Althobiti and Beauchemin 2021 - Bio-accessible lead in wheat and Miswak
Althobiti and Beauchemin measured lead isotope ratios in bio-accessible fractions from wheat, Miswak toothbrush, and Miswak fruit using batch and continuous on-line gastrointestinal leaching methods. The study is routeable for wheat and Miswak chewing-stick/toothbrush context because it links bio-accessible Pb fractions to geogenic, leaded-gasoline, industrial-emission, and coal-combustion source signatures. It is primarily source-apportionment evidence rather than a simple concentration survey.
Key numbers
| Finding | Source-reported value |
|---|---|
| Analytical target | 206Pb/207Pb and 208Pb/206Pb isotope ratios in bio-accessible Pb fractions |
| Leaching fluids | Artificial saliva, gastric juice, and intestinal fluid |
| Method agreement | Batch and on-line leaching methods gave similar results by Student’s t-test at 95 percent confidence |
| Wheat Pb concentration context cited by authors | Noqrah wheat 2000 +/- 520 ug/kg and Safeer wheat 2000 +/- 400 ug/kg from prior source data |
| Wheat source signal | Saliva leachates mainly geogenic; gastric and intestinal fluids often anthropogenic |
| Safeer wheat | Gastric bio-accessible Pb matched leaded-gasoline/tetraethyllead signatures; intestinal Pb pointed to coal combustion |
| Miswak exception | Unpolluted Miswak toothbrush and Miswak fruit contained only geogenic Pb |
| Polluted Miswak toothbrush | Roadside-exposed Miswak toothbrush showed Pb contamination matching Pb added to petrol |
Methods (brief)
The authors prepared artificial saliva, gastric juice, and intestinal fluid and applied both conventional batch extraction and a continuous on-line leaching method coupled to ICP-QMS. The instrument monitored 206Pb+, 207Pb+, and 208Pb+ signals for isotope-ratio source apportionment. Samples included wheat and Miswak toothbrush/fruit materials from Saudi Arabia-related settings.
This is a lead isotope/source-apportionment study. It does not provide a full sample-level concentration table for every wheat and Miswak sample in the accessible text layer; concentration context is cited from the authors’ prior work and must remain labeled as such.
Implications
For wheat pages, this source supports the point that bio-accessible Pb fractions can have different source signatures by simulated gastrointestinal compartment. For toothbrush/personal-care pages, Miswak chewing sticks can carry geogenic Pb when unpolluted and anthropogenic Pb after roadside exposure.
For standards work, do not pool isotope ratios as concentration values. The paper is most useful for exposure-source attribution and for deciding whether bioaccessibility methods are relevant to future extraction.
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Verification notes
The filename route was toothbrush/Pb, but the paper also contains wheat and Miswak fruit. The source page keeps wheat and Miswak separated and does not convert isotope ratios into occurrence concentrations.
Page history
The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Description |
|---|---|---|
| c1aef38 | 2026-06-02 | audit-queue: hamid2021-bacterial-plant-biostimulants-review → audited-promote |