Estimation of hydrocarbon sequestration in soils: influence of the chemical characteristics of humic substances

Soil organic matter (SOM) is a key factor controlling the fate of hydrocarbons in soils; however, there are no standardized methods to accurately predict their sequestration. This study proposes an accessible analytical tool capacity soil sequester considering chemical characteristics humic (HA) and fulvic acids (FA) SOM. The natural was modified by thermal treatments, obtaining five different soils. Their SOM fractionated into HA FA, each fraction characterized UV-Vis FTIR. soils were contaminated with hydrocarbon mixture (hexadecane [HXD], phenanthrene [PHE], pyrene [PYR]), sequestered concentration quantified. treated at 350 ºC presented seven times greater polycyclic aromatic (PAHs >100 mg∙[kg soil]-1) than that soil. significantly improved sequestration PAHs were: i) FA low molecular weight degree condensation, ii) high weight, aromaticity, aliphaticity, polarity condensation. Based on these results, two equations proposed predict, more 80% accuracy, composition through FTIR analysis HA.