双台子河与大辽河表层水体微塑料特征与分布研究

Characteristics and Distribution of Microplastics in Surface Water from Shuangtaizi River and Daliao River

微塑料是全球新兴环境热点问题之一。据估算,80%的海洋微塑料来于陆源输入,而河流被认为是陆源微塑料输入海洋的主要路径之一。为揭示辽河流域水体微塑料污染特征、空间分布及其对渤海微塑料污染的潜在贡献,本文基于密度分离原理并利用傅里叶变换红外光谱方法,研究了双台子河与大辽河下游至入海口(盘锦段)河道表层水体微塑料丰度、材质组成、形态特征与粒径分布特征。结果显示:从材质上分析,2条河流共检出了17种高分子聚合物,其中以聚乙烯占比最高,分别占双台子河和大辽河表层微塑料总量的38%和32%;从形态上分析,碎片微塑料(533.08~674.25μm)和纤维微塑料(1054.87~1450.76μm)分别占2条河流检出微塑料总量的80%以上,颗粒微塑料(100.26~241.3μm)占比则低于10%,并且没有检出形状规则的塑料微珠;从丰度上分析,双台子河((4.52±0.76)个·L^(-1))与大辽河((4.74±0.67)个·L^(-1))表层水体微塑料丰度之间无显著差异(P>0.05),并且各点之间也没有明显的变化趋势(P>0.05)。以上研究结果表明,双台子河与大辽河表层水体微塑料污染特征相似,这为开展渤海微塑料溯源和风险管理提供了直接依据。

Microplastic is one of global environmental issues in recent years.It is estimated that more than 80%of marine microplastics are discharged from land-sources,and river is regarded as the main pathway of microplastics from land reaching oceans.In order to understand the characteristic and distribution of microplastics in rivers flushing into Bohai Sea in Liaohe Basin,the present study investigated the abundance,polymer composition,morphological characteristic,and particle size of microplastics in surface water sampled from the downstream of Shuangtaizi River and Daliao River(Panjin district)to the estuaries.Firstly,the microplastics were isolated from water samples based on the principle of density isolation,and then the polymer of microplastics were identified using Fourier Transform Infrared Spectroscopy(FTIR).Finally,the results showed that totally 17 polymers were identified and confirmed in all samples from the two rivers,of which polyethylene(PE)dominated in these microplastics and accounted for 38%in Shuangtaizi River and 32%in Daliao River,respectively.Among these microplastics detected in water samples,more than 80%were fragments(533.08~674.25μm)and fibers(1054.87~1450.76μm),while pellets(100.26~241.31μm)accounted for less than 10%.The microplastics with regular shape was not detected in all samples.Importantly,the abundance of microplastics did not show significant difference among samples from Shuangtaizi River((4.52±0.76)items·L^(-1))and Daliao River((4.74±0.67)items·L^(-1))(P>0.05).There was also no obvious change trend of microplastic levels among sites in the two rivers(P>0.05).The present results indicated that the profile and spatial distribution of microplastics in Shuangtaizi River were similar to those in Daliao River,which provided a direct evidence for the pollution control and risk management of microplastics in Bohai Sea in future.