Occurrence of pesticides in Spanish surface waters. Analysis by high resolution gas chromatography coupled to mass spectrometry

A general study of the presence of pesticides in Spanish surface waters was carried out. A total of 97 samples were analysed by liquid-liquid extraction followed by HRGC/MS in full scan mode. This procedure allows the detection and identification of several commonly used pesticides at levels of 5–50ng/L. The results obtained are studied with regard to know the most common pesticides found in Spanish surface waters, the percentage of them proposed to be included in the Directive 76/464/EEC and their variability depending on the area (agricultural or industrial) and the period of sampling.