Effects of effluent wastewater in developing zebrafish (Danio rerio)


Traditional wastewater treatment is known not to be specifically designed to eliminate the new generation of chemical residues that ends up in the sewage system. Polluted wastewater effluent therefore reaches the aquatic environment possibly causing adverse effects in aquatic wildlife. The effects of effluent water from five Swedish sewage treatment plants sampled on 6 occasions 2017, were studied in developing zebrafish (Danio rerio). The study included morphological, physiological and behavioural endpoints. Overall there were few effects where deviations from control animals could be seen in the exposed zebrafish. The overall outcome of this assessment was that the wastewater effluent had no consistent effects on the early development of zebrafish. The consequences of continuous low-level exposure during the whole life-cycle of wild fish are presently unknown and further studies are needed to evaluate potential risks.