Quality control of selected cosmetics marketed in Libya for traces of toxic heavy metals: urgent need of guidelines harmonization

Overview

This Mediterranean Journal of Pharmacy & Pharmaceutical Sciences study quantifies four heavy metals (lead, total arsenic, cadmium, nickel) by atomic absorption spectroscopy (Shimadzu AAS-6300) in 12 cosmetic samples purchased from public markets in Tripoli, Libya in winter 2022: three brands each of Henna leaves, Henna paste, baby Talcum powder, and Khol stones. Khol stones carry the highest lead by an order of magnitude relative to the other three product categories: one sample reaches 102.1 µg/g, roughly 51× the BVL Germany cosmetic limit (2.0 µg/g), 10× the WHO/Health Canada limit (10 µg/g), and 200× the EU limit (0.5 µg/g). One Henna paste sample reaches 41.2 µg/g Pb; one baby Talcum powder sample reaches 33.6 µg/g Pb. Cd and tAs are present at lower but still appreciable levels in henna and kohl; Ni is largely below the limit of detection in henna and talc but reaches 1.5 µg/g in one kohl sample. The paper’s central argument is that international cosmetic heavy-metal guidelines diverge widely (FDA, EU 1223/2009, WHO, Health Canada, German BVL) and that the Libyan National Centre for Standardization and Metrology (LNCSM) lacks national specifications for cosmetic heavy-metal limits; the authors call for harmonization.

Key numbers

Per-sample concentrations from Table 3 (p. 5; µg/g; the ± column is reported as “±SD” in the table header but the paper text states “the percentage of RSD or (±cd) was calculated” so these values are interpreted as %RSD or RSD-derived dispersion estimates rather than absolute SDs — see Verification notes; ND = Not Detected):

Per-category ranges (computed from Table 3 by the wiki, not printed in the paper):

• Henna leaves (n=3): Pb 8.2–21.3 µg/g; tAs 0.8–1.7 µg/g; Ni ND–0.08 µg/g; Cd 0.04–0.8 µg/g.
• Henna paste (n=3): Pb 5.6–41.2 µg/g; tAs 1.4–3.5 µg/g; Ni ND–0.1 µg/g; Cd ND–1.7 µg/g.
• Baby Talcum powder (n=3): Pb 7.6–33.6 µg/g; tAs 0.8–2.2 µg/g; Ni ND–0.08 µg/g; Cd ND–0.8 µg/g.
• Khol stones (n=3): Pb 54.4–102.1 µg/g; tAs 1.4–4.5 µg/g; Ni 0.05–1.5 µg/g; Cd ND–1.2 µg/g.

Distribution-frequency ordering across all 12 samples (Results, p. 5): Pb > tAs > Cd > Ni.

Regulatory reference limits compared by the paper (Table 1, p. 3 — BVL Germany updated values; and Table 2, p. 3 — multi-jurisdiction comparison; µg/g unless noted):

Footnotes from the paper’s tables: ᵃ = “for the products make-up powder, rouge, eye shadow, eyeliner, Kajal, carnival make-up”; (C) = cosmetics; (CA) = color additives; “NK” = not known/not specified; ”**” = not specified in EU. Table 1 (BVL Germany) additionally lists Hg cosmetic limit 0.1 mg/kg and Sb 0.5 mg/kg, neither of which this study measured.

Exceedance counts that the paper reports narratively (Results, p. 5-6; numbers cross-checked by the wiki against Table 3):

• BVL Germany Pb (2.0 µg/g): all 12 samples exceed.
• WHO Pb (10 µg/g): 8 of 12 detected-and-exceed (LEAV1 21.3, LEAV3 11.9, PAS1 29.2, PAS3 41.2, BWD2 33.6, Koh1 54.4, Koh2 102.1, Koh3 89.8); 4 of 12 are below 10 (LEAV2 8.2, PAS2 5.6, BWD1 9.1, BWD3 7.6). The paper narrative on p. 6 states “samples containing high levels of Pd and passed the level of 10 ppm except for three samples” — this implies 9 above / 3 below, which under-counts the “below” by one. The Table 3 enumeration is taken as authoritative: 8 above, 4 below. See Verification notes for this narrative-vs-table discrepancy.
• Health Canada Pb (10 µg/g): same cut-off as WHO; 4 samples below 10, 8 above. Paper narrative p. 6 states “for Pd all the samples contained high levels of Pd, except four samples” — this row aligns to Table 3 (4 below).
• WHO tAs (3.0 µg/g): 3 samples exceed (PAS1 3.5, Koh1 3.4, Koh2 4.5).
• WHO Cd (0.3 µg/g): 3 samples are detected-and-below 0.3 (LEAV2 0.04, LEAV3 0.09, Koh1 0.07) and 4 samples are ND for Cd (PAS3, BWD1, BWD3, Koh3) — for a total of 7 of 12 samples at-or-below 0.3 µg/g. Paper narrative p. 6 states “only four samples are below the limit of 0.3 ppm.” The most plausible reading is that the paper’s “four below” refers to the 4 ND samples (treating ND as below-LOD-below-0.3), with the 3 detected-low samples treated as a separate category in the narrative; alternatively the narrative under-counts the at-or-below-0.3 set. Either way, Table 3 enumeration is authoritative: 3 detected-below + 4 ND = 7 at-or-below 0.3 µg/g; 5 above 0.3 µg/g (LEAV1 0.8, PAS1 1.7, PAS2 1.2, BWD2 0.8, Koh2 1.2). See Verification notes.
• WHO Ni (0.1 µg/g, paper text also writes 1.0 ppm — discrepancy with Table 2 which lists WHO Ni = 0.1): the paper narrative reports “only three samples are below the limit of 1.0 ppm of Ni” but Table 2 lists WHO Ni limit as 0.1 µg/g. At the 0.1 µg/g cut-off, two samples exceed (Koh2 0.2, Koh3 1.5); at the 1.0 µg/g cut-off, only Koh3 (1.5) exceeds. The narrative-versus-table discrepancy on the WHO Ni reference value is reproduced verbatim from the paper; see Verification notes.

Methods

Cosmetic products were purchased from different shops in Tripoli, Libya in winter 2022: three brands of talcum powder, Henna leaves and paste from various stockholders and distributors (Henna paste includes one locally produced homemade sample; the remaining Henna leaves, Henna paste, and Khol stones are predominantly imported from Sudan, India, and Pakistan). Henna leaf samples were dried at 85 °C in an air-ventilated oven for 12-24 hours, ground with a mixer grinder, and sieved through a 250 µm mesh.

For each sample, 1.0 g was weighed into Teflon vessels (to avoid metallic contamination) and digested with 6.0 mL of 65.0% nitric acid plus 2.0 mL of 30.0% hydrogen peroxide; the mixture was evaporated near dryness on a hot plate for 10 min, then filtered through Whatman No. 42 filter paper followed by 0.45 µm millipore filter paper, transferred quantitatively to a 50.0 mL volumetric flask, and topped up with deionized water. The 50.0 mL filtrate was transferred into an acid-rinsed polyethylene container for analysis. Glassware was cleaned with 6.0% nitric acid for 24 hours; Teflon beakers were treated with 6.0% nitric acid and washed with ultrapure water.

Quantification was performed on a Shimadzu AAS-6300 atomic absorption spectrophotometer at the Drug and Food Control Center laboratory (Tripoli). Standards were prepared from certified stock solution (1000 ppm, Merck, Darmstadt, Germany) and from Fluka Analytical (Sigma Aldrich, UK). Calibration concentration ranges: Pb 5.0–250 µg/mL; Ni 0.5, 1.5, 8 µg/mL; tAs 2.5, 10, 15, 20 µg/mL; other metals 0.5–60 ppm. Linear correlation coefficients (r²) were reported in the range 0.9822–1.000. The paper defines limit of detection (LOD) as the lowest calibration concentration for each metal and limit of quantification (LOQ) as 3 × LOD; specific per-metal LOD/LOQ values in finished-sample units (µg/g) are not enumerated. Recovery from spiked standard solutions across three concentrations was reported in the range “0.89%–99.5%” (printed verbatim; the 0.89% lower bound is anomalous and probably an 89% typo — see Verification notes). All solutions were prepared in double-distilled water; dilution correction was applied where samples were diluted or concentrated. Duplicate determinations per sample were averaged and the percentage of RSD (or ±cd) was calculated.

Speciation: total arsenic and total cadmium/lead/nickel only — no inorganic/organic As speciation, no inorganic Pb speciation, no Cr or Hg measurement. Mercury and antimony are listed as regulatory reference analytes (Table 1, BVL Germany updated limits) but not measured in this study.

Implications

• Certification (HMTc): Direct occurrence evidence for at least three HMTc Category 13 (Cosmetics and Personal Care — Leave-on) rows and one HMTc Cat 2 (Children Personal Care) routing destination. The three baby Talcum powder samples (BWD1-3) contribute occurrence data for baby-talcum-powder (Cat 2 children-personal-care routing) — Pb 7.6–33.6 µg/g, with BWD2 at 33.6 µg/g substantially exceeding the BVL Germany 2.0 µg/g cosmetic-Pb limit and meaningfully above the FDA 5.0 µg/g and WHO/Health Canada 10 µg/g caps. The three Khol stone samples (Koh1-3) contribute occurrence data for eye-makeup (Cat 13 Row 7) — Pb 54.4–102.1 µg/g, with the maximum at ≈ 51× the BVL Germany limit. The three Henna paste samples (PAS1-3) and three Henna leaves samples (LEAV1-3) contribute occurrence data for skin/body leave-on applications (henna paste applied to arms and thighs per the paper’s Introduction, p. 1) and for the leaves as the raw material that becomes paste or hair preparation. Sample frame is very small (n=3 per product category), method recovery range is wide, and the reported ±SD values are likely %RSD rather than absolute SD; these limitations make this source one contributing entry in a multi-source pool rather than a standalone anchor for any threshold.

• Courses: Useful as a teaching case for (a) the regulatory-divergence problem (FDA, EU, WHO, Health Canada, and German BVL diverge by 4-200× on the cosmetic Pb cap alone), (b) traditional cosmetic categories (henna, kohl) that fall outside most Western regulatory frameworks but carry the highest Pb concentrations, and (c) the limits of small-n AAS quality-control studies as a basis for population exposure inference.

• App: This paper is a leave-on cosmetic source (not food) and does not change any food-ingredient contamination_profile block. If the future Heavy Metal Index app extends to a leave-on personal-care category — particularly traditional cosmetics like kohl, henna, and ethnic baby talcum powders — the per-sample occurrence values from Table 3 are direct inputs.

• Microbiome: Not addressed by the paper.

Related evidence

• Lead
• Arsenic, Total
• Cadmium
• Nickel
• Baby Talcum Powder
• Eye makeup (liners, shadows, mascara, brow products, false lash adhesives, lash/eyebrow serums)
• Body/hand leave-on skin care
• Leave-on hair preparations (leave-in conditioners, tonics/dressings, styling aids, hair sprays, color sprays)

Update history

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