Wet and dry deposition in the AOSR collected by ion exchange resin samplers

Abstract

Atmospheric deposition of nitrogen (N), sulfur (S), and base cations was measured across the network of jack pine sites in the Athabasca Oil Sands Region using ion exchange resin (IER) collectors. Deposition was measured in forest clearings (bulk deposition) and under jack pine canopies (throughfall). As noted previously for other pollutants, throughfall deposition of NO₃-N and NH₄-N decreased exponentially within a 20-25 km zone surrounding the industrial center. At a distance of 20 km from the industrial center N deposition decreased by 88%, while S and base cations decreased by 56 and 72% respectively, showing a greater footprint. Deposition of NH₄-N in the AOSR was on average double that of NO₃-N. Results of this study support the hypothesis that eutrophication effects to sensitive organisms such as epiphytic lichens may be of greater concern than acidification because acidic deposition is matched by equivalent amounts of buffering base cation deposition. However, the zone at risk of excess N effects may be limited in size as indicated by the steep decrease in N deposition with distance from the source areas.

Citation

Fenn, Mark. 2015. Wet and dry deposition in the AOSR collected by ion exchange resin samplers. In: Clair, T.A.; Percy, K.E., eds. Assessing forest health in the Athabasca Oil Sands Region. WBEA Technical Report: 40-50. Chapter 3.