Naphthalene partitioning from creosote of a contaminated site in Brazil

Creosote, a dense non-aqueous phase liquid (DNAPL), contains various organic constituents such as polycyclic aromatic hydrocarbons and phenols. When a leak occurs, the organic compounds spread through the water flow due to multicomponent partitioning and diffusion processes. Dissolved and sorbed phases of the contaminants are formed in both water and soil media, which is a concern in heterogeneous underground environments with low permeability regions because the contaminant plumes can be sustained via back diffusion and hinder remediation efforts. Therefore, this study shows naphthalene (NAP) partitioning in dissolved and sorbed phases. NAP was selected as a target contaminant present in DNAPL creosote. The NAP diffusion in clayey soil is also simulated. The soil samples and creosote were collected in a contaminated site from a former wood treatment plant. The results of this research represent the first experimental data that evaluate NAP sorption in soils using an aqueous solution from creosote/water equilibrium experiments. Significant retentions were observed, even in sandy soil with low organic carbon. NAP diffusion simulation in clayey lens revealed prolonged groundwater contamination, which indicates the need for a better understanding of contaminant behavior to mitigate risks to human health and the ecosystem. This study shows how crucial it is to evaluate contaminant partitioning parameters in DNAPL contaminated sites to improve remediation predictions.