Examinando por Autor "Chiang, Gustavo"

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    Ecological variation in invasive brown trout (Salmo trutta) within a remote coastal river catchment in northern Patagonia complicates estimates of invasion impact
    (John Wiley and Sons Inc, 2024-01) Bahamonde, Paulina Andrea; Chiang, Gustavo; Mancilla, Gabriela; Contador, Tamara; Quezada-Romegialli, Caudio; Munkittrick, Kelly Roland; Harrod, Chris
    Salmonids were first introduced into the Chilean fresh waters in the 1880s, and c. 140 years later, they are ubiquitous across Chilean rivers, especially in the southern pristine fresh waters. This study examined the brown trout (Salmo trutta) and native taxa ecology in two adjacent but contrasting rivers of Chilean Patagonia. During spring 2016 and spring–fall 2017 we examined the variation in benthic macroinvertebrate and fish community composition and characterized fish size structure, stomach contents, and stable isotopes (δ13C and δ15N) to understand population structure, fish diet, and trophic interactions between S. trutta and native taxa. The native Galaxias maculatus (puye) dominated the fish community (74% of abundance). S. trutta was less abundant (16% of survey catch) but dominated the fish community (over 53%) in terms of biomass. S. trutta showed distinct diets (stomach content analysis) in the two rivers, and individuals from the larger river were notably more piscivorous, consuming native fish with a relatively small body size (<100-mm total length). Native fishes were isotopically distinct from S. trutta, which showed a wider isotopic niche in the smaller river, indicating that their trophic role was more variable than in the larger river (piscivorous). This study provides data from the unstudied pristine coastal rivers in Patagonia and reveals that interactions between native and introduced species can vary at very local spatial scales. © 2023 Fisheries Society of the British Isles.
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    Endocrine Disruptor Impacts on Fish From Chile: The Influence of Wastewaters
    (Frontiers Media S.A., 2021-03) Barra, Ricardo O.; Chiang, Gustavo; Saavedra, Maria Fernanda; Orrego, Rodrigo; Servos, Mark R.; Hewitt, L. Mark; McMaster, Mark E.; Bahamonde, Paulina; Tucca, Felipe; Munkittrick, Kelly R.
    Industrial wastewaters and urban discharges contain complex mixtures of chemicals capable of impacting reproductive performance in freshwater fish, called endocrine-disrupting compounds (EDCs). In Chile, the issue was highlighted by our group beginning over 15 years ago, by analyzing the impacts of pulp and paper mill effluents (PPME) in the Biobio, Itata, and Cruces River basins. All of the rivers studied are important freshwater ecosystems located in the Mediterranean region of Central Chile, each with a unique fish biodiversity. Sequentially, we developed a strategy based on laboratory assays, semicontrolled-field experiments (e.g., caging) and wild fish population assessments to explore the issue of reproductive impacts on both introduced and native fish in Chile. The integration of watershed, field, and laboratory studies was effective at understanding the endocrine responses in Chilean freshwater systems. The studies demonstrated that regardless of the type of treatment, pulp mill effluents can contain compounds capable of impacting endocrine systems. Urban wastewater treatment plant effluents (WWTP) were also investigated using the same integrated strategy. Although not directly compared, PPME and WWTP effluent seem to cause similar estrogenic effects in fish after waterborne exposure, with differing intensities. This body of work underscores the urgent need for further studies on the basic biology of Chilean native fish species, and an improved understanding on reproductive development and variability across Chilean ecosystems. The lack of knowledge of the ontogeny of Chilean fish, especially maturation and sexual development, with an emphasis on associated habitats and landscapes, are impediment factors for their conservation and protection against the threat of EDCs. The assessment of effects on native species in the receiving environment is critical for supporting and designing protective regulations and remediation strategies, and for conserving the unique Chilean fish biodiversity. © Copyright © 2021 Barra, Chiang, Saavedra, Orrego, Servos, Hewitt, McMaster, Bahamonde, Tucca and Munkittrick.
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    Latin America: Knowledge diversity for a sustainable future
    (John Wiley and Sons Inc, 2023-05) Chiang, Gustavo; Umbuzeiro, Gisela; Lo Nostro, Fabiana
    National and international collaboration and the incorporation of perspectives from outside academia are essential parts of a paradigm shift in science and are necessary for a sustainable future. The articles in this special series “Diversity of Knowledge for a Sustainable Future in Latin America” exemplify many of these aspects, showcasing the latest research and environmental policies for the protection of water, soil, and human health related to several pollutants, for example, microplastics, hydrocarbons, metals, and pesticides. Knowledge—built in an environment where communities are participants in this construction and not only subjects—helps promote understanding of the transdisciplinary nature of environmental issues provided by a diversity of traditional and nontraditional participants. Integr Environ Assess Manag 2023;19:613–614. © 2023 SETAC.
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    Levels of persistent organic pollutants (POPs) in the Antarctic atmosphere over time (1980 to 2021) and estimation of their atmospheric half-lives
    (Copernicus Publications, 2023-07-19) Luarte, Thais; Gómez-Aburto, Victoria A.; Poblete-Castro, Ignacio; Castro-Nallar, Eduardo; Hunneus, Nicolas; Molina-Montenegro, Marco; Egas, Claudia; Azcune, Germán; Pérez-Parada, Andrés; Lohmann, Rainier; Bohlin-Nizzetto, Pernilla; Dachs, Jordi; Bengtson-Nash, Susan; Chiang, Gustavo; Pozo, Karla; Galbán-Malagón, Cristóbal J.
    Persistent organic pollutants (POPs) are synthetic compounds that were intentionally produced in large quantities and have been distributed in the global environment, originating a threat due to their persistence, bioaccumulative potential, and toxicity. POPs reach the Antarctic continent through long-range atmospheric transport (LRAT). In these areas, low temperatures play a significant role in the environmental fate of POPs, retaining them for a long time due to cold trapping by diffusion and wet deposition, acting as a net sink for many POPs. However, in the current context of climate change, the remobilization of POPs that were trapped in water, ice, and soil for decades is happening. Therefore, continuous monitoring of POPs in polar air is necessary to assess whether there is a recent re-release of historical pollutants back to the environment. We reviewed the scientific literature on atmospheric levels of several POP families (polychlorinated biphenyls - PCBs, hexachlorobenzene - HCB, hexachlorocyclohexanes - HCHs, and dichlorodiphenyltrichloroethane - DDT) from 1980 to 2021. We estimated the atmospheric half-life using characteristic decreasing times (TD). We observed that HCB levels in the Antarctic atmosphere were higher than the other target organochlorine pesticides (OCPs), but HCB also displayed higher fluctuations and did not show a significant decrease over time. Conversely, the atmospheric levels of HCHs, some DDTs, and PCBs have decreased significantly. The estimated atmospheric half-lives for POPs decreased in the following order: 4,4' DDE (13.5 years) > 4,4' DDD (12.8 years) > 4,4' DDT (7.4 years) > 2,4' DDE (6.4 years) > 2,4' DDT (6.3 years) > α-HCH (6 years) > HCB (6 years) > 3-HCH (4.2 years). For PCB congeners, they decreased in the following order: PCB 153 (7.6 years) > PCB 138 (6.5 years) > PCB 101 (4.7 years) > PCB 180 (4.6 years) > PCB 28 (4 years) > PCB 52 (3.7 years) > PCB 118 (3.6 years). For HCH isomers and PCBs, the Stockholm Convention (SC) ban on POPs did have an impact on decreasing their levels during the last decades. Nevertheless, their ubiquity in the Antarctic atmosphere shows the problematic issues related to highly persistent synthetic chemicals. © 2023 Thais Luarte et al.
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    Occurrence and air-water diffusive exchange legacy persistent organic pollutants in an oligotrophic north Patagonian lake
    (Academic Press Inc., 2022-03) Luarte, Thais; Tucca, Felipe; Nimptsch, Jorge; Woelfl, Stefan; Casas, Gemma; Dachs, Jordi; Chiang, Gustavo; Pozo, Karla; Barra, Ricardo; Galbán-Malagón, Cristóbal
    In this study, the occurrence and diffusive air-water exchange of POPs in Panguipulli Lake (39°42′S-72°13′W), an oligotrophic lake located in northern Patagonia (Chile), were determined. Air and water samples were collected between March and August 2017 (autumn-winter) and analyzed for concentrations of OCPs (α-HCH, β-HCH, γ-HCH and HCB) and PCBs (PCB-28,-52,-101,-118,-153,-158,-180) using gas chromatography coupled with an electron capture detector. The direction of air-water exchange direction was evaluated using a fugacity approach (ƒw ƒa−1), and net diffusive exchange fluxes (FAW, ng m−2 d−1) were also estimated. Total ∑4OCP levels in air ranged from 0.31 to 37 pg m−3, with a maximum for β-HCH, while Σ7PCB levels ranged from 3.05 to 43 pg m−3. The most abundant congener was PCB-153, accounting for 60% of the total PCBs in air. Surface water ∑4OCPs measured in this study ranged from 1.01 to 3.9 pg L−1, with γ-HCH predominating, while surface water Σ7PCB levels ranged from 0.32 to 24 pg L−1, with PCB-101, PCB-118, and PCB-153 presenting the highest levels. Diffusive air-water exchanges of HCB, α-HCH, γ-HCH and PCBs in the form of volatilization from the lake to air predominated; in contrast, for β-HCH net deposition dominated during the sampling period. Estimates suggested faster microbial degradation in the dissolved phase compared to atmospheric degradation for all analyzed POPs. Overall, these results could indicate that the oligotrophic lakes of northern Patagonia act as a secondary source of atmospheric POPs, mainly PCBs and some OCPs. This study is a first attempt to understand the occurrence of POPs in air and water, as well as their dynamics in oligotrophic lakes in the southern hemisphere. © 2021
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    South American National contributions to knowledge of the effects of endocrine disrupting chemicals in wild animals: current and future directions
    (MDPI, 2022-12) Rojas-Hucks, Sylvia; Rodriguez-Jorquera, Ignacio A.; Nimpstch, Jorge; Bahamonde, Paulina; Benavides, Julio A.; Chiang, Gustavo; Pulgar, José; Galbán-Malagón, Cristóbal J.
    Human pressure due to industrial and agricultural development has resulted in a biodi versity crisis. Environmental pollution is one of its drivers, including contamination of wildlife by chemicals emitted into the air, soil, and water. Chemicals released into the environment, even at low concentrations, may pose a negative effect on organisms. These chemicals might modify the synthesis, metabolism, and mode of action of hormones. This can lead to failures in reproduction, growth, and development of organisms potentially impacting their fitness. In this review, we focused on assessing the current knowledge on concentrations and possible effects of endocrine disruptor chemicals (metals, persistent organic pollutants, and others) in studies performed in South America, with findings at reproductive and thyroid levels. Our literature search revealed that most studies have focused on measuring the concentrations of compounds that act as endocrine disruptors in animals at the systemic level. However, few studies have evaluated the effects at a reproductive level, while information at thyroid disorders is scarce. Most studies have been conducted in fish by researchers from Brazil, Argentina, Chile, and Colombia. Comparison of results across studies is difficult due to the lack of standardization of units in the reported data. Future studies should prioritize research on emergent contaminants, evaluate effects on native species and the use of current available methods such as the OMICs. Additionally, there is a primary focus on organisms related to aquatic environments, and those inhabiting terrestrial environments are scarce or nonexistent. Finally, we highlight a lack of funding at a national level in the reviewed topic that may influence the observed low scientific productivity in several countries, which is often negatively associated with their percentage of protected areas.