莱州湾塑料微粒（microplastics）的污染现状及其毒性效应研究

The number of microplastics will increase inevitably in marine environment due to large amount of production and usage of plastics. The microplastic which might cause unpredictable environmental effect and ecological risk has attracted high attention from international societies. Presently, the research on the impacts of microplastic on marine organisms and ecosystem is still at the initial stage, and the molecular mechanism of its toxic effect and the toxicological risk evaluation is rarely reported. In this project, we aim to investigate the abundance and distribution of major microplastics in Laizhou Bay to clarify their pollution status. The acute and chronic toxicity of typical microplastics on representative marine organism of different life history stages is studied by traditional toxicological, transcriptomic and proteomic methods. Additionally, the molecular toxic mechanism of microplastic on marine organism is discussed. On this basis, the combined toxicity of typical microplastics and other pollutants is studied so as to evaluate the toxicity of microplastic systematically. The results of this project will contribute to evaluate the ecological risk of microplastic more accurately, and provide scientific basis for plastic pollution management and relevant policy making.

塑料的大量生产和使用不可避免地导致海洋环境中塑料微粒的数量日益增多。这些塑料微粒将给海洋带来难以预料的环境效应和生态风险，已引起国际社会的高度关注。目前，塑料微粒对海洋生物及生态系统影响的研究正处于起步阶段，从分子水平探讨其毒性效应及评估其毒性风险的研究鲜有报道。本项目选择我国北方典型海湾——莱州湾作为研究区域，通过检测该海湾主要塑料微粒的丰度和分布，初步查明塑料微粒的污染程度；采用常规毒理学、转录组学及蛋白质组学等技术，查明典型塑料微粒对莱州湾代表性海洋生物不同生活史阶段的急性和慢性毒性效应，并从分子水平上解析其毒性作用机制；在此基础上，进一步探索典型塑料微粒与环境中其它污染物的联合毒性效应，全面评估其毒性作用机制。研究结果不仅有助于更准确地评价海洋塑料微粒污染的生态风险，还可为我国塑料污染的管理和相关政策的制定提供科学依据。

近年来，微塑料已成为海洋环境科学研究的热点内容之一。本项目研究了我国莱州湾海域水体、沉积物和生物体的微塑料污染特征。结果发现，莱州湾微塑料污染普遍存在，分布较为均匀，秋季水体微塑料丰度高于夏季。与其他海域相比，莱州湾微塑料污染总体处于较高水平。水体和沉积物微塑料聚合物类型存在较大差异，表层水体低密度微塑料丰度显著高于沉积物。污染源主要包括河流输入、渔业生产和大气沉降。暴露实验结果表明，长牡蛎消化腺和鳃组织对微塑料（PE和PET）的富集量随时间的延长而增加，并且消化腺富集量大于鳃。微塑料暴露对长牡蛎摄食和呼吸影响不显著，对其抗氧化、能量代谢以及脂肪代谢酶活力影响较大。代谢组学分析表明，微塑料暴露影响长牡蛎消化腺的代谢过程，导致部分氨基酸和甘油磷脂水平上升。蛋白质组学分析表明，微塑料暴露影响代谢调节、信号转导和细胞骨架组织等生物学过程。高浓度微塑料暴露还会引起长牡蛎组织病理损伤。微塑料和苯并芘复合暴露导致长牡蛎胚胎畸形率和幼虫死亡率上升，增加苯并芘对长牡蛎肝胰腺的氧化损伤，导致脂质过氧化。可见，微塑料可以增强多环芳烃对长牡蛎的毒性效应。证据权重法评估结果表明，微塑料对长牡蛎消化腺的危害范围为“中度”至“严重”，而对长牡蛎鳃的危害范围为“无”至“严重”，并且低浓度组的危险指数低于高浓度组。以上研究结果可为我国近海微塑料生态风险评估、源头管控和相关政策制定提供科学依据。