Distribución multicompartimental y fraccionamiento químico del mercurio en pozas de sedimentación de minas de aluvión abandonadas en un área aurífera del departamento del Chocó

Abstract

Mercury (Hg) is one of the most dangerous pollutants that threatens the health of aquatic ecosystems and human populations in many regions around the world. Artisanal and small-scale gold mining (ASGMs) often releases Hg (approx. 1400 Mg/year) primarily in its elemental form (Hg0), which leads to contamination of the soil and adjacent aquatic systems (rivers, lakes, reservoirs/ponds). Therefore, the abandoned gold mining ponds (AGMPs) at the former gold mining sites are particularly susceptible to high concentrations of Hg in their environmental compartments. In these systems, sediments act as important sinks/sources of Hg. However, some variations in the chemical or physical conditions of the sediments (eg., pH, Eh, OM, texture, Fe, S, Al) will directly cause changes in the distribution, solubility, bioavailability and toxicity of the metals. For example, Hg can be biotransformed to methylmercury (MeHg), a powerful neurotoxin that bioaccumulates and biomagnifies throughout the trophic network. Additionally, in many countries, the AGMPs correspond to common fishing sites for local communities. Consequently, the AGMPs is likely to serve as a bond with the human populations who directly depend on the consumption of fish from the ponds as a primary source of protein, and this process also leads to chronic negative effects on the health of the local habitants.