Title: Source relationships between streambank soils and streambed sediments in a mercury-contaminated stream

Abstract

Purpose: In contaminated streams, understanding the role of streambank and streambed source contributions is essential to developing robust remedial solutions. However, identifying relationships can be difficult because of the lack of identifying signatures in source and receptor pools. East Fork Poplar Creek (EFPC) in Oak Ridge, TN, USA received historical industrial releases of mercury that contaminated streambank soils and sediments. Here, we determined relationships between the contaminated streambank soils and sand-sized streambed sediments.Materials and methods: Field surveys revealed the spatial trends of the concentrations of inorganic total mercury (Hg) and methyl mercury (MeHg), Hg lability as inferred by sequential extraction, particle size distribution, and total organic carbon. Statistical tests were applied to determine relationships between streambank soil and streambed sediment properties.Results and discussion: Concentrations of Hg in streambank soils in the upper reaches averaged 206 mg kg^-1 (all as dry weight) (n = 457), and 13 mg kg^-1 in lower reaches (n = 321), while sand-sized streambed sediments were approximately 16 mg kg^-1 (n = 57). Two areas of much higher Hg and MeHg concentrations in streambank soils were identified and related to localized higher Hg concentrations in the streambed sediments; however, most of the streambank soils have similar Hgmore » concentrations to the streambed sediments. The molar ratio of Hg to organic carbon, correlation between MeHg and Hg, and particle size distributions suggested similarity between the streambank soils and the fine sand-sized fraction (125–250 μm) collected from the streambed sediments. Mercury in the fine sand-sized streambed sediments, however, was more labile than Hg in the streambank soils, suggesting an in-stream environment that altered the geochemistry of sediment-bound Hg.Conclusions: This study revealed major source areas of Hg in streambank soils, identified possible depositional locations in streambed sediments, and highlighted potential differences in the stability of Hg bound to streambank soils and sediments. This work will guide future remedial decision making in EFPC and will aid other researchers in identifying source–sink linkages in contaminated fluvial systems.« less

Authors:

Dickson, Johnbull O.; Mayes, Melanie A. ;

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• Search DOE PAGES for ORCID "0000-0001-6368-9210"

Brooks, Scott C.; Mehlhorn, Tonia L.; Lowe, Kenneth A.; Earles, Jennifer K.; Goñez-Rodriguez, Leroy; Watson, David B.; Peterson, Mark J.

Publication Date:

Fri Nov 09 00:00:00 EST 2018

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Environmental Management (EM)

OSTI Identifier:

1619375

Alternate Identifier(s):

OSTI ID: 1510576

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Published Article

Journal Name:

Journal of Soils and Sediments

Additional Journal Information:

Journal Name: Journal of Soils and Sediments Journal Volume: 19 Journal Issue: 4; Journal ID: ISSN 1439-0108

Publisher:

Springer Science + Business Media

Country of Publication:

Germany

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; Erosion; Fluvial; Methylmercury; Source–sink