Romero-Crespo et al. 2023 — Heavy metals in soils and food crops near Ecuadorean mining area
Romero-Crespo et al. measured As, Cd, Cr, Cu, Ni, Pb, and Zn in soils and food crops (including leafy vegetables, potato, and corn) in an agricultural zone adjacent to active mining operations in Ecuador. The study documents mining-related soil contamination transfer into edible crop portions, with As and Pb showing the most pronounced elevations relative to background concentrations. Ecuador is the highest Cd context for cocoa globally, but this study focuses on a distinct mining-adjacent geographic zone rather than the volcanic Andean cocoa-growing regions, illustrating that Ecuador’s heavy metal burden in agriculture is geographically heterogeneous with mining as a second contamination pathway separate from the volcanic soil Cd pathway.
Key numbers
- As in crops: elevated in leafy vegetables near mining zone; specific values require full-text table extraction
- Pb in crops: elevated in all crop types in mining-proximate fields; leafy vegetables showed highest transfer
- Cd: detected but lower than As and Pb in the mining-adjacent context (in contrast to the volcanic soil Cd driving cocoa contamination in other Ecuadorean regions)
- Soil contamination indices calculated; multiple sites above background for As, Pb, Zn
- Exact sample n not extracted from available pages; multi-site design
Methods (brief)
ICP-OES or ICP-MS (method not confirmed from available pages); soils and food crop samples from mining-adjacent agricultural fields in Ecuador; comparison to Ecuadorean and international soil/food safety standards.
Implications
Certification: Illustrates geographic heterogeneity within Ecuador — the Cd narrative for Ecuadorean cocoa (volcanic soils) is distinct from the As/Pb narrative for crops near mining operations in other Ecuadorean regions. Single-country origin flags are too coarse. Courses: Mining-adjacent agricultural land creates a distinct multi-metal contamination profile (As + Pb + Zn) different from the geogenic Cd profile. Both warrant attention in crop sourcing. App: Ecuador geographic flag should differentiate by crop type and region within the country, not apply uniformly.