Detection of genotoxicity in hospital wastewater of a developing country using SOS chromotest and Ames fluctuation test

Background: Hospitals discharge considerable amounts of chemicals in their wastewaters that may be genotoxic or present serious health hazards. The genotoxic potential of wastewater in a Lebanese University Hospital was evaluated using the SOS Chromotest and the Ames fluctuation test. Different concentrations were tested to determine the recommended dilution for each sample to decrease its genotoxicity. Methods: The samples were taken from 5 different pits, 2 times per day in the morning and in the afternoon during two 1-week (5 days) periods in February and August 2011. SOS Chromotest and the Ames fluctuation were used to test genotoxicity. Results and conclusions: This study revealed that hospital wastewater was mostly genotoxic. 50% of the samples were positive for genotoxicity in the SOS Chromotest and 67.5% in the Ames fluctuation test. Genotoxicity of the sample was affected by the time, day, and season of sample collection. Different pits, representing different wastewater collection points, also varied with respect to the intensity of genotoxicity. Other genotoxic tests are currently underway to further evaluate the toxicity of these samples and to identify the genotoxic com pounds. This study shows that hospital wastewater must be carefully monitored and proper disposal or treatment measures need to be implemented.