Kamaly & Sharkawy 2023 — Heavy metals in chicken meat and liver, Assiut, Egypt
This study measured 12 metals (Al, Cd, Pb, Ba, Bi, Co, Ni, Cr, Fe, Cu, Zn, Se) in 360 samples of broiler chicken chest muscle, thigh muscle, and liver sourced from six commercial brands in Assiut province, Egypt. ICP-MS analysis was performed at the central laboratory of Assiut University. Toxicologically significant findings include: Pb exceeded FAO/WHO permissible limits in 94% of all samples (240 muscle and 100 liver samples) and Egyptian Organization for Standardization (EOS) limits in 33% of chest muscle samples; Cd exceeded FAO/WHO limits in 17% of samples (40 muscles and 20 livers). Despite these exceedances, target hazard quotients and hazard indices for all metals remained below 1.0, and calculated target cancer risks were within acceptable ranges at the consumption rates modelled (39.53 g/day muscle; 0.1 g/day liver for Egyptian adults at 70 kg body weight). Al was the most highly concentrated metal measured, with chest muscle ranging 8.610–21.985 µg/g across brands.
Key numbers
Pb (µg/g wet weight, mean±SE by brand across chest/thigh/liver; ranges derived from Table 1):
- Chest muscles: 2.560–5.552 µg/g (all 6 brands); 94% exceeded FAO/WHO limit of 0.1 µg/g; 33% exceeded EOS limit of 1.0 µg/g
- Thigh muscles: 0.334–1.082 µg/g
- Liver: 0.146–0.952 µg/g
Cd (µg/g wet weight):
- Chest muscles: 0.014–0.054 µg/g
- Thigh muscles: 0.015–0.088 µg/g
- Liver: 0.027–0.104 µg/g
- 17% of samples (60 total) exceeded FAO/WHO limit of 0.05 mg/kg (muscle) / 0.5 mg/kg (liver)
- All samples below EOS guideline limit of 0.5 mg/kg
Al (µg/g wet weight):
- Chest muscles: 8.610–21.985 µg/g
- Thigh muscles: 5.729–18.533 µg/g
- Liver: 5.873–14.005 µg/g
- No established Egyptian or international permissible limit for Al in poultry edibles; all below WHO RDA of 60 mg/day
Ni (µg/g wet weight):
- Chest muscles: 0.154–0.228 µg/g
- Thigh muscles: 0.143–0.255 µg/g
- Liver: 0.112–0.217 µg/g
- FNB limit 4 mg/kg; EOS guideline 10 mg/kg; all well below limits
Cr (total; µg/g wet weight):
- Chest muscles: 0.266–2.215 µg/g
- Thigh muscles: 0.170–0.460 µg/g
- Liver: 0.161–1.422 µg/g
- Authors note total Cr, not speciated; WHO/FAO limit 1 mg/kg; most samples below limit
Analytical recovery rates: Al 97.3%, Cd 99.6%, Pb 93.6%, Ni 105.6%, Cr 104.9%.
Methods (brief)
ICP-MS (iCAP 6000 series, Thermo Scientific) after overnight nitric acid digestion at room temperature followed by heating at 150°C for 5 hours. Samples: 1 g tissue in 5 mL concentrated HNO3 (68%, Merck). Blanks and duplicates run in each batch; spiked recovery verified at 10-sample intervals. Results expressed in µg/g wet weight. No LOD/LOQ reported explicitly.
Speciation note: Cr reported as total chromium. Paper does not speciate Cr-III vs Cr-VI; the toxicological relevance differs substantially. The carcinogen concern (IARC Group 1) applies to Cr-VI; total Cr values cannot be equated to Cr-VI.
Limitation: Single urban market location (Assiut, Upper Egypt); 6 specific commercial brands; results may not generalize nationally. No information on feeding practices, age of birds, or origin of feed.
Implications
Certification: Pb findings are striking — 94% exceedance of FAO/WHO limits in muscle tissue at concentrations ranging 0.334–5.552 µg/g across tissues. These are approximately 3–55x the FAO/WHO poultry muscle limit of 0.1 µg/g. Al concentrations in the range of 8–22 µg/g in chest muscle are above the 3–5 µg/g range typical of poultry in European studies, suggesting feed or environmental contamination specific to this region. Context for HMT&C poultry/meat product categories and for any product containing chicken as a primary ingredient.
Courses: Illustrates how regulatory exceedances (especially Pb) can occur at concentrations where deterministic risk assessment models still yield HQ<1 due to conservative body-weight-to-consumption assumptions; demonstrates the gap between percentage-exceedance framing and HQ risk framing.
App: Al and Pb values in Egyptian commercial broiler are outlier-high relative to European norms; geographic sourcing should be flagged in any chicken-containing product risk model.