Occurrence And Distribution Characteristics Of Microplastics In Intertidal Sediments Of Fujian And Taiwan And Surface Water Of The Taiwan Strait

Coastal zone was an area with frequent human activities and an important area for aquaculture.It also was a transition area between land and ocean.Intertidal areas in coastal zones was extremely easy to pollute by microplastics caused by such as surface water,sewage discharge from human activities,offshore aquaculture,and coastal beach tourism.Intertidal areas across the Taiwan Straits were affected by frequent human activities,and microplastics pollution has become inevitable.There were differences in social development between Fujian and Taiwan,and the microplastics in the water in Taiwan Strait were obviously affected by river discharge and human activity discharge.This study selected intertidal areas across the Taiwan Straits and the surface seawaters of Taiwan Strait as the research objects to investigate the basic characteristics of microplastics.Then,we got the surrounding city’s GDP(one hundred million yuan),land area(square kilometers),per capita GDP(yuan),urban disposable income(yuan)and other related economic data,to analysis the distribution of the microplastics in intertidal sediments and the possible relationship between socio-economic.Based on the results of data analysis,the influence factors of the distribution and potential source of microplastics were explained.Combined with the distribution of microplastics in surface seawater of Taiwan Strait,the distribution and source of microplastics in Taiwan Strait also were discussed.The main research results were as follows:(1)In the intertidal sediments,the microplastics abundances were in the range of 28-208(mean 90)and 10-246(mean 69)items/kg(dry weight,the same below)along the Fujian(west)and Taiwan(east)coasts,respectively.The abundance of microplastics along the coast of Fujian was relatively higher than that of Taiwan,and was at a low level in the western Pacific coast area.This indicates that the abundance of microplastics in this area was generally low,which was related to the differences of human activities such as regional economic development,population,land use and so on.The chemical composition were determined by using FTIR,polyethylene,polypropylene,rayon,polystyrene,polyester were five common chemical compositions,and the Fujian coast was significantly more than Taiwan,which migh related to the differences in industrial structure and human activity intensity between Fujian and Taiwan.Black,white and transparent accounted for a large proportion,fragments,films,fibers,and granule were common shapes.(2)Clustering analysis was conducted on the color,shape and composition of microplastics in intertidal sediments along the coast of Fujian.The results were generally consistent with the clustering results of socio-economic indicators,which indirectly indicated that the distribution of microplastics was related to socio-economic development.Further analysis showed that the Pearson correlation coefficients between the abundance of microplastics and social and economic development indicators were generally positive,which indicated that with the further development of socioeconomic development,the pollution of microplastics may worsen.The Pearson correlation coefficients between the chemical composition of microplastics and the social and economic development indicators were generally less than 0.5,and the difference was obvious.Some microplastics components are significantly correlated with the social and economic development indicators,indicating that the distribution factors affecting the distribution of microplastics were more complex.(3)The regression analysis of the characteristic parameters of microplastics in the intertidal sediments along the coast of Fujian and the socio-economic development indicators showed that the urbanization level was negatively correlated with the foam,and positively correlated with the fiber.We made a fitting between population of the city and the abundance of microplastic.The results showed that within the confidence interval of 90%,the abundance of microplastics decreased with the increase of population.When the population reached a certain level(1.6118 million),the abundance of microplastics increased with the increase of population,indicating that there was a correlation between the abundance of microplastics and population.(4)The results of pumping samples in spring and summer in the Taiwan Strait showed that there were significant differences in the abundance and chemical composition of microplastics in the surface water of the Taiwan Strait in spring and summer.In spring,the abundance of microplastics was 10-104 items/m3(average 46 items/m3),and the chemical composition was mainly polyester,alkyd resin,polyethylene-polypropylene,cellophane,acrylic resin.In summer,the abundance of microplastics ranged from 24-128 items/m3(average 58 items/m3),with rayon,alkyd resins and polyester being the main chemical composition.The abundance of microplastics in the surface water of the Taiwan Strait in spring was slightly lower than that in summer,which may be related to the circulation of the surface water in the Taiwan Strait.In this study,the influencing factors of microplastics distributed in the coastal areas of Fujian and Taiwan where human activities were frequent were explored.The results provided basic data and theoretical support for the ecological risk assessment of microplastic pollution in the Taiwan Strait.It could provide a scientific basis for the research and treatment of microplastics in Fujian and Taiwan,which was of great significance to the maintenance of the overall health and sustainable development of the ecological environment on both sides of the Taiwan Straits.Meanwhile,it also provided a scientific support for the formulation of plastic control policies and industrial structural adjustment in Fujian and Taiwan.