Canadian House Dust Study: Lead Bioaccessibility and Speciation

详细信息    查看全文

• 作者：Pat E. Rasmussen ; Suzanne Beauchemin ; Marc Ch茅nier ; Christine Levesque ; Lachlan C. W. MacLean ; Leonora Marro ; Heather Jones-Otazo ; Sanya Petrovic ; Lauren T. McDonald ; H. David Gardner
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：June 1, 2011
• 年：2011
• 卷：45
• 期：11
• 页码：4959-4965
• 全文大小：847K
• 年卷期：v.45,no.11(June 1, 2011)
• ISSN：1520-5851

文摘

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 鈥渦rban background鈥?(geomean 58 渭g g^鈥?), 鈥渆levated鈥?(geomean 447 渭g g^鈥?), and 鈥渁nomalous鈥?(geomean 1730 渭g g^鈥?). Dust Pb_S concentrations in 924 homes (90%) fall into the 鈥渦rban background鈥?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 (R² = 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 (R² = 0.85; n = 12; p < 0.0001). The trend toward increased Pb bioaccessibility in the elevated and anomalous subpopulations (75% 卤 18% and 81% 卤 8%, respectively) compared to background (63% 卤 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.