Overview
Abdelrahman and colleagues measured cobalt, cadmium and lead by ICP-OES in 150 raw milk samples from dromedary she-camels across five Saudi regions and three seasons, alongside camel and calf serum, soil, water and feed. Milk results are given in µg/L as regional and seasonal means (Table 5) and region-by-season means (Table 6). Lead in milk varied with region and season, peaking in Central region milk in spring.
Key numbers
- Lead, regional means: Western 0.543, Central 0.408, Eastern 0.315, Southern 0.269, Northern 0.128 µg/L (Table 5, p = 0.008).
- Lead, region by season: highest Central spring 0.966 µg/L, lowest Northern winter 0.126 µg/L (Table 6).
- Cadmium, regional means 0.046 to 0.076 µg/L (Table 5); region-by-season cells 0.028 to 0.194 µg/L (Western winter) (Table 6).
- Overall milk ranges printed as cadmium 0.03-0.19 µg/L and lead 0.13-0.97 µg/L (Section 3.3).
Methods (brief)
One mL of milk was digested on a hot plate with nitric acid, hydrochloric acid and hydrogen peroxide and read by ICP-OES (Thermo iCAP 7000) in duplicate. Instrumental LOD was 0.001-0.005 µg/L and LOQ 0.003-0.015 µg/L, stated for all elements together; values below the LOD were replaced with LOD/2. Quality control used NIST 1643f, a water reference material, with 92-106% recovery.
Evidence Fitness
Direct evidence for raw dromedary camel milk with a balanced design (10 animals per region per season) and the largest milk sample in this deposit. Two limits matter. First, the reference material is a water CRM, not a milk CRM, so recovery in the milk matrix is not demonstrated. Second, the Table 5 lead means do not equal the averages of the Table 6 lead cells (for example Central 0.408 µg/L versus cells 0.185, 0.296 and 0.966 µg/L); both tables are recorded as printed and every lead finding carries an integrity flag. Smaller mismatches of the same kind affect cobalt and cadmium. The sampling year is not stated. The authors compare µg/L results with the FAO/WHO (Codex) maximum levels of cadmium 0.05 mg/kg and lead 0.1 mg/kg without unit conversion.