Effect of Cow Dung and Urban Waste Compost in Reducing the Accumulation of Cadmium (Cd) and Lead (Pb) in Amaranth Grown in Contaminated Soil

Abstract

Aims: The effect of cow dung and urban waste compost on the capacity of amaranth to absorb cadmium and lead was studied in contaminated soil. Study Design:  Amaranth was cultivated in pot trials randomized blocks with five treatments and four replications for each treatment: control; contaminated soil; contaminated soil with cow dung; contaminated soil with compost and contaminated soil with cow dung and compost. Place and Duration of Study: The trial was carried out in laboratory conditions in the Research Institute for Applied Sciences and Technologies in Ouagadougou from march to April 2022. Methodology: Lead and cadmium concentrations in amaranth leaves and stems was determined using atomic emission spectrometry (MP-AES) after acid digestion. Results: The results showed that contaminated soil with 5 mg kg-1 of lead and 0.2 mg kg-1 of cadmium had no significant effect on amaranth growth. In the dried leaves, mean cadmium levels were 93.5 mg kg-1 in the absence of cow dung and 4.14 mg kg-1 in the presence of cow dung. Mean cadmium levels in dry stems were 64 mg kg-1 and 2.1 mg kg-1 respectively in the absence and presence of cow dung. Lead uptake did not vary significantly in the presence of amendments (0.44 mg kg-1) or in absence of amendments (0.75 mg kg-1) in the stems. The cow dung treatment was more effective than the compost treatment. However, our results showed that the two amendments reduced cadmium transfer by 90% and lead transfer by 70% to amaranth.