Overview
The authors measured lead, cadmium and zinc by flame AAS in 60 farm samples of six vegetables from Babol, northern Iran, and ran a Monte Carlo risk model for adults and children. Mean lead in every vegetable exceeded the cited FAO/WHO maximum levels, while cadmium exceeded only the bulb-vegetable level in onion. Arsenic and mercury were not measured.
Key numbers
- Lead (mg/kg dry weight, mean ± SE): peppermint 2 ± 0.25, dill 1.74 ± 0.26, spinach 1.68 ± 0.34, onion 1.39 ± 0.32, garlic 1.12 ± 0.18 (Table 2).
- Cadmium: spinach 0.08 ± 0.001, onion 0.06 ± 0.002, garlic 0.03 ± 0.005 mg/kg dry weight (Table 2).
- Mean of all vegetables: lead 1.55, cadmium 0.05, zinc 10.43 mg/kg dry weight (Table 2).
Methods (brief)
Washed edible parts were oven-dried at 80 °C, ground, digested on a hot plate in nitric, perchloric and sulfuric acids and analyzed by flame AAS. Method detection limits were 0.012 (lead) and 0.0028 (cadmium) mg/L in solution. Blanks and calibration checks were run; no certified reference material or recovery is reported.
Evidence Fitness
Farm samples from one district on a dry-weight basis, reported only as means with standard errors and without per-vegetable sample counts or a sampling year. Flame AAS lead results near 1 to 2 mg/kg without a reference material should be read with caution. The leafy herbs and spinach are a proxy for collard-greens, and the single-vegetable means are a proxy for vegetables-mixed; neither is measured.