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(029) Interpretation of groundwater monitoring data. Linders, Jan1, Boesten, Jos2, Brouwer, Willem3, Leistra, Minze2, van der Linden, Ton1, Verschoor, Anja1, Pol, Werner4, 1 2 3 4 ABSTRACT- The presentation will deal with the current availability of monitoring data in the registration process of plant protection products. Local, regional and national bodies may have initiated monitoring of pesticides that have been used for a series of years. But for new pesticides inherently no monitoring data can be available. Before monitoring data can play an important role in the registration procedure, certain quality criteria should be met, especially, when focusing on groundwater, the relation between the measurements and the agricultural practice. If this relation is not ascertained it does not seem possible to use the results. The method of sampling and analysis are taken into account as quality criteria, as well as the recovery of the analysis and the reproducibility. The limit of determination and of quantification should be sufficiently low because of the low limit value of 0.1 Key words: monitoring, risk assessment, pesticides |
g/l. In reporting and interpretation of the results, information on e.g. the soils, slopes and crops together with relevant meteorological data is required. In the monitoring of deep groundwater the sources, flow paths and travel times should be known. Some discussion points are presented on the weight of evidence, the decision making percentile, average or median value to be used, etc.. It is argued that results orf well-defined monitoring programmes need to be taken into account in the registration of pesticides. If the relation between application and measurement is established, the results form very strong evidence of the possible contamination of groundwater with the pesticide under consideration. The position of post-registration monitoring will be discussed as well as a proposal to develop a tiered approach for the use of monitoring data in registration processes in the Netherlands.