Revista internacional de contaminación ambiental
versión impresa ISSN 0188-4999
GUZMAN-COLIS, Guilda et al. Spatial-temporal evaluation of the water quality of San Pedro river in Aguascalientes state, México. Rev. Int. Contam. Ambient [online]. 2011, vol.27, n.2, pp. 89-102. ISSN 0188-4999.
The aim of this study was to evaluate the spatial and temporal variations in the concentrations of organic matter, nutrients, organic pollutants, coliforms and heavy metals from the San Pedro River, which is the main superficial water body of Aguascalientes State. In the course of the river, approximately 90 km through the State, it receives the contribution of 23 water currents and about 96 % of treated and untreated wastewater generated by domestic and industrial sectors (approximately 120 Mm3/year). Water samples were taken from 43 stations, collected during two sampling campaigns, one in the dry season and other after the rainy season; and 23 parameters were analyzed. Defined spatial trends were not observed in any of the parameters evaluated. Except for heavy metals, the studied pollutants showed high concentrations in 95 % of the collection stations in both sampling campaigns (significant temporal variation was not observed). The high levels of organic matter, total nitrogen, detergents and fecal coliforms were especially remarkable. To globally assess the water quality, a global index of water quality (RWQI), based on the methodology developed by the Canadian Council of Ministers of the Environment (CCME) for the Alberta River, was used. According to the IGCA categories, the global quality of the water in the San Pedro River all along the State is generally poor, usually away from their natural condition or desirable characteristics for agricultural use. The IGCA showed a slight increase in sampling sites near the wastewater treatment plant discharges, raising the marginal category.
Palabras llave : water pollution; quality index; spatial variation; San Pedro River.