Photochemical Dissolved Gaseous Mercury (DGM) formation/consumption in the Negro River Basin, brazilian Amazon

Journal of the Brazilian Chemical Society

Jardim, Wilson F.¹  Universidade Estadual de Campinas, Campinas, Brazil¹  Universidade Federal de São Carlos, São Carlos, Brazil¹  Instituto Federal de Educação, Ciência e Tecnologia do Maranhão, São Luís, Brazil¹  Fadini, Pedro Sergio¹  Silva, Gilmar Silvério da¹ 

关键词: dissolved gaseous mercury (DGM);    dissolved organic carbon (DOC);    black water;    photolysis.;   

DOI  :  10.1590/S0103-50532009000800023

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

Dissolved gaseous mercury (DGM) formation/consumption was measured during several scientific excursions in the Negro River basin, Amazon, Brazil. Measurements were carried out following diel patterns in both white and black water bodies. In white waters, with pH values around 7 and low dissolved organic carbon (DOC) concentration, mercury saturation prevails during the sunlit period, similar to behavior observed elsewhere. This was attributed to DGM generated by a photoinduced mechanism of Hg2+ reduction. On the other hand, in black waters, with pH around 5 and high DOC values (up to 20 mg L-1), DGM concentration stays below the detection limit during sunlit periods, which was associated to photoinduced Hgº oxidation. Photochemical experiments carried out in situ corroborate the influence of sunlight on DGM formation/consumption. A comparison of diel DGM saturation is presented for both black and white water bodies.

【 授权许可】

Unknown