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95 Acidic Deposition: Sources and Effects

Part 8. Water Quality and Biogeochemistry

  1. Charles T Driscoll1,
  2. Kathy Fallon-Lambert2,
  3. Limin Chen1

Published Online: 15 APR 2006

DOI: 10.1002/0470848944.hsa095

Encyclopedia of Hydrological Sciences

Encyclopedia of Hydrological Sciences

How to Cite

Driscoll, C. T., Fallon-Lambert, K. and Chen, L. 2006. Acidic Deposition: Sources and Effects. Encyclopedia of Hydrological Sciences. 8:95.

Author Information

  1. 1

    Syracuse University, Civil and Environmental Engineering Department, Syracuse, NY, US

  2. 2

    Ecologic: Analysis and Communications, Quechee, VT, US

Publication History

  1. Published Online: 15 APR 2006


Acidic deposition delivers acids and acidifying compounds to the Earth's surface, which are then transported through soil, vegetation, and surface waters and, in turn, set off a cascade of adverse ecological effects. Acidic deposition has altered forest soil by accelerating the leaching of available base cations, enhancing the accumulation of sulfur and nitrogen, and increasing the concentration of dissolved inorganic aluminum in soil waters. Soils that are compromised by acidic deposition are less able to neutralize additional amounts of acidic deposition, and provide poorer growing conditions for plants. Acidic deposition has impaired the surface water quality by lowering pH, decreasing acid-neutralizing capacity (ANC), and increasing concentrations of dissolved inorganic aluminum. These changes have reduced the species diversity and abundance of aquatic life. Regulatory controls initiated in Europe and North America over the last three decades have decreased emissions of sulfur dioxide and to a lesser extent nitrogen oxides. Emission reductions have resulted in widespread decreases in concentrations of sulfate in surface waters, with some waters showing an increase in ANC. Given the loss of acid-neutralizing base cations and the accumulation of sulfur and nitrogen in soil, many ecosystems have become more sensitive to additional acidic deposition and recovery will likely be delayed. Long-term research shows that deeper emissions cuts will lead to greater and faster recovery from acidic deposition in impacted regions.


  • acid rain;
  • acidic deposition;
  • acidification;
  • emissions;
  • nitrate;
  • sulfate;
  • watershed