Contrasting anthropogenic drivers of mercury bioaccumulation in fish and associated dietary exposure risks in Amazon and Cerrado floodplain lakes.

Authors

Lucas Cabrera Monteiro, Ludgero Cardoso Galli Vieira, José Vicente Elias Bernardi, Ronaldo de Almeida, Cássio da Silva Cabral, Fabrício Barreto Teresa, João Carlos Nabout, Wanderley Rodrigues Bastos

Published in

Environmental geochemistry and health. Volume 48. Issue 10. Jul 14, 2026. Epub Jul 14, 2026.

Abstract

We evaluated total mercury (THg) concentrations in fish from lakes in two major South American river basins: the Madeira River basin in the Western Amazon, impacted by gold mining, deforestation, and wildfires; and the Araguaia River basin in the Brazilian Savanna (Cerrado), where deforestation and wildfires are the main anthropogenic pressures. Total Hg concentrations ranged from 37 to 2473 µg kg^-1 in Puruzinho Lake (Madeira River basin) and from 6 to 1947 µg kg^-1 in floodplain lakes of the Araguaia River basin. Comparisons between river basins revealed significantly higher THg concentrations in the Madeira River basin for detritivorous, carnivorous, and piscivorous fish, whereas no significant difference was observed for planktivorous species. Within both basins, THg concentrations in planktivorous, carnivorous and piscivorous fish were significantly higher than those observed in detritivores. The trophic magnification slope further confirmed Hg biomagnification along the food web, with a higher coefficient of determination in the Araguaia River basin. Estimated weekly intake calculations indicated substantially greater dietary Hg exposure in the Madeira basin under moderate to high fish consumption scenarios, particularly for predatory species. Although Hg concentrations and the associated risks from fish consumption are higher in the Madeira River basin, which has a long history of gold mining, our results highlight land-use change as an important driver of Hg bioaccumulation in fish across Neotropical ecosystems.

PMID:
42446787
Bibliographic data and abstract were imported from PubMed on 14 Jul 2026.

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