Spatial and seasonal variation of arsenic speciation in Pantanal soda lakes

Autor(es)

Hechavarria-Hernandez, Amauris ; Viana, Jose Lucas Martins ; Barbiero, Laurent ; Rezende-Filho, Ary Tavares ; Montes, Celia Regina ; Melfi, Adolpho Jose ; Fostier, Anne Helene

• Tipo de documento: Artigo Científico
• Fonte: Chemosphere; v. 329, p. 9-pg., 2023-04-17.

Resumo

The occurrence of high arsenic concentrations (up to 3000 mu g L-1) in water of soda lakes of the Pantanal wetland is a remarkable case of natural arsenic contamination in South America. However, little is known about arsenic speciation in this environment, particularly regarding speciation changes related to lake trophic status and seasonal variations. To fill this gap, arsenic speciation analysis was carried out in surface (SW) and subsurface (SSW) waters sampled in five soda lakes with different eutrophication status, in two dry and one wet season. As (V) was the dominant species in these waters, while As(III), DMA, MMA and likely complex organic species were present in lower amounts. The results allow to conclude that the arsenic speciation in SW and SSW varies seasonally according to the regional wet or dry periods and lake water levels. In eutrophic turbid and in oligotrophic vegetated soda lakes, arsenic speciation was also characterized by spatial differences between edge and center or between the SW and SSW. Cyanobacteria or macrophytes/algae are involved in arsenic biotransformation in soda lakes through its metabolic and detoxification processes. Significant variation in surface water arsenic speciation occurs as a result of seasonal primary production fluctuation or water arsenic concentration changes in the soda lakes, increasing organoarsenics in dry periods, whereas in flood periods, As (V) prevails. Spatial distribution of arsenic species is significantly impacted by biogeochemical conditions at the water/sediment interface in soda lakes. (AU)

• Processo FAPESP: 19/18124-4 - Fluxos, especiação e biodisponibilidade de arsênio na interface água/sedimento em lagoas alcalinas do Pantanal de Nhecolândia utilizando DGT
• Beneficiário: José Lucas Martins Viana
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 16/14227-5 - Mudanças climáticas e impactos ambientais em áreas alagadas (wetlands) do Pantanal (Brasil): quantificação, fatores de controle e previsão em longo prazo
• Beneficiário: Adolpho José Melfi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 21/14272-9 - Economias circulares: usando DGT para avaliar a cinética de liberação de fósforo em solos tratados com fertilizantes alternativos à base de resíduos
• Beneficiário: José Lucas Martins Viana
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado