再生水灌溉对园林土壤重金属含量及酶活性的影响

Effects of Reclaimed Water Irrigation on Heavy Metal Contents and Enzyme Activities in Garden Soil

  • 摘要:
    目的 研究再生水灌溉对园林土壤中重金属含量和酶活性的影响,可为促进生活污水回收利用提供科学依据和实践支持。
    方法 本研究选取了木荷、黎蒴和红锥的林下土壤作为实验对象,分别使用自来水、生活污水和再生水对其进行灌溉,分析比较土壤的化学性质(pH、有机质、全氮、全磷、碱解氮、铵态氮)、重金属元素(铅Pb、铬Cr、镉Cd)的含量、土壤酶活性(过氧化氢酶S-CAT、脲酶S-UE、蔗糖酶S-SC、中性磷酸酶S-NP)差异及其关系。
    结果 与自来水灌溉相比,生活污水和再生水灌溉的土壤在pH、有机质、全氮、全磷、碱解氮、铵态氮、Cr和Cd含量显著增加,而Pb的含量无显著差异(P > 0.05);生活污水和再生水灌溉处理的土壤中S-CAT和S-SC活性显著高于自来水灌溉处理,S-NP活性为自来水灌溉处理最高。冗余分析发现pH是影响Cr和Cd含量的主要因素,主成分分析和Person分析发现重金属Pb含量和S-NP活性呈现显著正相关,Cr含量与S-CAT活性、S-SC活性呈现极显著正相关,与S-UE活性、S-NP活性呈现极显著负相关,Cd含量与S-SC活性呈现极显著正相关(P < 0.01),与S-NP活性呈现显著负相关(P < 0.05)。
    结论 生活污水和再生水的灌溉能够改变园林土壤的性质,提升土壤养分含量,提高S-CAT和S-SC活性,降低S-NP活性,同时也会导致部分重金属的累积,但其含量仍低于国家标准的限定值。

     

    Abstract:
    Objective  The study investigated the impact of reclaimed water irrigation treatments on the heavy metal contents and enzyme activities in soil, which could provide scientific evidence and practical support for promoting the recycling and utilization of raw sewage.
    Methods  This study selected Schima superba, Castanopsis hystrix, and Castanopsis fissa as experimental plants and irrigated them with tap water, raw sewage, and reclaimed water. The chemical properties of the soil (pH, organic matter, total nitrogen, total phosphorus, alkali-hydrolyzed nitrogen, ammonium nitrogen), the contents of heavy metals (Pb, Cr, Cd), and soil enzyme activities (catalase, S-CAT; urease, S-UE; sucrose, S-SC) and neutral phosphatase (S-NP) were analyzed and compared, along with their interrelationships.
    Results  Compared with tap water irrigation, irrigation with raw sewage and reclaimed water significantly increased the soil's pH, organic matter, total nitrogen, total phosphorus, alkali-hydrolyzed nitrogen, ammonium nitrogen, Cr, and Cd contents, while Pb content showed no significant difference. The activities of S-CAT and S-SC were significantly higher under raw sewage and reclaimed water irrigation than with tap water. While the S-NP activity was the highest under tap water irrigation. Redundancy analysis revealed that pH was the main factor affecting Cr and Cd contents. Pearson correlation and principal component analysis indicated a significant positive correlation between Pb content and S-NP activity, while Cr content showed a highly significant positive correlation with S-CAT and S-SC activities and a highly significant negative correlation with S-UE and S-NP activities. Cd content showed a highly significant positive correlation with S-SC activity and a significant negative correlation with S-NP activity.
    Conclusion Irrigation with raw sewage and reclaimed water alters the properties of garden soil, increases soil nutrient contents, enhances S-CAT and S-SC activities, and reduces S-NP activity. However, it also leads to the accumulation of some heavy metals, although their concentrations remain below the limits set by national standards.

     

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