, and incumbent Carole Migden are competing in a June 3 primary for the District 3 seat, which spans the areas of San Francisco, Marin, and Sonoma.