Sunday Omenka and Adebola Adeyi measured four metals in 35 personal care products bought in Ibadan markets: 20 creams and lotions, 10 powders, and 5 eyeliners. Samples were dried, digested in aqua regia, and read by atomic absorption. Half the samples were analysed in duplicate. The four products that gave unusually high or low results were sent to two other laboratories for comparison.
Within the scope of baby lotions, oils, and powders, the collection contains two baby powders (7PP and 8PP) and four petroleum jellies labelled for babies (3CC, 7CC, 18CC, 19CC). A fifth jelly (20CC) is named for mothers, and 11CC is a general petroleum jelly. Products are listed here by sample code. This page does not name brands.
Key numbers
Values in mg/kg as printed. ND means not detected; no detection limit is printed.
Baby powders (Table 4)
| Code | Zn | Cd | Pb | Ni | Ash (%) | Moisture (%) |
|---|---|---|---|---|---|---|
| 7PP | 112,000 | ND | 468 | 5.75 | 95.9 | 0.36 |
| 8PP | 33.9 ± 0.1 | 36.3 ± 0.0 | 5.0 ± 0.0 | 0.13 ± 0.2 | 96.4 | 0.99 |
Ash above 95% in both baby powders indicates a mineral base. The 7PP lead result is supported by the inter-laboratory check in Table 11, where three laboratories report 468, 508.5, and 364.63 mg/kg. The 7PP zinc result, 112,000 mg/kg (11.2% by mass), was reported as 103,750.8 and 41,872.6 mg/kg by the other two laboratories. The 8PP cadmium result of 36.3 mg/kg was reported as 25 by the second laboratory and 0.38 by the third. That cadmium value is kept and is not used as a headline figure.
Baby petroleum jellies (Table 3)
| Code | Label in Table 1 | Zn | Cd | Pb | Ni | Moisture (%) |
|---|---|---|---|---|---|---|
| 3CC | baby jelly | 16.5 | ND | ND | 1.75 | 14.7 |
| 7CC | baby jelly | 7.50 | ND | ND | 4.00 | 12.3 |
| 18CC | baby jelly | 5.50 ± 0.0 | 0.13 ± 0.18 | 5.00 ± 0.0 | 0.13 ± 0.18 | 0.12 |
| 19CC | baby jelly | 6.75 | ND | 5.00 | ND | 4.10 |
| 20CC | jelly named for mothers | 5.88 ± 0.13 | 0.13 ± 0.18 | 2.61 ± 0.18 | ND | 3.78 |
Creams were dried at 70 to 80 °C before about 0.5 g was weighed for digestion. The paper does not say whether results are reported per dried or per as-sold mass. For the jellies above, the difference is at most about 17% (3CC, 14.7% moisture), but for the high-moisture creams in the collection (up to 87.8% moisture) it is up to about eight-fold. Cream values on this page carry that basis caveat.
Category summaries (Table 6)
| Class | n | Zn | Cd | Pb | Ni |
|---|---|---|---|---|---|
| Creams | 20 | 8.11 ± 4.3 | 0.11 ± 0.2 | 2.59 ± 2.4 | 2.12 ± 1.9 |
| Powders | 10 (printed as 5) | 11,715 ± 35,270 | 3.69 ± 11 | 49.6 ± 147 | 13.5 ± 33 |
| Eyeliners | 5 | 90.5 ± 77 | 0.15 ± 0.2 | 9.3 ± 10 | 10.2 ± 7.5 |
The powder means and SDs reproduce exactly from the ten Table 4 rows, so the printed n of 5 is a typographic error. Ranges: creams Pb ND to 6.25, Cd ND to 0.50, Ni ND to 6.25; powders Pb ND to 468, Cd ND to 36.3, Ni 0.13 to 107; eyeliners Pb 3.75 to 27.5, Cd ND to 0.50, Ni 2.75 to 22.6.
The abstract and prose give some ranges that differ from the tables (eyeliner nickel to 22.7 and 22.3, powder lead to 467, eyeliner lead from 3.73, cream zinc from 13.8), and swap the codes of two cream zinc values. Table values are used.
Methods (brief)
Samples were ground and sieved below 2 mm where solid, dried (105 °C for eyeliners, 70 to 80 °C for creams), and about 0.5 g was digested with 10 mL aqua regia in a Q-block digester at 150 °C for 30 minutes, filtered, and made up with distilled water. Metals were read on a Buck Scientific 210/211 VGP atomic absorption spectrometer. Spike recovery on two creams was 98% and 92% for lead and 91% and 95% for cadmium. Detection limits are not printed. The authors compared results with limits they attribute to WHO, Health Canada, the EU, the US, and Germany (Table 7). Only the Health Canada figures (Cd 3 ppm, Pb 10 ppm) match a primary text in this collection. Estimated daily intake and a health risk index were calculated for a 70 kg adult.
Evidence fitness
The study gives single-product total-metal results for two baby powders and four baby petroleum jellies from the Nigerian market in 2014. The lead figure for one baby powder is corroborated across three laboratories. Cadmium in the other baby powder is not. The dry-basis question limits use of the cream results on an as-sold basis. Powders are unaffected because their moisture is at most 1.2%.
Limitations
One product per code. Duplicate analysis on 17 of 35 samples. No detection limits and no certified reference material. The inter-laboratory table labels one row 02pp but carries the 5PP zinc value. The authors state no significant difference between laboratories, which the printed values do not support for all cells. The corresponding author is Adebola Abosede Adeyi (aa.oketola@ui.edu.ng, bolaoketola@yahoo.com).
Related evidence
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