Appraisal of phytotoxicity of heavy metals in radish (Raphanus sativus L.) grown in Sargodha district, Pakistan: A quantitative assessment

Abstract

The freshwater shortage and increased domestic effluents have led the farmers to utilize untreated sewage water for irrigation, owing to population growth and urbanization in Pakistan. Though sewage water contains essential plant nutrients, it is also a foremost source of metal contamination within the food chain. This study aimed to compare heavy metals (Cd, Fe, Mn, Cu, Zn, Pb, Ni, and Cr) contamination in radish (Raphanus sativus L.) grown in soils irrigated with sewage water, tube well water, and canal water in Sillanwali and Sargodha of Punjab, Pakistan. The areas were evaluated for heavy metal contamination using soil quality indices, including contamination factor (CF), enrichment factor (EF), bioconcentration factor (BCF), estimated daily intake (EDI), and hazard quotient (HQ), which were duly computed for the collected samples. The physicochemical properties of the soil and water samples were also analyzed. The results indicated that the sewage-irrigated areas are more vulnerable to risk concerning metal contamination than those located along canals. Metal concentrations in sewage-irrigated areas were significantly higher in the edible parts of the vegetables; sewage water contained and transferred more metals than canal water; hence, it poses increased health and ecological risks. Peak concentrations were observed at site SW1 (sewage water, site 1) and were the lowest at site TW2 (tube well water irrigation, site 2). Since all metal index values fell below 1, it shows that all metal concentrations were within permissible limits.