Geochemical behavior of rare earth elements in waters from the Pineta S. Vitale (Ravenna, Italy)

The Pineta S. Vitale is located in a lagoon system near the Adriatic Sea (Italy). This area is affected by subsidence, groundwater salinization and industrial contamination. A multidisciplinary research project was performed to evaluate the aqueous rare earth elements (REE), and to characterize the processes controlling their migration. Concentrations of total and dissolved elements were determined in 40 water samples (surface waters, soil waters, groundwater). Dissolved major and minor components generally show increasing concentrations from west to east towards the Adriatic Sea, and appear mostly derived from a marine source. Concentrations of REE vary from < 0.1 to 190 mu g/L, the highest values occur in soil waters. Correlations between Sigma REE and Al-Fe concentrations in the < 0.4 mu m filtered fraction have been observed. Shale-normalized patterns of RE in the soil waters show an enrichment in the - middle REE (MREE), likely due to preferential adsorption of the MREE onto < 0.4 mu m particles.