Effect directed analysis and mixture effects of estrogenic compounds in a sediment of the river Elbe

Abstract

The estrogenic effect of the organic sediment extract was determined using the yeast-estrogen-screen (YES). The sample was fractionated by liquid chromatography (LC) for effect directed analysis. The composition of estrogen-active fractions was further investigated by gas chromatography-mass spectrometry and high-resolution LC-MS analysis. The composition of the environmental sample was rebuilt with pure compounds in order to assess the partition of estrogenic activity caused by the identified compounds. The organic sediment extract showed an estrogenic potential of 1.9 ± 0.4 ng/g ethinylestradiol equivalents in the sediment. The most prominent contaminants with an estrogenic potential were 17β-estradiol, estrone, and 4-iso-nonylphenols, but other xenoestrogens like bisphenol A and stigmasterol could be found as well. A rebuild of the sample was measured in the YES in order to investigate mixture effects. About 67 % of the observed estrogenic effect in the sediment extract could be explained by a mixture which contained all identified compounds. Chlorophene (o-benzyl-p-chlorophenol)-a widely used antiseptic that was also identified in the sediment extract-has xenoestrogenic properties in the YES that are in the range of other xenoestrogens like 4-n-nonylphenol. This is the first report on chlorophene acting as a xenoestrogen.

Estrogenic effects along the river saale

“…The sites at Barby and Magdeburg receive substantial amounts of waste water via the river Saale from the cities Leipzig and Halle [5]. In accordance with this finding, several studies report the contamination of the river Elbe or its tributaries with (xeno)estrogens such as 4-alkylphenols, 4-alkylphenol ethoxylates, 4-alkylphenoxy carboxylates, bisphenol A, and dichlorodiphenyltrichloroethane metabolites [6][7][8][9]. All compounds listed tend to be adsorbed to suspended particulate matter and thus might contribute to sediment contamination.…”

“…Extraction of sediment and quantification of steroidal estrogens by coupled liquid chromatography-mass spectrometry The extraction procedure is described in detail in Schmitt et al [8]. Briefly, 10 g of the crunched sample was extracted with an ASE-100 accelerated solvent extractor (Dionex) in a 34 ml ASE cell at 1208C with 24 ml of a solvent mixture of 1:1 acetone : n-heptane at 118 bar.…”

“…The activity of the reporter enzyme b-galactosidase was determined by the absorption at 414 nm after addition of 100 ml/well 1 M Na 2 CO 3 . The estrogenic effect was expressed in terms of the induction rate according to Schmitt et al [8]. The measured absorbance at 414 nm that represents the activity of the reporter enzyme and thus the activation of the estrogen receptor is normalized to the cell density, which is determined by the absorption at 595 nm.…”

“…A dose-response relationship of the reference compound 17b-EE2 was measured in parallel to each assay. The ethinylestradiol equivalents (EEEQ) for each dilution level of each sample was calculated by a nonlinear interpolation [8,23,24] using the 17b-EE2 reference. The resulting EEEQ for each dilution level was multiplied with the respective dilution factor.…”

Evaluation of estrogenic activity in the Pearl River by using effect-directed analysis

“…Effect-directed analysis (EDA) has been proposed to solve this problem by using combined chemical analysis and bioassay based on fractionation (Campbell et al 2006;Brack et al 2008;Simon et al 2013). The EDA method has been successfully applied to determine toxicants responsible for some specific effects (Creusot et al 2013;Macova et al 2011;Regueiro et al 2013;Rostkowski et al 2011;Schmitt et al 2012;Yue et al 2015). Bioanalytical tools such…”