Overview
Altwaiq and colleagues measured lead, cadmium, nickel, copper and arsenic in single retail samples of cereals, legumes, breads, rice, canned tuna, processed meats and soft drinks from Amman, Jordan. Every sample was read by both ICP-AES and AAS, and the paper compares the two. Results are printed per sample in mg/L (ppm), including for solid foods.
Key numbers
- Diet cola (SD57): lead “0.08” (ICP-AES) and “0.09” (AAS) mg/L; cadmium “0.01” and “0.03” mg/L; nickel “0.02” and “0.35” mg/L (Table 14, p. 16).
- Regular cola (SD54): lead “0.08” (ICP-AES) vs “0.50” (AAS) mg/L, showing the method disagreement (Table 14).
- Rice arsenic: “0.03 + 0.01” to “1.16 + 0.05” mg/L by ICP-AES; the Sri Lankan samba rice is highest (Table 11, p. 15).
- Canned tuna lead: up to “0.52 + 0.05” (ICP-AES) and “0.7 + 0.08” (AAS) mg/L (Table 12, p. 16).
Methods (brief)
Solid foods were ground and digested on a hot plate in nitric acid (cereals and rice) or nitric and sulphuric acid (meat and tuna). Soft drinks (25 mL) were evaporated with nitric acid and made up to 50 mL. Digests were read by ICP-AES and by flame AAS (graphite furnace for arsenic). The paper gives LoD and LoQ for each method (Table 9) but no reference material or recovery.
Evidence Fitness
These are single samples with no QA beyond calibration. Many values sit below the stated LoQ, and some AAS values fall below the AAS LoD. The two methods often disagree widely, so both are recorded as printed. All units are mg/L, and the paper does not say whether that is per litre of digest or of food, so values are not converted. Sample codes conflict: the soft drink list has SD50 with no result, processed meat codes are duplicated and offset, and the abstract (57) and conclusion (seventy-five) give different totals. Peer review is unverified. The diet cola result is a direct measurement but is one sample.