Establishing to what extent Irish agricultural soils are contaminated with pesticides Vickneswaran, Mathavan 1 , Zioga, Elena 2 , Carolan, James 3 and White, Blánaid 1 1 School of Chemical Sciences, Dublin City University, Ireland, 2 Botany Department, Trinity College Dublin, Ireland, 3 Department of Biology, Maynooth University, Ireland Of all the earth’s resources, none are deliberately modified constantly to suit human needs more so than soil, particularly agricultural soil. In agricultural practice, pesticide application is deemed essential to tackle current or future potential pest infestation. It is of course acknowledged that the usage of pesticides contributes to global food security, but it also presents quite a quandary. Ideally, a pesticide should only affect the targeted pests, but in reality, the resultant pesticide residues have been shown to persist in soil and impact far more widely than was intended. In the global and Irish context, we still have huge gaps in our understanding of how pesticides behave in soil, and how that varies for different soil types and in different environmental conditions. In the first phase of addressing this knowledge gap, the most widely used herbicides, insecticides, and fungicides in Ireland were identified using data provided by the Irish Department of Agriculture. Based on these data, the most widely used herbicides, insecticides and fungicides were prioritised for analysis. In this study, nine widely used pesticides were prioritised, namely the neonicotinoids, fluroxypyr, prothioconazole, glyphosate and AMPA. Subsequently, two different extraction methods were explored with the capability of extracting the targeted multi- residual pesticides from the soil. In the early assessment, the QuEChERS extraction method was ineffective in extracting the pesticide fluroxypyr and prothioconazole, while the Dutch mini-Luke extraction method was successfully validated for the extraction of all the analytes of interest. Successively, 25 Irish agricultural fields with different soil classes were selected to study the level of soil pesticide contamination, where sampling of the soil was carried out within 24-hours and one week of post pesticide spraying. These soil samples were then extracted using Dutch mini-Luke and analysed using a Liquid Chromatography Coupled with Triple Quadrupole Mass Spectrometry (LC-MS/MS), where neonicotinoids, fluroxypyr and prothioconazole were analysed using a C18 column, while glyphosate and AMPA were analysed using a novel HILIC column method. This presentation will explore the extent to which the different pesticides were detected across each soil class, at what concentration and giving rise to what potential hazards. The impact of soil class on persistence and rate of degradation will also be discussed. Ultimately, the findings from this study will help us to fill in the knowledge gap on the behaviour of pesticides in Irish agricultural soils, and assist in developing a soil protection framework ensuring sustainable pesticide usage in Ireland.
IP17
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