Overview
Lanre-Iyanda and Adekunle bought melon-seed cake (robo) and groundnut cake (kulikuli) from roadside vendors at seven motor parks in Abeokuta, Nigeria, and compared them with cakes taken directly from production centers. They measured cadmium, copper, lead, zinc, nickel and arsenic by flame AAS and estimated adult daily intakes. Lead was the dominant contaminant, and motor-park samples were higher than the controls for most metals, which the authors attribute to traffic-related atmospheric contamination of uncovered products.
Key numbers
- Groundnut cake, pooled seven parks (n = 147): lead “24.5± 9.3” mg/kg, range 15.03 to 33.13 (Table 3).
- Melon cake, pooled seven parks (n = 147): lead “16.3± 3.1” mg/kg, cadmium “0.04 ± 0.01” mg/kg, arsenic “0.62± 0.36” mg/kg (Table 3).
- Highest site mean: groundnut cake at Adatan, lead “40.63+7.25” mg/kg (Table 2).
- Production-center controls: melon cake lead “10.23 +0.35”, groundnut cake lead “10.52+ 1.28” mg/kg; arsenic not detected in either control (Tables 1 and 2).
Methods (brief)
Samples were oven-dried at 105 °C, ground, dry-ashed at 450 °C for 12 hours and digested in 5M nitric acid, then read by flame AAS. Quality control was limited to reagent blanks and acid-washed glassware; no certified reference material, recovery or detection limit is reported. The tables do not state the basis, but the drying step suggests dry weight.
Evidence Fitness
A large repeated market sample (21 per site per product) with means and SDs, but weak analytical QA and lead values far above typical food levels for flame AAS work. Table 3 has internal inconsistencies (melon cake copper mean below its own range; melon cake nickel range narrower than the site means). These are snack cakes made from melon seed and groundnut, a proxy for the doughnut page and not a doughnut measurement; no DOI is printed in the PDF.