Impact of soil washing using synthetic or biological surfactants, as liquid or foam, on long-term biodegradation potential and soil microbial biodiversity in hydrocarbon-polluted soil: An experimental study
Year: 2025
Type: article
Abstract: Total petroleum hydrocarbons (TPH) sorption in contaminated soils represent a limit for their extraction and biodegradation. Their remobilization is possible with synthetic surfactants but these surfactants are generally described as more toxic for endemic bacteria at high concentrations, and they are generally described as less biodegradable compared to surfactants of biological origin. Then, the use of biosurfactants could represent a more sustainable solution. The objectives of this study are to develop a combination of treatments based on the washing by biosurfactants, directly produced from a microbial community in a bioreactor, and the subsequent biodegradation in soils impacted by pollution with hydrocarbons (TPH, PAHs, BTEX), in comparison with a chemical surfactant (sodium dodecyl sulfate) used as foam or liquids solutions. Results highlighted better remobilization of TPH from a real contaminated soil by SDS (∼0.51 to 1.07 % of TPH as foam and liquids, respectively) compared to biologically produced surfactants (∼ 0.02 0.13 % as foam and liquids, respectively), but also a higher toxicity towards the soils bacterial community. After a biodegradation step, it appeared that the remaining contaminants were highly more degraded in the soil treated with biosurfactants compared to SDS (∼30 % biodegradation for biosurfactant conditions and 0 % for SDS), leading to a better remediation. Finally, the use of biosurfactants, even if less efficient compared to SDS for remobilization of TPH, could be interesting in the perspective of soil remediation in an on site context, provided that a second stage of natural biodegradation is considered. Environmental implications Our study highlights the potential of eco-friendly (bio)surfactants for soil remediation, reducing reliance on harsh chemical treatments. While biosurfactants showed lower initial efficiency in soil washing, they enhanced long-term biodegradation, promoting natural attenuation of hydrocarbons. This approach supports microbial communities, preserving soil health and ecological functions. Interestingly, integrating only nutrients (biostimulation) even further accelerates pollutant breakdown. Though slower than conventional soil washing methods, this sustainable strategy minimizes environmental disruption and toxic residues. The findings emphasize the viability of nature-based solutions for large-scale site decontamination, contributing to greener remediation practices and improved long-term soil recovery.
Institution: Bureau de Recherches Géologiques et Minières
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,400
OpenAlex ID: W4413289367