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(W/MF163) Evaluation of farming and agricultural impact in a freshwater ecosystem using biomarkers in cyprinids. Casini, S.1, Bucalossi, D.1, Leonzio, C.1, Fossi, M.C.2, Gavilan, J.F.3, 1 2 3 ABSTRACT- This study was planned to validate a monitoring tool for fresh water ecosystems based on biomarkers in cyprinids. Chub (Leuciscus cephalus cabeda) and barbel (Barbus barbus plebejus) were chosen as bioindicator species to monitor the potential impact of agricultural and farming activities on the river Merse in the south of Tuscany (Italy). Six sampling sites were selected along the river from the upper course (control) to the lower. A further control was selected in an unpolluted effluent of Merse, the stream Farma. Sites were located upstream and downstream from a big farm, an intense agricultural (cereals) area and a rice field with the aim of indentifying the single contribution of each activity to the effect on the ecosystem. All specimens were analysed for epatic MFO activities (EROD, BPMO), brain acethylcolinesterases activities (AChE), PAH bile metabolites, plasmatic vitellogenin and zona radiata proteins and Somatic Liver Index (SLI). Biomarkers showed to have a sensitive response on these cyprinids: MFO activities were strongly induced in specimens collected downstream from the farm, and increased downstream from the cereals and rice fields. AChE was significantly inhibited in the site located at the lower part of the river. PAH bile metabolites were not significantly present in the chub, while preliminary data on barbel indicates high levels of these compounds. Vitellogenin and zona radiata proteins in chub did not show induction in specimens of the different sites with respect to controls. Somatic Liver Index was higher in the sites of MFO induction. This study validated the potential use of the two species of cyprinids as bioindicators because of their highly sensitive response to contaminants. They are ubiquitous in most fresh water courses, easily obtainable and do not migrate, thus, they can be proposed for large scale monitoring of effects caused by pollution. Key words: Cyprinids, biomarkers, freshwater ecosystem |
