Spatial Analysis of Lead (Pb) Contamination in Soils of the Savar Industrial Zone, Bangladesh Using QGIS-Based Interpolation

Zerin Tasnim, Md. Main Uddin Miah, Quamrun Nahar, Shamima Nasrin, Fariha Islam

Lead (Pb) contamination poses significant environmental and public health risks in industrial regions. This study employs Geographic Information Systems (GIS) to assess the spatial distribution of Pb in soils across the Savar industrial zone, Bangladesh—an area characterized by dense industrial activity, including tanneries, textile mills, and metal-processing plants. Using point data from ten geo-referenced sampling sites, Pb concentrations ranged from 35.6 to 46.0 mg/kg, with a mean of 41.15 mg/kg and standard deviation of 3.53 mg/kg. Inverse Distance Weighting (IDW) interpolation in QGIS was used to create a continuous raster surface of Pb concentrations, revealing notable spatial heterogeneity. High-concentration hotspots (>43 mg/kg) were observed predominantly in the northeastern and central sub-regions, coinciding with mapped industrial clusters. The most contaminated zone (Site 10: 46.0 mg/kg) lies within 500 meters of major manufacturing units, while the lowest (Site 1: 35.6 mg/kg) is situated near peri-urban green space. The resulting contamination map emphasizes localized risk zones and informs targeted remediation efforts. These findings highlight the utility of GIS-based interpolation for environmental risk assessment and land use planning in rapidly urbanizing industrial corridors.