水体及沉积物微塑料污染对近海养殖海区的生态风险

Study on the ecological risk of water and sediment microplastic pollution on offshore marine aquaculture areas

微塑料在全球海洋水体及沉积物中广泛存在,然而关于近海养殖海区的微塑料污染特征鲜有报道,本研究调查了中国近海养殖海区茅尾海水体和沉积物中微塑料的分布特征并初步对其微塑料污染进行风险评估.结果表明,茅尾海区域广泛分布着微塑料,茅尾海水体中微塑料的平均丰度为(2.01±1.23)n·m^(−3),泡沫(60.1%)是主要的类型.沉积物中的微塑料平均丰度为(22.4±19.6)n·kg^(−1),薄片(50%-100%)在采样点中占主要部分.茅尾海水体、沉积物中的微塑料粒径都以1-5 mm为主(33.3%-100%),水体和沉积物中的微塑料主要来自钦江的输入、旅游活动以及海水养殖活动.通过风险评估模型初步得出,茅尾海区域微塑料的污染水平属于中等偏低水平,水体中微塑料整体污染风险等级显著高于沉积物,生态风险等级分别属于Ⅲ级(较高风险)和Ⅱ级(较低风险).风险指数最高的点位于茅尾海入海河流钦江入海处,达到了Ⅳ级(高风险),各沉积物采样点的风险等级主要集中在Ⅰ—Ⅱ级,属于较低风险.危害评分高的聚合物聚丙烯腈(Polyacrylonitrile,PAN)是水体中微塑料污染风险的重要来源.

Microplastics are widely present in marine waters and sediments worldwide,However,the pollution characteristics of microplastics in offshore aquaculture areas are rarely reported.In this study,the distribution characteristics of microplastics in seawater and sediments in offshore aquaculture areas of Maowei Sea were investigated.Furthermore,a preliminary risk assessment of microplastic pollution was conducted.The results showed that microplastics were widely distributed in the Maowei Sea.The average abundance of microplastics in Maowei Sea was(2.01±1.23)n·m^(−3).Foam(60.1%)was the dominant type.The average abundance of microplastics in sediments was(22.4±19.6)n·kg^(−1).Sheet(50%-100%)were the main part in the sampling sites.The particle size of microplastics in seawater and sediment of Maowei Sea is 1-5 mm(33.3%-100%).It was found that the microplastics in the seawater and sediments were mainly from the input of Qinjiang River,tourism activities,and mariculture activities.According to the risk assessment model,the pollution level of microplastics in Maowei Sea is medium to low level.The overall pollution risk level of microplastics in water was significantly higher than that in sediments,belonging to gradeⅢ(slightly higher risk)and Ⅱ(slightly low risk)respectively.The highest risk index is located in the Maowei Sea into the sea river Qinjiang River into the sea,reachedⅣlevel(high risk),Risk level of each sediment sampling point are mainly concentrated in Ⅰ—Ⅱlevel,belongs to low risk.Polymer polyacrylonitrile(PAN)with high hazard score is an important source of microplastic pollution risk in water.