Assessing heavy metal bioaccumulation in radish and soil under wastewater and canal water irrigation

Abstract

Freshwater resources are continuously depleting over time due to the combination of various climatic, political and anthropogenic factors. The freshwater shortage has compelled farmers to use sewage water as an irrigation source for vegetable cultivation. However, urban sewage water contains a sufficient amount of heavy metals which can easily damage soil, crops and affect human health. The present study compared the concentrations of toxic metals including copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), cadmium (Cd) lead, (Pb) and cobalt (Co) in radish and soil irrigated with sewage water (SW) versus canal water (CW). The results showed that the SW contains a significant number of heavy metals e.g., Cu (1.735 mg/kg), Fe (3.775 mg/kg), Zn (1.885 mg/kg), Mn (0.375 mg/kg), Cd (0.044 mg/kg), Co (0.05 mg/kg), Pb (0.062 mg/kg), and Mo (0.07 mg/kg), leading to increase the accumulation in the radish and soil by increasing their permissible limits. The irrigation water sources also have the potential to affect soil physicochemical properties and proximate composition of the radish. The sewage water irrigation notably increased salinity, nutrients, and soil organic matter, however it also increased the contamination risks. The Pollution Load Index (PLI) and Bio-concentration Factor (BCF) metrics revealed that sewage water has substantial adverse health impacts due to high metal contamination. There is an urgent need to adopt the innovative management strategies to improve the irrigation water sources to prevent soil health threats from metal pollution.