Pankiewicz 2012 — Total mercury in dairy products from south-east Poland
This study measured total mercury in 48 dairy products from six regional milk cooperatives across south and south-east Poland (Lublin, Podkarpackie, Silesia, and adjacent regions) using non-flame atomic absorption (AMA-254 direct mercury analyzer). Mercury levels ranged from 0.01 µg/kg on a wet-product basis (reached by natural kefir from two cooperatives, cream, buttermilk, and strawberry flavoured yogurt) up to 0.79 µg/kg (butter extra), all well below the Polish national maximum permissible level of 10 µg/kg for milk. Butter and whole milk powder consistently showed the highest concentrations across producers; kefir consistently showed the lowest. Speciation was not measured (total Hg only).
Key numbers
Mercury content in product (mean ± SD, µg/kg wet product basis, Table 1). Producer letter codes A–F as in the paper, in lieu of producer identification.
Producer A (n=10): Milk 0.06 ± 0.01; Kefir 0.02 ± 0.01; Natural yogurt 0.03 ± 0.00; Natural yogurt (second product line) 0.05 ± 0.01; Cream 0.06 ± 0.02; Cream cheese (vanilla) 0.12 ± 0.00; Half-fat cottage cheese 0.23 ± 0.01; Whole milk powder 0.30 ± 0.01; Buttermilk 0.09 ± 0.03; Butter extra 0.79 ± 0.79.
Producer B (n=8): Milk 0.03 ± 0.01; Cream cheese (vanilla) 0.05 ± 0.02; Cream cheese (natural) 0.05 ± 0.01; Cream 0.04 ± 0.01; Cream cheese with horseradish 0.09 ± 0.04; Cream cheese with caraway 0.06 ± 0.02; Natural buttermilk 0.06 ± 0.01; Half-fat cottage cheese 0.10 ± 0.01.
Producer C (n=10): Natural yogurt 0.07 ± 0.02; Cream cheese (vanilla) 0.14 ± 0.01; Cream cheese (natural) 0.05 ± 0.01; Natural yogurt (second product line) 0.03 ± 0.00; Buttermilk 0.01 ± 0.01; Kefir 0.01 ± 0.01; Cream 0.03 ± 0.02; Milk 0.03 ± 0.02; Half-fat cottage cheese 0.04 ± 0.01; Butter extra 0.58 ± 0.26.
Producer D (n=8): Cream cheese (vanilla) 0.04 ± 0.02; Yogurt (probiotic-marketed) 0.06 ± 0.04; Strawberry flavoured yogurt 0.01 ± 0.01; Tzatziki (cucumber and garlic) 0.02 ± 0.01; Cream 0.01 ± 0.01; Natural yogurt 0.04 ± 0.02; Natural kefir 0.01 ± 0.00; Cream cheese (vanilla, second product line) 0.11 ± 0.05.
Producer E (n=6): Cream 0.05 ± 0.04; Natural cottage cheese 0.12 ± 0.02; Natural cottage cheese (second product line) 0.08 ± 0.02; Cream cheese with spring onion 0.16 ± 0.04; Kefir 0.04 ± 0.02; Half-fat cottage cheese 0.13 ± 0.07.
Producer F (n=6): Cream 0.03 ± 0.01; Kefir 0.02 ± 0.01; Granular cottage cheese 0.08 ± 0.03; Half-fat cottage cheese 0.05 ± 0.03; Butter extra 0.47 ± 0.16; Milk 0.06 ± 0.02.
Range minima and maxima by category (µg/kg product, wet basis): kefir 0.01–0.04; milk 0.03–0.06; natural yogurt 0.01–0.07; buttermilk 0.01–0.09; cream 0.01–0.06; cream cheese 0.04–0.16; cottage cheese 0.04–0.23; butter extra 0.47–0.79; whole milk powder 0.30 (single sample). Across all 48 samples mercury concentration in product ranged 0.01–0.79 µg/kg. Detection limit of the AMA-254 instrument was 10⁻⁵ µg/g (0.01 ng/g, equivalent to 0.01 µg/kg on a mass basis).
Comparative cited values for milk and dairy mercury from the literature (Pankiewicz Discussion, with cite-key references retained from the paper): Korea (Roh 1975) 3–10 ppb; North Dakota (Sell 1975, Sell and Davison 1975) <1–2 ppb; Poland Wrocław (Dobrzański 2009) 0.24 and 0.27 ppb; Silesia late 1980s 0.3–6.7 ppb; Zgorzelec/Bogatynia region ~2 ppb; Spain Canary Islands 0.09–0.61 ppb; China 1.0–3.9 ppb; Italy Rome surroundings 0.9–38 ppb; Egypt 86–556 ppb. National maximum mercury content for foodstuffs cited as 1 mg/kg in Sweden and Japan, 1.5 mg/kg in Norway, 0.5 mg/kg in Poland (general foodstuffs); Polish maximum for mercury in milk specifically established at 10 µg/kg (10 ppb).
Regulatory limits cited by the paper: EU Commission Regulation (EC) No. 1881/2006 of 19 December 2006 sets maximum mercury concentration explicitly only for fish and seafood (0.5 mg/kg wet weight, or 1.0 mg/kg for selected species) and not for dairy. Polish national permissible Hg in milk = 10 µg/kg (10 ppb). JECFA provisional tolerable weekly intake (PTWI) for mercury from all sources = 5 µg/kg body weight/week, including 1.6 µg/kg body weight/week for organic mercury compounds (the JECFA PTWI for methylmercury has since been revised downward; this paper cites the 2009-era values).
Methods (brief)
Forty-eight dairy products purchased from local markets in regions of varying industrialization across south and south-east Poland. Water content of products determined separately on a Radwag WPS50SW moisture analyzer by drying at 100 °C in triplicate. Samples lyophilized in a Labconco Model 64132 freeze dryer (Kansas City, MO, USA) and lyophilizates stored in an exsiccator. Total mercury determined on lyophilized samples by non-flame atomic absorption spectrometry with thermal decomposition and gold-amalgam trapping (AMA-254 mercury analyzer, Altec, Czech Republic): samples pre-dried in the internal oven, burned in oxygen (99.999% purity), decomposition products carried to amalgamator for selective Hg trap, amalgamator stabilised at 120 °C, mercury released by short heat-up and quantified in a double measuring cuvette at two sensitivities. Dynamic range 0.05–600 ng Hg per measurement; instrumental detection limit 10⁻⁵ µg/g. Calibration controlled with NIST-traceable Hg standard solutions (AccuStandard, New Haven, CT, USA). Each sample analyzed in triplicate; reported values are mean ± SD. Hg in lyophilizate converted to Hg in base product using the measured water content of each product. Speciation not measured — total Hg only; no MeHg or inorganic-Hg fractionation.
Implications
- Certification (HMTc): Polish regional cooperative dairy products contribute to the dairy total-Hg occurrence baseline. All 48 samples fall well below the 10 µg/kg Polish national permissible limit for milk and orders of magnitude below the EU 0.5 mg/kg limit for fish. Within-category gradient is consistent across producers: butter (0.47–0.79 µg/kg) > whole milk powder (0.30 µg/kg) > cottage and cream cheese (0.04–0.23 µg/kg) > fluid milk (0.03–0.06 µg/kg) ≈ cream and buttermilk ≈ yogurt > kefir (0.01–0.04 µg/kg). The gradient is consistent with concentration of Hg into the lipid and lyophilised fractions during processing rather than with fermentation reducing Hg load. Useful sub-format granularity for the dairy occurrence baseline.
- Courses: Demonstrates the value of AMA-254 direct-mercury analysis at sub-ppb detection limits for dairy QC and illustrates how product moisture content drives apparent concentration differences across dairy formats (butter > milk powder > cheese > fluid milk > fermented). Also serves as a regional reference for Polish dairy supply chains drawing from south-east Poland (Lublin, Podkarpackie).
- App: Contributes Hg occurrence data to the milk-and-dairy ingredient page and the butter-and-ghee product page in a European context, with sub-category structure for butter, milk powder, cottage cheese, cream cheese, yogurt, kefir, and buttermilk. Values sit in the lower tail of the dairy total-Hg distribution and contribute occurrence weight rather than threshold-setting weight.
Wiki pages this source may touch
Verification notes
2026-05-19 (Claude Code, merge-enhance and duplicate consolidation). Two source pages existed for this paper: this page (pankiewicz2012-thg-dairy-products-poland.md, last updated 2026-05-17) and a legacy duplicate (pankiewicz2012-mercury-dairy-products-poland.md, last updated 2026-05-14). Both shared the same DOI (10.2428/ecea.2012.19(01)014). The legacy duplicate had three defects that the routing audit and downstream synthesis would have propagated: (a) units reported as mg/kg throughout the body, when Table 1 of the source uses µg/kg (the source page-1 abstract has a “10 mg/kg” typo for what the source itself elsewhere clarifies as 10 µg/kg / 10 ppb — the Polish national limit); (b) frontmatter slugs ingredients/milk and ingredients/cheese that do not exist in the current taxonomy; and (c) evidence_tier: A instead of B (single-author regional survey without speciation does not meet the A-tier bar). The legacy duplicate has been removed; this page is the canonical source-page for the paper.
Frontmatter defects corrected in this revision. Previous frontmatter listed [[ingredients/cheddar-cheese]] and [[ingredients/half-and-half]]. The source paper measures cottage cheese, cream cheese, and cream — not cheddar cheese and not half-and-half. Both invented slugs were removed; [[ingredients/whole-milk]], [[ingredients/yogurt]], [[ingredients/butter]], and [[ingredients/milk-and-dairy]] are retained because they match real wiki ingredient pages and the source measures all four. Kefir, cottage cheese, cream cheese, buttermilk, and milk powder are carried in the matrices: field instead because no individual wiki ingredient pages exist for those sub-forms (they would fall under the milk-and-dairy umbrella per Part 10 unless and until promoted by the 5-paper rule).
Brand firewall (Part 12, strict 2026-05-17 reading). The source paper uses anonymised producer codes (OSM A–F) for the six regional milk cooperatives; those letter codes are scientific anonymisation and are retained in the per-OSM table to preserve the within-producer / across-producer gradient that is one of the paper’s findings. However, the paper also includes proper-noun product-line identifiers in Table 1 (six distinct trade-marked product-line names) and the Polish-language abstract names two specific producer locations and a specific kefir brand. All of those proper-noun brand identifiers have been scrubbed from this wiki page. Descriptive product attributes that are not proper nouns (e.g., “vanilla flavoured cream cheese”, “cream cheese with horseradish”, “tzatziki with cucumber and garlic”, “strawberry flavoured yogurt”) are retained because they describe the product format rather than identify a brand. Where Producer A or D produced two distinct natural-yogurt or vanilla-cream-cheese product lines that the paper reports separately, the two are distinguished here as “(second product line)” rather than by trade name.
Wiki/HMTc firewall (Part 2). No HMTc threshold proposals or certification-aligned framing in ## Implications; the section limits itself to what this single occurrence study contributes to the dairy total-Hg baseline. Direction of edit: toward the literature (correcting unit error and invented slugs makes the wiki more accurately reflect the source); no movement toward HMTc convenience.
Speciation. Total mercury only (AMA-254 with thermal decomposition). Paper does not report MeHg, iHg, or any speciation fractionation. metals: therefore lists tHg only and not MeHg or iHg.
Source unit inconsistency preserved as a caveat. The English-language abstract on page 1 of the source contains the line “the mercury content was lower than the permissible level of 10 mg/kg” with a unit typo: the rest of the paper (Table 1 column header, Results and Discussion, the Polish-language abstract, and the explicit “10 µg/kg (10 ppb)” statement on page 7) makes clear that the permissible level is 10 µg/kg and the data are in µg/kg. The wiki page uses µg/kg consistently because that is the unit the source’s own data table and discussion are reported in.
Detection-limit reinterpretation flagged (audit subagent 2026-05-19). Source page 2 states the AMA-254 instrumental detection limit as “10⁻⁵ mg/g”. Taken literally, 10⁻⁵ mg/g equals 10 µg/kg, which is inconsistent with the minimum reported product-basis values of 0.01 µg/kg in Table 1 (the reported floor is three orders of magnitude below the stated DL). The source’s units are internally inconsistent (the same paper has the page-1 abstract “10 mg/kg” typo for what is elsewhere clarified as 10 µg/kg). This wiki page reinterprets the stated “10⁻⁵ mg/g” as “10⁻⁵ µg/g” (= 0.01 ng/g = 0.01 µg/kg), which is the only DL value consistent with both (a) the AMA-254 specification and (b) the lowest reported Table 1 value. The reinterpretation is documented here rather than silently presented as the source’s literal text. Audit subagent (2026-05-19) flagged this as a ⚠️ documentation issue; verified against source page 2 — finding correct, applied as a verification-notes flag rather than as a re-quoted value.
Audit subagent (2026-05-19) ⚠️ on floor-value attribution. Original opening paragraph attributed the 0.01 µg/kg floor to kefir only. Source page 3 explicitly names the floor as reached by “natural kefir (7D, 6C), cream (5D), buttermilk (5C) and strawberry flavoured yogurt (3D)” — four product formats from four cooperatives. Opening paragraph revised to enumerate all four; finding verified correct and applied.
Products field. [[products/butter-and-ghee]] retained because the source measures butter extra (n=3 across OSMs A, C, F at 0.47–0.79 µg/kg) and wiki/products/butter-and-ghee.md is an HMTc-locked product page (Category 7, Row 3). No locked HMTc row exists yet for fluid milk, yogurt, kefir, cottage cheese, cream cheese, buttermilk, or milk powder; those formats route via the matrices: field rather than via products:.
Page history
The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.