Overview
The author bought wheat, barley, sorghum and maize in Ambo’s local markets and measured nine metals by flame AAS after dry ashing. Table 2 gives one mean ± SD (three replicate analyses) per cereal on a dry-weight basis. Cadmium was not detected in any cereal.
Key numbers
- Lead: wheat 0.05 ± 0.03, barley 0.03 ± 0.06, sorghum 0.08 ± 0.05 mg/kg; not detected in maize (Table 2, p. 11).
- Cadmium: not detected in all four cereals (Table 2).
- Chromium: 0.29 (barley) to 0.95 mg/kg (sorghum) (Table 2).
Methods (brief)
Grain was oven-dried at 105 °C, ground, dry-ashed at 550 °C, dissolved in nitric and hydrochloric acids and read by flame AAS. Blanks were run, but no detection limits, reference materials or recoveries are reported.
Evidence Fitness
One value per cereal from replicate readings, with no count of market samples, no dates and no detection limits, so “not detected” cannot be bounded. Flame AAS is near its limit for lead at these levels. Maize iron and zinc are unusually low. Raw maize and wheat grain are ingredient proxies for corn-grits, corn-tortilla, cornbread, tortilla-chips, bran-cereal-with-raisins and toaster-pastry; those pages are not linked.