Toxicity testing of hydrophobic compounds with low aqueous solubility remains challenging. Dimethyl sulfoxide (DMSO) is widely used as a co-solvent for toxicity testing of hydrophobic chemicals, but it may modulate chemical toxicity patterns. In this study, we critically evaluated the suitability of DMSO as a co-solvent for toxicity testing of hydrophobic organic compounds in aqueous solutions. As the toxicity measure, we used growth inhibition of a natural bacterial community, and the test toxicants included phenol, BTEX (benzene, toluene, ethylbenzene and xylene) and transformation products of polycyclic aromatic hydrocarbons (PAHs). We found that dose-response curves for phenol were unaffected by DMSO concentrations up to 10% (v/v) and that DMSO (5% v/v) did not affect the degree of bacterial growth inhibition for any of the other test compounds in short-term experiments (3.5 h). By contrast, marked co-solvent effects of DMSO were observed in the long-term assay (25 and 27 h). We therefore conclude that DMSO has excellent co-solvent properties for short-term (≤3.5 h) toxicity testing of sparingly water-soluble compounds and its application provides a simple, inexpensive approach for screening of various environmentally relevant hydrophobic chemicals. Importantly, the use of DMSO allows for generation of full dose-responses that may otherwise not be attained.

中文翻译：

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评估二甲基亚砜（DMSO）作为疏水性有机化合物毒性测试的助溶剂。

低水溶性的疏水性化合物的毒性测试仍然具有挑战性。二甲基亚砜（DMSO）被广泛用作疏水性化学品毒性测试的助溶剂，但它可能会调节化学毒性模式。在这项研究中，我们严格评估了DMSO作为共溶剂用于水溶液中疏水性有机化合物毒性测试的适用性。作为毒性措施，我们使用了天然细菌群落的生长抑制作用，测试的有毒物质包括苯酚，BTEX（苯，甲苯，乙苯和二甲苯）和多环芳烃（PAHs）的转化产物。我们发现苯酚的剂量反应曲线不受浓度高达10％（v / v）的DMSO的影响，而DMSO（5％v / v）不会影响任何其他受试化合物中细菌生长抑制的程度。短期实验（3.5小时）。相比之下，在长期测定（25和27小时）中观察到了DMSO明显的助溶剂作用。因此，我们得出结论，DMSO对难溶于水的化合物的短期（≤3.5h）毒性测试具有出色的助溶剂性能，其应用为筛选各种与环境有关的疏水性化学品提供了一种简单，廉价的方法。重要的是，使用DMSO可以产生原本无法达到的全剂量反应。在长期测定（25和27小时）中观察到了DMSO显着的助溶剂作用。因此，我们得出结论，DMSO对难溶于水的化合物的短期（≤3.5h）毒性测试具有出色的助溶剂性能，其应用为筛选各种与环境有关的疏水性化学品提供了一种简单，廉价的方法。重要的是，使用DMSO可以产生原本无法达到的全剂量反应。在长期测定（25和27小时）中观察到了DMSO显着的助溶剂作用。因此，我们得出结论，DMSO对难溶于水的化合物的短期（≤3.5h）毒性测试具有出色的助溶剂性能，其应用为筛选各种与环境有关的疏水性化学品提供了一种简单，廉价的方法。重要的是，使用DMSO可以产生原本无法达到的全剂量反应。