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>Low-temperature thermal decomposition of dioxin-like compounds in fly ash: combination of chemical analysis with in vitro bioassays (EROD and DR-CALUX)
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Low-temperature thermal decomposition of dioxin-like compounds in fly ash: combination of chemical analysis with in vitro bioassays (EROD and DR-CALUX)
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机译：Low-temperature thermal decomposition of dioxin-like compounds in fly ash: combination of chemical analysis with in vitro bioassays (EROD and DR-CALUX)
To investigate the dechlorination of fly ash during low-temperature treatment under oxygen-deficient conditions (thermocatalytic treatment or Hagenmaier process), six fly ash samples from six different incineration plants were treated in a laboratory experiment or in the actual plant, either under ideal (400 ℃, 120 min) or intermediate (300 ℃, 30 min) conditions. The aim of the present study was to confirm the decrease in the I-TEQ (international toxicity equivalency) of polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs) and coplanar polychlorinated biphenyls (co-PXBs) and, also forthe first time, the decrease in the sum of dioxin-like toxicity (bioassay- or bio-TEQ) of all kinds of other dioxin-like Ah receptor agonists (such as PXDD/Fs, PXBs, PXN, X = Br, F) measured by two state-of-the-art cell-based Ah receptor-dependent bioassays: H4IIE-Ethoxy-Resorufin-o-Deethylase (EROD) and H4IIE-luc/DR-Chemical Activated Luciferase expression (DR-CALUX). The treatment efficiency was calculated on the basis of the reduction in the I-TEQ and bio-TEQ values. For these fly ash samples, the treatment efficiency, as measured by chemical analysis, was higher than 99, and 85-99, in the case of the bio-TEQ values, indicating that these Ah receptor binding toxic compounds were sufficiently decomposed. Bio-TEQ values for untreated fly ash samples (n = 6) were on average 1.2 times (range 0.7-1.9), for the H4IIE-EROD assay, and 2.8 times (1.1-4.9), for the DR-CALUX assay, higher than I-TEQ values measured by chemical analyses (sum of PCDD/Fs and co-PCBs). In the case of these fly ash samples treated under ideal conditions and therefore low in contaminants, the bio-TEQ values were on average 1.4 times (range 0.9-1.8), for the H4IIE-EROD assay, and 5.1 times (range 1.2-12), for the DR-CALUX assay, higher than the I-TEQ values.
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