海洋酸化条件下重金属和金属纳米颗粒的环境行为及其对海洋生物的影响

Environmental behaviors and toxicity of heavy metals and metallic nanoparticles to marine organisms under ocean acidification

工业革命以来,海洋吸收人类排放的CO_2,导致地球表层海水碳酸盐浓度和pH持续下降,使得全球海洋出现酸化现象.海洋酸化(ocean acidification,OA)除直接威胁海洋生态系统的稳定外,还通过改变海洋污染物的环境行为间接改变其对海洋生物的毒性效应.本文以重金属和金属纳米颗粒(metallic nanoparticles,MNPs)等环境污染物作为主要的研究对象,通过对OA的成因进行深入分析,重点研究OA改变重金属的存在形态和影响金属纳米颗粒的溶解、悬浮、迁移等一系列过程的主要机理,探明这些重金属和MNPs的关键环境过程的改变对海洋生物个体的影响,并对其造成的毒性差异进行了重点分析.最后对OA与共存污染物毒性效应进一步需开展的研究工作进行了重点展望.

Since industrial revolution, anthropogenic carbon dioxides releasing into the atmosphere are absorbed by the global oceans, which leads to measurable decrease of surface seawater pH and carbonate ion concentration （[CO32-]）, thus causing the acidification of global ocean. Besides direct threatening the stability of marine ecosystems, ocean acidification （OA） could also change the environmental processes of marine pollutants, thus indirectly influencing their toxicity to marine organisms. By selecting heavy metals and metallic nanoparticles （MNPs） as the model marine pollutants, this review deeply summarizes the dominant mechanisms on species changes of heavy metals, and the dissolution, dispersion and transport of MNPs based on the causes of OA. The effects of OA-induced environmental process alteration on the toxicity of heavy metal and MNPs to marine organisms at different levels are explored. The differences among the observed toxicological data are analyzed. Finally, the key research challenges and future directions on the toxicity of OA and coexisting pollutants are provided.