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In vitro tools for the toxicological evaluation of sediments and dredged materials: intra- and inter-laboratory comparisons of chemical and bioanalytical methods

Eichbaum, Kathrin, Brinkmann, Markus, Nuesser, Leonie, Gembé, Carolin, Ohlig, Marina, Buchinger, Sebastian, Reifferscheid, Georg, Hecker, Markus, Giesy, John P., Hollert, Henner
Environmental science and pollution research international 2018 v.25 no.5 pp. 4037-4050
batteries, bioassays, cell lines, detection limit, dredged materials, guidelines, mass spectrometry, risk assessors, rivers, screening, toxicity, toxicity testing
The implementation of in vitro bioassays for the screening of dioxin-like compounds (DLCs) into management guidelines of dredged material is of increasing interest to regulators and risk assessors. This study reports on an intra- and inter-laboratory comparison study between four independent laboratories. A bioassay battery consisting of RTL-W1 (7-ethoxy-resorufin-O-deethylase; EROD), H4IIE (micro-EROD), and H4IIE-luc cells was used to assess aryl hydrocarbon receptor-mediated effects of sediments from two major European rivers, differently contaminated with DLCs. Each assay was validated by characterization of its limit of detection (LOD) and quantification (LOQ), z-factor, reproducibility, and repeatability. DLC concentrations were measured using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) and compared to bioassay-specific responses via toxicity equivalents (TEQs) on intra- and inter-laboratory levels. The micro-EROD assay exhibited the best overall performance among the bioassays. It was ranked excellent (z-factor = 0.54), reached a repeatability > 75%, was highly comparable (r ² = 0.87) and reproducible (83%) between two laboratories, and was well correlated (r ² = 0.803) with TEQs. Its LOD and LOQ of 0.5 and 0.7 pM 2,3,7,8-TCDD, respectively, approached LOQs of HRGC/HRMS measurements. In contrast, cell lines RTL-W1 and H4IIE-luc produced LODs > 0.7 pM 2,3,7,8-TCDD, LOQs > 1.7 pM 2,3,7,8-TCDD, and repeatability < 70%. Based on the data obtained, the micro-EROD assay is the most favorable bioanalytical tool, and via a micro-EROD-based limit value, it would allow for the assessment of sediment DLC concentrations; thus, it could be considered for the implementation into testing and management guidelines for dredged materials.