Provisional scaffold. This page was created automatically on 2026-06-02 so that an ingested source could route to it. The HMTc taxonomy row, clean/contaminated pairing, primary metals of concern, and detailed scope have not yet been locked. Content below is minimal until a synthesis pass or taxonomy review consolidates the literature for this product class.
Reason: ingest of oviri2024-nigeria-bathing-soaps-metals declared bathing-soaps as the author-stated product class for Nigerian medicated, moisturizing, toilet, and skin-whitening soaps
Triggering source: Assessment of the concentrations and human exposure to heavy metals in bathing soaps in Nigeria
Literature scope
Reported measurements from source notes are below. Sections that are still empty have not been synthesized into a population estimate. HMTc certification thresholds for products in this row continue to be developed under the certification program at heavymetalcertified.com, not on this public page.
Reported measurements
Oviri, Tesi, and Emoyan report lead, nickel, zinc, cobalt, cadmium, and total chromium in 17 bathing soaps (five medicated, six moisturizing, three toilet, and three skin-whitening) in mg/kg of finished soap. Across the individual samples, lead was 0.08 to 0.28 mg/kg, cadmium 0.02 to 0.05 mg/kg, nickel 0.05 to 0.24 mg/kg, total chromium 0.01 to 0.09 mg/kg, cobalt 0.33 to 1.93 mg/kg, and zinc 0.10 to 6.42 mg/kg. The note does not report a limit of detection or a limit of quantitation, and it does not identify hexavalent chromium.
The same note prints category means beside those samples. Medicated soaps (n = 5): lead mean 0.108 mg/kg (median 0.10 mg/kg, 0.08 to 0.16 mg/kg), nickel mean 0.176 mg/kg (median 0.19 mg/kg, 0.12 to 0.22 mg/kg), zinc mean 0.488 mg/kg (median 0.40 mg/kg, 0.18 to 1.03 mg/kg), cobalt mean 0.836 mg/kg (median 0.56 mg/kg, 0.33 to 1.93 mg/kg), cadmium mean 0.032 mg/kg (median 0.03 mg/kg, 0.02 to 0.05 mg/kg), and chromium mean 0.048 mg/kg (median 0.04 mg/kg, 0.03 to 0.07 mg/kg). Moisturizing soaps (n = 6): lead mean 0.135 mg/kg (median 0.12 mg/kg, 0.10 to 0.21 mg/kg), nickel mean 0.204 mg/kg (median 0.20 mg/kg, 0.05 to 0.24 mg/kg), zinc mean 1.660 mg/kg (median 0.61 mg/kg, 0.10 to 6.42 mg/kg), cobalt mean 0.794 mg/kg (median 0.73 mg/kg, 0.59 to 1.01 mg/kg), cadmium mean 0.042 mg/kg (median 0.04 mg/kg, 0.02 to 0.05 mg/kg), and chromium mean 0.028 mg/kg (median 0.02 mg/kg, 0.01 to 0.07 mg/kg). The six moisturizing nickel samples in the same note are 0.19, 0.20, 0.24, 0.18, 0.09, and 0.05 mg/kg, beside the moisturizing nickel category mean of 0.204 mg/kg. The six moisturizing zinc samples are 6.42, 0.12, 0.10, 1.05, 0.73, and 0.63 mg/kg, beside the moisturizing zinc category mean of 1.660 mg/kg. This page repeats both and does not choose one. Toilet soaps (n = 3): lead mean 0.200 mg/kg (median 0.18 mg/kg, 0.14 to 0.28 mg/kg), nickel mean 0.177 mg/kg (median 0.19 mg/kg, 0.13 to 0.21 mg/kg), zinc mean 0.530 mg/kg (median 0.57 mg/kg, 0.41 to 0.61 mg/kg), cobalt mean 0.730 mg/kg (median 0.73 mg/kg, 0.66 to 0.80 mg/kg), cadmium mean 0.047 mg/kg (median 0.05 mg/kg, 0.04 to 0.05 mg/kg), and chromium mean 0.077 mg/kg (median 0.07 mg/kg, 0.07 to 0.09 mg/kg). Skin-whitening soaps (n = 3): lead mean 0.170 mg/kg (median 0.18 mg/kg, 0.12 to 0.21 mg/kg), nickel mean 0.143 mg/kg (median 0.11 mg/kg, 0.11 to 0.21 mg/kg), zinc mean 0.410 mg/kg (median 0.32 mg/kg, 0.30 to 0.61 mg/kg), cobalt mean 0.507 mg/kg (median 0.42 mg/kg, 0.37 to 0.73 mg/kg), cadmium mean 0.033 mg/kg (median 0.03 mg/kg, 0.02 to 0.05 mg/kg), and chromium mean 0.060 mg/kg (median 0.07 mg/kg, 0.04 to 0.07 mg/kg). Assessment of the concentrations and human exposure to heavy metals in bathing soaps in Nigeria
Alizadeh and colleagues report total lead and total mercury in 32 bar soaps, in µg/g of finished soap as purchased (mean ± SEM). Cosmetic soaps (n = 12): lead 0.10 ± 0.01 µg/g and total mercury 0.02 ± 0.004 µg/g. Hygiene soaps (n = 15): lead 0.19 ± 0.04 µg/g and total mercury 0.08 ± 0.013 µg/g. Contraband soaps (n = 5): lead 0.13 ± 0.04 µg/g and total mercury 0.23 ± 0.122 µg/g. The note says contraband mercury was higher than cosmetic mercury (P<0.01) and hygiene mercury (P<0.05), and that lead differences across the three categories were not statistically significant. The highest mean mercury in the note is 0.39 ± 0.320 µg/g for one contraband line, and the highest mean lead is 0.36 ± 0.205 µg/g for hygiene brand P. A within-hygiene contrast between brands P and T is printed at P<0.05. The prose describes that contrast as a lead contrast. The asterisk in Table 3 is printed on the mercury column. This page repeats both and does not choose one. The FDA comparators the source invokes are 1 µg/g for mercury and 20 µg/g for lead. Those are the authors’ comparators. The note does not report a numerical limit of detection or limit of quantitation. Mercury is total mercury. Mercury and Lead Levels in Common Soaps from Local Markets in Mashhad, Iran
Torres and colleagues report four solid bar soaps, in ug/g of finished product. Cadmium was below 0.015 ug/g and lead was below 0.5 ug/g on every sample, including the bar soaps. Bar soap J3: magnesium 50.9 ± 0.9 ug/g and zinc 448.9 ± 0.6 ug/g. Bar soap J4 (mixed skin): magnesium 66.1 ± 0.8 ug/g and zinc 537.5 ± 2.9 ug/g. Bar soap J7: magnesium 54.5 ± 1.7 ug/g and zinc 463.2 ± 2.0 ug/g. Antibacterial bar soap J8: magnesium 63.8 ± 1.3 ug/g and zinc 522.5 ± 7.9 ug/g. For bar soaps J3 and J4 the note also prints a microwave-reference pair beside the proposed method: J3 magnesium 50.9 ± 0.9 ug/g and 46.3 ± 0.1 ug/g, J3 zinc 448.9 ± 0.6 ug/g and 452.2 ± 1.4 ug/g, J4 magnesium 66.1 ± 0.8 ug/g and 64.0 ± 0.4 ug/g, J4 zinc 537.5 ± 2.9 ug/g and 553.5 ± 2.7 ug/g. The note says a paired test found the two methods were not significantly different for the detected analytes. Spike recoveries in the table ranged from 82.3 to 112 percent. The abstract summarises recovery as 83 to 119 percent. The conclusions state 79.0 to 118.6 percent. This page repeats all three and does not choose one. Powder detergent and liquid soaps in the same note are not bathing soap and are not repeated here. The authors cite Brazil ANVISA Resolution RDC No. 44/2012 comparators for minerals in artificial organic dyes used in soap manufacturing, including lead at 20 mg/L. That figure is the authors’ comparator for dye minerals, not a measured bar-soap concentration. Potentially Toxic Elements in Commercial Soap and Powder Detergent Samples
Iwegbue and colleagues report bar soaps (8 brands), in µg/g of finished product on an as-purchased basis (the note writes µg g⁻¹). Cadmium 0.6 to 2.2 µg/g, lead not detected to 15.5 µg/g, chromium not detected to 43.7 µg/g, copper 1.5 to 11.5 µg/g, cobalt 2.0 to 7.0 µg/g, nickel 3.0 to 11.5 µg/g, manganese not detected to 24.5 µg/g, zinc 9.0 to 675 µg/g, and iron 162 to 434 µg/g. The note says the highest chromium (43.7 µg/g), the highest zinc (675 µg/g), and the highest iron (434 µg/g) were in a bar soap. The same note prints a pooled maximum copper of 7.5 µg/g across all 27 brands, beside the bar-soap copper range of 1.5 to 11.5 µg/g. This page repeats both and does not choose one. The note does not identify hexavalent chromium. Powdered detergents, liquid dish-washing soaps, hand sanitizers, and creams in the same table are not bathing soap and are not repeated here. Risk of human exposure to metals in some household hygienic products in Nigeria
Almukainzi and colleagues report one bar soap, as mean ± SD in ppm (mg/kg) of the as-sold finished product. Aluminum 60.94 ± 86.12 ppm, chromium 66.10 ± 93.37 ppm, manganese 7.42 ± 10.48 ppm, iron 520.53 ± 735.81 ppm, cobalt 0.49 ± 0.69 ppm, nickel 42.36 ± 59.87 ppm, copper 143.62 ± 202.96 ppm, zinc 376.24 ± 532.05 ppm, total arsenic 1.52 ± 2.15 ppm, cadmium 0.45 ± 0.63 ppm, and lead 16.11 ± 22.78 ppm. The note says the standard deviation in nearly every cell sits at approximately the square root of 2 times the mean. This page repeats the printed means and standard deviations and does not replace them. Arsenic is total arsenic. A limit of detection and a limit of quantitation were not reported numerically. Mercury was not measured. Other product rows in the same table are not bar soap and are not repeated here. Quality and safety investigation of commonly used topical cosmetic preparations
Tjandraatmadja and colleagues report soap bars, in mg/kg of finished product. Selenium was detected in 4 of 6 brands: minimum 0.28 mg/kg, maximum 0.39 mg/kg, median 0.28 mg/kg, average 0.21 mg/kg, market-leader below 1.8 mg/kg, enviro-label 0.28 mg/kg, and private brand 0.33 mg/kg. The average of 0.21 mg/kg is printed beside the minimum of 0.28 mg/kg. This page repeats both and does not choose one. Chromium was below detection in all soap bar brands. The note does not print a soap-bar chromium concentration. Antimony was below the 5 µg/L detection limit in every soap brand. Sources of contaminants in domestic wastewater: nutrients and additional elements from household products
Bathing soap is a rinse-off skin product
Soap is applied to skin and rinsed. Gut studies of swallowed biomarkers, gavages, and occupational serum did not wash with this soap, and they do not describe the skin microbiota after a bath.
What remains uncertain
Hexavalent chromium gavage and occupational nickel are not soap concentrations. No stool or skin-microbiome study of this soap is cited.
References
Works cited in this page’s text, in first-appearance order. See Sources for this page’s source inventory. Each title links to a source record with bibliographic details, reported findings, and document provenance.
- Assessment of the concentrations and human exposure to heavy metals in bathing soaps in NigeriaPeer-reviewed
- Mercury and Lead Levels in Common Soaps from Local Markets in Mashhad, IranPeer-reviewed
- Potentially Toxic Elements in Commercial Soap and Powder Detergent SamplesPeer-reviewed
- Risk of human exposure to metals in some household hygienic products in NigeriaPeer-reviewed
- Quality and safety investigation of commonly used topical cosmetic preparationsPeer-reviewed
- Sources of contaminants in domestic wastewater: nutrients and additional elements from household productsIndustry
Sources
Source records associated with this topic. Inclusion does not establish that every finding applies to this product or ingredient. References above identify works cited in the text.
| # | Citation | Year | Type | Used on this page for |
|---|---|---|---|---|
| 1 | Oviri et al. 2024. Assessment of the concentrations and human exposure to heavy metals in bathing soaps in Nigeria, FUDMA Journal of Sciences 8(3 Special Issue): 422-430 | 2024 | Peer-reviewed | NG Pb, Ni, Zn, Co, Cd, Cr occurrence in Seventeen bathing soaps purchased from supermarkets in Abraka, Delta State, Nigeria: five medicated soaps, six moisturizing soaps, three… (n=17) |
| 2 | Torres et al. 2024. Potentially Toxic Elements in Commercial Soap and Powder Detergent Samples, Journal of the Brazilian Chemical Society 35(4): e-20230164, 1-10 (Sociedade Brasileira de Quimica) | 2024 | Peer-reviewed | BR Pb, Cd, Zn, Mg occurrence in Nine commercial cleaning products purchased in the metropolitan region of Recife, Pernambuco, Brazil: one powder detergent (J1), four… (n=9) |
| 3 | Iwegbue et al. 2019. Risk of human exposure to metals in some household hygienic products in Nigeria, Toxicology Reports 6 (2019) 914-923 (Elsevier; ISSN 2214-7500) | 2019 | Peer-reviewed | NG Cd, Pb, Cr, Cu, Co, Ni, Mn, Zn, Fe occurrence in Twenty-seven brands of household hygienic products purchased in Abraka, Sapele and Warri (Delta State, southern Nigeria), comprising ten… (n=27) |
| 4 | Alizadeh et al. 2017. Mercury and Lead Levels in Common Soaps from Local Markets in Mashhad, Iran, Iranian Journal of Toxicology | 2017 | Peer-reviewed | IR Pb, tHg occurrence in Common bar soaps purchased from Mashhad, Iran retail market in 2016: four anonymized cosmetic-soap brands (F, D, S,… (n=32) |
| 5 | Tjandraatmadja et al. 2010. Sources of contaminants in domestic wastewater: nutrients and additional elements from household products, CSIRO Water for a Healthy Country National Research Flagship Report (Smart Water Fund Round 3 — Project 5), February 2010 (ISSN 1835-095X) | 2010 | Industry | AU Sb, Cr, Co, Mo, Se occurrence in One hundred and fifty-six household and personal-care products purchased from major supermarkets in Melbourne, Australia between February and… (n=156) |
| 6 | Abulude et al. 2007. Assessment of the Content of Pb, Cd, Ni and Cr in Soaps and Detergents from Akure, Nigeria, Research Journal of Environmental Toxicology 1(2): 102-104 (Academic Journals Inc.; ISSN 1819-3420) | 2007 | Peer-reviewed | NG Pb, Cd, Ni, Cr occurrence in Nineteen soap and detergent samples purchased in Akure, Ondo State, Nigeria in July 2006. The sample mix as… (n=19) |
Update history
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