藏中矿区重金属污染土壤的微生物活性变化

微生物几乎参与土壤中的一切生物及生物化学反应,土壤微生物活性可较敏感地反映土壤中生化反应的方向和强度,是探讨重金属污染生态效应的有效途径之一。通过野外调查与采样和室内分析,研究了藏中矿区重金属污染对土壤酶活性、基础呼吸、代谢商(qCO2)和可矿化N的影响。结果表明,矿区土壤受重金属Cu、Zn、Pb、Cd不同程度污染,使得土壤酶活性、可矿化N受到抑制,基础呼吸和qCO2则受到刺激。逐步多元回归分析表明,在Cu、Zn、Pb、Cd复合污染条件下,矿区土壤重金属复合污染对土壤微生物活性的影响是复杂的;主成分分析表明,土壤总体微生物活性指标能较好地反映拉屋矿区土壤重金属复合污染状况,可作为藏中矿区土壤环境质量评价及量化分类的有效指标。

Effects of heavy metal pollution on microbial activities of mining soils in central Tibet

Microorganisms promote biological and biochemical processes of soil. Soil microbial activity can reflect soil biochemistry reaction, which can be used to discuss ecological effects of heavy metal pollution. Field investigation and sampling analysis of polluted mining soils were conducted to discuss effects of heavy metal pollution on soil enzyme activities, basal respiration, qCO2, and potential mineral N in Lawu mine of central Tibet. The results showed that mining soils were polluted by heavy metals, Cu, Zn, Pb and Cd, which led to decreases of enzyme activities and potential mineral N, and increases of basal respiration and qCO2. Multivariate stepwise regression analysis between heavy metal contents and soil microbial activities indicated that effects of heavy metal compound pollution on microbial activities were complex in Lawu mine. Principle component analysis further pointed out that total microbial activities in mining soils were feasible indicators to assess change in soil environmental quality by heavy metal pollution.