EVALUATION OF HEAVY METALS CONCENTRATION (AS, PB AND HG) IN IRRIGATION WATER IN AN AGRICULTURAL AREA WITH A MINING HISTORY

Several places around the world have been contaminated by heavy metals mainly due to human activities. Contamination by potentially toxic elements is a serious environmental and human health issue, particularly if contaminated areas are used for food production. Therefore, it is important to determine the heavy metals concentration in different bioindicators. The aim of this work was to evaluate the concentration of As, Pb and Hg in irrigation water, in agricultural area near to closed mining facilities in Zacatecas, Mexico and compare with International Regulations. The study area included approximately 44 hectares and included 9 agriculture zones and the water for irrigation (5 wells, 1 residual, 1 rainwater). Arsenic and lead analysis were carried out using the recommendations of the Environmental Protection Agency. Mercury analysis was made according Mexican standard. The average values of irrigation water the As, Pb, and Hg concentration was 0.158 ±0.049 mg/L, 0.353 ± 0.021 mg/L, and 0.0027 ± 0.0004mg/L, respectively. The presence of these toxic elements in the bioindicators are the evidence required to promote future studies of chemical speciation, to evaluate the bioavailability through the agriculture products, to estimate the risk of exposure, and the relationship with public health.