In vitro effects of wastewater treatment plant effluent on sea bass red blood cells

Red blood cells of marine fish have been used in suitable biological assays to study the (eco)toxicity of wastewater treatment plant effluents. The aim of the present work was to draw upon their more relevant effects on cell hemolysis, ATP content, osmotic resistance and cell volume regulation. Following physico-chemical treatment, treatment plant effluents showed a residual toxicity resulting from multiple impairment of cell metabolism and structures. The earliest and most sensitive effects were related to the regulation of intracellular osmotic pressure leading to decreased cell water volume. Such effects were also observed following short-term incubation in 10-fold diluted effluent. Other damages were found following incubation in non-diluted effluent. Membrane structure was affected leading to increased osmotic resistance. Later, a decrease of the intracellular ATP level was found, followed by hemolysis. The presence of glucose in the incubation medium lessened the fall in ATP content and hemolysis in the treated cells but also in control cells.