University of Le Havre, Laboratory of Ecotoxicology (LEMA) EA3222, 25 rue Philippe Lebon, 76058 Le Havre Cedex, France.
Aquat Toxicol. 2011 Oct;105(3-4):235-45. doi: 10.1016/j.aquatox.2011.06.011. Epub 2011 Jun 15.
Despite their low water solubility, hydrophobic pollutants are widespread in the aquatic environment and could represent a threat for living organisms. EU regulations on chemicals require accurate and reliable data on chemical toxicity. Current normalised fish toxicity assays, in particular those advocated by OECD guidelines, do not allow reliable toxicity assessment of hydrophobic compounds due to their low water solubility. In order to accurately evaluate the toxicity of this kind of compounds, a new spiked sediment assay using embryos of the Japanese medaka was developed. It consists of directly exposing fertilised eggs, during their entire embryonic development, onto the reference sediment spiked with the test compound. A large set of lethal or sublethal effects in embryos and newly hatched larvae, including non-invasive endpoints is analysed in order to maximise the sensitivity of the test. The approach was validated using four model pollutants with different modes of action: DMBA, PCB126, PCB153 and 4-nonylphenol (NP). All compounds, except PCB153, induced a dose-dependent increase in toxic effects. In fact, lethal effects only occurred at the highest tested concentration. In contrast, sub-lethal effects including skeletal deformations, cardiac activity modulation, body length reduction and hatching delay were observed at low to moderate concentrations of DMBA and PCB126. NP induced subtle effects in embryos, altering cardiac activity and hatching success but only at high concentrations. Although a few more improvements would make it a fully standardised assay, this spiked sediment assay using medaka embryos proves to be sensitive enough to measure hydrophobic chemical toxicity using an environmentally realistic mode of exposure.
尽管疏水性污染物的水溶性较低，但它们在水生环境中广泛存在，可能对生物构成威胁。欧盟关于化学品的法规要求对化学品毒性进行准确和可靠的数据评估。目前的标准化鱼类毒性测试，特别是经合组织指南所倡导的那些测试，由于疏水性化合物的低水溶性，无法对其进行可靠的毒性评估。为了准确评估此类化合物的毒性，开发了一种新的使用日本青鳉胚胎的添加沉积物测定法。它包括在胚胎整个发育过程中直接将受精的卵子暴露在添加了测试化合物的参考沉积物上。分析了大量胚胎和刚孵化的幼体的致死或亚致死效应，包括非侵入性终点，以最大程度地提高测试的灵敏度。该方法使用四种具有不同作用模式的模型污染物进行了验证：DMBA、PCB126、PCB153 和 4-壬基酚（NP）。除 PCB153 外，所有化合物都导致毒性效应呈剂量依赖性增加。实际上，仅在测试的最高浓度下才会发生致死效应。相比之下，在 DMBA 和 PCB126 的低至中等浓度下，亚致死效应，包括骨骼畸形、心脏活动调节、体长减小和孵化延迟，都观察到了。NP 仅在高浓度下对胚胎产生轻微影响，改变心脏活动和孵化成功率。尽管还需要进行一些改进才能使其成为完全标准化的测定法，但使用青鳉胚胎的这种添加沉积物测定法已经足够灵敏，可以使用具有实际环境暴露模式来测量疏水性化学毒性。
