Overview
Shuaibu and colleagues bought onion, spinach, lettuce, cucumber and pineapple from the same vendors at Kaura Namoda central market in Zamfara State, Nigeria, once per quarter from December 2024 to September 2025, and measured lead, chromium, cadmium, nickel, copper and cobalt by flame AAS. Levels were highest in the December (dry-season) quarter and lowest in the June (rainy-season) quarter. Lead stayed at or below 0.21 mg/kg dry in all samples.
Key numbers
- Cucumber lead 0.18 ± 0.001 mg/kg dry in Q1 and cadmium 0.46 ± 0.004 mg/kg in Q1 (Table I, p. 24).
- Spinach lead 0.08 ± 0.004 mg/kg in Q1 and 0.05 ± 0.004 in Q4 (Table I).
- Onion cadmium 0.335 ± 0.032 mg/kg in Q3; pineapple lead 0.207 ± 0.001 mg/kg in Q4 (Table I).
Methods (brief)
Edible parts washed, peeled and oven-dried, ground, digested in hydrochloric and nitric acid (3:1) at 120 C for 5 hours, then analysed by AAS in triplicate. Results are mean ± SD on a dry basis. Detection limits, reference materials and recoveries are not reported; the number of units per purchase is not stated.
Evidence Fitness
A single vendor and one purchase per quarter, so the SDs reflect analytical replication only. The abstract and text contradict Table I in several places (recorded as printed). For vegetables-mixed this is a proxy (individual vegetables, no mixed product). Zamfara State has a history of lead poisoning linked to artisanal mining, but the produce origin is not stated.