Mercury contamination in Peruvian Amazon insects linked to gold mining, study finds

A recent study published in *Nature* sheds light on how mercury from gold mining accumulates in insects across the Peruvian Amazon, highlighting the ecological risks posed by this toxic metal. Researchers analyzed 492 insects from nine taxonomic groups in three locations with varying levels of mining activity: the pristine Cocha Cashu Biological Station in Manu National Park, the moderately affected Los Amigos Biological Station near mining corridors, and the heavily degraded Linda-2 mining concession in La Pampa, where mercury use is intensive. ## Mercury bioaccumulation varies by diet and location The study found that mercury accumulation in insects depends not only on their habitat but also on their diet. Necrophagous insects, which feed on carrion, exhibited mercury levels up to **39 times higher** than herbivorous species. Additionally, insects in La Pampa had mercury concentrations **up to 7 times greater** than those in the protected Cocha Cashu area. Some species, like the scarab beetle *Coprophanaeus telamon*, showed extreme contamination, with mercury levels **24 times higher** in the most polluted site compared to the cleanest. ## Insects as key mercury vectors in ecosystems The research also underscores the role of insects as biological intermediaries, transferring mercury from the environment to other organisms in terrestrial ecosystems. Lead researcher Elena Chaboteaux emphasized their ecological importance, stating that insects are foundational to forest ecosystems. This study is the first to document mercury contamination in terrestrial Amazonian insects across a trophic gradient, whereas previous research focused primarily on aquatic systems and fish. Chaboteaux explained in an interview with *Mongabay Latam* that insects were chosen for their ubiquity and ease of identification in the rainforest. The findings raise concerns about broader ecological impacts, as mercury-particularly its highly toxic form, methylmercury-can move up the food chain, affecting predators and potentially humans who consume wildlife.