ABSTRACT
Contaminated lands around oil fields, especially soils contaminated by Polyaromatic hydrocarbons [PAHs] Are the common problem in these areas. PAHs such as Phenanthrene, Naphthalene, Benzo-a-pyrene are the major pollutant in the fields around petroleum refineries and arise largely as a result of coal and oil burning andother refineries activities. This causes an actual or potential threat to the environment and human, so removing them from polluted soil and water is necessary. In this regard, biological methods including "phytoremediation", as a new approach, are effective and economical. The aim of Phytoremediation in Contaminated lands is using the ability of plants to uptake, accumulate, degrade and removing toxic substances. This is a promising technology for the clean-up of petroleum contaminated soils, especially in the tropical area where climatic conditions favor plant growth and microbial activity and therefore the financial resources can be limited. Grass species are excellent candidates for Phytore mediation due to their extensive fibrous root system, which allow for more interaction between the rhizosphere microbial community and the contaminant. The present study was conducted to investigate the role of a warm season grass type, Sorghum vulgare Pers. Sudananse, in Phenanthrene, a major pollutant in soils around oil and gas fields, removal. The experiment was done in a green house scale with climatic conditions similar to mentioned region, in 16 weeks growth period. Physicochemicalparameters of agricultural soil were determined by standard methods as follows. pH and EC determination in saturated extract of soil. Micro and macroelement determination. Organic carbon content. Soiltexture by soil particle size determination. Field capacity 98% Phenanthrene from Aldrich chemical company was used as contamination source. Studies showed that contaminant limits, in the region is in the range of 13-17 mg/kg, so three concentrations of Phenanthrene, 10-15-20 mg/kg, was added to soil. Spiked soil was placed in 30 kg capacity blocks with 110x 46 cm dimensions and then Sorghum seeds were planted in 4-5 cm of surface. Treatments were as follows: Control :[Planted samples in non polluted soils]. Unp[l,2,3] Unplanted contaminated soil[10-15-20 mg/kg respectively]. P[1,2,3]: Planted contaminated soil[10-15-20mg/kg respectively] Phenanthrene content in soil and plant tissues was extracted to determine pollutant concentration in different times. The fate and presence of PAHs in plant root and rhizosphere may be predicted from their K[ow] or octanol-water partition coefficient which is characteristic for each organic compound and indicates their water solubility. Partitioning of compounds to the root surface from the soil solution is directly proportional to know values and inversely proportional to solubility