Pollution assessment and heavy metal determination by AAS in waste water collected from Kushtia industrial zone in Bangladesh

Abstract

This study was to investigate the contamination level of waste water in the Kushtia industrial region of Bangladesh. Some parameters of waste water were analyzed like pH, electrical conductance, total dissolved solids (TDS), hardness, biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), and for heavy metal (Pb, Cd, Cr, Cu, Mn) concentration. The pH was found to be of range from 8.485 to 4.187; whereas, the electrical conductance was 8.4×10^-4 to 2.9×10^-3 ohm^-1cm^-1. In addition, the lowest value of TDS was 567 and the highest was 956 ppm. Furthermore, the hardness was 848 to 485 mg/l as CaCO₃. Besides, at 20°C, the BOD values were evaluated from 57 to 88 ppm. The COD values retained were from 150 to 108 ppm. In contrast, heavy metals (Pb, Cd, Cr, Cu and Mn) were analyzed and compared with standards of drinking water. The results indicate that the concentration of Mn (0.68 to 0.72 ppm) exceeded the standards, although Pb and Cu were found within the standard limit at 0.0045 to 0.0085 and 1.33 to 1.58 ppm, respectively. Interestingly, contamination of Cd and Cr identified were below detective level. This study points out the health risk status of waste water for residents and aquatic living being, an ultimate concern for their survival in the region.

Keywords: Waste water, pollution assessment, physico-chemical parameters, atomic absorption spectrophotometer (AAS), heavy metal contamination