PEAT INDUCES CYTOCHROME P450IA1 IN HEPA-1 CELL-LINE - COMPARISON WITHFLY ASHES FROM COMBUSTION OF PEAT, COAL, HEAVY FUEL-OIL AND HAZARDOUS-WASTE

When the effects of the products of various combustion processes - wit h coal, heavy fuel oil, peat or hazardous waste as a fuel - were compa red, an anomalous correlation between the biologically (induction of c ytochrome P450IA1 in the mouse hepatoma cell line Hepa-1) and the chem ically estimated ''TCDD equivalents'' was observed. The inducing effec t of the product from a peat combustion operation was stronger than th at of the product from hazardous waste combustion, although the chemic ally estimated TCDD equivalents were clearly lower in the former one. A more detailed study of two different peat combustion processes showe d that induction in one of the combustion processes was due to the ''l eakage'' of unburned peat to the fly ash. In the other process, no lea kage and no cytochrome P450IA1 induction was evident. This led us to a more detailed study of peat itself. One fraction of the peat extract was shown to be a very potent inducer of cytochrome P45OIA1. However, only small amounts of polychlorinated dibenzodioxins (PCDDs) or furans (PCDFs) were present in this fraction. It is thus evident that there are cytochrome P450IA1 inducers in peat other than those revealed by t he PCDD/PCDF analysis.