Genotoxicity evaluation of different types of leachate treated with Aspergillus flavus using Vicia faba micronucleus

In this study, the efficiency of Aspergillus flavus (A. flavus) was studied in the treatment of three landfill leachate types, namely young, intermediate and old (YL, IL and OL) in terms of removal of organic and nitrogen matter, as well as genotoxicity. The organic fraction of landfill leachate was measured by biological oxygen demand (BOD5) and chemical oxygen demand (COD), and the nitrogen fraction was measured by ammonium (NH4+). The genotoxicity was evaluated using the Vicia faba root-micronucleus test. The analysis of the three leachates revealed high values of COD ( 9517.4-19 523.33 mg/L), BOD5 ( 1756.8-11 600 mg/L), NH4+ ( 5931.25-3112.68 mg/L) and total chromium (CrT: 0.06-3.78 mg/L). The three leachates also showed genotoxic effect on Vicia faba cells at a 1% leachate concentration. The treatment of leachates with A. flavus led to considerable reduction of pollutant load, and it was found to be more effective in reducing COD (30.12 %) and BOD5(71.29%) in YL and NH4+ (98.21%) in IL after 30 days of treatment. A decrease in Micronucleus frequency (48.57-52.32 parts per thousand) was observed in Vicia faba cells exposed to treated OL and IL compared to raw samples, while no such reduction was observed in the treated YL. The treatment of leachate with A. flavus showed more efficiency in genotoxicity removal for OL and IL. However, treated YL still possesses genotoxic character, even if it recorded the highest COD removal rate. Thus, the evaluation of leachate bioremediation on genotoxicity removal effectiveness should be included in landfill leachate risk assessment studies in order to ensure safe levels for its disposal in the environment. (C) 2020 Elsevier B.V. All rights reserved.