Aquatic Toxicology 101 (2011) 228–236 Contents lists available at ScienceDirect Aquatic Toxicology journal homepage: www.elsevier.com/locate/aquatox Active bio-monitoring of contamination in aquatic systems—An in situ translocation experiment applying the PICT concept Stefanie Rotter a,∗ , Frédéric Sans-Piché a , Georg Streck b , Rolf Altenburger a , Mechthild Schmitt-Jansen a a Department Bioanalytical Ecotoxicology, Helmholtz-Centre for Environmental Research – UFZ, Permoserstr. 15, 04318 Leipzig, Germany b Department of Effect-Directed Analysis, Helmholtz-Centre for Environmental Research – UFZ, Permoserstr. 15, 04318 Leipzig, Germany article info Article history: Received 17 June 2010 Received in revised form 1 October 2010 Accepted 5 October 2010 Keywords: Diatoms Field transfer River periphyton PICT POCIS Prometryn abstract The environmental risk assessment of toxicants is often derived from chemical monitoring, based on single species tests performed in the laboratory. However, to provide ecologically relevant information, community approaches are required. The aim of this study was to causally link prometryn exposure to community-level effects in complex field situations and to identify response times of adaptation to pollution and recovery from pollution. For this reason sensitivity shifts in communities were detected and related to structural changes within the periphyton community. Furthermore, it was intended to illustrate the possibility of a combined approach of community translocation and sensitivity assessment for active monitoring of polluted sites. Periphyton was grown at a reference (R) and at a polluted (P) site of the river Elbe basin for 26 days, was subsequently transferred from the polluted site to the reference site and vice versa. Sensitivity of communities to prometryn was determined according to the pollution-induced community tolerance (PICT)-concept in short-term tests by measuring photosynthesis inhibition and was related to structural changes in algal class and diatom species composition. Exposure to prometryn was determined using polar organic integrative samplers (POCIS), giving time-weighted average concentrations. Environmental concentrations of prometryn were significantly higher at the polluted site compared to the reference site. Communities grown at the polluted site showed a higher tolerance to prometryn in comparison to the reference site. 17 Days after the translocation to the reference site, EC 50 decreased 2-fold compared to the non-translocated P-community of the same age. By contrast, EC 50 of the community grown at the reference site was 5 times higher after 17 days exposure at the polluted site. Furthermore, P–R commu- nities were less sensitive to prometryn (higher EC 50 ) than R–P communities, 24 days after translocation. These changes in sensitivity to prometryn were consistent with changes in species composition and clearly indicate that the exposure history of communities is defining the time-response of recovery and adaptation. In conclusion, the PICT-concept is shown to be a suitable tool for analysis of recovery and adapta- tion processes of communities under natural conditions. Therefore, it improves the link between cause and effect in field situations. In situ translocation studies provide an ecological relevant assessment of pesticide effects under field conditions and could be used as a diagnostic tool in active monitoring for decision-making frameworks as used in the implementation of the European Water Framework Directive (WFD). © 2010 Elsevier B.V. All rights reserved. ∗ Corresponding author at: Helmholtz-Centre for Environmental Research – UFZ, Permoserstr. 15, 04318 Leipzig, Germany. Tel.: +49 3412351527; fax: +49 341235451527. E-mail addresses: stefanie.rotter@ufz.de (S. Rotter), mechthild.schmitt@ufz.de (M. Schmitt-Jansen). 1. Introduction Chemical pollution of aquatic ecosystems is a major environ- mental problem (Schwarzenbach et al., 2006), which leads to changes in all trophic levels of the ecosystem (Geiszinger et al., 2009). The assessment of ecotoxicological effects is often based on chemical monitoring to evaluate environmental concentrations and subsequently linked to biological effects. This effect assessment is mainly based on simplified approaches performed at suborgan- ism or organism level under standardised laboratory conditions. 0166-445X/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.aquatox.2010.10.001