Trace elements in coal ash

Fact Sheet 2015-3037
By: , and 



Coal ash is a residual waste product primarily produced by coal combustion for electric power generation. Coal ash includes fly ash, bottom ash, and flue-gas desulfurization products (at powerplants equipped with flue-gas desulfurization systems). Fly ash, the most common form of coal ash, is used in a range of products, especially construction materials. A new Environmental Protection Agency ruling upholds designation of coal ash as a non-hazardous waste under Subtitle D of the Resource Conservation and Recovery Act, allowing for the continued beneficial use of coal ash and also designating procedures and requirements for its storage.

In this fact sheet, the form, distribution, and behavior of trace elements of environmental interest in samples of coal fly ash were investigated in response to concerns about element mobility in the event of an ash spill. The study includes laboratory-based leaching experiments to examine the behavior of trace elements, such as arsenic (As) and chromium (Cr), in response to key environmental factors including redox conditions (degree of oxygenation), which are known to vary with depth within coal ash impoundments and in natural ecosystems. The experiments show that As dissolves from samples of coal fly ash into simulated freshwater under both oxic (highly oxygenated) and anoxic (poorly oxygenated) conditions, whereas dissolved Cr concentrations are very redox dependent. This U.S. Geological Survey research helps define the distribution of elements such as As in coal ash and shows that element mobility can vary considerably under different conditions expected in the environment.

Publication type Report
Publication Subtype USGS Numbered Series
Title Trace elements in coal ash
Series title Fact Sheet
Series number 2015-3037
DOI 10.3133/fs20153037
Year Published 2015
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Eastern Energy Resources Science Center
Description 6 p.
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details