# Unexpected High Blood Lead Levels in a Remote Indigenous Community in the Northeastern Peruvian Amazon

## TL;DR

A remote Indigenous community in the Peruvian Amazon has unexpectedly high lead levels in blood, likely due to lead-based ammunition and contaminated water.

## Contribution

This study identifies Pb-based ammunition and river water as the main sources of lead exposure in a non-industrialized Amazonian community.

## Key findings

- Median blood lead levels were 11.74 μg dL−1, with over 94% of children and adults exceeding 5 μg dL−1.
- Isotopic analysis links lead exposure to river water (97.6%) and Pb-based ammunition (78.7%).
- Wildlife and fish transport lead from water and ammunition, contributing to human exposure.

## Abstract

Recent studies suggest that Pb-based ammunition could be an important route of Pb exposure for Indigenous Peoples in tropical rainforests. We analyzed blood lead levels (BLL) and isotopic signatures in 111 humans, 97 wild animals, 81 fish, and potential environmental Pb sources in an Indigenous community in the remote and well-preserved Peruvian Amazon with no history of industrial activity. Median BLL was 11.74 μg dL−1, with BLL ≥ 5 µg dL−1 in 95.8% children <12-yo and 94.5% adults. Pb concentrations in wild animals were 7.00 ± 22.40 mg kg−1 DW in liver, 0.06 ± 0.09 mg kg−1 DW in fish muscle tissues, 17.1 ± 10.8 mg kg−1 in soils and 3.4–3.8 mg L−1 in the main river, although 0.43-0.53 mg L−1 were the Pb levels in decanted water used for drinking and cooking. The similarity of isotopic signatures (207/206Pb and 208/206Pb) shows that the main Pb sources for humans are river waters (97.6%) and Pb-based ammunition (78.7%). Fish and wildlife act as Pb transporters from water, and wildlife act as Pb transporter from ammunition. Evidence of high human BLL in a remote, non-industrialized Amazonian area demonstrates the urgency of designing regional policies that include health prevention measures, focused on drinking water filtration systems and the use of non-toxic, Pb-free ammunitions.