Pollution in Mediterranean river ecosystems of the Iberian Peninsula: effects on benthic communities Mélange de contaminants dans les écosystèmes lotiques méditerranéens dans la Péninsule Ibérique : effets sur les communautés benthiques (biofilms).

We examined the presence of pharmaceutical products and metals, and their effects on biofilm communities in four Mediterranean large river basins (Llobregat, Ebro, Jucar and Guadalquivir) in the Iberian Peninsula. Five sites were selected in each river. In all the sites we analysed the occurrence of 81 pharmaceutical compounds (in water and sediment) as well as heavy metals (in water and biofilm communities). Several metrics were measured related to both the algal and bacterial components of fluvial biofilms. Heavy metal content (Mn, Fe, Co, Ni, Cu, Zn, As and Pb) in water and biofilm (bioaccumulated) showed an upstream-downstream gradient in all the river systems. The Guadalquivir and Llobregat had the highest concentrations of heavy metals, followed by Ebro and Jucar. The highest concentrations of pharmaceuticals in water were detected in the Llobregat, followed by Ebro, Jucar and Guadalquivir. The pharmaceutical with the highest concentrations were the x-ray contrast media, the compounds to treat hypertension and analgesics and anti-inflammatory products Multivariate analyses using the biological and pollutant variables revealed a potential relationship between metals (As and bioaccumulation of Cu) and the biofilm metrics. Certain effects of the pharmaceutical compounds in both structural and functional aspects of the biofilm community could be inferred from these relationships.