Żarski et al. 2017 - Mercury in mallard tissues from Poland

Żarski and colleagues measured mercury in liver, kidney, and muscle tissues from adult mallards collected at Włocławek Reservoir in Poland. The study is routeable for game-bird and organ-meat mercury context because it reports tissue concentrations and identifies muscle as the lowest-concentration tissue. It does not speciate mercury as methylmercury.

Key numbers

• Sample: 30 adult mallards (Anas platyrhynchos), 2013/2014 autumn hunting season, Włocławek Reservoir, Poland. Pectoral muscle, liver, and kidney sampled per bird. All concentrations are total mercury in mg/kg wet weight.
• Table 1, all birds (n = 30): liver mean 0.154 (SD 0.145, median 0.105, Q25-Q75 0.064-0.170, min-max 0.010-0.689); kidneys mean 0.122 (SD 0.092, median 0.101, Q25-Q75 0.052-0.145, min-max 0.013-0.423); muscles mean 0.110 (SD 0.196, median 0.055, Q25-Q75 0.027-0.091, min-max 0.009-0.925).
• Tissue ranking by mean: liver > kidneys > muscles. The Mann-Whitney U test found that tissue mean differences across the full cohort were not statistically significant; Spearman correlations between every tissue pair were significant at p ≤ 0.01.
• Cohort splits into two subpopulations by Σ-tissue Hg threshold 0.600 mg/kg wet weight. Subpopulation I (n = 23, Σ < 0.600): liver mean 0.100, kidneys 0.088, muscles 0.049. Subpopulation II (n = 7, Σ > 0.600): liver mean 0.330, kidneys 0.233, muscles 0.309. Subpopulation II contains individual birds with muscle Hg up to 0.925 mg/kg wet weight (Table 4, bird 15).
• Each per-sample reported value is the arithmetic mean of three analytical replicates on that sample.
• The authors conclude that mercury levels were “relatively high” but that, given the share of wild-duck meat in the Polish diet, consumption of a 100 g portion from the high-Σ subpopulation covers approximately 9% of the WHO PTWI (5 µg/kg body weight, of which methylmercury should not exceed 1.6 µg/kg body weight) for a 70 kg adult.

Methods (brief)

Mercury was measured by cold-vapor atomic absorption spectrometry (CV-AAS) on an Altec AMA-254 automatic mercury analyzer (Prague, Czech Republic). The analyzer was calibrated with a polarographically pure mercury standard in 2% HNO3. Detection limit was 0.001 mg Hg/kg. Method validation used BCR CRM 463 (tuna fish) reference material with certified Hg concentration 2.85 mg/kg; the recovered value was 2.49 mg/kg (87.36% recovery). Samples (≤ 300 mg per aliquot) of pectoral muscle, liver, and whole kidney (cranial, medial, and caudal divisions combined) were analyzed; each sample was measured in triplicate and reported as the arithmetic mean of the three replicates. Concentrations are reported per kilogram of wet tissue. The paper reports total mercury only; no inorganic/methylmercury speciation was performed. Statistical analyses were run in Statistica 12; normality was tested with the Shapiro-Wilk W test and rejected, so tissue-pair differences were tested with the non-parametric Mann-Whitney U test and tissue-pair associations with Spearman rank correlation at p ≤ 0.05 and p ≤ 0.01 thresholds.

Implications

Certification: This source supports game-meat mercury context for wild birds but does not support methylmercury-specific certification rows.

Courses: It helps explain why organ tissue and muscle tissue should not be pooled without a basis label.

App: It can provide context for wild duck or game-bird entries where relevant.

Wiki pages this source may touch

• Game meats (venison, bison, rabbit)
• Meat and poultry
• Organ Meats (Kidney and Liver)
• Mercury, Total

Verification notes

The source reports total Hg by tissue. Do not route it to methylmercury without a separate speciation source.

Page history

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