Holistic assessment of pesticide residues in Irish agricultural soil

Agricultural industry highly dependent on pesticide usage, for boosting efficiency and productivity, however it can result in irreparable damage to the soil layers. Hence, it is essential to understand the current level of pesticide contamination in the Irish agricultural soil. This work focuses on establishing the level of contamination of ten pesticide compounds in the Irish agricultural soil. To obtain a holistic understanding, the determined pesticide concentrations were then correlated with the soil physicochemical properties and microbial activities. The analytical challenges to quantifying pesticides from soil were addressed by comparing QuEChERS and Dutch mini-Luke, where Dutch mini-Luke was determined to be the preferred extraction method for all the targeted analytes as it provides a superior analytical advantage over QuEChERS. In 2021, soil samples were collected from 25 fields, 24 agricultural lands and one commonage land. It was determined that 92% of the collected fields exceeded the parametric limit set for Irish drinking water for five pesticides. Interestingly, neonicotinoids we detected in 24 sites, including one with no history of pesticide application. Additionally, the correlation of total pesticides detected, and soil physicochemical properties indicated that pesticides correlate negatively with soil organic matter and positively with the percentage of clay. To further explore the correlation, the potential relationship between the microbial community and the pesticide concentration was assessed using MicroResp. Although the complete interaction between targeted pesticides and the agricultural soils is not fully understood, these results provide the baseline for a more detailed investigation of pesticides in the Irish soil environment