Remediation of trace metal Contaminated Auto-mechanic soils with Mineral Supplemented-organic Amendments

Chris Nwoko, Chidinma Peter-Onoh, Grace Onoh
unpublished
Trace metal contamination of soil and surface waters arising from increased emissions from industries,traffic, auto-mechanic activities and agriculture raise concern on human health and environmental quality. The aim of this study was to find practical and cost-effective measures to reduce metal uptake in crops grown on metal contaminated soils. A laboratory batch experiment using 6 potential mineral-organic amendment combinations in the ratio 1: 2, (a)composted Farm yard manure (cFYM) + Gravel
more » ... sludge (GrS), (b) Vemicompost (VC) + GrS, (c) composted sewage sludge (cSS)+ GrS , (d) Red mud (RM)+ cFYM), (e) RM + VC, (f) cSS+ RM, were used to treat trace metal contaminated soil in a completely randomized pot experiment using Amaranthus viridis as a test crop. Result showed that all the amendment combinations had varied potential to reduce metal uptake by Amaranthus viridis when compared to control. There was appreciable reduction in metal leachability across all the amendments: Cd (<51%), Cu (<67%), Zn (<34%) and Pb (<69%) on the average when compared to controls, with a concurrent reduction of uptake into Amaranthus viridis root and shoot tissues (Cd < 62%, Pb < 68%, Cu< 66% and Zn 56%) on the average. Dry matter yield in the amendments is in the order cFYM + GrS> cFYM +RM> cSS+GrS>cSS+RM>Control>VC+RM >VC+GrS.Acid extractable (DTPA) fractions of Cd, Pb, Cu and Zn were reduced by up to 76%, 79%, 65% and 49%, respectively in amended soils. Investigations on long term effects of metal mobility is recommended
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