There is a lack of research on soil microplastics in arid oases considering the rapid economic development of northwestern China.Here,we studied the occurrence and sources of microplastics in soil,as well as the relat...There is a lack of research on soil microplastics in arid oases considering the rapid economic development of northwestern China.Here,we studied the occurrence and sources of microplastics in soil,as well as the relationships between microplastics and adsorbed heavy metals in the Ebinur Lake Basin,a typical arid oasis in China.Results showed that(1)the average microplastic content in all soil samples was 36.15(±3.27)mg/kg.The contents of microplastics at different sampling sites ranged from 3.89(±1.64)to 89.25(±2.98)mg/kg.Overall,the proportions of various microplastic shapes decreased in the following order:film(54.25%)>fiber(18.56%)>particle(15.07%)>fragment(8.66%)>foam(3.46%);(2)among all microplastic particles,white particles accounted for the largest proportion(52.93%),followed by green(24.15%),black(12.17%),transparent(7.16%),and yellow particles(3.59%).The proportions of microplastic particle size ranges across all soil samples decreased in the following order:1000-2000μm(40.88%)>500-1000μm(26.75%)>2000-5000μm(12.30%)>100-500μm(12.92%)>0-100μm(7.15%).FTIR(Fourier transform infrared)analyses showed that polyethylene terephthalate(PET),polypropylene(PP),polycarbonate(PC),polyethylene(PE),and polystyrene(PS)occurred in the studied soil;(3)random forest predictions showed that industrial and agricultural production activities and the discharge of domestic plastic waste were related to soil microplastic pollution,in which agricultural plastic film was the most important factor in soil pollution in the study area;and(4)seven heavy metals extracted from microplastics in the soil samples showed significant positive correlations with soil pH,EC,total salt,N,P,and K contents(P<0.01),indicating that these soil factors could significantly affect the contents of heavy metals carried by soil microplastics.This research demonstrated that the contents of soil microplastics are lower than other areas of the world,and they mainly come from industrial and agricultural activities of the Ebinur Lake Basin.展开更多
In order to study the distribution of soil microplastics in the plastic film mulched farmland,the fluidization-centrifugation secondary density flotation method was optimized and improved to obtain the samples.The mai...In order to study the distribution of soil microplastics in the plastic film mulched farmland,the fluidization-centrifugation secondary density flotation method was optimized and improved to obtain the samples.The main components of microplastics were analyzed by Fourier spectrometer,and the surface morphology,porosity,particle size and abundance distribution characteristics of microplastics were studied by electron microscopy.The results showed that plastic mulch is the main source of microplastics.Its morphology mainly consists of fragments,fibers and particles.The size of debris microplastics was larger,with an average of 1.6300 mm,mainly distributed in the 0-300 mm cultivation layer while the size of particle micro plastic was smaller,with an average of 0.1400 mm.The width of fiber microplastic was 5-20μm,but the length could reach 0.2000-2.0000 mm,with an average particle size of 0.9200 mm.Fiber and granular microplastics could be seen in each soil layer.The surface layer of microplastics has a large number of pores characterized with a length of 50μm and a width of about 5-10μm,which might be an easy oxidation site for microplastics.This oxidation is continuous,making microplastics continuously decompose into smaller particles.The abundance of microplastics is negatively correlated with soil depth.The average abundance of microplastics is 161.50±5.20 pieces/100 g in 0-300 mm soil layer,which is their main enrichment area.However,the average abundance of microplastics decreases to 11.20±1.10 pieces/100 g in 400-800 mm soil depth.Moreover,the average particle size of microplastics is also linearly negatively correlated with soil depth.Microplastics with smaller particle size are easier to migrate as they pass through soil pores under the action of water and fertilizer.The research can provide s reference for understanding plastic mulch pollution.展开更多
Coastal tidal flats have received considerable attention in recent years,as they provide a direct channel for the discharge of terrestrial microplastics into the ocean.Land reclamation is occurring increasingly freque...Coastal tidal flats have received considerable attention in recent years,as they provide a direct channel for the discharge of terrestrial microplastics into the ocean.Land reclamation is occurring increasingly frequently in coastal tidal-flats;however,the environmental impacts of these activities remain unclear.Therefore,this pioneering study assessed the microplastic emission characteristics of reclamation geotextiles and performed a risk assessment accordingly.Morphological characterization of geotextile samples collected from five sites in Dongtai,China,provided evidence of sedimentary weathering.Based on several assumptions,the average abundance of microplastics in soil covered by geotextiles was estimated to reach 349137 particles/kg dry weight,with the total microplastic load in the reclaimed area estimated to be 20.678.06 t.Compared with previous studies,this research demonstrates that coastal reclamation areas store a high concentration of microplastics,aggravating marine microplastic pollution.Moreover,conditional fragmentation model results revealed that the weathering and distribution characteristics of soil microplastics in coastal tidal-flat areas exhibit spatial heterogeneity,being more easily affected by natural factors(such as tides)than those in inland areas.As a result of tides,the annual discharge of geotextile-originating microplastics from the studied areas into the ocean was approximately 2465.52960.77 t.These findings prove that the risks posed by engineering-microplastics are significant,indicating that further investigations are required on the precise laws of transfer and migration,as well as the toxicity mechanisms,in order to improve analytical techniques and policies in this field.展开更多
基金the National Natural Science Foundation of China(41873028,41501541)。
文摘There is a lack of research on soil microplastics in arid oases considering the rapid economic development of northwestern China.Here,we studied the occurrence and sources of microplastics in soil,as well as the relationships between microplastics and adsorbed heavy metals in the Ebinur Lake Basin,a typical arid oasis in China.Results showed that(1)the average microplastic content in all soil samples was 36.15(±3.27)mg/kg.The contents of microplastics at different sampling sites ranged from 3.89(±1.64)to 89.25(±2.98)mg/kg.Overall,the proportions of various microplastic shapes decreased in the following order:film(54.25%)>fiber(18.56%)>particle(15.07%)>fragment(8.66%)>foam(3.46%);(2)among all microplastic particles,white particles accounted for the largest proportion(52.93%),followed by green(24.15%),black(12.17%),transparent(7.16%),and yellow particles(3.59%).The proportions of microplastic particle size ranges across all soil samples decreased in the following order:1000-2000μm(40.88%)>500-1000μm(26.75%)>2000-5000μm(12.30%)>100-500μm(12.92%)>0-100μm(7.15%).FTIR(Fourier transform infrared)analyses showed that polyethylene terephthalate(PET),polypropylene(PP),polycarbonate(PC),polyethylene(PE),and polystyrene(PS)occurred in the studied soil;(3)random forest predictions showed that industrial and agricultural production activities and the discharge of domestic plastic waste were related to soil microplastic pollution,in which agricultural plastic film was the most important factor in soil pollution in the study area;and(4)seven heavy metals extracted from microplastics in the soil samples showed significant positive correlations with soil pH,EC,total salt,N,P,and K contents(P<0.01),indicating that these soil factors could significantly affect the contents of heavy metals carried by soil microplastics.This research demonstrated that the contents of soil microplastics are lower than other areas of the world,and they mainly come from industrial and agricultural activities of the Ebinur Lake Basin.
基金This work was supported by National Natural Science Foundation of China(Grant No.32060288)the Key R&D Projects of Xinjiang Production and Construction Corps(Grant No.2019AB007)the Special Project for Agricultural Ecological Environment Protection of Ministry of Agriculture and Rural Areas of China(2110402).
文摘In order to study the distribution of soil microplastics in the plastic film mulched farmland,the fluidization-centrifugation secondary density flotation method was optimized and improved to obtain the samples.The main components of microplastics were analyzed by Fourier spectrometer,and the surface morphology,porosity,particle size and abundance distribution characteristics of microplastics were studied by electron microscopy.The results showed that plastic mulch is the main source of microplastics.Its morphology mainly consists of fragments,fibers and particles.The size of debris microplastics was larger,with an average of 1.6300 mm,mainly distributed in the 0-300 mm cultivation layer while the size of particle micro plastic was smaller,with an average of 0.1400 mm.The width of fiber microplastic was 5-20μm,but the length could reach 0.2000-2.0000 mm,with an average particle size of 0.9200 mm.Fiber and granular microplastics could be seen in each soil layer.The surface layer of microplastics has a large number of pores characterized with a length of 50μm and a width of about 5-10μm,which might be an easy oxidation site for microplastics.This oxidation is continuous,making microplastics continuously decompose into smaller particles.The abundance of microplastics is negatively correlated with soil depth.The average abundance of microplastics is 161.50±5.20 pieces/100 g in 0-300 mm soil layer,which is their main enrichment area.However,the average abundance of microplastics decreases to 11.20±1.10 pieces/100 g in 400-800 mm soil depth.Moreover,the average particle size of microplastics is also linearly negatively correlated with soil depth.Microplastics with smaller particle size are easier to migrate as they pass through soil pores under the action of water and fertilizer.The research can provide s reference for understanding plastic mulch pollution.
基金The authors gratefully acknowledge the support provided by the National Natural Science Foundation of China(Grant No.21876044)the Fundamental Research Funds for the Central Universities(China)(No.B200202110)the Priority Academic Program Development of Jiangsu Higher Education Institutions(China).
文摘Coastal tidal flats have received considerable attention in recent years,as they provide a direct channel for the discharge of terrestrial microplastics into the ocean.Land reclamation is occurring increasingly frequently in coastal tidal-flats;however,the environmental impacts of these activities remain unclear.Therefore,this pioneering study assessed the microplastic emission characteristics of reclamation geotextiles and performed a risk assessment accordingly.Morphological characterization of geotextile samples collected from five sites in Dongtai,China,provided evidence of sedimentary weathering.Based on several assumptions,the average abundance of microplastics in soil covered by geotextiles was estimated to reach 349137 particles/kg dry weight,with the total microplastic load in the reclaimed area estimated to be 20.678.06 t.Compared with previous studies,this research demonstrates that coastal reclamation areas store a high concentration of microplastics,aggravating marine microplastic pollution.Moreover,conditional fragmentation model results revealed that the weathering and distribution characteristics of soil microplastics in coastal tidal-flat areas exhibit spatial heterogeneity,being more easily affected by natural factors(such as tides)than those in inland areas.As a result of tides,the annual discharge of geotextile-originating microplastics from the studied areas into the ocean was approximately 2465.52960.77 t.These findings prove that the risks posed by engineering-microplastics are significant,indicating that further investigations are required on the precise laws of transfer and migration,as well as the toxicity mechanisms,in order to improve analytical techniques and policies in this field.
