Distribution characteristics and risk assessment of polycyclic aromatic hydrocarbons in farmland soil-corn system from oil mining area of Yellow River Delta

To investigate the residual levels of polycyclic aromatic hydrocarbons（PAHs） in topsoil and corns in the Yellow River Delta oil extraction area, total 71 samples of farmland soils and 71 samples of corns were collected. The content of 16 PAHs in soils and spinach were detected. The Nemerow pollution index method and the health risk assessment model were used to assess the ecological health risks of PAHs in farmland soil. The results showed that the contents of PAHs in farmland soil, corn roots, stems, and leaves were 256.6-1936 μg/kg, 291.4-680.9 μg/kg, 324.9-527.9 μg/kg, and 289.5-2400 μg/kg, respectively. The results showed that PAHs in farmland soils were dominated by 4-6 rings. The order of PAHs enrichment coefficients in root, stem and leaf was leaf> stem> root. The correlation analysis results of the PAHs concentration in different corn tissues and the PAHs concentration in the corresponding farmland soil showed that there was very significantly positive correlation between the PAHs content in the farmland soil and the PAHs content in the corn root and stem, and the correlation coefficients were 0.98（P