title: Cadmium speciation and accumulation in periphyton in a small stream with dynamic concentration variations.
abstract: Accumulation of cadmium in periphyton was investigated under field conditions while Cd concentration and speciation were dynamically varying in a small stream during rain events. Speciation in water was determined in situ by diffusion gradient in thin-films (DGT) and by modeling of complexation with fulvic acids. During the rain events, dissolved Cd concentrations increased from 0.17 nM to 0.27-0.36 nM, and 70-97% were DGT-labile. Cd content in periphyton closely followed Cd concentrations in water, despite higher concentrations of Zn and Mn, and may be controlled by either free or DGT-labile Cd concentrations. Decrease of Cd content in periphyton after the rain events was slower than the decrease of Cd concentration in water. Concentrations of Zn, Mn, Cu, Pb and Fe in periphyton also followed the dynamic variations of metal concentrations in water. Repeated exposure of periphyton to elevated dissolved Cd may lead to Cd accumulation.
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, P.O. Box 611, CH-8600 Duebendorf, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bradac
authors.forename: Bettina
authors.initials: B
authors.lastname: Wagner
authors.forename: David
authors.initials: D
authors.lastname: Kistler
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Traber
authors.forename: Renata
authors.initials: R
authors.lastname: Behra
authors.forename: Laura
authors.initials: L
authors.lastname: Sigg
mesh_terms: D018533:Biomass; D002104:Cadmium / Q000032:analysis*; D000458:Cyanobacteria / Q000737:chemistry; D017753:Ecosystem; D056890:Eukaryota / Q000737:chemistry*; D008670:Metals / Q000032:analysis; D008954:Models, Biological; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical; D002104:Cadmium