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.

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.

Chile is an important producer of copper, and it has serious soil contamination problems, mainly related to mining activities. A typical example is the Aconcagua River basin, which has been the scene of large-scale mining operations throughout history, making it critical to analyze due to the high concentrations of heavy metals in its soils. The objectives of this study are (1) to assess the level of As, Cu, Pb, and Zn contamination in the surface soil ecosystem based on different environmental indexes and (2) to determine the health risks of adults and children located in watersheds of the Aconcagua and Casablanca Rivers. A database of the Aconcagua River and Casablanca River basins is used to achieve the objectives. From the Aconcagua River basin, 20 topsoil samples from agricultural sectors without mining activity and 127 topsoil samples from sectors with mining activity were selected. On the other hand, thirty-five topsoil samples of the Casablanca River basin, without mining activity, were analyzed. The evaluation of soil contamination was done using environmental indexes. Finally, carcinogenic and noncarcinogenic risks to humans were calculated using the USEPA model. The mean concentration of chemical elements in the Aconcagua River basin for samples without mining presence was As 10.55 mg kg⁻¹, Cu 85.75 mg kg⁻¹, Pb 26.65 mg kg⁻¹, and Zn 139.5 mg kg⁻¹. The correlations show that the elements As, Cu, Pb, and Zn come from anthropogenic sources, which are also enhanced by the geogenic origin of Cu and Zn. The spatial distribution of the analyzed elements shows a spatial pattern that extends across industrial areas and emission sources, with higher concentrations of As, Cu, Pb, and Zn identified near mining areas of the Aconcagua River basin. The upper limit of the geogenic values determined by the MAD (median absolute deviation) method for the Aconcagua River basin without mining presence was 14.5 mg kg⁻¹ for As, 94 mg kg⁻¹ for Cu, 37.5 mg kg⁻¹ for Pb, and 194 mg kg⁻¹ for Zn. Finally, the geoaccumulation index, contamination factor, integrated contamination index, and potential ecological risk registered exceptionally high contamination in some soil samples, especially in areas with mining influence. It is essential to highlight that there are non-carcinogenic risks related to As, Cu, and Pb, a hazard quotient (HQ) higher than 1, and acceptable carcinogenic risks between 1.0 × 10⁻⁶ and 1.0 × 10⁻⁴ to As and Pb in children and adults in the Aconcagua River basin.

This study presents a novel approach that integrates Discrete Event Simulation (DES) with Design of Experiments (DOE) techniques, framed within a stochastic optimization context and guided by a multi-objective goal programming methodology. The focus is on enhancing the operational efficiency of an emergency department (ED), illustrated through a real-world case study conducted in a Chilean hospital. The methodology employs Response Surface Methodology (RSM) to explore and optimize the impact of four critical resources: physicians, nurses, rooms, and radiologists. The response variable, formulated as a goal programming function, captures the aggregated patient flow time across four representative care tracks. The optimization process proceeded iteratively: early stages relied on linear approximations to identify promising improvement directions, while later phases applied a central composite design to model nonlinear interactions through a quadratic response surface. This progression revealed complex interdependencies among resources, ultimately leading to a local optimum. The proposed approach achieved a 50% reduction in the aggregated objective function and improved individual patient flow times by 7% to 26%. Compared to traditional metaheuristic methods, this simulation–optimization framework offers a computationally efficient alternative, particularly valuable when the simulation model is complex and resource-intensive. These findings underscore the value of combining simulation, RSM, and multi-objective optimization to support data-driven decision-making in complex healthcare settings. The methodology not only improves ED performance but also offers a flexible and scalable framework adaptable to other clinical environments seeking resource optimization and operational improvement.

Arsenic (As) and mercury (Hg) are trace elements of major environmental and public health concern. Their relevance is due to their well-documented toxicological effects. In rapidly urbanizing port-industrial cities, soil contamination by these elements represents a critical challenge. This situation compromises sustainable urban development and environmental governance. This study had three main objectives: First, to evaluate the contamination status of As and Hg in urban soils using multiple geochemical indices; Second, to assess the potential human health risks associated with exposure in the urban environment of Talcahuano; Third, to identify the relative contributions of geogenic and anthropogenic sources based on spatial distribution patterns. A total of 420 soil samples were collected. These included 140 topsoil samples (TS; 0–10 cm), 140 subsoil samples (SS; 10–20 cm), and 140 deep-soil samples (DS; 150 cm). Arsenic concentrations were determined using hydride-generation atomic absorption spectrometry (HG-AAS). Mercury concentrations were measured by cold-vapour atomic absorption spectrometry (CV-AAS). Median As concentrations were 2.7 mg kg⁻¹ in TS, 3.1 mg kg⁻¹ in SS, and 2.5 mg kg⁻¹ in DS. The corresponding median Hg concentrations were 0.2 mg kg⁻¹ in TS and 1.4 mg kg⁻¹ in both SS and DS. Spatial distribution maps were generated through ordinary kriging interpolation. Geochemical baseline values were calculated using the median + 2 × MAD approach. The resulting baseline values were 7.8 mg kg⁻¹ for As and 3.6 mg kg⁻¹ for Hg. Contamination assessment was conducted using the geoaccumulation index (Igeo), enrichment factor (EF), and contamination factor (Cf). Results indicate that most soils are classified as uncontaminated. Enrichment levels were minimal and contamination factors were low. Nevertheless, isolated outliers were identified. These included one significantly enriched As sample and several moderately enriched or slightly contaminated Hg samples. Human health risk assessment incorporated the Hazard Index (HI) and Total Carcinogenic Risk (TCR). Results indicate that neither non-carcinogenic nor carcinogenic risks exceed acceptable thresholds at any investigated soil depth. Spatial analysis suggests that anthropogenic activities are the dominant sources of As and Hg in the study area. Traffic emissions and industrial activities appear to be the primary contributors.