会仙岩溶湿地微塑料的时空分布特征及其影响因素

Spatial and Temporal Distribution Characteristics and Influencing Factors of Microplastics in Huixian Karst Wetland.

为探究淡水湿地系统的微塑料时空分布特征以及影响因素,分别在丰水期和枯水期从典型岩溶湿地会仙湿地流域范围内采集了10个地点的水体和沉积物样品。结果表明,会仙湿地丰水期微塑料丰度范围分别为5466.7~24333.3 n·m^(-3)(水体)和3380.0~14533.3 n·kg^(-1)(沉积物),枯水期分别为12713.3~34906.7 n·m^(-3)(水体)和11866.7~42486.7 n·kg^(-1)(沉积物),微塑料丰度在时空分布特征上呈显著差异(P<0.05)。会仙湿地微塑料的形状主要有纤维状、薄膜状、碎片状和颗粒,其中,水体中微塑料以纤维状为主,沉积物中微塑料以碎片状为主。丰水期和枯水期水体和沉积物中均以小粒径(0.45μm~0.5 mm)微塑料占优势,不同粒径微塑料丰度随粒径增大呈减少趋势。聚合物成分主要为聚对苯二甲酸乙二醇酯(PET)、聚苯乙烯(PS)、聚丙烯(PP)和聚乙烯(PE),水体中最主要的聚合物类型是PE,在沉积物中则是PET。就丰水期和枯水期对比来看,丰水期微塑料丰度显著低于枯水期,这是由于河流水位上涨造成的稀释效应。除此之外,枯水期小粒径(0.45μm~0.5 mm)微塑料占比和聚合物类型中PE占比更高。从空间分布来看,在旅游区、渔业和农业集中区以及村庄附近微塑料丰度高于其他地区,会仙湿地微塑料的主要来源包括农村生活污水排放、渔业养殖、农业生产和旅游业活动。

To investigate the spatiotemporal distribution characteristics and influencing factors of microplastics in freshwater wetland systems,water and sediment sampling were conducted at 10 locations within the Huixian wetland basin,a representative Karst wetland,during both wet and dry seasons.The findings revealed that the abundance of microplastics in the Huixian wetland ranged from 5466.7 to 24333.3 n·m^(-3)(water)and 3380.0 to 14533.3 n·kg^(-1)(sediment)during the wet season.In the dry season,the range was 12713.3 to 34906.7 n·m^(-3)(water)and 11866.7 to 42486.7 n·kg^(-1)(sediment).Significant spatial and temporal differences were observed in the distribution characteristics of microplastics abundance(P<0.05).The dominant shapes of microplastics in the Huixian wetland were fibers,films,fragments,and pellets.Fibers were primarily found in water,while fragments were more prevalent in sediments.Microplastics with small particle sizes(0.45μm to 0.5 mm)were predominant in both water and sediments during both wet and dry seasons.The abundance of microplastics decreased with the increasing of particle size.The identified polymer components were mainly polyethylene terephthalate(PET),polystyrene(PS),polypropylene(PP),and polyethylene(PE).PE was the predominant polymer type in water,while PET dominated in sediments.The abundance of microplastics in the wet season was significantly lower than that in the dry season,likely attributed to the dilution effect caused by rising water levels.Moreover,the dry season exhibited higher proportions of microplastics with small particle sizes(0.45μm to 0.5 mm)and a higher proportion of PE among the polymer types.In terms of spatial distribution,areas such as tourist sites,concentrated fishery and agricultural zones,and vicinity of villages displayed higher microplastics abundance compared to other areas.The main sources of microplastics in the Huixian wetland include rural domestic sewage discharge,fish farming,agricultural activities,and tourism.