Monitoring of Insecticides and Fungicides in Water and Sediment Samples in the Brazilian Environment

Abstract

Immunoassay techniques, either microtiter plate or magnetic particle-based ELISA and various gas chromatographic techniques (GC-ECD, GC-NPD and GC-MS) were applied to the determination of priority pesticides (chlorothalonil, metalaxyl, carbendazim, parathion-methyl and folpet) in water and sediment samples from Paty do Alferes at Rio de Janeiro State (Brazil). Water samples were directly analyzed in the field by immunoassay techniques and transported to Barcelona after being stored in SPE disks. Sediment samples were frozen and transported to Barcelona for further analysis. All results were confirmed by GC-MS under negative chemical ionization and using SIM and the protocol was extended to other pesticides like naled, fenitrothion and azinphos-ethyl that could not be measured with ELISA. The results showed that the majority of the water samples had pesticide levels below 5 ng/l with the exception of chlorothalonil and folpet that showed values up to 114 and 210 ng/l, respectively. The sediment samples showed values of 5–132 ng/g for folpet and one order of magnitude lower for chlorothalonil, being the two pesticides that exhibited the highest persistence in the Brazilian environment.