Li Yuan, Wang Xuejiang, Wang Yuan, Sun Ying, Xia Siqing, Zhao Jianfu
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
Sci Total Environ. 2022 Aug 10;833:155251. doi: 10.1016/j.scitotenv.2022.155251. Epub 2022 Apr 14.
Few studies have mentioned the enrichment of heavy metal pollutants on microplastics derived from degradable plastics. This study investigated the adsorption behavior of Pb(II) onto biodegradable poly(butylene succinate) (PBS) microplastics during its biodegradation. The results indicated that Pb(II) adsorbed by biofilm-colonized biodegraded-PBS microplastics (B-PBS) was about 10-folds higher than that of virgin PBS (647.09 μg·g versus 64.13 μg·g) due to the biofilm colonization and the degradation of PBS. After removing the biofilm, the biodegraded PBS still had high Pb(II) adsorption capacity, which was attributed to the complexation of Pb(II) and the stably adhered extracellular polymeric substances (EPS). Pb(II) adsorption onto both virgin PBS and B-PBS was highly pH-dependent, its adsorption on virgin PBS was dominated by electrostatic interaction, while as for B-PBS, the adsorption mechanisms mainly involved the coordination/complexation of Pb(II) and the EPS components on the colonized biofilm, surface complexation, and electrostatic interaction. This study suggested that the enrichment of heavy metal pollutants onto the biodegradable microplastics may pose risks to the aquatic ecosystem.
很少有研究提及重金属污染物在可降解塑料衍生的微塑料上的富集情况。本研究调查了在生物降解过程中，Pb(II)在可生物降解的聚丁二酸丁二醇酯（PBS）微塑料上的吸附行为。结果表明，由于生物膜定殖和PBS的降解，被生物膜定殖的生物降解PBS微塑料（B-PBS）吸附的Pb(II)比原始PBS高约10倍（分别为647.09 μg·g和64.13 μg·g）。去除生物膜后，生物降解的PBS仍具有较高的Pb(II)吸附能力，这归因于Pb(II)与稳定附着的胞外聚合物（EPS）的络合作用。原始PBS和B-PBS对Pb(II)的吸附都高度依赖于pH值，原始PBS上的吸附主要由静电相互作用主导，而对于B-PBS，吸附机制主要涉及Pb(II)与定殖生物膜上的EPS成分的配位/络合、表面络合和静电相互作用。本研究表明，重金属污染物在可生物降解微塑料上的富集可能对水生生态系统构成风险。
