Trace metals concentration in condensed water from the atmospheric humidity in the valley of Mexico [Concentración de metales traza en el agua condensada de la humedad atmosforica en el valle de México]

The shortage of drinking water is a serious problem that makes it necessary to seek new options to mitigate it, being atmospheric water harvesting an option. However, it is necessary to ensure the obtained water quality, especially in areas with high levels of air pollution, such as the Valley of Mexico. This study evaluated, in water collected by condensation in the Valley of Mexico, the following variables: electric conductivity (EC) and pH, measured with a conductivity meter/potentiometer; and concentrations of Al, As, Ba, Cd, Cu, Cr, Fe, Hg, Mn, Pb and Zn, determined by an inductively coupled plasma (ICP) spectrophotometer, following the methods recommended by EPA and APHA. The study was conducted in three areas: one in Texcoco, State of Mexico; and two in Mexico City (central and northern areas). In each site, 25 samples were taken from May to August 2010. Water was collected with a prototype called 'Higroiman' (hygro-magnet), which lowers the temperature of the contact surface with environment to induce the dew point and condense the atmospheric humidity. A test of means (Tukey, P?0,05) was applied to the results and these were compared with the permissible limits of drinking water established by WHO. The EC of atmospheric water is between 56,4 and 87,05 S cm-1, while pH values are between 6,58 and 6,63. In some samples, Al, Fe and Pb exceeded the permissible limits

Hydrogeochemistry of salinas Zapotitlan and the crater-lakes Alchichica and Atexcac, Puebla [Hidrogeoqu�mica de salinas Zapotitl�n y los lagos-cr�ter alchichica y Atexcac, Puebla]

In this study we carried on the experimental evaporation of brines from two saline crater-lakes: Alchichica and Atexcac, in the Basin of the Oriental, Puebla, and from a saline spring, Salinas Chiquitas, Zapotitl�n, Puebla, thus documenting patterns of evolution to higher stages of concentration of solutions. In addition 214 low concentration waters were considered which flow in the basins of Puebla, Tlaxcala and Veracruz, to know and compare the hydrogeochemical composition of the solutions analyzed from different geographical areas of Mexico. The experiment of evaporation was carried out under isothermal conditions at 50 �C until complete drying of the system, during this process brine samples were collected in which their anions and cations contents were analyzed, as well as in low water concentration. The three brines are similar in chemical characteristics, they present Na-Cl type solutions, with significant variations in the content of SiO2 and HCO3; meanwhile low concentration waters are HCO3-Ca type solutions. The geochemical developmental pathways that low concentration waters have are mostly first carbonated and second calcium. Meanwhile the brines of the crater-lakes and the saline spring of Zapotitl�n present the direct sulfated route