Resumo

MEJIA-GONZALEZ, Miguel Ángel et al. Mechanisms that release arsenic to the groundwater of the Laguna Region, states of Coahuila and Durango, Mexico. Tecnol. cienc. agua [online]. 2014, vol.5, n.1, pp.71-82. ISSN 2007-2422.

In order to elucidate the processes that causes high concentrations of arsenic in the aquifer of the Comarca Lagunera were conducted geochemical studies of groundwater and sediment. The results of the sediment geochemistry indicate that arsenic is mainly adsorbed on amorphous and crystalline Fe oxides. The results of the groundwater geochemistry indicate: 1) Cation Exchange between calcium and sodium, 2) Dissolution of calcite due to cation exchange, 3) Increase in pH due to the dissolution of calcite, and 4) high concentrations of arsenic due to elevated pH values.

Palavras-chave : groundwater; sediment; arsenic; Fe oxides; pH.