Abstract

Goal: to detect both known and unknown pesticides and their transformation products in the environment The high-resolution accurate mass Thermo Scientific QExactive instrument in combination with the UltiMate 3000 UHPLC and Thermo Accucore aQ separation column, has for us proven a very robust setup for the screening of 850 pesticides and degradation products with unknown and known retention times in soil, water and food of plant origin. The screening method, with quantification, is used routinely for our research projects. Our screening method covers almost all the pesticides used in Norway. Exceptions are e.g. glyphosate, acidic herbicides and a few biopesticides and growth regulators which require adapted analysis methods, and some pesticides that can only be measured by GC-MS.

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Abstract

Pesticides in agricultural surface water runoff cause a major threat to freshwater systems. Installation of filter systems or constructed wetlands in areas of preferential run-off is a possible measure for pesticides abatement. To develop such systems, combinations of filter materials suitable for retention of both hydrophilic and hydrophobic organic pesticides were tested for pesticide removal in planted microcosms. The retention of six pesticides frequently detected in surface waters (bentazone, MCPA, metalaxyl, propiconazole, pencycuron, and imidacloprid) was evaluated in unplanted and planted pot experiments with novel bed material mixtures consisting of pumice, vermiculite, water super-absorbent polymer (SAP) for retention of ionic and water soluble pesticides, and synthetic hydrophobic wool for adsorption of hydrophobic pesticides. The novel materials were compared to soil with high organic matter content. The highest retention of the pesticides was observed in the soil, with a considerable translocation of pesticides into the plants, and low leaching potential, in particular for the hydrophobic compounds. However, due to the high retention of pesticides in soil, environmental risks related to their long term mobilization cannot be excluded. Mixtures of pumice and vermiculite with SAP resulted in high retention of i) water and ii) both hydrophilic and hydrophobic pesticides but with much lower leaching potential compared to the mineral systems without SAP. Mixtures of such materials may provide near natural treatment options in riparian strips and also for treatment of rainwater runoff without the need for water containment systems.