Surface and Rainwater Chemistry in Sri Lanka A Risk of Acidification
Chemical constituents of surface and rain water in Sri Lanka were analysed to examine the susceptibility of aquatic environment for episodic acidification. The buffer intensity of different types of surface water ranged from 8.09 ± 4.61 × 10 4 to 55.05 ± 21.18 × 10 4 moles l 1 pH 1 . The pH values of the rainwater samples collected island-wide once and at Kandy on a regular basis varied from 4.82 to 7.30 and from 4.46 to 6.89 respectively. About 37% of rainwater samples collected island-wide and at Kandy had pH range of 5.40-5.80. Rainwater collected from urban centres with high population densities had moderate concentrations of nitrate, sulphate and chloride ions. Although a majority of rainwater samples were within the pH defined for non-contaminated rainwater, there is a tendency towards slight acidification. If acid rain prevails, headwater streams and rivers draining the wet zone and reservoirs located at the highest elevation are more susceptible for episodic acidification.
Akimoto, H. and H. Narita (1994). Distribution of SO₂, NOₓ and CO₂ emissions from fuel combustion and industrial activities in Asia with 1º × 1º resolution. Atmos. Environ, 28: 213-225.
Amdit, R.L. and G.R. Carmichael (1995). Long range transport and deposition of sulfur in Asia. Water Air Soil Pollut., 85: 2283-2288.
APHA, 1988. Standard Methods for Examination of Water and Waste Water. 17th Edition. American Public Health Association, Washington DC.
Collier, K.J. and M.J. Winterbourn (1989). Impacts of wet land afforestation on the distribution of benthic invertebrates in acid streams of west land, New Zealand. New Zealand J. Mar. Freshwat. Res., 23: 479-490.
Cooray, P.G. (1984). An introduction to the Geology of Sri Lanka (Ceylon). National Museum of Sri Lanka Publication. 340 p.
Cowling, E.B. (1982). Acid precipitation in historical perspective. Environ. Sci. Technol, 16: 110A-123A.
Cresser, M. and A. Edwards (1987). Acidification of freshwaters. Cambridge Environmental Chemistry Series, Cambridge University Press. 135 p.
Cresser, M.S., Edwards, A.C., Ingram, S., Skiba, U. and T. Peirson-Smith (1986). Soil acid deposition interaction and their possible effects on geochemical weathering rates in British upland. J. Geol. Soc. London, 143: 649-658.
Dissanayake, C.B. and S.V.R. Weerasooriya (1986). The environmental chemistry of Mahaweli river, Sri Lanka. Int. J. Environ. Studies, 28: 207-223.
Dissanayake, C.B. and S.V.R. Weerasooriya (1985). Environmental Chemistry of rainwater and tap water in Sri Lanka. Int. J. Environ. Studies, 6: 72-86.
Fowler, D., Cape, J.N., Leith, I.D., Patterson, I.S., Kinnaierd, G.M. and I.A. Nicholson (1982). Rainfall acidity in Northern Britain. Nature, 297: 383-385.
Galloway, J.N., Dianwu, Z., Jiling, X. and G.E. Likens (1987). Acid rain: China, United States and a remote area. Science, 236: 1559-1562.
Gibbs, R.J. (1970). Mechanism controlling world water chemistry. Science, 170: 1088-1090.
Harvey, B. (1980). Acid rain from man and nature. Quest, 14: 1-7.
Illeperuma, O.A. (2001). Acid rain - an overview. In: The proceedings of Workshop on Acid Rain Monitoring and Air Quality Monitoring and Management, February 12-15, 2001, PGIS, University of Peradeniya, 1-5 p.
Jensen, K.W. and E. Snevik (1972). Low pH levels wipe out salmon and trout populations in southernmost Norway. Ambio, 1: 223-225.
Jickells, T., Knap, A., Church, T., Galloway, J. and J. Miller (1982). Acid rain on Bermuda. Nature, 297: 55-57.
Kuylenstierna, J.C.I., Rodhe, H., Cinderby, S. and K. Hicks (2001). Acidification in developing countries: Ecosystem sensitivity and the critical load approach on a global scale. Ambio, 1: 20-28.
Likens, G.E. and F.H. Bormann (1974). Acid rain: a serious regional environmental problem. Science, 184: 1176-1179.
Ownbey, C.R. and D.A. Kee (1967). Chlorides in Lake Erie. Proceedings of the conference on Great Lakes Research. International Association for Great Lakes Res. 10: 382-389.
Phadnis, M.J., Carmichael, G.R., Ichikawa, Y. and H. Hayami (1998). Evaluation of long-range transport models for acidic deposition in East Asia. J. Appl. Meteor., 37: 1127-1142.
Rodhe, H., Galloway, J. and D. Zhao (1992). Acidification in southeast Asia—prospects for the coming decades. Ambio, 21: 148-150.
Schindler, D.W. (1988). Effects of acid rain on freshwater ecosystems. Science, 239: 149-157.
Silva, E.I.L. (1998). Water chemistry of the Nilambe Oya, a tributary of the Mahaweli River in the Central Mahaweli Valley. Some Physico-chemical characteristics. Sri Lanka J. Aqua. Sci., 3: 119-127.
Silva, E.I.L. (1999). Status of Surface Water Quality in Sri Lanka. SCOPE, 82: 111-124.
Streets, D.G., Carmichael, G.R., Amann, M. and R.L. Arndt (1999). Energy consumption and acid deposition in Northeast Asia. Ambio, 2: 135-143.
van Breemen, N., Burrough, P.A., Velthroust, E.G., van Dobben, H.F., de Witt, T., Ridder, T.V. and H.F.R. Reinjnders (1982). Soil acidification from atmospheric ammonium sulfate in forest canopy through fall. Nature, 299: 548-550.
Weninger, G. (1972). Hydrochemical studies on mountain rivers in Ceylon. Bull. Fish. Res. Stn. Sri Lanka (Ceylon). 23: 77-100.