Environmental Fate and Effects of Foaming Agents Containing Sodium Lauryl Ether Sulphate in Soil Debris from Mechanized Tunneling

A wide use of foaming agents as lubricants is required in mechanized tunneling. Their maincomponent, the anionic surfactant sodium lauryl ether sulphate (SLES), can remain in residualconcentrations in soil debris, influencing their potential reuse as by-product. This study aimed atevaluating the environmental fate and eects of a foaming product used for conditioning soils collectedfrom real excavation sites, in the presence/absence of an anti-clogging polymer, both containing SLES.Soil microcosm experiments were set-up and incubated for 28 days. Over time, soils and their waterextracts (elutriates) were collected to perform both ecotoxicological tests (Vibrio fischeri, Lepidiumsativum, Eisenia foetida, Hetereocypris incongruens, Danio rerio) and SLES analysis. The results showedthat, just after conditioning, SLES did not exert any hazardous eect on the organisms tested exceptfor the bacterium V. fischeri, which was the most sensitive to its presence. However, from day seventhe toxic eect on the bacterium was never observed thanks to the SLES decrease in the elutriates(<2 mg/L). SLES degraded in soils (half-lives from 9 to 25 days) with higher disappearance ratescorresponding to higher values of microbial abundances. This study highlights the importance ofsite-specific studies for assessing the environmental reuse of spoil materials.