Assessment of priority pesticides, degradation products, and pesticide adjuvants in groundwaters and top soils and pesticide adjuvants in groundwaters and top soils from agricultural areas of the Ebro river basin

10 pages, 2 figures, 4 tables.-- PMID: 17211597 [PubMed].-- Printed version published Feb 2007.Gas chromatography-mass spectrometry (GC/ MS) was employed for the determination of 30 widely used pesticides including various transformation products and alkylphenols in water and agricultural soils with the aim of assessing the impact of these compounds in agricultural soils and the underlying aquifer. The extraction, clean-up, and analytical procedures were optimized for both water and soil samples to provide a highly robust method capable of determining target analytes at the ppb–ppt level with high precision. For water samples, different solidphase extraction cartridges and conditions were optimized; similarly, pressurized liquid extraction conditions were tested to provide interference-free extracts and high sensitivity. Instrumental LODs of 3–4 pg were obtained. The multi-residue extraction procedures were applied to the analysis of groundwaters and agricultural soils from the Ebro river basin (NE Spain). Most ubiquitous herbicides detected were triazines but some acetanilides and organophosphorus pesticides were also found; the pesticide additive tributylphosphate was found in all water samples. Levels varied between 0.57 and 5.37 μg/L in groundwater, whereas nonylphenol was the sole compound detected in soil. Alkylphenols are used as adjuvants in pesticide formulations and are present in sludges employed as soil fertilizers. Occurrence was found to be similar to other environmental studies.This research project was founded by the European Union under the Global Change and Ecosystems (FP6) Water Cycle and Soil Related Aspects (AQUATERRA, Project number 505428 GOCE). Financial support from Spanish Ministry of Education and Science (Project number CTM2005-25168-E) is also acknowledged. The authors also thank Waters Corporation and Merck for providing SPE cartridges, as well as Dr. Roser Chaler, Dori Fanjul, and Alicia Navarro for their assistance with GC-MS.Peer reviewe