1. Issues and background
1.1 Oil pipe leakage in Iraq
In 2006, in Iraq of pollution with crude oil have the total amount of oil spilled is 565,149 m³ and the quantities of liquid and dry gas leaked were 3560 tons as a result of 113 sabotage accidents of the pipeline in 7 provinces. Most of the incidents were in Baghdad, Kirkuk, Salahuddin, and Basra. On the other hand, fire accidents are continual in an average of 20 days during 2006 and mostly in January, August and September. The contaminated soil with crude oil looks like black film or oil droplets splashing from the pipes that have been blown up. The percentages of hydrocarbon compounds in soil samples in light polluted soil were 0.02-0.08% and 0.49-13.2% in highly polluted soils. These percentages decreased with the depth of soil (Ghazi, M.M. and Aqeel, R.L., 2014)
1.2 Impact due to pipe leakage
The toxicity of the hydrocarbon components that can affect the soil properties and plant growth can be identified as follows:
i. Lack of oxygen in soil caused by high concentrations of hydrocarbon gases and CO2 that will affect biological processes of plant roots and microorganisms. This will result in the infertile soil.
ii. The heavy hydrocarbon blocks soil pores and consequently decreasing the permeability or porosity and water movement, and increase the difficulty of plant’s roots penetration. The plant can’t grow in this particular polluted soil.
iii. Spoilt the soil structure and decreasing water holding capacity. Thus the soil dry and are not suitable for living organism. Lack of water will result to die as water are an important component in all living organism.
iv. The nutrients that should be used by plants due to element competition and pH variation will be depleted. In Iraq, an experimental study was conducted on plates of clay soil that contaminated with kerosene and gas oil (5% contamination), refer Al-Azaawi (Al-Azaawi, D. F. 2000). The results showed that these two materials have adversely affected the production of yellow corn. In the experiment, it was found that the increase of the production is related to the decomposition rate of the oil products, and the decreasing of the infiltration rate to the decreasing of the pollution concentration. Meanwhile, there was no variation in the pH and electrical conductivity of polluted soils. (Al-Khafaji, A.A., Askar, S.R., and Kasal, S.M., 1986; Ellis, R., and Adams, R.S., 1961). Thus proving that this problem will give some impact in the future by decrease the soil fertility.