Many trace elements occur in coal, primarily as a part of the mineral matter but may also be associated with the organic matrix. Concern over release of certain trace elements to the environment as a result of coal utilization has made the determination of these elements an increasingly important aspect of coal analysis.

When coal ash is prepared in accordance with this test method, the eight elements listed in 1.1 are quantitatively retained in the ash and are representative of concentrations in the coal. Concentrations of these and other elements in power plant ash, industrial process ash, fly ash, and so forth, may or may not be representative of total quantities in the coal.