Sediment sampling and sediment characterization
In each sampling location, composite samples of sediment were collected during summer 2013 by using a Van Veen grab (0–20 cm). Sediment samples were stored at 4 °C before and after their processing prior to characterization and metal determination analyses.
Sediment moisture was measured following UNE 77311 procedure (UNE, 2000). Porosity was measured according to DiToro (2001).Tex- ture, organic carbon and ammonium were determined according to El Rayis (1985) and Grashoff et al. (2002) respectively. The pH was deter- mined in pore water.