Abstract

SARABIA MELENDEZ, Irma Francisca et al. Irrigation water quality in agricultural soils and crops of San Luis Potosí Valley, México. Rev. Int. Contam. Ambient [online]. 2011, vol.27, n.2, pp.103-113. ISSN 0188-4999.

Due to the little availability of underground water for irrigation use, some farmers from the metropolitan area comprised by the municipalities of San Luis Potosí and Soledad de Graciano Sánchez, S.L.P., México, have opted from some time back to use on the one hand, wells that are located in the deep and shallow aquifers of the valley to irrigate the peri-urban agricultural zone, which has an approximate extension of 5000 hectares, and on the other hand sewage waters from domestic and industrial discharging. This brings about a complex crop production panorama that could also lead to a health hazard due to the presence of fecal coliforms. By means of a random sampling, the current quality of the shallow and deep level aquifer water was analyzed as well as the agricultural soil and produces and forage crop quality at the zone under study. The water, soil and crop samples were analyzed in order to evaluate their chemical characteristics. In the case of water, its microbiological characteristics were also analyzed. It was detected that some water samples exceeded the permissible official mexican standards (DOF 1996) for agricultural use regarding sulfate concentration (SO₄^-2) and electric conductivity, which represents an excess of salts in the water. Also exceeding the official standards, in some cases, are the concentration of fecal coliforms (MPN/100 mL) and total dissolved solids. It was observed that the nitrates are present at high concentrations in the water for irrigation. Metal concentrations in soil were found within the regulation levels. In the case of the crops analyzed, the bromatological analysis showed no excess of metals, since they are found in a sufficient degree. However it is advisable to carryout a wider analysis regarding tracer elements, in water as well as in the soil and crops to observe if other elements that could cause a public health problem exist.

Keywords : irrigation water quality; evaluation of soils and crops.