Volatile Methylsiloxanes

Volatile methylsiloxane (VMS) compounds are low molecular weight materials with significant vapor pressure under ambient environmental conditions. Although these products are primarily used in manufacturing higher molecular weight polydimethylsiloxanes, the cyclic VMS materials are also used in cosmetics and other personal care products as carriers and emollients. VMS volatilizes into the atmosphere from these consumer applications, and some also enters the surface waters through sewage treatment plants (STPs). This chapter focuses on the environmental fate and effects of VMS in the atmospheric and aquatic ecosystems. Environmental fate models of VMS in air and sewage treatment plants are described and compared with environmental monitoring data. Laboratory programs are discussed to evaluate toxicity and fate in aquatic ecosystems, and an assessment of aquatic risk is presented.