Environmental mixtures of chemicals consist of a countless number of compounds with unknown identity and quantity. Yet, chemical regulation is mainly built around the assessment of single chemicals. Existing frameworks for assessing the toxicity of mixtures require that both chemical composition and quantity are known. Quantitative analyses of the chemical composition of environmental mixtures are however extremely challenging and resource-demanding. Bioassays may therefore serve as a useful approach for investigating the combined toxicity of environmental mixtures of chemicals in a cost-efficient and holistic manner. In this study, an unknown environmental mixture of bioavailable semi-hydrophobic to hydrophobic chemicals was sampled from a contaminated sediment in a coastal Baltic Sea area using the silicone polydimethylsiloxane (PDMS) as equilibrium passive sampler. The chemical mixture was transferred to a PDMS-based passive dosing system, and its applicability was demonstrated using the green algae Tetraselmis suecia in a cell viability assay. The proportion of dead cells increased significantly with increasing exposure level and in a dose-response manner. At the ambient concentration, the proportion of dead cells in the population was nearly doubled compared to the control; however, the difference was non-significant due to high inter-replicate variability and low number of the replicates. The validation of the test system regarding equilibrium sampling, loading efficiency to the passive dosing polymer, stability of the mixture composition, and low algal mortality in control treatments demonstrates that combining equilibrium passive sampling and passive dosing is a promising tool for investigating the toxicity of bioavailable semi-hydrophobic and hydrophobic chemicals in complex environmental mixtures.

中文翻译：

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使用基于硅酮的被动采样和定量给料将化学混合物从沉积物中转移到生物测定中

化学物质的环境混合物由数不清的未知身份和数量的化合物组成。然而，化学法规主要围绕对单一化学物质的评估而建立。现有的评估混合物毒性的框架要求同时知道化学成分和数量。然而，对环境混合物的化学成分进行定量分析极具挑战性，并且对资源的需求很大。因此，生物测定法可以作为一种有用的方法，以经济高效和整体的方式研究化学环境混合物的综合毒性。在这项研究中，使用有机硅聚二甲基硅氧烷（PDMS）作为平衡被动采样器，从波罗的海沿岸地区受污染的沉积物中采样了未知的生物可利用的半疏水性与疏水性化学物质的环境混合物。将化学混合物转移至基于PDMS的被动加药系统，并在细胞活力测定中使用绿藻Tetraselmis suecia证明了其适用性。死亡细胞的比例随着暴露水平的增加和剂量反应的方式而显着增加。在环境浓度下，死细胞在种群中的比例与对照相比几乎增加了一倍；但是，由于复制品之间的变异性高且复制品数量少，因此差异不显着。关于平衡采样的测试系统的验证，