title: Picogram per liter detections of pyrethroids and organophosphates in surface waters using passive sampling.
abstract: Pyrethroids and organophosphates are among the most toxic insecticides for aquatic organisms, leading to annual-average environmental quality standards (AA-EQS) in the picogram per liter range in surface waters. For monitoring purposes, it is therefore crucial to develop very sensitive analytical methods. Until now, it is very difficult to reach detection limits at or below given AA-EQSs. Here, we present a passive sampling method using silicone rubber (SR) sheets for the sampling of ten pyrethroids and two organophosphates in surface waters. An analytical method was developed, optimized and validated for the extraction of the insecticides from the SR sheets by accelerated solvent extraction followed by clean-up on C18 and silica gel and detection with GC-MS/MS in positive ionization mode. Good precision (<20%) and absolute recovery (>50%) was observed for all substances, accuracy was between 66% and 139%. Limits of detection between 6 and 200 pg/L were achieved for all substances in surface waters using average sampling rates for PCBs and PAHs. The lack of substance-specific sampling rates and missing performance reference compounds led to an uncertainty in the concentration estimation of factor three in both directions. In a large field study, comprising 40 environmental samples from nine Swiss rivers, eight out of 12 substances were detected (most frequently: chlorpyrifos, cypermethrin). Most of the estimated organophosphate concentrations were between 0.1 and 1 ng/L, most pyrethroid detections below 0.1 ng/L. Four substances (chlorpyrifos-methyl, cypermethrin, deltamethrin and lambda-cyhalothrin) showed exceedances of their respective AA-EQS in multiple samples, also when the uncertainties in the concentration estimation were considered. As pyrethroid and organophosphate detection by SR passive sampling is very practicable and allows sensitive analysis, it has the potential to become a new tool in the monitoring of non-polar pesticides.
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, 8092 Zürich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Moschet
authors.affiliation: Swiss Centre for Applied Ecotoxicology Eawag/EPFL, 8600 Dübendorf, Switzerland.
authors.forename: Etiënne L M
authors.initials: ELM
authors.lastname: Vermeirssen
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Zurich University of Applied Sciences, Institute of Life Sciences and Facility Management, 8820 Wädenswil, Switzerland.
authors.forename: Remo
authors.initials: R
authors.lastname: Seiz
authors.affiliation: Intercantonal Laboratory Schaffhausen, 8200 Schaffhausen, Switzerland.
authors.forename: Hildegard
authors.initials: H
authors.lastname: Pfefferli
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, 8092 Zürich, Switzerland. Electronic address: juliane.hollender@eawag.ch.
authors.forename: Juliane
authors.initials: J
authors.lastname: Hollender
mesh_terms: D004390:Chlorpyrifos / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004784:Environmental Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D007306:Insecticides / Q000737:chemistry*; D057230:Limit of Detection; D009570:Nitriles / Q000737:chemistry; D010755:Organophosphates / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry*; D011722:Pyrethrins / Q000737:chemistry*; D012016:Reference Values; D015203:Reproducibility of Results; D045483:Rivers; D012822:Silicon Dioxide / Q000737:chemistry; D012997:Solvents; D013557:Switzerland; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; D007306:Insecticides; D009570:Nitriles; D010755:Organophosphates; D010575:Pesticides; D011722:Pyrethrins; D012997:Solvents; D014874:Water Pollutants, Chemical; C017160:cypermethrin; C017180:decamethrin; C013830:baysilon; D012822:Silicon Dioxide; D004390:Chlorpyrifos
keywords: Analytics; Gas chromatography mass spectrometry; Insecticides; Monitoring; Silicone rubber; Surface water