School of Environment and Sustainability (SENS), University of Saskatchewan, 44 Campus Drive, Saskatoon S7N 5C8, Canada.
Toxicology Centre, University of Saskatchewan, Saskatoon S7N 5B3, Canada.
Environ Sci Technol. 2020 Aug 4;54(15):9547-9555. doi: 10.1021/acs.est.0c02522. Epub 2020 Jul 19.
Uptake and effects of ionizable organic chemicals (IOCs) that are weak acids in aqueous solution by fish can differ as a function of pH. While the pH-dependent behavior of select IOCs is well-understood, complex mixtures of IOCs, e.g., from oil sands process-affected water (OSPW), have not yet been studied systematically. Here, we established an in vitro screening method using the rainbow trout gill cell line, RTgill-W1, to investigate pH-dependent cytotoxicity and permeation of IOCs across cultured epithelia using ultra-high-performance liquid chromatography with high-resolution mass spectrometry (UPLC-HRMS). The assay was benchmarked using model chemicals and technical mixtures, and then used to characterize fractions and reconstituted extracts of field-collected OSPW. Significant pH-dependent cytotoxicity of individual IOCs, acidic fractions, and reconstituted extracts of OSPW was observed. In vitro data were in good agreement with data from a 96 h in vivo exposure experiment with juvenile rainbow trout. Permeation of some IOCs from OSPW was mediated by active transport, as revealed by studies in which inhibitors of these active transport mechanisms were applied. We conclude that the RTgill-W1 in vitro assay is useful for the screening of pH-dependent uptake of IOCs in fish, and has applications for in vitroin vivo extrapolation, and prioritization of chemicals in nontarget screenings.
在水溶液中，作为弱酸的可电离有机化学品（IOCs）被鱼类吸收并产生影响的情况会随 pH 值而变化。虽然某些特定 IOC 的 pH 依赖性行为已得到充分研究，但复杂的 IOC 混合物，例如油砂加工影响水（OSPW）中的混合物，尚未得到系统研究。在这里，我们使用虹鳟鱼鳃细胞系 RTgill-W1 建立了一种体外筛选方法，使用超高效液相色谱-高分辨率质谱（UPLC-HRMS）研究 IOCs 在培养的上皮细胞中跨膜的 pH 依赖性细胞毒性和通透性。该方法使用模型化学品和技术混合物进行了基准测试，然后用于表征野外采集的 OSPW 的馏分和重建提取物。观察到个别 IOC、酸性馏分和 OSPW 重建提取物的显著 pH 依赖性细胞毒性。体外数据与幼虹鳟鱼 96 小时体内暴露实验的数据非常吻合。OSPW 中一些 IOC 的渗透是由主动转运介导的，这是通过应用这些主动转运机制抑制剂的研究揭示的。我们得出结论，RTgill-W1 体外测定法可用于筛选鱼类中 IOC 的 pH 依赖性吸收，适用于体外-体内外推法以及非靶标筛选中化学品的优先级排序。
