Investigating the risk of heavy metal contamination in an industrial and a non-industrial zone in Gazipur district, Bangladesh

Heavy metal contamination has become a significant public health concern, particularly in rapidly industrializing and developing countries such as Bangladesh. Chronic exposure to toxic metals can cause serious health effects like cancer, cardiovascular disease, and kidney and liver failure. This study aims to evaluate the pollution level and associated health risks of heavy metal contamination in both industrial and non-industrial zones of the Turag River area in Gazipur District, Bangladesh. A total of 36 samples of soil and water were collected from 18 locations, covering both industrial and non-industrial zones from the Turag River. Five heavy metal concentrations, including arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), and copper (Cu), were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Spatial mapping, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were conducted to identify the hotspot region, find possible sources, and categorize the metals or sites having a similar pattern. Pollution levels were evaluated using indices including the geo-accumulation index (Igeo), contamination factor (CF), pollution load index (PLI), heavy metal pollution index (HPI), and ecological risk factor (Er). Additionally, health risks were measured using the hazard index (HI) and the total cancer risk over lifetime (LCR). Our study reported that heavy metal concentrations in soil and water followed the order Cr > Cu > Pb > As > Cd in both zones, while industrial water samples showed Cu > Cr > Pb > As > Cd. In the industrial zone, the mean ± SD concentration of Cr in soil was found to be 52. 22 ± 41. 89 mg/kg, and Cu in water was found to be 1. 70 × 10^ (-2) ± 1. 0 × 10^ (-2) mg/L. The Igeo index indicated that Cd and Cu ranged from uncontaminated to moderately contaminated in both zones. Similarly, the CF and PLI indices showed low to moderate pollution levels from all types of metals, while Cu in industrial water showed a high level of pollution with a CF value of 8. 52. Er values show that Cd and Cr pose a moderate ecological risk in both zones. All the pollution indices for most of the metals showed higher values in the industrial zone compared to the non-industrial zone. Moreover, carcinogenic risks were found for children in both zones, especially for Cr and As in soil. The results highlighted that heavy metal contamination and related health risks were more severe in the industrial zone, posing a significant threat to public health, particularly among children. Strict regulations and law enforcement on industrial emissions are essential to mitigate the risks.