| Objective: Microplastic is generally defined as plastic particles with size<5 mm in the environment,and is a new type of pollutant widely existing in people’s living environment and natural environment.Researchers found the existence of microplastics in air,water,soil and other natural environmental media,as well as a variety of aquatic organisms,poultry and even human lung tissue,blood,lotion,feces and other biological samples.In this study,the nasal lavage fluid of couriers and office attendants was used as a biological monitoring tool for human inhalation exposure of microplastics.The microplastics in the nasal lavage fluid of two groups of people were separated,extracted,qualitatively and quantitatively detected and analyzed,revealing the distribution characteristics of microplastics in the nasal lavage fluid of human body,and the distribution characteristics of microplastics in the nasal lavage fluid of couriers and office attendants were compared and analyzed,It provides reference for the subsequent assessment of the human inhalation exposure characteristics of microplastics and the subsequent risk assessment and pollution prevention and control of microplastics.Methods: In this study,30 couriers and 30 office workers were randomly selected as the subjects,and each subject was investigated with questionnaires and nasal lavage samples were collected.The separation and extraction methods of microplastics in nasal lavage were optimized and compared,and the separation and extraction effects of different digestive systems on microplastics and the recovery rates of three standards were compared.Select a better digestion system to separate and extract the microplastics in the nasal lavage fluid of two groups of people,and conduct qualitative and quantitative analysis of the extracted microplastics through the laser infrared imaging system.Use Excel 2010 to sort out the test results and data,and use SPSS 20.0 to carry out statistical analysis on the data.Prescribed inspection level α as 0.05.Results: The optimized experimental results showed that the digestion effect and standard recovery of 10% KOH digestion system were higher than those of 30% KOH digestion system experimental group.In this study,a certain amount of microplastics was detected in the nasal lavage fluid of both groups of people,and the abundance of the micro-plastics in the courier group ranged from 4.10 to 84.45 items/g,with an average abundance of 37.08 ± 25.56 items /g.The abundance of microplastics in the office staff group ranged from 9.25 to 131.86 items /g,with an average abundance of 68.87 ± 44.04 items /g.The particle size of microplastics in nasal lavage fluid of two groups is mainly distributed in 0～1000 μm.Within the particle size of the range of 0～100 μm,the test results of two groups showed that the proportion of microplastics in the nasal lavage fluid is more than 70%,the proportion of microplastics of the courier group and the office staff group is73.29% and 81.61% respectively,and the proportion of microplastics in the range of 100～200 μm is 22.32% and 12.59% respectively,and the proportion of microplastics within the particle size range of 200～500 μm is 4.15% and 5.73% respectively,and the proportion of microplastics larger than 500 μm is 0.14% and 0.07% respectively,which are less than 1%.A total of 12 types of microplastic components were detected in the study,including polyamide(PA),polyethylene terephthalate(PET),polypropylene(PP),polyethylene(PE),polyvinyl chloride(PVC),polyurethane(PU),polycarbonate(PC),polystyrene(PS),polytetrafluoroethylene(PTFE),polymethylmethacrylate(PMMA),polylactic acid(PLA),and ethylene vinyl acetate copolymer(EVA).The morphology of microplastics observed in the study is mainly fragment,fiber,film and tube.The appearance colors of microplastic mainly include black,blue,transparent,red and white.Conclusion:(1)The digestion effect of 10% KOH(48h)digestion on nasal lavage,micro plastic recycling and method precision were better than those of other digestion groups in the experiment.(2)Multiple microplastics were detected in the nasal lavage fluid of both groups of people,with polyamide(PA),polyethylene terephthalate(PET),polypropylene(PP),polyethylene(PE),and polyvinyl chloride(PVC)as the main distribution types,with particle sizes mainly ranging from 0 to 200 μm,the forms of microplastics are mainly fragmented,fibrous,thin film,and tubular,with colors mainly black,blue,transparent,red,and white.The research results revealed the average abundance,particle size,component types,and shape distribution characteristics of microplastics in nasal lavage fluids for different occupational groups,both indoor and outdoor.(3)The study showed that the average abundance of microplastics in nasal lavage fluid of office staff group was higher than that of courier group,and statistical verification showed that the average abundance distribution of microplastics in nasal lavage fluid of two groups was different(p<0.05). |
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