Characterization of aryl hydrocarbon receptor agonists in sediments of Wenyu River, Beijing, China

Abstract

PAHs H4IIE Sediment a b s t r a c tAryl hydrocarbon receptor agonistic (Ah-agonistic) effects of 23 sediments from Wenyu River in Beijing, China were evaluated using the H4IIE cell bioassay. Five samples were selected for chemical analysis of most concerned Ah-agonists, i.e. polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). All raw sediment extracts induced significant Ah-agonistic effects, and the bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents of raw extracts (TEQ raw s) ranged from 8.5 to 336.0 pg/g dry weight (dw). Chemical analysisderived TEQs (TEQ chem s) ranged from 20.5 to 64.8 pg/g dw. When raw extracts were purified by sulphuric acid silica gel column to derive acid stable fraction, the TCDD equivalents in this fraction (TEQ stable s) ranged from 2.7 to 63.8 pg/g dw. PCBs, PCDDs and PCDFs contributed about 51.4-72.1%, 1.2-7.3%, and 16.4-34.8% of TEQ stable s, respectively, and the sum was 69.1-108.6%. Therefore, about 65.0% of TEQ raw s could be attributed to acid labile fraction and only 3.3-9.6% to PAHs. These observations suggested that acid stable fraction and labile fraction contributed together to total Ah-agonistic effects in the sediments, and PCBs and PCDFs might be the two main components in acid stable Ah-agonists. The proposed approach using both H4IIE cell bioassay and chemical analysis could be used for characterization and prioritization of Ah-agonists in river sediments and helpful to the following progression of ecological remediation. ª 2009 Elsevier Ltd. All rights reserved. IntroductionAryl hydrocarbon receptor agonists (Ah-agonists), which include structurally diverse synthetic and naturally-occurring chemicals, are ubiquitous in the environment (Denison et al., 2002). Ah-agonists share a common mechanism of action in binding to the Ah receptor as a first step, and toxicities are produced as a result of changes in gene expression mediated Ah receptor or interference in its related signaling pathways (Safe, 1990). In the past decades, the major concerns on Ahagonistic effects were associated with dioxins and dioxin-like compounds which mainly referred to polyhalogenated aromatic hydrocarbons (PHAHs) including polychlorinated dibenzo-pdioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), naphthalenes (PCNs) and others (reviewed by Behnisch et al., 2001). These compounds have been shown to produce a number of toxic effects upon wildlife and human health due to both the persistent behavior and ability to bioaccumulate (Van den Berg w a t e r r e s e a r c h 4 3 ( 2 0 0 9 ) 2 4 4 1 -2 4 4 8

Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

“…There were no great differences between the EROD values among the ten sediment samples, indicating that AhR agonists were distributed rather homogeneously in TGR from Wanzhou to the great dam. The determined EROD TCDD EQ (bio-TEQ) amounts in the present study are comparable with ERODinducing potentials of sediments reported by some other studies, including sediments collected from harbors along the Dutch coast ranging from 0.2 to 136 pg TCDD EQ g −1 dw (Stronkhorst et al 2002) and from Osaka Bay, Japan with 3.7 to 140 pg TCDD g −1 dw (Takigami et al 2005) tested with H4IIE-luc hepatoma cell line after 24 h of exposure, as well as sediments collected from Wenyu River, China with 15 to 64 pg TCDD g −1 tested with H4IIE hepatoma cell line after 72 h of exposure (Luo et al 2009) and from Yeongil Bay, Korea ranging from 2.8 to 320 pg TCDD g −1 dw tested with H4IIE-luc hepatoma cell line after 72 h of exposure (Koh et al 2006). On the other hand, the EROD bio-TEQ amounts reported in our study are higher than those reported in sediments from west coast of South Korea with non-detectable to 11 pg TCDD g −1 dw and north coast of Bohai Sea, China with nondetectable to 28 pg TCDD g −1 dw (Hong et al 2012) and sediments from Meiliang Bay, Lake Taihu before the ecological remediation project ranging from 17.8 to 38.5 pg TCDD g −1 dw (Qiao et al 2009) which were all tested with H4IIE rat hepatoma cells after 72 h of exposure.…”