Concentrations and source identification of polycyclic aromatic hydrocarbons (PAHs) in surface soil of industrial areas in city of Hamedan, Iran

Polycyclic aromatic hydrocarbons are a large group of ubiquitous environmental pollutants with teratogenic, mutagenic and carcinogenic potential, which are products of incomplete combustion and pyrolysis of fossil fuels and combustion of organic matter. This study was performed to determine and identify the origin, concentration and source of PAHs compounds in surface soils of industrial areas, Hamedan, Iran, in 2021. In this descriptive study, 36 surface soil specimens were collected from 12 sampling sites of industrial areas. After extraction of analytes based on the soxhlet method, the gas chromatography/mass spectrometry (GC–MS) method was used for the determination of PAHs compounds in the samples. Molecular diagnostic ratios (MDRs) were used to determine the origin of PAH compounds. Furthermore, the amounts of pH, electrical conductivity (EC) and total organic carbon (TOC) parameters of soil samples were measured. Statistical data processing was performed using SPSS statistics 20 software. The results showed that the total concentrations of 16 identified isomers ranged from 2417 to 16279 µg/kg with a median of 7675 µg/kg and with a dominance of 4-6 rings hydrocarbons (66% of total PAHs). Furthermore fluoranthene (Fla), pyrene (Pyr) and benzo(b)fluoranthene (BbF) were the most abundant compounds in soil and the average of compounds such as benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), benzo(a)pyrene (BaP) and dibenzo(a,h)anthracene (DB(ah)A) were higher than MPC established by The Dutch Ministry of Health, Welfare and Sport (MHWS). The results of the MDRs method indicated that both pyrogenic and petrogenic sources are the origin of PAHs in the study area. The result of this study indicates the high impact of anthropogenic activities on the contamination of the study area with PAH compounds. Thus, appropriate soil remediation (especially bioremediation) approaches should be considered.