Evaluation of pollution indices for Cadmium, Lead, and Chromium in water and soil around three rivers in the southwest region of Bangladesh

• Cadmium, lead, and chromium were evaluated in water and soil to ascertain the ecological condition. • Highly sophisticated inductively coupled plasma mass spectrometry (ICP-MS) was utilized. • Near industrial zones elevated amounts of Pb (16.7 µg/L) were observed. • Several indices were used to assess pollution severity. • Ecological Risks were found to be low, except for one soil sample. Environmental health is a significant concern around the world including Bangladesh. In this study, the concentration of toxic Cadmium (Cd), Lead (Pb), and Chromium (Cr) in the water and adjacent soils of the Voirob, Rupsha, and Moyur rivers in the southwest region of Bangladesh, especially the Khulna Metropolitan Area, was investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The Cd, Pb, and Cr levels in the studied samples were measured after digestion and dilution. Then, an integrated pollution evaluation was conducted using several pollution indices, including the Single Factor Pollution Index, Metal Pollution Index, Geo-accumulation Index, Contamination Factor, Pollution Load Index, and Ecological Risk. Substantial amounts of Pb were found in several samples, both the water and soil of the Voirob and Moyur rivers. For example, the amount of Pb in water reached 16.7 µg/L (Sample 20, Moyur river) and in soil reached 615 mg/L (Sample 4, Voirob river), especially near industrial zones. In addition, only Cd showed ecological concern for the single sample. However, all the samples showed minimal ecological danger. From a chemical engineering perspective, the results quantify loading and identify critical pollution areas that require targeted effluent control and remediation strategies. However, they are limited to pre-monsoon sampling and do not include source apportionment modeling with statistical analysis. The study provides valuable insights (dataset) for assessing safety and effective environmental management strategies in the region.