鄱阳湖主要入湖段典型底栖动物体内微塑料累积特征

以鄱阳湖-饶河和鄱阳湖-赣江中支两个主要入湖段典型底栖动物(河蚬、圆顶珠蚌、中国圆田螺)为对象,通过组织消解、滤膜过滤分离和显微镜检筛分微塑料(粒径<5mm),分析底栖动物体内微塑料的累积特征。结果表明:三种底栖动物体内均有微塑料淀积且主要淀积于消化道组织中,不同物种淀积丰度表现为河蚬>中国圆田螺>圆顶珠蚌;淀积的微塑料类型包括颗粒类、碎片类、薄膜类和纤维类,其中以纤维类为主;微塑料颜色主要有透明、蓝、红、紫;粒径以<1 mm的丰度最高,且随粒径增大丰度呈递减的趋势;空间尺度上,饶河入湖段底栖动物体内微塑料丰度高于赣江中支入湖段。本研究表明,鄱阳湖微塑料污染已造成底栖动物体内微塑料的累积,湖水产品的食用需要谨慎,但与国内外其他研究相比,本次研究区域的底栖动物处于中等微塑料污染。

Deposition characteristics of microplastics in benthic animals from the main estuaries of Poyang Lake

Microplastics are a kind of widespread environmental contaminants,with serious threat to aquatic environment.In this study,three benthic species(Corbicula fluminea,Unio douglasiae and Cipangopaludina cahayensis)were sampled from the estuary of Raohe River to Poyang Lake and the estuary of the middle tributary in lower Ganjiang River to Poyang Lake.The samples were screened by tissue digestion,and then filtered through the filter membrane.The membranes were dried and observed under metallographic microscope to identify plastic fragments.The abundance and types of microplastics in the benthic animals were analyzed.Microplastic deposition was found in all the three benthic species,particularly in their digestive tracts,with their deposition abundance descending as follows:C.fluminea>C.cahayensis>U.douglasiae.The microplastics deposited in the three benthic species can mainly be divided into four types,including particles,chips,films,and fibers,with fibers being the dominant type.The dominant colors of the microplastics were transparent,blue,red,and purple.The abundance of microplastics with particle size less than 1 mm was the highest.The microplastic abundance in the benthic animals decreased with increasing particle size.Spatially,the microplastic abundance of benthic species from the estuary of Raohe River to Poyang Lake was higher than that from the estuary of the middle tributary in lower Ganjiang River.It is concluded that the microplastic pollution in Poyang Lake has resulted in microplastic deposition in benthic species.More attention therefore should be paid on controlling the intake of aquatic products from the lake.In comparison with other studies,the microplastic pollution of benthic animals in this study is at the medium level.