Heavy metal contamination of soil and water from waste landfill sites in the second-largest city of Bangladesh

Abstract

Globally, unregulated waste landfill sites are major sources of heavy metals, particularly lead (Pb), cadmium (Cd), and chromium (Cr), posing serious risks to soil, water, and human health. Comprehensive assessments of landfill-derived heavy metal contamination remain scarce in Bangladesh, particularly in Chattogram City. This study was conducted at two landfill sites in Chattogram (Ananda Bazar and Arefin Nagar) using systematic sampling of soil, irrigation water, and drinking water. The results revealed significant variations in heavy metal concentrations with distance from landfill sites. Soil within 30 m showed the highest Cd (17.17 ppm) and Pb (131.85 ppm) in Ananda Bazar, exceeding WHO standards of 0.8 ppm and 85 ppm, respectively. In irrigation water, Cr concentration was consistently high with a peak of 0.45 ppm at 30 m in Ananda Bazar. Although Pb and Cd concentrations varied significantly, they showed a general decreasing trend with increasing distance. Drinking water in Ananda Bazar showed hazardous Pb (0.06 ppm) concentration surpassing WHO permissible levels (0.01 ppm), while Cr concentration slightly exceeded safe levels in some samples, the Cd remained within safe limits. Significant spatial differences in heavy metal concentrations were observed across most samples (p < 0.05), whereas drinking water samples from Arefin Nagar did not show significant variation (p > 0.05). This pattern emphasizes the risk of localized contamination and the need for regular monitoring and management interventions to reduce further contamination. These findings provide a scientific basis for Chattogram to adopt evidence‑based interventions such as protective well buffers, improved landfill engineering, and routine monitoring to ensure safe and sustainable urban waste management.