Metal ratio mixing models clarify metal contamination sources to lake sediments in Yunnan, China

Daniel J. Bain, Aubrey L. Hillman, Mark B. Abbott, Rebecca A. Tisherman, Duo Wu

Research output: Contribution to journalArticlepeer-review

Abstract

Contaminated legacy sediments contribute to modern pollution loadings, particularly trace metals. These contributions are challenging to quantify as metal histories reconstructed from sediment records cannot be easily divided into legacy and concurrent contamination. In particular, the contribution from re-mobilization and delivery of legacy metals stored in catchment soil, colluvial, and fluvial environments are rarely considered or quantified when interpreting sediment records. Here, extended records of metals accumulation for a set of three lakes in Yunnan, China are compared with endmember chemistries using Monte Carlo-Markov Chain mixing models to help identify source contributions to the sediments. This approach allows attribution of metals transported by atmospheric and fluvial mechanisms in a region with a history of mining and metallurgy spanning millennia. These analyses reveal distinct source mixtures and demonstrate the sensitivity of lake records to basin sediment dynamics. In particular, substantial proportions of elevated metal concentrations in these lake systems seem to arise from soil contributions more than from atmospheric deposition of smelting emissions. The largest soil contributions seem to be in Erhai, a lake with erosion prone soils closely “connected” to the lake. Moreover, these invesigations illustrate the potential for mixing approaches to accommodate and clarify uncertainties in metal source and extraction as differences in extraction efficiency can be incorporated into source uncertainty estimates. Ultimately, these approaches emphasize the need to account for fluvial metal transport in interpretation of sediment histories.

Original languageEnglish (US)
Article number153247
JournalScience of the Total Environment
Volume820
DOIs
StatePublished - May 10 2022

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation : NSF GLD 1648772 . The manuscript was strengthened by feedback from four anonymous reviewers.

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

  • Basin sediment dynamics
  • Lake sediments
  • Legacy contamination
  • Mixing models
  • Trace metals
  • Yunnan Province

Continental Scientific Drilling Facility tags

  • CHIME

PubMed: MeSH publication types

  • Journal Article

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