Calibration and field validation data to support a simple yet robust implementation of passive sampling methods for...

Passive sampling offers a promising approach for assessing contaminants in surface waters; however, its broader adoption is limited by the need for standardized and user-friendly implementation methods and the availability of suitable sorbents. This study investigates the performance of the widely used Empore™ SDB-RPS disk and two potential alternative sorbent phases-Affinisep AttractSPE® HLB (AHLB) and Biotage Atlantic® HLB-L (BHLB)-for the uptake of >100 pesticides with diverse physicochemical properties (logKOW = -2 to 5, pKa = -3.15 to 12.58) and compares them against the Empore SDB-RPS disk. The passive sampler (PS) performance was evaluated under controlled laboratory settings using a flow system at environmentally relevant conditions (21 cm/s, 300 ng/L, 2-week exposure) and an established open-source stainless-steel housing. Diffusive transport characteristics were assessed by determining relative resistances of the water boundary layer and the sorbent to the mass transfer, with average sorbent resistance (1/Rs, tot) contributions ranging from 39% and 40% (AHLB and SDB-RPS) to 87% (BHLB). Performance under field conditions was assessed through a 2-week calibration alongside active sampling in an agricultural stream (22-40 cm/s). Pesticide accumulation was linear to curvilinear (monotonically increasing) for all PSs, despite uptake being partially (AHLB and SDB-RPS) or almost completely (BHLB) controlled by the sorbent. The uptake of pesticides to all PSs could be well described by a simple first-order uptake model as opposed to more complex approaches, such as incorporating fluctuating water concentrations or diffusion models. Laboratory sampling rates (Rs) could be determined for 78% of pesticides. Comparable results were observed for AHLB (Rs average = 0.42 ± 0.24 L/day) and SDB-RPS (Rs average = 0.41 ± 0.27 L/day), whereas BHLB showed lower rates (on average, a factor of 5 lower). Field evaluations confirmed the similar capabilities of AHLB to SDB-RPS, detecting ≥43 of the studied pesticides, while BHLB detected fewer (29 pesticides), likely due to its fiberglass structure acting as additional resistance. For all sorbents and compounds with available sampling rates (>50% of detected compounds in the field), time-weighted average concentrations derived from PS closely matched active sampling measurements between 0.5 and 2.5 times, supporting their reliability for pesticide quantification. Overall, this study provides recoveries, sampling rates, and sampler-water partition coefficients (Ksw) for three PSs for a range of pesticides. This work helps to facilitate the broader adoption of passive sampling techniques for regulatory and environmental analysis.