Fonge et al. 2021 - metals in cabbage and carrot from Santa, Cameroon

Fonge and colleagues measured total arsenic, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead, and zinc in cabbage heads and carrot roots grown in Santa, North West Region, Cameroon. The study is occurrence evidence for edible vegetable crop concentrations and supply-chain context for soil-to-crop transfer in farms using irrigation water and agrochemical inputs. The arsenic result is total As; the paper does not report inorganic arsenic speciation, Cr-VI, or mercury.

Key numbers

All edible-crop values below are from Table 14, reported in mg/kg on the paper’s dry-matter basis. Soil values are supply-chain context only and should not be pooled as product concentrations.

The abstract repeats the headline exceedance pattern as tAs 0.51 mg/kg in cabbage and 0.38 mg/kg in carrot, Co 1.41 mg/kg and 1.39 mg/kg, and Pb 1.36 mg/kg and 1.31 mg/kg, respectively. The Results section states that Fe had the highest vegetable concentration across sites, ranging from 3.77 mg/kg to 302.31 mg/kg, while Cd had the lowest range, 0.12 mg/kg to 0.19 mg/kg.

Table 10 reports paired soil context for the same production system: cabbage soils tAs 1.16 mg/kg, Cd 0.87 mg/kg, Co 2.04 mg/kg, Cu 4.61 mg/kg, Cr 9.70 mg/kg, Fe 841.40 mg/kg, Mn 27.10 mg/kg, Ni 2.29 mg/kg, Pb 3.03 mg/kg, and Zn 11.47 mg/kg; carrot soils tAs 1.55 mg/kg, Cd 0.91 mg/kg, Co 2.19 mg/kg, Cu 4.65 mg/kg, Cr 10.07 mg/kg, Fe 843.93 mg/kg, Mn 45.68 mg/kg, Ni 2.27 mg/kg, Pb 3.08 mg/kg, and Zn 9.16 mg/kg.

Transfer-factor context (Table 11): the mean TF across sites was highest for Co, 0.70 in cabbage and 0.64 in carrot; Fe was the lowest, 0.10 in cabbage and 0.02 in carrot. Table 15 reports Health Risk Index values greater than 1 only for Co: 2.31 in cabbage and 2.26 in carrot; all other listed metals had HRI below 1.

Methods (brief)

Samples were collected from four villages in Santa: Mbei, Akum, Moforbe, and Matazem. At each site, one cabbage farm and one carrot farm were selected; mature cabbage heads and carrot roots were collected in triplicate, washed, rinsed with distilled water, sliced, and oven-dried to constant weight at 40 °C. Soil samples were collected from 0-15 cm depth in the same production plots. Soil metals were extracted with aqua regia and measured by ContrAA 300 atomic absorption spectrometry; plant metals were digested with HNO3 in a microwave and measured with a Perkin Elmer 3000 ICP-MS. Two reagent blanks were included in each batch, and all samples were analyzed in duplicate.

Implications

Certification: This page contributes Cameroon soil-to-crop occurrence evidence for cabbage and carrot on dry-matter basis. The crop concentrations should remain jurisdiction- and production-system-aware because the study focuses on Santa farms with irrigation and agrochemical-use context, not a broad retail-market sampling frame.

Courses: The study is useful for separating edible-crop values from soil context, transfer factors, and risk-index calculations. It also illustrates why total arsenic from a vegetable occurrence paper should not be silently treated as inorganic arsenic.

App: The source can support leafy-vegetable and root-vegetable profiles for tAs, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn with a Cameroon growing-region note.

Wiki pages this source may touch

• leafy-vegetables-other
• root-tuber-vegetables
• cabbage
• carrot
• carrots
• leafy-vegetables
• root-vegetables
• vegetables
• arsenic-total
• cadmium
• cobalt
• chromium
• copper
• iron
• manganese
• nickel
• lead
• zinc

Verification notes

• Identity checks on 2026-06-09: DOI 10.1080/27658511.2021.1909860, raw handle MFK_fonge2021, and cite-key fonge2021-cabbage-carrot-metals-cameroon returned no existing source page hits before creation.
• All Key numbers values were re-checked against /tmp/hmi-june9-094.txt extracted with pdftotext -layout, including Tables 10, 11, 14, and 15 and the abstract statement. Units are copied as mg/kg and not converted.
• Speciation check: As is reported as total As (tAs) by the source. The paper does not report inorganic arsenic, Cr-VI, methylmercury, or total mercury.
• Soil-context firewall: soil values are recorded only as supply-chain context and are not described as product occurrence values.
• Closed vocabulary check: all product, ingredient, metal, and jurisdiction slugs used in frontmatter or wiki-page links are present in docs/gpt-collaboration/taxonomy-snapshot.md or established source-page jurisdiction codes.

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.