Editorial : Is it possible to extrapolate results of aquatic microcosm and mesocosm experiments with pesticides between climate zones in Europe?

1 IntroductionHigher tier studies to assess the environmental risks ofpesticides have been performed mainly in Atlantic CentralEurope and North America and results of such studies havebeen extrapolated to other climatic regions such as SouthEurope (Ramos et al. 2000; Lopez-Mancisidor et al. 2008a).Since climate (e.g., sun hours, rainfall, temperature), agro-ecosystems (e.g., crop rotation, field size), and edge-of-fieldsurface waters (e.g., hydrology, ecology) in those regions arequite different, it may be expected that exposure profiles andeffects of pesticides in surface waters are also different(Tarazona 2005; Lopez-Mancisidor et al. 2008a). It may thusbe questionable whether the extrapolation of results fromhigher tier studies over these regions is justified (Ramos etal. 2000; Lopez-Mancisidor et al. 2008a). On the other hand,it is neither financially nor practically feasible to test a largenumber of chemicals on a large number of species andcommunities in different localities (Brock et al. 2006). In theEU, these concerns were acknowledged with the recentadoption of a new regulation concerning the placing of plantprotection products on the market (Regulation (EC) No.1107/2009; EU 2009). According to this regulation, author-izations granted by one Member State should in principle beaccepted by other Member States where agricultural, planthealth, and environmental (including climatic) conditions arecomparable. To this end, three zones with such comparableecological and climatic conditions were distinguished,namely North, Central, and South (Table 1).Van Wijngaarden et al. (2005a), Van den Brink et al.(2006), and Maltby et al. (2009) reviewed aquatic modelecosystem studies carried out with insecticides, herbicides,and fungicides, respectively. The vast majority of theEuropean studies were conducted in the Central zone,whereas very few studies were reported for both the Southand the North zone (Table 1). To account for the lack ofstudies in the South zone, a research project was initiated in2010 that started with the set up of an outdoor microcosmfacility in Lisbon (Portugal). One of the aims of this facilityis to study the possibilities and limitations in the spatialextrapolation of regulatory acceptable concentrations(RACs) derived from outdoor micro-/mesocosm experi-ments between European climate zones. The present paperaims at summarizing differences in (1) ecology of edge-of-field surface waters, (2) exposure conditions to pesticides,(3) direct and indirect effects, and (4) recovery potential inpesticide stressed (semi-)field freshwater ecosystems underSouth zone compared to Central zone conditions that apriori may be anticipated. Implications for choices relatedto the experimental design of experiments in Portugal arediscussed based on this analysis.