Low molecular weight cyclic volatile methylsiloxanes in cosmetic products sold in Canada: implication for dermal exposure.

Low molecular weight cyclic volatile methylsiloxane (cVMS) compounds have been used in a variety of cosmetics and personal care products and many other consumer products. The study provides information on the levels of cVMSs in cosmetics and personal care products sold in Canada with an attempt to estimate the consumer dermal exposure to cVMSs from these products. The levels of four cVMS compounds, hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) were determined in 252 cosmetics and personal care products collected from retail stores in several provinces in Canada. These products included fragrances, hair care products, deodorants and antiperspirants, nail polishes, lotions, skin cleansers and a variety of baby products (baby oils, baby lotions, baby shampoos, and diaper creams). Samples were extracted with different organic solvents depending on the nature of the products followed by gas chromatograph-mass spectrometry (GC-MS) analysis. D3, D4, D5 and D6 were found in 0.8%, 4.8%, 14.3%, and 9.1% of the products, respectively. D5 was the most predominant cVMS with the highest concentration of 680 mg/g in an antiperspirant. D5 was also found to have the highest concentration in baby products (150 mg/g in a diaper cream). Several approaches were used to estimate consumer dermal exposure to cVMSs. A wide range of exposure estimates were derived as a result of the uncertainty in adsorption efficiency and penetration rates of cVMSs in human skin as well as in the degree of evaporative loss during products use.