Tracing lake pollution, eutrophication and partial recovery from the sediments of Windermere, UK, using geochemistry and sediment microfabrics
Tracing lake pollution, eutrophication and partial recovery from the sediments of Windermere, UK, using geochemistry and sediment microfabrics
Many lakes undergo anthropogenically driven eutrophication and pollution leading to decreased water and sediment quality. These effects can enhance seasonally changing lake redox conditions that may concentrate potentially toxic elements. Here we report the results of a multi-method geochemical and sediment microfabric analysis applied to reconstruct the history of cultural eutrophication and pollution of the North and South Basins of Windermere, UK. Eutrophication developed from the mid-19th to the earliest 20th centuries. Enhanced lake productivity is indicated by increased sedimentary δ13C, and increased pollution by a higher concentration of metals (Pb, Hg, and As) in the sediment, likely enhanced by incorporation and adsorption to settling diatom aggregates, preserved as sedimentary laminae. In the South Basin, increasing sediment δ15N values occur in step with Zn, Hg, and Cu, linking metal enrichment to isotopically heavy nitrate (N) from anthropogenic sources. From around 1930, decreases in Mn and Fe-rich laminae indicate reduced deep-water ventilation, whereas periods of sediment anoxia increased, being most severe in the deeper North Basin. Strongly reducing sediment conditions promoted Fe and Mn reduction and Pb-bearing barite formation, hitherto only described from toxic minewastes and contaminated soils. From1980 there was an increase in indicators of bottomwater oxygenation,
although not to before 1930. But in the South Basin, the continued impacts of sewage are indicated by elevated sediment δ15N. Imaging and X-ray microanalysis using scanning electron microscopy has shown seasonal-scale redoxmineralisation ofMn, Fe, and Ba related to intermittent sediment anoxia. Elevated concentrations of these metals and As also occur in the surficial sediment and provide evidence for dynamic redoxmobilisation of potentially toxic elements to the lake water. Concentrations of As (up to 80 ppm), exceed international Sediment Quality Standards. This process may become more prevalent in the future with climate change driving lengthened summer stratification.
Cultural eutrophication, Isotopic analysis, Itrax XRF core scanning, Paleolimnology, Scanning electron microscopy, multi-method
1-20
Fielding, J. James
262ffd14-1f1e-4211-bac8-45aac06f5c74
Croudace, Ian
24deb068-d096-485e-8a23-a32b7a68afaf
Kemp, Alan
131b479e-c2c4-47ae-abe1-ad968490960e
Pearce, Richard
7d772b25-3ad0-4909-9a96-3a1a8111bc2f
Cotterill, Carol
cc09513b-fd65-4fa3-a95e-90fafb1aa37c
Langdon, Peter
95b97671-f9fe-4884-aca6-9aa3cd1a6d7f
Avery, Rachael
e2310327-14c0-4c0b-a03f-31207cab95c2
20 June 2020
Fielding, J. James
262ffd14-1f1e-4211-bac8-45aac06f5c74
Croudace, Ian
24deb068-d096-485e-8a23-a32b7a68afaf
Kemp, Alan
131b479e-c2c4-47ae-abe1-ad968490960e
Pearce, Richard
7d772b25-3ad0-4909-9a96-3a1a8111bc2f
Cotterill, Carol
cc09513b-fd65-4fa3-a95e-90fafb1aa37c
Langdon, Peter
95b97671-f9fe-4884-aca6-9aa3cd1a6d7f
Avery, Rachael
e2310327-14c0-4c0b-a03f-31207cab95c2
Fielding, J. James, Croudace, Ian, Kemp, Alan, Pearce, Richard, Cotterill, Carol, Langdon, Peter and Avery, Rachael
(2020)
Tracing lake pollution, eutrophication and partial recovery from the sediments of Windermere, UK, using geochemistry and sediment microfabrics.
Science of the Total Environment, 722, , [137745].
(doi:10.1016/j.scitotenv.2020.137745).
Abstract
Many lakes undergo anthropogenically driven eutrophication and pollution leading to decreased water and sediment quality. These effects can enhance seasonally changing lake redox conditions that may concentrate potentially toxic elements. Here we report the results of a multi-method geochemical and sediment microfabric analysis applied to reconstruct the history of cultural eutrophication and pollution of the North and South Basins of Windermere, UK. Eutrophication developed from the mid-19th to the earliest 20th centuries. Enhanced lake productivity is indicated by increased sedimentary δ13C, and increased pollution by a higher concentration of metals (Pb, Hg, and As) in the sediment, likely enhanced by incorporation and adsorption to settling diatom aggregates, preserved as sedimentary laminae. In the South Basin, increasing sediment δ15N values occur in step with Zn, Hg, and Cu, linking metal enrichment to isotopically heavy nitrate (N) from anthropogenic sources. From around 1930, decreases in Mn and Fe-rich laminae indicate reduced deep-water ventilation, whereas periods of sediment anoxia increased, being most severe in the deeper North Basin. Strongly reducing sediment conditions promoted Fe and Mn reduction and Pb-bearing barite formation, hitherto only described from toxic minewastes and contaminated soils. From1980 there was an increase in indicators of bottomwater oxygenation,
although not to before 1930. But in the South Basin, the continued impacts of sewage are indicated by elevated sediment δ15N. Imaging and X-ray microanalysis using scanning electron microscopy has shown seasonal-scale redoxmineralisation ofMn, Fe, and Ba related to intermittent sediment anoxia. Elevated concentrations of these metals and As also occur in the surficial sediment and provide evidence for dynamic redoxmobilisation of potentially toxic elements to the lake water. Concentrations of As (up to 80 ppm), exceed international Sediment Quality Standards. This process may become more prevalent in the future with climate change driving lengthened summer stratification.
Text
Fielding_etal_2020_Accepted_Manuscript
- Accepted Manuscript
Text
1-s2.0-S0048969720312560-main
- Version of Record
Restricted to Repository staff only
Request a copy
Text
Tracing lake pollution, eutrophication and partial recovery from the sediments ofWindermere, UK, using geochemistry and sediment microfabrics
Restricted to Repository staff only
Request a copy
Text
Fielding_etal_2020_Accepted_Manuscript2
More information
Accepted/In Press date: 3 March 2020
e-pub ahead of print date: 9 March 2020
Published date: 20 June 2020
Additional Information:
Funding Information:
In addition to those mentioned in the funding acknowledgments the authors would like to express their gratitude to the Rock Preparation and Thin-Sectioning Laboratory and the Stable Isotope Mass-spectrometry at the National Oceanography Centre, UK. We would also like to thank Kate Davis for her assistance with drafting some figures. Finally, we would like to thank the reviewers whose helpful comments improved this manuscript greatly. This work was supported by the NERC Radiocarbon Facility NRCF010001 (allocation numbers 1856.1014 and 1736.1013). This research was supported by a University of Southampton Studentship Grant and a Natural Environmental Research Council Studentship Grant (NE/L50161X/1).
Publisher Copyright:
© 2018
Keywords:
Cultural eutrophication, Isotopic analysis, Itrax XRF core scanning, Paleolimnology, Scanning electron microscopy, multi-method
Identifiers
Local EPrints ID: 438999
URI: http://eprints.soton.ac.uk/id/eprint/438999
ISSN: 0048-9697
PURE UUID: 7f7604a3-8d49-4b57-9be6-d717f2210eec
Catalogue record
Date deposited: 31 Mar 2020 16:31
Last modified: 17 Mar 2024 05:27
Export record
Altmetrics
Contributors
Author:
J. James Fielding
Author:
Carol Cotterill
Author:
Rachael Avery
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics