Assessment of siloxanes release into the environment by personal care products

Siloxanes are organic compounds that contain a backbone of alternating Si-O units linked in a cyclic or linear way, with methyl side chains attached to each silicon atom [1]. Due to their low surface tension, high thermal stability and smooth texture, they have been used in a wide variety of personal care products (PCPs), such as shampoos, hair conditioners, lotions, etc. Recent studies show that siloxanes may have toxic effects on aquatic organisms, but also on mammals. In fact, these compounds are suspected of causing impaired fertility, liver damage and oestrogen mimicry [2]. Due to their ubiquitous occurrence, bioaccumulation and toxic potential, siloxanes are compounds of concern for both environmental and human health. Therefore, it is essential to examine their concentrations in PCPs to enable a prediction of human and environmental exposure by measuring its inputs. In this work, an analytical method based on quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction followed by GC–MS was used for the analysis of eight siloxanes in PCPs. These products were chosen according to the usage patterns of the Oporto population (Portugal). Low detection limits, high average recoveries (>80%) and precision (RSD *minore di* 15%) were determined. Siloxanes were detected in most analysed samples in a wide range of concentrations. In general, higher levels of siloxanes were detected in shampoos and hair conditioners. Cyclic siloxanes were determined more frequently in the analyzed products. The human daily exposure to siloxanes was estimated, as well as the release rates of these compounds into the environment. Wash-off products represent the greater emission source. References: [1] Hong, W.-J., Jia, H., Liu, C., Zhang, Z., Sun, Y., Li, Y.-F., Environ. Pollut. 191 (2014) 175-181. [2] Wang, D.-G., Norwood, W., Alaee, M., Byer, J.D., Brimble, S., Chemosphere 93 (2013) 711–725. Acknowledgments: This work was financially supported by: Project UID/EQU/00511/2013-LEPABE, by the FCT/MEC with national funds and when applicable co-funded by FEDER in the scope of the P2020 Partnership Agreement; Project NORTE-07-0124-FEDER-000025 - RL2_ Environment&Health, by FEDER funds through Programa Operacional Factores de Competitividade – COMPETE, by the Programa Operacional do Norte (ON2) and by national funds through FCT - Fundacao para a Ciencia e a Tecnologia (Scholarship SFRH/BPD/76974/2011).