Overview
Abdulrasheed and colleagues measured Mn, lead (Pb), chromium (Cr), cadmium (Cd), and nickel (Ni) in informally manufactured cookware from Saki, southwest Nigeria, along with moulding inputs and site soils. The paper is direct product evidence for metal-alloy cookware composition and supply-chain evidence for informal manufacturing inputs. Its leaching test found no detectable metals in boiled-water leachates, so the total cookware concentrations should not be treated as the amount transferred to food.
Key numbers
- Four cookware samples had mean metal concentrations of Mn 375 +/- 461 mg/kg, Cr 26.9 +/- 23.9 mg/kg, Cd 1.70 +/- 2.50 mg/kg, Pb 136 +/- 201 mg/kg, and Ni 181 +/- 265 mg/kg.
- Sample-level cookware Pb ranged from 18.4 +/- 0.9 to 439 +/- 12 mg/kg. Cd ranged from 0.30 +/- 0.01 to 5.45 +/- 0.15 mg/kg. Ni ranged from 33.3 +/- 1.5 to 578 +/- 18 mg/kg.
- The highest cookware sample also had Mn 1064 +/- 32 mg/kg, Cr 62.2 +/- 1.8 mg/kg, Cd 5.45 +/- 0.15 mg/kg, Pb 439 +/- 12 mg/kg, and Ni 578 +/- 18 mg/kg.
- In the neutral-water leaching test, 500 mL distilled water was boiled in cookware for 1, 2, and 3 h; Mn, Cr, Cd, Ni, and Pb were all below the analytical detection limit of 0.01 mg/L, so the paper did not tabulate leachate concentrations.
- Moulding materials showed a wide range of metals: battery material contained Mn 185,388 mg/kg, Cd 11.5 mg/kg, Pb 1004 mg/kg, and Ni 48.5 mg/kg. Clay, sand, ash, and charcoal had lower but detectable Pb values from 6.58 to 28.1 mg/kg.
- Manufacturing-site soils contained Mn 257-1306 mg/kg, Pb 10.7-177 mg/kg, Cr 30.0-95.0 mg/kg, Cd 0.0250-3.88 mg/kg, and Ni 9.90-58.0 mg/kg.
Methods (brief)
The authors clipped cookware fragments, air-dried and sieved soil and moulding materials, digested samples using US EPA Method 3050B, and analyzed Mn, Pb, Cr, Cd, and Ni by flame atomic absorption spectrophotometry. Leaching potential was tested by boiling distilled water in cookware for up to 3 h and analyzing cooled leachates by flame AAS. Chromium was measured as total chromium, not hexavalent chromium (Cr-VI).
Related evidence
- Metal and alloy cookware (cast iron, stainless steel, aluminum)
- Lead
- Cadmium
- Nickel
- Chromium
- Atomic absorption spectrometry (AAS)
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and 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.