聚苯乙烯塑料粒子对河蚬的毒动力过程与毒理学效应

The tiny plastic pellets or fibers, which are called as microplastics, have become one of the most important issues of marine plastic pollution in recent years. More and more evidences have suggested that microplastic pollution is also very serious in freshwater envrionments such as lakes and rivers. However, there is a great lack of research of microplastics in freshwater organisms. In the present study, Asia clam (Corbicula fulminea) will be used as a model species in the laboratory and exposed to the fluorescently labeled microspheres of polystyrene in different sizes. By observing the fluorescent signal, we will study the selective absorption process of clam for microplastics, the transferring and accumulating characteristics of microplastics in the body of clam, and the way and time of elimination of microplstics. The dynamics of polystyrene microplastic in clams will be revealed. We will study the adverse effects of microplastics on the survival, growth, immunity and reproduction of clams. The toxic charactertics of microplastic in clams will be revealed at the level of tissue and cellar levels. We also will study the effects of microplastics on transcriptomes and key regulation genes of clams. The molecular mechanisms of microplastics in clams will be elucidated. The link will be bulit between the index at molecular level and that at tissue and cellar levels. The early molecular biomarkers will be chosen to indicate the toxic effects of microplastics on clams. The results of present study will increase the knowledge of toxic mechanisms of microplastics in freshwater organisms and provide scientific support for the risk assessment of microplastics to the ecosystem and human health.

近年来，尺寸极小的塑料颗粒或纤维（即微塑料）成为海洋塑料污染关注的重点，越来越多的证据表明湖泊和河流等淡水水域微塑料污染也十分严重。然而，微塑料对淡水生物影响的研究却非常缺乏。本项目拟以世界淡水水域广泛分布的河蚬为实验模型，选取不同大小的荧光聚苯乙烯塑料粒子，对河蚬进行室内暴露实验。通过荧光示踪的手段，观测河蚬对塑料粒子的吸收过程、在体内的转移和积累特征、以及排除途径和时间等，揭示塑料粒子对河蚬的毒动力学规律；通过研究塑料粒子对河蚬存活、生长、免疫和生殖等方面的影响，揭示塑料粒子对河蚬在组织和细胞以上水平上的毒性特征；通过研究塑料粒子对河蚬转录组和关键调控基因的影响，揭示塑料粒子对河蚬的分子毒理学特征；通过在分子与细胞及以上水平指标之间建立联系，筛选表征塑料粒子对河蚬毒性效应的早期分子生物学指标。本项目在增进人们对微塑料对淡水生物影响机制方面的认识，为塑料污染的生态和健康风险评估提供依据。

近年来，尺寸极小的塑料颗粒或纤维（即微塑料）成为海洋塑料污染关注的重点，越来越多的证据表明湖泊和河流等淡水水域微塑料污染也十分严重。然而，微塑料对淡水生物影响的研究却非常缺乏。本项目以世界淡水水域广泛分布的河蚬为实验模型, 调查长江中下游流域水体、沉积物和河蚬中微塑料的污染负荷。结果显示微塑料在淡水流域和河蚬体内普遍存在，水体中微塑料的丰度为0.5-3.1个每升水，沉积物中微塑料的丰度为15-160个每千克底泥，河蚬体内的微塑料丰度为0.3-4.9个每克组织。河蚬体内的微塑料丰度、颜色以及尺寸分布与水体尤其是沉积物中的微塑料污染显著相关（p<0.05）。我们提出将河蚬作为淡水体系微塑料污染的指示种。为了更好地模拟真实环境中的微塑料，我们制备了不同形状、材质以及尺寸的微塑料，并对河蚬进行暴露。根据前期的野外调查结果设置“环境相关”浓度为100和1000个每升水。对于不同的形状，河蚬摄取量最多的是粒子（0.5-10.2 个每克组织）；对于不同的材质，聚酯纤维摄取量最高（0.5-4.1个每克组织）；对于不同的尺寸， 100-250微米的聚酯纤维摄取最多（0.2-1.7个每克组织）。这些结果揭示了微塑料的物理化学特征例如形状、尺寸和材质会影响河蚬对微塑料的摄入。我们提出微塑料的室内暴露实验应使用“环境相关浓度和物理化学特性”，更进一步模拟真实环境中微塑料污染特征。