Overview
- Scientists led by the Omacha Foundation are briefly capturing endangered pink river dolphins near Puerto Nariño to assess health as sentinel species.
- Measurements reported by the team show mercury in some dolphins as high as 42 milligrams per kilogram, far above the 1 mg/kg safety benchmark.
- Fieldwork includes ultrasounds, bacterial swabs, and blood and tissue sampling, with microchips implanted to monitor individuals over time.
- Indigenous communities across the Amazon have recorded elevated exposure, including hair samples above 22 mg/kg in one Colombian group.
- Colombia’s 2018 mercury ban and regional enforcement actions have not stopped illegal mining, while pink dolphin numbers have fallen 52% and gray river dolphins 34% in recent decades.