Comparative analysis of heavy metals toxicity in drinking water of selected industrial zones in Gujranwala, Pakistan

Heavy metal contamination of drinking water, primarily driven by industrial activities, represents a critical challenge, with implications for human health and environmental safety. Gujranwala is an industrial and thickly populated city. The current study aimed to assess and compare heavy metal contamination levels in drinking water from five industrial areas and evaluate their potential impacts on human health. Total 100 water samples were collected and analysed for physicochemical parameters and heavy metals. Zonal variations in heavy metal concentrations revealed that Zone 2 had the highest mean levels of cadmium (0.331 mg/L), lead (0.573 mg/L), chromium (0.164 mg/L), arsenic (0.042 mg/L), and aluminium (0.484 mg/L), while Zone 4 showed elevated mean levels of iron (1.88 mg/L) and mercury (0.259 mg/L). Spearman correlation analysis among heavy metals revealed positive relationships among several heavy metals with As notably showing a strong correlation with Hg (0.701**). Kruskal-Wallis test revealed significant spatial variation (p < 0.05) in parameters like pH, EC, TDS, and heavy metals (Cd, Pb, Fe, Cu, Mn, Al), indicating spatial heterogeneity across zones. Spatial distribution maps also depicted heavy metal elevated concentrations of Cd, Pb, Fe, Cr, As, and Hg exceeding in Zone 2 (Engineering industries zone) and 4 (Iron and steel industries zone). The findings revealed a strong link between elevated heavy metal levels and health risks, including dermatological, respiratory, gastrointestinal, and neurological disorders. This study highlights the need for stricter wastewater management, regular monitoring of drinking water, and policies to address water toxicity in industrial premises and to protect public health.