Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
Cadmium accumulation in cacao cultivars was investigated to explain why “cadmium accumulation in cacao cultivars” often leads to excessive bean cadmium and to identify cultivar-level levers for mitigation that matter to HTMC. The authors used a long-running grafted cacao trial in northern Honduras (CEDEC-JAS) to quantify how soil cadmium availability, plant part, and genotype affect uptake and transfer into beans. They sampled soils and multiple tissues—rootstocks, scions, leaves, and mature and immature beans—from 11 cultivars grown side-by-side, and then analyzed cadmium via ICP-MS, complemented by LA-ICP-MS mapping of bark versus wood. Key regression models tested contributions of plot-level soil variables versus cultivar identity to tissue cadmium, with special focus on bean loading during maturation.
Who was studied?
The material comprised grafted Theobroma cacao L. trees representing 11 common cultivars planted in parallel rows at FHIA’s CEDEC-JAS station near La Masica, Honduras; three trees per cultivar were sampled where mature pods were present. Soils differed across two adjacent plots (Jardín Clonal and Prueba Multilocal) in pH, texture, and available cadmium, allowing evaluation of soil versus genotype effects. Three cultivars—SPA-9, POUND-7, and IMC-67—underwent intensive within-tree sampling across tissues and developmental stages to resolve allocation during bean maturation and to evaluate cadmium partitioning between bark and wood.
Most important findings
| Critical point | Details |
|---|---|
| Soil availability drives vegetative cadmium, not bean cadmium | Available soil Cd strongly correlated with Cd in rootstocks and scions (R² ≈ 0.56–0.59) and in leaves (R² ≈ 0.46), but only weakly with beans (R² ≈ 0.26), indicating additional physiological control during seed loading. |
| Cultivar is the dominant predictor for beans | Multiple regression assigned most bean Cd variance to cultivar (R² ≈ 0.78), whereas vegetative tissues were explained chiefly by “plot” (soil context) plus minor soil covariates. |
| Adult bean differences are large among cultivars | In deep sampling, POUND-7 had ~40% lower Cd in adult beans than SPA-9 and IMC-67, while immature beans did not differ among these cultivars, implicating cultivar-specific loading during maturation. |
| Bark concentrates more cadmium than wood | LA-ICP-MS showed substantially higher Cd in bark than xylem wood of scions, indicating potential xylem-to-phloem transfer or phloem storage relevant to pod loading. |
| Bean Cd often matches leaf Cd | Contrary to many other reports, bean Cd was similar in magnitude to leaf Cd at this site, emphasizing site/cultivar interactions and non-leaf pathways for transfer. |
| EU limits are exceeded at study site | Mean bean Cd on both plots exceeded the EU 2019 limits for cocoa powder, underscoring compliance risk without cultivar management. |
| Soil factors explaining available Cd | Across locations, available soil Cd was well explained by total Cd, pH, and clay content, clarifying when soil management may help but not fully control bean Cd. |
| Leaves are poor proxies for beans | Bean Cd correlated more with scion/rootstock than leaves, suggesting direct stem/branch contribution to seed loading rather than leaf remobilization. |
Key implications
For regulatory impacts, cadmium accumulation in cacao cultivars shows genetic control of bean loading, so HTMC should incorporate cultivar identity into risk models. Certification requirements should weigh cultivar-specific bean transfer coefficients alongside soil tests. Industry applications include prioritizing low-transfer cultivars such as POUND-7 analogs in high-Cd soils and tracking scion/rootstock combinations. Research gaps include mechanistic xylem-to-phloem transport genes and rootstock genotype effects. Practical recommendations emphasize cultivar screening on-site, verifying beans, not just leaves, and combining soil pH and texture management with cultivar selection.
Citation
Engbersen N, Gramlich A, Lopez M, Schwarz G, Hattendorf B, Gutierrez O, Schulin R. Cadmium accumulation and allocation in different cacao cultivars. Science of the Total Environment. 2019;678:660-670. doi:10.1016/j.scitotenv.2019.05.001
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
