Can POCIS be used in Water Framework Directive (2000/60/EC) monitoring networks? A case study focusing on pesticides in a French agricultural watershed

International audienceIn this study, we reviewed the main current limitations in the application of the Polar Organic Integrative Sampler (POCIS) in regulatory monitoring programmes. After a case study focusing on pesticides in a French watershed, we concluded that the POCIS is already well-suited for both operational and investigative monitoring, and proposed a procedure for using passive sampler data for compliance checks in the framework of surveillance monitoring. Regarding surveillance monitoring, uncertainties and sampled fraction issues and then compliance with environmental quality standards (EQS) requirements were addressed. We estimated that the uncertainty related to POCIS data might be up to 138 %, which is higher than European requirements, but we concluded that this issue is adequately counterbalanced by the gain of temporal representativeness. We confirmed that POCIS samples only the dissolved fraction of dimethanamid and showed that for compounds like atrazine, desethylatrazine and metolachor, the POCIS concentration is equivalent to the whole water concentration. For dimethanamid, which exhibited a tendency to adsorb on suspended matter, we suggested a method to assess the raw water concentration from the POCIS measure