Aquatic sediments act as a storage for diverse mixtures of organic and inorganic contaminants. Nevertheless, most evaluations of contaminated sediments have been limited to the assessment of concentrations of target compounds and lethal effects on some test species. To identify the organic contaminants causing sub-lethal effects of contaminated sediment, this study combined chemical and biological (non)target analysis involving comprehensive two-dimensional gas chromatography coupled with a time-of-flight Mass Spectrometer (GCxGC/ToF-MS) analysis, embryonic malformation and high-throughput sequencing (RNA-seq) analysis on developing flounder. Polycyclic aromatic hydrocarbons were more abundant in the sediment extract of Yeongil Bay (SEY), while Jinhae Bay (SEJ) was contaminated with a large amount of unidentified chemicals. The unidentified chemicals of SEJ included branched alkanes, oxygenated cycloalkanes, heterogeneous hydrocarbons, and other unknown compounds. Percentage of pericardial edema was the highest in embryonic flounder exposed to SEY. Consistent with the morphogenesis results, the expression level of genes related to heart formation including the nkx2.5 and robo1 was greater in embryonic flounder exposed to SEY. In the analyses of differential gene expression profiles (cutoff P < 0.05), by RNA-seq, embryos exposed to SEJ showed changes related to cell differentiation, cell part morphogenesis, neurogenesis, and neuron development. Genes related to neurogenesis and positive regulation of molecular functions variated significantly in embryos exposed to SEY. These results demonstrated the advantages of combining target and non-target analysis to accurately evaluate the major chemical groups causing sediment toxicity. Therefore, this work provided a useful approach to tracking and revealing the causes of toxic effects and identifying potential toxic mechanisms.

水生沉积物充当各种有机和无机污染物混合物的储存库。然而，大多数对受污染沉积物的评估仅限于评估目标化合物的浓度和对某些测试物种的致命影响。为了识别造成受污染沉积物亚致死效应的有机污染物，本研究结合了化学和生物（非）目标分析，涉及全面的二维气相色谱与飞行时间质谱仪 (GCxGC/ToF-MS) 分析、发育中的比目鱼的胚胎畸形和高通量测序 (RNA-seq) 分析。英日湾（SEY）的沉积物提取物中多环芳烃含量较高，而镇海湾（SEJ）则受到大量不明化学物质的污染。 SEJ 的不明化学物质包括支链烷烃、含氧环烷烃、非均相碳氢化合物和其他未知化合物。暴露于 SEY 的胚胎牙鲆的心包水肿百分比最高。与形态发生结果一致，在暴露于SEY的鲽鱼胚胎中，与心脏形成相关的基因（包括nkx2.5和robo1）的表达水平较高。在通过 RNA-seq 分析差异基因表达谱（截止值P < 0.05 ）时，暴露于 SEJ 的胚胎显示出与细胞分化、细胞部分形态发生、神经发生和神经元发育相关的变化。在暴露于 SEY 的胚胎中，与神经发生和分子功能正向调节相关的基因发生显着变化。 这些结果证明了结合目标和非目标分析来准确评估引起沉积物毒性的主要化学基团的优势。因此，这项工作为跟踪和揭示毒性作用的原因以及识别潜在的毒性机制提供了一种有用的方法。