Understanding the toxicity of certain potentially toxic compounds on various aquatic organisms allows to assess the impact that these pollutants on the aquatic biota. One source of pollution is the wastewater from hemodialysis. The process of sewage treatment is inefficient in inhibition and removal of pathogenic bacteria resistant to antibiotics in this wastewater. In many countries, such as Brazil, during emergencies, sewage and effluents from hospitals are often dumped directly into waterways without any previous treatment. The objective of this study was to characterize the effluents generated by hemodialysis and to assess the degree of acute and chronic environmental toxicity. The effluents of hemodialysis showed high concentrations of nitrites, phosphates, sulfates, ammonia, and total nitrogen, as well as elevated conductivity, turbidity, salinity, biochemical and chemical oxygen demand, exceeding the thresholds defined in the CONAMA Resolution 430. The samples showed acute toxicity to the green flagellate Euglena gracilis affecting different physiological parameters used as endpoints in an automatic bioassay such as motility, precision of gravitational orientation (r-value), compactness, upward movement, and alignment, with mean EC50 values of recalculate as 76.90 percent (±4.68 percent) of the undiluted effluents. In tests with Daphnia magna, the acute toxicity EC50 was 86.91 percent (±0.39 percent) and a NOEC value of 72.97 percent and a LEOC value 94.66 percent.
Keywords: Bioassay; Daphnia magna; Environmental toxicity; Euglena gracilis; Hemodialysis effluent.
Copyright © 2014 Elsevier Inc. All rights reserved.