Larese and colleagues suspended metal powders in synthetic sweat and measured ion release and skin permeation in Franz cells. Nickel metal produced a measurable flux. Chromium metal did not. Potassium dichromate, a different chromium compound, did produce a flux. Those two chromium results are not interchangeable.
Key numbers
Donor-phase ions: nickel 27.1 ± 3.2 mg/L and cobalt 33.3 ± 3.2 mg/L. Chromium ions in the chromium-metal suspension were below 0.1 mg/L. The abstract states chromium in receiving solutions below 0.1 µg/L.
Table 1, means and standard deviations, seven replicates. Flux is µg cm−2 h−1.
| Metal | Flux | Flux SD | Lag time h | Lag SD | Kp cm/h | Kp SD |
|---|---|---|---|---|---|---|
| Nickel | 0.0165 | 0.00036 | 14.56 | 0.56 | 6.1 × 10−4 | 1.2 × 10−4 |
| Chromium metal | nd | nd | ||||
| Potassium dichromate | 7.29 | 0.25 | 12.5 | 0.89 | 1.52 × 10−4 | 0.05 × 10−4 |
The cobalt row in Table 1 prints flux 0.123 ± 0.0054, lag 1.55 ± 0.71 h, and Kp 3.70 × 10−4. The abstract prints cobalt flux 0.0123 ± 0.0054 with the same lag time. The table footnote marks the cobalt row as taken from Larese Filon et al. (2004). It is not treated as a new measurement in this paper. Both printed cobalt fluxes are flagged and neither is a headline result here.
The methods line prints potassium dichromate as .4.8% (m/v). A later sentence prints 4.5% (m/v). Both are flagged. Neither is silently corrected.
Methods (brief)
Franz cells and polarography or a related ion measurement on filtered donor phases. Nickel powder, chromium powder, and potassium dichromate are separate test articles. The cobalt experiment is cited from 2004.
Evidence fitness
Nickel flux and the chromium-metal non-detect support statements about those test articles. Dichromate is a soluble Cr(VI) salt and must not be read as the chromium-powder result.
Limitations
Abstract and table disagree on the cobalt flux by a factor of ten, and the table attributes cobalt to an earlier paper. The dichromate concentration is printed both as 4.8% and as 4.5%.
Related evidence
Update history
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