Research Outputs
Potential toxic elements pollution status in zones of technogenic impact in central regions of PerĂº
Soil is a component of the environment. An environmental policy should identify the sources of trace metals in the soil and their effects on people and living beings. The concentrations of 29 surface soil samples (0–25 cm) were determined using the methods EPA 3050B. The data were analyzed using simple and robust statistical analysis that allowed for determining geochemical baseline values. Principal component and correlation analyses were performed, which, together with a spatial analysis, allowed us to distinguish between geogenic and anthropogenic sources. The degree of soil contamination was evaluated using different ecological indices, and the health risks to children and adults were calculated using formulas proposed by the United States Environmental Protection Agency (USEPA). The median concentrations of the analyzed elements correspond to Al 17,666 (mg/kg), As 8.7 (mg/kg), Ba 61.4 (mg/kg), Cd 0.17 (mg/kg), Cr 11.3 (mg/kg), Cu 20.5 (mg/kg), Fe 25,953 (mg/kg), Hg 0.06 (mg/kg), Mn 499 (mg/kg), Ni 20.8 (mg/kg), Pb 15.9 (mg/kg), and Zn 60.6 (mg/kg). In the principal component analysis, four factors were identified that explain 70.3% of the variability of the elements, which, together with the correlation analysis, suggest that the origin of the elements is mainly geogenic with some possible anthropic contributions. The elements analyzed in the soil with moderate contamination correspond to As, Cd, and Pb, in addition, As is the only element that indicated a value above the limit for carcinogenic risk in children. The estimated geochemical baseline values correspond to Al 34,734 (mg/kg), As 15.3 (mg/kg), Ba 113 (mg/kg), Cd 0.41 (mg/kg), Cr 33.8 (mg/kg), Cu 42.9 (mg/kg), Fe 46,181 (mg/kg), Hg 0.12 (mg/kg), Mn 1015 (mg/kg), Ni 42.2 (mg/kg), Pb 21.6 (mg/kg), and Zn 121 (mg/kg). 89.7% of the total samples are at a low level of contamination. The carcinogenic risk due to As in children represents 3.4% of the total samples, so it is considered insignificant.
Analysis and evaluation of concentrations of potentially toxic elements in landfills in the AraucanĂa Region, Chile
This preliminary study focuses on three abandoned sites, located in the communes of Temuco, Villarrica, and Lonquimay, in the AraucanĂa Region, Chile. Two of the sites were classified as illegal landfills and one was a former landfill. Seventy-three surface samples were taken, of which 32 were from site S1, 20 were from site S2, and 21 were from site S3. The objectives of this study were (1) to establish the background values of trace metals present in soils through different statistical methods, (2) to determine the level of contamination and possible ecological risks in soils, and (3) to assess the health risk posed to children and adults from potentially haz- ardous elements (As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, and Zn). The data analyzed belong toa report presented by Chile’s National Environmental Centre (CENMA). An evaluation was carried out through a multivariate statistical analysis to determine the type of origin and association of the trace elements, and spatial distribution maps were generated to establish the behavior of the contents of heavy metals present in the sites studied. The background values for sites S1, S2, and S3 were obtained by the median + 2MADdian absolute deviation) method. These values var- ied in the range of 14,702–41,785 mg kg−1 for Al, 0.83–8.9 mg kg−1 for As, 29.2–77.2 mg kg−1 for B, 59.2–143 mg kg−1 for Ba, 10.1–22.8 mg kg−1 for Cd, 18.4–51.2 mg kg−1 for Co, 12.3–38.0 mg kg−1 for Cr, 47.8–76.6 mg kg−1 for Cu, 36,230–64,274 mg kg−1 for Fe, 0.02–0.05 mg kg−1 for Hg, 482–4396 mg kg−1 for Mn, 16.7–19.3 mg kg−1 for Ni, 1.0–17.6 mg kg−1 for Pb, 1.4–28.2 mg kg−1 for Se, 108–258 mg kg−1 for V, and 68.1–145 mg kg−1 for Zn. In terms of ecological risk, the geoaccumu- lation index (Igeo), enrichment factor (EF), and contamination factor (Cf) values for As and Se at site S1, As at S2, and Pb with As at S3 were the main elements indicating the highest contamination levels, as well as a higher number of samples with contaminated content. The Potential Ecological Risk Index (PERI) revealed that on average, there was a moderate ecological risk for S1 and S2 and a considerable ecological risk for S3; the main contributions were generated by As and Hg in S1 and S2, while, in S3, they were produced by Pb and As. In terms of the risk to human health, the risk was higher in children than in adults, with the ingestion route as the main source of risk. For adults, it was found that there was no likelihood that they would develop any adverse non-carcinogenic or carcinogenic health effects. In contrast, children were found to be more likely to sustain adverse health effects. Regarding the non-carcinogenic risk to children, the Co and As samples at S1, S2, and S3, and the Pb at site S3 showed values exceeding the non-carcinogenic-risk limit. Regarding the carcinogenic risk, all three sites studied had Cd samples that indicated a likelihood of children developing cancer from this heavy metal.
Potentially harmful elements pollute soil and vegetation around the Atrevida mine (Tarragona, NE Spain)
Mining activity is one of the main sources to pollute soil, water and plants. An analysis of soil and plant samples around the Atrevida mining area in Catalonia (NE Spain) was preformed to determine potentially harmful elements (PHEs). Soil and plant samples were taken at eight locations around the mining area. The topsoil (0–15 cm) samples were analysed for physico-chemical properties by standard methods, by ICP-MS for Cd, Co, Cr, Cu, Fe, Ni, Pb and Zn, and were microwave-digested. Plant, root and shoot samples were digested separately, and heavy metals were analysed by AAS. Translocation factor (TF), biological concentration factor (BCF) and biological accumulation factor (BAF) were determined to assess the tolerance strategies developed by native species and to evaluate their potential for phytoremediation purposes. Soil pH was generally acid (5.48–6.72), with high soil organic matter (SOM) content and a sandy loamy or loamy texture. According to the agricultural soil values in southern Europe, our PHEs concentrations exceeded the toxicity thresholds. The highest root content of the most studied PHEs appeared in Thymus vulgaris L. and Festuca ovina L., while Biscutella laevigata L. accumulated more PHEs in shoots. The TF values were > 1 in B. laevigata L., but BAF obtained < 1, except Pb. B. laevigata L., and can be considered potentially useful for phytoremediation for having the capacity to restrict the accumulation of large PHEs amounts in roots and Pb translocation to shoots.
Incertidumbre en los caudales de salida de un modelo hidrolĂ³gico semidistribuido
Para una adecuada gestiĂ³n hĂdrica resulta necesario conocer tanto los caudales simulados por un modelo como la incertidumbre asociada con Ă©stos. El presente estudio busca cuantificar la incertidumbre en los caudales simulados por un modelo hidrolĂ³gico junto con la propagaciĂ³n de Ă©sta hacia aguas abajo, producto de incertidumbre en las precipitaciones, para asĂ definir potenciales mejoras en los resultados de un modelo hidrolĂ³gico. Se calibrĂ³ un modelo conceptual semidistribuido y se determinĂ³ la incertidumbre asociada con la estructura y parĂ¡metros, para luego cuantificar la incertidumbre relacionada con una variaciĂ³n porcentual de las precipitaciones en diferentes periodos del año. Como resultado se obtuvo que el efecto de propagaciĂ³n de la incertidumbre hacia aguas abajo es despreciable debido al aumento de la magnitud de los caudales simulados, y que la incertidumbre en las salidas del modelo depende de la incertidumbre en las precipitaciones sĂ³lo en invierno.
Distribution of heavy metals in the commune of Coronel, Chile
Anthropogenic activities often produce different emanations, some of them excessive, producing contamination of the soil, water, and/or air. This article analyzes soil conditions in Coronel, Chile, a commune with a large industrial presence, identifying the sources emitting potentially toxic elements, the degree of soil contamination, and the carcinogenic and non-carcinogenic risks in the area. Ninety-four samples in the study area were analyzed using different methods. Three factors were identified through a principal component analysis (PCA) that explain 83.27% of the variability of the elements. Four factors were identified through the positive matrix factorization (PMF) model, making it possible to identify the polluting sources according to the pattern of elements they contain. The sources of these factors were then identified. The most common elements in the soil with a particularly high degree of contamination are nickel, vanadium, and chromium, the latter of which being the element that poses the greatest carcinogenic and non-carcinogenic risk to children and adults. Additionally, the highest concentrations of chromium and vanadium were identified near industrial areas of the commune.
Analysis of three indirect methods for estimating the evapotranspiration in the agricultural zone of ChillĂ¡n, Chile
Three models for estimating the daily reference evapotranspiration ETo are evaluated in the agricultural zone of ChillĂ¡n, Chile: Penman-Monteith FAO PMF, Prietsley-Taylor PT and Hargreaves-Samani HS. The daily ETo values estimated through these methodologies are compared with the daily values of ETo estimated from pan evaporation ETB data series obtainedfrom meteorological stations of the Universidad de ConcepciĂ³n Campus ChillĂ¡n and INIA Quilamapu, both located within ChillĂ¡n ’s city limits. The comparison and analysis were performed with data covering a span of 13 years (1996 - 2008). Results indicate that the HS method systemically underestimates ETo values, particularly during dry periods. Moreover, differences between the three methods quantified with Root Mean Squared Error RMSE and Relative Differences RD computed for different time periods (1, 3, 7 and 30 days) suggest that the PT method fits better the observations, being more adequate for the agricultural area of ChillĂ¡n - weekly averages yield RMSE of 1.01 mm/day and RD of 32.8%.