Zinc Isotopic Signatures in Eight Lake Sediment Cores from across the United States


Zinc is an important trace element pollutant in urban environments; however, the extent of Zn contamination and the sources of urban Zn pollution are often unclear. We measured Zn concentrations and isotopes in sediment cores collected from eight lakes or reservoirs across the United States. We paired these data with historical records of land use within each watershed to calculate a mean Zn concentration and δ66Zn for natural (less than 5% urban land use; 123 ± 21.7 mg/kg; +0.33 ± 0.08‰, n = 6 lakes) and urban (greater than 70% urban land use; 389 ± 200 mg/kg; +0.14 ± 0.07‰, n = 3 lakes) lake sediments. The relation between Zn concentration data and Zn isotope data allows us to create a mixing model between two end members: natural and urban. The δ66Zn of the urban end-member is consistent with Zn pollution from vehicle-related sources (tire wear and emissions). Application of this model to samples collected from lakes recording periods ranging from 5 to 70% urban land use in their surrounding watersheds indicates that the lakes and reservoirs were affected by large amounts of Zn from urban sources.


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Isotopes; Land use; Pollution; Reservoirs (water); Sedimentation; Trace elements; Zinc; Concentration data; Historical records; Isotopic signatures; Lake sand reservoirs; Lake sediment cores; Lake sediments; Urban environments; Urban land use; Lake pollution; isotope; trace element; anthropogenic effect; pollution monitoring; sediment core; urban pollution; agricultural land; atmospheric deposition; combustion; electroplating industry; population density; residential area; rock; sedimentation rate; soil; United States; urban area; urbanization; vaporization; watershed; analysis; city; comparative study; environmental monitoring; Environmental Pollution; Geologic Sediments

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Article - Journal

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© 2015 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Jan 2015