Metal-Rich Runoff From Mines Smothers Pacific Lagoon

New Caledonia is a place of contradictions: a haven of biodiversity that also holds a quarter of the world's nickel. A new study reveals the stark environmental cost of this paradox. Research focused on the Voh lagoon shows that mining activities on the nearby Koniambo ultramafic massif—a type of metal-rich rock—are dramatically speeding up natural erosion.

This has resulted in astonishing sediment accumulation rates, reaching 4.5 centimetres per year near the coral reef, a rate up to 18 times greater than the natural background level. The runoff is not just soil; it's a cocktail of elements from different geological sources. Ultramafic laterites, for instance, are responsible for over 91% of the nickel and 75% of the chromium entering the lagoon.

Scientists stress the importance of now evaluating the ecotoxicological risks, to understand what this high-level metal exposure means for the sustainability of this unique marine environment.