Proceedingsof ISEPEHH - 2009, Tirupati, India. Phytoremediation of Hydrocarbon Contaminated Soil of Oil Field Situated at Lakowa, Uppen Assam, India SureshDeka, Hemen Deka and NeelotpalSen Sarma Institute of Advanced Study in Science and Technology (IASST), Paschim Roragaon, Garchuk, Guwahati - 35, Assam,India. ABsrRAcr: A phytoremediation study was conducted taking five herbs viz. Cyperous bravdolius, Cassia tora, Ageratum conizoides, Mimosa pudica and Cymbopogon winteriaras. Results revealed that Mimosa pudica has removed maximum (86.35%) smount of total petroleum hydrocarbon GPH) liom the contaminated soif among the test plants. The amount of TPH was found lessin the top layers of the soil (i.e. 0 -10 cm depth) as compared to the bottom layer ofthe soil (i.e. l0-20cm depth). The concentration ofTPH in the herbs was found vary depending upon the plant and their parts. There was no correlation between root or shoot biomass of the plant iniespect of iptake as well as degradation of hydrocarbon from the contaminated soil. A total of 11 Poly Aromatic ilydrocaibons (PAH) was detected from the contaminated soil. Amongst them uptake of Anthracene and Benzo (Aj anthracene were detected in almost all the plants testt'd for the experiment. It was'also revealed that up taken of Benzo (A) anthracene by the root portion of Mimosa pudica was found higher whereas it was higher in the shoot portion of C winterianus. However, Cyperus brevifullia and Cassia tora did not show any uptake of-Benzo (A) anthracene in their shoot portion. Key words: Phytoremediation, Hydrocarbon, Poly Aromatic hydrocarbon, Contqmination, Oitfietd, Soil 79 Oil contaminated soil in and around exploration and spillage areas and oil refineries are still remaininga major environmentalproblem. The affect of oil spill has been frequently felt in the mining areas in the North Eastern Region of India. It causes noticeable damage to the environment and it is believed that this changes the chemical,physical and biological statusof the soil in the vicinity. It is reported that the agricultural land near the oil exploration sites are often contaminated by hydrocarbons and land become unfit for cultivation (Delia et al 2004). So, it is necessary to developniw and modern technology to restore the soil health due to contamination of hydrocarbon.Bioremediation of petroleum in soil using indigenous microorganisms has proven effective; however, the biodegradation rate of more recalcitrant and porcntially toxic petroleum contarhinants, such as Polycyclic Aromatic Hydrocarbons (pAlls), is rapid at first but declines quickly. Biodegradation of such compoundsis limited by their strong adsorptionpotential and Iow solubility. Vegetation may play an important role in the biodegradation of toiic organic chemicals(Walton and Anderson, 1990; Lappin et al, 1985, Sandmann and Loos, 1984; Hisu and Bartha, 1919; Reddy and Sethunanthan, 1983; Anderson and Walton, 1992; Aprill and Sims, 1990;Feno et al, 1994; Reilley et al, 1996). Plant may indirectly contribute to the dissipation of contaminants in vegetated soil. Soil adjacent to the root contains increased microbial population (paul and Clark 1989). Rovira and Davey (1974) found the number of bacteria in the rhizosphere to be as much as 20 times that normally found in non-rhizosphere soil. Shsrt, Gram - negative rod - shaped bacteria especially pseudomonas, Flavobacterium and Alcaligenes are most commonly found in the rhizosphere (Barber, 1984). plant roots release exudates capable of supplying amino acids, carboxylic acids, carbohydrates, nucleic acid derivatives, growth factors, enzymes and other related compounds (Alexander, 1977). Aprill and Sims (1990) srudied the effects of using deep-rooted prairie grasses to remediate soil contaminated with PAHs. They suggested that the roots of these perennial grasses may be more effective as stimulating the rhizosphere microflora due to their fibrous nature. Fibrous roots offer more root surface area for microbial colonizafion the other roots and result in a longer microbial population in the contaminated soil. Phytoremediation is a viable remediation method for petroleum.contaminated soil. The use of vegetation for remediation of contaminatedsites is attractive and eco- friendly. tleeping this in to mind, the presentinvestigation was carried cut tc study the phytoremediation potentiality of some selected herbs, which are locally available for remediation of petroleum hydrocarbons from contaminated soil of oil exploration sites. IVlethods The plant species mainly herbs and soil samples were collecte<i from the petroleum contaminated oil field situated at Lakowa, Sibsagar District of Assam (India). Soil samples were collected from the rice field situated near the influence zone of Group Gathering Station (GGS=where crude'oil is collectedfrom different wells) at diflerent distances viz. 50m, 100m, 150m, 200m, 250m and beyond 250m. Moreover, about 200 kg of soil sample of 0-15 cm depth was collected from the hydrocarbon- contaminated site where leakage of crude oil was noticed for conducting phytoremediation experiment. The collected plant species were brought to the laboratory erret preserved and maintained in the earthen pot in the g eco' house of the institute. The collected soil samples vrcrc canied aseptically to the laboralory in clean polytlreile bagsfor study. Analysis of the soil samples: Before analysis. thc collectedsoil samples were spread out thinly on a piece of stout'paper and subjected to air dry in shade free fiom dust. During the process of drying, thc lumps of ;oi&