Barjhoux Iris, Clérandeau Christelle, Menach Karyn Le, Anschutz Pierre, Gonzalez Patrice, Budzinski Hélène, Morin Bénédicte, Baudrimont Magalie, Cachot Jérôme
Univ. Bordeaux, EPOC UMR CNRS 5805, allée Geoffroy Saint-Hilaire, 33615 Pessac Cedex, France.
Ecotoxicol Environ Saf. 2017 Aug;142:509-521. doi: 10.1016/j.ecoenv.2017.04.059. Epub 2017 May 4.
Sediment compartment is a long term sink for pollutants and a secondary source of contamination for aquatic species. The abiotic factors controlling the bioavailability and thus the toxicity of complex mixtures of pollutants accumulated in sediments are poorly documented. To highlight the different factors influencing sediment toxicity, we identified and analyzed the physico-chemical properties, micro-pollutant contents, and toxicity level of six contrasted sediments in the Lot-Garonne continuum. Sediment toxicity was evaluated using the recently described Japanese medaka (Oryzias latipes) embryo-larval assay with direct exposure to whole sediment (MELAc). Multiple toxicity endpoints including embryotoxicity, developmental defects and DNA damage were analyzed in exposed embryos. Chemical analyses revealed significant variations in the nature and contamination profile of sediments, mainly impacted by metallic trace elements and, unexpectedly, polycyclic aromatic hydrocarbons. Exposure to sediments induced different toxic impacts on medaka early life stages when compared with the reference site. Principal component analysis showed that the toxic responses following exposure to sediments from the Lot River and its tributary were associated with micro-pollutant contamination: biometric measurements, hatching success, genotoxicity, craniofacial deformities and yolk sac malabsorption were specifically correlated to metallic and organic contaminants. Conversely, the main biological responses following exposure to the Garonne River sediments were more likely related to their physico-chemical properties than to their contamination level. Time to hatch, cardiovascular injuries and spinal deformities were correlated to organic matter content, fine particles and dissolved oxygen levels. These results emphasize the necessity of combining physico-chemical analysis of sediment with toxicity assessment to accurately evaluate the environmental risks associated with sediment contamination.
沉积物隔室是污染物的长期汇，也是水生物种的二次污染来源。控制沉积物中积累的污染物复杂混合物的生物有效性进而毒性的非生物因素，文献记载较少。为了突出影响沉积物毒性的不同因素，我们识别并分析了洛特-加龙河连续区域内六种对比沉积物的物理化学性质、微污染物含量和毒性水平。使用最近描述的日本青鳉（Oryzias latipes）胚胎-幼体试验直接暴露于全沉积物（MELAc）来评估沉积物毒性。对暴露胚胎分析了包括胚胎毒性、发育缺陷和DNA损伤在内的多个毒性终点。化学分析表明，沉积物的性质和污染特征存在显著差异，主要受金属微量元素影响，出乎意料的是，还受多环芳烃影响。与参考地点相比，暴露于沉积物对青鳉早期生命阶段产生了不同的毒性影响。主成分分析表明，暴露于洛特河及其支流沉积物后的毒性反应与微污染物污染有关：生物测量、孵化成功率、遗传毒性、颅面畸形和卵黄囊吸收不良与金属和有机污染物具体相关。相反，暴露于加龙河沉积物后的主要生物学反应更可能与其物理化学性质有关，而不是与其污染水平有关。孵化时间、心血管损伤和脊柱畸形与有机物含量、细颗粒和溶解氧水平相关。这些结果强调了将沉积物的物理化学分析与毒性评估相结合以准确评估与沉积物污染相关的环境风险的必要性。
