海洋青鳉胚胎不同发育阶段对120#燃料油毒性敏感性的比较

本研究考查了120#燃料油分散液（WAFs）对海洋青鳉（Oryzias melastigma）胚胎的毒性效应，测试其各发育阶段对WAFs的敏感性。将6 hpf（受精后小时数）、18 hpf和30 hpf的海洋青鳉胚胎分别暴露于不同浓度的WAFs中，并于暴露之后的12、24、48、72、96 h进行观察、记录并计算胚胎的蓝囊综合症（blue sac disease，简称BSD）指数、孵化率、心率以及半数致死浓度LC₅₀值等指标。结果表明，WAFs暴露可以对海洋青鳉胚胎发育产生明显的毒性影响，包括发育畸形、孵化率和心率下降、死亡率上升等现象，并伴随着明显的时间-剂量效应。各项指标对于WAFs暴露的敏感性各不相同，以BSD指数和孵化率变化更为明显。胚胎对于120#燃料油毒性的敏感性随着发育呈现逐渐下降的趋势，随着暴露起点的延后，毒性影响逐渐减小。但是，WAFs对海洋青鳉胚胎心率的影响主要作用于心脏发育阶段。

Comparison of sensitivity of marine medaka (Oryzias melastigma) embryo on different developmental stages to 120# fuel oil

In this paper, the toxic effects of 120# fuel oil water accommodated fractions (WAFs) on marine medaka (Oryzias melastigma) embryo were studied, with comparison of the sensitivities of embryos on different developmental stages.The marine medaka embryos of 6, 18 and 30 hpf (hour post-fertilization) were exposed to different concentrations of WAFs.The responses of embryos were observed and recorded at different time (12, 24, 48, 72 and 96 h after exposure), and the blue sac disease (BSD) index, hatching rate, heart rate and LC₅₀ were calculated separately.The results showed that WAFs exposure could cause obvious toxic effects, including malformation, decrease in hatching rate and heart rate, and increase in mortality, with significant time-dose effect relationships.The developmental endpoints showed a varying extent of sensitivity to WAFs among which the changes of BSD index and hatching rate were more significant.The sensitivity of embryos to 120# fuel oil gradually decreased with the development.The toxicity gradually decreased with the delay of the starting point of exposure.But the WAFs affected the heart rate mainly in the stage of cardiac development.