title: Rare earth elements and select actinoids in the Canadian House Dust Study.
abstract: Nationally representative baseline data are presented for rare earth elements (REE), thorium (Th) and uranium (U) in house dust sampled from 1025 urban homes, in units of concentrations (μg g-1), loadings (μg m-2), and loading rates (ng m-2d-1). Spearman rank correlations indicate that, in addition to outdoor sources, consumer products and building materials can influence indoor dust concentrations of REE, Th, and U. Correlations (P<.01) with numbers of occupants, dogs, and cats suggest soil track-in. Correlations (P<.01) with hardwood floors suggest release of REE additives used in pigments and coatings during daily wear and tear. Concentrations of light REE are elevated in smokers' homes compared to non-smokers' homes (P<.001), suggesting that a key source is "mischmetal," the REE alloy used in cigarette-lighter flints. Indoor sources include geological impurities in raw materials used in consumer products, such as U and Th impurities in bentonite clay used in cat litter, and REE impurities in phosphates used for a variety of applications including dog food and building materials. Median gastric bioaccessibility (pH 1.5) of most REE in dust ranges from about 20% to 29%. Household vacuum samples correlate with fresh dust samples from the same homes (P<.001 for all investigated elements).
authors.affiliation: Exposure and Biomonitoring Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.|Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, ON, Canada.
authors.forename: P E
authors.identifier: 0000-0001-6748-4255
authors.initials: PE
authors.lastname: Rasmussen
authors.affiliation: Exposure and Biomonitoring Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Levesque
authors.affiliation: Exposure and Biomonitoring Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Chénier
authors.affiliation: Exposure and Biomonitoring Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.|Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, ON, Canada.
authors.forename: H D
authors.initials: HD
authors.lastname: Gardner
mesh_terms: D008671:Actinoid Series Elements / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D000818:Animals; D002170:Canada; D002947:Cities; D004391:Dust / Q000032:analysis*; D004784:Environmental Monitoring; D005430:Floors and Floorcoverings; D006798:Housing; D006801:Humans; D008674:Metals, Rare Earth / Q000032:analysis*; D057805:Pets
chemical_list: D008671:Actinoid Series Elements; D004391:Dust; D008674:Metals, Rare Earth
keywords: actinides; dissipative losses; exposure assessment; indoor environments; lanthanides; rare earth metals