Dietary patterns and heavy metal exposure in indigenous communities of the northern Peruvian amazon

Background

High heavy metal levels have been detected in environmental samples from Corrientes, Pastaza, Tigre and Marañon river basins in the Northern Peruvian Amazon, as well as in biological samples of the local population. Evidence suggests metal infiltration in the food chain, indicating diet as a key exposure pathway. This study describes dietary patterns and assess associations between food intake and metal levels (Pb, As, Ba, Hg, Cd) in Indigenous communities affected by oil blocks 8 and 192.

Methods

Cross-sectional study of 600 participants (May–June 2016). Diet was assessed using a semi-quantitative Food Frequency Questionnaire (52 items). Blood, urine, and local foods were analyzed for metal concentrations. Intake was described by age (< or ≥ 12 years old). Dietary patterns were identified using principal component analysis. Multivariable linear regression models, adjusted for sex, age, body weight, and basin, evaluated associations between diet and metal levels.

Results

High blood lead levels (BLL) were the main concern (geometric mean 5.21 μg/dL); 47.0% of children and 57.4% of adults exceeded 5 μg/dL. No participants exceeded reference thresholds for urinary As, Ba, Hg, or Cd. Four dietary patterns were identified: Fish; Big mammals & fish; Tubers; Varied animals. In children, BLL was positively associated with fruit, tuber, omnivorous meat intake, and the “Varied animals” pattern (game meat). In adults, carnivorous fish intake was associated with higher urinary Hg, while tuber intake was inversely associated with urinary Cd. Food analysis showed high Pb in Boquichico fish and high Hg in Shuyo fish.

Conclusions

Diet is a significant exposure pathway to toxic metals, particularly Pb and Hg, in these populations. Findings likely reflect long-term environmental contamination from oil extraction and possible lead ammunition use. Culturally appropriate interventions and targeted monitoring are needed to reduce exposure while preserving food sovereignty.

Key messages

• Diet is a key pathway of metal exposure in Amazonian Indigenous communities affected by oil activity, highlighting the need for targeted, culturally appropriate interventions.

• High lead levels and fish-related mercury exposure reveal ongoing environmental contamination, calling for monitoring and actions that protect health while preserving food sovereignty.