Solar Radiation Effect on the Complexation Capacity of Aquatic Humic Substances with Metals
نویسندگان
چکیده
Este estudo teve como principal objetivo avaliar o efeito da radiação solar sobre a capacidade de complexação das substâncias húmicas aquáticas (AHS) com as espécies metálicas Al, Cr, CrO4 2e Ni. Microcosmos foram montados com AHS extraídas do Rio Preto com concentração de 5,0 mg L de carbono orgânico dissolvido e diferentes concentrações de metais, sendo expostos à radiação solar in situ. As constantes de estabilidade condicional foram de 2,0 × 10, 1,1 × 10 e 2,6 × 10 para os complexos AHS-Cr, AHS-Ni e AHS-CrO4, respectivamente. Os resultados mostraram que a radiação solar foi responsável por um decréscimo na capacidade de complexação de 15-26% para AHS-Al, 15-72% para AHS-Cr, 12-18% para AHS-CrO4 e de 13-42% para AHS-Ni. Conclui-se que a radiação solar altera a disponibilidade de metais previamente complexados às AHS, tornando-os disponíveis no corpo aquático.
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