贵州省典型汞铊矿区周边农田土壤跳虫群落特征

大量的采矿活动导致矿区周边土壤重金属污染, 严重危害土壤生物安全。汞、铊等重金属元素毒性强, 相关污染的土壤生态风险鲜有研究。跳虫作为土壤环境变化指示生物, 能很好地反映土壤质量的健康状况。本研究以贵州省某汞铊矿区周边的农田土壤为研究对象, 按离矿区距离和作物类型设置4个采样区, 每个采样区种植2种作物, 每种作物农田设置3个样方。研究土壤跳虫群落结构和多样性及其影响因子。结果表明, 调查区内跳虫平均密度为12,000 ind./m²; 采样区距离矿区越近, 土壤重金属污染程度越大, 综合污染指数越高, 跳虫种数、密度、多样性和丰富度指数均呈先增加再降低的趋势; 环境因子分析表明重金属显著影响跳虫群落结构: Folsomides americanus、Isotomiella minor和Protaphorura encarpatus数量与汞、铊和砷含量呈负相关。高有机质含量能缓解重金属对土壤跳虫的影响, 但作物类型(玉米与薏仁)对土壤跳虫群落结构的影响无显著差异。本研究结果表明土壤有机质或能反向调节重金属污染对土壤跳虫群落的影响。

Community characteristics of soil collembola around a typical mercury-thallium mining area in Guizhou Province

Aims: Many mining activities can lead to heavy metal pollution in soils near mining areas, leading to negative consequences to the native soil biota. In particular, mercury, thallium, and other heavy metals are highly toxic, but the related ecological risks are rarely studied. As an indicator of soil environmental change, collembola species can be used to assess soil quality.Method: The study was conducted in an agricultural field near a mercury-thallium mining area in Guizhou Province. Four sampling areas were established according to different pollution levels and crop types, with two crops in each area and three sampling plots for each crop, in order to study the community structure and diversity of soil collembola and its influencing factors.Results: The mean density of collembola across sampling areas was 12,000 ind./m². The closer a sampling area was to the mining area, the higher level of soil heavy metal pollution and the higher comprehensive pollution index. Generally, collembola species richness, density, and the diversity and richness index initially increased, but then decreased thereafter. Analysis of environmental factors showed that mercury, thallium, and arsenic had a significant negative effect on the community structure of collembola species: Folsomides americanus, Isotomiella minor and Protaphorura encarpatus.Conclusion: High organic matter content could mitigate the effects of heavy metals on soil collembola. However, in this study there was no significant difference between maize and coix seed on soil collembola community structure. The results of this study indicate that soil organic matter could mitigate the effects of heavy metal pollution on the soil collembola community.