Overview
Wan and colleagues measured twelve potentially toxic elements in 62 settled-dust samples from the Beijing urban area and used those concentrations in a US EPA-style exposure model. This is primary environmental and health-risk evidence, not food, ingredient, cosmetic, or consumer-product occurrence evidence. Its main value for the index is context: dust ingestion as a child exposure pathway, total-element method notes, and the relative contribution of arsenic, lead, and antimony to non-cancer hazard in an urban dust setting.
Key numbers
All concentration values below are from Table 2 and are reported as mg/kg in the <63 micrometer settled-dust fraction.
| Element | Sample n | Mean | Min | Max | SD | Beijing natural soil mean | Dust/soil ratio |
|---|---|---|---|---|---|---|---|
| V | 62 | 57.9 | 36.0 | 73.0 | 7.9 | 79.2 | 0.7 |
| chromium (Cr) | 62 | 86.0 | 45.0 | 179.0 | 24.8 | 68.1 | 1.3 |
| Mn | 62 | 607.1 | 373.0 | 796.0 | 79.4 | 705.0 | 0.9 |
| Co | 62 | 10.6 | 6.3 | 16.9 | 1.8 | 15.6 | 0.7 |
| nickel (Ni) | 62 | 45.2 | 24.0 | 109.0 | 16.1 | 29.0 | 1.6 |
| Cu | 62 | 138.4 | 84.0 | 356.0 | 49.6 | 23.6 | 5.9 |
| Zn | 62 | 722.7 | 382.0 | 2156.0 | 335.5 | 102.6 | 7.0 |
| arsenic (As) | 61 | 23.9 | 9.0 | 180.0 | 24.3 | 7.1 | 3.4 |
| cadmium (Cd) | 62 | 2.29 | 0.9 | 18.8 | 2.3 | 0.119 | 19.2 |
| Sb | 62 | 12.3 | 4.0 | 110.1 | 14.9 | 1.1 | 11.2 |
| Ba | 62 | 752.3 | 535.0 | 1054.0 | 131.1 | 531.0 | 1.4 |
| lead (Pb) | 62 | 167.9 | 71.0 | 396.0 | 68.2 | 25.4 | 6.6 |
The authors classify V, chromium (Cr), Mn, Co, nickel (Ni), and Ba as close to local natural-soil background, while Cu, Zn, arsenic (As), cadmium (Cd), Sb, and lead (Pb) are elevated and more strongly anthropogenic. Cadmium had the strongest enrichment signal: 67.7% of samples had local-soil enrichment factors between 20 and 40, classified by the paper as very high enrichment.
For the non-cancer health-risk model, the total hazard index was 1.8 for children and 0.25 for adults. The sample-level total HI range was 0.88-5.4 for children and 0.12-0.75 for adults; 89% of child sample-site HIs exceeded 1. The element HI order for children was As > Pb > Sb > Cr > Mn > Ba > V > Cu > Cd > Zn > Ni > Co, and As, Pb, and Sb together contributed 75% of the child total HI. Dust ingestion contributed 92% of the total child HQ and 84% of the total adult HQ. The highest cancer-risk estimate reported in the text was 3.8 x 10^-5 for As via dust ingestion, within the paper’s stated 10^-6 to 10^-4 regulatory range.
Methods (brief)
The study collected 62 settled-dust samples in spring 2015, mostly from outdoor surfaces of residential buildings in Beijing. Samples were sieved to <63 micrometers, dried at 105 degrees C for 8-12 hours, and hot-digested in concentrated nitric, perchloric, and hydrochloric acids. Co, Ni, Cu, As, Cd, Sb, and Pb were measured by Agilent 7700x ICP-MS; aluminum (Al), V, Cr, Mn, Zn, and Ba were measured by Leeman Labs Profile ICP-AES. The paper reports blank and duplicate quality control, <5% relative standard deviation precision, and reference-material recoveries near 100% +/- 5%.
Implications
Certification: Do not admit this source into product or ingredient benchmark pools. The matrix is urban settled dust, the basis is total concentration in a fine dust fraction, and the arsenic value is total As rather than inorganic arsenic.
App: Use as health/exposure context for dust ingestion, child hazard-index calculations, urban-environment source apportionment, and metal-page background. It should not populate food, supplement, cosmetic, personal-care, toy, or ingredient concentration rows.
Courses: Useful for teaching environmental matrix fit, total-element versus species-specific analytes, enrichment factors, and how an exposure model can identify arsenic, lead, and antimony as dominant hazard contributors even when several other elements are measured.
Related evidence
- Health
- Testing
- Arsenic
- Lead
- Cadmium
- Chromium
- Nickel
- Copper
- Zinc
- Manganese
- Antimony
- Barium
- Vanadium
- Cobalt
Update history
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