College of Life Science, Jiangxi Provincial Key Laboratory of Protection and Utilization of Subtropical Plant Resources, Jiangxi Normal University, Nanchang, 330022, China; Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang, 330022, China.
College of Life Science, Jiangxi Provincial Key Laboratory of Protection and Utilization of Subtropical Plant Resources, Jiangxi Normal University, Nanchang, 330022, China.
Chemosphere. 2022 Dec;309(Pt 1):136547. doi: 10.1016/j.chemosphere.2022.136547. Epub 2022 Sep 24.
Microplastics (MPs) are widely detected in wetlands as emerging pollutants of global concern. Co-occurrence of MPs and trace metals in wetlands is common and the vector effects of MPs on other environmental pollutants have been increasingly reported. However, the interaction of different MPs and trace metals under environmentally realistic conditions is not well understood. Here, we investigated the adsorption capacity of MPs for metals under simulated conditions of Poyang Lake wetlands in Jiang Xi, China, a Ramsar site of international importance for conservation and sustainable use. ICP-MS was used to quantify the amount of adsorbed metals onto different types of MPs. SEM-EDS and micro-FTIR were used to examine the morphological and chemical characteristics of MPs before and after metal adsorption. The influence of internal (polymer types and particle sizes of MPs) and external factors (water pH values, organic matters, ion strength, and sediment) on metal adsorption was systematically investigated. Metal adsorption equilibrium was most achieved at 72 h. The adsorption capacity of MP types to metal ions tended to decrease as PP > PE > PS, and the amount of adsorbed metals decreased as Cu > Pb > Cd. The amount of adsorbed metals generally decreased with the increase of particle size of MPs. With the increase of water pH and K strength, the adsorption of metals by MPs showed an increasing and then decreasing trend; the adsorption capacity of MPs increased with the increase of fulvic acid. Under the simulated sedimentary conditions, the adsorption of different metals by MPs also tended to be Cu > Pb > Cd, which was mainly determined by metal concentrations in the sediments collected in situ. The results of this study improve our understanding of metal-MP interaction under simulated environmental conditions, shedding new light on the environmental behavior of MPs and metals in wetlands.
微塑料（MPs）作为新兴的全球性关注的污染物，在湿地中广泛检出。湿地中 MPs 和痕量金属的共同存在很常见，而且 MPs 对其他环境污染物的载体效应也被越来越多地报道。然而，在实际环境条件下，不同 MPs 和痕量金属之间的相互作用还不太清楚。在这里，我们研究了在模拟的江西鄱阳湖湿地条件下 MPs 对金属的吸附能力，鄱阳湖是具有国际重要保护和可持续利用意义的拉姆萨尔湿地。我们使用 ICP-MS 来量化不同类型 MPs 上吸附的金属量。SEM-EDS 和微傅里叶变换红外光谱（micro-FTIR）用于检测金属吸附前后 MPs 的形态和化学特征。系统研究了内部因素（聚合物类型和 MPs 粒径）和外部因素（水的 pH 值、有机物、离子强度和沉积物）对金属吸附的影响。在 72 小时达到金属吸附平衡。MP 类型对金属离子的吸附能力趋于随着 PP>PE>PS 而降低，而吸附的金属量随着 Cu>Pb>Cd 而降低。随着 MPs 粒径的增大，吸附的金属量通常会减少。随着水 pH 值和离子强度的增加， MPs 对金属的吸附表现出先增加后减少的趋势；随着腐殖酸的增加， MPs 的吸附量增加。在模拟的沉积条件下， MPs 对不同金属的吸附也趋于 Cu>Pb>Cd，这主要取决于原位采集沉积物中的金属浓度。本研究的结果提高了我们对模拟环境条件下金属-MP 相互作用的理解，为湿地中 MPs 和金属的环境行为提供了新的认识。
