Survey on physical, chemical and microbiological characteristics of PAH-contaminated soils in Iran

ABSTRACT

Polycyclic aromatic hydrocarbons [PAHs] are one of the important groups of organic micro pollutants [Xenobiotics] due to their widespread distribution and low degradability in the environment [atmosphere, water and soil]. Some PAHs exhibit carcinogenic and /or mutagenic properties and are listed by the United States Environmental Protection Agency [USEPA] and European Commission [EC] as priority pollutants. In this research three petroleum contaminated sites in Iran were selected in order to separate and classify PAH-degrading microorganisms. Samples were analysed for soil physico-chemical properties, soil particle size distribution, Ultrasonic extraction of PAH [phenanthrene] and microbial analysis. Ultrasonic extraction method was shown to be a reliable procedure to extract a wide range of PAH concentrations from different soils, e.g. clay, silt, and clay-silt mixtures. Results showed that the extraction rate of phenanthreen in mentioned different soils was in the range of 85 - 100 percent. Results showed that two of three selected sites were contaminated with phenanthrene in the range of 10 - 100 mg/kg of soil, and had a reasonable population of PAH- degrading bacteria, which were enable to adaptate and degradate a concentration range of phenanthrene between 10 and 1000 mg/kg of soil. According to results, it can conclude that, the bioremediation of contaminated soils in Iran may be considered as a feasible practice