Marcelino et al. 2026 — Liver trace minerals and heavy metals in free-living large herbivores, Netherlands
A twenty-year post-mortem monitoring programme at the Oostvaardersplassen (OVP) nature reserve in the Netherlands measured 13 trace elements and heavy metals by ICP-MS in the livers of 346 Heck cattle, red deer, and Konik horses, establishing species-specific reference intervals and documenting temporal trends in hepatic concentrations of Pb, Cd, As, Cr, Ni, Co, Cu, Fe, Mn, Mo, Se, V, and Zn across 2003–2023.
Key numbers
Total n = 346: Heck cattle 167, red deer 96, Konik horses 83. LOQ (mg/kg dry weight): As 0.4, Cd 0.1, Cr 0.1, Co 0.1, Cu 1, Fe 10, Pb 0.1, Mn 0.1, Mo 0.1, Ni 0.1, Se 0.4, V 0.1, Zn 5.
Reference intervals for “non-indicative of disease” animals (mg/kg dw, 95% RI):
Heck cattle (n=38 for RI): Cu 2.0–70.5; Fe 232.9–2,578.2; Pb not quantifiable–4.6; Mn 6.1–14.6; Mo 0.6–6.4; Se not quantifiable–1.2; Zn 43.1–383.7. As, Cd, Cr, Ni, V were below LOQ in >50% of samples.
Red deer (n=57 for RI) and Konik horses (n=53 for RI): reported in Tables 4 and 5 of the source. Horses showed elevated Fe and Pb relative to cattle; red deer showed comparatively higher Cu. Temporal declines in Fe and Pb were statistically significant across all three species (p < 0.01), with additional year-related declines in Co, Cu, and Zn in cattle, and Cr, V, and Zn in horses.
Methods (brief)
Post-mortem liver sampling from carcasses submitted for pathological examination 2003–2023. Approximately 100 g liver homogenized, dried at 103°C for dry weight, digested in 65% HNO3 by microwave, diluted with ultrapure water, internal standards added (Ge, Sc, Tl). ICP-MS (Agilent). ISO 17025-compliant laboratory. Dry-weight basis throughout. As and Ni were >50% below LOQ in horses; As, Cd, Cr, Ni, V were >50% below LOQ in cattle and red deer, so these elements were excluded from regression and RI analyses for those species.
Note on arsenic: the paper reports total As by ICP-MS without speciation; values should be treated as tAs, not iAs.
Implications
Certification: Heck cattle and red deer livers are sold as game or semi-wild meat products in Netherlands and broader EU markets. Pb concentrations (upper RI 4.6 mg/kg dw in cattle) and the temporal declining trend align with reduced environmental Pb inputs. Cd was detectable but majority of samples below LOQ (0.1 mg/kg dw). The study documents that livestock reference intervals do not apply directly to free-living herbivores, which is relevant to any certification program assessing game liver as a food matrix.
Courses: Illustrates environmental monitoring application of ICP-MS for long-term wildlife health and food-chain contamination trends.
App: Liver from free-ranging cattle and deer is a relevant food matrix for heavy metal occurrence; this study provides NL-specific baselines.