Microplastics in Surface Waters and Floodplain Sediments of the Dagu River in the Jiaodong Peninsula,China

To understand the pollution characteristics and distributions of microplastics in the Dagu River,an important inland river that flows to Jiaozhou Bay,the abundance,particle size,shape,color,and polymer type of microplastics in the surface waters and floodplain sediments were investigated.The results showed that the abundance of microplastics in the surface waters varied between 0.68 and 3.96 items L^(−1).The abundance of microplastics in the floodplain sediments varied between 115.5 and 495 items kg^(−1).The distribution of microplastics in the river has obvious characteristics:1)The abundance of microplastics downstream was significantly higher than that upstream.2)The abundance of microplastics decreased significantly in the estuary.3)The abundance of microplastics was higher in densely populated areas.4)Factors such as effluent discharge from sewage treatment plants and inflow of tributaries affect the abundance of microplastics in rivers.The main polymer types of microplastics were polypropylene(PP),polyethylene(PE),and polyvinyl chloride(PVC).Both the abundance and polymer types of microplastics show a positive correlation between the surface waters and floodplain sediment samples,indicating that the microplastics in surface waters and floodplain sediments come from the same source.The present study demonstrates that the abundance,distribution,and sources of microplastics might be affected by geology,hydrogeology,land use types,and anthropogenic activities.This study provides basic data for the study of microplastics in rivers and provides a reference for the establishment of microplastic control measures.

Outlines of New Global Geochemical Mapping Program

Since 1988,great efforts and enthusiasm had been paid by applied geochemists in the implementation of global geochemical mapping through the International Geological Correlation Program＇s Projects 259 and 360,and the Task Group on‘Global Geochemical Baselines＇ established by the International Union of Geological Sciences（IUGS）,in collaboration with the International Association of Geochemistry（IAGC）.But how to use extremely low-density sampling to obtain a global picture of the distribution of most elements in the periodic table in a reasonably short time is still a great challenge faced by the applied geochemistry community.It will depend on the continuous development of new mapping concept,and the advisable and courageous innovation of methodology for searching other suitable sample media and sampling layout.Based on the encouragement results obtained from the representativeness study of delta sediments conducted at the mouth of Yangtze River,and at the mouths of its four major tributary,it is expected to broadly apply the geochemical fractal self-similarity nature to main rivers and their estuaries with catchments up to hundreds of thousands or over a million square kilometers in the world.With this new mapping concept,a new outlines of a Global Geochemical Mapping Program was advanced and the establishment of an International Research Center of Global Geochemical Mapping was also suggested to facilitate the programs implementations.