微塑料对稻田土壤-水界面重金属分布及迁移的影响OA北大核心CSTPCD

Research on the mechanisms of microplastics(MPs)on the spatial distribution and migra-tion of heavy metals at the soil-water interface in paddy fields provides theoretical support and a sci-entific basis for studying the interaction between MPs and heavy metals at the micro-interface envi-ronment,as well as assessing the ecological risk.In July 2021,black soils from paddy fields in Northeast China were collected for a rice seedling culture experiment.The experimental treatments in-cluded fertilization and no fertilization,with four MP addition groups(SH,10 mm MP 40 g;SL,10 mm MP 4 g;BH,80 mm MP 40 g;BL,80 mm MPs 4 g)and a control group(CK)for each treatment.The experiment began on July 5th,2021,and lasted 73 days,with four replicates of each group.On the last day of the experiment,high-resolution in-situ information on bioavailable heavy metals at the paddy soil-water micro-interface was obtained at the millimeter scale using the diffusive gradient thin film(DGT)technique.The migration characteristics and release flux of heavy metals under the different MP treatments were evaluated based on Fick's first law of diffusion.Results show:(1)There were significant spatial distribution differences in the concentrations of bioavailable Mn,Co,Fe,Ni,Zn,Pb,Cu,and Cd at the soil-water micro-interface of paddy fields.(2)The addition of MPs significantly reduced the concentrations of bioavailable Cu(-50.7％to 8％,P＜0.001),Zn(-17.1％to-4.1％,P＜0.001),and Cd(-16.7％to-2.2％,P＜0.001).(3)The addition of MPs to soil changed the migration direction of bioavailable Cu,transforming the soil from a source of Cu into a sink,indicat-ing significant adsorption of Cu by MPs.(4)The impact of different MPs particle sizes on bioavail-able Ni varied,with larger MP particles(80 mm)increasing Ni concentration and smaller MP parti-cles(10 mm)decreasing Ni concentration.