Content of Toxic Elements (Arsenic, Cadmium, Mercury, Lead) in Eggs from an Ethically Managed Laying Hen Farm

This study measured total arsenic, cadmium, total mercury, and lead separately in the yolk, albumen, and eggshell of 141 rural-farmed eggs from five hen genotypes and 60 organic supermarket eggs purchased in Italy. All analyses used ICP-MS with LOD 0.002 mg/kg and LOQ 0.005 mg/kg wet weight. The key finding is that supermarket eggs had significantly higher Pb in all matrices, while rural eggs had higher total arsenic in albumen and eggshell. Supermarket albumens showed detectable total mercury, while rural egg albumens were all below LOQ. Cadmium was below LOQ in all matrices for both egg groups. The authors note that no EU MRLs have been set for Pb, Hg, or Cd in eggs.

Key numbers

All values mg/kg wet weight, mean ± SD; LOQ = 0.005 mg/kg for all matrices.

Egg yolk:

• Rural (n=141): As = 0.011 ± 0.03 mg/kg; Cd = <LOQ; tHg = <LOQ; Pb = 0.089 ± 0.25 mg/kg (range by genotype: 0.023–0.141)
• Supermarket (n=60): As = 0.006 ± 0.01 mg/kg; Cd = <LOQ; tHg = <LOQ; Pb = 0.186 ± 0.04 mg/kg (all 5 supermarkets: 0.181–0.203)

Egg albumen:

• Rural: As = 0.112 ± 0.12 mg/kg; Cd = <LOQ; tHg = <LOQ; Pb = 0.039 ± 0.11 mg/kg
• Supermarket: As = 0.043 ± 0.06 mg/kg; Cd = <LOQ; tHg = 0.266 ± 1.65 mg/kg (highly variable; S2 = 1.077 ± 3.70, S3 = <LOQ); Pb = 0.688 ± 0.69 mg/kg

Eggshell:

• Rural: As = 0.202 ± 0.21 mg/kg; Cd = <LOQ; tHg = 0.006 ± 0.00 mg/kg (only 19/141 detectable); Pb = 0.022 ± 0.07 mg/kg
• Supermarket: As = 0.010 ± 0.00 mg/kg; Cd = <LOQ; tHg = 0.009 ± 0.00 mg/kg; Pb = 0.052 ± 0.20 mg/kg

Literature comparison table (Table 6) collects As, Cd, tHg, and Pb data from 20+ prior studies across Italy, Belgium, Bangladesh, Iran, Australia, Spain, USA, India, Pakistan, Greece, Taiwan, Brazil.

Methods (brief)

ICP-MS (Agilent 7700 series). Wet mineralization with concentrated nitric acid followed by dilution. LOD = 0.002 mg/kg; LOQ = 0.005 mg/kg for all matrices (wet weight). Isotopes monitored: Hg-202 and Pb-208 in He mode; As-75 in HeHe mode. CRM BCR-185R Bovine Liver used for accuracy verification. No arsenic speciation performed; total As reported. Mercury reported as total Hg without MeHg speciation. Statistical analysis: Kruskal-Wallis plus Dunn post-hoc (non-parametric), significance at p < 0.05.

Implications

Standards work: This paper provides egg-specific occurrence context for Pb, total arsenic, total mercury, and Cd across yolk, albumen, and eggshell matrices. It is useful for source-route context on eggs-product, especially because the authors explicitly note the absence of EU MRLs for Pb, Hg, and Cd in eggs. It should not be used to infer arsenic speciation or methylmercury.

Courses: Useful case study comparing rural ethical-farm eggs with commercial organic supermarket eggs. The five coded hen-genotype groups show different Pb and total-arsenic patterns across yolk, albumen, and eggshell.

App: Supports egg ingredient context, with clear labels for wet-weight units, matrix compartment, and the lack of arsenic or mercury speciation.

Microbiome: Not addressed in this study.

Wiki pages updated on ingest

• eggs
• eggs-product
• lead
• mercury-total
• arsenic-total

Verification notes

• Merge-enhanced 2026-05-18 from the full manual-fetch PDF path and SHA-256 recorded in frontmatter.
• DOI identity check matched the existing source page; no duplicate source page was found.
• Replaced the older manual-fetch-kimi handle, truncated raw path, empty product route, and generic arsenic/mercury wikilinks with current provenance and controlled routes.
• Corrected the supermarket albumen-Hg note: the 1.077 ± 3.70 mg/kg value is S2, not S1.
• Left matrices blank because the source’s measured compartments are egg yolk, albumen, and eggshell, and those matrix terms are not in the current controlled matrix list.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.