SWAMPSCOTT – Customers at the Whole Foods supermarket in Vinnin Square got their first exposure Tuesday to the company’s new policy on plastic bags.Instead of being asked whether they prefer paper or plastic, customers at the Paradise Road store were informed that recyclable paper is far more environmentally friendly than plastic, and the first 200 through the door were offered a heavy-duty plastic sack that can be reused.The company plans to completely eliminate plastic bags by April, in time for Earth Day.Faced with a growing push in some states and cities to ban or limit use of plastic bags, many grocers are encouraging consumers to recycle bags or bring their own. Whole Foods Market plans to do away with the bags altogether.But many grocers report that about 90 percent of their shoppers still ask for plastic. And the bag makers, a billion-dollar industry, oppose bans, calling instead for consumers to reuse or recycle the bags. They favor recent legislation that encourages the recycling of bags but doesn’t ban them outright.Some states and municipalities have tried to curb the use of plastic bags or keep them from becoming litter. The New York City Council passed a law this month requiring stores to collect and recycle bags, following a similar law in the state of California.Last year, San Francisco passed the nation’s first bag ban, which took effect in November. The only plastic bags now allowed for big grocers are made of compostable material. Similar regulations are being considered by cities nationally, though proposals in places like Baltimore and Annapolis, Md., foundered last year.Plastic bags have a split personality: They draw shoppers with their durability and light weight, but environmentalists consider them a scourge, tangled in tree branches or swirling in waterways where they can be scarfed up by unsuspecting aquatic creatures.”Taking that old familiar checkout question ‘paper or plastic?’ to ‘what type of reusable bag do you have today?’ would be great,” said Kate Lowery, a spokeswoman for Whole Foods, which said Tuesday it will eliminate all plastic bags from its 270 stores in the United States, Canada and Britain by April.The United States lags behind many other countries globally in placing limits on plastic bags. Ireland and Germany levy fees for every bag handed out by stores, and several African nations have set thickness requirements that have effectively banned the flimsy thin bags that float in the air. Earlier this month, China, the world’s fastest growing economy, banned free plastic shopping bags and encouraged people to use cloth ones instead.”This issue is not going away. It is not necessarily going to take over the plastic bag market in a year or two, but it is indicative of a real trend,” said Allen Hershkowitz, director of the solid waste program at the Natural Resources Defense Council, an environmental group.