Overview
Habib and colleagues analyzed grain of 20 wheat varieties from a research center in Quetta for lead, chromium, zinc, nickel and copper by AAS. Each variety was analyzed in triplicate, and Table 2 gives the variety means. Cadmium and arsenic were not measured.
Key numbers
- Lead across varieties: 0.04 to 0.70 mg/kg, mean 0.25 mg/kg (SD 0.22) (Table 3, p. 293).
- Highest lead: 0.70 mg/kg in two varieties; lowest 0.04 to 0.05 mg/kg in three (Table 2, p. 292).
- Nickel mean 3.17 mg/kg and chromium mean 0.12 mg/kg (Table 3).
Methods (brief)
Grain was washed, oven-dried, ground and wet-digested with sulfuric acid and hydrogen peroxide, then read by AAS. No detection limits, reference materials or recoveries are reported.
Evidence Fitness
One grain lot per variety from a single research station, with no dates or quality control data. Results show variety differences for lead but come from a small set. Raw wheat grain is an ingredient proxy for bagel and toaster-pastry; those pages are not linked.