东江河源段表层水体及鱼类肠道中的微塑料污染特征

Microplastic Pollution in Surface Waters and Fish Intestines in the Heyuan Section of Dongjiang River

统计并分析东江河源段表层水体及鱼类肠道中的微塑料污染现状,可丰富内陆水域尤其是珠江流域的微塑料数据,为进一步研究淡水水体的微塑料污染特征提供数据支撑。2019年6月采集东江河源段的表层水体及䱗(Hemicculter Leuciclus)、黄颡鱼(Pelteobagrus fulvidraco)、黄鳍刺鰕虎鱼(Acanthogobius flaviman)、鲤(Cyprinus carpio)、鲮(Cirrhinus molitorella)和子陵吻鰕虎鱼(Rhinogobius giurinus)的肠道作为试验材料,在体视显微镜下对表层水和鱼类肠道滤膜进行观察和记录,分析其微塑料污染特征。结果显示,6种鱼类的肠道中都发现了微塑料,丰度为57.3~2910.3个/kg;水体中微塑料丰度为366.67~1200个/m^(3)。表层水中65.93%微塑料为蓝色,以纤维为主,尺寸<2 mm的微塑料占比达88.95%;鱼体中尺寸<0.5 mm的微塑料占比41.41%,超过84.73%为透明和蓝色,主要以纤维和碎片为主。使用傅立叶变换红外光谱仪对微塑料样品进行成分鉴定,表层水中微塑料主要成分是聚苯乙烯,占比37.5%;6种鱼类肠道内的微塑料成分以聚酰胺为主,占比22.39%。东江河源段表层水体的微塑料污染水平较低,水质较好;不同鱼类中的微塑料污染水平存在差异,污染水平总体偏高,可能与食性和栖息水层相关。

In recent years,microplastics have been found in the marine environment and organisms,and concern about their harmful effects has increased.However,there are few studies on microplastic pollution in surface waters and organisms in inland waters,especially in the Pearl River basin.The Heyuan section of Dongjiang River within Heyuan City,Guangdong Province,in the middle and upper reaches of Dongjiang River,accounts for 39.03% of the Dongjiang River basin area and is an important part of the Pearl River water system.In this study,the surface water and the intestines of six common fishes(Hemicculter Leuciclus,Pelteobagrus fulvidraco,Acanthogobius flaviman,Cyprinus Carpio,Cirrhinus Molitorella,Rhinogobius Giurinus)in the Heyuan section were selected for research,and we characterized microplastic pollution.Microplastic type,size and color in surface water and intestines were recorded using a stereomicroscope.In June 2019,12 surface water samples from 4 sites(S1-S4)and 143 fish samples from 2 sites(Y1-Y2)were collected for microplastic analysis.Microplastics were found in the gut of all six fish species with abundances ranging from 57.3 to 2910.3 particles/kg,and the abundance of microplastics in the water column ranged from 366.67 to 1200 particles/m^(3).Microplastics with size<0.5 mm in the fish body accounted for 41.41% of the total microplastic particles,over 84.73% were transparent or blue,and consisted mainly of fibers and fragments.In the surface water,microplastics with size<2 mm accounted for 88.95%,and most microplastics(65.93%)were blue and mainly fibers.The type of microplastic polymers was identified using FTIR spectroscopy and results show that the microplastics were primarily composed of polystyrene(37.5%)in the surface water and polyamide(22.39%)in the intestines of fish.Overall,the microplastic pollution levels in the surface water at Heyuan section of the Dongjiang River were low and the water quality was good,while the microplastic pollution levels in fish were generally high and varied by species,likely related to feeding habitats and the water layer inhabited.Our study adds to the microplastic database in inland waters,especially in the Pearl River basin,and provides data to support further studies on microplastic pollution in freshwater bodies.