Manouchehri et al. 2021 — Heavy metals in honey: systematic review (Uludag Bee Journal)
This systematic review from Iranian and Turkish authors, published in the Turkish Uludag Bee Journal, evaluates the presence of toxic and carcinogenic heavy metals in honey, covering bee uptake pathways (contaminated water, pollen, nectar, inhalation during flight, adhesion to hairy body surfaces), the health effects of consuming contaminated honey, and findings from studies across multiple countries. Bees act as biomonitors for environmental heavy metal pollution, and honey from industrial areas consistently shows higher metal levels than honey from rural regions. Key geographic findings reviewed include: in Iran, most honey samples showed low contamination but Cd and Hg exceeded permitted limits in some regions tied to industrial proximity; in Croatia and Kosovo, Pb content was higher than reported in other European countries; in Nigeria, Fe, Cu, Mn, and Zn exceeded WHO/FAO permitted levels; studies in Turkey showed a direct correlation between honey metal contamination rates and proximity to industrial centres.
Key numbers
The review does not generate primary concentration data. Selected findings from cited studies reported in the review:
- Turkey/Iran: Cd and Hg above permitted limits in some honey samples from industrially proximate regions
- Nigeria: Fe, Cu, Mn, Zn mean concentrations above WHO/FAO MPL in honey
- A cited Croatian/Kosovo study: Pb in honey above reported values for other European countries
- One Iranian study (Saveh City, Markazi Province): Cd and As contamination measured in honey; values “similar to Turkey, Argentina, Nigeria, Pakistan”
- Several studies reported Cr, Zn, Fe, Ni, Mn, Pb, Cu, Cd, Co concentrations in honey below FAO/WHO limits, posing no risk (e.g., one multi-country study cited by Altekin et al. and Piven et al.)
Metals covered in the review: Fe, Zn, Cu, As, Pb, Cd, Ni, Cr, Al, Mn. Methods referenced in cited studies: ICP-OES, AAS.
Bee body accumulation is reported to be higher than honey accumulation for most metals, suggesting bees filter out some contamination in the honey production process.
Methods (brief)
Systematic review using keywords “heavy metals” and “honey” in databases: Google Scholar, SID, Scopus, PubMed, Science Direct, ISI. Received July 2021, accepted September 2021. No PRISMA protocol stated. Evidence tier B: the review is a useful synthesis of honey heavy metal literature across multiple countries but lacks primary occurrence measurements, does not present pooled quantitative estimates, and the Turkish-language journal has limited indexing depth. Useful as a gateway reference for the honey contamination profile and for its geographic survey of industrial-area effects on honey quality.
Implications
Certification: Honey is not a current HMT&C product category, but this review documents the contamination pathway through bee forage and establishes that honey quality is geographically variable, with industrial proximity a dominant driver. If honey certification is added, this review provides a literature orientation.
Courses: Useful for supply-chain modules demonstrating that biomonitors like bees reflect environmental contamination. Also illustrates the metal-in-packaging pathway: the review notes that acidic honey (pH ~3.9) can corrode metal containers, and soldered cans increase Pb and Sn in honey; unsealed or improperly coated storage containers are a contamination source.
App: Not a source of usable ppb values for contamination_profile. Storage container material is a relevant contamination lever for honey.