Investigating the status, sources and health risks of polycyclic aromatic hydrocarbons (PAHs) in the surface soils of Ahvaz oil field

High concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface soils are a serious threat to human health and the environment. In this study, to determine the level of PAHs pollution in Ahvaz oil field, 66 surface soil samples were collected and the concentration of PAHs was analyzed by gas chromatography-mass spectrometry (GC-MS) method. The sum of PAHs16 concentration in the surface soils of Ahvaz oil field ranged from 913.50 to 44452.05 (μg/kg), with a mean of 12872.57 (μg/kg). Combustion PAHs make up a significant portion of the total concentration of PAHs, ranging from 0.61 to 0.73. The ratio of carcinogenic compounds to total PAHs ranges from 0.55 to 0.59. The average concentration of PAHs with high molecular weight (HMW) is 10573.13 (μg/kg), which accounts for 82% of total PAHs, and their origin is generally due to the combustion of petroleum fuels. The average concentration of most PAHs is higher than ERL values and lower than ERM values, indicating that sometimes biological side effects from PAHs occur. However, the concentration of Ant and BaA compounds is higher than the value of ERM, so these two compounds in most cases cause biological side effects. The toxic equivalent concentration (TEQ) in surface soil ranged from 99.44 to 5301.86 (μg/kg). ILCR is higher in children on pathways ingestion than in adults, but LCR is higher in adults than in children in pathways dermal contact and inhalation. The cancer risk (CR) for children (8.95×10-4) is higher than for adults (8.64×10-4), which shows the high potential for cancer risk in the study area.