Overview

• This month in Puerto Nariño, researchers captured and examined four pink river dolphins, conducting blood and tissue sampling, ultrasounds, photographic documentation, and microchip tagging.
• Findings show mercury burdens far beyond safety benchmarks, with prior measurements of 16–18 mg/kg and some Orinoco dolphins at 42 mg/kg compared with a 1 mg/kg guideline.
• Scientists warn of additional health threats including antimicrobial resistance, respiratory problems, and possible papilloma virus, while noting mercury’s direct role in mortality remains under study.
• High exposure is also documented in Indigenous communities across the Amazon, with hair samples exceeding WHO thresholds and one Colombian community reporting more than 22 mg/kg.
• Pink river dolphin populations have dropped steeply as illegal mining continues despite Colombia’s ban and action plan, while regional efforts include Brazilian raids and Peru’s seizure of 4 tons of smuggled mercury.