Effect of Different Crude Oil Levels on A bioavailability of Some Heavy Metals in Two Different Texture Soils

Abstract

Soil polluted with crude oil is one of the most serious environmental problems in the world, which is mostly caused by human activity. Crude oil-associated heavy metals in the polluted soils are still considered as one of the major issue around the globe. Two soils were polluted with crude oil at levels of 0.0, 1.25, 2.5, 5, 10, 15 and 30 ml.kg−, then concentrations of heavy elements were added, 30 ml.kg− and 140 ml.kg− for lead and nickel and 40 ml.kg− and 150 ml.kg− for copper and zinc. When adding levels of (0, 1.25, 2.5, 5, 10, 15 and 30) ml.kg− of crude oil and (30 and 140) ml.kg− of lead and nickel, and (40 and 150) ml.kg− of zinc and copper to sandy and clay soils, it turns out a superiority in available lead concentrations over available nickel concentrations in sandy soil on the one hand, and a superiority in available nickel concentrations over available lead concentrations in clay soil when adding concentrations of 30 and 140 ml.kg− of the two elements on the other hand. It was also observed that the available form of copper concentrations were superior to the available form of zinc concentrations in sandy soil, and the available form of zinc concentrations were superior to the available form of copper concentrations in clay soil, when adding low concentrations (40 ml.kg−) and relatively high concentrations (150 ml.kg−). Generally, the results of this study varied depending on the effect of the crude oil levels and heavy metals concentrations.