Overview
The authors bought sliced watermelon from six vendors in each of three Akure markets and measured nickel, chromium, copper, cadmium and lead by atomic absorption, comparing them with a whole fruit cut in the laboratory. Cadmium and lead were not detected in any sample. Nickel and chromium were higher in many vendor samples than in the control, which the authors link to handling and exposure during sale.
Key numbers
- Cadmium and lead: “0.00 ± 0.00” mg/kg in all vendor samples and the control (Tables 1-3).
- Nickel: 0.20 ± 0.01 (Isinkan, vendor D) to 1.42 ± 0.02 mg/kg (Oja-Oba, vendor C) (Tables 1 and 3).
- Chromium: up to 0.23 ± 0.01 mg/kg (Shasha, vendor F), not detected in the control (Table 2).
Methods (brief)
Fruit was blended, and 30 mL aliquots were digested with nitric acid and then aqua regia on a hotplate, then read by flame AAS. Quality control was limited to reagent blanks; no reference material, recovery or detection limit is reported.
Evidence Fitness
A small market snapshot (54 samples, one city) with weak analytical QA and no detection limits, so the cadmium and lead non-detects cannot be bounded. It is direct evidence for watermelon as a non-apple fruit. For cantaloupe it is only a related melon proxy and that page is not linked.