title: Changes in catchment conditions lead to enhanced remobilization of arsenic in a water reservoir.
abstract: Increasing arsenic concentrations in freshwater ecosystems is of global concern. Processes affecting arsenic fluxes in catchments are known. These processes are in turn controlled by the underlying geology and air pollution history. In contrast to the knowledge on catchment processes less is known about the hydrochemical processes controlling the fixation/remobilization of arsenic within lakes and artificial reservoirs. Consequently, we examined a reservoir system in the Ore Mts. (Germany) regarding its sink and source potentials affecting arsenic fluxes. This area was faced with heavy deposition inputs from coal burning based acid rain until the beginning of the 1990s. Hereafter concentrations of sulfate and nitrate in runoff waters decreased, whereas dissolved organic carbon (DOC) concentrations are still increasing. Along with this, arsenic concentrations in the water discharge from the catchments increase. Our results reveal that the sediments of the investigated reservoir system contain high inventories of arsenic in association with ferric and organic phases. A nitrate deficit dependent arsenic release is suggested. It is indicated that arsenic release from the reservoir sediments may be controlled by water nitrate concentration, which in turn is dependent on the nitrate concentration in the runoff water from the catchment.
authors: Institute of General Ecology and Environmental Protection, Technische Universität Dresden, P.O. Box 1117, 01737 Tharandt, Germany. weiske@forst.tu-dresden.de
authors: Arndt
authors: A
authors: Weiske
authors: Jörg
authors: J
authors: Schaller
authors: Tilo
authors: T
authors: Hegewald
authors: Ulrike
authors: U
authors: Kranz
authors: Karl-Heinz
authors: KH
authors: Feger
authors: Ingo
authors: I
authors: Werner
authors: E Gert
authors: EG
authors: Dudel
mesh_terms: D001151:Arsenic / Q000032:analysis*; D002244:Carbon / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D019015:Geologic Sediments / Q000737:chemistry; D005858:Germany; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D002244:Carbon; D001151:Arsenic