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Dermal transfer and environmental release of CeO2 nanoparticles used as UV inhibitors on outdoor surfaces: Implications for human and environmental health
Citation:
Clar, J., W. Platten, E. Baumann, A. Remsen, S. Harmon, C. Bennett-Stamper, T. Thomas, AND T. Luxton. Dermal transfer and environmental release of CeO2 nanoparticles used as UV inhibitors on outdoor surfaces: Implications for human and environmental health. ENVIRONMENTAL POLLUTION. Elsevier Science Ltd, New York, NY, , 714-723, (2018).
Impact/Purpose:
Current wood treatment and surface applications employing nanoscale CeO2 (UV protection) and Cu2CO3(OH)2 (antimicrobial) reflect uses with very high exposure potential and provide a unique opportunity to integrate ORD?s scientific ?niche? in the areas of exposure, health and ecological effects, and modeling. This novel product-application-based research will examine nanoscale CeO2, Cu2CO3(OH)2 formulations and their transformed products employed in wood treatment\coating by determining their release, exposure, fate, and transformation as well as their health and ecological effects. Research will critically inform the engineered nanomaterial (ENM) decision tree product and provide information to develop integrated adverse exposure pathways (AEPs) to adverse outcome pathways (AOPs) associated with current wood treatment and surface applications employing ENM CeO2 and Cu2CO3(OH)2 commercial products. Unique aspects of this research include the use of commercial nanoscale products, characterization ENM release and transformation associated with a high exposure application, and assessing the effects associated with exposure to mixtures of CeO2, Cu2CO3(OH)2 ENMs and their transformed products. Research findings will inform: i) regulatory uncertainties associated with exposure and effect risks associated with ENM employed in antimicrobial and surface applications with high exposure potential; and ii) newly initiated European Commission LIFE project NanoMONITOR effort that will inform ENM risk assessment under REACH.
Description:
A major area of growth for “nano-enabled” consumer products have been surface coatings, including paints stains and sealants. Ceria (CeO2) nanoparticles (NPs) are of interest as they have been used as additives in these these products to increase UV resistance. Currently, there is a lack of detailed information on the potential release, and speciation (i.e., ion vs. particle) of CeO2 NPs used in consumer-available surface coatings during intended use scenarios. In this study, both Micronized-Copper Azole pressure-treated lumber (MCA), and a commercially available composite decking were coated with CeO2 NPs dispersed in Milli-Q water or wood stain. Coated surfaces were divided into two groups. The first was placed outdoors to undergo environmental weathering, while the second was placed indoors to act as experimental controls. Both weathered surfaces and controls were sampled over a period of 6 months via simulated dermal contact using methods developed by the Consumer Product Safety Commission (CPSC). The size and speciation of material released was determined through sequential filtration, total metals analysis, X-Ray Absorption Fine Structure Spectroscopy, and electron microscopy. The total ceria release from MCA coated surfaces was found to be dependent on dispersion matrix with aqueous applications releasing greater quantities of CeO2 than stain based applications, 66 ± 12 mg/m2 and 36 ± 7 mg/m2, respectively. Additionally, a substantial quantity of CeO2 was reduced to Ce(III), present as Ce(III)-organic complexes, over the 6-month experimental period in aqueous based applications.
URLs/Downloads:
Free access through PubMed Central
https://www.sciencedirect.com/science/article/pii/S0048969717323914