Concentrations, fluxes and field calibration of passive water samplers for pesticides and hazard-based risk assessment

Abstract

Three passive sampler types including Chemcatcher® C₁₈, polar organic chemical integrative sampler-hydrophilic-lipophilic balance (POCIS-HLB) and silicone rubber (SR) based on polydimethylsiloxane (PDMS) were evaluated for 124 legacy and current used pesticides at two sampling locations in southern Sweden over a period of 6 weeks and compared to time-proportional composite active sampling. In addition, an in situ calibration was performed resulting in median in situ sampling rates (R_S, L day^-1) of 0.01 for Chemcatcher® C₁₈, 0.03 for POCIS-HLB, and 0.18 for SR, and median in situ passive sampler-water partition coefficients (log K_PW, L kg^-1) of 2.76 for Chemcatcher® C₁₈, 3.87 for POCIS-HLB, and 2.64 for SR. Deisopropylatrazine D₅ showed to be suitable as a performance reference compound (PRC) for SR. There was a good agreement between the pesticide concentrations using passive and active sampling. However, the three passive samplers detected 38 pesticides (including 9 priority substances from the EU Water Framework Directive (WFD) and 2 pyrethriods) which were not detected by the active sampler. The most frequently detected pesticides with a detection frequency of >90% for both sites were atrazine, 2,6-dichlorobenzamide, bentazone, chloridazon, isoproturon, and propiconazole. The annual average environmental quality standard (AA-EQS) for inland surface waters of the EU WFD and the risk quotient (RQ) of 1 was exceeded on a number of occasions indicating potential risk for the aquatic environment.

Keywords: Chemcatcher; POCIS, silicone rubber; Passive sampling; Pesticides; Priority substances.