Evaluation of the genotoxicity potential (by Mutatox™ test) of ten pesticides found as water pollutants in Cyprus

Ten pesticides: aldicarb, aldicard sulfone, aldicarb oxide, carbofuran, propoxur, methomyl, diuron, linuron, alachlor and parathion-methyl, found as water pollutants in Cyprus, were evaluated for their genotoxicity potential with the Mutatox™ test, both directly and after exogenous activation with S9 hepatic enzymes. A dark variant (M169) of the Photobacterium phosphoreum was used as the test organism. Trials were undertaken in triplicate using ground-water spiked with pesticides solutions at testing concentration theoretically corresponding to acute effects of 0.004%, up to a maximum of 2%. All tested pesticides were found to be ‘suspect genotoxic’ directly and after S-9 activation, except for Alachlor which after S-9 activation was found to be ‘genotoxic’ at 30 μg/l. Among the ten pesticides Linuron was found to be ‘suspect genotoxic’ after S-9 activation at the lowest concentration, i.e. 2 μg/l. Genotoxicity after activation with S-9 was demonstrated at a concentration 1–3 orders of magnitude lower than the respective concentration for direct genotoxic effects. Moreover, genotoxicity after S-9 was developed at levels where the acute toxic effects (Microtox™) were ‘non measurable’ to ‘negligible’. The investigation of possible genotoxic effects provides essential information on the impacts of pesticides on the Ecosystem and can contribute to the selection of pesticides with the least possible effects.