| Volume 29, Number 2 | June 1998 |
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President Robert Henshaw Vice President Nicholas Clesceri Secretary Pamela Otis Treasurer Jeffrey Clock BOARD OF DIRECTORS G.S. Peter Bergen Charles W. Boylen Terrence Curran Nordica Holochuck Leonard Houston Charles Keene Thomas Lake Thomas Lynch Warren McKeon Susan Metzger Andrew Molloy William E. Pressman Barbara Rinaldi David Strayer Ivan P. Vamos Executive Director Stephen O. Wilson CURRENTS Editors Susan Metzger Pam Otis Richard Woods Graphic Design Jim Guderian Produced at LMS |
IS THE ACID RAIN PROBLEM
GETTING BETTER OR WORSE?
In one way or another each of us is making history by our actions every day. Gene E. Likens, President and Director of the Institute of Ecosystem Studies, has made several outstanding contributions by increasing our awareness of how human activities impact the environment. Dr. Likens and his colleague, Dr. E Herbert Bormann, began a comprehen- sive study of the Hubbard Brook Valley ecosystem in the White Mountains of New Hampshire 34 years ago. Hubbard Brook was the site of the first major quantitative study of ecology at the scale of an entire watershed. Likening the chemistry of streams to the circulatory system, Likens and Bormann systematically measured inputs and outputs to try to determine what constitutes a healthy ecosystem. By manipulating specific components of an entire watershed ecosystem (i.e,, clear cutting one area with various harvesting practices, while comparing with an uncut adjacent watershed), they were able to analyze and then predict the effects of various forestry activities on the northern hardwood forest. Perhaps Dr. Likens' most outstanding finding was the unusually low pH ofprecipita- tion, from which he coined the term "acid rain." In 1964 the pH of rain at Hubbard Brook was averaging about 4 on a7scstle of 1 to 14, in which 1 is highly acidic, 7 is-neutral, and 14 is highly alkaline. As pH is measured on a logarithmic scale, a pH of 4.2, for ex- ample, is 10 to 15 times more acidic than water not polluted with sulfur dioxide (SO,) and nitrogen oxides (NOx), two of the main industrial emissions that cause acid rain. SO, and NOx, released when fossil fuels are burned, form sulfuric and nitric acid in the rain that falls to the earth. Over time, the pH of rainfall at Hubbard Brook has been recorded as low as 2.85. In 1970 Dr. Likens noted that the pH of rain in the Finger Lakes region of New York as also about 4. By 1974 the problem made the front page of the New York Times and as regularly reported for several years. Industrial emissions from the Midwest were carried by predominantly westerly winds, unloading their acidic precipitation on the forests, rivers, farms, and cities of the Northeast. The pH of rain in the Hudson Valley is almost identical to that at Hubbard Brook. With national attention brought to the problem, the electric power industry issued a "contract" on Dr. Likens' acid rain research in the form of a several hundred thousand dollar call for proposals to prove him wrong. Much to their chagrin, no one was able to disprove his findings. Unable to deny the problem scientifrcally, industry public relations staff resorted to less honest tactics. Likens recalls a meeting with representatives from a Pittsburgh cold company (who sold their coal primarily to Midwest utilities) who frankly admitted that their major purpose was to "obfuscate, confuse, and delay" acid rain re- search. In the 1960s and 1970s most air pollution research focused on particulate matter, hich causes visible smog and soot. By the time the Clean Air Act came up for amend- lent in 1990, the focus was clearly on acid rain. Billions of dollars were allocated for pollution prevention, mostly in the form of requiring the use oflow-sulfur coal and installing scrubbers, filters, and other pollution control technologies designed to control SO, emissions. As a result of pollution control efforts, SO, and particulates have steadily decreased since the Clean Air Act of 1970. |