伊洛河(巩义段)排污口表层水体微塑料的赋存特征、分布与风险评价

Characteristics,Distribution and Risk Assessment of Microplastics in Surface Water of Sewage Outlet of Yiluo River(Gongyi Section)

作为一种新污染物,微塑料可通过排污口进入河流。通过采集伊洛河(巩义段)13个入河排污口表层水体的样品,采用显微镜观察、激光红外等方法,对其赋存特征、分布进行分析及定性,并进行风险评价。结果表明:①伊洛河(巩义段)排污口表层水体中微塑料平均丰度为(96.5±35.5)n/L,检出形态纤维状和透明色占比较高,粒径以<0.5 mm为主。②检出塑料种类分别为聚酰胺(PA)、聚乙烯(PE)、聚丙烯(PP)、聚苯乙烯(PS)、聚对苯二甲酸乙二醇酯(PET)和聚氯乙烯(PVC),其中,PET占比为16%~50%,PE占比为22%~48%,每个样点二者占比之和均超过50%。③污染负荷指数法评估该研究区段为低风险,而微塑料聚合物组成危害指数法和潜在生态风险指数法表明,有PVC检出的样点排污口表层水体风险会升高。研究显示,伊洛河(巩义段)排污口水体中微塑料引起的环境风险不仅与其丰度有关,还依赖于微塑料的种类,微塑料的潜在风险应引起重视。

Microplastics,as a new type of pollutant,can enter rivers through sewage outlets.Investigating microplastic pollution and its associated risks at the sewage outlets of the Yiluo River(Gongyi Section)lays the foundation for effective pollution mitigation strategies.In this study,sewage samples were collected from 13 sewage outlets along the Yiluo River(Gongyi Section),and their occurrence and distribution were qualitative analyzed.Microscopic observation and laser infrared techniques were employed for risk assessment.The results showed that the average content of microplastics at the Yiluo River sewage outlets was(96.5±35.5)n/L,mainly composed of fibrous transparent particles with sizes of<0.5 mm.Identified types included polyamide(PA),polyethylene(PE),polypropylene(PP),polystyrene(PS),polyethylene terephthalate(PET)and polyvinyl chloride(PVC).The proportion of PET ranged from 16% to 50%,while PE accounted for 22% to 48%.The combined percentage of the two exceeded 50%at each sample point.The pollution load index method was used to classify the study section as low risk.However,the microplastic polymer composition hazard index method and potential ecological risk index method highlighted elevated risks at the sites where PVC was detected.The environmental risk posed by microplastics at the outfalls was not only related to its abundance,but also depended on the type of microplastics,and therefore require focus on mitigating their potential ecological impact.