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Sources of riverine mercury across the Mackenzie River Basin; inferences from a combined Hg\\C isotopes and optical properties approach

Campeau, Audrey and Eklöf, Karin and Soerensen, Anne L. and Akerblom, Staffan and Yuan, Shengliu and Hintelmann, Holger and Bieroza, Magdalena and Köhler, Stephan and Zdanowicz, Christian (2022). Sources of riverine mercury across the Mackenzie River Basin; inferences from a combined Hg\\C isotopes and optical properties approach. Science of the Total Environment. 806 , 150808
[Research article]

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Abstract

The Arctic environment harbors a complex mosaic of mercury (Hg) and carbon (C) reservoirs, some of which are rapidly destabilizing in response to climate warming. The sources of riverine Hg across the Mackenzie River basin (MRB) are uncertain, which leads to a poor understanding of potential future release. Measurements of dissolved and particulate mercury (DHg, PHg) and carbon (DOC, POC) concentration were performed, along with analyses of Hg stable isotope ratios (incl. Delta 199Hg, delta 202Hg), radiocarbon content (Delta 14C) and optical properties of DOC of river water. Isotopic ratios of Hg revealed a closer association to terrestrial Hg reservoirs for the particulate fraction, while the dissolved fraction was more closely associated with atmospheric deposition sources of shorter turnover time. There was a positive correlation between the Delta 14C-OC and riverine Hg concentration for both particulate and dissolved fractions, indicating that waters transporting older-OC (14C-depleted) also contained higher levels of Hg. In the dissolved fraction, older DOC was also associated with higher molecular weight, aromaticity and humic content, which are likely associated with higher Hg-binding potential. Riverine PHg concentration increased with turbidity and SO4 concentration. There were large contrasts in Hg concentration and OC age and quality among the mountain and lowland sectors of the MRB, which likely reflect the spatial distribution of various terrestrial Hg and OC reservoirs, including weathering of sulfate minerals, erosion and extraction of coal deposits, thawing permafrost, forest fires, peatlands, and forests. Results revealed major differences in the sources of particulate and dissolved riverine Hg, but nonetheless a common positive association with older

Authors/Creators:Campeau, Audrey and Eklöf, Karin and Soerensen, Anne L. and Akerblom, Staffan and Yuan, Shengliu and Hintelmann, Holger and Bieroza, Magdalena and Köhler, Stephan and Zdanowicz, Christian
Title:Sources of riverine mercury across the Mackenzie River Basin; inferences from a combined Hg\\C isotopes and optical properties approach
Series Name/Journal:Science of the Total Environment
Year of publishing :2022
Volume:806
Article number:150808
Number of Pages:12
Publisher:ELSEVIER
ISSN:0048-9697
Language:English
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Environmental Sciences (social aspects to be 507)
Keywords:Mercury, Organic carbon, Stable, Radiocarbon, Fluorescence, Mackenzie River
URN:NBN:urn:nbn:se:slu:epsilon-p-116016
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-116016
Additional ID:
Type of IDID
DOI10.1016/j.scitotenv.2021.150808
Web of Science (WoS)000744101000003
ID Code:27167
Faculty:S - Faculty of Forest Sciences
NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(S) > Dept. of Forest Ecology and Management
(NL, NJ) > Dept. of Aquatic Sciences and Assessment
(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: SLUpub Connector
Deposited On:21 Feb 2022 15:13
Metadata Last Modified:21 Feb 2022 15:21

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