Evaluation of Surface Water Quality Affected by Industrial Effluents Near Tannery Industrial Area: Heavy Metal Concentrations and Ecological Toxicity Index Measurement

Abstract

Tannery industry is one of the profits making industry in Bangladesh. However, the devastating situation on environmental degradation is occurring at present. Untreated tannery effluents deteriorating the river water quality and hence the ecology and human health. The newly shifted tannery industrial zone in Savar is adversely deteriorating environmental quality of Dhaleswari River. Previously, it was on the bank of Buriganga river which is now become a dead river (DO = 0 mg/L). To find out the current water quality status in Dhaleswari River, present research was planned. Ten water samples (each distance 500 m) were collected and different physicochemical and carcinogenic metals were analyzed. The data showed that EC, TDS, TSS and BOD were found higher than maximum permissible limits. DO was found almost zero (DO = 0.13 mg/L) which is an indication that the river water is in critical stage now. Moreover, the carcinogenic elements such as Cr, Hg, Fe and Mn concentrations of the river water found several fold higher than Bangladesh and WHO standards. The calculated HPI, MI, Cd and PERI data showed that the river water quality is deteriorating tremendously which is unsafe for ecology and human health. Correlation matrix data showed that different pollutants such as Cr showed strong positive correlation with Pb (r = 0.793 and p < 0.01), Hg (r = 0.825 and p < 0.01) and Cu (r = 0.703 and p < 0.05) which indicating that increasing Cr concentration will increase Pb, Hg and Cu concentration and vice-versa. Based on the present research data, the Dhaleswari river water quality is adversely deteriorating by untreated industrial effluents in that area.