Yorgwara et al. 2026 - heavy metals in personal-care products from Eleme, Nigeria

Yorgwara and colleagues measured Pb, Cd, total Cr, total As, total Hg, and Co in 26 cosmetic and personal-care products purchased from cosmetic stores and markets in Eleme LGA, Rivers State, Nigeria. The source groups the samples as facial cosmetics, skin/body-care cosmetics, and hair-care cosmetics, then reports concentration tables plus dermal-exposure calculations. The page preserves the source’s table units and total-metal speciation, while suppressing brand and product names attached to individual contamination values.

Key numbers

• Article identity: Research Journal of Pure Science and Technology 9(2):20-37; DOI 10.56201/rjpst.vol.9.no2.2026.pg20.37; received January 3, 2026; accepted February 15, 2026; published February 28, 2026.
• Sample frame: 26 finished cosmetic/personal-care samples from Eleme LGA, divided into 10 facial cosmetics, 8 skin/body-care cosmetics, and 8 hair-care cosmetics.
• Facial cosmetics, Table 4.1 (mg/g): Pb 0.15-1.26 mg/g; Cd 0.10-0.86 mg/g; total Cr 0.48-1.22 mg/g; total As 0.28-0.68 mg/g; total Hg 0.16-1.05 mg/g; Co 0.28-1.85 mg/g. The narrative says the maximum Cd was 0.89 mg/g, but the table’s highest Cd entry is 0.86 mg/g.
• Skin/body-care cosmetics, Table 4.2 (mg/L): Pb 0.20-1.43 mg/L; Cd 0.12-0.55 mg/L; total Cr 0.69-1.11 mg/L; total As 0.28-0.93 mg/L; total Hg 0.14-0.83 mg/L; Co 0.22-2.95 mg/L. The prose sometimes describes these values as mg/g, but the table header gives mg/L.
• Hair-care cosmetics, Table 4.3 (mg/L): Pb 0.12-1.19 mg/L; Cd 0.27-0.48 mg/L; total Cr 0.56-1.78 mg/L; total As 0.15-0.88 mg/L; total Hg 0.18-1.05 mg/L; Co 0.14-3.72 mg/L. The narrative says arsenic ranged to 0.58 mg/g, but the table includes a total-As value of 0.88 mg/L.
• Source-side comparator rows in Tables 4.1-4.3 list WHO, EU, Canada, and SON values for selected metals, including Pb 10, Cd 0.3, total Hg 1.0, and EU Pb 0.5, Cd 0.5, total Cr 1.0, total As 0.5. These are source-side comparators only, not HMTc thresholds.
• Chronic daily exposure, Table 4.4: maximum CDE values in the table were Pb 3.35E-09 mg/kg/d, Cd 2.01E-09 mg/kg/d, total Cr 4.17E-09 mg/kg/d, total As 6.68E-08 mg/kg/d, and total Hg 2.46E-09 mg/kg/d; Co is not included in the CDE table.
• Non-carcinogenic risk, Table 4.5: all reported metal HQ values were < 1, and total HI values ranged from 4.13E-05 to 2.31E-04 across the 26 samples. The Results prose states an HI range of 9.75E-05 to 2.31E-04, but the table contains lower HI values.
• Lifetime cancer risk, Table 4.6: Hg is listed as NIL; Pb, Cd, total Cr, total As, and Co values are all below the source’s 1 × 10-6 lower-bound risk comparator. The table’s highest Pb LCR is 3.94E-07; the prose separately says the highest cancer-risk value was 1.05E-07.
• Systemic exposure dosage, Table 4.7: skin/body-care products have the largest SED values in the table, including maxima of Pb 1875.9, Cd 1476.8, total Cr 4430.3, total As 1157.5, total Hg 1197.4, and Co 3791.7; facial cosmetics and hair-care cosmetics are generally lower in the same table.
• Margin of Safety, Table 4.8: facial lipstick rows show high MoS values for several metals, including Co values above 100, while many skin/body-care rows are in the 10^-6 to 10^-3 range. These are source-calculated risk metrics, not occurrence concentrations.
• ANOVA, Table 4.9: between-groups sum of squares 659.661, df 4, mean square 164.915; within-groups sum of squares 2791.071, df 57, mean square 48.966; F 3.368; Sig. .015.

Methods (brief)

The study collected 26 personal-care products from cosmetic stores and markets in Eleme LGA, Rivers State, Nigeria. The authors grouped them into facial cosmetics, skin/body-care cosmetics, and hair-care cosmetics; the source’s tables include eye pencils, lipsticks, eyeshadows, powders, foundation, soaps, perfumes, roll-ons, creams, hair foods, conditioners, shampoos, and hair dyes.

For digestion, the paper states that 5.0 g of each cosmetic sample was weighed into a conical flask, digested with an acid mixture described as 650ml conc HNO3: 80ml HClO4: 20ml conc H2SO4, heated to a clear solution, cooled, filtered through Whatman No. 1 filter paper, and diluted to 50 ml with distilled water. Heavy metals were determined by Agilent FS240AA atomic absorption spectrophotometry. Blanks and working standards are mentioned, but the paper does not report LOD/LOQ values, CRM recovery, spike recovery, replicate precision, or uncertainty intervals in the finished-product tables.

Speciation: Pb, Cd, Co, and total Cr are reported as elemental metals. The paper labels arsenic as As and mercury as Hg; this page treats them as total arsenic (tAs) and total mercury (tHg) because no inorganic-arsenic or methylmercury speciation is reported.

Implications

Certification (HMTc): This is direct finished-product occurrence evidence for adult personal-care products in the Nigerian market, but it is C-tier because of unit inconsistencies, limited QA/QC reporting, and source-side table/prose discrepancies. It can support occurrence context for eye makeup, face powders/foundations, body wash/soap-type products, fragrances, deodorants, leave-on creams, leave-on hair preparations, conditioners, shampoos, hair dyes, and lipstick, with the lipstick route currently limited by the retired adult-lipstick page.

Courses: The source is useful for teaching cosmetic-source routing, broad product categorization, and the brand firewall: the tables contain named products and brands, but the wiki keeps only category-level ranges and source-calculated risk summaries.

App: If adult personal-care profiles are expanded, the category ranges and risk-calculation caveats can support a Nigeria-market context card. The source should not be used to claim iAs, MeHg, or Cr(VI), and its source-calculated dermal risk metrics should remain separate from product-concentration occurrence values.

Wiki pages this source may touch

• lipstick
• eye-makeup
• makeup-foundation-powders-blush
• body-wash-shower-gel
• fragrance-preparations
• deodorants
• body-hand-leave-on-skin-care
• leave-on-hair-preparations
• conditioner-adult-rinse-out
• shampoo-adult
• hair-dye-rinse-off
• lead
• cadmium
• chromium
• arsenic-total
• mercury-total
• cobalt

Verification notes

• PDF text was extracted with pdftotext -layout to /tmp/mfk_june8_personal_care_heavy_metals_2026.txt. The title/byline, DOI block, abstract, methods, Tables 4.1-4.9, discussion, and conclusion were checked against this page.
• DOI 10.56201/rjpst.vol.9.no2.2026.pg20.37, title text, raw handle MFK_assessment-of-heavy-metal-concentration-in-some, raw SHA-256 1a048149a6857c697b3b3dcadee8b2a1845ae2fa8ed11305a03de3ff019c22a4, and candidate cite-key yorgwara2026-personal-care-metals-nigeria were searched before creation; no existing source page was found.
• Units are copied exactly from the source tables as mg/g for facial cosmetics and mg/L for skin/body-care and hair-care cosmetics. No conversion to ppm, mg/kg, or ppb was performed.
• Speciation: the paper reports As and Hg only; this page records them as total arsenic (tAs) and total mercury (tHg) and does not promote them to inorganic arsenic or methylmercury. The paper discusses chromium toxicity generally, but its analytical tables report total Cr, not Cr(VI).
• Source-side inconsistencies retained rather than corrected: Table 4.1 has a Cd maximum of 0.86 mg/g while the prose says 0.89 mg/g; Table 4.2 and Table 4.3 headers use mg/L while surrounding prose often says mg/g; the Table 4.3 total-As maximum is 0.88 mg/L while the prose says 0.58 mg/g; Table 4.5 contains HI values below the prose-stated minimum 9.75E-05; and Table 4.6 contains Pb LCR values higher than the prose-stated maximum 1.05E-07.
• Brand firewall: Tables 4.1-4.8 attach named products/brands to contamination and risk values. This page reports only product-category ranges and de-identified risk maxima; no consumer brand or shade/product name is attached to a contamination value.
• Evidence tier: C because the paper is peer-reviewed and contains primary occurrence tables, but the methods and reporting are weak for benchmark use: no sampling year, no LOD/LOQ, no CRM or recovery results, no replicate precision, no uncertainty, inconsistent units, and several table/prose discrepancies.
• Routing: all product slugs used in frontmatter appear in docs/gpt-collaboration/taxonomy-snapshot.md. Missing exact slugs: the snapshot has no non-retired adult lip-products slug, no adult bar-soap/bathing-soap slug, no facial-powder-only slug, and no explicit hair-food slug. This page uses broad available products (lipstick, body-wash-shower-gel, makeup-foundation-powders-blush, and leave-on-hair-preparations) rather than inventing new slugs.

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.