Trichloroacetic Acid as Additional Factor Contributing to Desertification in Southern Africa
- 58 Downloads
There has been an accelerated expansion of deserts in the past five decades. Recent data reveal that the atmogenically formed organic compound, trichloroacetic acid (TCA) is a contributory factor in addition to anthropogenic and natural sources. The aim of this study was to use TCA as an indicator for the possible occurrence of C2-chloroacetic acids; to assess the burden on the vegetation by using pine needles as a bio-indicator system and to deliberate on the possible role of TCA in the dynamics of the vegetation in southern Africa. Field experiments conducted on pine trees and on C3 and C4 crop plants under controlled laboratory conditions, have revealed that plants could be influenced positively or negatively by TCA. To obtain an integrated assessment of the pollution emission over a time span of at least one year, two-year-old pine needles of different Pinus species were used as a bio-indicator for TCA pollution at different measuring sites. The data of our investigation clearly indicate that areas exist in South Africa where the vegetation is burdened by ecotoxicologically relevant TCA contents comparable to those in central Europe and southern Russia where TCA was shown to play a role in the destabilisation of the steppe vegetation.
Unable to display preview. Download preview PDF.
- Bartenbach, S.: 2001, Hochtemperaturverhalten natürlicher Lignocellulosen am Beispiel südafrikanischer Gräser, Diplomarbeit, Friedrich-Schiller-Universität, Institut für Technische Chemie und Umweltchemie, Jena (Germany).Google Scholar
- Gabunshina, E.: 1997, How to Stop Desert, Environmental Protection Minister of the Republic of Kalmykia, Elista, Russia.Google Scholar
- Garcia, J.P., Beyne-Masclet, S., Mouvier, G. and Masclet, P.: 1992, ‘Emissions of volatile compounds by coal-fired power stations’, Atmos. Environ. 26A, 1582–1592.Google Scholar
- Lange, Ch. A., Kotte, K., Weissflog, L. and Pfennigsdorff, A.: 2003, ‘Fast Chlorophyll a Fluorescence Kinetics Analysis to Assess Phytotoxic Effects Induced by Trichloroacetic Acid (TCA) on Scots Pines (Pinus sylvestris L.) and Birches (Betula pendula Roth.)’, In: H. Landmesser (ed.), Chemie und Forstwissenschafliche Beitraege Tharandt/Contributions to Forest Sciences Tharandt, Beiheft 4, 86–104, Technical University Dresden, Dresden/Germany.Google Scholar
- Midgley, P.M. and McCulloch, A.: 1999, ‘Production, Sales and Emissions of Halocarbons from Industrial Sources’, in: O. Hutzinger (ed.), The Handbook of Environmental Chemistry, Vol. 4, Part E. Reactive Halogen Compounds in the Atmosphere, chapter 6, Springer, Berlin, pp. 155–190.Google Scholar
- Strauss, A.J., Krueger, G.H.J., Van Heerden, P.D.R., Pienaar, J.J. and Weissflog, L.: 2004, ‘Constraints on photosynthesis of C3 and C4 crop plants by trichloroacetic acid, an atmogenically generated pollutant’, S. Afr. J. Bot. (in print).Google Scholar
- Tyson, P.D.: 1997, ‘Atmospheric transport of aerosols and trace gases over southern Africa’, Prog. Phys. Geogr. 21, 79–101.Google Scholar
- Weissflog, L.: 2001, ‘Luftverschmutzung fördert Wüstenbildung’, HGFJahresheft 2001, Helmholtz-Gesellschaft für Forschung, Germany.Google Scholar
- Weissflog, L., Pfennigsdorff, A., Martinez-Pastur, G., Puliafito, E., Figueroa, D., Elansky, N., Nikonov, V., Putz, E., Krüger, G. and Kellner, K.: 2001, ‘Trichloroacetic acid in the vegetation of polluted and remote areas of both hemispheres—Part I. Its formation, uptake and distribution’, Atmos. Environ. 35, 4511–4521.CrossRefGoogle Scholar