Sembratowicz et al. 2010 — Lead and cadmium in domestic fruits from Lublin allotments, Poland

Sembratowicz and colleagues measured lead, cadmium, and nitrates (III)/(V) in five domestic fruit species (apple, plum, strawberry, raspberry, white grape) drawn from allotment gardens in central Lublin and from rural allotments 15–20 km outside the city. Lead was determined by non-flame AAS on a Varian Spectra AA 880Z with deuterium background correction following dry mineralisation at 450 °C per PN-EN 14082; cadmium by the same method on the same digests. The mean lead concentration exceeded the EU 1881/2006 maximum permissible level (0.10 mg/kg f.m. for non-berry fruits; 0.20 mg/kg f.m. for berries and small fruits) in the majority of analysed lots, while cadmium exceeded its limit (0.050 mg/kg f.m.) only in white grape, where every grape lot was above the limit regardless of harvest site. A significant site effect (p ≤ 0.05) was found for raspberry lead (higher in city-centre gardens) and strawberry cadmium (higher in city-centre gardens); no consistent site effect was observed for the other species.

Key numbers

Sample structure (Materials and Methods, p. 161–162). Two harvest sites × five fruit species. Sample counts per site: apple 10, plum 10, strawberry 12, raspberry 12, white grape 10 (54 lots per site, 108 lots total). Each determination performed in duplicate. Fruits were washed with deionised water, inedible parts removed, dried at 60 °C and then 103 °C, ground in a WŻ-1 mill, and stored in glass containers before analysis.

Lead in fruits — fresh-mass basis (Table 2, p. 163). Values in mg/kg fresh weight. “<NDZ %” gives the share of samples below the EU maximum permissible level (column header NDZ = Polish najwyższe dopuszczalne zanieczyszczenia, “highest permissible content”); a dash means no samples in that row were below the MPL. Letters a/b denote site means differing significantly at p ≤ 0.05.

Cadmium in fruits — fresh-mass basis (Table 2, p. 163). Same units and conventions.

Lead and cadmium on a dry-mass basis (Table 3, p. 164). Means in mg/kg dry weight. Letters a/b denote site differences significant at p ≤ 0.05.

Regulatory comparison (Discussion, p. 164). Per EU Commission Regulation (EC) 1881/2006 as in force at the time, the lead MPL for berries and small fruits is 0.20 mg/kg f.m. and for other fruits is 0.10 mg/kg f.m.; the cadmium MPL is 0.050 mg/kg f.m. The “exceeding permissible content was recorded” verdict applies to: apple (both sites mean Pb < 0.10 by a thin margin, but 30–50% of individual lots were above), plum (both sites mean Pb = 0.13, above 0.10), strawberry (both sites mean Pb above 0.20), and raspberry from the city centre (mean Pb 0.27, above 0.20). Raspberry from the surroundings and white grape from both sites did not exceed the Pb MPL. For cadmium, the MPL was exceeded only by white grape (means 0.19 and 0.22, both well above 0.050), with 100% of lots above the limit at each site.

Nitrates (III) and nitrates (V) — fresh-mass basis (Table 1, p. 162). Reported as mg NaNO₂/kg f.m. and mg KNO₃/kg f.m. respectively. * indicates below detection. The text notes that the nitrate sum in fruits is “negligible as compared to the values found in vegetables, namely leafy ones” and that EU 1881/2006 does not set a fruit nitrate MPL.

Methods (brief)

Fruit lots were washed in deionised water (Direct Q 5 deioniser; Millipore, France), inedible parts removed, air-dried, then dried at 60 °C and re-dried at 103 °C in an electric drier; the dried material was ground in a WŻ-1 mill and stored in glass containers. Dry-mass content per lot was determined by drier-weight method (PN-A-79011-3:1998). For trace-metal analysis, 5 g aliquots were dry-mineralised at 450 °C in quartz crucibles in a muffle furnace; ash was dissolved in 5 cm³ of 6 N spectra-pure HCl (Merck) and brought to 100 cm³ in volumetric flasks with deionised water. Lead and cadmium were quantified per PN-EN 14082 by non-flame AAS on a Varian Spectra AA 880Z spectrometer with deuterium background correction at the Central Apparatus Laboratory, University of Life Sciences in Lublin (the PDF specifies “non-flame AAS”; PN-EN 14082’s non-flame pathway is graphite furnace). Detection wavelengths were 217.0 nm (Pb) and 228.8 nm (Cd) with detection limits of 50 µg/L and 5 µg/L respectively; calibration used dilutions of Merck 50 µg/L (Pb) and 2.5 µg/L (Cd) standards, and the analytical procedure was validated against the oriental tobacco CRM CTTA-OTL-1 (Poland). Nitrates (III) and (V) were determined per PN-92/A-75112 by colorimetric measurement of the Griess-reagent reaction. All determinations were duplicate. Differences between site means were tested by one-way ANOVA at α = 0.05 in Statistica 6. No analyte speciation was performed; reported Pb and Cd are total elemental concentrations.

Implications

Certification: Polish allotment fruits show lead concentrations that routinely sit above EU 1881/2006 limits for both berries (0.20 mg/kg f.m.) and tree fruits (0.10 mg/kg f.m.), with the strawberry, raspberry (city centre), and plum group means all above their applicable MPL. Cadmium exceedance is concentrated entirely in white grape, where 100% of lots from both sites were above the 0.050 mg/kg f.m. limit and means were roughly 4× the MPL. The values are from allotment-garden plots (not retail) and reflect site-specific soil and proximity-to-road conditions, so they bound upper-tail exposure for self-harvested rather than commercial fruit. Contributes occurrence data to the lead and cadmium contamination profiles for apple, plum, strawberry, raspberry, and grape ingredient pages.

Courses: Useful for two teaching points — (i) site effects can be species-specific (raspberry Pb and strawberry Cd both differ significantly by site, but apple, plum, and white grape do not), and (ii) the dry-weight versus fresh-weight basis swing (Table 2 vs Table 3) is roughly an order of magnitude and demonstrates why basis conversion is mandatory before any threshold comparison. Also illustrates that nitrate(V) loading in strawberries can reach the hundreds of mg/kg even though fruit-category nitrates are not regulated under EU 1881/2006.

App: Occurrence data for self-harvested Polish allotment fruits, distinct from retail-market data; Pb tends higher in urban/roadside lots, Cd is the dominant exceedance signal for white grape regardless of site. Useful as an upper-bound prior for allotment- or garden-sourced fruit consumption scenarios but should not be used in place of retail-market data for general commodity profiling.

Verification notes

Page rewritten 2026-05-19 from a 2026-05-14 revision against the source PDF. Corrections applied:

• Key numbers — Pb table site labels swapped. The prior revision had every row’s “Lublin centre” and “Lublin surroundings” labels transposed against the PDF Table 2 (p. 163). Verified row-by-row from the PDF and against the Discussion text on p. 164 (“0.06 mg kg⁻¹ FW in white grapes from the gardens in the city center to 0.31 mg kg⁻¹ FW in strawberries harvested from the city’s suburbia”) and the Conclusions on p. 165 (“Far higher levels of these metals were recorded in the fruits harvested in the city gardens” — raspberry Pb 0.27 a is city-centre, 0.09 b is surroundings). All ten Pb rows re-labelled to match the source.
• Cd table expanded from one fruit to all five. The prior revision listed cadmium values only for white grape and described the other species in prose; the source Table 2 reports the full five-fruit × two-site cadmium matrix, including the significant strawberry city-centre-versus-surroundings difference (0.04 a vs 0.01 b). All ten Cd rows added from the source.
• Dry-mass table (Table 3) added. The prior revision only mentioned that dry-weight values existed; the full ten-row dry-mass table is now reproduced.
• Nitrate (III) and (V) table added. The prior revision did not report the nitrate data even though nitrates are half of what the paper measures. The paper’s framing is that nitrates in these fruits are well below the levels seen in leafy vegetables and below the EU ADI; reproducing the table preserves that result without crossing the wiki/HMTc boundary (nitrates are not in the HMTc analyte list).
• raw_handle: corrected from manual-fetch-kimi (parent-folder placeholder, not a per-paper handle) to MFK_contents-of-nitrates-iii-and-v-lead-and-cadmium per the v2 manual-fetch handle convention.
• raw_path: corrected from the truncated …Cadmium in the Selec.pdf to the actual PDF filename …Cadmium in the Selected Domestic Fruits from Lublin Region.pdf.
• raw_sha256: added (b7a71ffc9da2312225e0845723f8c7a74fc0001af85741c6238aa923b2443b65).
• ingredients: corrected [[ingredients/apples]] (no such slug; wiki/ingredients/apples.md does not exist) to [[ingredients/apple]] (the actual slug, singular). All four other ingredient slugs (plums, strawberries, raspberries, grapes) were valid and were retained as-is.
• sample_n: corrected from 108 to 54 per-site (with the 108 figure relocated into sample_population as the total across both sites × five species). The prior figure conflated per-site lot count with total determinations.
• sample_population: rewritten to include the rural-allotment village names from the source (Niedrzwica Duża, Niedrzwica Kościelna, Krężnica Jara, Łuszczów, Biskupice), the harvest window (July–September 2007), and the duplicate-determination structure.
• Implications section rewritten to reflect what the paper actually reports, with the corrected Pb-table site labels driving the species-specific conclusions about city versus surroundings effects.
• Legacy ## Wiki pages updated on ingest section replaced with ## Wiki pages this source may touch per the current Part 6 source-page template.
• Audit subagent (2026-05-19, fresh-context QA) flagged the wording “non-flame (graphite-furnace) AAS” in the summary and Methods as an inference (the PDF says only “non-flame AAS technique” without naming graphite-furnace, though PN-EN 14082’s non-flame pathway is graphite-furnace and the LODs are consistent). Softened both occurrences to make the inference explicit rather than implicit: the lead paragraph now says “non-flame AAS … per PN-EN 14082,” and the Methods paragraph carries a parenthetical noting that the PDF specifies “non-flame AAS” while PN-EN 14082’s non-flame pathway is graphite-furnace.

Wiki pages this source may touch

• lead
• cadmium
• apple
• plums
• strawberries
• raspberries
• grapes
• fresh-fruit
• eu-1881-2006-contaminants-superseded

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.