Heavy metals as an indicator of ecological impact of a fragmented land uses, San Luis Potosi, Mexico.

The need to study the presence of heavy metals in the soil lies on their impact as a indicator of environmental pollution. Therefore, it was determined the presence of Cu, Zn, Pb and Cd in soils where plant species were distributed in an ecological corridor. Among the municipalities of Soledad Graciano Sanchez and San Luis Potosi (Mexico), 30 points were established, distributed in five land uses: agricultural, rural residential, trade and services, urban residential and mining. Sampling was conducted from 2009 to 2010 (summer, fall, winter and spring). A significant effect of land use was found in terms of Cu (p = 0.000), Pb (p = 0.043) and Cd (p = 0.010). In the case of Zn both the land use (p = 0.000) and season (p = 0.059) had significant effects. It is emphasized that mining land use presented the highest concentrations of the studied metals and agricultural land use the lowest. The levels of four metals are in the range marked like high by the EPA and other technical sources. The levels of Pb and Cd do not exceed the NOM-147-SEMARNAT-SSA1. These results reflect the indicative potential of the soil and its consideration for future to evaluate the habitat of plant species. These results reflect the potential indicative land use in the assessment of environmental quality, however, requires continued monitoring of heavy metals in the area.