Monitoring and Risk Assessment of Organophosphorus Pesticide Residues in Surface and Drinking Water in Some Egyptian Governorates

The aim of this study was to track the presence of 12 organophosphorus pesticides (OPPs) in 144 surface and drinking water samples collected bimonthly in a one-year sampling campaign from the inlet and outlet of 6 drinking water treatment plants (DWTPs) in three Egyptian governorates (El-Kalyoubia, Kafr El-Sheikh, and Alexandria). The lifetime intake of polluted water was also evaluated for any potential non-carcinogenic health consequences. Results revealed that 41.6% and 8.3% of the surface and drinking water samples were polluted with OPPs, respectively. Out of the 12 OPPs analyzed, four were detected in both water samples at various concentrations. The most frequently found OPPs in both water samples were diazinon, followed by prothiofos and chlorpyrifos, which were detected in 13.9%, 5.6%, and 4.2% of samples, respectively. On the other hand, OPP residues did not exceed the maximum residue levels (MRLs). Based on our spatiotemporal monitoring, the detected OPP residues in both water samples collected from the three governorates exhibited fluctuations due to residential, industrial, and agricultural activities along the sampling points. The target hazard quotient (THQ) values for non-carcinogenic pesticide hazards observed in surface and drinking water were less than one. This indicates that drinking water exposure in the study areas poses no risk to humans.