Effects of Wastewater Irrigation on Soil Quality and Heavy Metal Contamination in Radish Cultivation

Abstract

This study investigated the effects of wastewater irrigation on soil quality and heavy metal contamination in radish (Raphanus sativus) cultivation in Sargodha, Pakistan. Soil, irrigation water, and radish samples were collected from agricultural fields irrigated with canal water and untreated sewage water. Physicochemical characteristics of water and soil were determined to evaluate salinity, alkalinity, nutrient status, and their influence on metal mobility. Concentrations of Cd, Pb, Cr, Ni, Zn, Cu, Fe, Mn, Co, and Mo were analyzed using Flame Atomic Absorption Spectrophotometry following standard digestion procedures. Results revealed significantly higher electrical conductivity, sodium adsorption ratio, and residual sodium carbonate in sewage water compared to canal water. Sewage irrigation markedly increased soil salinity, organic matter content, and nutrient levels. Heavy metal concentrations were consistently higher in sewage-irrigated water and soils, indicating progressive accumulation. Radish samples grown under wastewater irrigation showed elevated metal levels compared to canal-irrigated crops. Statistical analyses confirmed irrigation source as the primary factor influencing soil quality and contamination patterns. The findings demonstrate that while wastewater irrigation enhances nutrient availability, it significantly contributes to heavy metal enrichment in agricultural soils and radish crops. Continuous monitoring and management strategies are required to ensure sustainable radish production and environmental protection.

Keywords: Wastewater irrigation, Soil quality, Heavy metals, Radish cultivation, Environmental contamination