南渡江入海河口水体中微塑料污染特征及风险评估

Pollution characteristics and risk assessment of microplastics in estuary water of Nandu River

南渡江入海河口作为海南河流和海洋的主要过渡区之一,其微塑料污染特征当前仍未被掌握。以南渡江入海河口为研究对象,以河口为中心扇形布设9个采样站位进行微塑料监测,结果显示,微塑料的主要成分为聚乙烯(28.7%)和聚丙烯(27.4%);以粒径<2.0 mm居多(58.7%);平均丰度为0.40个/m^(3),与国内外其他河口、海域同类研究结果相比处于中低水平。从空间分布看,离河口越近,微塑料的平均丰度越高,本研究区域微塑料的污染状况既受到河流输入影响,也受到外源输入影响。运用污染负荷指数和聚合物风险指数对微塑料的污染程度进行风险评估,微塑料污染负荷处于低风险水平(Ⅰ级),聚合物危害处于中高风险水平(Ⅳ级)。

As one of the major transition areas of the river basin and the ocean in Hainan,the characteristics of microplastic pollution in the estuary of Nandu River are still unknown.Taking the estuary of Nandu River as the research object,9 sampling sites were arranged in a fan shape centered on the estuary to monitor microplastics.The results showed that the main components of microplastics were polyethylene(28.7%)and polypropylene(27.4%).Microplastics with a particle size of less than 2.0 mm comprised a higher proportion(58.7%)of the total.The average abundance of microplastics was 0.40 particles/m^(3),which was at a medium-low level compared with similar research results in other estuaries and sea areas at home and abroad.From the spatial distribution,the average abundance of microplastics was higher in the area closer to estuarine.The pollution status of microplastics in this study area was influenced by both river inputs and external inputs.The pollution load index and polymer hazard index were used to evaluate the pollution degree of microplastics.The pollution load of microplastics was at the low risk level(Ⅰ),and the hazard of polymer was at the medium-high risk level(Ⅳ).