Boston — It's raining ''vinegar'' in New England. The problem of acid rain, for months a thorn in the side of US-Canadian relations, is beginning to cause greater concern south of the border.
New York and Pennsylvania environmentalists long have complained of the effect such pollution has had on the land and water in their states. Now there is growing awareness among politicians and conservationists in New England that the problem is just as severe in their region.
A recent study by the National Wildlife Federation indicates that 15 states east of the Mississippi are ''highly vulnerable'' to the effects of acid rain, with the six New England states among those most severely affected. The acidity in the rain from one storm in Massachusetts during the test period was judged to be 2.9 on the pH scale, close to the acidity of vinegar. The study follows a report by the Interagency Task Force on Acid Precipitation last January showed the average rainfall in the Northeast was 10 times more acidic than normal.
Acid rain results when pollutants such as nitrogen oxides and sulfur dioxide mix with moisture in the air, forming a weak acid, and fall in the form of contaminated precipitation.
As the acid rain problem has enlarged beyond the borders of Canada, so have the political pressures to deal with it in this country. Sen. George Mitchell (D) of Maine introduced legislation in early October that would limit acid rain-causing emissions in a 31-state region east of the Mississippi to levels that existed as of the first of this year. The bill also would require a 10 million ton reduction in sulfur dioxide emissions during this decade.
With eight GOP cosponsors, the bill enjoys bipartisan support. But its chances for passage - along with a companion bill introduced on the House side by Rep. Toby Moffitt (D) of Connecticut - appear slim. This is because the measure is being tacked on as an amendment to the Clean Air Act, which is expected to undergo major revisions when it comes up for debate later this session.
The fact that the problem exists is the only ''given'' in debate over the legislation. The fouling of lakes and forest land is widespread and well documented. In addition to the ''death'' of many lakes in the Adirondak Mountains of New York due to high acidity, it is feared that acid rain may be contaminating reservoirs in the New England states as well.
But the Reagan administration is opposed to the bill. It argues that too little is known about the ability of land and water to fend off the effects of acid rain over the long run and about the importance of factors such as auto exhaust to the makeup of acid rain.
In addition, the cost of Senator Mitchell's proposed plan has been estimated at up to $2.8 billion, an unpalatably high figure for the Reagan administration. Kathleen Bennet, an assistant administrator for the Environmental Protection Agency (EPA) has called the bill the ''least cost-effective approach'' for dealing with the problem.
The EPA's position is that more research is necessary before a rational plan can be devised to combat the problem.
Peter Fairchild, executive director of NESCOM, an air pollution watchdog agency in the Northeast, says the EPA plan is ''not acceptable.'' He acknowledges that continued study of the problem is vital, but he believes the damage that already has occurred warrants immediate action.
Those favoring immediate action to combat acid rain also say they believe the cost of controls could be cut by instituting procedures such as: washing the coal before burning it to remove the bulk of the harmful pollutants; installing scrubbers that would allow plants to use less expensive high-sulfer coal; and using ''least emissions dispatching,'' a technique that emphasizes the greater use of those sources at a plant that are least polluting.