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.
Indoor Air. 2017 Sep;27(5):965-976. doi: 10.1111/ina.12379. Epub 2017 Apr 10.
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 ), loadings (μg m ), and loading rates (ng m d ). 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).
本研究提供了全国范围内的住宅灰尘中稀土元素（REE）、钍（Th）和铀（U）的基线数据，以浓度（μg/g）、负载量（μg/m）和负载率（ng/m·d）为单位。Spearman 秩相关分析表明，除了室外来源外，消费品和建筑材料也会影响室内灰尘中 REE、Th 和 U 的浓度。与居住人数、狗和猫数量的相关性（P<.01）表明存在土壤带入。与硬木地板的相关性（P<.01）表明，在日常磨损过程中，颜料和涂料中的 REE 添加剂会释放出来。与不吸烟者相比，吸烟者家庭的轻 REE 浓度升高（P<.001），表明一个关键来源是“镧铈合金”，它是用于打火机火石的 REE 合金。室内来源包括消费品原材料中的地质杂质，如猫砂中膨润土粘土的 U 和 Th 杂质，以及用于各种应用的磷酸盐中的 REE 杂质，包括狗食和建筑材料。灰尘中大多数 REE 的胃内生物可利用率（pH 1.5）在 20%到 29%之间。家庭用真空吸尘器样本与来自同一家庭的新鲜灰尘样本相关（所有研究元素的 P<.001）。
