Study on Mercury Methylation in the Amazonian Rivers in Flooded Areas for Hydroelectric Use

Author(s)

Gomes, Vinicius M. ^[1] ; dos Santos, Ademir ^[2] ; Zara, Luiz F. ^[3] ; Ramos, Dayana D. ^{[4, 5]} ; Forti, Juliane C. ^[6] ; Ramos, Diovany D. ; Santos, Felipe A. ^[6]

Affiliation

^[1] Univ Western Sao Paulo Unoeste, R Jose Bongiovani 7000, BR-19050920 Presidente Prudente, SP - Brazil

^[2] Sao Paulo State Univ UNESP, Inst Chem, R Prof Francisco Degni 55, BR-14800060 Araraquara, SP - Brazil

^[3] Univ Brasilia UnB, Univ Area 01 Vila Nossa Senhora Fatima, BR-73300000 Planaltina, Go - Brazil

^[4] Fed Inst Sao Paulo, R Othon Guedes Jr 175, BR-17607220 Tupa, SP - Brazil

^[5] Univ Fed Mato Grosso do Sul, Sch Educ, Ave Costa & Silva, BR-79070900 Campo Grande, MS - Brazil

^[6] Sao Paulo State Univ UNESP, Sch Sci & Engn, Rua Domingos da Costa Lopes 780, BR-17602496 Tupa, SP - Brazil

• Document type: Journal article
• Source: WATER AIR AND SOIL POLLUTION; v. 230, n. 9 SEP 2019.
• Web of Science Citations: 0

Abstract

This study aimed to estimate in laboratory the temporal production of methylmercury during the filling of reservoirs of hydropower plants and to correlate it to the ecosystem of different locations in northern Brazil: Jirau hydropower plant in the Madeira River in the state of Rondonia (white waters-under construction), Cana Brava hydropower plant in the Tocantins River in the state of Goias (clear waters-completed), and the Negro River in the Amazon (black waters-comparative). After collecting water, soil, and sediment samples in the regions mentioned, a microcosm was created to reproduce the conditions close to those found in nature. Water/soil/Hg-0/Hg2+ and water/sediment/Hg-0/Hg2+ were added to glass recipients. Next, methylmercury concentration was monitored by atomic fluorescence spectrometry, total organic carbon by TOC 5000A, and physical and chemical parameters such as pH, redox potential, and dissolved oxygen, for 25 days. The results obtained allow concluding that organic matter plays an important role, providing excess methyl groups to react with inorganic Hg and form organic Hg. The Negro River, which has higher contents of organic matter in its soil, water, and sediment, presented higher potential of mercury methylation in both experiments performed, followed by rivers Madeira and Tocantins. (AU)

• FAPESP's process: 18/18693-6 - Metalloproteomic study of biomarkers of mercury exposure in breast milk samples from the Amazon region - Brazil.
• Grantee: Felipe André dos Santos
• Support Opportunities: Regular Research Grants