| 1. |
- Capuano Mascarenhas, Luciana, et al.
(författare)
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Multi-criteria analysis of municipal solid waste treatment technologies to support decision-making in Kisumu, Kenya
- 2021
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Ingår i: Environmental Challenges. - : Elsevier BV. - 2667-0100. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The directive to close the dumpsite in Kisumu, Kenya has made the search for alternative solid waste treatment and disposal technologies urgent. The aim of this research is to support the decision-making process by analyzing multiple socioeconomic and environmental parameters of salient solid waste treatment options. We used multi-criteria analysis to assess and compare anaerobic digestion, sanitary landfill, bioreactor landfill, and incineration. Informed by field observations and interviews, the chosen assessment criteria were economic costs, electricity generation, GHG emissions, land footprint, air pollution, soil and water contamination, and compatibility with recycling efforts. A literature review yielded quantitative and qualitative data that supported the analysis and the ranking of solutions according to performance in each criterion. Our analysis shows that anaerobic digestion is a suitable solution for Kisumu, due to its reduced environmental impacts, production of electricity and fertilizer, suitability to treat the large organic waste stream generated in the city, and compatibility with independent recycling activities. Landfilling represents a cheap solution; however, previous failed initiatives indicate that finding available land close to main waste generators is a challenge. Incineration is costly and requires advanced air quality control equipment and high combustibility of incoming waste, which is not the case for Kisumu, where over 60% of waste stream is organic/wet. Our results and recommendations are targeted for the Kisumu case, but they can be relevant for researchers and policymakers elsewhere, especially in low- and middle-income cities facing similar challenges.
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| 2. |
- Felton, Adam, et al.
(författare)
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Forest biodiversity and ecosystem services from spruce-birch mixtures : The potential importance of tree spatial arrangement
- 2022
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Ingår i: Environmental Challenges. - : Elsevier BV. - 2667-0100. ; 6
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Forskningsöversikt (refereegranskat)abstract
- There is increasing empirical support for the biodiversity and ecosystem service (ES) benefits of mixed-species production forests. However, few studies control for the spatial arrangement of the trees within mixtures to determine the influence that clustering the tree species (patch scale mixtures), versus evenly dispersing them (intimate scale mixtures), may have for biodiversity and ES outcomes. To highlight the potential implications of altering tree spatial arrangement in mixtures, and the need to fill related knowledge gaps, here we provide a qualitative multi-disciplinary overview of ecological and socio-economic drivers with the potential to alter biodiversity, ecosystem services, and management-related outcomes from patch versus intimate scale mixtures. We focused our overview on even-aged mixtures of Norway spruce (Picea abies) and birch (Betula pendula or B. pubescens) in Sweden, which enabled us to contrast findings within a biogeographical and silvicultural setting. Specifically, we targeted implications for biodiversity (understory vascular plants, epiphytic lichens, saproxylic beetles, birds), biomass production, harvesting costs, management ease, recreation and aesthetics, cervid game, as well as abiotic and biotic risks (wind, fire, pathogens, pests, browsing damage). In the absence of direct empirical evidence, we primarily relied on expert inference from theory and relevant empirical studies sourced from the Fennoscandian region, and further afield if needed. Collectively these efforts allowed us to develop a number of informed hypotheses indicating that for spruce-birch mixtures in this region, patch scale mixtures may have the potential to favour the diversity of several forest dependant taxonomic groups, cervid game and reduce harvesting costs, whereas intimate mixtures may have the potential to reduce pathogen and pest damage, and likewise, potentially benefit production outcomes. Current knowledge was too limited, inconsistent or context dependant to even tentatively infer outcomes for fire risk, wind damage, browsing damage, management ease, recreational and aesthetic outcomes. We emphasize that our hypotheses require testing, but are sufficient to (1) highlight the likely importance of spatial-scale to biodiversity and ecosystem services outcomes in mixed-species production forests, (2) caution against generalization from mixture studies that lack scale considerations, and (3) motivate the targeted consideration of spatial grain in future mixture studies.
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| 3. |
- Gemeda, S.T., et al.
(författare)
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Diarrheagenic toxins in stool correlate to drinking water from improved water sources in Ethiopia
- 2022
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Ingår i: Environmental Challenges. - : Elsevier. - 2667-0100. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli toxins are the most common types found in association with disease in E. coli bacteria. They are found in nearly all pathogenic E. coli bacteria either released from the bacteria or E. coli cell or both transmitted via the orofecal route. The present study evaluated the relationship between E. coli toxins detected in ‘improved’ drinking water sources and toxins found in stool samples from individuals with diarrhea that consumed the water. Improved water is defined as the water source, by the nature of their construction or through active intervention, are protected from external contamination, particularly with fecal matter. A correlation between toxins in the water with toxins in the stools suggests that contaminated drinking water is a potential infection source. Stool samples were collected from people with diarrhea (248 stool samples) and their drinking water at their home (248 water samples). Only diarrhea patients that reported use of improved drinking water sources as per the definition of the WHO/UNICEF Joint Monitoring Programme were included in the study. E. coli isolates were analysed for 5 major toxins (enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1), heat-stable enterotoxin a (Sta); shiga-like toxin 1 (Stx1), shiga-like toxin 2 (Stx2), and heat-liable enterotoxin (LT)) using a multiplex polymerase chain reaction (mPCR). Descriptive statistics, Chi-square (χ2) test, Fisher's exact, logistic regression, and bivariate Pearson correlation coefficients were used to examine the association and correlation of toxins in the drinking water with those in the stool samples. Of the 248 households, 24% had positive results in both water and stool samples, 63% [Confidence Interval (CI): 55–67%] had positive results in water samples only and 46% [CI: 37- 49%] were found to be positive for toxins in stool samples only. EAST1 was the most frequently detected from the 5 toxins evaluated, with 33% in the water and 38% in the stool. ESAT1, Stx1, and LT toxins were the most commonly found contaminants in water from improved water sources. The prevalence of toxins in household water samples was higher than that obtained from yard connections (51%) and piped systems connected to public stands (42%), compared to the other types of water sources. Both a positive correlation (P < 0.05; r = 0.412) and statistically significant association (P=0.0001) was found between the toxins in the water and toxins in the stool. EAST1 in the stool was significantly correlated with overall toxins in water (r = 0.378) and increased the probability of the occurrence of EAST1 in water (odds ratio (OR)=4.96, 95% CI, 2.81–8.74; P=0.000). E. coli toxins have been found to be effective biomarkers for detecting possible drinking water contamination in households with diarrhea. Long-term planning for the protection and/or treatment of stored household drinking water to ensure toxins free water at the point of use are required.
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| 4. |
- Islam, M. Shahidul, et al.
(författare)
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Is road-side fishpond water in Bangladesh safe for human use? An assessment using water quality indices
- 2022
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Ingår i: Environmental Challenges. - : Elsevier BV. - 2667-0100. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Pond water is used in everyday life by many people in Bangladesh, however, without sufficient and reliable information regarding water quality and pollution status. For this reason, geospatial analysis and mapping of water quality indices such as metal (MI), contamination (Cd), and physicochemical water quality index (WQI) were assessed to improve the understanding of potential pollution sources. Samples were collected from twenty randomly selected ponds situated in Jashore Sadar Upazila, Bangladesh. Nineteen (19) water quality parameters were measured, including pH, temperature, EC, TDS, total suspended solids (TSS), chloride, alkalinity, total hardness, salinity, Fe, Mn, Pb, Cr, Cd, Co, Zn, Ag, Ni, and Cu. The average concentration of Fe, Mn, Pb, Cd, and Ag was much higher than recommended standards. The WQI ranged from 1.59-5.27, Cd from -0.19-18.28, and MI from 7.81-26.28. The spatial distribution of MI indicates that the south-western and south-eastern region of the study area are stands out with a very high pollution pressure. The spatial distribution of Cd, follows the same trend as for MI. A multitude of different types of pollution sources contributes to the high pollution load such as, municipal wastewater, leachate from landfills, small industry wastewater and stormwater, and agricultural runoff. The studied pond water is highly polluted and not suitable for household use and fish consumption.
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| 5. |
- Lundgren, Maria, et al.
(författare)
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Predictive modeling of plant uptake of Pb and Cd : Implications of aerial deposition and the origin of parameterisation data
- 2023
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Ingår i: Environmental Challenges. - : Elsevier. - 2667-0100. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- We developed ordinary least squares regression models to predict uptake of cadmium and lead, two metals that are of public health significance because of their toxicity, in the edible tissues of lettuce. Models were parameterised using data on soil metal concentration, pH, and organic carbon. To assess the impact of physical contamination in form of aerial deposition and soil-splash on the metal concentration in lettuce, separate linear regression models were parameterised for indoor- and outdoor-grown lettuce, assuming the physical contamination to be negligible for indoor conditions. Both Cd models showed high model fit and strong predictive performance, when tested on an independent dataset, suggesting uptake via roots to be dominant. For Pb, the indoor model performed better than the outdoor model, indicating that physical contamination, contributes significantly to metal concentration in lettuce leaves. Our results highlight the importance of the parameterisation data when developing uptake models for predictions and risk assessment. Regression models for predicting Pb concentration in lettuce based on indoor data should not be used for predicting lettuce concentrations cultivated in outdoor conditions unless the contribution of physical contamination is explicitly accounted for.
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| 6. |
- Rawat, Monika, et al.
(författare)
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Visitors off the trail : Impacts on the dominant plant, bryophyte and lichen species in alpine heath vegetation in sub-arctic Sweden
- 2021
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Ingår i: Environmental Challenges. - Amsterdam : Elsevier. - 2667-0100. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Alpine ecosystems are under increasing pressure due to tourism and recreational activities. When leaving desig- nated trails as is frequently observed, visitors can cause unintentional damage to vegetation. This study investi- gated the effect of human trampling on the dominant species of vascular plants, bryophytes and lichens along an infrequently used hiking trail in an alpine ecosystem in sub-arctic Sweden. The hypothesis tested was that prox- imity to the trail (as an effect of more people leaving the trail for a short distance compared to a longer distance) causes a decrease in species with low resistance to trampling. With a greater decrease in taller forbs and shrubs than in graminoids and prostrate plants, a greater decrease in lichen than in bryophyte species, and a change in vegetation composition. The results showed that proximity to the trail did not cause a decrease in the majority of dominant species, with none of the eight most dominant vascular plants showing any significant effects of prox- imity to the trail. One bryophyte species (Dicranum elongatum) among the six most commonly found decreased with proximity to the trail. Three lichen species (Cladonia arbuscula, Cladonia uncinalis, Ochrolechia frigida) among the eight most common species decreased with proximity to the trail. There was no evidence that taller species decreased with proximity to the trail, although the deciduous shrub Betula nana showed a tendency for a decrease. Proximity to the trail caused a greater decrease in lichen species than in bryophyte species. Multivariate analyses showed that distance from trail and transect direction had significant effects on overall vegetation composition. The level of low-intensity trampling recorded indicates that current numbers of hikers at the site can be sustained for longer periods with minimum impact on vascular plant species, but to get a more general understanding of the impact of low-intensity trampling data from additional sites are needed. © 2021 The Author(s)
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| 7. |
- WM-Bekele, Daniel, et al.
(författare)
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Pharmaceutical pollution in an Ethiopian rift valley lake Hawassa : occurrences and possible ecological risks
- 2024
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Ingår i: Environmental Challenges. - : Elsevier. - 2667-0100. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Most information on the occurrences of active pharmaceutical ingredients (APIs) in natural water bodies comes from developed nations, leaving developing countries like Ethiopia understudied. This study examines the presence and potential ecological risks of APIs in Lake Hawassa, a tropical freshwater lake in the Ethiopian Rift Valley. The study analyzed 36 APIs from 11 therapeutic classes of human medications in water and sediment samples. The risk quotient (RQ) method was used to assess ecological risks to aquatic organisms. Forty-five composite samples of water and sediment were collected from five sites during three sampling events. The samples were analyzed in the Chemistry laboratory at the University of Umeå, Sweden using the ultrahigh-performance liquid chromatography mass spectrometer (UHPLC-MS/MS) method. The results indicated that 16 APIs were detected in the water samples and three in the sediment. Ciprofloxacin, artesunate, mefloquine, fluconazole, and tramadol were the most frequent APIs detected in the analyzed water samples. The concentration of ciprofloxacin was the highest of all the APIs, detected with RQ > 1, indicating high risk to the aquatic biota in the Lake Hawassa ecosystem. Similarly, diclofenac, and sulfonamide in water, lorazepam, mefloquine, and lumefantrine in sediments, occurred at concentrations that could cause a medium risk (RQ > 0.1) to the aquatic biota. The occurrence of the APIs in the Lake Hawassa ecosystem affirms early warning, and the Antibiotics may create Antibiotic-resistant genes posing a public health threat. Therefore, it is crucial to implement systems for gathering unused medications and monitoring waste disposal and sewage treatment in the study area. Despite the limited research on APIs in the region where this study was conducted, our findings are highly valuable for understanding APIs in freshwater ecosystems worldwide. Our results align with global concerns about APIs, making them a valuable tool for creating universally applicable guidelines.
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