Polar Compounds Dominate in Vitro Effects of Sediment Extracts

Abstract

Sediment extracts from three polluted sites of the river Elbe basin were fractionated using a novel online fractionation procedure. Resulting fractions were screened for mutagenic, aryl hydrocarbon receptor (AhR)-mediated, transthyretin (TTR)-binding, and estrogenic activities and their potency to inhibit gap junctional intercellular communication (GJIC) to compare toxicity patterns and identify priority fractions. Additionally, more than 200 compounds and compound classes were identified using GC-MS/MS, LC-MS/MS, and HPLC-DAD methods. For all investigated end points, major activities were found in polar fractions, which are defined here as fractions containing dominantly compounds with at least one polar functional group. Nonpolar PAH fractions contributed to mutagenic and AhR-mediated activities while inhibition of GJIC and estrogenic and TTR-binding activities were exclusively observed in the polar fractions. Known mutagens in polar fractions included nitro-and dinitro-PAHs, azaarenes, and keto-PAHs, while parent and monomethylated PAHs such as benzo [a]pyrene and benzofluoranthenes were identified in nonpolar fractions. Additionally, for one sample, high AhR-mediated activities were determined in one fraction characterized by PCDD/Fs, PCBs, and PCNs. Estrone, 17β-estradiol, 9H-benz [de]anthracen-7-one, and 4-nonylphenol were identified as possible estrogenic and TTR-binding compounds. Thus, not only nonpolar compounds such as PAHs, PCBs, and PCDD/Fs but also the less characterized and investigated more polar substances should be considered as potent mutagenic, estrogenic, AhR-inducing, TTR-binding, and GJIC-inhibiting components for future studies.

Characterization of AhR agonist compounds in roadside snow

“…All these classes of compounds have also been found in the aromatic UCM fraction in UK estuary sediments, and several of them have been tested positive for mutagenic activity [35]. Some of the compounds identified with GCxGC-ToF-MS are known agonists of the AhR, for example 11H-benz(a)fluoren-11-one, 11H-benz(b)fluoren-11-one [36], methylpyrene and methylchrysene [37,38]. Others, like carbazole and dibenzothiophene, are CYP1A1 inhibitors [39], and these compounds can, to some extent, contribute to the total AhR activity of the samples.…”

Oxygenated, nitrated, methyl and parent polycyclic aromatic hydrocarbons in rivers of Haihe River System, China: Occurrence, possible formation, and source and fate in a water-shortage area

“…Wang et al (2011a) reported that the direct acting mutagenicity of Beijing particulate matter (PM) caused by the OPAHs and NPAHs was 2 times higher than that of the indirect mutagenicity caused by the PAHs, though the OPAH and NPAH concentrations only contributed 8% to the total PAH concentrations. In polluted river sediment, the fraction of the extracts containing the polar PAHs (including NPAHs) showed higher toxicities than those containing the non-polar PAHs like PAHs (Lübcke-von Varel et al, 2011). The OPAHs were weak inducers of in vitro estrogenic activity, similar to that of benzo [a]pyrene in river sediments (Machala et al, 2001).…”

PAHs (polycyclic aromatic hydrocarbons), nitro-PAHs, and hopane and sterane biomarkers in sediments of southern Lake Michigan, USA

“…While NPAHs were not detected in pond stations in the Twin Cities, MN, metropolitan area (Crane, 2014), NPAHs including 2-nitrofluorene, 1-nitropyrene and 6-nitrochrysene were detected at ppb to ppm levels in Varney Pond, White Bear Lake, MN (MDH, 2011). In Europe, NPAHs including nitronaphthalenes, 9-nitronaphthalene, 1-nitropyrene, 6-nitrochrysene and dinitropyrenes have been found at ppb levels in sediments from the Elbe River basin, Germany and Czech Republic (Lübcke-von Varel et al, 2012; Lubcke-von Varel et al, 2011). In sediments of the Suimon River, Japan, 1-nitropyrene and 2-nitrofulorene were measured at ppb levels (Sato et al, 1985).…”