聚乙烯微塑料对土壤团聚体及其有机碳的影响

Effects of Polyethylene Microplastics on Soil Aggregate and Its Organic Carbon

为明确聚乙烯微塑料对土壤团聚体及其有机碳的影响,按照0、5%、10%、20%、25%的质量浓度将聚乙烯与土壤混合培养4个月后,测定团聚体组成、稳定性及团聚体有机碳.结果表明:微塑料增加[5,+∞)、[2,5)、[1,2)、[0.5,1.0)mm团聚体含量,而显著降低[0.25,0.50)、(-∞,0.25)mm团聚体含量,且质量浓度为10%的样品降幅最大,分别为30.9%和26.7%;聚乙烯增加团聚体稳定性和团聚体总有机碳.然而,聚乙烯降低团聚体可溶性和易氧化有机碳,质量浓度为25%的样品中[5,+∞)mm团聚体易氧化有机碳降幅最大(38.1%).由此,聚乙烯微塑料能增加团聚体稳定性和团聚体总有机碳,但会降低团聚体活性有机碳含量.

To explore the effects of polyethylene microplastic on soil aggregate and its organic carbon,we fully mixed the microplastic with soil according to the mass concentrations of 0,5%,10%,20%and 25%in laboratory.The aggregate distribution and stability,total organic carbon and available organic carbon were determined after 4 months incubation.The results showed that polyethylene microplastic increased contents of[5,+∞),[2,5),[1,2)and[0.5,1.0)mm aggregates but reduced contents of[0.25,0.50)and[0.25,-∞)mm,and 10%treatment decreased the most,reaching 30.9%and 26.7%respectively.The aggregate stability and total organic carbon of aggregates were increased by polyethylene microplastic.However,polyethylene microplastic significantly reduced the soluble organic carbon and easily oxidized organic carbon of aggregates,and the most decrease of easily oxidized organic carbon of aggregates was observed in 25%treatment in[5,+∞)mm aggregate,which was 38.1%.Therefore,polyethylene microplastic can increase the aggregate stability and aggregate total organic carbon to a certain extent,but reduce the aggregate active organic carbon content.