GC AND GC-MS ANALYSIS OF POLYCHLORINATED DIOXINS, DIBENZOFURANS AND AROMATIC-HYDROCARBONS IN FLY-ASH FROM COAL-BURING WORKS

Carcinogenic and genotoxic polycyclic aromatic hydrocarbons (PAHs) were detected in coal fly ash samples. Further analysis of these samples also revealed the presence of highly toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The amount of PCDD/PCDF detected were in the parts per trillion (ppt) levels. Although coal fly ash contains a large number of organic compounds, the levels of PCDD/PCDF detected were two to three orders of magnitudes less than what has been observed in municipal solid waste incinerator (MSWI) fly ash samples. To investigate the probable reason for low levels of PCDD/PCDF in coal fly ash samples, catalytic activity tests were conducted using C-13 pentachlorophenol as the precursor. Results indicate that the formation mechanism of PCDD on coal fly ash is analogous to that on MSWI fly ash.