深圳市土壤多环芳烃背景值及其源解析

Soil Background Content and Source Analysis of PAHs in Shenzhen

    摘要
  • 摘要:
      目的  精细化描述深圳市土壤多环芳烃（PAHs）的背景值和空间分布情况。
      方法  采用环境单元法和网格法，在深圳市不受或很少受人类活动影响的基本生态控制区内布设了450个土壤表层点位和50个典型剖面点位。通过多点增量采样法，最终采集500个表层土壤样品和100个剖面土壤样品。利用SPSS统计分析了表层土壤样品和剖面土壤样品的PAHs含量，探究了表层土壤PAHs的背景值与土壤理化性质的相关性，分析了表层土壤PAHs的来源。
      结果  ①深圳市自然背景下表层土壤PAHs浓度变化范围为1.1 ~ 1004.19 μg kg−1（95%分位值为30.82 μg kg−1，土壤干重）。表层土壤PAHs中5环的占比为29.58%，占比最高。其次为3环和6环，占比分别为22.70%和20.23%。②50个剖面点位上土壤表、中和底层的PAHs总量的95%分位值分别为21.38 μg kg−1、12.34 μg kg−1和15.15 μg kg−1，平均值分别为9.35 μg kg−1、5.84 μg kg−1和6.42 μg kg−1，表层含量明显高于中层和底层。③表层土壤PAHs含量与pH、阳离子交换量、有机质、黏粒和粉粒等土壤理化性质含量的相关性较为显著，而与容重和砂粒含量的相关性不显著。④表层土壤PAHs主要源头可能为交通源、煤炭燃烧和自然源，其贡献率分别为51.21%、18.42%和7.58%。
      结论  交通、煤炭燃烧等人为因素影响基本生态控制区的大气沉降的组分特征，从而改变表层土壤PAHs背景含量。建议净化交通尾气，降低土壤PAHs的背景值。

     

    Abstract:
      Objective  The aims were to get the soil background content and spatial distribution of PAHs in Shenzhen.
      Method  Based on environmental cell and grid methods, 450 soil surface and 50 typical soil profile sites were set up in the basic ecological control line area which was not or rarely affected by human activities. 500 surface samples and 100 deep samples were collected by multi-point incremental sampling method. The PAHs content of surface soil and profile soil were statistically analyzed. The correlation between the background value of surface soil PAHs content and the physical-chemical soil properties was explored, and the source of surface soil PAHs was analyzed by SPSS.
      Result  ①Concentrations of PAHs in the surface soil ranged between 1.1 and 1004.19 μg kg−1 dry weight, (95% fraction value 30.82 μg kg−1) in the basic ecological control line area. Those with 5 rings in top soil were dominant, accounting for 29.58% of the total PAHs. Then followed by 3 and 6 rings, which accounted for 22.70% and 20.23%, respectively. ②The 95% fraction PAHs values from the top layer to the bottom layer at vertical soil profile were 21.38 μg kg−1, 12.34 μg kg−1 and 15.15 μg kg−1, respectively. And the average values from the top layer to the bottom layer at vertical soil profile were 9.35 μg kg−1, 5.84 μg kg−1 and 6.42 μg kg−1, respectively. The top layer had the largest PAHs content. ③The content of PAHs in the surface soil was significantly correlated with pH value, organic matter, moisture, cation exchange capacity and clay contents. But it’s not related with the bulk density and sand content. ④The sources of PAHs based on principle factor analysis indicated that vehicle exhaust, coal combustion and background were the major PAHs source, which contributed to 51.21%, 18.42% and 7.58% of the total PAHs release, respectively.
      Conclusion  Human factors such as traffic and coal combustion influenced the air component. Thus, the background contents of PAHs in the surface soil were changed by the air deposition. It was suggested that we should purify traffic exhaust to reduce the background value of PAHs in soil.

     

    • HTML全文
    • 参考文献(39)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回