可生物降解聚乳酸塑料产生二次微塑料的行为特征  

The behavior characteristics of secondary microplastics from biodegradable polylactic acid

作　　者：肖娜 王艳华 刘锐涵 邵天杰 刘英楠 王韶 XIAO Na;WANG Yanhua;LIU Ruihan;SHAO Tianjie;LIU Yingnan;WANG Shao(School of Geography and Tourism,Shaanxi Normal University,Xi’an,710119,China;Shaanxi Hengxin Testing Co.,Ltd.,Xi’an,710119,China)

机构地区：[1]陕西师范大学地理科学与旅游学院,西安710119 [2]陕西恒信检测有限公司,西安710119

出　　处：《环境化学》2025年第1期309-321,共13页Environmental Chemistry

基　　金：国家自然科学基金(42277207,42342015);国家重点研发计划(2020YFC1808304);西安市科技局“科学家+工程师”团队建设项目(23KGDW0008-2023);咸阳市重点研发计划(2022ZDYF046);大学生创新创业项目创新计划(202310718088)资助.

摘　　要：近年来,塑料污染问题日趋严重.丢弃于环境中的塑料,在物理、化学、生物等作用下可释放微塑料(microplastics,MPs),对环境造成极大危害.目前,世界各地的多种环境介质中都检测到了MPs的存在,包括水体、大气、土壤、沉积物、空气等,且不同地区MPs污染差异较大.MPs的相关研究已然成为当前研究的热点,但目前的研究大多集中于探究不可降解MPs.因此,本文以可生物降解塑料聚乳酸(polylactic acid,PLA)为研究对象,探究PLA塑料的主要纺织产品(无纺布:常用于纸尿裤、卫生巾的制作)和包装产品(塑料袋和吸管)在环境中产生二次MPs的行为特征.通过模拟环境中的机械应力和光老化,明晰可生物降解塑料释放二次MPs的情况.研究发现,水环境中PLA商品静置24 h后可产生大量二次MPs(154颗粒/0.1 g—38801颗粒/0.1 g).机械应力、光照使PLA在环境中脱落更多的二次MPs,且随着光照的延长,所有PLA商品脱落的二次MPs逐渐增加.而机械应力和光照的共同作用,为二次MPs的产生提供了更多的可能性.PLA塑料商品虽在环境中可能有着更快的降解速率,但其在环境中产生二次MPs的速度快、数量多,可能有着更大的生态风险.研究结果将为深入理解可生物降解塑料PLA在环境中的风险提供理论依据和数据基础.In recent years,plastic pollution has become an increasingly serious problem.Plastics discarded in the environment released microplastics(MPs)under physical,chemical and biological effects,which caused great harm to the environment.MPs were detected in various environmental media around the world,including water,atmosphere,soil,sediment,air,etc.,and the pollution of MPs varied greatly from region to region.Research related to MPs became a hot topic,but most of the current studies focused on exploring non-degradable MPs.Therefore,this paper selected biodegradable plastic polylactic acid(PLA)as the research object to explore the behavioral characteristics of secondary MPs produced by the main textile products(non-woven fabrics:commonly used in the production of diapers and sanitary napkins)and packaging products(plastic bags and straws)of PLA plastic in the environment.By simulating mechanical stress and photoaging in the environment,the release of secondary MPs from biodegradable plastics was clarified.In aqueous environment,PLA commodities produced a large number of secondary MPs after 24 h of resting(154 n/0.1 g-38801 n/0.1 g),while mechanical stress and light made PLA shed more secondary MPs,and the secondary MPs shed by PLA commodities gradually increased with the extension of light time.The combined effect of mechanical stress and photoaging provided more possibilities for the generation of secondary MPs.Although PLA plastic commodities may have faster degradation rate in the environment,they may have greater ecological risk because of the rapid and large number of secondary MPs generated in the environment.The study would provide a theoretical foundation and data basis for further understanding of PLA risks in the environment.

关 键 词：可生物降解塑料 聚乳酸 二次微塑料 机械应力 光老化 

分 类 号：X-1[环境科学与工程] O6[理学—化学]