Cadmium bioaccumulation and gastric bioaccessibility in cacao: A field study in areas impacted by oil activities in Ecuador.
Level 4 - case-series / case-control
Cross-sectional environmental field study with in vitro bioaccessibility testing (assigned by design analogy)
PubMed 28781181 · doi:10.1016/j.envpol.2017.07.080
What was done
Cadmium (Cd) concentrations were measured in soil layers (0–20 cm topsoil and deeper layers), cacao leaves, pod husks, and beans from 31 farms located in northern Amazon and Pacific coastal areas of Ecuador exposed to oil activities, compared to two control areas. In vitro human gastric bioaccessibility of Cd was measured in raw cacao beans and cacao liquor samples to evaluate potential health risks.
What was found
Topsoil Cd concentrations exceeded the Ecuadorian legal threshold at 39% of sampling sites and were higher than concentrations in deeper layers. Leaves accumulated more Cd than husks or beans, but 50% of sampled beans still exceeded 0.8 mg/kg. In vitro gastric bioaccessibility of Cd reached up to 90% in beans and liquor, leading the authors to assess health risk as low to moderate. Root-to-cacao transfer was governed by soil properties, farming practices, and potential volcanic inputs, and bean Cd levels did not correlate as a tracer for oil industry activities.
Why it matters
This study shows that cadmium accumulation in Ecuadorian cacao frequently exceeds European regulatory limits for dark chocolate and is highly bioaccessible, but stems from natural and agricultural factors rather than local petroleum operations.
Limits
Human exposure risks rely on in vitro gastric bioaccessibility models rather than in vivo absorption or biomonitoring data. The abstract provides percentage exceedances but omits precise absolute cadmium concentrations, variance measures, and exact sample counts per tissue type.
Cited by
- supports Cacao plants bioaccumulate heavy metals from the soil into cacao beans.