Ecotoxicity and genotoxicity relating to fish in wastewaters discharged from the Vilnius treatment plant

The toxicity and genotoxicity of untreated raw (RWW) and treated wastewaters (TWW) samples from Vilnius wastewater treatment plant was assessed using fish (rainbow trout) at different stages of development. The survival of larvae and fish exposed to RWW in short-term and longterm tests reduced, whereas gill ventilation frequency, heart rate and relative body mass increase of larvae decreased significantly. The long-term exposure of fish to TWW induced significant decreases in white blood cell count and significant increases in micronuclei in blood of treated Oncorhynchus mykiss. The physical, chemical analysis of oil products (C₁₄-C₂₈), benzo(a)pyrene, suspended solids, and heavy metals (Pb, Cd, Zn, Cu, Hg) in RWW demonstrated that the concentrations of xenobiotics and some heavy metals did not exceed their Maximum Permissible Concentrations in the sewerage system and concentrations of substances in TWW corresponded to their criteria for effluents discharged into receiving waters.