Pesticide occurrence in the waters of Jucar River, Spain from different farming landscapes

A combinedmethodology to identify and quantify farming chemicals in the entire Jucar River basin has been developed. The procedure consisted of the application of environmental forensic criteria associating laboratory analytical samples, cartographic analysis using Geographical Information Systems (GIS) and synthetic statistical analysis. Sampling involved the collection of 15 samples in surface waters distributed alongside the Jucar River and its two main tributaries (Cabriel and Magro Rivers). The analytical procedure involves generic sample extraction and selective determination of up to 50 target pesticides by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Geographical analysis was performed by mixing both sampling points with analytical results and land use-cover layers for the year 2011. PCA and descriptive statistical analysis was further performed combining land use/cover information and pesticides results to determine correlation between dominant agricultural practices ( irrigation and rain fed farming) and location of sampling points. Out of 50 pesticides, 20 were identified and 18 presented concentrations higher than the limits of quantification in surface waters, with a large dispersion in concentrations: from 0.05 ng/L (terbuthylazine-2 hydroxy) to 222.45 ng/L (imazalil). Statistical analyses reveals that there is a correlation between the percentage of land devoted to irrigation farming, whereas correlations are weaker when analysing the relationship of pesticides in rain fed dominated areas. (C) 2017 Elsevier B.V. All rights reserved.