Reczajska et al. 2005 — Chromium content of plant-origin foods and beverages in Poland
A total of 272 samples of fresh edible plants and beverages were analyzed for total chromium using ZETAAS (electrothermal AAS with Zeeman background correction) to assess dietary chromium from plant sources in Poland. Chromium ranged from below 1 to 183 µg/kg fresh weight across all sample types, with the highest concentrations in wheat grains and strawberries and the lowest in juices. Regional differences across three Polish provinces were observed, and results were generally lower than older Polish reference values, consistent with updated analytical methods that reduce contamination artifacts from prior techniques.
Key numbers
| Commodity | n | Range (µg/kg f.w.) | Mean (µg/kg f.w.) | Median | 90th percentile |
|---|---|---|---|---|---|
| Strawberries | 42 | 6–134 | 32 | 28 | 56 |
| Apples | 23 | 2–63 | 11 | 9 | 16 |
| Cucumbers | 23 | 1–74 | 19 | 10 | 40 |
| Cabbages | 23 | <1–15 | 6 | 5 | 10 |
| Carrots | 43 | <1–18 | 6 | 4 | 12 |
| Potatoes | 24 | <1–11 | 3 | 4 | 9 |
| Wheat grains | 45 | <2–183 | 39 | 27 | 79 |
| Wines | 10 | 10–16 µg/L | 12 µg/L | 12 µg/L | 17 µg/L |
| Beers | 10 | 6–8 µg/L | 7 µg/L | 8 µg/L | 13 µg/L |
| Juices/beverages | 10 | <1 µg/L | <1 µg/L | — | <1 µg/L |
Regional breakdown for strawberries (µg/kg): Mazowieckie mean 36, Lubelskie mean 21, Kujawsko-Pomorskie mean 47.
Methods (brief)
Electrothermal AAS with Zeeman background correction (ZETAAS) at 357.9 nm. Solid samples digested by closed-vessel microwave with concentrated HNO3. Liquid samples diluted with HNO3 without digestion. LOD approximately 1 µg/kg (or µg/L) for 1-g samples; approximately 2 µg/kg for 0.3-g samples. Method validated against certified reference material CTA-VTL-2 (Virginia Tobacco Leaves); recoveries 94–104%. Note: this paper measures total chromium only; Cr-VI speciation was not performed.
Implications
Certification: Total Cr values in Polish fruits and vegetables are generally low (mean <40 µg/kg). However, this is total Cr, not Cr-VI. Per CLAUDE.md Part 14, total Cr must never be treated as Cr-VI unless the source speciates hexavalent chromium; this source does not.
Courses: Useful for illustrating geographic variation in Cr content within a single country and the importance of analytical method quality (older contamination-prone AAS methods produced spuriously high values).
App: Provides total Cr concentration ranges for strawberries, apples, cucumbers, cabbages, carrots, potatoes, and wheat grain from a Polish 2001 survey. Confidence: low (single study, older data, total Cr only).