1. Potential Exposure to Silver Nanoparticles in Children’s Consumer Products Nicolle S. Tulve 1, Marina E. Quadros 2, Kim Rogers 1, Robert Willis 1, Treye A. Thomas 3, Linsey C. Marr 2 1 U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; 2 Virginia Tech, Department of Civil and Environmental Engineering; 3 U.S. Consumer Product Safety Commission Summary Electron microscopy confirmed the presence of nAg in plush toy, fabric (baby blanket), and cleaning product (disinfecting spray) Transfer of silver to wipe materials ( to estimate dermal exposure) found that 0.3 to 23 µg/m 2 of silver transferred from products (or surfaces on which products were applied) to wipes Leaching experiments showed measurable ionic silver from plush toy, fabric, and sippy cups under conditions of normal, real-world, intended use Amount of silver released from plush toy and fabric were highest with the synthetic sweat and urine compared to tap water or saliva Components of the sippy cups released silver in either milk formula or orange juice Plush toy and fabric are predicted to be most likely sources of bioavailable silver Low potential for nAg exposure from aerosol emissions from the fabrics, plush toy, or disinfecting cleaning product Overall, silver levels to which children may potentially be exposed during normal, real-world, intended use of the consumer products tested in this study are low Abstract Background: Due to its antimicrobial properties, nanosilver (nAg) is used in many consumer products intended for use by or near children. Objective: Our objective was to determine if nAg is released from children’s consumer products under conditions of intended use and to assess the potential for exposure. Methods: From an inventory of 82 products claiming to contain nAg, 13 products (plush toy, three fabric products, breastmilk storage bags, two sippy cups, three cleaning products, two humidifiers, one humidifier accessory) were chosen for evaluation. Total extractable Ag was measured by ICPMS; leachable Ag was measured using liquids (synthetic urine, sweat, saliva; tap water; orange juice; milk formula) relevant to each product’s intended use; and electron microscopy confirmed the presence of nAg. Results: All products contained silver except for one humidifier and the humidifier accessory; however, nAg was confirmed in only the plush toy, spray cleaner, and one fabric product. Synthetic sweat and urine leached the largest fraction of total Ag from the plush toy and fabric products, 6-38%, while tap water leached the lowest amount, 0.5-2.6%. Sippy cup components leached Ag in both milk formula and orange juice. No relationship was found between pH and the level of Ag leached. Most, if not all, of the Ag leached by the synthetic liquids was in ionic form, suggesting dissolution as the main leaching mechanism. There was no general trend between product aging and leaching. Between 0.3 and 23 µg/m 2 of Ag was found to transfer from products (or wiped surfaces) to the wipes. Conclusions: Levels of Ag to which children may potentially be exposed are predicted to be low, and bioavailable Ag is expected to be in ionic form. These results advance our understanding of potential exposures to nAg from children’s consumer products by providing tools to investigate nAg movement from consumer products. Product Sample Size (N) Mass Extracted for Acid Digestion (mg) (mean + std error) Total Silver Concentration (mg Ag/kg product) (mean + std error) Fabric (Sleepsuit)3501 ± 1109.8 ± 4.1 Fabric (Baby Blanket)3501 ± 1108.3 ± 1.7 Fabric (Baby Mitts)3501 ± 1104.2 ± 4.0 Plush Toy: Interior Foam6495 ± 348.2 ± 5.0 Sippy Cup #1 (Light Blue): Rubber Ring3255 ± 224.3 ± 2.9 Sippy Cup #1 (Light Blue): Transparent Cap3101 ± 49.4 ± 1.0 Sippy Cup #1 (Light Blue): White Rim3201 ± 14.9 ± 0.2 Cleaning Product (Scrubber)3505 ± 24.6 ± 0.3 Cleaning Product (Surface Wipes)92740 ± 11004.5 ± 3.0 Breastmilk Storage Bags6506 ± 10.9 ± 0.6 Plush Toy: Exterior Fur3502 ± 30.6 ± 0.1 Sippy Cup #1 (Light Blue): Outside of Cup399 ± 1ND Sippy Cup #1 (Light Blue): Inside of Cup399 ± 4ND Sippy Cup #2 (Purple): Outside of Cup357 ± 10ND Sippy Cup #2 (Purple): Inside of Cup3103 ± 5ND Sippy Cup #2 (Purple): Spout3100 ± 1ND Sippy Cup #2 (Purple): Transparent Cap637 ± 13ND Non-Nano Fabric (Control)3502 ± 2ND ProductLiquid Media Amount of Silver Leached mg Ag/kg Product (mean + std error) % Plush Toy: Exterior FurTap water Saliva Sweat Urine ND 0.03 ± 0.001 0.14 ± 0.002 ND - 5.6 24 - Plush Toy: Interior FoamTap water Saliva Sweat Urine 0.24 ± 0.02 1.77 ± 0.03 18.5 ± 1.1 17.4 ± 0.8 0.5 3.7 38.3 36.1 Fabric (Baby Blanket)Tap water Saliva Sweat Urine 1.6 ± 0.3 1.2 ± 0.1 4.8 ± 0.3 3.7 ± 0.3 1.5 1.1 4.8 3.4 Breastmilk Storage BagsMilk formulaND- Sippy Cup #1 (Light Blue): Rubber Ring Milk formula Orange juice ND 0.41 ± 0.01 - 1.7 Sippy Cup #1 (Light Blue): Transparent Cap Milk formula Orange juice 0.020 ± 0.001 0.07 ± 0.01 0.2 0.7 Sippy Cup #2 (Purple): Transparent Cap Milk formula Orange juice 0.93 ± 0.02 ND 23.5 - Fabric (Baby Blanket) Plush Toy: Interior Foam Plush Toy: Exterior Fur Figure 5. HR-TEM micrograph of interior foam from plush toy. Product Detection of Silver in Product Nanosilver Observed Presence of Biologically Accessible Silver Plush Toy: Exterior FurYes (<1 ppm)NoYes Plush Toy: Interior FoamYes Fabric (Baby Blanket)Yes Fabric (Sleepsuit)Yes Fabric (Baby Mitts)Yes Cleaning Product (Disinfecting Spray)Yes – Cleaning Product (Surface Wipes)YesNoYes Sippy Cup #1 (Light Blue): Outside of CupNoNA Sippy Cup #1 (Light Blue): Inside of CupNoNA Sippy Cup #1 (Light Blue): Rubber RingYesNoYes Sippy Cup #1 (Light Blue): White RimYes (<5 ppm)NA Sippy Cup #1 (Light Blue): Transparent CapYes (<10 ppm)NoYes Sippy Cup #2 (Purple): Outside of CupNoNA Sippy Cup #2 (Purple): Inside of CupNoNA Sippy Cup #2 (Purple): SpoutNoNA Sippy Cup #2 (Purple): Transparent CapNo Yes Cleaning Product (Scrubber)Yes (<5 ppm)NAYes Breastmilk Storage BagsYes (<1 ppm)NANo Tabletop HumidifierNoNANo Manual Ultrasonic HumidifierNoNANo Humidifier AccessoryNoNANo Results Product contains primary nAg particles ~14 nm in size and nAg aggregates of widely distributed size. Micrograph shows one large (~40 nm) multifaceted nAg and many smaller (6-15 nm) SiO 2 particles (probably a byproduct from the ashing of the fabric). Micrograph shows a nAg aggregate consisting of primary particles 15-21 nm in diameter.