Combined effects of heavy metal and polycyclic aromatic hydrocarbon on soil microorganism communities

Soil contaminated sites contain a variety of pollutants, especially heavy metals and polycyclic aromatic hydrocarbons (PAHs). Interactions between heavy metals have been relatively well studied, but little is known about interactions between heavy metals and PAHs. The combined effect of heavy metals and PAHs on soil microorganism was studied in laboratory conditions and evaluated by random denaturing gradient gel electrophoresis. We extracted DNA directly from contaminated soils and then amplified the V3 sequences of the 16S rDNA. The results showed that with different culture time, the gene diversity of the single and combined contaminated soil differed as well. After 15 days of culture, the microorganisms were stimulated and accommodated. After 45 days of cultivation, the quantities of the soil microorganisms were affected. It is concluded that some of the microorganisms utilize phenanthrene as important carbon resources. Microorganisms directly isolated from soil could reflect the diversity of soil microorganism and population distribution conditions.