Mahmood et al. 2025 - metals in dried fruit from local markets

Mahmood and coauthors measured six heavy metals (Cu, Pb, Cr, Ni, Mn, Fe) in eight dried fruit types purchased from public markets, shops, and shopping centers in Anbar Governorate, Iraq, and assessed compliance against WHO and Codex Alimentarius reference limits. Samples were digested in aqua regia and analyzed by flame atomic absorption spectroscopy. The paper does not name any product brand; fruit types are reported in aggregate by fruit identity (plum, banana, orange, kiwi, mango, quince, apple, fig).

Key numbers

Table 1 reports per-fruit concentrations in mg/kg (≡ ppm; 1 mg/kg = 1000 µg/kg). The same table prints two internally inconsistent values that are flagged in the next sub-section. Wet vs dry weight basis is not specified by the authors; samples were oven-dried after washing prior to digestion, so values are interpreted as on a dry-weight basis. Values below:

• Lead (Pb): five of eight fruits at 0 mg/kg (plum, banana, orange, kiwi, quince); mango 0.002, apple 0.063, fig 0.191 mg/kg. LSD0.05 = 0.0101 mg/kg.
• Copper (Cu): plum 0, banana 0.166, orange 0.110, kiwi 0, mango 0.355, quince 0.259, apple 0.295, fig 0.309 mg/kg. LSD0.05 = 0.0161 mg/kg.
• Chromium (Cr, total): plum 1.483 mg/kg (see source-inconsistency note), banana 2.190, orange 2.934, kiwi 0, mango 1.406, quince 3.225, apple 0.257, fig 0 mg/kg. LSD0.05 = 0.0142 mg/kg.
• Nickel (Ni): five of eight fruits at 0 mg/kg (plum, banana, orange, apple, fig); kiwi 1.412 mg/kg (see source-inconsistency note), mango 1.765, quince 0.336 mg/kg. LSD0.05 = 0.0091 mg/kg.
• Manganese (Mn): plum 0.084, banana 0.164, orange 0.014, kiwi 0, mango 0.168, quince 0.105, apple 0.121, fig 0.110 mg/kg. LSD0.05 = 0.0144 mg/kg.
• Iron (Fe): plum 4.887, banana 3.626, orange 4.654, kiwi 5.329, mango 1.910, quince 4.337, apple 4.419, fig 3.055 mg/kg. LSD0.05 = 0.1022 mg/kg.

Sample-level statistical significance is reported as p-value < 0.05 across all six analytes (ANOVA followed by LSD post-hoc). Reported zeros are likely below-LOD readings rather than true zero concentrations; the paper does not state instrument detection limits.

Source-internal inconsistencies

Two values in Table 1 disagree with the same values stated in the narrative text of the source. The narrative values are used above because they are internally consistent with the LSD precision reported in the same table and with the bar-chart axes in Figures 4 and 5:

• Cr in plum (W1): Table 1 prints 11.483 mg/kg, but §3.3 narrative reads “W1 (1.483)“. Bar chart Figure 4 plots ~1.48 (chart y-axis scales to 4 mg/L). The leading “1” in Table 1 is treated as a typographical artifact.
• Ni in kiwi (Q1): Table 1 prints 11.412 mg/kg, but §3.4 narrative reads “Q1 (1.412)“. Bar chart Figure 5 plots ~1.41 (chart y-axis scales to 2 mg/L). Same artifact pattern.

Downstream pooling must use the narrative-consistent values (1.483 mg/kg Cr in plum; 1.412 mg/kg Ni in kiwi), not the printed table values, until the authors clarify.

Methods (brief)

Dried fruit was washed in distilled water, oven-dried, and ground in a stainless-steel mill. One gram of homogenized powder was digested in 10 mL of aqua regia (30 % concentrated HNO3 / 70 % concentrated HCl) at 100 °C until organic matter was decomposed, filtered, and diluted to volume. The digest was analyzed by flame atomic absorption spectroscopy with an acetylene-air burner and hollow-cathode lamp source; calibration used standards at 0.1, 0.5, 1.0, 1.5, and 2.0 ppm prepared by serial dilution from a certified 1000 ppm stock. Quality control consisted of replicate analysis (≥ 3 per sample) and a procedural blank; no certified reference material is named. Instrument vendor and model are not reported. Statistical analysis was performed in SPSS v27 with ANOVA followed by LSD pairwise comparison at α = 0.05.

Implications

Certification: occurrence evidence for Pb, Cr, Ni, Cu, Mn, and Fe in dried fruit drawn from Iraqi (Anbar Governorate) retail markets, suitable for inclusion in dried-fruit pooling once the table-vs-text typos are flagged in the evidence register. The highest Pb value (fig at 0.191 mg/kg = 191 µg/kg) sits well above the EU 2023/915 maximum level for Pb in dried fruit. Courses: example of single-laboratory market surveillance with a small n per fruit type. App: supports a dried-fruit occurrence record but should not be treated as a representative population estimate given n=1 sample per fruit type and a single geographic origin.

Wiki pages this source may touch

• Dried Fruit
• Fruit
• Lead
• Chromium
• Nickel
• Copper
• Manganese
• Iron

Verification notes

Metadata and DOI verified from PDF first page. Table 1 contains two values (Cr in plum, Ni in kiwi) that disagree with the narrative text in §3.3 and §3.4 respectively; the narrative values are used as the authoritative reading because they are consistent with the LSD precision and bar-chart axes. AAS instrument vendor/model and certified reference material are not reported in the paper; the methods section here reflects only what the source describes. Wet vs dry weight basis is inferred from the sample preparation (samples oven-dried before digestion) but not explicitly stated by the authors. Sample size is one sample per fruit type with ≥ 3 analytical replicates; downstream pooling should treat this as an n=1 population observation per fruit type rather than as a population distribution.

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