Findings and scope
The survey measured cadmium in peeled cacao beans and in paired topsoil from 560 trees on 159 farms in 15 provinces of Ecuador, sampled from July to November 2017 (PDF p.5 and p.6). All bean values were above the limit of quantification. Bean cadmium ranged from 0.03 to 10.4 mg/kg dry weight, with an arithmetic mean of 0.90 mg/kg and a geometric mean of 0.55 mg/kg; 254 samples (45%) exceeded the 0.60 mg/kg threshold the authors selected (PDF p.10). The highest values (5.28 to 10.4 mg/kg) all came from one field in the northeast Amazonian region, which the authors link to possible artisanal mining (PDF p.11). Total soil cadmium averaged 0.44 mg/kg (Table 1, PDF p.28). Soil properties (total soil cadmium, pH, organic carbon and oxalate-extractable manganese) explained 65% of the variation in bean cadmium (Table 2, PDF p.29). Only cadmium is reported.
Key numbers
Cadmium, mg/kg dry weight, as printed.
| Measure | Peeled bean | Topsoil (aqua regia) |
|---|---|---|
| n | 560 | 559 |
| Arithmetic mean | 0.90 | 0.44 |
| Geometric mean | 0.55 | not printed |
| Median | not printed | 0.33 |
| 5th to 95th percentile | 0.12 to 3.19 | not printed |
| Range | 0.03 to 10.4 | 0.02 to 6.90 |
Bean sources: PDF p.10 text. Soil source: Table 1, PDF p.28.
By cultivar, the uncorrected geometric mean bean cadmium was 0.56 mg/kg for Nacional and 0.53 mg/kg for CCN-51, not significantly different (Table 3, PDF p.30). After adjustment for soil and agronomic factors the modeled geometric means were 0.57 to 0.61 mg/kg for Nacional and 0.49 to 0.53 mg/kg for CCN-51. By soil order, bean cadmium was lowest on Andisols (0.40 mg/kg) and highest on alluvial soils (0.99 to 1.18 mg/kg); soil cadmium was lowest in Ultisols (0.15 mg/kg) and Andisols (0.23 mg/kg) and highest in alluvial soils (0.41 to 0.67 mg/kg) (PDF p.14).
Methods and Evidence Fitness
Beans were freed of mucilage, dipped for 60 seconds in 0.01 M Na2-EDTA, air-dried, oven-dried at 65 °C and hand-peeled; the nib was ground and digested in nitric acid, and cadmium was measured by ICP-MS (PDF p.7 and p.8). A preliminary test on one batch found 0.84 mg/kg in EDTA-washed beans and 0.90 mg/kg in fermented, dried beans (no significant difference), and 0.73 mg/kg in unwashed beans dried before peeling (PDF p.7). Soils were digested in aqua regia and measured by ICP-MS. The limit of quantification was 0.02 mg/kg dry matter. Recoveries were 100.0 ± 7.0% for NIST 2384 baking chocolate and 99.0 ± 7.5% for BCR-142R soil, with duplicates every 15 samples (PDF p.8 and p.9).
Evidence Fitness is Strong occurrence evidence for the national bean and soil cadmium distribution. The survey is large, uses certified reference materials, and states the dry weight basis. The genotype-adjusted means in Table 3 are model outputs and are recorded as modeled or limited evidence. The beans were not fermented, so the values describe the raw nib rather than traded beans or finished cocoa products.
Assessment limits
Province, region and farm-level values sit in supplementary Tables S1 to S7 and in the maps (Figure 1 and Figure S2), which are not part of this PDF; mapped classes were not read off as values. The number of samples behind the soil-order means is not printed. The text rounds the soil median to 0.3 mg/kg, while Table 1 prints 0.33 mg/kg. Table 1 and the models use n=559, against 560 trees sampled. The Table 3 column header reads “National” for the Nacional cultivar. The 0.60 mg/kg bean threshold is the authors’ working value; the paper states that there are no regulatory limits on cadmium in cacao beans (PDF p.3).
Provenance notes
The PDF (30 pages) was delivered in batch 02 of order HMI-GAP-INGEST-1 on 22 October 2026, filed under the cocoa-butter folder. The SHA-256 matches the batch manifest. The file is the authors’ accepted manuscript, retrieved from the KU Leuven Lirias repository according to the manifest: it is a line-numbered Word document with no journal layout, pagination or DOI printed, so the DOI could not be checked against the PDF. The printed title matches the manifest title apart from capitalisation. Page numbers above are PDF pages, which match the manuscript’s own page numbers.
Related evidence
- Cocoa
- Cadmium
- Cadmium in Cacao from Latin America and the Caribbean: A Review of Research and Potential Mitigation Solutions
- Cadmium fractionation in soils affected by organic matter application: Transfer of cadmium to cacao (Theobroma cacao L.) tissues
- Cadmium isotope fractionation in the soil–cacao system in Ecuador: a pilot study
Update history
22 October 2026: Ingested from the batch-02 PDF. 28 bean and soil cadmium records were added to the evidence register.
Update history
No substantive edit history is available in this build. The full commit record is available in git.