Analysis of trends in episodic acidification of streams in western Maryland
- University of Maryland Center for Environmental Science, Frostburg, MD (United States). Appalachian Laboratory
In this study we report on changes in the magnitude and mechanisms of episodic acidification of a small acid-sensitive stream in western Maryland (U.S.) during the 1990s, a period in which wet sulfate deposition declined by 10-25% due to implementation of the Clean Air Act Amendments (CAAA) of 1990. We observed a relatively minor trend in the magnitude of episodic acidification over this period, as measured by transient changes in acid neutralizing capacity ({Delta}ANC) and minimum values of ANC (ANC{sub min}) during 22 events sampled prior to and following CAAA implementation. Any relationship to changes in atmospheric deposition appears to be confounded by large hydroclimatological variability between the two sampling periods. Nonetheless, results obtained prior to implementation of the CAAA indicated that the mechanism of episodic acidification was mostly attributable to flushing of accumulated sulfate from the watershed, whereas results obtained post-CAAA indicated domination by base cation dilution. This shift in the mechanism of episodic acidification is qualitatively consistent with hydrochemical theory, as well as with empirical results from surface waters in other regions where dramatic declines in sulfate deposition have taken place. 31 refs., 5 figs., 1 tab.
- OSTI ID:
- 20947223
- Journal Information:
- Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 16 Vol. 41; ISSN ESTHAG; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Prediction of episodic acidification in Maryland Coastal Plain streams. Final report
Contemporary trends in the acid-base status of two acid-sensitive streams in Western Maryland
Related Subjects
29 ENERGY PLANNING, POLICY, AND ECONOMY
54 ENVIRONMENTAL SCIENCES
ACID NEUTRALIZING CAPACITY
ACIDIFICATION
AMENDMENTS
ANNUAL VARIATIONS
BIOLOGICAL RECOVERY
CLEAN AIR ACTS
DATA ANALYSIS
DEPOSITION
ENVIRONMENTAL IMPACTS
IMPLEMENTATION
MARYLAND
MONITORING
PH VALUE
SAMPLING
STREAMS
SULFATES
SURFACE WATERS
USA
WATER POLLUTION
WATERSHEDS