In vitro cellular responses in the RTG‐2 cell line to complex mixtures of dioxins and dioxin‐like PCDDs, PCDFs and PCBs

High‐resolution gas chromatography/mass spectrometry (HRGC/MS) is the standard method for analysing dioxin, furan and polybrominated retardants in hazardous waste. Determination of dioxin‐like compounds using in vitro bioassays such as ethoxyresorufin‐ O ‐deethylase (EROD) is an important tool to evaluate their Ah receptor‐mediated toxic effects, because it detects all arylhydrocarbon receptor ligands in a variety of sample matrices. In the present work, we compared RTG‐2 cell line EROD bioassay with HRGC/MS for assessing waste samples (liquid and solid) contaminated with polychlorinated dibenzo‐ p ‐dioxins and dibenzofurans, polychlorinated biphenyls (dioxin‐like PCBs) and other xenobiotics. For liquid samples, HRGC/MS‐toxic equivalent (HRGC/MS‐TEQ) values ranged from 273.26 to 5.84 ng TEQ l −1 and correlated well (correlation coefficient 0.99) with values obtained by EROD‐TEQ, which ranged from 128 to 2.5 ng TEQ l −1 . For solid samples, HRGC/MS‐TEQ values ranged from 3.44 to 0.49 ng TEQ g −1 and correlated less well than liquid samples (correlation coefficient 0.64) with values obtained by EROD‐TEQ ranging from 2.27 to 0.93 ng TEQ g −1 . The overestimation of RTG‐2 EROD‐TEQ (1.2 ± 0.92 of values established by HRGC/MS) and the absence of false‐negative results may limit analytical costs by eliminating the need for follow‐up GC/MS analysis on the negative samples. We suggest that RTG‐2 EROD bioassay is an inexpensive means for preliminary dioxin and furan positive screenings of waste samples. Copyright © 2010 John Wiley & Sons, Ltd.