After the Deepwater Horizon oil spill in 2010, toxicity tests were conducted using 4 microalgae (Dunaliella tertiolecta, Skeletonema costatum, Isochrysis galbana, and Thalassiosira pseudonana) and one macroalga (Ectocarpus siliculosus) to study potential impacts on phytoplankton and other primary producers in the Gulf of Mexico and characterize species sensitivity. Tests were performed with Corexit 9500 and fresh source oil and weathered oil samples collected from the field during the Deepwater Horizon oil spill. Because crude oils are mixtures of poorly water-soluble hydrocarbons, dosing was performed using water-accommodated fractions (WAFs) and chemically enhanced (CE) WAFs with the addition of dispersant at a 1:20 dispersant:oil ratio using standard toxicity testing protocols. Exposure media were analyzed for volatile organic compounds, parent and alkylated polycyclic aromatic hydrocarbons, and saturated hydrocarbon compounds. Toxicity was reported as no-observable effect concentration and median effect concentration (EC50) values for average specific growth rate based on nominal percent dilution of stock solution WAFs and sum of dissolved oil toxic units for WAF/CEWAF tests. The macroalga and green alga D. tertiolecta were largely unaffected by any WAF or CEWAFs tested. Isochrysis galbana was found to be the most sensitive species overall with significant growth rate inhibitions for dispersant and all the WAFs/CEWAFs tested. Physically dispersed source oils were generally more toxic than weathered oils. The protectiveness of the chronic toxic units was effective at identifying observed algal growth rate inhibitions across algal species and oil types despite the impact of dispersants. Environ Toxicol Chem 2021;40:2742–2754. © 2021 SETAC

中文翻译：

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海藻对源油和风化油的敏感性

2010年深水地平线漏油事件后，使用 4 种微藻（Dunaliella tertiolecta、Skeletonema costatum、Isochrysis galbana和Thalassiosira pseudonana）和一种大型藻类（Ectocarpus silculosus）进行了毒性测试，以研究对海湾浮游植物和其他初级生产者的潜在影响墨西哥和描述物种敏感性。使用 Corexit 9500 以及在深水地平线期间从现场采集的新鲜源油和风化油样品进行了测试漏油事件。由于原油是水溶性差的碳氢化合物的混合物，因此使用水容纳馏分 (WAF) 和化学增强 (CE) WAF 进行计量，并使用标准毒性测试协议以 1:20 的分散剂：油比添加分散剂。分析了暴露介质中的挥发性有机化合物、母体和烷基化多环芳烃以及饱和烃化合物。毒性报告为基于储备溶液 WAF 的标称稀释百分比和 WAF/CEWAF 测试的溶解油毒性单位总和的平均特定增长率的不可观察效应浓度和中值效应浓度 (EC50) 值。大藻和绿藻D. tertiolecta在很大程度上不受任何测试的 WAF 或 CEWAF 的影响。等鞭金藻被发现是最敏感的物种，对分散剂和所有测试的 WAF/CEWAF 具有显着的生长速率抑制作用。物理分散的源油通常比风化油毒性更大。尽管有分散剂的影响，慢性毒性单元的保护性在识别观察到的藻类和油类生长速率抑制方面是有效的。环境毒物化学2021；40:2742–2754。© 2021 SETAC