Rabeey et al. 2025 — Heavy metals in imported frozen bovine tissues, Sohag, Egypt
A 2025 peer-reviewed study analyzed 315 imported frozen bovine samples (105 each of muscle, liver, and kidney) from local markets in Sohag, Egypt for total mercury (tHg), lead (Pb), and cadmium (Cd) by atomic absorption spectrophotometry, finding that more than half of muscle and liver samples exceeded international maximum permissible limits (MPLs) for Hg and Pb. Despite widespread exceedance of regulatory thresholds, calculated health risk indices (THQ, cancer risk) remained below the level of concern for average Egyptian consumers at reported ingestion rates. The findings underscore a significant disconnect between regulatory threshold exceedance and formal risk-index estimates, and highlight the importance of ongoing heavy metal surveillance in imported frozen meat products.
Key numbers
All concentrations reported as mg/kg wet weight (equivalent to ppm wet weight; 1 mg/kg = 1,000 ppb).
Mercury (tHg):
- Muscle: range 0.013–1.228 mg/kg; mean ± SE = 0.312 ± 0.034 mg/kg; 54.3% (57/105) exceeded MPL of 0.05 mg/kg (USDA 2023)
- Liver: range 0.001–1.190 mg/kg; mean ± SE = 0.273 ± 0.031 mg/kg; 57.1% (60/105) exceeded MPL
- Kidney: range 0.001–0.790 mg/kg; mean ± SE = 0.167 ± 0.023 mg/kg; 40% (42/105) exceeded MPL
Lead (Pb):
- Muscle: range 0.020–1.999 mg/kg; mean ± SE = 0.684 ± 0.06 mg/kg; 62.9% (66/105) exceeded MPL of 0.1 mg/kg (EC 2015)
- Liver: range 0.006–1.841 mg/kg; mean ± SE = 0.763 ± 0.061 mg/kg; 60% (63/105) exceeded MPL of 0.5 mg/kg (EC 2015)
- Kidney: range 0.003–2.050 mg/kg; mean ± SE = 0.716 ± 0.068 mg/kg; 54.3% (57/105) exceeded MPL of 0.5 mg/kg (EC 2015)
Cadmium (Cd):
- Muscle: range 0.007–0.100 mg/kg; mean ± SE = 0.030 ± 0.003 mg/kg; 22.9% (24/105) exceeded MPL of 0.05 mg/kg (EC 2014)
- Liver: range 0.010–0.390 mg/kg; mean ± SE = 0.056 ± 0.008 mg/kg; 0% exceeded MPL of 0.5 mg/kg (EC 2014)
- Kidney: range 0.011–0.211 mg/kg; mean ± SE = 0.073 ± 0.004 mg/kg; 0% exceeded MPL of 1.0 mg/kg (EC 2014)
Health risk estimates (muscle and liver only; kidney excluded due to lower exceedance rates and per capita consumption):
- EDI as % of PTDI/BMDL: Hg 13.75% (muscle), 4.05% (liver); Pb 11.01% (muscle), 4.135% (liver); Cd 0.366% (muscle), 0.3% (liver)
- THQ: Hg 0.316 (muscle), 0.0928 (liver); Pb 0.433 (muscle), 0.1625 (liver); Cd 0.00304 (muscle), 0.00248 (liver)
- TTHQ: 0.752 (muscle), 0.257 (liver) — both below 1.0, indicating no non-carcinogenic concern at the reported ingestion rates
- Cancer risk (CR) for Pb and Cd: all values between E-7 and E-6, within acceptable range (below E-4 threshold)
Methods (brief)
Samples digested in concentrated nitric-perchloric acid (2:1) overnight at 55°C, filtered, and analyzed by atomic absorption spectrophotometry (Buck Scientific 210 VGP AAS). Mercury determined by cold vapor technique (MHS); Pb and Cd by air-acetylene flame. Wavelengths: 253.65 nm (Hg), 283.31 nm (Pb), 228.80 nm (Cd). Validation: R² = 0.999 for all calibration curves; spike recoveries of 96.4% (Hg), 98.9% (Pb), 95.9% (Cd) in fish tissue reference material (dogfish liver DOLT-4). Basis: wet weight. Speciation note: mercury reported as total mercury (tHg); the paper does not speciate inorganic vs. methylmercury. This paper reports tHg, not MeHg; tHg and MeHg must not be conflated in synthesis. Ingestion rates for risk assessment: muscle 7.1 g/day per 70 kg adult; liver 2.39 g/day per 70 kg adult (USDA 2022/2020 references for Egyptian consumers).
Implications
Certification: Pb and Hg levels in over half of imported frozen bovine muscle and liver samples exceed EU and USDA MPLs. This is direct evidence that imported beef from Brazil, India, and the USA entering the Egyptian market carries contamination levels relevant to certification thresholds. For HMT&C, note that the relevant matrix is bovine muscle and organ meats; the MPL frameworks are EU Commission Regulations 1005/2015 (Pb) and 488/2014 (Cd). The high exceedance rates (62.9% for Pb in muscle) make this a high-priority source for the beef products page.
Courses: Illustrates why country-of-origin and supply-chain provenance matter for heavy metal risk. Demonstrates the gap between formal risk index values below 1 (no concern at average daily intake) and widespread MPL exceedance, which is a useful teaching case for distinguishing regulatory exceedance from health risk assessment.
App: Bovine muscle mean tHg: 312 ppb wet weight (0.312 mg/kg); mean Pb: 684 ppb; mean Cd: 30 ppb. These are market-specific values from imported product in Egypt. App should note geographic and supply-chain context; these values likely exceed what would be measured in US or EU domestic markets.