Water Quality Assessment of an Industrial Zone Polluted Aquatic Body in Dhaka, Bangladesh

Abstract

Water quality in the aquatic body of Dhaka Export Processing Zone (DEPZ) area was studied on the basis of some physiochemical parameters and heavy metal concentrations. Physiochemical parameters like pH, Electrical Conductivity (EC), Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS) and concentrations of some heavy metals like As, Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb, Hg and Zn were measured. Among different physiochemical parameters, pH, TDS and EC were found within the range. The range of pH for all of the samples was found from 7.1 to 8.17 and 120 to 450 mg/L for TDS. The Values of EC were found from 90 to 300 µs cm-1. For pH, EC and TDS, though the ranges were within the limits but there was an increasing trend of the values was observed in every case which is highly alarming. The range of COD values was estimated from 90 to 300 mg/L and in most of the samples the values exceeded the standard range. The heavy metal containments of the surface water indicated that the concentrations of Cr, Cu, Ni, Zn, Hg and As were obtained below the permissible limit, detection by WHO, 1996. On the other hand, concentrations of Cd, Co, Fe, Pb, Mn and Hg were exceeded the permissible limits. Correlation matrix shows a significant correlation among Pb, Cu, Co, Mn and Fe. Enrichment factor shows high concentrations of Cd, Cr and Hg. Stated environmental condition is highly vulnerable for human being, that's why this is the time to take proper steps for remediation and preventing the pollution around DEPZ water body which is directly related to the industrial emission of DEPZ.