The clear waters of Ponkapoag Pond are deceptive, says Paul Godfrey, as he wades knee-deep to take a water sample. Eyeing the water with toes poised for relief from the July heat, a visitor stops just short of the water, when the scientist from University of Massachusetts at Amherst explains that the pond is ''polluted'' by acid rain.
Dr. Godfrey, director of the UMass Water Resources Research Center, is pleased by the onlooker's reaction, because, he says, unless acid rain is explained in blunt terms like that and literally ''brought into a person's backyard,'' the average person doesn't perceive it as a tangible problem.
Acid rain is largely still a mystery to scientists and lawmakers. The source, though not the effects, of acid rain is debated by industry, government, and scientists. The breakdown of biological chains has been directly related to the high acidity of rainwater. Problems believed caused by this include lower timber yields, loss of wildlife and foliage, and metal leaching out of water tables, forcing more costly drinking water treatment.
Rain that's acidic can't be seen or smelled like hazy air pollution or murky water pollution. It's most noticeable in headlines, political debates, and ''statistics from Washington,'' says Godfrey, who along with state officials and wildlife groups is promoting Massachusetts' Acid Rain Awareness Week.
''I get calls from people asking if it's safe to let their kids swim in the neighborhood pond. Well, (the effects of acid rain) will never reach the point where you can't swim,'' says Alan van Arsdale, program manager on acid rain assessment for the state's Environmental Quality Engineering Department.
An acidic pond like Ponkapoag may be safe for humans, but, like a swimming pool, it's not hospitable to wildlife. Ponkapoag wavers between the ''endangered'' and ''critical'' categories of acidity, measuring a 6 on the pH scale of acidity.
Another spring of heavy rainfall could sharply increase acidity levels, Godfrey says. On the pH scale, 7 is neutral; battery acid registers 1. At 6, mussels and crayfish will die; at 5.5, fish begin to disappear, and at 4.5 no fish exist. Massachusetts' rainfall averages 5.6.
The New England states and Canada have pointed the finger of blame at the smokestack industries of the Midwestern United States. But no conclusive link has been made. Nor has there been consistent scientific monitoring of acid rain's effects on any region.
Television meteorologists in Boston have been promoting Acid Rain Awareness Week on the air, and they agree that the issue is a hard one to convey to laymen.
''I don't think the public understands the pH scale. But they can understand, 'How does it affect the paint job on your car?,' '' observes Bruce Schwoegler of WBZ-TV.
But Godfrey has good reason to believe people can be taught to care about the effects of acid rain. ''Average citizens'' are the foundation of UMass's Acid Rain Monitoring (ARM) program, started by Godfrey. Believed to be the only project of its kind in the nation, the ARM program has attracted 900 volunteers and 75 private and state laboratories that each month sample and test the waters of more than 1,100 lakes and streams - a quarter of the state's water bodies - for acidity and alkalinity. Five months of ARM testing shows that some 38 percent of the water bodies are ''endangered'' or ''critical.''
The project ''brings home to volunteers that it's happening in their own yards or down the street. Most of them are (sampling water) in a pond in their backyard,'' Godfrey says.
''A lot of people have wanted to do something but couldn't because it seemed like a problem in Washington. The fact that they might have an impact has gotten a lot of people to sit up and be aware.''
Godfrey explains that the ARM project will set up a ''baseline'' of information. As the monthly acidity in Massachusetts waters is recorded by scientifically accepted procedures and evaluated by reputable laboratories, project results will begin providing information that, if collected 30 years ago , or even five years ago, would have pushed acid rain research further than it is today, he says.