Abstract
Experimental data on the precipitation chemistry in the semi-arid savanna of South Africa is presented in this paper. A total of 901 rainwater samples were collected with automatic wet-only samplers at a rural site, Louis Trichardt, and at an industrial site, Amersfoort, from July 1986 to June 1999. The chemical composition of precipitation was analysed for seven inorganic and two organic ions, using ion chromatography. The most abundant ion was SO4 2 − and a large proportion of theprecipitation is acidic, with 98% of samples at Amersfoort and 94% at LouisTrichardt having a pH below 5.6 (average pH of 4.4 and 4.9, respectively). This acidity results from a mixture of mineral and organic acids, with mineral acids being the primary contributors to the precipitation acidity in Amersfoort, while at Louis Trichardt, organic and mineral acids contribute equal amounts of acidity. It was found that the composition of rainwater is controlled by five sources: marine, terrigenous, nitrogenous, biomass burning and anthropogenic sources. The relative contributions of these sources at the two sites were calculated. Anthropogenic sources dominate at Amersfoort and biomass burning at Louis Trichardt. Most ions exhibit a seasonal pattern at Louis Trichardt, with the highest concentrations occurring during the austral spring as a result of agricultural activities and biomass combustion, while at Amersfoort it is less pronounced due to the dominance of relatively constant industrial emissions. The results are compared to observations from other African regions.
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Ambus, P. and Christensen, S., 1994: Measurements of N2O emission from fertilized grassland: An analysis of spatial variability, J. Geophys. Res. 99, 16549-16555.
Andreae, M. O., Talbot, R. W., Andreae, T. W., and Hariss, R. C., 1988: Formic and acetic acid over the central Amazon region, Brazil, 1, dry season, J. Geophys. Res. 93, 1616-1624.
Andreae, M. O., Talbot, R.W., Berresheim, H., and Beecher, K. M., 1990: Precipitation chemistry in central Amazonia, J. Geophys. Res., 95, 16987-17000.
Ayers, G. P., Peng, L. C., Fook, L. S., Kong, C. W., Gillett, R. W., and Manins, P. C., 2000: Atmospheric concentrations and deposition of oxidised sulfur and N species at Petalinga, Malaysia, Tellus 52B, 60-73.
Brocard, D., Lacaux, C., Lacaux, J. P., Kouadio, G., and Yoboué, V., 1996: Emissions from the combustion of biofuels in western Africa, in J. S. Levine (ed.), Global Biomass Burning: Atmospheric, Climatic and Biospheric Implications, MIT Press, Cambridge, Massachusetts, pp. 350-360.
Cachier, H. and Ducret, J., 1991: Influence of biomass burning on African rains, Nature 352, 228-230.
Delmas, R., 1981: Contribution à l'étude des forêts équatoriales comme sources naturelles de dérivés soufrés atmosphériques, PhD Thesis, Université Paul Sabatier de Toulouse, Toulose, France.
Delmas, R., Loudjani, P., Podaire, A., and Menaut, J. C., 1991: Biomass burning in Africa: An assessment of annually burnt biomass, in J. S. Levine (ed.), Global Biomass Burning: Atmospheric, Climatic and Biospheric Implications, MIT Press, Cambridge, Massachusetts, pp. 126-133.
Dovland, H. and Pederson, U., 1996: Acid deposition in Europe, in D. M. Whelpdale and M. S. Kaiser (eds), Global Acid Deposition Assessment, World Meteorological Organization, pp. 53-67.
EPA, 1994: Quality Assurance Handbook for Air Pollution Measurement Systems, EPA/600R-94/038e, United States Environmental Protection Agency, Office of Research and Development, Washington.
Galloway, J. N., Likens, G. E., Keene, W. C., and Miller, J. M., 1982: Precipitation in remote areas of the world, J. Geophys. Res. 87, 8771-8786.
Galy-Lacaux, C. and Modi, A. I., 1998: Precipitation chemistry in the Sahelian Savanna, J. Atmos. Chem. 30, 319-343.
Galy-Lacaux, C., Carmichaël, G. R., Song, C. H., Lacaux, J. P., and Modi, I., 2001: Heterogenous processes involving nitrogenous compounds and Saharan dust inferred from measurements and model calculations Region, J. Geophys. Res. 106, 12559-12578.
Gillett, R.W., Ayers, G. P., Mhwe, T., Selleck, P.W., and Harjanto, H., 2000: Concentration of N and sulfur species in gas and rainwater from several sites in Indonesia, Water, Air and Soil Pollution 120, 205-215.
Graedel, T. E. and Eisner, T., 1988: Atmospheric formic acid from formicine ants: A preliminary assessment, Tellus 40, 335-339.
Held, G., Scheifinger, H., and Snyman, G. M., 1994: Recirculation of pollutants in the atmosphere, SA J. Sci. 90, 91-97.
Held, G., Scheifinger, H., Snyman, G. M., Tosen, G. R., and Zunckel, M., 1996: The climatology and meteorology of the highveld, in G. Held, B. J. Gore, A. D. Surridge, G. R. Tosen, C. R. Turner, and R. Walmsley (eds), Air Pollution and its Impacts on the South African Highveld, Environmental Scientific Association, Cleveland, pp. 60-71.
Herut, B., Starinsky, A., Katz, A., and Rosenfeld, D., 2000: Relationship between the acidity and chemical composition of rainwater and climatological conditions along a transition zone between large deserts and Mediterranean climate, Israel, Atmos. Environ. 34, 1281-1292.
Keene, W. C., Pszenny, A. A. P., Galloway, J. N., and Hartley, M. E., 1986: Sea-salt corrections and interpretation of constituents ratios in marine precipitation, J. Geophys. Res. 91, 6647-6658.
Lacaux, J. P., Delmas, R., Kouadio, G., Cros, B., and Andreae, M. O., 1992: Precipitation chemistry in the Moyombe forest of equatorial Africa, J. Geophys. Res. 97, 6195-6206.
Lara, L. B. L. S., Artaxo, P., Martinelli, R. L., Victoria, R. L., Camargo, P. B., Krusche, A., Ayers, G. P., Ferraz, E. S. B., and Ballester, M. V., 2001: Chemical composition of rainwater and anthropogenic influences in the Piracicaba River Basin, Southeast Brazil, Atmos. Environ. 35, 4937-4945.
Lee, B. K., Hong, S. H., and Lee, D. S., 2000: Chemical composition of precipitation and wet deposition of major ions on the Korean peninsula, Atmos. Environ. 34, 563-575.
Levine, J. S., Winstead, L. E., Parsons, D. A. B., Scholes, M. C., Scholes, R. J., Cofers III, W. R., Cahoon Jr., D. R., and Sebacher, D. I., 1996: Biogenic soil emissions of nitric oxide (NO) and nitrous oxide (N2O) from savannas in South Africa, J. Geophys. Res. 101, 23089-23697.
Likens, G. E., Keene, W. C., Miller, J. M., and Galloway, J. N., 1987: Chemistry of precipitation from a remote terrestrial site in Australia, J. Geophys. Res. 92, 13299-13314.
Madronich, S. and Calvert, J. G., 1990: Permutation reactions of organic peroxy radical in the troposphere, J. Geophys. Res. 95, 5697-5717.
Maenhaut, W., Salma, I., Annegarn, H. J., Andreae, M. O., and Cafmeyer, J., 1996: Regional atmospheric aerosol composition and sources in the eastern Transvaal, South Africa, impacts of biomass burning, J. Geophys. Res. 101, 23631-23650.
Mamane, Y. and Gottlieb, J., 1995: Ten years of precipitation chemistry in Haifa, Israel, Water, Air and Soil Pollution 82, 549-558.
Matson, P. A., Vitousek, P. M., and Schimel, D. S., 1989: Regional extrapolation of trace gas flux based on soils and ecosystems, in D. S. Schimel and M. O. Andreae (eds), Exchange of Trace Gases between Terrestrial Ecosystems and the Atmosphere, John Wiley and Sons, New York, pp. 97-108.
Norman, M., Das, S. N., Pillai, A. G., Granat, L., and Rodhe, H., 2001: Influence of air mass trajetories on the chemical composition of precipitation in India, Atmos. Environ. 35, 4223-4235.
Otter, L. B., Marufu, L., and Scholes, M. C., 2001: Biogenic, biomass and biofuel sources of trace gases in southern Africa, SA J. Sci. 97, 131-138.
Parsons, D. A. B., Scholes, M. C., Scholes, R. J., and Levine, J. S., 1996: Biogenic NO emissions from savanna soils as a function of fire regime, soil type, soil nitrogen and water status, J. Geophys. Res. 101, 23683-23688.
Piketh, S. J. and Prangley, A. R., 1998: Trajectory climatology of transboundary transport from the highveld, Eskom Report TRR/T98/038, Cleveland, 24 pp.
Piketh, S., Annegarn, H. J., and Tyson, P. D., 1999: Lower-tropospheric loading over South Africa: The relative contributions of aeolian dust, industrial emissions and biomass burning, J. Geophys. Res. 104, 1597-1607.
Puxbaum, H., Rendl, J., Allabashi, R., Otter, L. B., and Scholes, M. C., 2000: Mass balance of the atmospheric aerosol in a South Africa subtropical savanna (Nylsvley, May 1997), J. Geophys. Res. 105 (D16), 20697-20706.
Sanhueza, E. and Andreae, M. O., 1991: Emission of formic and acetic acids from tropical savanna soils, Geophys. Res. Lett. 18, 1707-1710.
Satsangi, G. S., Lakhani, A., Khare, P., Singh, S. P., Kumari, K. M., and Srivastava, S. S., 1998: Composition of rain water at a semi-arid rural site in India, Atmos. Environ. 32, 3783-3793.
SAWB, 1950: Upper Winds in Southern Africa, WB 13, South African Weather Bureau, Dept. of Transport, Pretoria, 281 pp.
SAWB, 1986: Climate of South Africa. Climate statistics up to 1984, WB 40, South African Weather Bureau, Department of Environment Affairs, Pretoria, 136 pp.
Saxena, A., Kulshrestha, U. C., Kumar, N., Kumari, K. M., and Srivastava, S. S., 1996: Characterization of precipitation in AGRA, Atmos. Environ. 30 (20), 3405-3412.
Schlesinger, W. H. and Hartley, A. E., 1992: A global budget for atmospheric NH3, Biogeochemistry 15, 191-211.
Siversten, B., Matal, C., and Pereira, L. M. R., 1995: Sulphur Emissions and Transfronteir Air Pollution in Southern Africa, Report 35, SADC ELMS, Lesotho, 112 pp.
Snyman, G. M. and Held, G., 1996: Vertical Distribution of Atmospheric Particulates and Meteorological Conditions during the 1996 Field Experiments, TRR/S96/206, Eskom, Johannesburg, 37 pp.
Talbot, R.W., Andreae, M. O., Berresheim, H., Jacobs, D. J., and Beecher, K. M., 1990: Sources and sinks of formic, acetic and pyruvic acids over central Amazonia, 2,Wet season, J. Geophys. Res. 95, 16799-16811.
Talbot, R.W., Beecher, K. M., Hariss, R. C., and Cofers III, W. R., 1988: Atmospheric geochemistry of formic and acetic acids at a mid-latitude temperate site, J. Geophys. Res. 93, 1638-1652.
Turner, C. R., Wells, R. B., and Olbrich, K. A., 1996: Deposition chemistry in South Africa, in G. Held, B. J. Gore, A. D. Surridge, G. R. Tosen, C. R. Turner, and R. D. Walmsley (eds), Air Pollution and its Impacts on the South African Highveld, Environmental Scientific Association, Cleveland, pp. 80-85.
Tyson, P. D., Garstang, M., Swap, R. J., Edwards, M., and Kållberg, P., 1996: An air transport climatology for subtropical southern Africa, International Journal of Climatology 16, 151-163.
Van der Walt, H., du Toit, P., Pienaar, J. J., and Julies, A., 1998: Integration of passive sampler monitoring in non-electrified residential areas into a modern ambient air quality monitoring network, Proceedings, 11th World Clean Air and Environment Congress, Durban, 13-18 September 1998, 5 pp.
Williams, M. R., Fischer, T. M., and Melack, J. M., 1997: Chemical composition and deposition of rain in Central Amazon, Brazil, Atmos. Environ. 31, 207-217.
WMO, 1997 (1998, 1999): Nineteenth (twentieth and twentyfirst) acid rain performance survey, World Precipitation Chemistry Center of the WMO QA/SAC, State University of New York, Albany.
Yoboué, V., 1991: Caractéristiques physiques et chimiques des aérosols et des pluies collectés dans la savanne humide de Côte d'Ivoire, PhD No. 914 Thesis, Université Paul Sabatier de Toulouse, Toulouse, France. 103 pp.
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Mphepya, J.N., Pienaar, J.J., Galy-Lacaux, C. et al. Precipitation Chemistry in Semi-Arid Areas of Southern Africa: A Case Study of a Rural and an Industrial Site. Journal of Atmospheric Chemistry 47, 1–24 (2004). https://doi.org/10.1023/B:JOCH.0000012240.09119.c4
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DOI: https://doi.org/10.1023/B:JOCH.0000012240.09119.c4