Water, Air, and Soil Pollution

, Volume 85, Issue 2, pp 433–438

A preliminary assessment of nitrogen-based fresh water acidification in southeastern Canada

  • D. S. Jeffries
Part I Lake Acidification and its Effects


Sulphate deposition is the primary cause of acidification in northeastern North America, and new SO2 emission control is being implemented. However, continuation of existing levels of N deposition may undermine the environmental benefits derived from SO2 control. This likelihood has been assessed for Canadian lakes. Maximum N deposition (∼13 kg N ha−1 yr−1) occurs in south-central Ontario and southwestern Quebec. Regional median NO3levels are generally low (<5 μeq L−1) suggesting that on average, N-based acidification is minor compared to the S-based component. However, examination of the seasonal NO3pattern at 5 intensively monitored basins reveals that 2 of them (in Ontario and Quebec) have incipient N saturation. A regional status for nitrogen-based acidification was qualitatively assessed by classifying survey data to identify cases of NO3leaching. Many lakes throughout southeastern Canada exhibit some leaching, particularly those in south-central Ontario and southwestern Quebec. While the evidence for a deposition-acidification link appears strong, sources of N other than the atmosphere should be considered for certain anomalous cases.

Key words

nitrogen water acidification regional assessment chemical classification nitrogen saturation 


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Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • D. S. Jeffries
    • 1
  1. 1.National Water Research InstituteBurlingtonCanada

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