| 不同粒径聚乙烯微塑料对农田土壤有机碳特征及其矿化的影响 |
| 摘要点击 232 全文点击 19 投稿时间：2024-03-28 修订日期：2024-07-12 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 微塑料（MPs） 土壤有机碳矿化 土壤团聚体 溶解有机质（DOM） 三维荧光光谱 聚乙烯（PE） |
| 英文关键词 microplastics （MPs） soil organic carbon mineralization soil aggregate dissolved organic matter （DOM） three-dimensional fluorescence spectrum polyethylene（PE） |
|
| 中文摘要 |
| 农田微塑料污染已经成为当前备受关注的热点问题.通过开展为期180 d的室内土壤培养实验,旨在探明粒径水平[mm级（mMP）、μm级（μMP）和nm级（nMP）]对聚乙烯微塑料（PE-MP）介导的土壤有机碳（SOC）矿化和各特征组分含量等变化的影响及其潜在机制.结果表明,PE-MP虽然在短期内（0~13 d）促进了SOC矿化,但在长期内（180 d）抑制了SOC矿化,且PE-MP的粒径越大,抑制效果越显著；PE-MP显著提高了SOC在大（>2 mm）、小（0.25~2 mm）团聚体中的分布比例,而减少在微团聚体和粉黏粒组分中的分布比例,其中较大粒径的PE-MP（mMP和μMP）作用效果更明显,可见PE-MP增强较大团聚体对SOC的物理保护可能是其降低SOC矿化的一个关键机制；大粒径PE-MP（mMP）显著增加了土壤中活性有机碳[易氧化有机碳（ROC）和溶解性有机碳（DOC）]的含量,而小粒径PE-MP（nMP）则显著降低了DOC含量；PE-MP显著提高了轻组有机碳（LFOC）含量,而显著降低重组有机碳（HFOC）含量,且粒径越小,降低的程度越显著；此外,PE-MP显著降低溶解性有机质（DOM）的腐殖化程度,且粒径越小,降低的程度越高.利用相关性分析和结构方程模型进一步揭示粒径大小通过介导PE-MP对各有机碳特征组分含量、DOM腐殖化程度和大、小团聚体中SOC比例等的影响,进而影响最终的SOC矿化强度（CO2累计排放量）.综上,大粒径PE-MP有利于提高农田中SOC保持和抑制其矿化,但随着PE-MP粒径的变小,该有利效应会不断消失,甚至产生不利影响.研究结果能够为科学评估PE-MP在农田中的环境效应和做好其污染防控提供了有价值的科学理论依据. |
| 英文摘要 |
| The contamination of agricultural fields by microplastics （MPs） has emerged as a prominent issue of current concern. A 180-day indoor soil cultivation experiment was conducted to investigate the effects and potential mechanisms of various particle sizes [millimeter-scale （mMP）, micrometer-scale （μMP）, and nanometer-scale （nMP）] of polyethylene microplastics （PE-MP） on the mineralization of soil organic carbon （SOC） and changes in its characteristic components. The results indicated that while PE-MP initially （0-13 days） promoted SOC mineralization, it inhibited it over the long term （180 days）, with larger PE-MP particles exhibiting a more pronounced inhibitory effect. PE-MP significantly increased the proportion of SOC distribution within large （>2 mm） and small （0.25-2 mm） aggregates while reducing it in micro-aggregates and silt-clay fractions, with larger-sized PE-MP （mMP and μMP） showing a more pronounced effect, suggesting that the physical protection of SOC by larger aggregates may be a key mechanism for reducing SOC mineralization. Larger-sized PE-MP （mMP） significantly increased the content of active organic carbon [readily oxidizable organic carbon （ROC） and dissolved organic carbon （DOC）] in soil, whereas smaller-sized PE-MP （nMP） significantly decreased DOC content. PE-MP notably increased the content of light fraction organic carbon （LFOC） while significantly decreasing that of heavy fraction organic carbon （HFOC）, with the degree of reduction becoming more pronounced with decreasing particle size. Furthermore, PE-MP significantly reduced the humification degree of dissolved organic matter （DOM）, with smaller particle sizes leading to higher reductions. Correlation analysis and structural equation modeling further revealed that particle size mediated the differential impacts of PE-MP on the contents of various organic carbon characteristic components, degree of DOM humification, and the proportion of SOC in large and small aggregates, thereby influencing the ultimate intensity of SOC mineralization （cumulative CO2 emissions）. In summary, larger-sized PE-MP facilitated SOC retention and inhibition of its mineralization in agricultural fields； however, as particle size decreases, this beneficial effect may diminish and even become detrimental. These findings provide valuable scientific theoretical foundations for the scientific assessment of the environmental effects of PE-MP in agricultural fields and for effective pollution prevention and control measures. |
|
|
|
