title: Mercury isotope signatures in contaminated sediments as a tracer for local industrial pollution sources.
abstract: Mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) may cause characteristic isotope signatures of different mercury (Hg) sources and help understand transformation processes at contaminated sites. Here, we present Hg isotope data of sediments collected near industrial pollution sources in Sweden contaminated with elemental liquid Hg (mainly chlor-alkali industry) or phenyl-Hg (paper industry). The sediments exhibited a wide range of total Hg concentrations from 0.86 to 99 μg g(-1), consisting dominantly of organically-bound Hg and smaller amounts of sulfide-bound Hg. The three phenyl-Hg sites showed very similar Hg isotope signatures (MDF δ(202)Hg: -0.2‰ to -0.5‰; MIF Δ(199)Hg: -0.05‰ to -0.10‰). In contrast, the four sites contaminated with elemental Hg displayed much greater variations (δ(202)Hg: -2.1‰ to 0.6‰; Δ(199)Hg: -0.19‰ to 0.03‰) but with distinct ranges for the different sites. Sequential extractions revealed that sulfide-bound Hg was in some samples up to 1‰ heavier in δ(202)Hg than organically-bound Hg. The selectivity of the sequential extraction was tested on standard materials prepared with enriched Hg isotopes, which also allowed assessing isotope exchange between different Hg pools. Our results demonstrate that different industrial pollution sources can be distinguished on the basis of Hg isotope signatures, which may additionally record fractionation processes between different Hg pools in the sediments.
authors.affiliation: Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich , CH-8092 Zurich, Switzerland.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Wiederhold
authors.forename: Ulf
authors.initials: U
authors.lastname: Skyllberg
authors.forename: Andreas
authors.initials: A
authors.lastname: Drott
authors.forename: Martin
authors.initials: M
authors.lastname: Jiskra
authors.forename: Sofi
authors.initials: S
authors.lastname: Jonsson
authors.forename: Erik
authors.initials: E
authors.lastname: Björn
authors.forename: Bernard
authors.initials: B
authors.lastname: Bourdon
authors.forename: Ruben
authors.initials: R
authors.lastname: Kretzschmar
mesh_terms: D005591:Chemical Fractionation; D004777:Environment; D004784:Environmental Monitoring; D004787:Environmental Pollution; D019015:Geologic Sediments / Q000032:analysis; D007221:Industry; D007554:Isotopes; D008628:Mercury / Q000032:analysis*; D017669:Mercury Compounds / Q000302:isolation & purification*; D008629:Mercury Isotopes / Q000032:analysis; D013548:Sweden
chemical_list: D007554:Isotopes; D017669:Mercury Compounds; D008629:Mercury Isotopes; D008628:Mercury