Abstract
The cyclic volatile methylsiloxane, decamethylcyclopentasiloxane (D-5) is used in a large variety of personal care products. Based on the physical-chemical properties of D-5, it is likely that losses due to volatilisation may strongly influence the levels entering the aquatic environment. The aim of this study was to quantify the amount of D-5 in waste wash water, after typical application and use in a range of deodorant and anti-perspirant (AP) products. Results implied significant losses after a 24 h period (>99.9%), and suggest that the use of D-5 in leave-on products, such as deodorants/AP is not likely to contribute a significant down-the-drain emission source. An illustrative example is presented, based on data reporting the use of D-5 in a range of personal care products (both wash-off and leave-on), which suggests that the contribution of D-5 used in wash-off products to the aquatic environment may be considerably more significant. Limitations associated with our understanding of the actual D-5 inclusion levels in the products, the market share of the products containing D-5, and the variability of consumer habits, are identified as data gaps that need to be addressed in order to better refine down-the-drain emission estimates. (C) 2012 Elsevier Ltd. All rights reserved.