青藏公路沿线土壤重金属分布特征与污染风险评估

Distribution Characteristics and Pollution Risk Assessment of Soil Heavy Metals along the Qinghai-Tibet Highway

    摘要
  • 摘要:
    目的 摸清青藏公路沿线土壤重金属空间分布特征并进行污染风险评价，为沿路生态环境保护提供依据。
    方法 沿青藏公路（西宁－那曲段）选择37个典型路段进行实地调查与土壤采样，由路基向外采集0 m、50 m和100 m处的表土样品共122个，测定土壤中的镉（Cd）、铅（Pb）和砷（As）含量。分别采用内梅罗污染指数（Ip）、地累积污染指数（Igeo）和潜在生态风险指数（RI），依据国家《农用地土壤污染风险筛选值》进行重金属污染风险评价。
    结果 青藏公路沿线土壤中Cd、Pb和As的平均含量分别为0.13 ± 0.05、33.20 ± 14.64和18.10 ± 18.25 mg kg−1，均大于土壤环境背景值。从路域横向变化趋势来看，公路路基边坡底部（0 m）的土壤重金属含量显著大于50 m和100 m处，且随公路距离的增加而下降。内梅罗污染指数的范围为0.17 ~ 0.88，总体位于未超标的安全线以下，但在格尔木－唐古拉山段存在局部超警戒值的点位。三种不同重金属元素的地累积指数结果表明Cd在大多数点位为无污染到中度污染之间的范围，另外两种重金属为无污染；公路沿线的潜在生态风险指数整体上属于轻微污染水平，但在格尔木－唐古拉山段局部存在150 < RI < 300的中度污染点位。
    结论 青藏公路沿线表层土壤中Cd、Pb和As三种重金属平均值含量均高于背景值，其中Cd的污染风险相对较高。土壤重金属含量整体上与距公路水平距离呈反比，格尔木－唐古拉山段相对较高且局部存在中度污染风险。

     

    Abstract:
    Objective The aim was to elucidate the spatial distribution and pollution of heavy metals in soil along the Qinghai-Tibet Highway.
    Methods Field investigation and soil sampling were carried out along 37 typical sections of Qinghai-Tibet Highway (Xining - Naqu Section). A total of 122 topsoil samples were collected from the roadbed at 0 m, 50 m and 100 m, and the contents of cadmium (Cd), lead (Pb) and arsenic (As) were determined. Nemerow Pollution Index (Ip), ground cumulative pollution index (Igeo) and potential ecological risk index (RI) were used to evaluate the heavy metal pollution risk according to the Screening Value of Agricultural Land Soil Pollution Risk.
    Results The average contents of Cd, Pb and As in soil along the Qinghai-Tibet Highway were 0.13 ± 0.05, 33.20 ± 14.64 and 18.10 ± 18.25 mg kg−1, respectively, which were all higher than the soil environmental background values. From the perspective of lateral variation trend of road area, the soil heavy metal content at the bottom (0 m) of highway subgrade slope was significantly greater than that at 50 m and 100 m, and decreased with the increase of highway distance. The Nemerow pollution index ranged from 0.17 to 0.88, which is generally below the safety line, but there are some points of local alarm value in Golmud-Tanggula Mountain section. The results of the ground accumulation index of three different heavy metals showed that Cd was in the range from pollution-free to moderately polluted at most points, and the other two heavy metals were pollution-free. The potential ecological risk index along the highway belongs to the light pollution level on the whole, but there is a moderate pollution point of 150 < RI < 300 in the Golmud-Tanggula mountain section.
    Conclusion The average contents of Cd, Pb and As in the surface soil along the Qinghai-Tibet Highway are higher than the background values, and the pollution risk of Cd is relatively high. The content of heavy metals in soil is inversely proportional to the horizontal distance from the highway, and the Golmud-Tanggula mountain section is relatively high and local pollution risk is moderate.

     

    • HTML全文
    • 参考文献(28)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回