Pesticide Contamination of Surface Water in Egypt and Potential Impact

Enzyme-immunoassay field kits and capillary gas chromatography with nitrogen-phosphorous and electron capture detection (NPD and ECD) systems were used to determine the levels and distribution of commonly used pesticides (alachlor, atrazine, butylate, cyanazine, diazinon, metolachlor, metribuzin, malathion, parathion, propachlor, pendimethalin, trifluralin) and some of their metabolites (diethyl aniline, hydroxy alachlor, DE-atrazine, and DIP-atrazine) in surface water in Egypt. Replicate water samples were collected from several sampling sites near Cairo, Alexandria, Damietta, and Manzala Lake, using solid-phase concentration onto C18 cartridges, and the extract was subsequently analyzed using GC/NPD and GC/ECD systems. Alachlor, metolachlor, trifluralin, parathion, malathion, atrazine, and metribuzin were the most frequently detected pesticides, in the order listed, at the four sampling locations. Alachlor had the highest concentration detected (165-254 ppb), followed by metribuzin (0.6-47 ppb), metolachlor (6.6-12.5 ppb), atrazine, (2.5-7.3 ppb), and malathion (1.5-5.7 ppb). The concentrations of pesticides detected at Cairo were generally lower than those at the other three locations, down stream on the Nile River. The largest number of pesticides detected was in the Damietta branch of the Nile, and their concentration was generally higher than those detected at all other locations. Manzala Lake is the second highest location in terms of overall frequency and concentration of pesticides detected. The ecological and environmental health impacts of such contamination will be discussed.