ECOLOGICA RISK ASSESSMENT OF TRACE ELEMENTS IN THE TAILINGS FROM ANDACOLLO CITY, NORTHEN CHILE

In Chile, metal mining is concentrated between the Administrative Regions IV and VI (which includes the Metropolitan Region). The northern and central zones of the country have abundant copper as well as mineral iodine and iron. Today, these residues are stored in tailing dams. Mine tailings constitute the toxic residues composed of trace elements, which in many occasions are deposited in areas neighboring human settlements and are a health hazard for the inhabitantsIn this work, the concentrations of trace elements such as: Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Zn were studied in 6 sites of the tailings located within Andacollo city, Northern Chile.The sampling points were recorded using GPS geographic coordinates and, in the laboratory, they were characterized determining: pH, electrical conductivity, soluble organic carbon, total organic carbon, available phosphorus, boron, total nitrogen and capacity cation exchange. The concentrations of trace elements in tailings samples, were quantified by atomic absorption spectrophotometry (AAS).Potential anthropogenic hotspots were assessed using indices including enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF), Pollution load index, (PLI), ecological risk (Ei) and potential ecological risk (PERI) index. These indexes are used to assess the presence and intensity of anthropogenic contaminant deposition on surface soil.The physicochemical characterization of the tailings allowed establishing a profile of the environmental conditions of the sampled sites. The sites that presented a higher concentration of metals correspond to sites 4 and 6.The polluted index values than indicated, high degree of contamination for Cu, Hg and Mo by other hand PLI and Ri index indicated the sites more polluted are 4,5 and 6.