||Estimating critical loads of sulfate to surface waters in the Northeastern United States : a comparative assessment of three procedures for estimating critical loads of sulfate for lakes /
Shaffer, Paul W. ;
Rosenbaum, B. ;
Holdren, G. R. ;
Strickland, T. C. ;
McDowell, M. K.
||ManTech Environmental Technology, Inc., Corvallis, OR. ;Oak Ridge National Lab., TN. ;Science Applications International Corp., Oak Ridge, TN.;Corvallis Environmental Research Lab., OR.;Department of Energy, Washington, DC.
|| U.S. Environmental Protection Agency, Office of Research and Development, Environmental Research Laboratory,
Water pollution effects ;
Surface waters ;
Mathematical models ;
Study estimates ;
Water chemistry ;
Biological indicators ;
Acid neutralizing capacity ;
Air pollution ;
Air water interactions ;
Northeast Region(United States) ;
Critical loads ;
Direct/Delayed Response Project
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
||44 pages ; 28 cm
The objective of the U.S. critical loads program has been to develop a framework for estimating critical loads and to evaluate the effects of multiple assumptions inherent in those estimates. A general framework for developing critical loads estimates was developed by the UNECE (1990). A flow chart describing this procedure. The status report presents examples of efforts to estimate critical loads of sulfate for surface waters in the United States and discusses the effects of different assumptions on the final estimates. Sulfate in surface water was selected as the pollutant-receptor pair for the current examination because the information necessary to evaluate the assumptions are better developed for this pair than for any other candidates (e.g., nitrate effect on soil acidification) in the U.S. It is important to note that no attempt to evaluate or identify any of the results presented here as right/wrong, or to rank the reliability of results was made. The objective, rather, has been to generate sets of critical load estimates using multiple models and data sets, and to compare the results. The results presented here represent a first step in the critical evaluation of models used to estimate critical loads and to cross-validate model-based estimates. The results have demonstrated substantial variability in critical loads estimated using different datasets and procedures. Given these results, it seems clear that extensive review, refinement, and verification of models and datasets will be required before any critical load estimates can be reliably used.
Includes bibliographical references. "November 1991." Microfiche.