Some important physico-chemical properties of surface water around DEPZ industrial area, Savar were studied to evaluate the water quality. Seven water samples were collected from major waterbodies of DEPZ industrial area. The value of Physico-chemical parameter such and Cr (0.615-0.055 mg/L) were gradually decreased from point source to the remote area. Point source (W 1 ) waterbody had the highest concentration of Cr (0.615 mg/L) which exceeded the safe limit for industrial wastewater. This may be due to various chrome agent used in dyeing purposes. Anionic parameters like F -and PO 4 3-were at intolerable limit in some waterbody. The coefficient of correlation analysis among physicochemical properties indicated that all the parameters had significant contribution to pollute the water. The correlation between DO and pH was strongly negative (r=-0.995**). Fe showed positive significant correlation with Zn, Cu and Cr. There was a significant positive interaction of PO 4 3-with Cl -and NO 3-in case of water quality deterioration. The above findings showed that the surface water around DEPZ industrial area was highly polluted by the industrial activities and was harmful for life.

The present study was carried out to determine the physicochemical parameters of industrial effluents and to find out suitable macrophytes in removing metals from wastewater in order to enhance surface water treatment systems. The effluent samples, effluent free water and aquatic macrophytes were collected from Savar region. Higher values of temperature (56°C), pH (12.32), electrical conductivity (12375 ?S/cm), biochemical oxygen demand (835 mg/L), total suspended solids (2187 mg/L), total dissolved solids (6952 mg/L), turbidity (89.53 NTU) and total organic carbon (421.6 mg/L) were recorded in industrial effluents comparing with control. The lowest concentration of DO in industrial effluents (0.12 mg/L) was much lower than the control (5.65 mg/L). The concentration of Cr (0.69 mg/L), Se (0.08 mg/L), Pb (0.23 mg/L) and Cu (0.71 mg/L) in the effluent exceeded the limit of DOE. Although the concentration of Cd (0.017 mg/L), Li (0.019 mg/L), Ni (0.7 mg/L) and Zn (0.38 mg/L) of effluent water were within the limit of DOE, but were much higher than the control water. The cultures of aquatic macrophytes, Eichornia crassipes, Pistia stratoites and Salvinia cucullata using textile-dyeing effluent can efficiently uptake metals from the effluent. The uptake of metals increased with raising effluent concentration in relation to control culture. When cultured in 100% effluent, Eichornia crassipes, Pistia stratoites and Salvinia cucullata can uptake relatively high amount of Cr, Cd, Cu, Li, Ni, Zn, Co, Se and Pb compared to other two cultures (control, 50% effluent). At 100% effluent water, Eichornia crassipes and Pistia stratoites can uptake more than 90% Co and 80% Se and Pb with low survival capacity. Salvinia cucullata can efficiently absorb Cr, Cd, Li, Ni and Pb with long time survival capacity. While individually Pistia stratoites is more effective in absorbing Cu, Zn and Eichornia crassipes for absorbing Co and Pb in order to enhance surface water treatment system. Bangladesh J. Sci. Ind. Res. 48(2), 89-96, 2013 DOI: http://dx.doi.org/10.3329/bjsir.v48i2.15738

The study was carried out to assess the impacts of textile effluents on aquatic plants by using hydroponic culture. Effluent water of three textile industries and effluent free water were collected from Savar region. The higher contents of pH (10.47), total suspended solids (1407.33 mg/L), total dissolved solids (19014 mg/L) and biochemical oxygen demand (735 mg/L) were recorded in industrial effluents comparing with control. The lowest content of DO in industrial effluents (0.87 mg/L) was much lower than the control (5.65 mg/L). Hydroponic test showed that 100, 75, 50, 25 and 1% textile effluents caused the death of Pistia stratiotes L. and Ludwigia adscendens L. within 1-4, 2- 6, 3-9, 5-12 and 14-17 days, respectively. When P. stratiotes was grown in 100% effluent water its concentrations of Cr, Cd, Cu, Mn, Ni and Zn were 8.00, 1.4375, 189.06, 1843.1, 5.075 and 261.87 ppm, respectively and the test species died within 1 - 3 days. When L. adscendens was grown in 100% effluent water, its concentrations of Cr, Cd, Cu, Mn, Ni and Zn were 7.25, 0.975, 312.87, 1621.2, 5.0125 and 138.75 ppm, respectively and the test species died within 2-4 days. The uptake of heavy metals increased with raising effluent concentration comparing with control culture. The uptake of Cr, Cd, Cu, Mn, Ni and Zn were significantly higher at 50%, 75% and 100% (p = 0.01** at 1% level of significance) effluent which caused the death of both test species. Key words: Textile effluents; Pistia stratiotes L.; Ludwigia adscendens L.; Hydroponic culture. DOI: 10.3329/bjsir.v45i1.5172 Bangladesh J. Sci. Ind. Res. 45(1), 9-16, 2010