Functional Predictor Variables for the Leaching Potential of Arsenic and Selenium from Coal Fly Ash

Zehao Jin, Jie Ren, Nelson A. Rivera, James C. Hower, Heileen Hsu-Kim

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The release of leachates from intact coal ash impoundments is a concern due to the enrichment and mobilization of toxic elements such as arsenic (As) and selenium (Se). This study aims to explore the intrinsic properties of coal fly ash that correlate with the relative leachability of As and Se. We performed leaching experiments with 52 fly ash samples collected from 15 different U.S. power plants and representing coal feedstocks from the three major domestic regions. We assessed the mobilization potential of As and Se in fly ash based on standardized leaching protocols and performed multivariate and lasso regression analyses to explore correlations of leachable As and Se contents with characteristics such as major element contents, loss on ignition, and pH. The results of regression models indicated that major elements (Fe, Ca, and Al) for a wide range of fly ashes can serve as predictor variables for the leaching potential of As but not for Se. LOI and pH were not important predictive variables in the models. Both regression approaches resulted in relatively strong fits for leachable As (correlation coefficient R2 = 0.78 for both models) compared to models for leachable Se (R2 = 0.49). Overall, these results suggest that correlation models combined with on-site elemental analysis with portable analyzers may enable a screening method for leachable As in coal ash.

Original languageEnglish
Pages (from-to)1105-1115
Number of pages11
JournalACS ES and T Water
Issue number4
StatePublished - Apr 14 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.


  • coal combustion residues
  • leachable trace elements
  • leaching environmental assessment framework (LEAF)
  • toxicity characteristic leaching protocol (TCLP)
  • waste characterization and management

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Chemical Engineering (miscellaneous)
  • Environmental Chemistry
  • Water Science and Technology


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