eCite Digital Repository

Influence of late-Holocene climate change on the solid-phase speciation and long-term stability of arsenic in sub-Arctic lake sediments

Citation

Miller, CB and Parsons, MB and Jamieson, HE and Ardakani, OH and Gregory, BRB and Galloway, JM, Influence of late-Holocene climate change on the solid-phase speciation and long-term stability of arsenic in sub-Arctic lake sediments, Science of The Total Environment, 709 Article 136115. ISSN 0048-9697 (2020) [Refereed Article]

Copyright Statement

Crown Copyright 2019 Published by Elsevier B.V. All rights reserved.

DOI: doi:10.1016/j.scitotenv.2019.136115

Abstract

Sediment cores were collected from two lakes in the Courageous Lake Greenstone Belt (CLGB), central Northwest Territories, Canada, to examine the influence of late-Holocene warming on the transport and fate of arsenic (As) in sub-Arctic lakes. In both lakes, allochthonous As-bearing minerals (i.e. arsenopyrite and scorodite) were identified in sediment deposited during times of both regional warming and cooling, suggesting that weathering of bedrock and derived surficial materials provides a continual source of As to lakes of the CLGB. However, maximum porewater As (84μgL−1 and 15μgL−1) and reactive organic matter (OM; aquatic and terrestrial-derived) concentrations in each lake are coincident with known periods of regional climate warming. It is inferred that increased biological production in surface waters and influx of terrigenous OM led to the release of sedimentary As to porewater through reductive dissolution of As-bearing Fe-(oxy)hydroxides and scorodite during episodes of regional warming. Elevated sedimentary As concentrations (median: 36mgkg−1; range: 29 to 49mgkg−1) are observed in sediment coeval with the Holocene Thermal Maximum (ca. 5430110 to 4070130cal.yearsBP); at these depths, authigenic As-bearing framboidal pyrite is the primary host of As in sediment and the influence of organic matter on the precipitation of As-bearing framboidal pyrite is apparent petrographically. These findings suggest that increased biological productivity and weathering of terrestrial OM associated with climate warming influences redox cycles in the near-surface sediment and enhances the mobility of As in northern lakes. Knowledge generated from this study is relevant for predicting future climate change-driven variations in metal(loid) cycling in aquatic systems and can be used to interpret trends in long-term environmental monitoring data at historical, modern, and future metal mines in northern environments.

Item Details

Item Type:Refereed Article
Keywords:arsenic mobility, climate change, mine waste, lake sediments, organic matter, geochemical baselines
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Organic geochemistry
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Rehabilitation or conservation of terrestrial environments
UTAS Author:Miller, CB (Dr Clare Miller)
ID Code:138608
Year Published:2020 (online first 2019)
Web of Science® Times Cited:2
Deposited By:Earth Sciences
Deposited On:2020-04-17
Last Modified:2020-07-27
Downloads:0

Repository Staff Only: item control page