15 - was a large-scale regional phenomenon in much of Europe, that both precipitation and surface waters were becoming more acidic, and that long-distance (100-2000 km) transport of both sulfur- and nitrogen-containing air pollutants was occurring among the various nations of Europe. Oden also enunciated a series of hypotheses about the probable ecological consequences of acid precipitation decline of fish populations, decreased forest growth, increased plant diseases, and accelerated damage to materials. These conclusions and hypotheses led to a veritable storm of scientific and public concern about acid precipitation. The Swedish government responded to growing public and scientific interest by initiating an inquiry which cultimated in Sweden's Case Study for the United Nations Conference on the Human Environment "Air Pollution Across National Boundaries: The Impact of Sulfur in Air and Precipitation" (Bolin et al, 1972). - The major ideas in both the Ecology Committee Bulletin and the Swedish Case Study were much debated all over Europe. Two major scientific initiatives followed in short order. The first occurred in 1972 when the Norwegian government established the so called SNSF Project project called "Acid Precipitation: - a special interagency research Effects on Forests and Fish" with an annual budget of about 10,000,000 Norwegian Kroner (US $2,000,000). This huge project had two comprehensive goals: 1) To establish as precisely as possible, the effects of acid precipitation on forests and freshwater fish; and 2) To investigate the effects of air pollutants on soils, vegetation, and water to the extent required to support the primary objective. The second major initiative was the so called OECD Study which provided quantitative data on the long distance transport and deposition of atmospheric sulfur in both eastern and western Europe. The results, which were published 16 in 1977 by the Organization for Economic Cooperation and Development (OECD, 1977) confirmed many of the ideas presented in the Ecology Committee Bulletin and the Swedish Case Study regarding the long-distance international exchange of sulfur dioxide and acid precipitation among the nations of Europe. Scientific and Public Awareness in North America Concern about acid precipitation and its ecological effects in North America developed first in Canada and then later in the United States. Initial interests were focused on the effects of sulfur dioxide fumigation and associated acid precipitation near metal smelting operations, especially those near Sudbury, Ontario --the largest point source of sulfur in the world. During the early 1970's, interest spread to other parts of Canada as declining fish populations were discovered in more and more lakes remote from local sources of atmospheric sulfur in southern Ontario, and Nova Scotia. The first national monitoring program for precipitation chemistry in Canada was initiated by the Canadian Department of the Environment in 1975. The first detailed studies of precipitation chemistry in the United States were made by Junge and various collaborators during the 1950's (Junge and Wertz, 1958). The first regional monitoring of precipitation chemistry was done by a group of State Agricultural Experiment Station scientists from 1953-55 (Jordan et al, 1959). The first national monitoring program was established by the National Center for Atmospheric Research in 1960 (Lodge et al, 1968); but as has been the case in all such studies in the United States, these early programs were redirected and/or terminated so that no continuing records of long-term trends in precipitation chemistry are available. Scientific and public interest in acid precipitation and its ecological consequences were stimulated by Torsten Ahl and Svante oden at the 19th International Limnological Congress in Winnepeg, Manitoba in 1969 and by Oden in a series of 14 lectures at various institutions in the United States during the fall of 1971. 66-112 0-80--5 17 Further stimulus was provided by a series of publications by Gene Likens, John Cogbill, James Galloway, and Carl Schofield and others (Likens et al, 1972; Likens, 1976; Cogbill and Likens, 1977; Schofield, 1976; Galloway and Likens, 1976). Studies of various biological effects of acid precipitation were initiated at Cornell, North Carolina State, and other universities. David Shriner's (1974) dissertation demonstrated both direct injury to vegetation and various indirect effects through pathogens and parasites. Carl Schofield's (1975) research on extinction of fish populations in the Adirondack Mountains was especially alarming. Growing awareness of important impacts of acid precipitation on fish populations and potential effects on forest led the U. S. Forest Service to sponsor the First International Symposium on Acid Precipitation and the Forest Ecosystem in Ohio in May 1975. The Proceedings of this Symposium and the associated Workshop Report were published by Dochinger and Seliga (1976a, 1976b). At Congressional hearings in July 1975, Cowling (1976) testified on the inadequacy of research in the United States on acid precipitation. Specifically, the lack of a coordinated program of research on ecological effects and lack of a stable monitoring network were recognized as primary causes of our profound ignorance of acid precipitation. In the spring of 1976, however, a cadre of many scientists in various institutions and agencies throughout the United States began the process of creating the National Atmospheric Deposition Program (NADP) to meet these two critical needs (Kennedy, 1977; Galloway and Cowling, 1978). In the fall of 1977, the President's Council on Environmental Quality contracted with the NADP for the drafting of "A National Program for Assessing the Problem of Atmospheric Deposition (Acid Rain)". This publication (Galloway et al, 1978) provided the basis for a Presidential Initiative on Acid Precipitation which President Carter announced on August 2, 1979 in his Second Environmental Message (Cer, 1978). This initiative calls for a 10-year long, $10,000,000 18 per year program of research on the causes and consequences of acid precipitation. A standing Acid Rain Coordinating Committee was established by the President to plan and manage the program. The Committee consists of policy-level representatives from the Department of Agriculture, Department of Interior, Department of Energy, Department of Commerce, Department of State, the Environmental Protection Agency, the National Science Foundation, the Council on Environmental Quality, and the Office of Science and Technology Policy. Leadership for the Committee is provided by co-chairmen Rupert Cutler of the Department of Agriculture and Stephen Gage of the Environmental Protection Agency with the Council on Environmental Quality serving as Executive Secretary. The Present Status of Knowledge Concerning Acid Precipitation During the summer of 1979 a Cooperative Agreement was established between the U.S. Environmental Protection Agency, the National Atmospheric Deposition Program, and North Carolina State University for the management and coordination of research on the Effects of Acid Precipitation on Aquatic and Terrestrial Ecosystems. One of the major responsibilities specified in this Agreement is synthesis and integration of knowledge about acid precipitation and its ecological effects. Accordingly, an effort was made to summarize in a few statements of fact, the present status of knowledge in this area of science. A portion of this Status Report is presented in Table 2. These summary statements are providing a part of the background upon which scientists in various institutions and organizations in the United States and Canada will continue to build a scientific foundation for understanding the phenomenon of acid precipitation and its important ecological effects. The Present Status of Discussion About Public Policy In light of the statements of fact contained in Table 2, the following general judgments about public policy appear to be appropriate: Table 2. A Status Report on Acid Precipitation The summary statements listed below describe the general status of knowledge about acid precipitation and its ecological consequences as of December 1979. Acid precipitation (rain, snow, hail, dew, frost) is occurring in large regions of the eastern United States and Canada, Europe and Japan. It has also been reported in certain urban and rural areas in the western United States and may occur in other regions of the world. This widespread deposition of acidic precipitation and dry deposition results in large part from increased total emissions of oxides of sulfur and nitrogen. These substances are transformed in the atmosphere to sulfuric and nitric acids, transported over great distances, and deposited on vegetation, soils, surface water and materials. The ratio of sulfuric to nitric acids in precipitation varies from time to time and from place to place. In much of the eastern United States the average annual ratio of sulfuric to nitric acids is currently about 2:1; but nitric acid is becoming progressively more important relative to sulfuric acid. Tall stacks at power plants decrease ground level concentrations of S02 and Analyses of air-mass movements and chemical transformation in the atmosphere indicate that acid precipitation in one state or region of the United States or Canada results in part from emissions into the atmosphere in other states or regions often many hundreds of kilometers from the original source of the emissions. Contemporary precipitation is acidified by transformation products of both natural and man-made emissions of gases, aerosols and particulate matter. Major anthropogenic sources include combustion of fossil fuels (especially coal and oil), certain industrial processes (especially smelting of ores), exhausts from internal combustion engines, and nitrogen fertilization of agricultural and forest land. Acidity in precipitation is a reflection of the balance between the major cations and anions in precipitation. Thus, to understand the acidity of precipitation, it is essential to measure all the major anions and cations in precipitation (especially H+, NH4+, NO3, and S04, but also including K+, Na+, Ca, Mg, c1, co3, 503, and POZ). All of the major anions and cations transferred into ecosystems when it is raining or snowing (wet deposition) also are contained in the gases, aerosols, and particulate matter that are transferred from the atmosphere into ecosystems when it is not raining or snowing (dry deposition). Thus, in a chemical mass balance sense, it is both impossible and unrealistic to distinguish the biological effects of "acid precipitation" (wet deposition) from the biological effects of dry deposition. |