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Toxic Effect of Antibiotics on Freshwater Algal Systems and the Mechanisms of Toxicity: A Review Texte intégral
2021
Barsha Roy and P. K. Suresh
Antibiotics are used to treat bacterial infections in humans and animals and also act as a growth promoter for poultry. Due to incomplete metabolism, these antibiotics are excreted in the environment in their parental forms and accumulates in the aquatic ecosystem. Besides the evolution of antibiotic-resistant bacteria, these drugs can damage non-target organisms. Green algae are highly sensitive to different antibiotics. Damage in the algal population will cause imbalances in the ecosystems. Till now, the mechanisms of antibiotic toxicity towards algae have not been completely elucidated. It was observed that antibiotics mainly affected the photosynthetic machinery and decreased the carbon fixation process, finally resulting in algal growth inhibition. This present review deals with antibiotics classification, various routes of antibiotics exposure to the freshwater environment, sensitivity towards the different classes of antibiotics, possible Mode-of-Action (MOA) on algal systems, and gaps that need to be filled. Significant gaps include the unavailability of proper eco-toxicological data for antibiotics. Moreover, they exist in nature as complex mixtures, and their behavior in the ecosystem may vastly differ from the parent molecules. To improve our understanding of antibiotic responses mechanism in real-life scenarios, mixture toxicity studies may be the first step.
Afficher plus [+] Moins [-]Temporal and Spatial Distribution of Zooplankton Inhabiting Sandy and Muddy Shore Habitats at Jazan Coastal Area Texte intégral
2021
A.T. AbdAllah, A.M. Alhababy, M.G. Shamsy, M.S. AbdelDayem and Sahar H. Haroun
Few studies were made about zooplankton distribution in Jazan coastal area. The present study dealt with the identification of zooplankton at the sandy shore (AlSalwa coast) and mangrove muddy shore (Turfa peninsula) at the Almarjan coast. Species richness and population density at different seasons were determined for both study areas between May 2016-April 2017. Conductivity, pH, water temperature, and salinity were measured. The relationship between water characters and the seasonal abundance of zooplankton seasons was examined through regression analysis. Ciliates, Rotifers, Nauplius larva, Gammarus sp., Veliger larva, Nematodes, Planaria, Copepods, and Kinorhyncha were recorded for both study areas. The highest species richness and population density were recorded during the summer season for Almarjan sandy shore and Turfa peninsula mangrove. Ciliates were the most abundant zooplankton on the sandy shore, while Kinorhyncha was the least abundant. The zooplankton Nematode was the most abundant at the Turfa Peninsula mangrove, whereas Gnathostomulida was the least abundant. Conductivity, salinity, and water temperature showed a significant regression relationship (P<0.05) with zooplankton abundance. Data was discussed to highlight the role of zooplankton abundance in the mangrove and sandy shore ecosystem.
Afficher plus [+] Moins [-]Comparative Toxicity Study of Chemical Pesticide and Biopesticide by Daphnia Bioassay Texte intégral
2021
Amrita I. Kakka, Mihir D. Herlekar and Shivani Awale
A comparative study was conducted to evaluate the toxicity of a biopesticide and a chemical pesticide using Daphnia magna as a model aquatic faunal species. The primary survey revealed that Neemark and Tafgor are being commonly used by the farmers. The acute toxicity tests were conducted on Daphnia magna for two series of concentration ranges 100 ppm to 1000 ppm and 1000 ppm to 4000 ppm. The (Lethal Concentration) LC50 values for series 1 of Neemark and Tafgor were 522.86 ppm and 439.46 ppm, respectively, whereas it was 1840.48 ppm and 1335.97 ppm, respectively for for Series 2. A significant difference in the mortality rates between Neemark and Tafgor in the concentration range of 1000 ppm to 4000 ppm was observed (t = 2.483, p < 0.05). A combination treatment of Neemark and Tafgor in different proportions showed that the 2:1 v/v (Neemark: Tafgor) ratio showed the lowest toxicity with a LC50 value of 1067.78 ppm, suggesting its preferability in application on the field. Two–way ANOVA shows that the concentration of pesticides plays a significant role in the mortality of Daphnia (F = 19.729, p < 0.05) and so does the combination ratio treatment (F = 7.166, p < 0.05). These results suggest that these two factors along with the selection of a suitable plant-based pesticide play a critical role in the reduction in mortality rates of aquatic organisms.
Afficher plus [+] Moins [-]Chemical and Pathogen Impacts on Human Health near Aquaculture Areas in West Godavari District of Andhra Pradesh, India Texte intégral
2021
D. Nageswara Rao, T. Bhaskara Rao and P.V.S. Machiraju
Water is essential for all living organisms in the universe. Chemicals can cause contamination in groundwater near aquacultural activity areas. Keeping in view the hectic aquacultural activity in surrounding locations of Akividu town in West Godavari District of AP, India, it is proposed to assess the chemical and microbial contamination of waters to suggest remedial measures to protect the quality of water for safeguarding the health of the public residing in the nearby habitations who consume these waters for drinking purposes. 16 Groundwater samples were collected and analyzed for assessing the physicochemical parameters viz., pH, Electrical conductivity (EC), Total Dissolved solids (TDS), Total hardness (TH), Total Alkalinity (TA), Na+, K+, Calcium, Magnesium, Chloride, Sulphate, Nitrate and Phosphate, Irrigation parameters like %Na, SAR, KR RSC, and microbial analysis. The study results revealed that the samples were contaminated chemically and also with pathogenic bacteria like Pseudomonas, Citrobacter freundii and Escherichia coli which can cause water-borne diseases. Further, a health survey was carried out to verify the adverse effects to be caused by the chemical and microbial contamination of water on people’s health. The health survey results indicated the sufferings of the people who consume this water for drinking and domestic purposes. The waters are to be treated accordingly to control the chemical and bacterial contamination by using the available treatment methodologies before considering them for drinking purposes.
Afficher plus [+] Moins [-]Analysis on Pollution Hazards and Recycling Strategies of Logistics Packaging Wastes of E-Commerce Enterprises Texte intégral
2021
Zhongchao Hao
The emergence of China’s e-commerce industry leads to the rapid expansion of the express delivery industry, and the environmental pollution problem triggered by the express packaging wastes has become increasingly critical, severely impacting human health and sustainable social development. The literature regarding the pollution and recycling strategies of e-commerce logistics packaging wastes was first complied with and summarized in this work. Then, the research hypothesis of multi-subject (e-commerce enterprise, government, and third-party enterprises) in the recycling of e-commerce logistics packaging wastes was established. Finally, the effect of multi-subject participation in the recycling of e-logistics packaging wastes was surveyed via questionnaires using structural equation modeling. Results demonstrate that under the background of high-speed e-commerce development, the package pollution problem has become an important problem influencing environmental pollution in various countries across the world. The overall Cronbach’s alpha value of the questionnaires was 0.903, indicating good reliability. The observable variable- standard factor loading coefficient, was always greater than 0.5, indicating that the construct validity was accurate. Third-party and e-commerce enterprises played a significant positive role in the recycling effect of e-commerce logistics packaging wastes, with regression coefficients of 1.981 and 0.575, respectively. The government did not show any obvious influence on the recycling effect of e-commerce logistics packaging wastes. The pollution hazards of logistics packaging wastes of e-commerce enterprises can be effectively mitigated if e-commerce enterprises lead the green consumption needs, the government accelerates the perfection of laws and regulations related to the e-commerce logistics packaging, and a third-party professional recycling system is established, among others things. The study results will be of great reference significance for deeply analyzing the problems existing in the current express package pollution control and their causes, exploring the factors influencing the recycling effect of e-commerce logistics packaging wastes and enriching the multi-subject recycling strategies for express package pollution.
Afficher plus [+] Moins [-]Adsorption of U(VI) in Solution by Biochar and FeS Nanoparticles Texte intégral
2021
Xitong Zheng, Long Fu, Hao Deng, Keyuan Huang, Tianqi Liu, Yulin Deng, Jiaming Luo, Miao Xiang, Anjie Wang, Muqing Qiu, Li Han and Hai Wang
Uranium (U) is a common radionuclide in soil and groundwater. Uranium contamination often results from uranium mining and processing, nuclear energy power plants, nuclear weapon tests and nuclear accidents. Due to its toxicity and bioaccumulation, it was necessary to treat it effectively. Biochar and FeS nanoparticles were prepared for the treatment of U(VI) in solution. The characteristics of biochar and FeS nanoparticles were determined by Scanning Electron Microscopy, Energy Dispersive Spectrum and Fourier Transform Infrared Spectroscopy and BET adsorption method. The results showed that a large number of functional groups were present on the surface of biochar and FeS nanoparticles. The influencing factors, such as contact time, pH of the solution, initial concentration U(VI) and solution temperature, had an important influence on the adsorption capacity of U(VI) by biochar and FeS nanoparticles.
Afficher plus [+] Moins [-]Procuring Plant Services for Ecological and Human Well Being Texte intégral
2021
K. Saraswathi and K. Selvam
Ecosystem services offered by two native tree species viz. Azadirachta indica, Morinda tinctoria, and four exotic species viz. Tamarindus indica, Prosopis juliflora, Leucaena leucocephala, and Ipomoea carnea in the Mathippanur village of Madurai district, Tamil Nadu, India were assessed to augment their valuable ecosystem services and to get the management strategy for sustainable use. The selected plant species provide economic benefit through their products, regulating soil health, sequestering carbon, and supporting nests of animals. However, they cause discomfort to the associated vegetation and human beings. Both native and exotic species play a crucial role in the ecosystem and the removal of exotic species will lead to disturbance in the ecosystem resilience. For sustainable management, mixed plantations of tree species can be raised in barren and fallow lands. The plantations will aid in monetary support to the local inhabitants, people’s participation in resource management and conservation, and effective use of land and tree services.
Afficher plus [+] Moins [-]Fabrication of Ag/TiO2 Cotton Fabric to Enhance Photocatalytic Degradation of Anionic Dye Texte intégral
2021
S. Fu, Y. Dong, L. Liang and X. Meng
Ag/TiO2 composite fabric was prepared by coprecipitation with TiCl4 as a titanium source and AgNO3 as a silver source. The samples were characterized by scanning electron microscope (SEM), thermogravimetric analyzer (TG) and Fourier transform infrared spectrometer (FTIR). The photocatalytic activity of synthetic fabrics was measured by the degradation of anion dyes under ultraviolet light. The effects of silver loading concentration, fabric area, initial concentration, and photocatalytic time on photocatalytic activity were investigated. The experimental results showed that the degradation rate of Ag/TiO2 composite fabric on anion dyes could reach 70.76% in 50 minutes, indicating that the prepared Ag/TiO2 composite fabrics had high photocatalytic activity.
Afficher plus [+] Moins [-]Climate Responsive Strategy Matrix for Designing Buildings in India Texte intégral
2021
N. Thakur, D. Parashar, C. Chidambaram and M. Dharwal
The starting point for a good design of any building project is the analysis of the macroclimate and microclimate of the building site that encompasses an understanding of temperature, radiation, wind, precipitation, topography, vegetation, ground cover, etc., which together describe the site climate. Although urban context somewhat unifies, climate and topography prevalent in India are varied and diverse. Most part of the country is hot, while some regions are dry throughout the year, some are humid and some others are composite. The building design features, therefore, need to vary with the diversity to provide comfortable environments naturally. The context and the requirements for thermal comfort provide the basis for building siting, selection of building form and envelope, fenestration design, choice of materials, and other aspects. The paper proposes and discusses the various climate-responsive design strategies that are best adapted for the different climatic zones of India and presents such design interventions and features as a comparative matrix. Such a comparative presentation is novel, convenient, easy to comprehend, and provides a useful toolkit for building designers. The climate-responsive interventions in building design proposed in this study have the potential to enhance built environments naturally, thereby mitigating the adverse environmental impact. The proposed strategies are also validated through a sample field survey responded by building professionals from various climatic zones of the country.
Afficher plus [+] Moins [-]Removal of Various Contaminants by Highly Porous Activated Carbon Sorbent Derived from Agricultural Waste Produced in Malaysia - A Review Texte intégral
2021
N.Z. Zabi, W.N. Wan Ibrahim, N.S. Mohammad Hanapi and N. Mat Hadzir
This paper aims to review recent studies in preparing activated carbons from different types of agricultural wastes in Malaysia and how it can help Malaysia manage agricultural waste. It can be seen that most biomasses can be used as precursors to produce activated carbon for a wide range of pollutants and this adsorbent can be modified to optimally function depending on the types of pollutants. Under optimum dosages, modification through chemical activation using acidic, basic, or drying agents has significant effects on the selectivity of the analyte adsorption. The acidic activating agent causes the activated carbon to have negatively charged acid groups which enable it to adsorb cationic adsorbate while the basic activating agent causes the adsorbent to have a positive surface charge and enable it to adsorb anionic adsorbate.
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