The effects of single and mixed treatments of lead and cadmium on soil bioavailability and yield of Brassica napus irrigated with sewage effluent: a potential human risk

Abstract

The effect of single and mixed treatments of Lead (Pb) and Cadmium (Cb) on soil bioavailability and uptake by Brassica napus was investigated in greenhouse using soil from Golden Ridge Estate and waste water from Pakamisa Sewage Treatment Plant, Gweru, Zimbabwe. Pb and Cd had significant effects on metal soil bioavailability and yield in single treatments. Soil bioavailable Pb in mixed treatments significantly correlated positively with uptake by B.napus. Yield was significantly correlated negatively with soil bioavailable Pb and Cd as well as metal uptake. Soil bioavailable Pb accounted for 49.2%(single treatment) and 6.1%(mixed treatment) of the variation in B. napus yield. Pb uptake accounted for 4.63%(single treatments) and 88.77%(mixed treatments) of the variation in yield.