Environ Toxicol Chem. 2014 Jan;33(1):107-14. doi: 10.1002/etc.2397.
Atlantic herring (Clupea harengus) embryos were exposed to water accommodated fractions (WAFs; oil dissolved in water) and chemically enhanced water accommodated fractions (CEWAFs; oil dispersed in water with Corexit 9500A) of Medium South American (MESA) crude oil. The CEWAF was approximately 100-fold more toxic than WAF based on nominal loadings of test solutions (% v/v). In contrast, the ratio of WAF and CEWAF toxicity expressed as measured oil concentrations approximated 1.0, indicating that the higher toxicity of CEWAFs was caused by an increase in exposure to hydrocarbons with chemical dispersion. In a second experiment, the chronic toxicity of Corexit 9500A and chemically dispersed heavy fuel oil 7102 (HFO 7102) to rainbow trout (Oncorhynchus mykiss) embryos was compared to chemically dispersed Nujol, a nontoxic mineral oil. Dispersant alone was toxic, but caused different signs of toxicity than HFO 7102. Nujol at a dispersant-to-oil ratio of 1:20 was nontoxic, suggesting that dispersant was sequestered by oil and not present at toxic concentrations. In contrast, the same nominal loadings of dispersed HFO 7102 caused concentration-dependent increases in toxicity. Both experiments suggest that chemically dispersed oil was more toxic to fish embryos than solutions created by mechanical mixing due to the increased exposure of fish to petroleum hydrocarbons and not to changes in hydrocarbon toxicity. The Nujol control discriminated between the toxicity of oil and chemical dispersant and would be a practical addition to programs of dispersant testing.
北大西洋鲱鱼（Clupea harengus）胚胎暴露于水中可容纳部分（WAF；溶解在水中的油）和化学增强水中可容纳部分（CEWAF；油分散在水中并添加了 Corexit 9500A）的中美洲南部（MESA）原油中。基于测试溶液的名义加载量（%v/v），CEWAF 的毒性比 WAF 大约高 100 倍。相比之下，以测量的油浓度表示的 WAF 和 CEWAF 毒性的比值近似为 1.0，表明 CEWAF 更高的毒性是由于暴露于化学分散的碳氢化合物的增加所致。在第二项实验中，与化学分散的重燃料油 7102（HFO 7102）相比，Corexit 9500A 和化学分散的 Nujol（一种无毒矿物油）对虹鳟鱼（Oncorhynchus mykiss）胚胎的慢性毒性进行了比较。分散剂本身是有毒的，但引起的毒性迹象与 HFO 7102 不同。在分散剂与油的比例为 1:20 时，Nujol 是无毒的，这表明分散剂被油隔离，没有达到毒性浓度。相比之下，相同名义负载的分散 HFO 7102 导致毒性随着浓度的增加而增加。这两个实验都表明，由于鱼类暴露于石油碳氢化合物的增加，而不是碳氢化合物毒性的变化，与机械混合产生的溶液相比，化学分散的油对鱼类胚胎的毒性更大。Nujol 对照区分了油和化学分散剂的毒性，这将是分散剂测试计划的一个实用补充。
