Effect of sulphur dioxide on precipitation and on the sulphur content and acidity of soils in Alberta, Canada

Abstract

Rain and snow in Alberta are seldom acid. The S content of snow is so low that the snow pack gives a deposition of less than 1 kg S/ha, even downwind from large SO₂ emission sources. Rainfall contributes at the most 4 kg S/ha yearly near SO₂ sources, and only about 1 kg S/ha in clean areas. However, rain intercepted by forest trees exposed to SO₂ emission becomes acid (pH 3.5 to 4.5) and has a S content of 3 to 4 times greater than rain. Soils absorb large amounts of S from emissions (up to 50 kg S/ha annually) but much of the S is found in non-sulphate form. Soils are slowly acidified by the SO₂ at a rate estimated at 1 pH unit in 10 to 20 years. Water surfaces will absorb SO₂ emissions at a rate of about 4 to 15 kg S/ha annually. Particulates deposit 3 to 4 times as much S as is deposited by rainfall.

Parent Publication

• Proceedings of the first international symposium on acid precipitation and the forest ecosystem

Citation

Nyborg, M.; Crepin, J.; Hocking, D.; Baker, J. 1976. Effect of sulphur dioxide on precipitation and on the sulphur content and acidity of soils in Alberta, Canada. In: Dochinger, L. S.; Seliga, T. A., eds. Proceedings of the first international symposium on acid precipitation and the forest ecosystem; Gen. Tech. Rep. NE-23. Upper Darby, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 767-777