Browsing by Author "Vega, Alejandra"

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    A comparative study of soil metal concentrations in Chilean urban parks using four pollution indexes
    (2022) Vega, Alejandra; Arce, Guillermo; Rivera, Javier I.; Acevedo, Sara E.; Reyes Paecke, Sonia; Bonilla, Carlos A.; Pasten Gonzalez, Pablo Arturo; CEDEUS (Chile)
    Toxic metal enrichment in urban soils from natural and anthropogenic sources is a public health concern thatchallenges sustainable urban development. Active and legacy mining is likely a major contributor of localizedmetal pollution in resource-based economies, although other sources associated with industrial and trans-portation activities may also contribute in urban settings. In mining countries, such as Chile, with no soil qualityregulation, public policies that seek to protect human health should assess metal distribution and pollution in-dexes to guide interventions, especially in urban green spaces. To assess the role of active and legacy miningwaste sites within the urban and peri-urban areas, metal concentrations in the soils of urban parks weremeasured in this study, and four pollution indexes were calculated for four cities of Chile. Copiap ́o and Andacolloin northern Chile represented the cities with several active and legacy mining waste sites located within theurban and peri-urban areas, while conurbation La Serena-Coquimbo and Gran Santiago represented the cities inmining districts that lacked major mining waste sites within their urban perimeters. A total of 82 (Copiap ́o), 30(Andacollo), 26 (La Serena-Coquimbo), and 59 (Gran Santiago) composite surface soil samples were collectedfrom the urban parks. Considering Canadian guidelines for residential/parkland soils, the value for Cu (63 mg/kg) was found to be exceeded in 99%, 50%, 100%, and 97% of samples collected from Copiap ́o, La Serena-Coquimbo, Andacollo, and Gran Santiago, respectively. The guidelines for lead (140 mg/kg) and zinc (250mg/kg) were exceeded in less than 12% of samples collected from Copiap ́o and Gran Santiago. Arsenic was notmainly quantified (<10% quantification frequency, quantification limit = 36 mg/kg). The calculated modifiedpollution load, Nemerow, and soil quality indexes indicated that soils in the urban parks were more polluted incities with urban mine wastes, however, the pollution load index ranked higher metal pollution in Gran Santiago.This study presented the first comparative study of metals in urban parks of Chile, highlighting a large proportionof parks with soil copper concentrations above the international guidelines, while showing higher median values in cities containing urban mine waste disposal sites.
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    Challenges and opportunities for drinking water treatment residuals (DWTRs) in metal-rich areas: an integrated approach
    (2022) Briso, Alejandro; Vega, Alejandra; Molinos Senante, María; Pasten Gonzalez, Pablo Arturo; CEDEUS (Chile)
    The physicochemistry and production rate of drinking water treatment residuals (DWTRs) depends on the raw water composition and the plant operational parameters. DWTRs usually contain Fe and/or Al oxyhydroxides, sand, clay, organic matter, and other compounds such as metal(oids), which are relevant in mining countries. This work proposes a simple approach to identify DWTRs reuse opportunities and threats, relevant for public policies in countries with diverse geochemical conditions. Raw water pollution indexes and compositions of DWTRs were estimated for Chile as a model case. About 23% of the raw drinking water sources had moderate or seriously contamination from high turbidity and metal(loid) pollution If the untapped reactivity of clean DWRTs was used to treat resources water in the same water company, the 73 and 64% of these companies would be able to treat water sources with As and Cu above the drinking water regulations, respectively. Integrating plant operational data and the hydrochemical characteristics of raw waters allows the prediction of DWTRs production, chemical composition, and reactivity, which is necessary to identify challenges and opportunities for DWTRs management.
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    Settling of copper-rich suspended particles from acid drainage neutralization as a function of chemical composition and particle size distribution
    (2022) Montecinos, Mauricio; Briso, Alejandro; Vega, Alejandra; Pasten Gonzalez, Pablo Arturo; CEDEUS (Chile)
    The attenuation of total and dissolved metals from acid drainage (AD) results from the interaction of physical andchemical processes occurring during and after AD neutralization in impacted rivers. Chemical removal occurswhen dissolved metals are transferred into fine particles or flocs, while physical removal occurs when metal-richsuspended particles are deposited from the water column onto the riverbed. Most works studying metal atten-uation in rivers focus on characterizing chemical and physical removal processes separately, yet these processesoften interact and take place concurrently. The fate of copper (Cu) in particle suspensions formed from partialneutralization of AD was studied using a settling column coupled to a device that measured particles size dis-tribution in situ, with minimal floc disruption. Chemical composition, particles size distribution, and total sus-pended solids (TSS) were measured as particles settled. The physical removal of freshly formed particles wasenhanced by aluminum (Al), promoting the formation of larger particles and higher rates of TSS removal.However, Fe promoted higher partition of Cu onto particles, controlling its chemical removal. While the rate ofCu association to particles increased over time, TSS settled out from solution within the initial hour, regardless ofthe chemical composition within the range of tested conditions. Therefore, different remediation strategies maybe applied depending on the goal for removal (e.g., removal of TSS, removal of Cu) and water composition. Thesestrategies must consider chemical conditions (i.e., pH and concentrations of Al and Fe), settling times, and mixingconditions during particles formation for an optimal removal.
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    Toward sustainability and resilience in Chilean cities: Lessons and recommendations for air, water, and soil issues
    (2023) Simon, François; Gironás León, Jorge Alfredo; Rivera, Javier; Vega, Alejandra; Arce, Guillermo; Molinos Senante, María; Jorquera, Héctor; Flamant, Gilles; Bustamante Gómez, Waldo; Greene, Margarita; Vargas Cucurella, Ignacio Tomás; Suárez Poch, Francisco Ignacio; Pastén González, Pablo Arturo; Cortés Arancibia, Sandra; CEDEUS (Chile)
    Achieving sustainability and resilience depends on the conciliation of environmental, social, andeconomic issues integrated into a long-term perspective to ensure communities flourish. Manynations are transitioning toward both objectives, while at the same time addressing structuralconcerns that have not allowed them to look after the environment in the past. Chile is one ofthese nations dealing with such challenges within a particular administrative context, anincreasing environmental awareness, and a set of unique and complex geophysical boundariesthat impose a plethora of hazards for cities, ecosystems, and human health. This paper presentsrecent accomplishments and gaps, mostly from an environmental perspective, on issues related toair pollution, the urban water cycle, and soil contamination, in the path being followed by Chiletoward urban sustainability and resilience. The focus is on the bonds between cities and theirgeophysical context, as well as the relationships between environmental issues, the built environment, and public health. The description and diagnosis are illustrated using two cities as casestudies, Temuco and Copiapo, ´ whose socioeconomic, geographical, and environmental attributesdiffer considerably. Particulate matter pollution produced by the residential sector, drinkingwater availability, wastewater treatment, stormwater management, and soil contamination fromthe mining industry are discussed for these cities. Overall, the case studies highlight how tacklingthese issues requires coordinated actions in multiple areas, including regulatory, information, and financial incentive measures. Finally, the policy analysis discusses frameworks and opportunitiesfor Chilean cities, which may be of interest when conceiving transitional paths toward sustainability and resilience for other cities elsewhere.
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    Water Quality
    (Springer, 2021) Pasten Gonzalez, Pablo Arturo; Vega, Alejandra; Lizama, Katherine; Guerra, Paula; Pizarro , Jaime; Fernández, B.; Gironás, J.