An approach to the environmental prioritisation of volatile methylsiloxanes in several matrices

Siloxane-based compounds are widely used in personal care, pharmaceutical and household products as well as in industrial applications. Among the wide variety of these chemicals, special attention has been given to volatile methylsiloxanes (VMSs). These compounds have been extensively detected in several environmental compartments, as they are not effectively removed from wastewater and may migrate through different matrices and being lipophilic, bioaccumulate and biomagnify in living organisms. In this work, a prioritisation methodology for several VMSs in different environmental matrices was applied, estimating a hazard quotient by combining exposure evaluation through measured or predicted environmental concentrations (MEC or PEC) and effects using ecotoxicity data to establish no effect concentrations (PNEC). VMSs show quite different hazard potentials in the environment: for linear VMSs it is not considerable, while for cyclic VMSs the hazard is disperse. D4 and D5 may have adverse effects in water, as well as D5 and D6 in sediments. This first multi-matrix approach for the prioritisation of VMSs sets the ground for more accurate studies in the future, provided that more field-based data are reported.