Something Fishy About Acid Rain . . .

By Denise Grady

Across Canada and the northern U.S., it has long been known, entire tracts of wilderness are dotted with lakes and streams that are essentially devoid of aquatic life. Most scientists believe the havoc is caused by airborne pollutants that are chemically transformed in the atmosphere and fall to earth in unusually acidic precipitation. Called acid rain, the phenomenon now stands accused of laying waste marine life along the Atlantic Coast as well. In a report issued last week, the Manhattan-based Environmental Defense Fund charges that nitrogen oxides spewed from U.S. power plants, factories and automobiles have played a major role in destroying fish and other creatures in Atlantic bays and estuaries. Acid rain, concludes Michael Oppenheimer, an atmospheric physicist and one of the authors of the report, is "destroying the spawning grounds for East Coast fisheries."

The deadly marine impact of nitrogen, mainly from fertilizer runoff, sewage and animal wastes, has been recognized for years. But the E.D.F. study is the first to pinpoint acid rain as an important source of coastal pollution. Any overload of nitrogen feeds marine algae, which bloom into vast growths that block sunlight and deplete the oxygen supply, smothering fish and crustaceans. The E.D.F. reports that 25% of the nitrogen contaminating Chesapeake Bay is the result of acid rain; investigators found similar nitrogen levels in a preliminary study of the coastal waters of New York and North Carolina. The proposed solution: tighter state and federal restrictions on nitrogen oxide emissions.

Although no one disputes that Chesapeake Bay and other coastal ecosystems are becoming dangerously polluted by excess nitrogen, not all experts agree that acid rain plays a key role. David Cohen, a spokesman for the U.S. Environmental Protection Agency, believes the contribution of nitrogen oxides "is much lower than 25%." EPA scientists suspect that agricultural runoff and the dumping of industrial sewage are far worse culprits.

Others are also skeptical. Michael Pace, a scientist at the Institute of Ecosystem Studies in New York, who reviewed the report before it was released, found it "hard to believe" that airborne sources were so important. "The numbers are very soft," said Pace. "They are only rough estimates."

Whatever its failings, the report was well timed. Foot dragging by the Reagan Administration on acid rain was attacked on several fronts last week in Washington. Testifying before a House subcommittee, James Mahoney, the new director of the National Acid Precipitation Assessment Program, a group formed by Congress in 1980 to examine policy options on acid rain, distanced himself from a report by his predecessors that downplayed the problem.

The E.D.F. report coincided with a visit to Washington by Canadian Prime Minister Brian Mulroney, who has tried unsuccessfully for years to persuade the Reagan Administration to tackle the acid-rain problem. Mulroney last week called the situation a "rapidly escalating ecological tragedy." Even before his arrival, however, Washington rejected a Canadian proposal that the U.S. limit nitrogen-oxide emissions.

With reporting by Nancy Traver/Washington