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GUEST EDITORIAL Acid demsition in the wktern U.S. In March 1985 the World Resources Institute issued a report, “The American West’s Acid Rain Test,” which provides a comprehensive review of what is known and unknown about acid deposition in that region. The primary concerns of the study are ecosystem sensitivity, precipitation acidity, and source distribution and emission rates. As with so many environmental issues, SCNtiny and debate now proceed apace. And they.proceed with what appears to be a recurring risk-the potential polarization of various interest groups. The study identifies a number of mountainous regions in the West as ecologically sensitive, notably the Cascades, the Sierra Nevada, and the Rockies. These areas may, in fact, be more sensitive to acid deposition than areas in the eastern U.S. and Europe that are now experiencing chemical changes and biological damage due to air pollution. Acid deposition is observed in at least three of these sensitive areas, with annual average pH of 4.7-5.0 and wet sulfate deposition rates of 5-14 kgha-y. (In contrast, in the East, annual average pH ranges from 4.1 to 4.5, and wet sulfate deposition rates exceed 20 kgha-y.) Chemical changes attributable to acid deposition have been observed to include the decreasing alkalinity of some streams and two episodes of temporary lake acidification-one the result of an acidic pulse from snowmelt and the other owing to a large-volume, lowpH storm. Emissions of acid precursors in the West are only onequarter those in the East, but they are concentrated in a few major source areas, which are mostly situated upwind of sensitive regions. Emissions rates of S@ and NO, in the West are expected, on the average, to remain relatively constant during the next decade. In some areas, however, they may increase. Although biological damage that results from acid deposition has not been observed in the West, the existing situation clearly deserves attention. Concern stems from the apparently high level of vulnerability of mountain ecosystems; the wet sulfate deposition rates that, at their highest observed levels, approach those in areas where biological damage is now observed; the likelihood that rota1 acid deposition rates, for a given wet sulfate deposition rate, are higher in parts of the West than they are in the East or Europe (owing to the higher dry-tewet deposition ratios and the higher NO,t e S @ emissions ratios in some parts of the West); and the potential for increased emissions. Low lake alka0013E36w85F08190755M~.~ 0 1085ArnericanChemical society
lities and the threat to lakes from acidic pulses that result from snowmelt add to the concern. Unknown factors also breed concern. The onset of forest damage in Europe was unanticipaw, scientists are only beginning to develop an understanding of its causes. They cannot now predict whether forest damage due to air pollution will occur in the West; nor can they estimate the time scale for lake acidification in the face of continuing deposition. What may provide an immediate concern, however, is the potential for polarization among various interest p u p s because of their differing perceptions of the risk of ecological damage and the need for remedial action. Comprehensive, integrated research and monitoring efforts are needed in each of the three geographical areas identified to provide expeditiously the level of understanding required for making sound decisions in the future. California’s Kapiloff program is a notable example of this approach. Named for former assemblyman Lawrence Kapiloff, this program established and funded the state’s five-year acid rain research program. The legislation was passed late in 1981, and the program itself began in 1983. Such well-conceived strategies for protecting western ecosystems will emerge most effectively from cooperative efforts among regulatory, environmental, industrial, transportation, and public interests. We have the opportunity to develop these strategies under much more favorable circumstances than those found in re gions where damage occurs now. Let us pursue these ends, working together. But let us do it now.
FWip M. Roth, a cwurhor of ‘‘me American West’sAcid Rain Est.” is a California-bared independent consultant specializing in environmental issues. Envimn. Sei. Techd., MI. 19, No. 9,1985 766
