Evaluation of Heavy Metal Contamination in Soils and Sediments of the Junín National Reserve, Junín, Peru

Lake Chinchaycocha is the second largest lake in Peru and is part of the Junín National Reserve (RNJ), being considered a representative ecosystem for its richness of species and the ecosystem services it provides, so it represents a high ecological and economic value. Since 1936, after the construction of the Upamayo Dam, Lake Junín is subjected to intense anthropic pressure, so the dam creates a barrier that retains the suspended particles of the different heavy metals that are thrown into the river from the headwaters of the San Juan River basin by irresponsible mining companies. Other problems, such as the use of pyrite in the construction of the embankment for the railway, the overexploitation of natural resources, pollution from abandoned mining tailings and the discharge of sewage, and the accumulation of garbage from adjacent villages, have seriously damaged the integrity of the ecosystem. Since 1981, El Niño-Southern Oscillation (ENSO) intensified and, together with other pressures, synergized to catalyze damage to RNJ ecosystems. In the RNJ there are species of indicator plants, including species of the Poaceae and Juncáceae families, which evidence the presence of contamination in the area. In Peru, discharges from mining activity represent the greatest threat to nature. Therefore, the degree of contamination of four heavy metals [As, Cd, Pb, Zn] in soils and sediments from seven contaminated sites was characterized and analyzed. Each metal was designated six strategic points (P.E.) and a reference point (PR). A statistical analysis was made to see the variability of the concentration of the maximum and minimum values and to make a comparison of the values taking into account the environmental quality standards (ECA) for soil in Peru [As, Cd, Pb] and the legal regulations of the Canadian Council of Ministers of the Environment (CCME) in Canada [Zn]. Therefore, it was determined that the Junín National Reserve (RNJ) has high concentrations of the metals Zinc [Zn] and Lead [Pb].