Pendimethalin in surface waters of rivers in the proximity of irrigated paddy fields by solid phase microextraction and gas chromatography

The aim of this study was to develop an analytical methodology for the determination of the herbicide pendimethalin in river waters in the towns of Turvo and Meleiro in the southern region of Santa Catarina State, Brazil. The method, based on solid phase microextraction (SPME) followed by separation and detection by gas chromatography (GC) and electron capture detection (ECD), respectively, was optimised and validated. The limits of detection (LOD) and quantification (LOQ) of 0.02 and 0.06 mu g L-1, respectively, and recovery values in the range of 86.2 (+/- 11.5)% to 103.4 (+/- 9.5)% were obtained. It was verified that 53 river water samples showed contamination by pendimethalin at levels that ranged from 0.06 to 0.38 mu g L-1.