Increasing temperature and flow management alter mercury dynamics in East Fork Poplar Creek

Scott C. Brooks; Carrie L. Miller; Ami L. Riscassi; Kenneth A. Lowe; Johnbull O. Dickson; Grace E. Schwartz

doi:10.1002/hyp.14344

Increasing temperature and flow management alter mercury dynamics in East Fork Poplar Creek

Scott C. Brooks, Carrie L. Miller, Ami L. Riscassi, Kenneth A. Lowe, Johnbull O. Dickson, Grace E. Schwartz

Biogeochemical Dynamics

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

East Fork Poplar Creek (EFPC) is a mercury (Hg) contaminated creek in east Tennessee, USA. Stream restoration activities included the initiation of a flow management programme in 1996 in which water from a nearby lake was pumped to the head of the creek. We conducted regular water sampling for 2 years along the length of EFPC during active flow management and for 5 years after flow management stopped. Total Hg and total monomethylmercury (MMHg) concentration and flux decreased in the uppermost reaches of EFPC that were closest to the point of water addition. Most water quality parameters, including DOC concentration, remained unchanged after flow management termination. Nevertheless, SUVA₂₅₄, a measure of dissolved organic matter (DOM) composition, increased and coincided with increased dissolved Hg (Hg_D) concentration and flux and decreased Hg solid-water partitioning coefficients throughout EFPC. Higher SUVA₂₅₄ and Hg_D concentration have potential implications for bioavailability and MMHg production. Total and dissolved MMHg concentrations increased in lower reaches of EFPC after the end of flow management and these increases were most pronounced during spring and early summer when biota are more susceptible to exposure and uptake. A general warming trend in the creek after active flow management ended likely acted in concert with higher Hg_D concentration to promote higher MMHg concentration. Total and dissolved MMHg concentrations were positively correlated with water temperature above a threshold value of 10°C. Concentration changes for Hg and MMHg could not be accounted for by changes in creek discharge that accompanied the cessation of flow management. In addition to the changing DOM composition in-stream, other watershed-scale factors likely contributed to the observed patterns, as these changes occurred over months rather than instantaneously after flow management stopped. Nevertheless, similar changes in MMHg have not been observed in a tributary to EFPC.

Original language	English
Article number	e14344
Journal	Hydrological Processes
Volume	35
Issue number	8
DOIs	https://doi.org/10.1002/hyp.14344
State	Published - Aug 2021

Funding

This work was funded by the US Department of Energy, Office of Science, Biological and Environmental Research, Subsurface Biogeochemical Research (SBR) Programme, the US Department of Energy's Oak Ridge Office of Environmental Management (OROEM), and URS | CH2M Oak Ridge LLC (UCOR). The isotopes used in this research were supplied by the United States Department of Energy Office of Science by the Isotope Programme in the Office of Nuclear Physics. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the US Department of Energy under contract DE-AC05-00OR22725. This work was funded by the US Department of Energy, Office of Science, Biological and Environmental Research, Subsurface Biogeochemical Research (SBR) Programme, the US Department of Energy's Oak Ridge Office of Environmental Management (OROEM), and URS | CH2M Oak Ridge LLC (UCOR). The isotopes used in this research were supplied by the United States Department of Energy Office of Science by the Isotope Programme in the Office of Nuclear Physics. Oak Ridge National Laboratory is managed by UT‐Battelle, LLC, for the US Department of Energy under contract DE‐AC05‐00OR22725.

Keywords

managed flow
mercury
methylmercury
stream chemistry
water quality

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10.1002/hyp.14344

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@article{596ec34419db4e9faf4b40fd2a83d15b,

title = "Increasing temperature and flow management alter mercury dynamics in East Fork Poplar Creek",

abstract = "East Fork Poplar Creek (EFPC) is a mercury (Hg) contaminated creek in east Tennessee, USA. Stream restoration activities included the initiation of a flow management programme in 1996 in which water from a nearby lake was pumped to the head of the creek. We conducted regular water sampling for 2 years along the length of EFPC during active flow management and for 5 years after flow management stopped. Total Hg and total monomethylmercury (MMHg) concentration and flux decreased in the uppermost reaches of EFPC that were closest to the point of water addition. Most water quality parameters, including DOC concentration, remained unchanged after flow management termination. Nevertheless, SUVA254, a measure of dissolved organic matter (DOM) composition, increased and coincided with increased dissolved Hg (HgD) concentration and flux and decreased Hg solid-water partitioning coefficients throughout EFPC. Higher SUVA254 and HgD concentration have potential implications for bioavailability and MMHg production. Total and dissolved MMHg concentrations increased in lower reaches of EFPC after the end of flow management and these increases were most pronounced during spring and early summer when biota are more susceptible to exposure and uptake. A general warming trend in the creek after active flow management ended likely acted in concert with higher HgD concentration to promote higher MMHg concentration. Total and dissolved MMHg concentrations were positively correlated with water temperature above a threshold value of 10°C. Concentration changes for Hg and MMHg could not be accounted for by changes in creek discharge that accompanied the cessation of flow management. In addition to the changing DOM composition in-stream, other watershed-scale factors likely contributed to the observed patterns, as these changes occurred over months rather than instantaneously after flow management stopped. Nevertheless, similar changes in MMHg have not been observed in a tributary to EFPC.",

keywords = "managed flow, mercury, methylmercury, stream chemistry, water quality",

author = "Brooks, {Scott C.} and Miller, {Carrie L.} and Riscassi, {Ami L.} and Lowe, {Kenneth A.} and Dickson, {Johnbull O.} and Schwartz, {Grace E.}",

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year = "2021",

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doi = "10.1002/hyp.14344",

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T1 - Increasing temperature and flow management alter mercury dynamics in East Fork Poplar Creek

AU - Brooks, Scott C.

AU - Miller, Carrie L.

AU - Riscassi, Ami L.

AU - Lowe, Kenneth A.

AU - Dickson, Johnbull O.

AU - Schwartz, Grace E.

PY - 2021/8

Y1 - 2021/8

N2 - East Fork Poplar Creek (EFPC) is a mercury (Hg) contaminated creek in east Tennessee, USA. Stream restoration activities included the initiation of a flow management programme in 1996 in which water from a nearby lake was pumped to the head of the creek. We conducted regular water sampling for 2 years along the length of EFPC during active flow management and for 5 years after flow management stopped. Total Hg and total monomethylmercury (MMHg) concentration and flux decreased in the uppermost reaches of EFPC that were closest to the point of water addition. Most water quality parameters, including DOC concentration, remained unchanged after flow management termination. Nevertheless, SUVA254, a measure of dissolved organic matter (DOM) composition, increased and coincided with increased dissolved Hg (HgD) concentration and flux and decreased Hg solid-water partitioning coefficients throughout EFPC. Higher SUVA254 and HgD concentration have potential implications for bioavailability and MMHg production. Total and dissolved MMHg concentrations increased in lower reaches of EFPC after the end of flow management and these increases were most pronounced during spring and early summer when biota are more susceptible to exposure and uptake. A general warming trend in the creek after active flow management ended likely acted in concert with higher HgD concentration to promote higher MMHg concentration. Total and dissolved MMHg concentrations were positively correlated with water temperature above a threshold value of 10°C. Concentration changes for Hg and MMHg could not be accounted for by changes in creek discharge that accompanied the cessation of flow management. In addition to the changing DOM composition in-stream, other watershed-scale factors likely contributed to the observed patterns, as these changes occurred over months rather than instantaneously after flow management stopped. Nevertheless, similar changes in MMHg have not been observed in a tributary to EFPC.

AB - East Fork Poplar Creek (EFPC) is a mercury (Hg) contaminated creek in east Tennessee, USA. Stream restoration activities included the initiation of a flow management programme in 1996 in which water from a nearby lake was pumped to the head of the creek. We conducted regular water sampling for 2 years along the length of EFPC during active flow management and for 5 years after flow management stopped. Total Hg and total monomethylmercury (MMHg) concentration and flux decreased in the uppermost reaches of EFPC that were closest to the point of water addition. Most water quality parameters, including DOC concentration, remained unchanged after flow management termination. Nevertheless, SUVA254, a measure of dissolved organic matter (DOM) composition, increased and coincided with increased dissolved Hg (HgD) concentration and flux and decreased Hg solid-water partitioning coefficients throughout EFPC. Higher SUVA254 and HgD concentration have potential implications for bioavailability and MMHg production. Total and dissolved MMHg concentrations increased in lower reaches of EFPC after the end of flow management and these increases were most pronounced during spring and early summer when biota are more susceptible to exposure and uptake. A general warming trend in the creek after active flow management ended likely acted in concert with higher HgD concentration to promote higher MMHg concentration. Total and dissolved MMHg concentrations were positively correlated with water temperature above a threshold value of 10°C. Concentration changes for Hg and MMHg could not be accounted for by changes in creek discharge that accompanied the cessation of flow management. In addition to the changing DOM composition in-stream, other watershed-scale factors likely contributed to the observed patterns, as these changes occurred over months rather than instantaneously after flow management stopped. Nevertheless, similar changes in MMHg have not been observed in a tributary to EFPC.

KW - managed flow

KW - mercury

KW - methylmercury

KW - stream chemistry

KW - water quality

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DO - 10.1002/hyp.14344

M3 - Article

AN - SCOPUS:85113509501

SN - 0885-6087

VL - 35

JO - Hydrological Processes

JF - Hydrological Processes

IS - 8

M1 - e14344

ER -

Increasing temperature and flow management alter mercury dynamics in East Fork Poplar Creek

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