Background: Hospital wastewater is a major source of micropollutants and toxic chemicals. It ends up draining into many aquatic bodies, causing environmental hazards. The aim of the study was to perform genotoxic tests on two major Lebanese University hospitals: Hospital A (300 beds) situated in the city and Hospital B (180 beds) in a rural area.
Methods: Samples from Hospitals A and B were taken from different pits on a 5-day period. Two genotoxic tests were performed: the SOS Chromotest (Escherichia coli PQ37) and the Ames Fluctuation Test (Salmonella Typhimurium TA98) with and without metabolic activation (S9 addition).
Results and conclusions: In Hospital A, 20% of the samples tested by the SOS Chromotest were genotoxic without metabolic activation, whereas around 46% of the same samples were genotoxic after metabolic activation. Similarly, an increase of 25% of genotoxic activity was observed in Hospital A samples using the Ames Fluctuation Test after metabolic activation. On the other hand, wastewater samples from Hospital B tested with the SOS Chromotest showed no or low genotoxicity at the concentrations tested both with and without metabolic activation. Using the Ames Fluctuation test, samples from Hospital B showed slight genotoxicity only after activation. Hospital B implemented a policy of collecting all the excess pharmaceuticals to limit the disposal of harmful chemicals into the drain.
Keywords: Genotoxicity, wastewater, SOS chromotest, ames fluctuation test, metabolic activation