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Copper transformation, speciation, and detoxification in anoxic and suboxic freshwater sediments

Cervi, E. C. and Clark, S. and Boye, K. E. and Gustafsson, Jon Petter and Baken, S. and Burton, G. A. (2021). Copper transformation, speciation, and detoxification in anoxic and suboxic freshwater sediments. Chemosphere. 282 , 131063
[Research article]

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Abstract

The complex chemistry of copper (Cu) in freshwater sediments at low concentrations is not well understood. We evaluated the transformation processes of Cu added to freshwater sediments under suboxic and anoxic conditions. Freshwater sediments from three sources in Michigan with different characteristics (Spring Creek, River Raisin, and Maple Lake) were spiked with 30 or 60 mg kg-1 Cu and incubated under a nitrogen atmosphere. After 28-d, each treatment subset was amended with organic matter (OM) to promote anoxic conditions and evaluate its effects on Cu speciation. OM addition triggered a shift from suboxic to anoxic conditions, and sequential extractions showed that Cu accordingly shifted from acid-soluble to oxidizable fractions. Extended X-ray absorption fine-structure (EXAFS) spectroscopy revealed that Cu sulfides dominated all anoxic samples except for Spring Creek 30 mg kgxfffd; 1, where Cu(I) was predominantly complexed to thiol groups of OM. Covellite and chalcopyrite (CuFeS2) were the predominant Cu species in nearly all anoxic samples, as determined by Raman spectroscopy, scanning electron microscopy, and X-ray absorption near-edge structure (XANES) spectroscopy. Copper reduction also occurred under suboxic conditions: for two of three sediments, around 80% had been reduced to Cu(I), while the remaining 20% persisted as Cu(II) complexed to OM. However, in the third coarsest (i.e., Spring Creek), around 50% of the Cu had been reduced, forming Cu(I)-OM complexes, while the remainder was Cu(II)-OM complexes. Toxicity tests showed that survival of H. azteca and D. magna were significantly lower in suboxic treatments. Anoxic sediments triggered a near-complete transformation of Cu to sulfide minerals, reducing its toxicity.

Authors/Creators:Cervi, E. C. and Clark, S. and Boye, K. E. and Gustafsson, Jon Petter and Baken, S. and Burton, G. A.
Title:Copper transformation, speciation, and detoxification in anoxic and suboxic freshwater sediments
Series Name/Journal:Chemosphere
Year of publishing :2021
Volume:282
Article number:131063
Number of Pages:14
Publisher:PERGAMON-ELSEVIER SCIENCE LTD
ISSN:0045-6535
Language:English
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution-Noncommercial-No Derivative Works 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:Geochemical speciation, Copper, EXAFS, XANES, Raman spectroscopy, Hyalella azteca, Daphnia magna, Aquatic toxicity
URN:NBN:urn:nbn:se:slu:epsilon-p-113267
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-113267
Additional ID:
Type of IDID
DOI10.1016/j.chemosphere.2021.131063
Web of Science (WoS)000679230700001
ID Code:25142
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: SLUpub Connector
Deposited On:01 Sep 2021 10:26
Metadata Last Modified:01 Sep 2021 10:31

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