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) wer e detected in coal fly ash samples. Further analysis of these samples also revealed the presence of highly toxic polychlorinated dibenzo-p-d ioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The amount o f PCDD/PCDF detected were in the parts per trillion (ppt) levels. Alth ough coal fly ash contains a large number of organic compounds, the le vels of PCDD/PCDF detected were two to three orders of magnitudes less than what has been observed in municipal solid waste incinerator (MSW I) fly ash samples. To investigate the probable reason for low levels of PCDD/PCDF in coal fly ash samples, catalytic activity tests were co nducted using C-13 pentachlorophenol as the precursor. Results indicat e that the formation mechanism of PCDD on coal fly ash is analogous to that on MSWI fly ash.