Aljedani 2017 — Heavy metals and elements in honeybees and honey from Saudi Arabia
Honeybee (Apis mellifera jemenatica) bodies and honey samples were collected from four agricultural regions of Saudi Arabia and analyzed for eight heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) and four mineral elements (Ca, K, Mg, Na) by ICP-OES. In honeybee samples, Cd, Cr, Ni, and Pb were not detected (all ND, mean ± SD = 0.000 ± 0.000 mg/g) in any region; Fe was the dominant heavy metal (range 2.088–8.794 mg/g across regions). In honey samples, Cd, Mn, and Pb were not detected; Cr and Ni were found only in trace amounts in Al-Baha honey (Cr 0.1599 mg/L, Ni 0.037 mg/L); Fe was again the most concentrated metal (0.907–1.904 mg/L). All measured values fell within internationally permissible limits according to the authors, providing a relatively clean baseline for honey from agricultural regions distant from heavy industry.
Key numbers
Honeybee tissue concentrations (mg/g, mean ± SD, n = 3 per region):
| Metal | Jazan | Asir | Al-Baha | Makkah |
|---|---|---|---|---|
| Cd | ND | ND | ND | ND |
| Cr | ND | ND | ND | ND |
| Cu | 0.109 ± 0.000 | 0.268 ± 0.004 | 0.159 ± 0.001 | 0.253 ± 0.002 |
| Fe | 6.205 ± 0.009 | 6.222 ± 0.056 | 2.088 ± 0.009 | 8.794 ± 0.027 |
| Mn | 1.385 ± 0.002 | 1.714 ± 0.021 | 0.248 ± 0.001 | 2.067 ± 0.018 |
| Ni | ND | ND | ND | ND |
| Pb | ND | ND | ND | ND |
| Zn | 1.272 ± 0.002 | 1.179 ± 0.013 | 0.503 ± 0.002 | 1.038 ± 0.006 |
Honey concentrations (mg/L, mean ± SD, n = 3 per region):
| Metal | Jazan | Asir | Al-Baha | Makkah |
|---|---|---|---|---|
| Cd | ND | ND | ND | ND |
| Cr | ND | ND | 0.1599 ± 0.000 | ND |
| Cu | 0.039 ± 0.001 | ND | 0.159 ± 0.000 | 0.013 ± 0.001 |
| Fe | 1.843 ± 0.007 | 1.904 ± 0.009 | 1.341 ± 0.005 | 0.907 ± 0.001 |
| Mn | ND | ND | ND | ND |
| Ni | ND | ND | 0.037 ± 0.001 | ND |
| Pb | ND | ND | ND | ND |
| Zn | 0.077 ± 0.001 | 0.101 ± 0.001 | 0.056 ± 0.001 | 0.030 ± 0.000 |
Potassium was the most abundant mineral element in all honey regions (K range 5.590–35.873 mg/L). Calcium second-highest in honey (4.079–8.284 mg/L).
Note: The paper uses mg/g for honeybee tissue and mg/L for honey. Units are as reported by the authors; no wet-weight/dry-weight conversion is stated, and the paper does not address whether honey concentrations represent as-purchased or as-prepared.
Methods (brief)
Samples collected directly from hives in March 2017; 50 mg/g of bees and 20 mg/L of honey per region. Ash calcination method: samples burned to ash, calcined 13 hr at 450 °C in furnace, residual ash dissolved in 10 mL 0.5 M HNO3, filtered, analyzed by ICP-OES (Varian 720-ES). Method accuracy verified against certified reference material NIST-SRM 1515 Apple Leaves and INCY-TL-1 tea leaves. Three replicates per sample. No speciation reported; all values are total metal. The absence of Cd and Pb in honey (both reported as ND) should be interpreted cautiously given the relatively high LOD potential of the ash-calcination method, which can cause volatilization losses for Cd and Hg at 450 °C.
Implications
Certification: Values within permissible limits under 2017 Codex and EU standards. Fe dominance in both bee bodies and honey reflects use of iron tools in beekeeping operations per the authors’ attribution. The contrast with the Ethiopian and US papers in this batch is informative: Saudi agricultural honey from non-industrial regions shows very low Pb and Cd, supporting the conclusion that geographic contamination context drives honey metal burden more than intrinsic bee biology.
Courses: The dual-matrix approach (honeybee tissue plus honey) is useful for teaching the distinction between exposure biomarker (bee body burden) and product contamination (honey as consumed). The finding that Pb was ND in both matrices in all Saudi regions illustrates how honey can serve as a geographic proxy for environmental lead.
App: The ND values for Pb, Cd, Mn, and Ni in honey from these Saudi agricultural regions represent a low-contamination baseline scenario. Because detection method (ash calcination at 450 °C) may underreport volatile metals including Cd, these NDs should not be treated as confirmed absences; they are below-detection findings with a caveat on method sensitivity.