title: Identification of multiple mercury sources to stream sediments near Oak Ridge, TN, USA.
abstract: Sediments were analyzed for total Hg concentration (THg) and isotopic composition from streams and rivers in the vicinity of the Y-12 National Security Complex (Y12) in Oak Ridge, TN (USA). In the stream directly draining Y12, where industrial releases of mercury (Hg) have been documented, high THg (3.26 to 60.1 μg/g) sediments had a distinct Hg isotopic composition (δ(202)Hg of 0.02 ± 0.15‰ and Δ(199)Hg of -0.07 ± 0.03‰; mean ± 1SD, n = 12) compared to sediments from relatively uncontaminated streams in the region (δ(202)Hg = -1.40 ± 0.06‰ and Δ(199)Hg of -0.26 ± 0.03‰; mean ± 1SD, n = 6). Additionally, several streams that are nearby but do not drain Y12 had sediments with intermediate THg (0.06 to 0.21 μg/g) and anomalous δ(202)Hg (as low as -5.07‰). We suggest that the low δ(202)Hg values in these sediments provide evidence for the contribution of an additional Hg source to sediments, possibly derived from atmospheric deposition. In sediments directly downstream of Y12 this third Hg source is not discernible, and the Hg isotopic composition can be largely explained by the mixing of low THg sediments with high THg sediments contaminated by Y12 discharges.
authors.affiliation: University of Michigan , Department of Earth and Environmental Sciences, 1100 North University Avenue, Ann Arbor, Michigan 48109, United States.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Donovan
authors.forename: Joel D
authors.initials: JD
authors.lastname: Blum
authors.forename: Jason D
authors.initials: JD
authors.lastname: Demers
authors.forename: Baohua
authors.initials: B
authors.lastname: Gu
authors.forename: Scott C
authors.initials: SC
authors.lastname: Brooks
authors.forename: John
authors.initials: J
authors.lastname: Peryam
mesh_terms: D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D008629:Mercury Isotopes; D045483:Rivers / Q000737:chemistry*; D013714:Tennessee; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008629:Mercury Isotopes; D014874:Water Pollutants, Chemical; D008628:Mercury