THE RELATIONSHIP BETWEEN PETROLEUM CRUDE OIL COMPONENTS AND THE ABILITY OF BARLEY PLANT TO GROWTH AND ABSORPTION OF ELEMENTS FROM CONTAMINATED SOIL Khalil, H.M and M.A. Esmaeil Soils, Water and Environ. Res. Inst., Agric. Res. Center, Giza, Egypt. ABSTRACT This study was conducted to determine the effect of petroleum crude oil and its hydrocarbons and heavy metals components on the productivity of the crop and the absorption of some nutrients due to pollution. Two soil types of sandy and calcareous were contaminated with crude oil at a rate of 1, 2 and 3% (volume by weight). Pots were seeded with barley seeds. One month later after planting, barley plant samples were collected from each and also at the end of the experiment as well. There were high significant differences between dry weight of barley plants in non-contaminated samples (the control) and contaminated samples with different levels of crude oil. The total concentrations of nitrogen, phosphorus and potassium in plant samples and soil under study were also estimated. Their highest concentrations in the plant samples were due to the contaminated sandy and calcareous soil, while the lowest concentrations of them were due to the samples contaminated with 3% of the crude petroleum oil. Statistically there were significant differences between the non-contaminated samples (the control) and those contaminated with oil at all tested levels, which confirm the negative and harmful impact of the petroleum crude oil when polluted the soil and also on the productivity of barley crop and its nutrients content. INTRODUCTION The pollution problem is one of the most dangerous problems that face mankind in the last fifty years either in air, water or soil. There are enormous amounts of pollutants which contaminate the environment. In Egypt, unfortunately most of the industrial factories lie in and around cultivated soils. One of the most serious sources of pollution is the pollution by petroleum hydrocarbons arising from crude oil that is extracted world-wide at a rate of more than 65 million barrels per day. There have been considerable researches on the fate and effects of petroleum hydrocarbons on environment. Crude oil contains many organic compounds and also is rich in heavy metals. Investigations and researches have elucidated the toxic and carcinogenic effects of Egypt. J. of Appl. Sci., 29 (10) 2014 1042-1057