Slepecka et al. 2017 - Cadmium, lead, zinc, and copper in ecological vs. non-ecological cereal products, Poland
This study compared cadmium, lead, zinc, and copper concentrations in 10 ecological and 10 non-ecological cereal products from Poland. The source uses “ecological” for products from ecological/organic production systems. The sampled foods included flours, brans, flakes, and oatmeal made from wheat, spelt, rye, buckwheat, oat, and barley. The main finding is that ecological products were not distinguished by lower heavy-metal concentrations; in several product categories, ecological samples had higher Cd, Pb, Cu, or Zn than their non-ecological counterparts.
Key numbers
All concentrations are mg/kg. The authors cite PN-EN 14084:2004P reference levels as Cd 0.20 mg/kg, Pb 0.20 mg/kg, Zn 73.5 mg/kg, and Cu 10.3 mg/kg; this page treats those values as the paper’s cited comparator rather than independently re-validating the standard.
Flour findings:
| Analyte | Ecological flour | Non-ecological flour |
|---|---|---|
| Cd | Mean 12.28 mg/kg | Mean 0.12 mg/kg; detected in wheat type 2000 and rye type 2000; spelt and buckwheat reported as without Cd contamination |
| Pb | Mean 2.07 mg/kg; range 1.28 mg/kg in spelt flour to 2.88 mg/kg in rye flour | Mean 8.73 mg/kg; range 0.26 mg/kg in buckwheat flour to 30.10 mg/kg in spelt flour |
| Cu | Mean 23.98 mg/kg | Mean 14.55 mg/kg; wheat-flour Cu could not be determined because it exceeded the measuring-device detection limit |
| Zn | Mean 48.2 mg/kg; highest ecological wheat flour 55.69 mg/kg | Mean 38.46 mg/kg; highest non-ecological spelt flour 73.3 mg/kg; wheat-flour Zn could not be determined because it exceeded the measuring-device detection limit |
Bran findings:
| Analyte | Ecological bran | Non-ecological bran |
|---|---|---|
| Cd | Mean 26.3 mg/kg | Not detected |
| Pb | Mean 6.07 mg/kg; range 0.28 mg/kg in rye bran to 16.25 mg/kg in oat bran | Mean 2.24 mg/kg; range 2.07 mg/kg in oat bran to 2.44 mg/kg in rye bran |
| Cu | Mean 28.93 mg/kg; range 23.56 mg/kg in wheat bran to 38.39 mg/kg in oat bran | Mean 27.40 mg/kg; range 26.93 mg/kg in wheat bran to 27.93 mg/kg in rye bran |
| Zn | Mean 110.10 mg/kg; range 68.91 mg/kg in wheat bran to 131.42 mg/kg in rye bran | Mean 98.79 mg/kg; range 81.70 mg/kg in rye bran to 123 mg/kg in oat bran |
Flake findings:
| Analyte | Ecological flakes | Non-ecological flakes |
|---|---|---|
| Cd | Mean 20.70 mg/kg; range 16.90 mg/kg in barley flakes to 23.75 mg/kg in oatmeal/oat flakes | Below the determination limit |
| Pb | Mean 1.58 mg/kg; range 0.39 mg/kg in oatmeal/oat flakes to 2.44 mg/kg in rye flakes | Mean 2.43 mg/kg; range 2.12 mg/kg in oatmeal/oat flakes to 2.61 mg/kg in rye flakes |
| Cu | Mean 19.98 mg/kg; range 18.91 mg/kg in barley flakes to 20.77 mg/kg in oatmeal/oat flakes | Mean 26.26 mg/kg; range 25.22 mg/kg in oatmeal/oat flakes to 27.16 mg/kg in rye flakes |
| Zn | Mean 48.95 mg/kg; range 37.55 mg/kg in barley flakes to 48.81 mg/kg in oatmeal/oat flakes | Mean 77.88 mg/kg; range 34.30 mg/kg in barley flakes to 132.00 mg/kg in rye flakes |
Source conclusion against the authors’ cited PN-EN 14084:2004P comparator:
- Ecological products were not distinguished by lower heavy-metal content than non-ecological products.
- All tested cereal products except conventional flours and ecological buckwheat flour exceeded the Cd level permitted by the cited standard.
- All products contained Pb above the cited standard.
- Ecological products had higher Cu content than conventional products overall, and all ecological products exceeded the cited Cu level; conventional rye flour and wheat flour met the cited Cu standard.
- Zn levels were similar across ecological and non-ecological products overall; ecological rye and oat bran and non-ecological rye flakes, wheat bran, rye bran, and oat bran exceeded the cited Zn level.
Methods (brief)
The authors selected 10 ecological and 10 non-ecological cereal products from different producers and regions of Poland. Product types were oatmeal, barley flakes, rye flakes, wheat bran, rye bran, oat bran, wheat flour type 2000, spelt flour type 2000, rye flour type 2000, and buckwheat flour.
Sample preparation used 0.5 g product weighed to 0.001 g, 3 mL 65% nitric acid (Merck, Germany), microwave mineralization in a MARS 5 oven at 200 deg C for 20 minutes, transfer to a 50 mL volumetric flask, and dilution with deionized water. Pb, Cd, Zn, and Cu were measured by flame atomic absorption spectrometry (FAAS) using a Varian AA-280 FS instrument. The authors calculated averages and standard deviations and used a Student t-test with p=0.05 in Statistica 13.1.
Speciation and methods caveats
- Pb, Cd, Zn, and Cu are reported as total element concentrations; no chemical species are distinguished.
- The paper is a small occurrence survey (20 products total), and the group means are mostly reported in narrative text and figures rather than sample-level tables.
- The paper does not report LODs, LOQs, certified-reference-material recoveries, or blank values.
- The Cd values reported for ecological flours, bran, and flakes are far above the authors’ cited 0.20 mg/kg comparator. The source does not flag a unit anomaly, so this page preserves the source’s mg/kg values but treats the source as B-tier and flags the values for cautious use.
Implications
Standards work: This source contributes Polish occurrence context for Cd, Pb, Zn, and Cu in cereal flours, bran, and flakes. It is most useful as a cautionary small-study datapoint: the reported Cd values are far above the authors’ cited 0.20 mg/kg comparator, and the paper lacks enough QA/QC detail to use the values as a primary threshold anchor without corroboration.
Courses: The paper is useful for teaching that ecological/organic production status does not by itself demonstrate lower metal concentrations. It also illustrates why bran and whole-grain fractions need separate attention from refined flours when source data are available.
App: The source can support ingredient-derivative context for bran-containing cereal products, but any display should label the dataset as a small Polish survey and preserve the B-tier caution on very high Cd values.
Wiki pages this source may touch
Verification notes
- Merge-enhanced 2026-05-18 from the full manual-fetch PDF path and SHA-256 recorded in frontmatter.
- Kept evidence_tier B because the source is a small 20-product survey with values reported mainly from figures/narrative text and limited analytical QA/QC reporting.
- Replaced older HMTc-threshold and cross-source-consensus phrasing with source-only implications.
- Replaced invalid ingredient links to non-existent
oats,rye, andbarleypages with existing vocabulary routes. - Strict brand-firewall check: no consumer brands are named; instrument, reagent, and software vendor names are retained only as Methods details under the Part 12 scientific-method exception.
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.
| Commit | Date | Description |
|---|---|---|
| b0f3d38 | 2026-06-12 | batch | corpus rescreen b04 old terminal skips |