Overview
This study characterises trace element concentrations in soils and rice grains from the Baixo Vouga Lagunar (BVL), a coastal lagoon agriculture zone in northern Portugal, with analytical focus on arsenic (total), lead, and uranium alongside copper. Five rice grain samples were analysed by ICP-MS: three annual harvests of white Carolino variety (2020, 2021, 2022), one wild-rice sample, and one brown-rice sample. All grain concentrations fell well below European Commission regulatory limits, though soil enrichment factors revealed legacy anthropogenic loading of As, Pb, and U in the agricultural soils.
Key numbers
Rice grain concentrations (ICP-MS, µg/kg dry weight, n=5 samples; values extracted from Table 4 / results section):
| Analyte | Range across samples | Regulatory limit (EC) |
|---|---|---|
| tAs | not individually tabulated per grain variety — reported as below EC limit (200 µg/kg for rice) | 200 µg/kg (white rice, EC 2023/465) |
| Pb | below EC limit | 200 µg/kg (rice, EC 2023/915) |
| U | below EC limit | no harmonised EC food limit at time of publication |
Soil concentrations (mg/kg) showed As enrichment factors up to ~3× background in some paddy plots; Pb and U similarly elevated relative to geochemical background, attributed to historical industrial activity and agricultural inputs in the BVL catchment.
Methods (brief)
Analytical method: ICP-MS (total digestion of rice grain and soil samples). Speciation: total arsenic (tAs); no HPLC speciation performed — inorganic arsenic fraction not reported. Sample preparation: microwave acid digestion. LOD/LOQ: not explicitly stated for grain matrix. Quality control: certified reference materials used for soil; grain QC details limited.
Limitation: very small grain sample set (n=5); no statistical range across field plots. Results are indicative of this specific agroecosystem and should not be generalised to Portuguese or Carolino variety rice broadly.
Implications
Certification: tAs values are below EC limits but the paper does not report numeric grain concentrations explicitly; cannot extract ppb values for use in concentration distributions. Useful as geographic context for European paddy rice rather than as a Path A concentration dataset.
Courses: illustrates soil-to-grain transfer pathways and the role of flooded paddy conditions in As accumulation; useful for supply-chain module.
App: rice-grain tAs, Pb, U matrices confirmed present but no extractable numeric grain concentrations for contamination_profile update; status remains data-gap for numeric synthesis.
Microbiome: not applicable.
Related evidence
Update history
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