天津近岸海域微塑料污染现状分析

Current status of microplastics pollution in tianjin coastal waters

微塑料(microplastics,MPs)已成为继气候变化、臭氧问题、海洋酸化之后新的全球重大环境问题,为揭示天津近岸海域微塑料分布规律和影响因素,利用表层现场采样、密度悬浮法分离、光学显微镜相结合的方法,研究了天津开阔海域的3个断面微塑料的丰度分布,分析了微塑料的粒径范围、形状类型和化学成分.结果表明,所监测开阔海域的3个断面中,海水样品微塑料丰度在210—1170个·m-3之间,均值为612个·m-3;微塑料类型包括细长形的纤维、不规则状的碎片和薄膜,纤维和碎片占到绝大多数,分别占到52.1%和46.8%;而检出微塑料颗粒粒径同大多数研究相同,粒径越小,含量越多,其中55.3%的微塑料颗粒粒径是小于0.5 mm;通过Mphunter软件分析出表层海水中微塑料的颜色以深色系(如:蓝色、黑色、红色)居多,少数有黄色、绿色、白色;利用Bio-Rad Knowltall光谱分析出海水中微塑料主要成分有PP-PE(聚丙烯-聚乙烯)、ABS(苯乙烯-丁二烯-丙烯共聚物)、CE(纤维素塑料)、EP(环氧树脂)、PA(聚酰胺)、PE(聚乙烯)、PET(聚对苯二甲酸乙酸脂)、PP(聚丙烯)、PVC(聚氯乙烯)9种塑料类型,含量由高到低依次为:PET>PP-PE>EP>CE>ABS>PE>PA>PVC>PP.结果分析表明,天津近岸海域微塑料污染受到海洋产业发展的影响,如海洋渔业、港口运输等,同时由于天津属于工业化城市,人口密度也较大,因此海洋微塑料污染也受到陆源污水排放的影响.

Microplastics(MPs)have become a global concern as well as climate change,ozone depletion and ocean acidification.In order to reveal the distribution characteristics and influence factors of MPs in Tianjin coastal waters,the distribution of MPs in three sections of Tianjin offshore area was studied by using surface sampling,density suspension separation and optical microscopy.The size,shape and chemical composition of MPs were further analyzed.Our results showed that the abundance of MPs in the seawater samples were ranging from 210 to 1170 particles·m-3 with a mean of 612 particles·m-3 in the three sections of the offshore area.Three shape types of MPs were present in the seawater samples,including slender fibers,irregular fragments and thin films.Fibers and fragments were the predominant forms,which accounted for 52.1%and 46.8%,respectively.The particle size of the detected MPs was consistent with those reported by previous studies.The smaller the particle size,the higher the content.55.3%MPs had the particle size of less than 0.5 mm.According to the microscopy analysis result,most of MPs in surface seawater samples showed a deep color(such as blue,black and red),and a few MPs showed colors of yellow,green and white.The main chemical components of MPs were analyzed by using infrared microscopy.Nine components were detected,including PP-PE(polypropylene-polyethylene),ABS(styrene-butadiene-acrylic copolymer),CE(cellulose plastic),EP(epoxy resin),PA(polyamide),PE(polyethylene),PET(polyterephthalic acid acetate),PP(polypropylene),and PVC(polyvinyl chloride),with an order of PET>PP-PE>EP>CE>ABS>PE>PA>PVC>PP.Our results demonstrated that the MPs pollution in the Tianjin offshore area was affected by the development of marine industries,such as marine fishery,port transportation,etc.In addition,the MPs pollution in the ocean was also affected by land-based sewage discharge due to the fact that Tianjin was an industrialized city with a large population density.