DINÁMICA DE LA CONCENTRACIÓN DE COBRE, PLOMO, MERCURIO Y ARSÉNICO EN SEDIMENTOS DEL RÍO COPIAPÓ, CHILE

On 16 September 2015, the $Mw$ 8.3 Illapel megathrust earthquake broke the subduction contact of the Nazca plate beneath the South American plate, causing unexpectedly high tsunami waves that strongly impacted the coast along the Coquimbo region in central–northern Chile. Here, we report results from a postearthquake and tsunami survey, evidencing a complex coastal geological response driven by the near coast and near trench seismic patches that ruptured during this event. Systematically, high tsunami run‐ups, up to 10–11 m a.s.l., were measured on the western coast of the Punta Lengua de Vaca Peninsula in front of the near trench rupture patch, whereas tsunami run‐ups up to 5–6 m were measured close to the near coast rupture patch. Detailed measurements conducted in the Coquimbo area revealed tsunami run‐ups systematically higher than 6–6.5 m and up to 7.8 m. Field observations of bleached coralline algae supported by ulterior laboratory experiences were compared with geodetic measurements that evidenced complex and variable alongshore uplift‐subsidence responses of the coast, suggesting a relative consistency with respect to its modern geomorphological configuration. From the analysis of pit dug in the Tongoy area, which was strongly impacted by this last tsunami, we evaluated distinctive sandy layers with benthic foraminifera tests interbedded between alluvial fine sediments, which we interpreted as paleotsunami events dated before 1108 ± 77 C.E., shortly before 1346 ± 50 C.E., and approximately 1473 ± 37 C.E. In addition to the historical massive tsunamis that occurred in 1730, 1877, and 1922 C.E. in central and northern Chile, we interpreted prehistoric tsunamis revealed here as events triggered by large megathrust earthquake ruptures, evidencing the high exposition of these coasts to near fields as well as to distant tsunamis produced along the Chilean subduction margin but also in the pan‐Pacific region.

This preliminary study focuses on three abandoned sites, located in the communes of Temuco, Villarrica, and Lonquimay, in the Araucanía 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 hazardous elements (As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, and Zn). The data analyzed belong to a 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 varied 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 geoaccumulation 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.

En el presente trabajo se estudió la remoción de iones cobre y níquel utilizando cáscaras de maní mediante pruebas en lote en sistemas monocomponente y bicomponente (pruebas de remoción simultánea). En este estudio se evaluó el efecto de las variables pH, tiempo de contacto, concentración de biosorbente, concentración del ión metálico. El resultado mostró que las cáscaras de maní fueron un biosorbente relativamente efectivo para la eliminación de estos iones, alcanzándose remoción que varió entre 4,3% y 68,3% para iones cobre y entre 3,6% y 47,6% para iones níquel. La máxima remoción de los iones cobre y níquel se alcanzó en pH 3. La cinética de adsorción de ambos iones se produce rápidamente durante los primeros 15 minutos lográndose eliminaciones cercanas a 60,0 % para el cobre y 43,0 % para el níquel, no obstante, los valores máximos de adsorción se alcanzan a los 30 minutos (cobre) y 60 minutos (níquel). Se observó que a medida que aumenta la concentración del biosorbente la eliminación de los iones cobre y níquel disminuye levemente. Las pruebas de remoción simultánea mostraron que la eliminación de iones níquel (45,7%) fue inferior que la de iones cobre (69,9%), estos resultados fueron muy similares a los alcanzados en las pruebas individuales de remoción de ambos iones.