Lead Speciation in House Dust from Canadian Urban Homes Using EXAFS, Micro-XRF, and Micro-XRD

Abstract

X-ray absorption fine-structure (XAFS) spectroscopy, micro-X-ray fluorescence (μXRF), and micro-X-ray diffraction (μXRD) were used to determine the speciation of Pb in house dust samples from four Canadian urban homes having elevated Pb concentrations (>1000 mg Pb kg(-1)). Linear combination fitting of the XAFS data, supported by μXRF and μXRD, shows that Pb is complexed in a variety of molecular environments, associated with both the inorganic and organic fractions of the dust samples. The inorganic species of lead identified were as follows: Pb metal, Pb carbonate, Pb hydroxyl carbonate, Pb oxide, and Pb adsorbed to iron oxyhydroxides. Pb carbonate and/or Pb hydroxyl carbonate occurred in all four dust samples and accounted for 28 to 75% of total Pb. Pb citrate and Pb bound to humate were the organic species identified. The results of this study demonstrate the ability of XAFS to identify Pb speciation in house dust and show the potential to identify Pb sources from new homes versus older homes. Understanding Pb speciation and how it influences bioaccessibility is important for human health risk assessment and risk management decisions which aim to improve indoor environmental health.

Lead speciation of PM2.5 collected from Greater Cairo, Egypt and Zarqa, Jordan: An energy dispersive X‐ray fluorescence and X‐ray absorption near edge structure study

“…XANES analysis confirmed the existing of PbCrO 2 , Pb‐sorbed goethite, PbO, PbCl 2 , and Pb in different size fractions ranges from 1,000 μm to <38 μm. A recent study of Pb speciation in house dust samples collected from four Canadian urban homes has been carried out using X‐ray absorption fine structure (XAFS), micro‐X‐ray fluorescence, and micro‐X‐ray diffraction . They found that Pb was found in organic (Pb citrate and Pb bound to humate) and inorganic (Pb, Pb carbonate, Pb hydroxyl carbonate, Pb oxide, and Pb adsorbed to iron oxyhydyroxides) species.…”

Precessional Cyclicity of Seawater Pb Isotopes in the Late Miocene Mediterranean

“…Niger and Chad are the most proximal countries to the Bodélé Depression, confirming dust does not require long transport times in the atmosphere to acquire an anthropogenic signal. This validates the suspicion that approximations of natural Pb isotope signatures derived from modern dust do not represent natural Pb isotope compositions and therefore cannot be used to reconstruct past dust Pb isotope signatures (see supporting information for further discussion; Hamelin et al, 1989;MacLean et al, 2011).…”

Rare earth elements and select actinoids in the Canadian House Dust Study

“…Based on the recent unprecedented increase in extraction and manufacturing applications of rare earth elements (REE), a concomitant increase in environmental and occupational exposures to REE can be expected . It is recognized that settled house dust acts as a sink for metal compounds used in consumer products and building materials, and as the commercial importance and prevalence of REE in consumer products grows, information about REE concentrations in house dust is likely to become increasingly relevant. To date, almost nothing has been published on REE concentrations in settled house dust, apart from a small study in New Zealand which reported on Sc, La, Ce, and Sm concentrations in 11 urban homes.…”