纳米富勒烯在水生食物链传递过程中的迁移机制与毒性变化

Fullerene (C60) forms stable aqueous nanocrystal fullerene (nC60) after being released into aqueous environment and its adverse effects in aqueous environment are getting more and more attention. In this study, Scenedesmus obliquus is selected as producer, Daphnia magna is selected as primary consumer, and Carassius auratus gibelio is selected as secondary consumer. Those three creatures form a food chain of "water - Scenedemus obliquus - Daphnia magna - Carassius auratus gibelio" in aqueous environment. Then the research of nC60 in this aqueous food chain will focus on the process of absorption and distribution, changes in status, transfer efficiency, the balance of accumulation and depuration, and changes in toxic mechanism. From the individual in food chain to the whole food chain creatures, the contents of this study will be carried out in five main aspects: 1. absorption and status changes of nC60 in the intestine of secondary consumer Carassius auratus; 2.distribution and balance of nC60 in body of secondary consumer Carassius auratus; 3. trophic transfer process and efficiency of nC60 from Daphnia magna to Carassius auratus; 4. establishment of transfer equation for nC60 in the food chain of "water - Scenedesmus obliquus - Daphnia magna - Carassius auratus gibelio"; 5. transfer and changes in toxicity of nC60 in food chain. The expected results not only attribute scientific understanding in the transfer mechanism of nC60 in aqueous food chain, but also provide theoretical basis for further proposal and establishment of safety threshold for aqueous food.

富勒烯（C60）进入水体后会形成水稳晶体型纳米颗粒（nC60），其环境负效应越来越受到关注。本研究拟选择斜生栅藻作为生产者，大型溞作为初级消费者，异育银鲫幼鱼作为次级消费者，构成"水体－斜生栅藻－大型溞－异育银鲫"的水生食物链，研究揭示nC60在水生食物链中的吸收扩散过程、形态变化、迁移效率、累积自净规律及其毒性变化机制等。研究采用由个体到食物链的方式，内容主要包括nC60在次级消费者异育银鲫肠道的吸收过程及其形态变化、nC60在次级消费者异育银鲫体内的扩散与平衡过程、nC60在大型溞与异育银鲫间的迁移过程及迁移效率、nC60 在"水体－斜生栅藻－大型溞－异育银鲫"食物链中的迁移方程构建和nC60 在水生食物链的毒性迁移和变化机制等。研究成果不仅对于认识和揭示nC60在水生食物链中的迁移转化机制具有科学价值，而且可以为进一步提出和建立基于水产食品安全的水体nC60安全浓度阈值提供理论依据。

富勒烯（C60）进入水体后会形成水稳晶体型纳米颗粒(nC60),其环境负效应越来越受到公众的关注。本研究选择斜生栅藻作为初级生产者，大型溞为初级消费者，斑马鱼作为次级消费者，构成“水体-斜生栅藻-大型溞-斑马鱼”的水生食物链，研究揭示nC60在水生食物链中的摄入过程、形态变化、毒性作用及其作用机制。研究结果表明：nC60暴露给斜生栅藻21天后，光合作用的产物，如可溶性蛋白、糖原和脂类等含量均降低，这是由于在nC60的作用下，藻细胞的镁离子浓度降低，进而影响到细胞叶绿素a和叶绿素b的含量所致。纳米水稳型富勒烯(nC60)与 Zn2+和 Cr6+对大型溞具有联合毒性作用。将食源大型溞（用nC60暴露）喂食给斑马鱼后，不仅降低了斑马鱼的体重，而且还降低了20%的食物转化率（从大型溞到斑马鱼），进一步的研究表明nC60可以降低斑马鱼体内胰蛋白酶、脂肪酶和淀粉酶的活性，在活体和离体实验中，三种酶分别降低30, 29, 55% 和60, 90, 42%。此外纳米银对斜生栅藻的生物毒性主要是颗粒态饿纳米银及其释放的银离子共同作用的结果。本研究结果不仅对于认识和揭示nC60和纳米银等纳米颗粒在水生食物链中的迁移转化机制具有科学价值，而且可以为进一步提出和建立基于水产品安全的水体nC60安全浓度阈值提供理论依据。