Khatemeh & Imani Baran 2022 — Pb, Cd, Cr in sheep liver and liver flukes from Iranian abattoir
Khatemeh and Imani Baran measured lead, chromium, cadmium, and copper concentrations in liver flukes (Fasciola hepatica and Dicrocoelium dendriticum) and in sheep liver tissue collected from an industrial abattoir in Tabriz, East Azerbaijan Province, Iran. The primary aim was to evaluate whether the two trematode species could serve as bioindicators of environmental heavy metal contamination. Key finding: Pb and Cr were significantly higher in F. hepatica than in either D. dendriticum or the infected host liver, with F. hepatica bioconcentration factors (BCFs) of 5.06 ± 1.04 for Pb and 17.27 ± 6.35 for Cr. From a food-safety perspective, the paper reports measured concentrations of Pb, Cd, and Cr in the edible sheep liver matrix (both infected and uninfected), providing a baseline for these metals in a commonly consumed ruminant organ meat from an Iranian industrial region.
Key numbers
All values in µg/g wet weight (mean ± SEM), as reported in Table 1 of the source.
Uninfected sheep liver:
- Pb: 0.12 ± 0.00 µg/g WW
- Cr: 0.40 ± 0.04 µg/g WW
- Cd: 0.07 ± 0.01 µg/g WW
- Cu: 2.92 ± 0.34 µg/g WW
F. hepatica-infected sheep liver:
- Pb: 0.10 ± 0.01 µg/g WW
- Cr: 0.11 ± 0.04 µg/g WW
- Cd: 0.11 ± 0.00 µg/g WW
D. dendriticum-infected sheep liver:
- Pb: 0.19 ± 0.05 µg/g WW
- Cr: 0.24 ± 0.01 µg/g WW
- Cd: 0.08 ± 0.00 µg/g WW
F. hepatica parasite tissue: Pb 0.43 ± 0.04, Cr 0.62 ± 0.08, Cd 0.08 ± 0.01 µg/g WW D. dendriticum parasite tissue: Pb 0.14 ± 0.01, Cr 0.59 ± 0.03, Cd 0.09 ± 0.00 µg/g WW
Bioconcentration factors (BCF) for F. hepatica relative to infected host liver:
- Pb BCF: 5.06 ± 1.04
- Cr BCF: 17.27 ± 6.35
- Cd BCF: 0.76 ± 0.08 (below 1; F. hepatica not a useful Cd bioindicator)
Analytical method: flame atomic absorption spectrometry (FAAS); wet-weight basis; n = 10 per group.
Methods (brief)
Adult F. hepatica and D. dendriticum collected from infected sheep livers at Tabriz industrial abattoir (December 2019 – February 2020). Ten samples per group (two parasite species, two infected-liver groups, one uninfected-liver group). Samples washed in PBS, stored at -26°C. Dried and incinerated at 600°C for 4 h; dissolved in 60% HNO₃. Flame AAS (novAA 800, Analytik Jena). Statistical analysis by Kruskal-Wallis and Mann-Whitney tests (SPSS 21.0). Limitation: Cu is an essential element, not a toxic heavy metal of primary food-safety concern; Cu data not included in the key numbers above. Cr speciation (total Cr vs Cr-VI) not performed.
Implications
Certification: Provides Pb, Cd, and Cr wet-weight concentrations in sheep liver from an Iranian abattoir. Values are below typical EU maximum levels for sheep liver (EU ML for Cd in liver is 0.5 mg/kg WW), though the contamination from F. hepatica infection appears to modestly alter metal distribution. Cr reported as total Cr; Cr-VI not speciated.
Courses: Illustrates the parasite-as-bioindicator concept and how liver flukes can bioconcentrate certain metals (Pb, Cr) far above host tissue levels. Also demonstrates that not all metals follow the same pattern (Cd BCF < 1 in F. hepatica).
App: Sheep liver Pb and Cd baseline from this paper (uninfected liver: Pb 0.12, Cd 0.07 µg/g WW) can contribute to the offal/organ-meat ingredient profile for Iranian-region sheep, with the caveat that n=10 uninfected livers is a small sample.