Determination of heavy metals and polycyclic aromatic hydrocarbon concentrations in soil and in the leaves of plant (Eucalyptus) of selected locations at Kirkuk—Iraq

Abstract

The average concentrations of heavy metals (Pb, Cu, Ni, Cr, and Cd) with the polycyclic aromatic hydrocarbon (PAH) concentrations in soil and in the leaves of plant (Eucalyptus) at Kirkuk Oil Refinery and around were determined in 15 selected locations using GPS. The pickings up of samples were carried out in two periods in October 2010 and March 2011. The heavy metal concentrations in soil were relatively higher in March than in October, while the reverse was true for the heavy metal concentrations in the leaves of plant (Eucalyptus); they were relatively lower in March than in October. It is believed that such finding is obvious due to high wind speed and rainfall during the winter months (i.e., March) which wash and remove the pollutants from the air and the leaves to the soil. “Compared with results of other studies, the concentration levels of determined heavy metals show values within or lower than these studies’ results, except for the concentration of Cd in soil which was higher at the two periods were higher. The average concentrations of polycyclic aromatic hydrocarbons (PAHs) in soil indicate 3.5 ppb in October, while in March 14.2 ppb, while in the leaves of plant (Eucalyptus) indicate 37.1 ppb in October, while in March 165.2 ppb. The model of cumulative effect of heavy metals and PAHs, for soil and the leaves of plant (Eucalyptus) which were determined by geographic information systems (GIS) for both sampling periods, show distribution of concentration toward wind directions and away from the site of Kirkuk Oil Refinery e.g., SW direction. This indicates the meteorological conditions represented by the wind direction and the rainfall, which plays an important role in distribution and deposition of pollutant metals.