Evaluation of Chemcatcher® passive samplers for pesticide monitoring using high-frequency catchment scale data

Publication history: Accepted - 13 September 2022; Published online - 30 September 2022Passive samplers (PS) have been proposed as an enhanced water quality monitoring solution in rivers, but their performance against high-frequency data over the longer term has not been widely explored. This study compared the performance of Chemcatcher® passive sampling (PS) devices with high-frequency sampling (HFS: 7-hourly to daily) in two dynamic rivers over 16 months. The evaluation was based on the acid herbicides MCPA (2-methyl-4-chlorophenoxyacetic acid), mecoprop-P, fluroxypyr and triclopyr. The impact of river discharge parameters on Chemcatcher® device performance was also explored. Mixed effects modelling showed that time-weighted mean concentration (TWMC) and flow-weighted mean concentration (FWMC) values obtained by the HFS approach were both significantly higher (p 0.05). There was little indication that river flow parameters altered PS performance—some minor effects were not significant or consistent. Despite this, the PS recovery of very low concentrations indicated that Chemcatcher® devices may be used to evaluate the presence/absence and magnitude of acid herbicides in hydrologically dynamic rivers in synoptic type surveys where space and time coverage is required. However, a period of calibration of the devices in each river would be necessary if they were intended to provide a quantitative review of pesticide concentration as compared with HFS approaches.This work was funded in part by the Source to Tap project (project reference IVA5018 – http://www.sourcetotap.eu), supported by the European Union’s INTERREG VA Programme which is managed by the Special EU Programmes Body (SEUPB). The work was also part-funded by the FAIRWAY project (project reference 727984 - http://www.fair way-project.eu/). supported by the European Union’s HORIZON 2020 Programme