Iyabo et al. 2015 — Zn, Cu, Cd, and Pb in staple foods consumed by Ekiti students

Iyabo and colleagues measured zinc, copper, cadmium, and lead in staple foods commonly consumed by university students in Ekiti State, southwest Nigeria. The foods were grouped as cereal/cereal products, legume products, and tuber products, with concentrations reported in mg/kg. The paper reports no arsenic, mercury, chromium, or nickel data.

Key numbers

Table 1 reports heavy metal concentrations in food items in mg/kg:

Detection limits printed below Table 1:

Table 2 reports average levels in mg/kg by food group:

Additional source-reported values:

• The text states overall Table 1 ranges as Zn 0.43-39.5, Cu 0.82-17.6, Cd LTDL-0.50, and Pb LDTL-0.30 mg/kg.
• Highest individual-item levels were Zn 39.5 mg/kg in wheat, Cu 17.6 mg/kg in groundnut, and Cd 0.50 mg/kg in rice with beans & fish.
• The paper states lead was significantly high in yam, Amala (yam and cassava flour), Garri (fried cassava), and potato; Table 1 lists several of those foods at Pb 0.30 mg/kg.
• Recommended permissible limits printed by the source were Zn 99.0 mg/kg, Cu 40.0 mg/kg, Pb 0.30 mg/kg, and Cd 0.20 mg/kg as set by FAO/WHO (2001).
• Percentage recoveries were Zn 92.2%, Cu 94.3%, Cd 96.0%, and Pb 98.2%.

Methods (brief)

A questionnaire was administered to 200 volunteered Ekiti State University students to identify commonly consumed staple foods. The identified foods were purchased from food vendors in the research locations, categorized into cereals, legumes, and tubers, air-dried for about 2-3 days, oven-dried at 105 °C for 24 h, and pulverized. One gram of each solid staple food was digested by dry ashing. Zinc, copper, lead, and cadmium were measured by atomic absorption spectrophotometer (AAS, Perkin Elmer Model 2130), and data were compared with FAO/WHO food-standard guideline values.

Implications

This source contributes Nigeria-market occurrence evidence for Zn, Cu, Cd, and Pb in prepared staple-food forms, including rice-containing mixed meals, wheat/noodle products, legume meals, peanut/groundnut, and tuber-based foods. The values are reported as food-item concentrations in mg/kg; the paper does not give a wet/dry basis beyond the stated sample drying protocol, so downstream normalization should preserve this uncertainty. Several entries are mixed meals rather than single ingredients and should be routed by product form rather than silently assigned to one ingredient.

Wiki pages this source may touch

• Rice
• Wheat
• Noodles
• Beans
• Peanuts
• Root vegetables
• Potatoes
• Yam
• Melon
• Mixed Meals, Rice-Containing
• Mixed Meals, Non-Rice
• Pasta (wheat-based)
• Other grain products (oat, millet, quinoa, barley)
• Legumes and Pulses, Other
• Peanuts
• Root and Tuber Vegetables
• Zinc
• Copper
• Cadmium
• Lead

Verification notes

• PDF text extracted with pdftotext -layout; Table 1 and Table 2 pages were also rendered from the PDF because several non-detect cells were visually crowded in the text layer.
• DOI verified from the first page as 10.5539/ijc.v7n1p155; DOI, raw-handle, and cite-key checks found no existing source page before creation.
• Table 1 values above were checked against the rendered page 157. Units are copied as mg/kg; no conversion was made.
• LT DL/LTDL is preserved as the source’s less-than-detection-limit label. Blank Cd cells for Sweet Beans (Red), Potato, and Fufu are recorded as not reported in table rather than filled.
• The source reports Zn, Cu, Cd, and Pb only. It does not report arsenic, mercury, chromium, nickel, inorganic arsenic, methylmercury, or Cr(VI).
• Frontmatter product and ingredient slugs were checked against docs/gpt-collaboration/taxonomy-snapshot.md; no new slug was invented.
• Audit 2026-06-09 (autonomous, Part 12 strict reading): the Table 1 rows “Indomine” and “Semovita”/“Semovita with soup” originally reproduced brand names attached to contamination values. Indomie (Dufil Prima Foods) is a registered instant-noodle brand; Semovita (Flour Mills of Nigeria) is a registered semolina brand. Rows relabeled to product-form descriptors “Instant noodles” and “Semolina porridge” / “Semolina porridge with soup”. Numerical values unchanged.
• Audit 2026-06-09: Table 2 Cu range for cereals corrected from “(1.30-12.20)” to “(1.30-12.2)”; the source’s run-together text “1.30-12.20.28±0.23” was parse-error transcribed into the wiki with the leading “0” of the next column’s Cd mean concatenated onto the Cu range upper bound.
• Audit 2026-06-09: Source page 158 prose attributes the Cu max (17.6) to “beans” and the Cd max (0.50) to “rice”. Table 1 maps Cu 17.6 to the “Groundnut” row (in the legumes section, where the paper grouped groundnut under “Legumes/Legumes product with others”) and Cd 0.50 to the “Rice with beans & fish” row. The wiki’s ## Key numbers bullet reports Table 1 row labels rather than the source’s prose words; the discrepancy is internal to the source.
• Audit 2026-06-09: Frontmatter ingredients: extended with yam and melon to reflect the Table 1 yam-based rows (Yam, Pounded Yam With Melon, Amala (Yam Flour), Yam With Oil, Yam With Egg) and melon-bearing rows (Melon, Eba With Melon, Pounded Yam With Melon).
• Audit 2026-06-09: Garri, Amala (Cassava Flour), Eba, and Fufu are cassava-derived foods, but cassava is not in the current docs/gpt-collaboration/taxonomy-snapshot.md ingredient list. Routing for these foods currently lands on [[ingredients/root-vegetables]] and [[products/root-tuber-vegetables]]. Flag for taxonomy maintenance: a cassava ingredient page (or cassava-flour/garri sub-slugs) may be warranted given how broad the West-African cassava-foods literature is.
• Audit 2026-06-09: matrices: [prepared-staple-foods, nigeria-market] uses descriptive bare strings that are not in the standard matrices controlled vocabulary. Retained pending matrices-vocabulary review rather than silently relabeled.

Page history

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