Flood pulse and spatial dynamics of mercury in sediments in Puruzinho lake, Brazilian Amazon

• Published in: Acta amazonica Vol. 44; no. 1; pp. 99 - 106
• Main Authors: de ALMEIDA, Ronaldo, BERNARDI, Jose Vicente Elias, OLIVEIRA, Ronaldo Cavalcante, de CARVALHO, Dario Pires, MANZATTO, Angelo Gilberto, de LACERDA, Luiz Drude, BASTOS, Wanderley Rodrigues
• Format: Journal Article
• Language: Portuguese
• Published: 01.03.2014
• Subjects: Freshwater; Brazil, Amazonas, Madeira R; South America, Amazon R
• ISSN: 0044-5967; 1809-4392

The study was conducted in Puruzinho lake (Humaita, AM) considering seasonal periods of rainy and dry in way to elucidate the flood pulse importance in the deposition, remobilization and distributions of mercury and organic matter in bottom sediments in the Madeira River Basin (Brazilian Amazon). Bottom sediments and soils samples were analyzed for total mercury and organic matter. Mercury concentrations obtained in bottom sediment were 32.20-146.40 ng g' and organic matter values were 3.5 - 18.0%. The main region for accumulation of mercury and organic matter was in the central and deepest lake area In the rainy season there was a greater distribution of Hg and organic matter, mainly controlled by means of income of the Madeira river water during flooding, while the predominant process in the dry season was the remobilization of total Hg due to the resuspension of bottom sediments.Original Abstract: Este estudo foi realizado no lago Puruzinho (Humaita, AM) considerando os perlodos de cheia e seca para investigar a importancia do pulso de inundacao na deposicao, remobilizacao e distribuicao das concentracaes de mercurio e materia organica nos sedimentos de fundo no lago da bacia do rio Madeira, na Amazonia brasileira. As amostras de sedimentos e solos foram analisadas para mercurio total e materia organica. As concentracoes mercurio no sedimento de fundo variaram entre 32,20 e 146,40 ng g super(-1) e as porcentagens de materia organica variaram de 3,5 a 18,0%. A principal regiao de acumulacao de mercurio e de materia organica foi na area central e mais profunda do lago. Na estacao chuvosa ocorreu major distribuicao de Hg e de materia organica controlada principalmenre pelo pulso de inundacao do rio Madeira, enquanto que no perlodo de seca predominam os processos de remobilizacao de mercurio devido a resssuspensao do sedimento de fundo.