| 酸化对重金属铅和镉在土壤团聚体中分配与有效性的影响 |
| 摘要点击 1066 全文点击 177 投稿时间：2024-01-31 修订日期：2024-04-09 |
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| 中文关键词 土壤酸化 团聚体 重金属 制约因子 有效性 |
| 英文关键词 soil acidification aggregates heavy metals constraining factors availability |
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| 中文摘要 |
| 土壤团聚体是土壤的基本结构功能单元,对土壤理化性质起着重要调控作用. 酸化影响土壤的团聚过程,从而对土壤团聚体中重金属的分配与形态和有效性产生重要影响. 研究探讨了不同酸化程度黄壤和紫色土的团聚体组成特征、重金属镉（Cd）和铅（Pb）在不同粒径团聚体中的分布和活性变化规律. 结果表明,酸化降低了土壤大团聚体（>2 mm）的质量分数,未酸化土壤比酸化土壤高出约5%~15%. 黄壤和紫色土中大团聚体对重金属总量的贡献最大,贡献因子在0.31~0.47之间；黄壤中均以小团聚体（0.25~1 mm）和微团聚体（<0.25 mm）的Cd、Pb含量最高,而酸化后的紫色土则以大团聚体含量最高. 外源Pb、Cd进入土壤后,在团聚体中的分配主要受团聚体质量分数的制约. 在土壤酸化程度较高时,土壤团聚体粒径越小其重金属释放的风险越高；而土壤未酸化时,大团聚体重金属释放风险更高. 酸化驱动土壤原生矿物风化、铁氧化物和有机质淋失,从而导致的土壤团聚体组成和性质变化是制约Pb、Cd形态分配与有效性变化的重要原因. 研究结果为土壤酸化和重金属污染协同治理提供了基础依据. |
| 英文摘要 |
| Soil aggregates, the fundamental units of soil structure, crucially regulate soil physicochemical properties. Acidification alters soil aggregation, impacting heavy metal distribution and availability within aggregates. This study explores aggregate composition in differently acidified yellow and purple soils, along with the variation in the distribution and availability of cadmium （Cd） and lead （Pb） in different-sized aggregates. Acidification reduced the mass fraction of large aggregates （>2 mm）, with non-acidified soil being 5%-15% higher. In both soils, large aggregates contributed most to the total amount of Cd and Pb （contribution factors 0.31-0.47）. Yellow soil showed the highest Cd and Pb contents in small （1-0.25 mm） and micro-aggregates （<0.25 mm）, while the highest contents were observed in large aggregates in acidified purple soil. The mass fractions determined the distribution of external Pb and Cd in aggregates when entered into soils. In highly acidified soil, smaller aggregates posed a higher heavy metal release risk, while in non-acidified soil, the large aggregates showed higher Cd and Pb contents and thus a higher release risk. The alterations in the transformation and availability of Cd and Pb were attributed to the variations in soil aggregate composition and their properties driven by acidification, including mineral weathering, iron oxide leaching, organic matter loss, etc. These results provide the basis for the co-remediation of soil acidification and heavy metal pollution. |
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