Scutarasu and Trincă 2023 — Heavy metals in foods and beverages: global review including edible oils

This narrative review in the MDPI journal Foods covers the global situation of heavy metal contamination across major food groups (fruits and vegetables, dairy, meat, edible oils, alcoholic beverages), with a dedicated section (Section 4.4 and Table 4) on edible oils aggregating concentration data from published studies across multiple countries. The review is broad-scope and should be treated as evidence tier B (secondary synthesis, not original data), but its Table 4 provides a useful cross-oil cross-country heavy metal inventory drawing on A-tier primary studies. The review also provides a useful regulatory summary of Codex Alimentarius limits for As, Cd, Pb, and Hg across food matrices.

Key numbers

Edible oil heavy metal concentrations compiled from literature (Table 4; mg/kg unless noted):

Olive oil:

• Cyprus: Cd 0.05 mg/kg (2019, ref 87)
• Turkey: Cd 0.9922 mg/kg (2021, ref 88)
• Iran: Cd 0.0955 mg/kg (2020, ref 89)
• London: Pb 0.143 mg/kg (2022, ref 94)
• Pakistan: Pb 4.285 mg/kg (2022, ref 95)
• Ukraine: Cu 0.355 mg/kg (2015, ref 96)
• Greece: Cu 0.086 mg/kg (2022, ref 97)

Rice oil:

• Illinois, USA: Cd <0.891 mg/kg (2015, ref 86)

Rapeseed oil:

• Iran: Cd 0.098 mg/kg (2020, ref 89)
• China: Pb 1.96 mg/kg (2016, ref 90)
• Poland: Pb 0.056 mg/kg (2017, ref 91)
• Brazil: Cu 0.81 mg/kg (2015, ref 85)

Sesame oil:

• Iran: Cd 0.0935 mg/kg (2020, ref 89)
• Pakistan: Pb 4.005 mg/kg (2022, ref 95)
• Korea: Pb 36.01 µg/kg; tAs 15.18 µg/kg; Al 15.97 mg/kg (2019, ref 41)

Coconut oil:

• London: Pb 0.158 mg/kg (2022, ref 94)

Linseed oil:

• Poland: Cu 0.10 mg/kg (2016, ref 98)

Flaxseed oil:

• Korea: Pb 25.65 µg/kg; Cd 70.03 µg/kg; tAs 3.1 µg/kg; Al 29,814 µg/kg = 29.81 mg/kg (2019, ref 41)

Canola oil (Monte Carlo):

• tAs 0.062–0.118; Cd 0.097–0.123; Cu 0.027–0.041 mg/kg (2022, ref 92)

Corn oil:

• Turkey: Cd 0.0012; Ni 0.0015; Zn 0.0330 mg/kg (2008, ref 84)
• Iran: Pb 0.099 mg/kg (2020, ref 89)

Corn oil (Monte Carlo):

• tAs 0.095–0.106; Cd 0.018–0.045; Cu 0.027–0.041; Ni 0.024–0.076; Zn 0.613–1.090 mg/kg (2022, ref 92)

Cottonseed oil:

• tAs 0.104–0.116; Cd 0.001–0.008; Cu 0.010–0.062; Ni 0.016–0.078; Pb -0.004–0.016; Zn -0.060–2.148 mg/kg (2022, ref 92)

Soybean oil:

• Turkey: Cd 0.0013; Ni 0.0027; Zn 0.0348 mg/kg (2008, ref 84)
• Salvador, Brazil: Cu 0.83 mg/kg (2015, ref 85)
• Monte Carlo: tAs -0.037–0.125; Cd 0.058–0.129; Cu 0.247–0.283; Ni 0.579–0.677; Pb 0.033–0.070; Zn 0.357–0.588 mg/kg (2022, ref 92)

Sunflower oil:

• London: Pb 0.274 mg/kg (2022, ref 94)
• Iran: Pb 0.099 mg/kg (2020, ref 89)
• Salvador, Brazil: Cu 0.81 mg/kg (2015, ref 85)
• Monte Carlo: tAs -0.019–0.147; Cd 0.024–0.038; Cu -0.026–0.233; Ni 0.153–0.221; Pb 0.022–0.025; Zn 0.411–0.456 mg/kg (2022, ref 92)

Regulatory limits summarized (Codex Alimentarius, from text):

• tAs in edible fats and oils: 0.1 mg/kg
• Pb in oils and edible fats: 0.1 mg/kg
• Cd: no Codex limit stated for oils specifically
• Hg: not separately addressed for oils

Methods

Narrative literature review (not systematic, no PRISMA or explicit inclusion criteria). Data in Table 4 is compiled from cited primary studies; the table does not provide the analytical methods used in each primary study. Concentrations reported as published; no conversion or harmonization of units is performed by the reviewers beyond what appears in the original papers. Several negative values appear in Table 4 (e.g., cottonseed Pb -0.004 mg/kg); treat these as anomalous table entries requiring primary-source verification, not as real negative concentrations.

Implications

Certification: The Pakistan Pb entry for olive oil (4.285 mg/kg) and the Turkey Cd entry for olive oil (0.9922 mg/kg) are extreme outliers relative to the other olive-oil values tabulated in this review. These values, if verified against the primary studies, make geographic origin a relevant source-level stratification variable; this review is not itself a sourcing rule or threshold source.

Courses: The review’s toxicology section (Section 2) provides well-organized one-page summaries of the health mechanisms of Pb, Cd, As, Hg, Cr, Co, Ni, and Zn that can inform course module intros.

App: Al in sesame and flaxseed oils (Korea study: 15,970 and 29,810 µg/kg respectively) is an unexpected finding worth tracking. These oils are used in specialty health-food contexts. However, treat with caution: negative Pb and As values in some rows of Table 4 indicate methodological issues in at least one of the underlying studies.

Speciation caution: All arsenic values in this review should be treated as total arsenic; speciation into iAs vs. organic forms is not addressed.

Wiki pages this source may touch

• olive-oil
• soybean-oil
• sunflower-oil
• rice-bran-oil
• rapeseed-oil
• sesame-oil
• corn-oil
• coconut
• vegetable-oils
• olive-oil
• cooking-oils-other
• lead
• cadmium
• arsenic-total
• nickel
• chromium
• mercury-total
• aluminum
• copper
• zinc
• codex-cxs-193-1995

Verification notes

• Cross-vendor audit (Codex, 2026-05-17) corrected multiple Table 4 metal/product transpositions, expanded metal and ingredient scope for the edible-oil section, replaced narrow oil-specific matrix terms with broad oil matrices, and reframed olive-oil origin language as source-level stratification rather than a sourcing rule.
• 2026-05-25 manual-fetch re-ingest: added the two Table 4 rows previously omitted from Key numbers — Coconut oil (London Pb 0.158 mg/kg, 2022, ref 94) and Linseed oil (Poland Cu 0.10 mg/kg, 2016, ref 98). Declared products: [olive-oil, cooking-oils-other] so the routing layer fans this source out to the HMTc-locked oil rows it actually bears on; the prior empty products: [] left the source flagged advisory-malformed and producing zero product-page routes despite covering both Cat 7 Row 1 (olive oil) and Cat 7 Row 2 (other cooking oils) directly.
• Fresh-context audit subagent (2026-05-25) flagged “Rice bran oil” Key numbers heading as a recharacterization of the PDF table label “Rice oil”; verified against PDF Table 4 (p. 13) and corrected to “Rice oil.” The frontmatter ingredient slug remains rice-bran-oil because ref [86] (the underlying Illinois 2015 primary study) is rice-bran-oil-specific; the table-row label tracks the review, the ingredient routing tracks the primary study.
• Fresh-context audit subagent (2026-05-25) flagged [[regulations/codex-cxs-193-1995]] as missing from the taxonomy snapshot. Verified: the slug is used by four other source pages in this corpus (hernandez-montoya2026, dearing2025, sarker2022, this page) as the established convention for the broader CXS 193-1995 contaminants standard. The existing wiki/regulations/codex-cxs-193-1995-tin-canned-foods.md is the same standard but narrowly titled to its tin rows. Link is retained pending Karen’s resolution (either rename the existing regulation page or split a general CXS 193 page from it); this re-ingest does not silently rewrite established corpus convention.
• The review reports arsenic and mercury without species separation; this page treats those entries as total arsenic (tAs) and total mercury (tHg).
• Negative concentration entries are reproduced only because they appear in Table 4; primary-source verification is required before interpreting them quantitatively.

Page history

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