Benaki Phytopathological Institute, Department of Pesticides Control and Phytopharmacy, Laboratory of Chemical Control of Pesticides, 8 Stefanou Delta Street, Kifissia, Athens, 14561 Greece
Dr. Helen Karasali
Benaki Phytopathological Institute, Department of Pesticides Control and Phytopharmacy, Laboratory of Chemical Control of Pesticides, 8 Stefanou Delta Street, Kifissia, Athens, 14561 Greece
Soil constitutes the central environmental compartment that, primarily due to anthropogenic activities, is the recipient of several contaminants. Among these are organochlorine pesticides (OCPs), which are of major concern, even though they were banned decades ago due to their persistence and the health effects they can elicit. In this review, an overview of monitoring studies regarding OCPs in soils published over the last 30 years along with the development of analytical methods and extraction procedures for their determination in soil are presented. The presented synopsis verifies the soil contamination by OCPs during the last several decades. Soil pollution by OCPs should be an essential aspect of the characterization of whole soil quality, considering that a significant percent of soils on a global scale are in the borderline of suitability for cultivation and pertinent activities. The latter, to an extent, is attributed to the presence of organic contaminants, especially those of persistent chemical natures.
Soil can be contaminated by pesticide residues through agricultural practices, by direct application or through spray-drift in cultivations. The dissipation of those chemicals in the soil may pose risks to the environment and human health. A simple and sensitive multi-residue analytical method was optimized and validated for the simultaneous determination of 311 active substances of pesticides in agricultural soils. The method involves sample preparation with QuEChERS-based extraction, and determination of the analytes with a combination of GC-MS/MS and LC-MS/MS techniques. Calibration plots were linear for both detectors over the range of five concentration levels, using matrix-matched calibration standards. The obtained recoveries from fortified-soil samples ranged from 70 to 119% and from 72.6 to 119% for GC-MS/MS and LC-MS/MS, respectively, while precision values were <20% in all cases. As regards the matrix effect (ME), signal suppression was observed in the liquid chromatography (LC)-amenable compounds, which was further estimated to be negligible. The gas chromatography (GC)-amenable compounds showed enhancement in the chromatographic response estimated as medium or strong ME. The calibrated limit of quantification (LOQ) value was 0.01 μg g−1 dry weight for most of the analytes, while the corresponding calculated limit of determination (LOD) value was 0.003 μg g−1 d.w. The proposed method was subsequently applied to agricultural soils from Greece, and positive determinations were obtained, among which were non-authorized compounds. The results indicate that the developed multi-residue method is fit for the purpose of analyzing low levels of pesticides in soil, according to EU requirements.