Micronucleus assay based on Vicia faba roots as a tool to assess the performances of wastewater treatment systems

In order to evaluate the efficiencies of three wastewater treatment systems (WWTS), the micronucleus (MN) on Vicia faba roots (through soil and liquid matrix) and phytotoxicity tests were investigated on six wastewater treatment plants in Morocco. Results showed that genotoxicity decreased significantly and reached about 100%, 93.5% and 89% during activated sludge, infiltration–percolation and natural lagoon processes respectively. On the other hand, activated sludge showed the best phytotoxicity removal with a germination index (GI) exceeding 100% for cress. By contrast, infiltration–percolation and natural lagooning systems showed a GI of less than 80%. Using redundancy multivariate analyses, toxicity removal was linked to the abatement of COD, TSS and heavy metal. Thus, genotoxicity assessment based on V. faba roots using liquid matrix seemed to be more promising to evaluate WWTS efficiencies.”