Application of ecological risk indicators for the assessment of greek surficial sediments contaminated by toxic metalsApplication of ecological risk indicators for the assessment of greek surficial sediments contaminated by toxic metals Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2018-10-152016enΤhe present research investigates the partitioning of six selected toxic metals (Ni, Cr, Pb, Zn, Cu, and As) in eight sediment samples; half of them were collected from Elefsis Gulf, and the other half were taken from Koumoundourou Lake, Athens, Greece. Each one of them was treated by applying Tessier’s five-step sequential extraction procedure. Regarding gulf sediments, the results indicated that Cu exhibits a strong affinity to the organic matter with percentages ranging from 65 to 78 %. Considerable amount of Zn (32–40 %) is bound to the Fe-Mn fraction and the non-residual fraction, while Cr and Ni are bound to the organic fraction, an observation that suits all toxic metals examined. Regarding lake sediments, Pb is the predominant metal bound to Fe-Mn (48–51 %). It is also noteworthy that the percentage of Zn bound to carbonated fraction (5–15 %), indicating biological availability. In conclusion, the application of several ecological risk indicators demonstrated that Elefsis Gulf sediments correspond to a moderate pollution level, with Pb and Ni being less bioavailable than in the lake’s samples, in contrast to Zn which is more bioavailable. Finally, Koumoundourou Lakes’ basin is characterized of “low risk.”http://creativecommons.org/licenses/by/4.0/Environmental Monitoring and Assessment1885 Chachladakis Ioannis Χαχλαδακης Ιωαννης Vasilaki Georgia Βασιλακη Γεωργια Smaragdaki Eleftheria Σμαραγδακη Ελευθερια Gidarakos Evaggelos Γιδαρακος Ευαγγελος Springer Nature [academic journals on nature.com] Partitioning Risk assessment Sediments Sequential extraction Toxic metals