汜水河(荥阳段)入河排污口水体微塑料赋存特征及风险评估

Occurrence Characteristic and Risk Assessment of Microplastics in Sishui River(Xingyang Section)

城市河流是微塑料的主要接纳者与传输者.探明城市河流微塑料污染状况及其环境风险,可为进一步控制微塑料污染提供依据.以黄河支流汜水河作为研究对象,采集汜水河(荥阳段)9个排污口的污水样品,通过显微镜对微塑料尺寸、形状及颜色等赋存形态进行分析,发现微塑料在排污口水体中多以透明状的纤维和碎片形式存在,且500μm以下占比较高;进一步采用激光红外成像仪对微塑料种类进行鉴定,发现PET和PE聚合物是主要的微塑料种类,且二者显著相关,表明它们在来源上有相似性.环境风险评价结果表明,微塑料种类是影响评价结果的主要因素,有PVC检出的6个排污口水体环境风险值较高,而污染负荷指数评价结果显示整个研究区段处于低风险水平.

Urban rivers are the main receptors and transporters of microplastic pollution.Understanding the occurrence and environmental risk of microplastics in urban rivers can provide theoretical basis for further control of microplastic pollution.The Sishui River,a tributary of the Yellow River,was selected as the research object.A total of nine water samples were collected from sewage outlets of the Sishui River(Xingyang section).The microplastics in the collected samples were characterized by their sizes,shapes,and colors using a microscope.It was found that microplastics were mostly in the form of transparent fibers and fragments in the water body of sewage outlets,of which the size below 500μm was relatively high.In addition,PET and PE polymers were identified as the main types using a laser infrared imager.The correlation analysis showed that there was a significant correlation between the PET and PE,indicating that they were similar in origin.The results of the environmental risk assessment showed that the type of microplastics was the main factor affecting the assessment results,whereas the risk values of six sewage samples containing PVC were high.However,the value of pollution load index revealed a low risk level of pollutants in the study area.