Receptor-mediated estrogenicity of native and chemically dispersed crude oil determined using adapted microscale reporter gene assays. (January 2020)

• Record Type: Journal Article
• Authors: Johann, Sarah; Esser, Milena; Nüßer, Leonie; Altin, Dag; Hollert, Henner; Seiler, Thomas-Benjamin
• Is Part Of: Environment international. Volume 134(2020)
• Publication Date: 2020-01
• Subjects: Crude oil -- Dispersant -- Endocrine disruption -- Estrogen receptor -- In vitro -- WAF; EDC endocrine disrupting compounds -- ERα estrogen receptor α -- ERα-CALUX® ERα-chemical-activated luciferase gene expression -- AYES® Arxula-Yeast Estrogen Screen -- (LE/CE/HE)-WAF low energy/chemically enhanced/high energy water-accommodated fractions -- NNS crude oil naphthenic North Sea crude oil -- PAH polycyclic aromatic compounds -- SOP standard operation procedure -- GC gas chromatography -- BDS BioDetection Systems -- POP persistent organic pollutants; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2019.105320
• Languages: English
• ISSNs: 0160-4120

Abstract

Graphical abstract: Highlights: Validated microscale assays on estrogenicity were optimized for petroleum toxicity testing. Bioassays were highly sensitive towards WAF exposure in brackish and freshwater conditions. Native and chemically dispersed crude oil WAFs did activate the ERα. The dispersant itself had a limited influence on high CEWAF activity. Metabolization of WAF compounds did not change the estrogenic activity. Abstract: Endocrine disrupting compounds (EDCs) emerged as a major concern for water quality in the last decade and have been studied extensively since. Besides typical natural and synthetic estrogens also petroleum product compounds such as some PAHs have been identified as potential EDCs, revealing endocrine disruption to be a relevant mode of action for crude oil toxicity. Hence, in the context of a comprehensive retro- or prospective risk assessment of oil spills the implementation of mechanism-specific toxicity such as endocrine disruption is of high importance. To evaluate the exposure risk for the aquatic biota, research focuses on water-soluble fractions underlying an oil slick that could be simulated via water-accommodated fractions (WAF). Against this background human (ERα-CALUX®) and yeast based (A-YES®) reporter gene bioassays were successfully optimized for the application in estrogenicity evaluation of the water-accommodated fraction (WAF) from a crude oil. Combining different approaches, the estrogenicity of the WAFs from a naphthenic North Sea crude oil was tested with and without the addition of a chemical dispersant addressing specific aspects of estrogenicity including the influence of biotransformation capacities and different salinity conditions. Both the WAF free from droplets (LEWAF) as well as the chemically dispersed WAF (CEWAF) gave indications of an ER-mediated estrogenicity with much stronger ERα agonists in the CEWAF treatment. Resulting estradiol equivalents of the WAFs were above the established effect-based trigger values for both bioassays. Results indicate that the dispersant rather increased the fraction of ER-activating crude oil compounds instead of interacting with the receptor itself. Only slight changes in estrogenic responses were observed when cells capable of active metabolism (T47D) were used instead of cells without endogenous metabolism (U2-OS) in the recombinant ER transactivation CALUX assay. With the yeast cells a higher estrogenic activity was observed in the experiments under elevated salinity conditions (6‰), which was in contrast to previous expectations due to typical decrease in dissolved PAH fraction with increasing salinity (salting-out effect) but might be related to increased cell sensitivity.