ABSTRACT
In the Mexican Altiplano in the last decades, several investigations were performed in order to have a better understanding of the sources, mobility and process that controls arsenic in the groundwaters. In the Cerritos Basin in the State of San Luis Potosí elevated concentrations of arsenic above the Mexican critical value (25 µg/L) were found being of concern to the public health. This study not only deals with the evaporation effect on arsenic concentrations but also for its natural occurrence in igneous rocks. This source is connected to the basin by a karst system pointing to the need of fully understanding all parts of groundwater systems.
