藏中矿区重金属污染对土壤微生物学特性的影响

Effects of Heavy Metal Pollution on Microbial Characteristics of Mine Soils in Central Tibet

土壤微生物对土壤重金属污染反应敏感,是探讨矿区土壤重金属污染生态效应的有效指标之一。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蔗糖酶、脲酶、脱氢酶和酸性磷酸酶活性、微生物生物量C(MBC)、N(MBN)和P(MBP)、土壤基础呼吸、代谢商(qCO2)及可矿化N的影响。研究表明,矿区土壤重金属Cu、Zn、Pb、Cd全量和有效含量均高于对照土壤;随着矿区土壤重金属含量增加,土壤酶活性、微生物量C、N和P、可矿化N均逐渐降低,土壤基础呼吸和qCO2则逐渐升高;土壤重金属与土壤蔗糖酶活性、脲酶活性、脱氢酶活性、酸性磷酸酶活性、MBC、MBN、土壤基础呼吸、qCO2及可矿化N具有显著的线性相关;脱氢酶活性对土壤重金属污染最为敏感,表明脱氢酶活性可作为藏中矿区土壤环境质量变化的有效指标。

Soil microbial activity plays a crucial role in soil biochemistry processes, which can be used as a useful indicator to discuss ecological effects of heavy metal pollution. Field investigation and sampling analysis of polluted mining soil were conducted to discuss effects of heavy metal pollution on soil enzyme activity, microbial biomass C, N and P, basal respiration, metabolic quotients （qCO2）, and potential mineral N in Lawu mine, central Tibet. The results showed that total and available contents of heavy metals were significantly higher in mining soils than in CK. Soil enzyme activities, microbial biomass C, N and P, potential mineral N decreased with increasing contents of heavy metals, but basal respiration and qCO2 increased with increasing contents of heavy metals. There were significant and linear correlations between soil heavy metal contents with enzyme activity, microbial biomass, basal respiration, qCO2, and potential mineral N. Dehydrogenase activity was the most sensitive to reflect changes in soil environmental quality affected by heavy metals, indicating that dehydrogenase activity might be a useful indicator for assessing change in soil environmental quality in metal mine of central Tibet.