Ecotoxicological Evaluation of Wastewater Samples from Gadoon Amazai Industrial Estate (GAlE), Swabi, Pakistan

Industrial wastewater is a potential source of water pollution and a common threat to aquatic life. Chemical analysis of wastewater quantifies the concentrations of toxic substances but does not reflect their toxic effects on aquatic biota. Therefore, bioassessment is very necessary for monitoring of wastewaters quality. In the present study wastewater samples from Gadoon Amazai Industrial Estate (GAIE), Pakistan, were evaluated for their ecotoxicological effects using the automatic biotest ECOTOX and a Pulse Amplitude Modulated (PAM) fluorometer. Various physiological parameters of the freshwater flagellate Euglena gracilis like motility, swimming velocity, cell shape, gravitactic orientation and photosynthetic efficiency were used as end points. In addition, the water samples were analyzed for some common physicochemical properties. With some exceptions, most of the physicochemicalproperties of thetested sampleswerewithinthe acceptablerange of national environmental quality standards for municipal and industrial effluents (NEQS). However, all the water samples adversely affected different physiological parameters in Euglena gracilis. This study led to the conclusion that different toxic substances present in wastewater, even at low concentrations, adversely affect the physiology of aquatic biota. Gravitactic orientation and cell shape in Euglena gracilis were very sensitive to wastewater toxicity and can be used as reliable end points for wastewater bioassessment.