Heavy metal distribution in soils near Palapye, Botswana: An evaluation of the environmental impact of coal mining and combustion on soils in a semi-arid region

Mingzhe Zhai, Otlogetswe Totolo, Motsoptse P. Modisi, Robert B. Finkelman, Sebueng M. Kelesitse, Mooketsi Menyatso

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Morupule Colliery near Palapye in eastern Botswana is the only coalmine in production in Botswana at present. Its coal is mainly used in the nearby coal-fired Morupule Power Station, which generates approximately 1,000 GWh of electricity per annum. After more than 30 years mining and more than 20 years of combustion, the sedimentation of outlet fly ash from the Morupule Power Station has increased concentrations of Cr, Ni, Zn and As by 13, 2.5, 16 and 5 ppm, respectively, in the fine portion (<53 μm) of surface soils for approximately 9 km downwind. Elements that have higher concentrations in coal have stronger small-particle association during coal combustion and are less mobile in surface soils, thus showing stronger contaminations in surface soils around the coal-fired plant. Although the degree of contamination of Cr, Ni, Zn and As from coal combustion in the Palapye area at present is low, it is necessary to monitor concentrations of these elements in surface soils routinely in the future. This study also reveals moderate Pb and Zn contaminations in the Palapye area. The former is due to the use of leaded petroleum in motor vehicle traffic and the latter is mainly due to the use of galvanized iron sheets in construction.

Original languageEnglish
Pages (from-to)759-777
Number of pages19
JournalEnvironmental Geochemistry and Health
Volume31
Issue number6
DOIs
Publication statusPublished - Dec 1 2009

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Water Science and Technology
  • Environmental Science(all)
  • Geochemistry and Petrology

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