Evaluation of planar halogenated and polycyclic aromatic hydrocarbons in estuarine sediments using ethoxyresorufin-O-deethylase induction of H4IIE cells

Polycyclic aromatic hydrocarbons (PAHs) and planar halogenated hydrocarbons (PAHs), including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were determined in fractionated sediment ext racts from the Hudson-Raritan estuary and Newark Bay, New Jersey, USA, as p art of a comprehensive risk assessment. Contributions of PCDDs/PCDFs, PCBs, and PAHs to the total toxic equivalents (TEQs) were measured using an H4II E bioassay and calculated from instrumentally determined concentrations usi ng international toxic equivalency factors. The H4IIE TEQs of whole and fra ctionated extracts were compared to calculated TEQs to investigate the appl icability of the bioassay approach for evaluating 7-ethoxyresorufin-O-deeth ylease induction by PHHs and PAHs present together in complex mixtures. Alt hough 2,3,7,8-tetrachlorodibenzo-p-dioxin contributed from 41 to 79% of the calculated TEQs from PCDDs/PCDFs and planar PCBs in all sediments sampled, the PAM-containing fractions accounted for >80% of the total TEQs determin ed either instrumentally or by bioassay. Calculated TEQs from PAHs, based o n reported toxic equivalency factors for only seven PAHs, were severalfold greater than the bioassay-derived TEQs of PAM-only fractions of the sedimen t extracts. Significant correlations were observed between bioassay and ins trumentally determined toxic equivalents in the more purified fractions but not in fractions only purified by size-exclusion or argentate chromatograp hies alone.