Characterization And Source Analysis Of Macroplastic Debris And Microplastics In Lake Environment

With the wide use of plastic products,plastic waste is also increasing.And all of that plastic waste ends up in the environment as a potential source of microplastics.While some macroplastic debris can be identified by the naked eye,some are just part of the macroplastic debris itself and cannot be identified directly by the naked eye.In addition,these macroplastic debris are more difficult to identify as they break into smaller microplastics due to human and natural processes.Although some scholars have done some research on the source of microplastics,few people have studied the main application of the same material microplastics in the environment,and there is no reliable and feasible detection index to trace the source of microplastics.Therefore,this study combined with plastic products and environmental samples to summarize the traceability tracking methods of plastics and microplastics,and constructed an indicator system for the traceability tracking of macroplastic debris and microplastics,which verified the feasibility of reliable identification of the traceability of macroplastic debris and microplastics in the actual environment.The specific conclusions of this study mainly include:Based on the raw materials(plastic products),literature review and field investigation,the detection methods and reliable detection index system for identifying the physical and chemical characteristics of micro-nano-sized microplastics with macroplastic debris and smaller sizes were summarized.The identification methods based on non-instrumental analysis and instrumental analysis are summarized.The index schemes of macroplastic debris and microplastics suitable for different research needs were sorted out.For macroplastic debris with a size of more than 5mm,a large number of plastic samples and a mass of more than 5mg,non-instrumental analysis was mainly used for preliminary analysis.The visual method is mainly used to determine the appearance(transparency,color,shape,touch,mechanical properties)and use of plastics.Other methods,such as visual,density,and burning,are combined to determine the composition of the plastic.Color rendering isalso primarily used to identify plastic materials.For microplastics with a size of less than 5mm and no less than 1 m,the identification method mainly adopts non-instrumental analysis as auxiliary and instrumental analysis as the main method.Visual and microscopic methods are used for preliminary identification of the appearance and use of microplastics,with spectroscopy(Raman,infrared)as the main method,thermal analysis(pyrolysis)and chromatography as auxiliary methods for identification of the chemical components and structures of microplastics.Thermal analysis(phase change temperature)and microscopic analysis are used to identify the thermal and mechanical properties of microplastics.A combination of visual,spectral,thermal,microscopic,and chromatographic methods was used to trace the origin of microplastics.For nanometer microplastics with smaller particle size,the micro method is mainly used to determine the mechanics,thermo and composition to trace the origin of microplastics.In this study,baima lake water supply area in Hang Zhou city,Zhe Jiang province was selected as the research area.According to the size abundance and color abundance,the main sources of microplastics in baima lake and the fragmentation of large plastics were explored through cluster analysis.In addition,based on qualitative and quantitative analysis,physical and chemical characteristics of macroplastic debris plastic samples and microplastic samples in the research area were detected,and the specific use sources of macroplastic debris and microplastic products were identified by comparing the use classification table of plastic products in the area and the performance classification table of plastic products.The results showed that the main sources of macroplastic debris and microplastic in the water supply lake Bai Ma Lake were attributed to the packaging materials in daily life,agricultural activities and the residues in the demolition area.The total proportion was 46.97%,28.46% and14.99%,respectively.The main release sources of packaging materials are bags,boxes and cups.The proportion of packaging materials is 52.18%,28.47% and 7.78%respectively.Agricultural activities mainly include general agriculture and fishery,and the main sources of release in general agriculture are all kinds of films and zamees,accounting for 49.69% in agricultural activities.The main source of release from fishery is all kinds of nets and fishing lines,accounting for 44.18% in agriculturalactivities.The main release sources of residues in the demolition area are foam,junction boxes,wires,cables and water pipes.The proportion of residues in the demolition area is 78.08%,10.38% and 7.63% respectively.Taking Bai Ma lake microplastics of micro and nano size as the research object,the source of microplastics of smaller size was further explored by testing the physical and chemical properties.In the qualitative research,it was found that the source of microplastics of micron size was basically consistent with that of macroplastic debris and microplastics.Use for daily life packaging materials,agricultural activities and demolition area residues.The total proportion was 49.50%,24.75% and 10.19% respectively,which further proved that the smaller microplastics in Bai Ma Lake,a semi-enclosed water supply lake,originated from the crushing of microplastics.nanoscale microplastics have not been found in the selected sample points,but through the analysis of indoor non-environmental samples,traceability is feasible to some extent.This study verified the possibility of identifying the source based on the physical and chemical characteristics of macroplastic debris and microplastics and the indicator system through actual field samples,and optimized the physical and chemical detection methods of microplastics at different levels.Thus,it provides a new method to trace the use of Macroplastic debris and microplastics to their source,providing a more specific direction for the control of microplastics from source.