Methylsiloxanes in children silicone-containing products from China: Profiles, leaching, and children exposure

Methylsiloxanes (D4-D6, L5-L16) were detected in children silicone-containing products (n=190, detected frequencies=46-89%) marketed in China. For the 15 target compounds, the average concentrations ranged from <LOQ - 0.005±0.007μg/g in hard toys, 0.084±0.281-22.2±29.6μg/g in pacifiers, 0.020±0.023-20.6±16.0μg/g in teethers, and 0.005±0.009-2.81±3.22μg/g in soft rubber toys. Linear methylsiloxanes were predominant in these four types of children products. In the leaching test, except for L6, the other 14 methylsiloxanes were detected (mean=0.001±0.008-0.770±2.60ng/mL) in saliva leachates for children products, with the detection frequencies ranging from 4 to 46%. The conservative mouthing exposure for children were 6.87-18.05ng/kg bw-day via pacifiers and 0.44-2.29ng/kg bw-day via teether/soft rubber toys for ∑cyclic methylsiloxanes, and 7.89-20.74ng/kg bw-day via pacifiers and 0.41-2.12ng/kg bw-day via teether/soft rubber toys for ∑linear methylsiloxanes. Methylsiloxanes conservative mouthing exposure associated with children products were 1-2 order of magnitudes lower than the sum of children's daily inhalation exposure and dust ingestion exposure in the indoor environment. The above results indicated that although methylsiloxanes, as the impurities of polydimethylsiloxane, distributed in children silicone-containing products, exposure arising from directly mouthing these products may not be the dominated pathway for children exposure of methylsiloxanes.