Chemical distribution of trivalent iron in riverine material from a tropical ecosystem : A quantitative EPR study

• Published in: Water research (Oxford) 1999-08, Vol.33 (11), p.2726-2734
• Main Authors: OLIVIE-LAUQUET, G, ALLARD, T, BENEDETTI, M, MULLER, J.-P
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biological and medical sciences; Cameroon; Cameroon, Nyong R; Continental surface waters; Earth Sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; Exact sciences and technology; Fresh water environment; Fundamental and applied biological sciences. Psychology; Geochemistry; Mineralogy; Natural water pollution; Pollution; Pollution, environment geology; Sciences of the Universe; Silicates; Water geochemistry; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(98)00479-5

Distribution of trivalent iron has been measured in riverine materials from a tropical hydro-system (Nyong basin, South Cameroon, central Africa). The speciation and the respective amounts of the iron species have been determined using electron paramagnetic resonance spectroscopy on freeze-dried samples separated by ultrafiltration. Trivalent iron occurred mainly in two forms, linked to organic matter (Fe-OM) and as iron oxides. In the Nyong, Fe occurred mainly as oxides (82%), while in the Mengong, a minor river, it was mainly linked to organic matter (64%). This indicates that iron in suspended matter results from mechanical erosion in the main river and from chemical erosion in the minor river. Moreover, the similar size distribution of Fe-OM in both rivers suggests a conservative inheritance of organics-mediated transport of iron in the hydrographical network.