Metal(loid) speciation and size fractionation in sediment pore water depth profiles examined with a new meso profiling system. (July 2017)

• Record Type: Journal Article
• Authors: Schroeder, Henning; Fabricius, Anne-Lena; Ecker, Dennis; Ternes, Thomas A.; Duester, Lars
• Is Part Of: Chemosphere. Volume 179(2017)
• Page Start: 185
• Page End: 193
• Publication Date: 2017-07
• Subjects: Sediment pore water -- Depth profile -- Sediment water interface -- Profiling -- Metals; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.03.080
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In an exemplary incubation study with an anaerobic sediment sampled at an oxbow of the river Lahn in Germany (50°18′56.87″N; 7°37′41.25″E) and contaminated by former mining activity, a novel meso profiling and sampling system ( messy ) is presented. Messy enables a low invasive, automated sampling of pore water profiles across the sediment water interface (SWI), down to ∼20 cm depth with a spacial resolution of 1 cm. In parallel to the pore water sampling it measures physicochemical sediment parameters such as redox potential and pH value. In an incubation experiment of 151 days the ability of the setup was proven to address several different aspects relevant for fresh water and marine sediment studies: (i) The influence of mechanical disturbance and oxygen induced acidification on the mobility of 13 metals and metalloids (Cd, Co, Cu, Fe, Mn, Mo, Ni, Sb, U, V, Zn) was quantified based on 11 profiles. The analytes were quantified by inductively coupled plasma-mass spectrometry. Three groups of elements were identified with respect to the release into the pore water and the overlying water under different experimental conditions. (ii) The capability to investigate the impacts of changing physicochemical sediment properties on arsenic and antimony (III/V) speciation is shown. (iii) An approach to obtain information on size fractionation effects and to address the colloidal pore water fractions (0.45 μm–16 μm) was successfully conducted for the elements Ag, As, Cu, Fe and Mn. Highlights: A novel laboratory meso profiling and sampling system ( messy ) is introduced. Messy enables to survey the redox potential when sampling water across the sediment water interface (SWI) down to 20 cm depth. Messys performances in impact orientated release-, speciation, and size fractionation studies are demonstrated in a 151 days sediment incubation experiment. 13 metal(loid)s, As and Sb speciation and the colloidal fraction were addressed. 13 metal(loid)s) released into the pore water of an anaerobic oxbow sediment are grouped into those stronger impacted by mechanical disturbance and those impacted by natural acidification (oxygen induced pyrite weathering). A spike of Sb2 O3 did not impact Sb(III) concentration in the pore water during mechanical disturbance and acidification.