خيارات البحث
النتائج 3341 - 3350 من 8,010
Differential physiological responses of a biogenic silver nanoparticle and its production matrix silver nitrate in Sorghum bicolor النص الكامل
2021
Ziotti, Ana Beatriz Sicchieri | Ottoni, Cristiane Angélica | Correa, Cláudia Neves | de Almeida, Odair José Garcia | de Souza, Ana Olivia | Neto, Milton Costa Lima
Silver nanoparticles (AgNP) have been extensively applied in different industrial areas, mainly due to their antibiotic properties. One of the environmental concerns with AgNP is its incorrect disposal, which might lead to severe environmental pollution. The interplay between AgNP and plants is receiving increasing attention. However, little is known regarding the phytotoxic effects of biogenic AgNP on terrestrial plants. This study aimed to compare the effects of a biogenic AgNP and AgNO₃ in Sorghum bicolor seedlings. Seeds were germinated in increasing concentrations of a biogenic AgNP and AgNO₃ (0, 10, 100, 500, and 1000 μM) in a growth chamber with controlled conditions. The establishment and development of the seedlings were evaluated for 15 days. Physiological and morpho-anatomical indicators of stress, enzymatic, and non-enzymatic antioxidants and photosynthetic yields were assessed. The results showed that both AgNP and AgNO₃ disturbed germination and the establishment of sorghum seedlings. AgNO₃ released more free Ag⁺ spontaneously compared to AgNP, promoting increased Ag⁺ toxicity. Furthermore, plants exposed to AgNP triggered more efficient protective mechanisms compared with plants exposed to AgNO₃. Also, the topology and connectivity of the correlation-based networks were more impacted by the exposure of AgNO₃ than AgNP. In conclusion, it is plausible to say that the biogenic AgNP is less toxic to sorghum than its matrix AgNO₃.
اظهر المزيد [+] اقل [-]A review of combined sewer overflows as a source of wastewater-derived emerging contaminants in the environment and their management النص الكامل
2021
Petrie, Bruce
Emerging contaminants such as pharmaceuticals, illicit drugs and personal care products can be released to the environment in untreated wastewater/stormwater mixtures following storm events. The frequency and intensity of combined sewer overflows (CSOs) has increased in some areas due to increasing urbanisation and climate change. Therefore, this review provides an up-to-date overview on CSOs as an environmental source of emerging contaminants. Other than compounds with high removal, those chiral species subject to enantioselective changes (i.e. degradation or inversion) during wastewater treatment can be effective markers of CSO discharge in the environment. A proposed framework for the selection of emerging contaminants as markers of CSOs is outlined. Studies have demonstrated that CSOs can be the main source of emerging contaminants with high removal efficiency during wastewater treatment (e.g. > 90%). However, the impact of CSOs on the environment is location specific and requires decision-making on their appropriate management at catchment level. This process would be aided by further studies on CSOs which incorporate the monitoring of emerging contaminants and their effects in the environment with those more routinely monitored pollutants (e.g. pathogens and priority substances). Mitigation and treatment strategies for emerging contaminants in CSOs are also discussed.
اظهر المزيد [+] اقل [-]Ecological perspectives on water, food, and health security linkages: the Minamata case in Japan النص الكامل
2021
Sarker, Ashutosh
Extant studies address water, food, and health security issues considerably separately and within narrow disciplinary confines. This study investigates the links among these three issues from an ecological viewpoint with a multidisciplinary approach in a modified Millennium Ecosystem Assessment framework developed by the United Nations. The modified framework includes water, food, and health security considerations as the three constituents of human well-being from an ecological (more specifically, ecosystem services) viewpoint. This study examines the links through published data associated with the Minamata incident, which was a historic and horrific methylmercury-induced water, food, and health poisoning crisis in Japan. The results show that when heavy metal pollution changes one component (marine water) of the provisioning ecosystem services, this change subsequently affects another component (seafood) of the services. This then defines the linkages among water, food, and health security as the three constituents of human well-being within the modified framework. The links can have immediate and far-reaching economic, social, legal, ethical, and justice implications within and across generations. This study provides important evidence for emerging economies that ignore the water–food–health security nexus.
اظهر المزيد [+] اقل [-]Rice straw burning: a review on its global prevalence and the sustainable alternatives for its effective mitigation النص الكامل
2021
Singh, Gurraj | Gupta, Munish Kumar | Chaurasiya, Santan | Sharma, Vishal S. | Pimenov, Danil Yu
Being one of the most important staple crops of the world, rice has played a vital role in slaking the calorie requirements of the masses in all the inhabitable continents of our planet. Regardless of this fact, there are many environmental concerns related to the rice production systems across the globe. One of the major worries is the emission of lethal greenhouse gases as a result of the different steps and procedures concerned with rice production and their contribution towards global warming. This study presents the status quo of the rice straw burning practice across the globe. It focuses on the greenhouse gas emissions as a result of the open field burning of rice residues and its direct effect on the environment, eventually contributing towards climate change. The study evidently shortlists the most profound regions contributing towards the open burning dilemma and the socio-political reasons associated with it. The study additionally discusses the different alternatives to straw burning with a clear-cut motive of throwing light on the opportunities that lie in the efficacious and sustainable utilization of homogeneous agricultural wastes. Different in-field straw management techniques related to the farmers and off-field methods related to the industry have been discussed. Predicated upon a survey of the life cycle assessment (LCA) studies across the globe, it is concluded that soil incorporation and electricity generation are the most environment friendly alternatives with an enormous scope of improvement in the coming future.
اظهر المزيد [+] اقل [-]Effectiveness of helminth egg reduction by solar drying and liming of sewage sludge النص الكامل
2021
An-nori, Amal | El Fels, Loubna | Ezzariai, Amine | El Hayani, Bouchra | El Mejahed, Khalil | El Gharous, Mohamed | Hafidi, Mohamed
The present study is aimed at assessing the effectiveness of solar drying process in terms of helminth egg reduction in sewage sludge (SS) generated from an activated sludge wastewater treatment plant (WWTP) in Marrakesh city (Morocco). It is also engaged to highlight a synergic effect of liming (1% CaO) and solar drying on helminth egg reduction. The solar drying process was conducted for 45 days, in summer under a semi-arid climate in a pilot scale polycarbonate-based tunnel (2 m³). Before undergoing solar drying process, data showed an important load of helminth eggs including Ascaris sp., Schistosoma spp., Capillaria spp., Trichuris spp., Ankylostome spp., Toxocara spp., and Taenia spp. in limed sludge (LS) and non-limed sludge (NLS) (15.2 and 17.9 eggs/g, respectively). Ascaris eggs were the most abundant (11.2 and 13.5 eggs/g in LS and NLS, respectively). By the end of the solar drying process, a considerable removal of the total helminth eggs was recorded in LS and NLS (92.8% and 91.6%, respectively). A complete removal of Schistosoma spp., Capillaria spp., Trichuris spp., Toxocara spp. and Taenia spp. was noted in LS and NLS. In the case of Ankylostome spp., data showed a total removal in LS and 81% in NLS; however, the final load is in agreement with the standards (0.4 egg/g). As for Ascaris spp., neither liming nor solar drying process allowed a complete removal (91% and 90% in NLS and LS, respectively) and the final load (1.1 egg/g) does not fulfill the WHO requirements for an agricultural use. Principal component analysis (PCA) demonstrated a negative correlation between dry matter (DM) content (hence temperature) and helminth egg concentration. No significant synergic effect of liming and solar drying process was showed by statistical analysis. This is substantiating that temperature is the key parameter involved in helminth egg removal while undergoing solar drying of SS.
اظهر المزيد [+] اقل [-]To Eat or Not to Eat: the Importance of Starvation on Behavioral Bioassays النص الكامل
2021
Alonso, Alvaro
Behavioral endpoints are important parameters to assess the effects of toxicants and other stressors on natural ecosystems. The relevance of these parameters has caused a rise in their use in aquatic ecotoxicology. However, abiotic and biotic parameters may interact causing changes in the behavioral responses. Among those parameters, starvation of animals is a factor that is usually applied in ecotoxicological short-term bioassays. This could alter animal behavior, along with the toxicant. Therefore, the study of the effects of starvation on baseline behaviors of invertebrates is a relevant issue. This study assessed the behavior of the aquatic snail Potamopyrgus antipodarum under a combination of four treatments: (1) animals normally fed (control treatment), (2) starved animals, (3) animals normally fed and exposed to a high conductivity, and (4) starved animals exposed to a high conductivity. The behavior activity of snails was monitored for 14 days. Results show that animals of the second treatment (starved animals) increased their activity. On the contrary, animals of the third and fourth treatments reduced their activity. Animals from the control treatment showed an activity in between starved animals and animals exposed to high conductivity (both starved and normally fed). These results show that starvation increases the snail activity, but under another environmental stressor (i.e., high conductivity), this trend was reversed. The influence of starvation on behavior should be taken into account in the development of behavioral bioassays.
اظهر المزيد [+] اقل [-]Halogen content relative to the chemical and biochemical composition of fifteen marine macro and micro algae: nutritional value, energy supply, antioxidant potency, and health risk assessment النص الكامل
2021
El Zokm, Gehan M. | Ismail, Mona M. | El-Said, Ghada F.
Marine algae have made a strong contribution to global food security in the future. This study is the first report describing the concentration, pathways, and interactions of halogens in 15 species of marine algae collected from the Eastern Harbor in Alexandria, Egypt, relative to 22 key variables. The relationship between halogen content and chemical and biochemical parameters was studied through multivariate analysis. Among all the tested algae, the iodine content was the lowest (2.53–3.00 μg/g). The range of fluoride and chloride in macroalgae (1.12–1.70 and 0.10–0.46 mg/g) was smaller than that of microalgae (0.10–0.46 and 1.48–3.17 mg/g). The bromide content in macroalgae (0.36–5.45 mg/g) was higher than that in microalgae (0.40–0.76 mg/g). The halogen content in macroalgae was arranged in the order of Br > F > Cl > I. In addition, the biochemical parameters such as carbohydrates, proteins, lipids, and certain heavy metals (Fe, Zn, Cu, Mn, Pb, Ni, Co, Cd, and Cr) were determined. Calories, energy, total antioxidant activity (TAC), K/Na, and ion quotient amounts were estimated. The results showed that the green seaweed species had the highest TAC content. In most of the studied algal species, the calculated ion quotient referred to their likelihood of overcoming high blood pressure. The estimated daily intake (EDI) of algae showed no adverse effects on human health. Most of the research variables are below the acceptable WHO/FAO level. Generally, the calorie content of the selected algae is less than 2 kcal, which makes the algae considered an alternative source of healthy food to reduce obesity.Graphical abstract
اظهر المزيد [+] اقل [-]Cholinesterase characterization and effects of the environmental contaminants chlorpyrifos and carbofuran on two species of marine crabs, Carcinus maenas and Pachygrapsus marmoratus النص الكامل
2021
Nogueira, Ana Filipa | Nunes, Bruno
Cholinesterase characterization and effects of the environmental contaminants chlorpyrifos and carbofuran on two species of marine crabs, Carcinus maenas and Pachygrapsus marmoratus النص الكامل
2021
Nogueira, Ana Filipa | Nunes, Bruno
Among the most frequent targets for toxic effects of modern pesticides, namely organophosphates and carbamates, one may find cholinesterases (ChEs). ChEs exist in a wide variety of animals and have been used actively to discriminate among the environmental effects of different pollutant groups, including the aforementioned pesticides. This study had three purposes, namely (i) identifying the ChE forms present in tissues (eyes and walking legs muscle) of two crab species, Carcinus maenas and Pachygrapsus marmoratus; to (ii) determine the in vitro toxicological effects, and (iii) compare the sensitivity of such enzymatic forms towards commonly used anti-ChE pesticides, namely the organophosphate chlorpyrifos and the carbamate carbofuran. Our results showed that there was not a clear preference for any of the tested substrates in any of the tissues from both species. Furthermore, the ChE activity was almost completely suppressed following incubation with eserine and with the specific inhibitor BW284C51 in all tissues from both species. In vitro exposure to chlorpyrifos promoted a significant decrease in ChE activity in both species. Furthermore, the ChE activity was completely suppressed following incubation with carbofuran and chlorpyrifos. These results suggest that the major ChE forms present in tissues of both crab species show intermediate structural properties and activity patterns, halfway between classic acetylcholinesterase and pseudocholinesterases. However, the sensitivity of the found forms towards ChE inhibitors was established, and the responsiveness of such forms towards common anti-ChE chemicals was established. Both tested species seem to be promising test organisms to be used in marine and coastal scenarios of putative contaminations by anti-ChE chemicals, considering the here reported patterns of response.
اظهر المزيد [+] اقل [-]Cholinesterase characterization and effects of the environmental contaminants chlorpyrifos and carbofuran on two species of marine crabs, Carcinus maenas and Pachygrapsus marmoratus النص الكامل
2021
Nogueira, Ana Filipa | Nunes, Bruno
Among the most frequent targets for toxic effects of modern pesticides, namely organophosphates and carbamates, one may find cholinesterases (ChEs). ChEs exist in a wide variety of animals and have been used actively to discriminate among the environmental effects of different pollutant groups, including the aforementioned pesticides. This study had three purposes, namely (i) identifying the ChE forms present in tissues (eyes and walking legs muscle) of two crab species, Carcinus maenas and Pachygrapsus marmoratus; to (ii) determine the in vitro toxicological effects, and (iii) compare the sensitivity of such enzymatic forms towards commonly used anti-ChE pesticides, namely the organophosphate chlorpyrifos and the carbamate carbofuran. Our results showed that there was not a clear preference for any of the tested substrates in any of the tissues from both species. Furthermore, the ChE activity was almost completely suppressed following incubation with eserine and with the specific inhibitor BW284C51 in all tissues from both species. In vitro exposure to chlorpyrifos promoted a significant decrease in ChE activity in both species. Furthermore, the ChE activity was completely suppressed following incubation with carbofuran and chlorpyrifos. These results suggest that the major ChE forms present in tissues of both crab species show intermediate structural properties and activity patterns, halfway between classic acetylcholinesterase and pseudocholinesterases. However, the sensitivity of the found forms towards ChE inhibitors was established, and the responsiveness of such forms towards common anti-ChE chemicals was established. Both tested species seem to be promising test organisms to be used in marine and coastal scenarios of putative contaminations by anti-ChE chemicals, considering the here reported patterns of response. | published
اظهر المزيد [+] اقل [-]A comparison analysis of the decoupling carbon emissions from economic growth in three industries of Heilongjiang province in China النص الكامل
2021
Liu, Xin | Li, Shunlong
Growing environmental pressure urges China to develop in a sustainable and low carbon way, and thus China strives to achieve a carbon peak by 2030 and carbon neutrality by 2060. As the main energy and heavy industry based in China, carbon emissions in Heilongjiang Provice play a crucial role in achieving China’s climate change targets. Compared with countries with similar populations, Heilongjiang Province (HLJP)’s carbon emissions are still at a low level. In the research on Heilongjiang Province’s carbon emissions among three industries, we apply Tapio decoupling and the Logarithmic Mean Divisia Index (LMDI) method to analyze the decoupling elasticity and effort index of three industries’ growth and carbon emissions in HLJP from 2005 to 2017. Moreover, Deng’s grey relation model is adopted to judge the relation degree between industries and carbon emissions. The results show that: (1) with respect to decoupling, the secondary industry is in a relatively stable state of decoupling; however, the decoupling state of the primary industry is not stable at all, which appears expansive or negative in the studies over the past years. (2) The carbon emissions of three industries show an upward trend during the study period, of which the economic scale effect contributes most, while the energy intensity was the main inhibitor to carbon emissions. (3) Three industrial-economic structures are related to carbon emissions at a high level. The tertiary industry ranks the first, which is followed by the secondary industry and then the primary industry. The economic growth of the tertiary industry is much faster than the other two, hence, its relation degree is the highest. Overall, our analysis can provide an effective reference for the decline of carbon emissions in each industry.
اظهر المزيد [+] اقل [-]Ecological status assessment and non-indigenous species in industrial and fishing harbours of the Gulf of Gabès (central Mediterranean Sea) النص الكامل
2021
Mosbahi, Nawfel | Pezy, Jean-Philippe | Neifar, Lassad | Dauvin, Jean-Claude
Port Biological Baseline Surveys (PBBS) are standardized surveys of the indigenous and non-indigenous marine biodiversity within harbour activities. They provide a baseline for monitoring changes in the structure and function of harbour communities. This study conducted in 12 fishing and industrial harbours from January to December 2018 was the first initiative of a Port Baseline Survey aimed to assess the impact of biological invasions in harbours of the Gulf of Gabès (GG), Tunisia. A total of 174 macrobenthos species were recorded, belonging to eight phyla, with a dominance of crustaceans (32%), molluscs (31%) and polychaetes (20%). Among these species, 57 were non-indigenous species (NIS) for Tunisian waters, while 27 species were recorded for the first time in GG harbours, and three decapods (Dyspanopeus sayi, Hippolyte prideauxiana and Pilumnus minutus) and one amphipod (Hamimaera hamigera) were newly recorded from Tunisian waters. Two main categories of harbours are distinguished according to their macrobenthic communities and environmental conditions. The industrial harbours yield higher richness and abundance of NIS than the fishing harbours. The ALEX metric is used to evaluate the biological invasion status of the Gulf of Gabès harbours and shows that their status ranges from unaffected in fishing harbours to extremely affected in industrial harbours. Three biotic indices (AMBI, BO2A and BENTIX) are applied to assess the ecological status of harbours, which varies from moderate to good. ALEX and the other biotic indices are significantly correlated with harbour characteristics, maritime traffic and edaphic factors (organic matter and chemical contamination). The present study provides a data baseline for the implementation of environmental policies and management plans in the future.
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