Transport of polystyrene nanoplastics in natural soils: Effect of soil properties, ionic strength and cation type.
Transport of polystyrene nanoplastics in natural soils: Effect of soil properties, ionic strength and cation type.
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DOI：
10.1016/j.scitotenv.2019.136065
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
Xiaoli Wu;Xueyan Lyu;Zhengyu Li;B. Gao;X. Zeng;Jichun Wu;Yuanyuan Sun
中科院分区：
文献类型：
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作者：
Xiaoli Wu;Xueyan Lyu;Zhengyu Li;B. Gao;X. Zeng;Jichun Wu;Yuanyuan Sun
纳米塑料作为一种新兴的污染物已经引起了人们越来越多的关注，并对环境造成了潜在的威胁。然而，对纳米塑料在自然土壤中的迁移行为的研究很少。采用柱形实验研究了土壤性质、离子强度和阳离子类型对聚苯乙烯纳米塑料（PSNPs）在荒漠土壤（DS）、黑土（BS）和红土（RS）中迁移的影响。三种土壤中psnp的出水回收率依次为DS (0% ~ 96.8%) > BS (0% ~ 87.5%) > RS（0%）。PSNPs的保留与Fe/Al氧化物含量呈正相关（DS: Fe-2.69%, Al-12.6%; BS: Fe-4.04%, Al-15.9%; RS: Fe-6.57%, Al-26.9%），与土壤pH呈负相关（DS: 9.75, BS: 6.57, RS: 4.97）。因此，土壤矿物质和pH被认为是决定PSNPs运输的关键土壤性质，因为它们对表面电荷的耦合作用会影响土壤与PSNPs之间的静电相互作用。此外，溶液离子强度的增加强烈抑制了psnp在DS（0% ~ 96.8%）和BS（0% ~ 87.5%）中的转运。Ca2+(IS: 1-5 mM)在增强PSNP保留方面比Na+(IS: 1-20 mM)更为明显。研究结果表明，PSNPs在天然土壤中的迁移和命运对土壤理化性质、离子强度和阳离子类型高度敏感，表明纳米塑料在高pH和低Fe/Al氧化物含量的土壤中具有较强的迁移能力，可能对土壤和地下水环境构成潜在风险。
Nanoplastics as emerging pollutants have caused growing concerns and posed potential threats to the environment. Nonetheless, only few studies investigated transport behaviors of nanoplastics in natural soils. In this study, column experiments were conducted to investigate the effect of soil properties, ionic strength and cation type on the transport of polystyrene nanoplastics (PSNPs) in a desert soil (DS), a black soil (BS) and a red soil (RS). The effluent recovery of PSNPs in three soils followed the order of DS (0%–96.8%) > BS (0%–87.5%) > RS (0%). The retention of PSNPs was positively correlated with Fe/Al oxides contents (DS: Fe-2.69%, Al-12.6%; BS: Fe-4.04%, Al-15.9%; RS: Fe-6.57%, Al-26.9%), whereas negatively correlated with soil pH (DS: 9.75; BS: 6.57; RS: 4.97). Soil minerals and pH were thus identified as the crucial soil properties determining transport of PSNPs, due to their coupled effects on surface charges to affect electrostatic interactions between soils and PSNPs. In addition, increasing solution ionic strength strongly inhibited the transport of PSNPs in the DS (0%–96.8%) and BS (0%–87.5%). Ca2+(IS: 1–5 mM) was more pronounced in enhancing PSNP retention than Na+(IS: 1–20 mM). Our findings highlight that the transport and fate of PSNPs in natural soils are highly sensitive to soil physicochemical properties, ionic strength and cation type, and reveal that nanoplastics have strong mobility ability in soils with high pH and low Fe/Al oxides contents, which may pose potential risks to the soil and groundwater environment.