Diferenciación de la contaminación inorgánica en las aguas subterráneas del valle de la ciudad de San Luis Potosí, S.L.P. México

The Valley of San Luis Potosi has no natural surface drainage. Underneath the valley floor there are volcanic and sedimentary materials forming the aquifer system: a shallow water table aquifer lies over a clay lens which confines a deeper one. Thermal waters are evident in the confined aquifer. Water management of both supply and sewage, plus prevailing hydrogeological conditions gave lead to a groundwater quality survey. Three basic sources of contamination were sought: industrial, whit Fe, Cr, Cu, Zn, Pb and As; sewage (domestic) water, with NO 3 - , CL - and HCO 3 - , and a natural effect of the geological media by means of B and F - . Results thus obtained indicate that contamination processes by the industrial waste waters have not a definite effect on the quality of the groundwater of the aquifer system, as yet. However, domestic sewage waters have contaminated the shallow aquifer. The deeper aquifer shows abnormal levels of fluorite, beyond the drinking water standard, attributed to the natural geological environment. The latter shows a geographical correlation with groundwater temperature.