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The rapid increase in waste generation in developing countries presents significant challenges, necessitating effective waste management strategies. This study examines the influence of individual, household and institutional factors on waste sorting behaviours in Ecuador, employing an ordered logistic regression model. Data were sourced from the 2019 National Multipurpose Household Survey (NMHS) and the Census of Economic Environmental Information in Decentralised Autonomous Governments (CEEIGAD). The NMHS uses a two-stage probabilistic sampling methodology, with census sectors as the primary sampling units and households as the secondary units. After excluding outliers and selecting individuals aged 15-65 years, the final sample consisted of 8601 households, including 26,175 individuals. The findings reveal that personal attributes such as gender, ethnicity, age, marital status and environmental concern significantly influence waste sorting behaviours. Household characteristics, including urban or rural location, are also critical. Institutional factors, such as municipal regulations, waste collection fees and waste separation at source, play essential roles in promoting waste separation. The study highlights the necessity for targeted governmental policies. Recommendations include improving environmental education, increasing sorting infrastructure in urban areas and ensuring waste collection systems maintain the separation of waste streams.
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Proper household organic waste management practices are crucial to limit the negative environmental and health impacts that can result from inappropriate municipal waste treatment. The environmental impacts of organic waste have previously been described in the literature, and the main treatment strategy for managing such waste relies on technical facilities such as biodigesters. However, such technologies require significant financial investments, which could hinder their application in areas with lower economic power. Among the several available organic waste treatment strategies, composting for urban agricultural (UA) use has become increasingly popular. Although the literature suggests that UA can contribute to organic waste management by encouraging self-treatment practices, investigations into how practising UA can influence household waste management behaviours have been limited thus far. To this end, we analyse the role of practising UA along with other demographic variables, such as age, gender, education, income and housing conditions, in influencing citizens' household organic waste management behaviours. The city of Florianópolis, Brazil was selected as a case study since that municipality recently passed a new organic waste regulation law that supports the use of organic compost in UA. We surveyed 206 individuals regarding their household organic waste management habits in four behavioural areas: (i) separation, (ii) use of public services, (iii) self-treatment and (iv) reduction. The dataset comprises 102 individuals who were actively engaged in UA activities and 104 who were not involved in UA to compare habits of the two groups. The results show that UA practitioners are more likely to separate and self-treat their organic waste and use the derived compost for gardening activities. The use of public facilities for organic waste management is influenced by people's housing conditions. Respondents who lived in an apartment with no access to a garden logically had a lower willingness than did those with garden access to self-treat the organic waste produced. On the other hand, the results show that UA practitioners compost their own organic waste regardless of their housing conditions. The results show a strong, positive influence of practising UA on self-composting and thereby highlight the role of such practices in sensitizing urban residents to waste management issues and supporting local organic waste management strategies. Although the debate over the role of UA in organic waste management is still open, we reveal that highlighting this role could support a shift towards a circular approach to organic waste treatment.
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The pressing challenges in waste management have motivated this comprehensive study examining prior research and contemporary trends concerning innovation and waste management. A meticulous investigation of 2264 documents (1968-2024) was conducted using bibliometrix R-tool to analyse Scopus and Web of Science databases, offering a holistic global perspective. Heightened societal concern about waste management, driven by soaring waste production from consumption patterns, requires urgent exploration of effective waste elimination and transformation systems. This study provides a comprehensive summary of the topic, delving deeply into its complexities. Through thorough analysis of global trends, it constitutes a significant stride towards identifying effective solutions, offering valuable contributions to both scientific understanding and practical applications. This research pioneers a comprehensive synthesis of innovation and waste management issues, showcasing originality and substantial contributions. The identified collaborative networks expose a lack of transnational cooperation, potentially hindering waste management innovation. Future research around waste management innovation should focus on synergies among competitors within the same industry and across industries to minimize waste and maximize resource utilization, 4.0 technologies, global waste chain impacts and challenges along with solutions for developing countries.
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Healthcare waste management is a critical aspect of public health and environmental protection, particularly in establishments such as dental clinics. This study examined the dental clinic waste (DCW) management processes in clinics within the city of Belo Horizonte, Brazil. Utilizing data from Healthcare Waste Management Plans (HCWMP) provided by the Urban Cleaning Superintendence, the study investigated waste generation, segregation, storage, collection, treatment, and final disposal practices. The results revealed that hazardous DCW represented a significant portion (26.5 %) of waste generated in dental clinics, exceeding the World Health Organization's recommended threshold. Biological waste (22.9 %), mainly consisting of cotton, gauze, and gloves contaminated with blood or body fluids, was the most generated hazardous waste group, followed by chemical (2.2 %) and sharps waste (1.3 %). Incineration was the predominant treatment method for hazardous DCW, raising concerns about environmental impacts and greenhouse gas emissions. Non-hazardous waste, primarily destined for landfills, had limited recycling rates (2.4 %), emphasizing the need for improved waste management strategies to minimize environmental impacts and increase circular economy. Challenges in DCW management included inadequate segregation practices, limited recycling initiatives, and incomplete HCWMPs lacking descriptions of waste management beyond establishment boundaries. Addressing these challenges requires comprehensive training programs, strengthened regulations, and increased environmental awareness among healthcare professionals. In conclusion, improving DCW management in dental clinics is crucial for mitigating occupational and environmental risks. Collective efforts are needed to enhance waste segregation, promote recycling, and ensure compliance with regulations, ultimately safeguarding public health and the environment.
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Clínicas Odontológicas , Residuos Peligrosos , Eliminación de Residuos Sanitarios , Brasil , Eliminación de Residuos Sanitarios/métodos , Reciclaje/métodos , Administración de Residuos/métodos , Residuos Dentales/análisis , Incineración , HumanosRESUMEN
This study presents comprehensive insights into the microbiological profile across all concentrated chicken broth processing stages, utilizing a combination of amplicon sequencing based on metataxonomic and culturing techniques. Samples were systematically collected throughout the production chain, with each batch yielding 10 samples per day across eight different dates. These samples underwent thorough analysis, including 16S rRNA and ITS sequencing (n = 30), culture-dependent microbiological tests (n = 40), and physical-chemical characterization (n = 10). Culturing analysis revealed the absence of Listeria monocytogenes and Salmonella spp. at any stage of processing, counts of various microorganisms such as molds, yeasts, Enterobacteria, and others remained below detection limits. Notably, spore counts of selected bacterial groups were observed post-processing, indicating the persistence of certain species, including Bacillus cereus and Clostridium perfringens, albeit in low counts. Furthermore, the study identified a diverse array of bacterial and fungal species throughout the processing chain, with notable occurrence of spore-forming bacteria. The presence of spore-forming bacteria in the final product, despite thermal processing, suggests the need for enhanced strategies to mitigate their introduction and persistence in the processing premises. Thus, this study offers valuable insights into microbial dynamics and diversity through processing concentrated chicken broth.
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Bacterias , Pollos , Microbiología de Alimentos , Hongos , Pollos/microbiología , Hongos/clasificación , Hongos/genética , Hongos/aislamiento & purificación , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/crecimiento & desarrollo , Animales , Manipulación de Alimentos/métodos , ARN Ribosómico 16S/genética , Recuento de Colonia Microbiana , Contaminación de Alimentos/análisis , Medios de Cultivo/químicaRESUMEN
Waste disposal systems are crucial components of environmental management, and focusing on this sector can contribute to the development of various other sectors and improve social welfare. Urban waste is no longer solely an environmental issue; it now plays a significant role in the economy, energy, and value creation, with waste disposal centers (WDCs) being a key manifestation. The purpose of this study is to measure the performance of WDCs in the state of Nuevo León, Mexico, with the aim of developing environmental, social, and governance (ESG) strategies to strengthen and prepare the WDCs for the industrial developments in this state. By identifying environmental variables and undesirable factors, the efficiency and managerial capacity of 32 WDCs were assessed. The analysis revealed that 9 out of the 32 WDCs are technically efficient, while the remaining 23 require significant improvements. Using the Data Envelopment Analysis (DEA) technique, an average efficiency score of 0.91 was found, with a standard deviation of 0.08. The managerial capacity analysis indicated that the highest-ranked WDC achieved an efficiency score of 1, whereas the lowest-ranked WDC scored 0.67. Finally, an operational map of development strategies was developed using the Interpretive Structural Modeling (ISM) and Matrix Impact Cross-Reference Multiplication Applied to a Classification (MICMAC) approach. The results indicate that four phases of development should be followed for real development and maturity of development in these WDCs, including Groundwork, Structuring, Development and Growth, and Smart Maturity.
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Administración de Residuos , México , Administración de Residuos/métodos , Instalaciones de Eliminación de Residuos , Eliminación de Residuos/métodos , Ciudades , Ambiente , Conservación de los Recursos Naturales/métodosRESUMEN
Cheese whey (CW), by-product of cheese production, has potential as a valuable resource due to its nutritional composition. Although options for CW degradation have been explored, a biological treatment with black soldier fly larvae (BSFL) has not been reported. This study evaluated the growth and composition of BSFL in four experimental diets with CW under different conditions. Results show that the use of CW allows larval development and weight gain, also, the conversion into larval biomass was up to 0.215. Diets ED3 (fresh CW, 38 °C) and ED4 (fresh CW, room temperature) allowed higher weight accumulation (final weight up to 0.285 g); the highest fat accumulation (12 % higher than control) was observed in ED3 (up to 45.57 %), which had less protein. Moreover, higher amounts of saturated fatty acids are generated. This study highlights the importance of an appropriate pretreatment designed for a specific waste to control desired by-products.
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Environmental concerns about microplastics (MPs) have motivated research of their sources, occurrence, and fate in aquatic and soil ecosystems. To mitigate the environmental impact of MPs, biodegradable plastics are designed to naturally decompose, thus reducing the amount of environmental plastic contamination. However, the environmental fate of biodegradable plastics and the products of their incomplete biodegradation, especially micro-biodegradable plastics (MBPs), remains largely unexplored. This comprehensive review aims to assess the risks of unintended consequences associated with the introduction of biodegradable plastics into the environment, namely, whether the incomplete mineralization of biodegradable plastics could enhance the risk of MBPs formation and thus, exacerbate the problem of their environmental dispersion, representing a potentially additional environmental hazard due to their presumed ecotoxicity. Initial evidence points towards the potential for incomplete mineralization of biodegradable plastics under both controlled and uncontrolled conditions. Rapid degradation of PLA in thermophilic industrial composting contrasts with the degradation below 50 % of other biodegradables, suggesting MBPs released into the environment through compost. Moreover, degradation rates of <60 % in anaerobic digestion for polymers other than PLA and PHAs suggest a heightened risk of MBPs in digestate, risking their spread into soil and water. This could increase MBPs and adsorbed pollutants' mobilization. The exact behavior and impacts of additive leachates from faster-degrading plastics remain largely unknown. Thus, assessing the environmental fate and impacts of MBPs-laden by-products like compost or digestate is crucial. Moreover, the ecotoxicological consequences of shifting from conventional plastics to biodegradable ones are highly uncertain, as there is insufficient evidence to claim that MBPs have a milder effect on ecosystem health. Indeed, literature shows that the impact may be worse depending on the exposed species, polymer type, and the ecosystem complexity.
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Plásticos Biodegradables , Biodegradación Ambiental , Microplásticos , Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis , Contaminantes del Suelo/análisis , PlásticosRESUMEN
Sustainable agriculture involves adopting best practices in food production to promote environmental and economic sustainability. Its implementation primarily aims to utilise organic residues to increase yield, diversify production, and reduce costs. In this context, the objective of this study was to investigate different substrates for Hypsizygus ulmarius production and, from its residual substrate, to develop formulations for lettuce seedling growth and subsequent greenhouse cultivation. For mushroom production, substrates were prepared from sawdust with the addition of wheat bran, rice bran, soybean meal, and calcite, resulting in four distinct substrate formulations. The spent mushroom substrate (SMS), obtained at the end of cultivation, was used for lettuce seedling production along with the commercial substrate Carolina Soil® and the soil conditioner BacSol®. The top five formulations were selected for transplanting in the greenhouse. Regarding mushroom production, substrates with higher carbon/nitrogen ratios, around 66: 1, resulted in higher yields. For seedling production, SMS showed lower efficiency compared to the commercial substrate Carolina Soil®, which also benefited from the addition of the soil conditioner BacSol®. However, after transplanting lettuce seedlings, the formulation containing SMS showed superior results in almost all evaluated parameters. Therefore, we concluded that despite the inefficiency of using H.ulmarius SMS for lettuce seedling production, it favours the establishment of seedlings in greenhouse cultivation environments.
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Agaricales , Agricultura , Lactuca , Lactuca/crecimiento & desarrollo , Agricultura/métodos , Micelio/crecimiento & desarrollo , Plantones/crecimiento & desarrollo , Desarrollo Sostenible , Suelo/químicaRESUMEN
Costa Rica is at the forefront of environmental conservation in Central America, with its focus on sustainability and green practices. Building on this foundation, the country joins a cohort of middle-income developing countries that have set forth ambitious goals to eliminate plastic pollution and become plastics-free. Recycling remains one of the most effective ways of removing plastic waste from the environment. Although GIS has been utilized in environmental research, its use is still expanding in developing countries of the Global South. These countries are experiencing unprecedented adverse climate and ecological impacts while also pursuing fundamental socioeconomic growth. The application of more cost-effective and strategic technological solutions, as well as data-driven decision-making, could fast-track the achievement of their urgent environmental goals. Using Geographic Information Systems (GIS) analysis, this study applies hot spot, location-allocation, and time-distance measures to examine Costa Rica's capacity to recycle plastic waste. Focusing specifically on availability and the public's access to recycling facilities, this article offers insights into the resource constraints and evolution of plastics governance in developing countries with environmentally-focused priorities. The findings of this study suggest that while Costa Rica is implementing progressive plastics regulatory policies, the ability to achieve plastics-free status is hampered by shortfalls in the number and distribution of recycling facilities and the public's access to recycling services. Expanding recycling infrastructure, including transportation, and adopting a less canton-centric waste administration system could contribute to resolving these challenges. This study contributes to discourses on global plastics governance and environmental change management in the Global South.
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Contaminación Ambiental , Sistemas de Información Geográfica , Plásticos , Reciclaje , Costa Rica , Plásticos/análisis , Contaminación Ambiental/estadística & datos numéricos , Análisis Espacial , Conservación de los Recursos Naturales/métodos , Monitoreo del AmbienteRESUMEN
The transition towards Circular Economy (CE) is a promising approach to sustainable development that may cause significant social impacts. Despite the benefits of CE initiatives, key players such as informal recyclers face serious social issues such as poverty, lack of social security, and discrimination. Although evaluating social impacts remains a considerable challenge, Social Life Cycle Assessment (SLCA) is recognized as a suitable methodology with a life cycle perspective. While most SLCA experiences are conducted in the formal sector, it is important to consider the informal sector, which plays a crucial role in developing countries. This article presents an analysis of SLCA studies in informal recycling settings in order to identify the challenges and adjustments required for informal settings. The analysis is based on a literature review and a documentary review of a pilot application of SLCA in the informal recycling system in Cuenca, Ecuador. The results show that SLCA requires adaptation to be applied in informal settings. There are particular challenges in delineating boundaries due to the fuzzy nature and variability of informal activities. Tasks such as establishing specific indicators, developing reference scales and data collection, require careful planning and active stakeholder participation. For instance, indicators regarding Fair Salary or Working hours were adapted based on best practices. Furthermore, tasks such as verifying and disseminating results should be included in interpretation phases to generate long-term impacts and influence behaviors. The study underscores SLCA's multidimensional view but highlights the need for further standardization and adaptation for informal sectors.
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Reciclaje , Reciclaje/métodos , Humanos , Ecuador , Sector Informal , Administración de Residuos/métodos , Desarrollo SostenibleRESUMEN
This study aimed to explore alternative substrates for growing forest species using eucalyptus bark. It evaluated the potential of extracted Eucalyptus globulus fiber bark as a substitute for commercial growing media such as coconut fiber, moss, peat, and compost pine. We determined the physicochemical parameters of the growing media, the germination rate, and the mean fresh and dry weights of seedlings. We used the Munoo-Liisa Vitality Index (MLVI) test to evaluate the phytotoxicity of the bark alone and when mixed with commercial substrates. Generally, the best mixture for seed growth was 75% extracted eucalyptus bark fiber and 25% commercial substrates. In particular, the 75E-25P (peat) mixture is a promising substitute for seedling growth of Pinus radiata, achieving up to 3-times higher MLVI than the control peat alone. For Quillaja saponaria, the best growth substrate was the 50E-50C (coconut fiber) mixture, which had the most significant MLVI values (127%). We added chitosan and alginate-encapsulated fulvic acid phytostimulants to improve the performance of the substrate mixtures. The fulvic acid, encapsulated or not, significantly improved MLVI values in Q. saponaria species and P. radiata in concentrations between 0.05 and 0.1% w/v. This study suggests that mixtures with higher levels of extracted fiber are suitable for growing forest species, thus promoting the application of circular economy principles in forestry.
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The significant growth of the cruise ship industry has resulted in economic benefits, but there are also waste management-related challenges. The aim of this case study was to contribute to the research of cruise ship waste management at the Port of Rio de Janeiro. A3 methodology, applied for the first time in this context, was used to create questionnaires to assess the stakeholders involved, revealing that institutional bureaucracy has a negative effect on waste management. In addition, secondary data on unloaded waste, obtained from the transport manifests, showed that 56 % contained reliable information. The main wastes were plastics (57 %), glass (17 %), metal (9 %), and others. With respect to destinations, 41 % were sent to landfills, 55 % recycled and 4 % thermally treated. Only 5 % of cruise ship moorings removed waste at the Port of Rio de Janeiro, attributed to factors such as high costs.
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Navíos , Administración de Residuos , Brasil , Reciclaje , PlásticosRESUMEN
The aim of this research is to analyse the performance of the extended producer responsibility model for the management of end-of-life tires (ELTs) in Ecuador that has been implemented since 2013. For this research, we conducted case studies of, and subsequently, a comparative analysis between, the ELT management system in Ecuador with respect to the ELT management models in Colombia and Brazil. Our findings show that although the programme implementation represented a significant advance in Ecuador's waste management system there are important challenges that should be considered in future adaptations of the programme. Among the measures that can be adopted to improve the ELT management system are the consolidation and stimulation of the market for products made from ELT waste; promotion of other productive sectors linked to the creation of new products and sectors that generate complementary products; enhancement of the generation, socialization and access to knowledge of the waste by-products for micro-, small- and medium-sized enterprises; increase the tire consumer fee, known as 'Ecovalor' and improvement of the quality and availability of information and indicators regarding ELT management. In this sense, the experiences of Colombia and Brazil show important lessons for the Ecuadorian case.
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This study estimates the health-related and public expenditure impacts of the solid waste services provided by public consortia in Brazilian Municipalities from the enactment of Public Consortia law (2005) to 2019. To conduct the analysis, we applied the econometric method of staggered difference-in-differences to publicly available datasets at the municipality level. The results show that the operation of solid waste services by public consortia had statistically significant effects in reducing hospitalizations caused by Schistosomiasis, Diarrhea/gastroenteritis (up to 5 years age) and other intestinal diseases. The results also indicate a positive impact on the reduction of environmental expenses in treated municipalities, supporting the idea that a Solid Waste Consortium can serve as a local coordinator and improve health and fiscal indicators simultaneously. The findings provide quantitative evidence that policymakers at the local and regional level can use to better understand the benefits of adhering to public consortia when preparing new investments and operation developments for this sector. This paper contributes to the literature of applied research in solid waste by shedding light on the underexplored theme of the intergovernmental cooperative arrangements, which can be instrumental in accelerating and enhancing the development of solid waste services.
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Rodents are notorious pests, known for transmitting major public health diseases and causing agricultural and economic losses. The lack of site-specific and national standardised rodent surveillance in several disadvantaged communities has rendered interventions targeted towards rodent control as often ineffective. Here, by using the example from a pilot case-study in the Bahamas, we present a unique experience wherein, through multidisciplinary and community engagement, we simultaneously developed a standardised national surveillance protocol, and performed two parallel but integrated activities: (1) eight days of theoretical and practical training of selected participants; and (2) a three-month post-training pilot rodent surveillance in the urban community of Over-the-Hill, Nassau, The Bahamas. To account for social and environmental conditions influencing rodent proliferation in the Bahamas, we engaged selected influential community members through a semi-structured interview and gathered additional site-specific information using a modified Centers for Diseases Control and Prevention (CDC) exterior and interior rodent evaluation form, along with other validated instruments such as tracking plates and snap trapping, to test and establish a standardised site-specific rodent surveillance protocol tailored for the Bahamas. Our engagement with community members highlighted poor disposal of animal and human food, irregular garbage collection, unapproved refuse storage, lack of accessible dumpsters, poor bulk waste management, ownership problems and structural deficiencies as major factors fuelling rodent proliferation in the study areas. Accordingly, results from our pilot survey using active rodent signs (that is, the presence of rodent runs, burrows, faecal material or gnawed material) as a proxy of rodent infestation in a generalized linear model confirmed that the variables earlier identified during the community engagement program as significantly correlated with rodent activities (and capturing) across the study areas. The successful implementation of the novel site-specific protocol by trained participants, along with the correlation of their findings with those recorded during the community engagement program, underscores its suitability and applicability in disadvantaged urban settings. This experience should serve as a reference for promoting a standardised protocol for monitoring rodent activities in many disadvantaged urban settings of the Global South, while also fostering a holistic understanding of rodent proliferation. Through this pilot case-study, we advocate for the feasibility of developing sustainable rodent control interventions that are acceptable to both local communities and public authorities, particularly through the involvement of a multidisciplinary team of professionals and community members.
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Residuos de Alimentos , Administración de Residuos , Animales , Humanos , Salud Pública , Roedores , Poblaciones VulnerablesRESUMEN
Water body contamination by leachate originated from dumpsites is a concern for municipal solid waste (MSW) management. In this context, this study aimed to evaluate antioxidant system alterations and oxidative and genotoxic effects in Danio rerio (zebrafish) exposed to leachate from a closed dumpsite. Groups comprising 50 fish were exposed (96 h) to different leachate concentrations (5, 15, 30, and 50%) to evaluate effects on liver and brain superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities and reduced glutathione (GSH) and metallothionein (MT) concentrations, as well as malondialdehyde (MDA) and protein carbonylation (PTC) levels. Blood genotoxicity was evaluated by the comet assay. The investigated dumpsite leachate pond presented high chloride concentrations (Cl-; 2288.4 ± 69.5 mg L-1) and high electrical conductivity (EC; 8434.0 mS cm-1), indicating the presence of leachate. Concerning Danio rerio exposure, higher SOD (37%), CAT (67%), and GST (39%) activities and higher GSH (57%) concentrations were observed in liver following exposure to 50% leachate, while decreased brain GST (42%) activities and GSH (90%) levels were observed at the same leachate concentration. A significant increase in the olive tail moment (OTM; 280%) indicative of genotoxicity in blood was observed. A principal component analysis indicated that increased enzymatic activities and high levels of both GSH and MT were not sufficient to prevent the accumulation of reactive oxygen species, resulting in PTC and genotoxicity. Therefore, leachate exposure causes sublethal Danio rerio effects, altering the antioxidant system, increasing ROS production, and leading to PTC and genotoxicity. The findings demonstrate the need to further develop sublethal level assessments in zebrafish using leachate from different sources to subsidize risk assessments regarding MSW management.
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Perciformes , Contaminantes Químicos del Agua , Animales , Antioxidantes/metabolismo , Pez Cebra/metabolismo , Estrés Oxidativo , Contaminantes Químicos del Agua/toxicidad , Catalasa/metabolismo , Daño del ADN , Superóxido Dismutasa/metabolismo , Perciformes/metabolismo , ClorurosRESUMEN
Leachate, an effluent produced during solid waste decomposition, interacts directly with soil, mainly in dumpsite areas. Studies on terrestrial animal exposure to leachate are, however, lacking. Plants are the most frequently studied organisms, while animal studies, especially earthworms, are limited. Nevertheless, ecotoxicological assessments involving earthworms are crucial due to their role in soil health and ecosystem maintenance, which are paramount in understanding potential terrestrial ecosystem leachate effects. In this context, this study aimed to evaluate behavioral effects, sublethal cytotoxicity and antioxidant system alterations in Eisenia andrei earthworms chronically exposed to leachate from a closed dumpsite. Cytotoxicity was determined by coelomocyte density, viability and cell typing, while antioxidant system alterations were assessed through superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH) and metallothionein (MT) determinations. Malondialdehyde (MDA) and protein carbonylation (PTC) levels were also determined as oxidative effect markers. Finally, the Biomarker Response Index (BRI) was assessed, aiming to quantitatively integrate the results of the investigated endpoints and establish a biological health state (BHS) for each leachate concentration. Leachate exposure led to leak responses at concentrations of up to 50%, but attraction at higher concentrations. Decreased cell density (28%) was observed after 48 days and reduced viability (50%), after 14 days of leachate exposure. The observed cell typing changes indicate anti-inflammatory immune system effects. Leachate exposure led to several antioxidant system alterations, increasing SOD (2-6 %), CAT (5-35 %) and GST (5-70 %) activities and GSH (7-37%) and MT (3-67%) levels. Earthworm antioxidant defenses were, however, able to prevent lipid peroxidation, which decreased (11-37%) following leachate exposure to concentrations above 12.5%, and PTC, which increased at 42 days (26%) and reduced at 56 days (12 %). This is the first PTC assessment in leachate-exposed earthworms. The increased carbonylation levels observed after 42 days alongside MDA decreases highlight the need for further research employing oxidative effect biomarkers other than MDA. Finally, an integrated approach employing the BRI was carried out, revealing mild initial changes evolving to moderate to major effects at the highest leachate exposure concentration, with an effect attenuation detected at the end of the experiment. In this sense, this study brings forth a significant novelty, employing a biomarker previously not assessed in earthworms, demonstrating an oxidative effect, alongside the use of the BRI as an integrative tool for the endpoints applied in this assessment.
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Oligoquetos , Contaminantes del Suelo , Animales , Antioxidantes/metabolismo , Oligoquetos/metabolismo , Estrés Oxidativo , Ecosistema , Contaminantes del Suelo/toxicidad , Contaminantes del Suelo/metabolismo , Superóxido Dismutasa/metabolismo , Suelo , Biomarcadores/metabolismoRESUMEN
Gibberellic acid (GA3) is a natural hormone present in some plants used in agricultural formulations as a growth regulator. Currently, its production on an industrial scale is performed by submerged fermentation using the fungus Gibberella fujikuroi, which is associated with low yields, leaving the purification stages with high costs. An alternative is solid-state fermentation (SSF), which makes it possible to obtain higher concentrations of product using low-cost substrates, such as agroindustrial by-products. This research investigated the use of raw rice bran (RRB) and barley malt residue (BMR) as substrates for GA3 production by the fungus Gibberella fujikuroi. Through two statistical designs, the effect of moisture (50 to 70 wt.%) and medium composition (RRB content between 30 and 70 wt.% to a mass ratio between RRB and BMR) was first evaluated. Using the best conditions previously obtained, the effect of adding glucose (carbon source, between 0 and 80 g·L-1) and ammonium nitrate-NH4NO3-(nitrogen source, between 0 and 5 g·L-1) on GA3 productivity was analyzed. The best yield was obtained using 30 wt.% RRB and 70 wt.% BMR for a medium with 70 wt.% of moisture after 7 days of process. It was also found that higher concentrations of NH4NO3 favor the GA3 formation for intermediate values of glucose content (40 g·L-1). Finally, a kinetic investigation showed an increasing behavior in the GA3 production (10.1 g·kg of substrate-1 was obtained), with a peak on the seventh day and subsequent tendency to stabilization.