1Separating Natural Acidity from Anthropogenic Acidification in the

• Main Authors: Spring Flood, Northern Sweden, Hjalmar Laudon, Acta Universitatis Agriculturae Sueciae
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Northern Sweden
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.3039; http://info1.ma.slu.se/IMA/Publikationer/HjalmarL/silvestria160.pdf

Spring flood is an occasion for transient hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also very susceptible to anthropogenic acidification. Belief that acid deposition is primarily responsible for pH decline during spring flood has been an important factor in the decision to spend close to one billion Swedish crowns to lime surface waters in northern Sweden during the last decade. The objective of this work is to present an operational tool, the Boreal Dilution Model (BDM), for separating and quantifying the anthropogenic and natural contributions to episodic acidification during spring flood episodes in northern Sweden. The limited data requirements of 10-15 stream water samples before and during spring flood make the BDM suitable for widespread use in environmental monitoring programs. This creates a possibility for distin-guishing trends and spatial patterns in the human impact as well as natural pH decline. The results from applying the BDM, and a one point “pBDM ” version of the model, in northern Sweden demonstrate that the anthropogenic component associated with spring flood episodes is now generally limited. Instead it is the combination of natural organic acidity and dilution of the buffering capacity that is the major driving mechanism of