Investigation of the possible sources of heavy metal contamination in lagoon and canal water in the tannery industrial area in Dhaka, Bangladesh

This study evaluated the heavy metal pollution level of tannery effluent-affected lagoon and canal water in the southwestern Dhaka, Bangladesh. The measured physicochemical parameters (electrical conductivity, chemical oxygen demand, pH, SO²⁻₄, PO³⁻₄, Cl-, and NO⁻₃) and metals (As, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, and Zn) were subjected to principal component (PCA) and hierarchical cluster analyses, and examining correlation matrix as well in order to explain the behavior and sources of the parameters/metals. The mean concentrations of the heavy metals in the lagoon and canal water were very high and, in most cases, exceeded the standard limits recommended by the Bangladesh Government. The following elemental associations were obtained from PCA and CA: Ca-Cd-Cr-Fe-K-Mn-Pb-Zn, Co-Cu-Ni, and As,…