石油污染土壤的生态风险评价和生物修复 Ⅱ.石油污染土壤的理化性质和微生物生态变化研究

ECO-RISK ASSESSMENT AND BIOREMEDIATION OF PETROLEUM CONTAMINATED SOIL Ⅱ.CHANGES IN PHYSICO-CHEMICAL PROPERTIES AND MICROBIAL ECOLOGY OF PETROLEUM CONTAMINATED SOIL

采用常规土壤理化分析、微生物培养法以及碳素利用法(Biolog)和发光细菌生物毒性测定等新兴微生态研究方法,研究了石油污染引起的土壤理化性质和微生物功能多样性等微生态的变化。结果表明,石油污染使土壤有机质含量增加,pH降低,而对全磷、全钾、速效钾、全氮和水解氮无显著影响。平板计数显示石油污染对土壤中的细菌总量没有显著影响,但由于石油污染物的刺激作用导致污染土壤中总烃降解菌数以及芳烃降解菌数增加了几个数量级。Biolog的研究也表明,石油污染导致土壤微生物Gini指数、McIn-tosh指数和McIntosh均匀度等多样性指数增加,说明石油污染刺激了土壤中微生物的生长,使土壤中微生物多样性增加。而生物毒性试验表明,石油污染土壤对发光细菌具有毒性,其EC50为1 950μg ml-1。

Routine analyses and new biotechnologies, such as sole carbon source utilization tests （Biolog）,were applied to investigate changes in physico-chemical properties and microbial ecology of petroleum contaminated soil. Results show that petroleum contamination did not affect much soil hydrolysable N, total N, total P, available K and total K. But the observed increases in soil organic matter and decreases in soil pH, might have led to changes in microbial ecology of the soil. Although there was no significant difference found between the clean and the contaminated soils in numbers of cultivable heterotrophic bacteria and actinomycetes, hydrocarbon-degraders and PAHs-degraders in the contaminated soil were about 100 to 1 000 times higher in number than in the clean soil. Community level physiological profile using Biolog sole carbon source utilization tests was used to investigate effect of petroleum on soil microbial diversity. Diversity indices, such as Gini index, McIntosh index, and McIntosh evenness, increased in the contaminated soil. The above results indicate that petroleum contamination increased microbial diversity of the soil. Besides, the acute bio-toxicity test by the luminous bacteria method showed that the DCM/DMSO extract from the petroleum contaminated soil is toxic to the bacteria and only 1 950 μg ml^-1 in EC50.