Overview
Uroko and colleagues measured nine metals by AAS in ten fruits from Ubani market in Umuahia, Nigeria, including tomato, cucumber, eggplant, watermelon, walnut and several local fruits, and estimated daily intake, hazard quotients and cancer risk. Table 1 gives mean ± SD (n=3) in ppm on oven-dried samples.
Key numbers
- Watermelon (Citrullus lanatus): cadmium 0.035±0.001 ppm, lead not detected, nickel 0.007±0.001 ppm (Table 1, p. 42).
- Cadmium ranged 0.033±0.002 ppm (cucumber) to 0.042±0.001 ppm (pepper fruit); lead was not detected in any fruit (Table 1).
- Chromium: 0.322±0.001 ppm in monkey kola; not detected in soursop (Table 1).
Methods (brief)
Washed, oven dried at 100 °C for 48 h, ground, digested with HNO3/HClO4 (5:1), diluted to 25 mL and read by AAS (Thermo AA 303) in triplicate. Calibration with single-element standards; no LOD, reference material or recovery reported.
Evidence Fitness
Triplicate readings of one purchase per fruit, without an LOD, so non-detects cannot be bounded. The text and abstract contradict Table 1 on which fruits lacked cobalt (the nickel column matches the text). The “permissible limits” in Table 1 (for example cadmium 0.001 ppm) have no stated source. Watermelon is a proxy for the cantaloupe page, which is not linked.