Overview
This study measured cadmium, chromium, copper and zinc in dry soya, white and red beans sold in three wards of Gamawa LGA, Nigeria, and calculated hazard indices. Soya beans had the highest values for all four metals and white beans the lowest. Lead, arsenic and mercury were not measured.
Key numbers
- Cadmium: soya beans 0.12, red beans 0.11, white beans 0.09 mg/kg dry weight (Table 1).
- Cadmium by ward ranged from 0.08 mg/kg (white beans, Alagarno) to 0.13 mg/kg (soya beans, Kafiromi) (Table 2).
- Zinc 22.40 to 25.60 mg/kg and copper 7.90 to 8.45 mg/kg across bean types (Table 1).
Methods (brief)
Beans were rinsed, dried at 70 °C, powdered and digested with a nitric, perchloric and sulfuric acid mix. The methods name both AAS and MP-AES, so the instrument behind the numbers is unclear. QA was triplicates, blanks and spike recoveries of 95 to 105%. No reference material was used and no detection limits are printed.
Evidence Fitness
Small study with single means and no SDs. Table 1 says n = 3 while the design implies 27 samples. The collection year is not stated. The reference list has many entries whose titles do not match the cited works, which lowers confidence. Only cadmium is a priority metal here. Dry market beans are a proxy for pinto-beans, pork-and-beans-canned and refried-beans, not those foods, so those pages are not linked.