Tracing pesticide dynamics: High resolution offers new insights to karst groundwater quality

Assessment of LC-QTOF-MS data independent acquisition for quantification and suspect screening of pesticides in agriculture impacted water samples

Assessing the impact of agricultural pesticides, and their potential transformation products, in surface (SW) and groundwater (GW) requires the application of target and screening methodologies to cover the maximum number of species. This research investigates the performance of the data independent acquisition (DIA) mode for the quantification of target compounds and the suspect screening of additional pesticides in SW and GW based on a single chromatographic run. Samples were analysed using a liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) platform, combined with an on-line solid-phase extraction (SPE) step. A suite of fungicides and insecticides, widely employed in intensive viticulture areas, was selected to assess the performance of target and screening methodologies in combination with a database of product ion spectra for more than 700 pesticides. As regards quantification of targets, the method achieved limits of quantification (LOQs) between 2 ng l-1 and 25 ng l-1, with linear responses from LOQs up to 500 ng l-1. Accuracy remained between 70 % and 120 %, based on the use of ultrapure water calibration standards. Suspect screening permitted the identification of 90 % of tested compounds when added to SW and GW at levels above 50 ng l-1, improving the percentage of correct identifications versus those attained operating the LC-QTOF-MS platform in the data dependent acquisition (DDA) mode.

Reshuffling the risk values of pesticides in surface-groundwater systems: Evidence from mining intensity and hydrogeological vulnerabilities

The extensive application of pesticides in agricultural cultivation and crop maintenance has resulted in their widespread occurrence and accumulation across diverse environmental media. This study screened >52 target pesticides occurs in both surface and groundwater, including 16 carbamates, 8 triazines, 6 triazoles, 4 chloroacetanilides, 3 neonicotinoids, 3 pyrazoles, 2 morpholines, and 10 other types of pesticides within the Wulong River Basin, situated on the Shandong Peninsula in China. The target pesticides in surface water ranged from below the limit of quantification (LOQ) to 111.2 ng/L, whereas in groundwater, they ranged from below LOQ to 148.1 ng/L. 63 % (p < 0.05) of the target pesticides follow the migration rule, where the concentration in surface water appears exceeded groundwater. 37 % overcome the pesticide properties and aquifer intrinsic vulnerability and show higher values in groundwater. The risk quotient values for imidacloprid and atrazine exceeded 1 at 86 % of the sampling sites, indicating a high level of chronic ecological risk to aquatic organisms. The assessment of pesticide mixtures posed 15 % to 24 % higher risk levels to aquatic organisms compared to individual pesticides. While the non-carcinogenic risks associated with groundwater across all age groups were below the threshold of 1, there was a significant potential carcinogenic risk, particularly for children, warrants due attention. This study provides a new perspective for the systematic analysis of surface-groundwater systems and identify the exposure potential of pesticides in different water bodies and generate priority levels for risk assessment.