Boron and strontium isotopic characterization of coal combustion residuals: Validation of new environmental tracers

Laura S. Ruhl, Gary S. Dwyer, Heileen Hsu-Kim, James C. Hower, Avner Vengosh

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

In the U.S., coal fired power plants produce over 136 million tons of coal combustion residuals (CCRs) annually. CCRs are enriched in toxic elements, and their leachates can have significant impacts on water quality. Here we report the boron and strontium isotopic ratios of leaching experiments on CCRs from a variety of coal sources (Appalachian, Illinois, and Powder River Basins). CCR leachates had a mostly negative δ11B, ranging from -17.6 to +6.3‰, and 87Sr/86Sr ranging from 0.70975 to 0.71251. Additionally, we utilized these isotopic ratios for tracing CCR contaminants in different environments: (1) the 2008 Tennessee Valley Authority (TVA) coal ash spill affected waters; (2) CCR effluents from power plants in Tennessee and North Carolina; (3) lakes and rivers affected by CCR effluents in North Carolina; and (4) porewater extracted from sediments in lakes affected by CCRs. The boron isotopes measured in these environments had a distinctive negative δ11B signature relative to background waters. In contrast 87Sr/86Sr ratios in CCRs were not always exclusively different from background, limiting their use as a CCR tracer. This investigation demonstrates the validity of the combined geochemical and isotopic approach as a unique and practical identification method for delineating and evaluating the environmental impact of CCRs.

Original languageEnglish
Pages (from-to)14790-14798
Number of pages9
JournalEnvironmental Science & Technology
Volume48
Issue number24
DOIs
StatePublished - 16 Dec 2014
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry (all)
  • Environmental Chemistry

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