Marine organisms are constantly exposed to complex chemical mixtures from natural and anthropogenic sources. One source that has raised concerns is the discharge water from ships equipped with exhaust gas cleaning systems, commonly known as scrubbers. During operation, ships with scrubbers discharge large volumes of scrubber water, known to adversely affect marine organisms, into the environment. Scrubber water is highly acidic and contains a complex mixture of contaminants, including metals and polycyclic aromatic hydrocarbons (PAHs), at high concentrations. To assess the effect from these mixtures, critical values for individual mixture components can be determined from ecotoxicological studies and then compared to measured exposure concentrations. However, for several substances identified in scrubber water, for instance many alkylated PAHs, ecotoxicological studies are unavailable, preventing the determination of critical values. In this study, Quantitative Structure-Activity Relationship (QSAR) models have been used to amend and complement experimental data to estimate the mixture toxicity of scrubber water. Our results show that the combined predicted ecotoxicological response of an amended list of 50 substances measured in scrubber water from the substance groups metals (n=10), PAHs (n=16) and their alkylated derivatives (n=24), still underestimates the response observed in whole effluent toxicity tests. This suggests that there are additional substances and/or synergistic effects in the scrubber water mixtures that contribute to the overall toxicity. Thus, to accurately describe the toxicity of scrubber water, measurements and toxicity assessments must extend far beyond the usual suspects of 16 PAHs and a limited selection of metals. Here, QSAR models and advanced chemical screening-based methods are valuable tools for identifying substances of concern.

中文翻译：

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应用定量构效关系 （QSAR） 模型扩展洗涤器水的混合物毒性预测


海洋生物经常暴露在来自自然和人为来源的复杂化学混合物中。引起担忧的一个来源是配备废气净化系统（通常称为洗涤器）的船舶的排放水。在运行过程中，带有洗涤器的船舶将大量洗涤器水排放到环境中，这些水已知会对海洋生物产生不利影响。洗涤器水是高酸性的，含有复杂的污染物混合物，包括高浓度的金属和多环芳烃 （PAH）。为了评估这些混合物的影响，可以通过生态毒理学研究确定单个混合物成分的临界值，然后与测得的暴露浓度进行比较。然而，对于洗涤器水中鉴定出的几种物质，例如许多烷基化 PAH，无法进行生态毒理学研究，因此无法确定临界值。在本研究中，定量构效关系 （QSAR） 模型被用于修正和补充实验数据，以估计洗涤器水的混合毒性。我们的结果表明，在洗涤器水中测量的 50 种物质的修订清单中，来自物质组金属 （n=10）、多环芳烃 （n=16） 及其烷基化衍生物 （n=24） 的综合预测生态毒理学响应，仍然低估了在整个污水毒性测试中观察到的反应。这表明洗涤器水混合物中存在其他物质和/或协同效应，这些物质和/或协同效应会导致整体毒性。因此，为了准确描述洗涤器水的毒性，测量和毒性评估必须远远超出通常的 16 种 PAH 和有限的金属选择。 在这里，QSAR 模型和基于化学筛选的先进方法是识别关注物质的宝贵工具。