Tropical birds show signs of mercury contamination, due to artisanal gold mining operations: Study

Tropical birds are showing signs of mercury contamination as artisanal and small-scale gold mining operations reach deeper into jungles, finds a new research. Birds living within 7 km of such gold mining activity were found to have mercury concentrations over four times higher than those living at other sites across the tropics of Central and South America, according to the study published on Tuesday in the journal Ecotoxicology.

Tropical birds, from kingfishers to wrens to warblers, are showing signs of mercury contamination as artisanal and small-scale gold mining operations reach deeper into jungles, finds a new research.

Birds living within 7 km (4 miles) of such gold mining activity were found to have mercury concentrations over four times higher than those living at other sites across the tropics of Central and South America, according to the study published on Tuesday in the journal Ecotoxicology.

"It's a wake-up call for bird conservation internationally across the tropics," said lead author Chris Sayers, a conservation biologist at the University of California Los Angeles.

Tropical bird biodiversity has been declining in recent decades, but scientists are not fully sure why. "Based on the levels here, it's reasonable to suggest that mercury may be playing a role," Mr. Sayers said.

Over a 17-year period ending in 2023, dozens of scientists collected thousands of feather, blood and tissue samples from 322 bird species across nine countries in Central and South America and the West Indies, creating the world's largest database to date on mercury concentrations in birds.

The research adds to a growing understanding of how mercury, which is used by gold miners to separate the precious metal from sediment, is impacting wildlife in the tropics.