长江口微塑料时空分布及风险评价

2017年春季、夏季在长江口附近海域进行采样，并对表层沉积物中微塑料的空间与时间分布规律进行了定性与定量的分析，利用污染负荷指数评价微塑料污染的风险程度.结果表明微塑料的浓度分布在季节变化上表现出明显的差异，在降水量丰富的夏季，微塑料的含量普遍更高；相同季节不同站点之间无明显的浓度分布差异，降水量对海洋微塑料的时空分布具有明显的影响.杭州湾海域在夏季期间微塑料浓度最高，为（39.33±14.34）particles/kg（DW）.微塑料的长度多在0.07~1.0mm之间，颜色丰富，形态主要为纤维状.傅里叶显微红外光谱仪检测出样品中含有的微塑料种类有聚乙烯、聚丙烯、聚氯乙烯、聚苯乙烯、聚酰胺，其中聚乙烯是主要的微塑料多聚物类型.运用污染负荷指数对微塑料的污染程度进行评价，长江口-杭州湾及其邻近海域的微塑料污染较轻.

Spatial-temporal distribution and pollution load of microplastics in the Changjiang Estuary

There has been a recent focus on microplastics (<5mm) because of their presence in different environmental media. The spatial and temporal distribution of microplastics in the surface sediments of the Changjiang Estuary were investigated in March and July 2017. Sampling was conducted at 17 stations covering the north passage and south passage of the Changjiang Estuary, East China Sea and Hangzhou bay. Among these sampling stations, the highest concentration of microplastics was (39.33±14.34) particles/kg (DW) in the Hangzhou bay in summer. There was no significant difference in spatial distribution of microplastics. The amount of precipitation was highly related with the abundance of microplastics, which showd higher concentrations in summer than in spring. The size, color, shape and composition of microplastics were classified. Attenuated total reflectance-Fourier transform infrared spectrometry showed that there were several types of microplastics existing in sediments, including polyethylene, polypropylene, polyvinyl chloride, polyamide, and polystyrene, among them, polyethylene was the main type. The method of pollution load index was used to assess the degree of microplastic pollution. Overall, the Changjiang Estuary-Hangzhou bay and its adjacent areas were less polluted by microplastics.