Effect of organic and inorganic amendments on lead, zinc and cadmium accumulation in maize grown in contaminated soils in Kabwe (Zambia).
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Date
2022
Authors
Mwilola, Patricia Nalishebo
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Publisher
The University of Zambia
Abstract
In Kabwe, contamination resulting from lead (Pb), Zinc (Zn) and Cadmium (Cd) has led to high concentration of the heavy metals in the soils. These contaminations cause a serious threat to the food chain, mostly through the uptake of these metals by crops such as maize. This study was conducted to assess the effect of phosphate and manure amendments on (1) the immobilization of Pb, Zn and Cd in soils and (2), accumulation of the three heavy metals (HMs) in different maize parts. A randomised complete block design was established where with the following treatments: chicken manure (CM), bio-fertilizer (BF), ammonium nitrate (AN), triple super phosphate (TSP) and the control (CT). The treatments were replicated 4 times. Maize was grown to maturity and the HM concentrations were analysed in roots, stems and grain. The results indicated that TSP was the most effective amendment for immobilization of Pb by 36 %, while CM had the highest potential of reducing the bioavailability of Zn by 19 %, and BF was effective at Cd immobilization in the soil by 4 %. The amendments had different effect on the uptake of HMs in different parts of maize. In the roots, TSP and AN were effective in reducing the concentration of Pb, Zn and Cd, respectively. The amendments that were effective in reducing the concentration of Pb and Zn in the stover were CM; the reduction was 80 % for Pb and 38 % for Zn. Furthermore, for Cd reduction in the stover, BF was the most effective amendment by 61 % compared to the CT. Both the concentration of Pb and Cd in the maize grain was reduced by BF, while CM reduced the concentration of Zn in the grain. BF was the most effective amendment in reducing the concentration of Zn in the grain. Therefore, the people of Kabwe can be advised to use CM or BF amendments in their gardens or fields to reduce the bioavailability of these HMs in the soil, hence reduce the concentration in the crops.
Keyword: Bio availability, amendments, heavy metals, maize, Kabwe.
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Keywords
Bio availability. , Lead contamination. , Contaminated soils--Effect of. , Soils--Heavy metal content. , Soils--Leaching.