Assessment of the Migration of Polar Compounds from Petroleum-Contaminated Soil Using a Column Leaching Experiment

When petroleum leaks into soil, the polar compounds exhibit strong biological toxicity, causing serious damage to soil animals, plants, and microorganisms and potentially threatening human health. However, the systematic comprehension of the migration of polar compounds in petroleum-contaminated soil remains limited. Herein, we employed elemental analysis, stable carbon isotope analysis, and high-resolution mass spectrometry techniques to study the migration of polar compounds in petroleum-contaminated soil using a column leaching experiment. The results indicate that petroleum migration ability in soil is limited, and the compounds are primarily concentrated in the soil above 40 cm. The C/N, C/H, and delta C-13 ratios of organic matter in soils are highly affected by petroleum contamination. Meanwhile, the different compound classes show varying migration abilities, with N-1 and N1O1 compounds exhibiting stronger adsorption capacity on soil, while oxygen-containing compounds are more likely to migrate with water to deeper soil. Additionally, molecular polarity, unsaturation degree, and size are key factors affecting the migration of polar compounds in petroleum within the soil. This simulation experiment offers valuable insights into comprehending migration of polar compounds in petroleum-contaminated soil and their potential impacts for soil ecological environment.