Unsubstituted polyaromatic hydrocarbons (PAH's) in extracts of coal fly ash from the fly ash test cell in Montour, Pennsylvania.

摘要

Isotope Dilution Mass Spectrometry (IDMS) was used to identify and to quantify trace amounts of selected, unsubstituted polyaromatic hydrocarbons (PAH's) present in extracts of coal fly ash from the solid waste disposal test cell at Montour, Pennsylvania. Isotope dilution experiments using deuterated analogs of polyaromatic hydrocarbons demonstrated that the concentrations of benzo (a) pyrene and anthracene were lower than 1 ng/g of fly ash. Isotope dilution experiments demonstrated that benzo (a) pyrene could be detected at concentrations as high as 1 ng/g when an isotopic carrier was used at a concentration of 125 ng/g in the analytical method. An isotopic carrier was not required for any of the selected polyaromatic hydrocarbons except benzo (a) pyrene. Maximum concentrations of fluorene, fluoranthene, pyrene and chrysene were conservatively estimated to be 3 ng/g of fly ash, using a 95 percent confidence interval based on analytical precision of {dollar}pm{dollar}1 ng/g of fly ash. Concentrations of phenanthrene were found to range from 6 to 38 ng/g of fly ash with a mean concentration of 14 ng/g of fly ash. No correlations were found between concentrations of phenanthrene and the position, depth or time of weathering of fly ash samples taken from the coal fly ash test cell. No evidence was found for any concentration gradient of phenanthrene in the test cell. Two sources of phenanthrene were speculated: incomplete combustion of phenanthrene in the coal furnace and addition of phenanthrene to the fly ash after collection by electrostatic precipitators.; Control experiments demonstrated that the analytical method was accurate and precise for the determination of polyaromatic hydrocarbons at concentrations of 1 ng/g of fly ash. Analytical precision was {dollar}pm{dollar}1 ng/g of fly ash, based on determinations of phenanthrene in replicate samples of fly ash. Analytical limits of detection ranged from 0 to 4 ng/g of fly ash.