Bielecka 2021 - Toxic elements in nuts

Bielecka and colleagues measured arsenic, cadmium, lead, and mercury in 120 edible nut samples available on the Polish market. The paper reports values by nut subgroup and evaluates dietary risk indicators. Arsenic and mercury are total-element measurements; the paper does not report inorganic arsenic or methylmercury speciation.

Key numbers

Table 1 reports concentrations in ug/kg. The abstract highlights the highest median values: As in pistachios 192.42 ug/kg, Cd in pine nuts 238.40 ug/kg, Pb in peanuts 82.06 ug/kg, and Hg in pecans 82.06 ug/kg in the extracted abstract text. In the Table 1 body, the pecan Hg median is 5.77 ug/kg; this discrepancy is preserved here rather than reconciled.

Selected Table 1 rows:

The abstract reports that Pb exceedances of an established limit were found in nine samples: macadamia nuts 221.49 ug/kg, 2350.94 ug/kg, and 2581.43 ug/kg; pine nuts 266.33 ug/kg; peanuts 1353.80 ug/kg; and pecans 2689.13 ug/kg, 2758.26 ug/kg, 2992.29 ug/kg, and 3169.41 ug/kg. The authors state that extremely high Pb content, above 2500 ug/kg, occurred in 33% of studied pecans imported from the USA.

The Results text states that the highest individual As value was 314.52 ug/kg in a pecan sample imported from the USA; the highest individual Cd value was 458.22 ug/kg in a pine-nut sample imported from China; the highest individual Pb value was 3169.41 ug/kg in pecans imported from the USA; and the highest individual Hg value was 44.74 ug/kg in walnuts grown in Poland.

Methods (brief)

Samples were purchased from markets in standard packages and by weight. The authors homogenized nuts with an Ultra-Turrax. For As, Cd, and Pb, 200-300 mg samples were digested with concentrated nitric acid using closed-vessel microwave mineralization and analyzed after dilution. Arsenic was measured by ICP-MS; cadmium and lead were measured by ETAAS with Zeeman background correction; mercury was measured directly without digestion using AAS with amalgamation.

Implications

This source provides direct market occurrence evidence for nuts and peanuts across Pb, Cd, total As, and total Hg. The clearest row-specific contamination signal is lead in pecans, macadamia nuts, pine nuts, and peanuts, with several single-sample values far above the table medians. Because the taxonomy does not yet include dedicated pecan, pine-nut, pistachio, Brazil-nut, or macadamia product rows, those findings should remain visible through the broad nuts/seeds route until narrower rows are available.

Verification notes

• PDF text was extracted with pdftotext -layout; title/byline, abstract, sample collection, methods, Table 1, Results, and Conclusions were checked in /tmp/f3_unrepresented_texts/nutrients-13-03606-v2.txt.
• DOI 10.3390/nu13103606, raw handle MFK_nutrients-13-03606-v2, and cite-key checks found no existing source page before creation.
• Units are preserved as ug/kg; no conversion to mg/kg or serving basis was performed.
• Speciation: arsenic and mercury are total-element measurements. The source does not report inorganic arsenic or methylmercury.
• Frontmatter slugs were checked against docs/gpt-collaboration/taxonomy-snapshot.md; missing narrow ingredient/product slugs include Brazil nuts, macadamia nuts, pecans, pine nuts, and pistachios.

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.