Every time it rains, it is not pennies from heaven, but corrosive acid showering on the earth.

Much of it, it is said, is damaging sulfuric acid, a result of coal burning, that is pumped into the atmosphere from electric power plants and sent drifting to all corners of the globe.

The menace of "acid rain," as it is called in the environmental-science field, is certain to be heard about increasingly if coal moves into the preeminent energy position sought for it by the Carter administration.

Acid rain is attacking fish life, making lakes sterile, marring forest production, impregnating soil and snowcaps and working its way into the earth's ecosystem.

The first serious studies of acid rain are producing some grim and pernicious prospects fo the future, Leon S. Dochinger told a conference of environmental officials here yesterday.

"It is perhaps the most serious environmental dilemma of the century," Dochinger said, "we are talking about sulfur and nitrogen oxides, which come from coal burning and automobiles, from natural sources such as volcanoes and forest fires."

Dochinger is a Department of Agriculture air pollution specialist from Delaware, Ohio. He is co-author of a new paper on acid rain, from which he read yesterday at an Environmental Protection Agency research conference.

Among the findings that he, Gene E. Likens of of Cornell University and Norman R. Glass of an EPA branch in Corvallis, Ore., have come up with are:

Rain water, particularly in the eastern United States, has become increasingly acidic in the last 15 years. Data from New York and New England show that the acid content is one-third nitric acid, two-thirds, sulfuric acid.

Fresh water bodies in the Northeast, in eastern Canada and northern Europe - Norway and Sweden, where the problem is acute - are endangered by acid rainfall.

Fish populations principally trout and salmon, are declining in acidified lakes in Norway and Sweden. The same thing is happening in New York's Adirondack Mountain lakes - acidity is up and many of the lakes have no fish life.

There is a strong belief, although not entirely documented, that acid rain is impairing forest growth. The rate of growth has declined in the Northeast and in Scandinavia since 1950, and the thought is that the rain is a factor.

"The entire eastern United States is being inundated by acid precipitation, and it has grown during the last 17 years," Dochinger said. "But we still have a long way to go to know about the chemistry of this acidity in the United States."

Part of his message at EPA's interagency research message was that scientists must begin more serious weighing of the potential damage caused by acid-laden rains.

The problems, he said in an interview, is simple: "What goes up must come down."

Which is to say that each time a pollutant is released into the atmosphere it eventually will find its way back to earth, although in many cases it will be thousands of miles away from its source.

Dochinger said that most of the pollutants from the burning of fossil fuels "are being transported long distances" so that no place is immune from the acid rain.

For example, pollutants from, say, coal burned in Montana might eventually come down in Ohio's rain. Maine's acid rain may have started at a power plant in Canada. Sweden's acid rain may come from West Germany.

"It is a global problem," Dochinger said, "and there is no way to trace it or to stop it because it does not recognize boundaries."

"The full consequences must still be determined, but we believe that we have shown through cirumstantial and field evidence that significant changes are occuring," he said.