Mercury and lead detected in mangrove crabs of Paraná, Brazil

Researchers from the marine biodiversity program Rebimar and the State University of Paraná examined the caranguejo‑uçá that lives in the mangroves of the Oceania Bay near Paranaguá. Their analysis revealed the presence of mercury and lead in the crabs, with concentrations varying by site and season. The crabs were observed to be otherwise healthy and capable of normal activity.

The study highlights potential risks for people who consume the crustaceans, especially during the summer harvest period that falls outside the annual defeso protection window. Scientists say further research is needed to assess how much of these metals could accumulate in humans. The local crab fishery, which supports families such as that of longtime catcher Antônio de Souza, generated roughly R$ 9.8 million in 2024, underscoring the economic importance of the species for the Paraná coast.