Zn and Cu Isotopes As Tracers of Anthropogenic Contamination in a Sediment Core from an Urban Lake

Abstract

In this work, we use stable Zn and Cu isotopes to identify the sources and timing of the deposition of these metals in a sediment core from Lake Ballinger near Seattle, Washington, USA. The base of the Lake Ballinger core predates settlement in the region, while the upper sections record the effects of atmospheric emissions from a nearby smelter and rapid urbanization of the watershed. δ66Zn and δ65Cu varied by 0.50‰ and 0.29‰, respectively, over the 500 year core record. Isotopic changes were correlated with the presmelter period (~1450 to 1900 with δ66Zn = +0.39‰ ± 0.09‰ and δ65Cu = +0.77‰ ± 0.06‰), period of smelter operation (1900 to 1985 with δ66Zn = +0.14 ± 0.06‰ and δ65Cu = +0.94 ± 0.10‰), and postsmelting/stable urban land use period (post 1985 with δ66Zn = 0.00 ± 0.10‰ and δ65Cu = +0.82‰ ± 0.12‰). Rapid early urbanization during the post World War II era increased metal loading to the lake but did not significantly alter the δ66Zn and δ65Cu, suggesting that increased metal loads during this time were derived mainly from mobilization of historically contaminated soils. Urban sources of Cu and Zn were dominant since the smelter closed in the 1980s, and the δ66Zn measured in tire samples suggests tire wear is a likely source of Zn.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Anthropogenic contamination; Atmospheric emission; Contaminated soils; Metal loadings; Seattle; Washington; Sediment core; Tire wear; Urban lake; Urban land use; World war II; Air pollution; Isotopes; Lake pollution; Lakes; Land use; Sedimentology; Smelting; Soil pollution; Zinc; copper; copper 66; isotope; trace element; unclassified drug; zinc; zinc 66; anthropogenic source; copper; lacustrine deposit; sediment core; sediment pollution; smelting; soil pollution; stable isotope; tracer; urbanization; watershed; zinc; concentration (parameters); controlled study; lake sediment; land use; smelter; soil; United States; urban area; urbanization; war; water contamination; watershed; Copper; Environmental Monitoring; Fresh Water; Geologic Sediments; Humans; Isotopes; Time Factors; Trace Elements; Urban Health; Urbanization; Water Pollutants; Chemical; Zinc Isotopes; United States; Washington [United States]

International Standard Serial Number (ISSN)

0013-936X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2010 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Feb 2010

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