Anionic surfactants (ANS) are a heterogeneous group of amphipathic compounds characterized by linear aliphatic chains (from C8 to C18) with a polar group (sulphate or sulfonate) neutralized with a counter ion. Given the variability of their molecular composition, ANS are considered mixtures. Among ANS, the sodium laureth sulphate (SLES) is the main component of commonly used foaming agents necessary to facilitate the excavation procedures in mechanized tunnelling. However, its use raises concern for the environment considering the presence of SLES residual concentration in soil debris. In addition, the absence of a soil threshold limit for SLES in the EU legislation does not facilitate the re-use of soil debris as by products (e.g. land covering). Consequently, a huge amount of such detritus can only be discharged as a waste with economic costs. In absence of a threshold limit, the environmental risk assessment (ERA) of foaming agents containing SLES can be a possible alternative to evaluate potential negative impact on ecosystems. However, the ERA can be limited by scarce knowledge data on the real ecological effects of SLES in foaming agent treated-soils and the site-specific characteristics (e.g. soil texture, microbial activity) which can lead to different levels of exposure. This study is part of a wider project aiming to develop a suitable methodology to identify environmental acceptable levels of SLES residues in soil debris produced during the tunnelling operations in Italy. Particularly, we report the results of ERA procedures performed using SLES residues from foaming agent-treated soils from tunnelling excavation sites. The risk has been characterized based on the exposure/toxicity ratios, where the exposure levels were predicted through predictive models or measured in micro/mesoscom studies. The ecotoxicity of SLES for terrestrial organisms (earthworms and plants) were experimentally determined in this study, whereas toxicity data for the aquatic organisms were gathered from literature.
Environmental risk assessment of sodium laureth sulphate (SLES) contained in conditioning agents used in mechanized tunnelling
Grenni P;Patrolecco L;Muzzini VG;Barra Caracciolo A
2018
Abstract
Anionic surfactants (ANS) are a heterogeneous group of amphipathic compounds characterized by linear aliphatic chains (from C8 to C18) with a polar group (sulphate or sulfonate) neutralized with a counter ion. Given the variability of their molecular composition, ANS are considered mixtures. Among ANS, the sodium laureth sulphate (SLES) is the main component of commonly used foaming agents necessary to facilitate the excavation procedures in mechanized tunnelling. However, its use raises concern for the environment considering the presence of SLES residual concentration in soil debris. In addition, the absence of a soil threshold limit for SLES in the EU legislation does not facilitate the re-use of soil debris as by products (e.g. land covering). Consequently, a huge amount of such detritus can only be discharged as a waste with economic costs. In absence of a threshold limit, the environmental risk assessment (ERA) of foaming agents containing SLES can be a possible alternative to evaluate potential negative impact on ecosystems. However, the ERA can be limited by scarce knowledge data on the real ecological effects of SLES in foaming agent treated-soils and the site-specific characteristics (e.g. soil texture, microbial activity) which can lead to different levels of exposure. This study is part of a wider project aiming to develop a suitable methodology to identify environmental acceptable levels of SLES residues in soil debris produced during the tunnelling operations in Italy. Particularly, we report the results of ERA procedures performed using SLES residues from foaming agent-treated soils from tunnelling excavation sites. The risk has been characterized based on the exposure/toxicity ratios, where the exposure levels were predicted through predictive models or measured in micro/mesoscom studies. The ecotoxicity of SLES for terrestrial organisms (earthworms and plants) were experimentally determined in this study, whereas toxicity data for the aquatic organisms were gathered from literature.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
