Canadian House Dust Study: Lead Bioaccessibility and Speciation

Abstract

Vacuum samples were collected from 1025 randomly selected urban Canadian homes to investigate bioaccessible Pb (Pb(S)) concentrations in settled house dust. Results indicate a polymodal frequency distribution, consisting of three lognormally distributed subpopulations defined as "urban background" (geomean 58 μg g(-1)), "elevated" (geomean 447 μg g(-1)), and "anomalous" (geomean 1730 μg g(-1)). Dust Pb(S) concentrations in 924 homes (90%) fall into the "urban background" category. The elevated and anomalous subpopulations predominantly consist of older homes located in central core areas of cities. The influence of house age is evidenced by a moderate correlation between house age and dust Pb(S) content (R(2) = 0.34; n = 1025; p < 0.01), but it is notable that more than 10% of homes in the elevated/anomalous category were built after 1980. Conversely, the benefit of home remediation is evidenced by the large number of homes (33%) in the background category that were built before 1960. The dominant dust Pb species determined using X-ray Absorption Spectroscopy were as follows: Pb carbonate, Pb hydroxyl carbonate, Pb sulfate, Pb chromate, Pb oxide, Pb citrate, Pb metal, Pb adsorbed to Fe- and Al-oxyhydroxides, and Pb adsorbed to humate. Pb bioaccessibility estimated from solid phase speciation predicts Pb bioaccessibility measured using a simulated gastric extraction (R(2) = 0.85; n = 12; p < 0.0001). The trend toward increased Pb bioaccessibility in the elevated and anomalous subpopulations (75% ± 18% and 81% ± 8%, respectively) compared to background (63% ± 18%) is explained by the higher proportion of bioaccessible compounds used as pigments in older paints (Pb carbonate and Pb hydroxyl carbonate). This population-based study provides a nationally representative urban baseline for applications in human health risk assessment and risk management.

Determination of synthetic musk compounds in indoor house dust by gas chromatography–ion trap mass spectrometry

“…Two types of house dust samples were collected from randomly selected, urban, Canadian single family dwellings under the Canadian House Dust Study according to the procedures described previously [25,26] and briefly summarized here. Household vacuum dust (HD) samples were obtained from the vacuum systems used by the study participants as part of their regular house cleaning routine.…”

Lead from mining and mineral processing activities to the community via the air-dust pathway: An example from Mount Isa city using human health risk assessment approach

“…Group II "Mine High" in Table 128 and Figure 80 had the highest bioaccessibilities. In comparison to the findings in this study, lead carbonate, Pb hydroxyl carbonate, Pb sulfate, Pb chromate, Pb oxide, Pb citrate, Pb metal, Pb adsorbed to Fe-and Al-oxyhydroxides, and Pb adsorbed to humate were identified using X-ray Absorption Spectroscopy for dusts collected from urban dusts in Canada (Rasmussen et al, 2011). Plumbojarosite (PbFe6(SO4)4(OH)12), anglesite (PbSO4) and iron oxide absorbed Pb phases were observed in mine tailings materials in semi-arid Arizona, U.S.A (Hayes et al, 2012).…”

Occurrence and distribution of heavy metals in indoor settled particles in Lagos Metropolis, Nigeria

“…The highest level of Pb in zone 2, may probably be due to the house age with leaded paint interior and the ability of the deteriorated walls of the interior, windows, distorted doors, carpets and crevices in floor to trap heavy metals like Pb (Lindern et al, 2003;Rasmussen et al, 2011). Mn detected in zone 2 could have originated from infiltration of outdoor air, smoking, indoor cooking and activities such as cleaning, dusting, and vacuuming.…”