Ever drink from a bottle of water and notice a plasticky taste? Or reheat a meal with plastic wrap over it in the microwave? Or eat vegetables from cans, which often have plastic liners in them?

I've known for a while that it's not good to drink from a bottle of water that gets heated up in the car because "chemicals" from the plastic might leach into the water. But it wasn't until the other day when I spoke with Larisa Ruoff, director of shareholder advocacy for Green Century Capital Management (advisor for the Green Century mutual funds), that I learned the name of one of the chemicals-bisphenol A or BPA-and it's in water bottles, baby bottles, plastic wrap, can liners and other food and beverage containers. Although there's debate about the evidence of BPA's harmfulness, some studies show that 90% of us have detectable levels of it in our bloodstream, and BPA has been shown to disrupt reproductive development and function in laboratory animals, according to WebMD. A new study shows it lingers in the body longer than previously believed, and it's suspected that BPA causes behavioral changes and other problems in children. Ten days ago, a group of baby bottle manufacturers agreed to voluntarily stop using BPA in their bottles after attorneys general in Connecticut, Delaware and New Jersey asked them to.

Green Century began raising concerns about BPA some time ago. In 2006, the company worked with Whole Foods, which agreed to remove baby bottles containing BPA from its shelves, Ruoff notes. As a result of its continuing discussions with Whole Foods, the company is taking steps to eliminate BPA from other store products as well. Green Century sent letters to 15 packaged food companies, including ConAgra, Campbell Soup Company and the Coca-Cola Company, requesting information on their policies and procedures regarding BPA. Green Century plans to rank the companies on their use of the chemical and their efforts to identify and implement alternatives..

Shareholder advocacy efforts like this one are an important part of what Green Century and many other firms involved with socially responsible investing do. "We believe that being an active investor and using our ownership role in companies can provide a unique service and encourage companies to improve their practices," Ruoff says.

Encouraging dialogues and raising questions about potential problems can help a company identify risks that affect long-term shareholder value, she adds.

Another one of Green Century's ongoing shareholder advocacy efforts has been trying to convince Chevron Corp. to report on environmental damage from its expansion of oil exploration in the Canadian tar sands. According to Canada's Environmental Defence, the tar sands are "the most destructive project on Earth." Green Century believes that Chevron and other companies that are expanding operations in the tar sands face risks associated with the environmental damage of their projects. In February Ceres, an alliance of investor groups, singled out nine companies, including Chevron, for not accounting for changes brought on by global warming. Chevron was named to Ceres' Climate Watch List for its extensive investments in Alberta, Canada's oil sands, and for resisting shareholder requests to disclose potential financial risks associated with the carbon-intensive extraction, which encompasses millions of acres.

Last year, 25% of shareholders voted in favor of a resolution asking Chevron to issue such a report. Green Century has refiled a resolution this year, too. "As investors, we're concerned that the company is not disclosing substantial risks associated with the  environmental impacts of expanding its tar sands operations," Ruoff says.

Meanwhile, President Obama has taken the stance that oil extracted from the tar sands can be made a clean energy source, according to Bloomberg.com.

Green Century also is involved in a lot of other shareholder advocacy efforts, including working with the Center for Political Accountability and others to push companies to provide more disclosure in political spending.

Particularly after what's happened over the last few years to create the global financial crisis, a lot more accountability on many fronts is needed.