The impact of preload on the mobilisation of multivalent trace metals in pyrite-rich sediment
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Trace metals occur at various concentrations in all wetlands. Their proliferation, chemical speciation, mobility and bioavailability are dependent on the redox potential (Eh), pH and the presence of organic and inorganic adsorption surfaces and co-precipitating metals. Consequently, changes in these key parameters have the potential to alter the fate of the dominant trace metal species in the sediment. An imposition of preload surcharge is a technique use in geotechnical engineering to improve in the strength and load carrying capacity of waterlogged sediments. The soil strength improvement is effected through the expulsion of porewater from the sediment. The imposition of surcharge over wetland sediments has the potential to create oxygen-deficient condition within the sediment, and cause pH, temperature, redox, EC and salinity changes in the sediment, which would impact on the mobilisation, chemical speciation, mobility and bioavailability of dominant toxic trace metals and their toxicity in the sediment. In the present work, a case study of the impact of preload surcharge on the proliferation, chemical speciation, mobilisation, mobility and bioavailability of arsenic, chromium, cobalt, copper and zinc in a naturally occurring pyrite-rich sediment is presented. The imposition of preload surcharge over the pyrite-rich sediment was accompanied by changes in the redox dynamics of the sediment, with multi-facet impact on the concentration, mobilisation and bioavailability of toxic trace metals, their redox transformation between oxidation states and on the toxicity within and outside the sediment environment.
KeywordsMultivalent Trace metals Toxicity Bioavailability Preload surcharge Pyrite-rich sediment
This research was founded by the Maiden Geotechnics and Australian Commonwealth Scholarship awarded by the University of South Australia to the first author.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Amery, F., Degryse, F., Cheyns, K., De Troyer, I., Mertens, J., Merckx, R., & Smolders, E. (2008). The UV- absorbance of dissolved organic matter predicts the fivefold variation in its affinity for mobilizing Cu in an agricultural soil horizon. European Journal of Soil Science, 59, 1087–1095.CrossRefGoogle Scholar
- Clesceri, L. S., Greenberg, A. E. & Eaton, A. D. (eds.) 1998. Standard Methods for the Examination of Water and Wastewater. APHA, AWWA, WEF.Google Scholar
- Johnson, S. J. (1970). Foundation precompression with vertical sand drains. Journal of the Soil Mechanics and Foundations Division: American Society of Civil Engineers, 96, 145–174.Google Scholar
- Karikari-Yeboah, O. & Gyasi-Agyei, Y. (2000). Stability of slopes characterised by colluvium: investigation, analysis and stability. GeoEng2000. Melbourne, Australia.Google Scholar
- Karikari-Yeboah, O., Skinner, W. & Addai-Mensah, J. (2016). The behaviour of reactive toxic solutes in naturally occurring pyrite-rich sediment under surface surcharge. Chemeca Adelaide, Australia.Google Scholar
- Mertens, J., & Smolders, E. (2013). Zinc. In B. J. Alloway (Ed.), Heavy metals in soils—trace metals and matalloids in soils and their bioavailability. Dordrecht: Springer.Google Scholar
- Miller, S. D., Robertson, A., & Donohue, T. (1997). Advances in acid drainage prediction using the net acid generation (NAG) test. In: Proceedings of the Fourth International Conference on Acid Rock Drainage, Vancouver, pp. 535–549.Google Scholar
- Nagpal, N. K. 2004. Water quality guidelines for cobalt. . In: Water Protection Section, W., Air And Climate Change Branch, Victoria; BC (ed.). BC, Canada.Google Scholar
- Oorts, K. (2013). Copper. In B. J. Alloway (Ed.), Heavy metals in soils—trace metals and metalloids in soils and their bioavailability. London: Springer.Google Scholar
- Stewart, W. A., Miller, S. D. & Smart, R. 2006. Advances in acid rock drainage (ARD) characterisation of mine wastes. In: (ED.), R. I. B. (ed.) 7th international conference on acid rock drainage (ICARD) St. Louis MO, 2006, 2098, 2119.Google Scholar
- WHO (ed.) 2001. Environmental health criteria for arsenic and arsenic compounds—EHC 224, Geneva.Google Scholar