Hydrogeochemistry of arsenic pollution in watersheds influenced by gold mining activities in Paracatu (Minas Gerais State, Brazil)

Abstract

The aim of this study is to evaluate total arsenic (As) concentrations in drinking water (main pathway of human exposure) and its hydrogeochemical controls in the "Morro do Ouro" gold mine region, which is the largest gold mine in Brazil, characterized by gold-arsenopyrite association. Arsenic concentration was generally below the detection limit (LOD < 0.5 μg L(-1)). Thus, water ingestion may not be a significant exposure pathway to local population. Low groundwater As concentrations (<1 μg L(-1)) are likely due to ore body structural setting, which plunges from 10° to >20°, being readily covered by thick phyllites that are poor in As some hundreds of meters away from the mine. Thirty-five percent of As levels in superficial waters (<0.5 to 40 μg L(-1)) were >10 μg L(-1), which is the maximum permissible value for human ingestion. The highest concentrations were found nearby mine facilities and old artisanal mining areas surrounding the mine, decreasing downstream. Undisturbed watersheds showed As concentrations close to LOD. Hydrogeochemical data stress the sorption (adsorption and co-precipitation) of As role, mainly by Fe oxyhydroxides, as a geochemical filter that retains As, attenuating its concentration in both superficial and groundwater. Such minerals are abundant in the region oxisols, sediments, and phyllites and may form stable mineral complexes with As under the pH (mostly neutral) and Eh (reduced environment) conditions found in the field. It has been demonstrated that As(III) (more toxic) and As(V) co-exist in the analyzed waters and that As(V) predominates in superficial water.

Perception of pollution and arsenic in hair of indigenous living near a ferronickel open-pit mine (Córdoba, Colombia): Public health case report

“…Rather than attempting to associate its presence in the hair of women with health effects, which could be studied by future investigations, these results should be understood as an exploration of different arsenic exposure time frames. The data clearly indicate the presence of the metalloid in concentrations similar to those reported in areas where mines exist [16][17][18] . The case that exceeds the reference value is an indication of the existence of populations with a higher degree of vulnerability, or where episodes have occurred in which arsenic increased due to accidents or disasters in mining areas, such as in Spain 19 and more recently in Mexico 20 and Brazil 21 .…”

Anais do IV Seminário Nacional do Mestrado Profissional em Rede Nacional em Gestão e Regulação de Recursos Hídricos - PROFÁGUA

“…A Primeira Componente Principal -CP1 representa os parâmetros chumbo total, manganês total e níquel total, pois estes elementos apresentaram cargas ativas maiores que 0,6 em módulo, ou seja 0,76, 0,77 e 0,84, respectivamente. Tal característica é explicada pela presença de minerais sulfetados na bacia do rio Paracatu (BIDONE, et al, 2016), que na presença do oxigênio e água, tornam disponíveis no ambiente o chumbo, manganês e níquel . A maior relevância do chumbo, pode ser explicada pela sua exploração nos municípios de Paracatu e Vazante.…”

Evaluation of the Geochemical Behavior and Environmental Risk of Metals in an Area Impacted by Industrial Waste in Queimados (RJ)

“…[1][2][3][4][5] Os metais podem adversamente afetar os seres humanos e animais devido aos impactos à fauna do solo, produção agrícola e a qualidade das águas superficiais e subterrâneas. [4][5][6][7][8][9][10][11][12] A empresa Centro Tecnológico de Resíduos S/A (CENTRES) operou no atual município de Queimados (RJ) um pátio de estocagem provisória de resíduos industriais perigosos (Classe I), entre 1987 e 1998. Estes resíduos seriam armazenados somente até a construção pela CENTRES do primeiro aterro de resíduos industriais do Estado do Rio de Janeiro.…”