Dilution and the elusive baseline

TitleDilution and the elusive baseline
Publication TypeJournal Article
Year of Publication2012
AuthorsLikens, GE, Buso, DC
JournalEnvironmental science & technology
Pagination4382 - 4387
Date Published2012/04/17/
ISBN Number1520-5851
KeywordsAcid Rain, Electric Conductivity, Environmental Monitoring, New Hampshire, Nitrates, Rivers, Sulfates, Trees, Water Pollutants, Chemical

Knowledge of baseline conditions is critical for evaluating quantitatively the effect of human activities on environmental conditions, such as the impact of acid deposition. Efforts to restore ecosystems to prior, "pristine" condition require restoration targets, often based on some presumed or unknown baseline condition. Here, we show that rapid and relentless dilution of surface water chemistry is occurring in the White Mountains of New Hampshire, following decades of acid deposition. Extrapolating measured linear trends using a unique data set of up to 47 years, suggest that both precipitation and streamwater chemistry (r(2) >0.84 since 1985) in the Hubbard Brook Experimental Forest (HBEF) will approximate demineralized water within one to three decades. Because such dilute chemistry is unrealistic for surface waters, theoretical baseline compositions have been calculated for precipitation and streamwater: electrical conductivity of 3 and 5 μS/cm, base cation concentrations of 7 and 39 μeq/liter, acid-neutralizing capacity values of

Short TitleEnviron. Sci. Technol.