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Resultados 3911-3920 de 8,010
Low Impact Development (LID) Practices: A Review on Recent Developments, Challenges and Prospects Texto completo
2021
Liu, Tianqi | Lawluvy, Yelly | Shi, Yang | Yap, Pow-Seng
Low impact development (LID) practices are able to mitigate the detrimental effects of urbanization and climate change due to their salient design features. LID can restore the hydrology of urban areas to the pre-development functions by using distributed stormwater control and natural hydrological features. LID can help to achieve the goal of sustainable development as it promotes effective urban stormwater management. This review covers a comprehensive list of LID practices, namely bioretention cell, green roof, infiltration trench, permeable pavement, rain barrel or cistern, rooftop disconnection and vegetative swale. For each type of the LID, the recent advances covering the aspects of principles, design, performance, advantages and disadvantages and costs are systematically reviewed. Additionally, although LID has been quite broadly applied and demonstrated success in urban stormwater management in many countries, there are still some main challenges during the implementation such as clogging and water quality. Meanwhile, this review also highlights the great opportunities for further developments for LID practices to realize their wider practical application. Finally, future research directions are provided in order to give critical insights into potential future works to advance this field of research.
Mostrar más [+] Menos [-]Coupling relationship between construction land expansion and PM2.5 in China Texto completo
2021
Zhou, Liang | Yuan, Bo | Mu, Haowei | Dang, Xuewei | Wang, Shaohua
Urban air pollution with PM₂.₅ as the main pollutant has become increasingly prominent in China since 2010. Scholars have conducted many studies on how urbanization affects PM₂.₅, but few concerns about the relationship between construction land (CL) expansion and PM₂.₅ at different scales from the perspective of expansion rate. Therefore, this study takes CL and PM₂.₅ data in China to describe the spatiotemporal progress of atmospheric environmental pollution and then adopts the overall and spatial coupling models to quantitatively reveal the dynamic relationship between them. The results indicate that the growth rate of PM₂.₅-polluted area in China was found to increase rapidly for 2000–2010 time period, followed by a continuous decline afterward. The annual average growth rates of CL area and PM₂.₅-polluted area within 15 years were 4.43% and 2.46%, respectively. Moreover, the barycenter distance between PM₂.₅ concentration and CL decreased gradually, and the two barycenters approached closer. Also, the spatial coupling coordination of CL and PM₂.₅ enhanced in Central, West, and East China but weakened in Northeast. Cities with a “very strong” coupling type are mainly located in the “Chongqing-Beijing” belt and the lower-middle reaches of the Yangtze River. Finally, the spatial coupling model results show that a low PM₂.₅ concentration is closely related to CL expansion. This study will provide a basis for cross-regional joint air pollution control and the management of heavily polluted areas in China.
Mostrar más [+] Menos [-]Synthesizing a Novel Zr/Fe/Al-Incorporated Cross-linked Chitosan as Absorbent for Effective Removal of Fluoride from Aqueous Solution Texto completo
2021
Li, Feng | Zhang, Yingting | Xu, Bo | Liu, Yongqiang | Qiu, Haiyan | Lan, Guihong | Xu, Qianxia
Zr/Fe/Al-modified chitosan beads were synthesized as a potential absorbent to remove fluoride on wastewater. In this study, the effects of solution pH, absorbent dosage, initial concentration, adsorption time, and coexisting ions were evaluated through a series of experiments. It was found that an adsorption capacity of 37.49 mg/g was achieved in the conditions with pH at 6.0, 1.6 g/L of the dose of CS-ZFA, 60 mg/L of fluoride concentration, and 120 min adsorption time. The adsorption results indicated that fluoride adsorption by CS-ZFA can be explained by Langmuir isotherm. Moreover, the kinetic studies indicated that the adsorption process was in good compliance with the pseudo-second-order kinetics and intra-particle diffusion model. The newly synthesized absorbents were characterized by SEM, EDS, FTIR, and TG analysis. Based on the characterization, the high adsorption capacity of the newly synthesized absorbent is due to the electrostatic attraction between amino and metal ions and the formation of CS-ZFA complex for fluoride. These excellent adsorption properties revealed that CS-ZFA is an effective absorbent for removing fluoride in aqueous solutions of environmental remediation.
Mostrar más [+] Menos [-]Antibiotic accumulation, growth performance, intestinal diversification, and function of Nile tilapia (Oreochromis niloticus) feed by diets supplemented with different doses of sulfamethoxazole Texto completo
2021
Fang, Longxiang | Chen, Xi | Shan, Xiangbao | Qiu, Liping | Fan, Limin | Meng, Shunlong | Song, Chao
To comprehensively investigate the effects of exposure to legal doses of sulfamethoxazole (SMZ) in Nile tilapia (Oreochromis niloticus), fishes were exposed to diets supplemented with different doses of SMZ (NS, normal feed; LS, 20 mg/kg·day; MS, 200 mg/kg·day; and HS, 1000 mg/kg·day) for 4 weeks and then fed with normal feed for 4 weeks. General SMZ accumulation, growth performance, intestinal short-chain fatty acids, intestinal flora diversity, composition, and function were systemically evaluated. Results indicated that the SMZ accumulation in O. niloticus muscles, intestinal contents, and aquaculture environment positively correlated to the exposure dose. The growth performance, measured by weight increase, was MS>LS>NS, while HS antibiotics retarded the growth. SMZ-exposed O. niloticus had an increased number of fat particles in the liver and a change in the content of intestinal SCFAs. Moreover, SMZ exposure changed the biological diversity of the intestinal flora and subsequently induced microbiota dysbiosis, primarily inhibiting the growth of Fusobacteria, especially in HS group. Overall, exposure to higher SMZ doses than the recommended ones impair general intestinal functions and provokes health risk in fish. This study highlights the importance of rational and regulated use of SMZ in aquaculture.
Mostrar más [+] Menos [-]Recent advances in physiological and molecular mechanisms of heavy metal accumulation in plants Texto completo
2021
Feki, Kaouthar | Tounsi, Sana | Mrabet, Moncef | Mhadhbi, Haythem | Brini, Faiçal
Among abiotic stress, the toxicity of metals impacts negatively on plants’ growth and productivity. This toxicity promotes various perturbations in plants at different levels. To withstand stress, plants involve efficient mechanisms through the implication of various signaling pathways. These pathways enhance the expression of many target genes among them gene coding for metal transporters. Various metal transporters which are localized at the plasma membrane and/or at the tonoplast are crucial in metal stress response. Furthermore, metal detoxification is provided by metal-binding proteins like phytochelatins and metallothioneins. The understanding of the molecular basis of metal toxicities signaling pathways and tolerance mechanisms is crucial for genetic engineering to produce transgenic plants that enhance phytoremediation. This review presents an overview of the recent advances in our understanding of metal stress response. Firstly, we described the effect of metal stress on plants. Then, we highlight the mechanisms involved in metal detoxification and the importance of the regulation in the response to heavy metal stress. Finally, we mentioned the importance of genetic engineering for enhancing the phytoremediation technique. In the end, the response to heavy metal stress is complex and implicates various components. Thus, further studies are needed to better understand the mechanisms involved in response to this abiotic stress.
Mostrar más [+] Menos [-]Developing and validating the Malay version instrument to assess knowledge, attitudes and practices regarding second-hand smoke in the workplace: a cross-sectional study in teaching hospital in Malaysia Texto completo
2021
Rashiden, Ikmal | Ahmad Tajuddin, Nur Amani Natasha | Yee, Anne | Amer Nordin, Amer Siddiq
This research sought to develop and validate the “Workplace Second-hand Smoke: Perception on the SHS Knowledge, Attitude, and Practice” (WSHS: PAP) instrument, which targets non-smoking employees. A cross-sectional study was conducted between April and June 2018 to validate WSHS: PAP among non-smoking employees at Universiti Malaya Medical Centre (UMMC). Experts were invited to validate the instrument. Then, for exploratory factor analysis, a cross-sectional study was conducted among 336 UMMC non-smoking employees who were recruited by convenience sampling. A total of 28 items on KAP, rated on five-point Likert scales, underwent exploratory factor analysis and were tested for internal consistency (Cronbach’s alpha). Participants were approached after 2 weeks for the assessment of test-retest reliability. Cronbach’s alpha was 0.828, 0.743 and 0.837, respectively, for the domains of perception of the knowledge, attitude and practice, indicating acceptable internal consistency (above 0.7). Exploratory factor analysis identified a one-factor solution for each of the KAP domains. Therefore, the Malay version of the WSHS: PAP instrument demonstrated satisfactory psychometric properties for the assessment of non-smoking employees in workplaces with a smoking ban.
Mostrar más [+] Menos [-]Abatement potential and cost of agricultural greenhouse gases in Australian dryland farming system Texto completo
2021
Tang, Kai | Wang, Mingzhe | Zhou, Di
Evaluating the cost-effectiveness of GHG mitigation in the dryland agricultural sector is needed in terms of designing and implementing detailed and efficient mitigation programs, which is currently rarely covered by the literature. In this paper, we use a parametric directional distance approach to explore the farm-level abatement potential and cost (shadow value) of GHG for dryland farms in southwestern Australia. The study indicates that dryland agriculture could abate substantial GHG emissions and save agricultural inputs simultaneously. For the years 2006–2013, the average abatement potential ratios fluctuated between 17 and 33%, with a mean value of 21%. The mean shadow price of dryland agricultural GHG was $17.60 per tonne CO₂-e in 2013 Australian dollars. In general, the analysis supports that reducing GHG in dryland agriculture is relatively cost-effective.
Mostrar más [+] Menos [-]Environmental degradation in ASEAN: assessing the criticality of natural resources abundance, economic growth and human capital Texto completo
2021
Nathaniel, Solomon Prince
The ASEAN countries have enjoyed significant economic advancement over the years. The region is also blessed with lots of natural resources. However, natural resource abundance and economic growth could contribute to environmental deterioration, especially when the exploration and consumption of natural resource is not sustainable. This study has a maiden attempt to constitute the dynamic linkages between natural resources, human capital, economic growth, and ecological footprint (EF) in ASEAN. The Augmented Mean Group (an advanced econometric estimator) is adopted for empirical analysis over the period 1990 to 2016. The findings confirm the adverse effect of economic growth and natural resource on environmental quality. Human capital, though with a negative coefficient, is not efficient in mitigating environmental degradation in ASEAN. The country-wise results affirm that economic growth intensifies environmental degradation in all the countries, and the outcome was consistent with the dynamic OLS results. Further findings from the country-wise results suggest that natural resource is not harmful in Laos PDR and Thailand, but constitute environmental deterioration in the other countries. Finally, a feedback causality is discovered between natural resource and economic growth, and between human capital and economic growth. The limitations of the study and directions for future research have been highlighted along with relevant policy directions.
Mostrar más [+] Menos [-]Spatiotemporal distribution of boron in the groundwater and human health risk assessment from the coastal region of Bangladesh Texto completo
2021
Rahman, Mahfuzur | Tushar, Mahmud Al Noor | Zahid, Anwar | Ahmed, Kazi Matin Uddin | Siddique, Mohammad Abdul Momin | Mustafa, M Golam
High concentrations of naturally-occurring and man-accentuated boron in groundwater possess a potential threat to the health and well-being of humans worldwide. In Bangladesh, only a few studies focused on the health risks of boron-containing groundwater. Therefore, the present study investigated the spatiotemporal distribution of boron concentrations in groundwater and its associated health risks in the coastal districts of Bangladesh. A total of 268 samples from the shallow and deep wells during the wet and dry season (137 and 131 samples, respectively) were collected to determine the level of boron concentrations and health risk status. The groundwater boron concentrations ranged from 0 to 4.10 mg/L with an average concentration of 0.68 mg/L, which was much lower than the WHO and the values of Bangladesh drinking water standard guideline. The boron concentrations in the shallow wells override the deep ones with insignificant seasonal variation. Boron contamination affected 10% of the shallow wells in the wet season and only 6% of them in the dry season, whereas only 1% of deep wells exceeds the WHO guideline values of 2.40 mg/L during the wet and dry season, respectively. The human health risk of boron was determined by computing estimated daily intake (EDI) and hazard quotient (HQ) values for infants, children, teenagers, and adults. The average HQ value delimitated that children have high risk followed by teenagers, adults, and infants. About 90–95% of the studied samples were free from boron contamination because of having HQ values < 1 and the rest of the samples possess a high risk for children. For the overall study area, the deep wells were found safer than the shallow wells, which were more susceptible to boron contamination aided by localized freshwater inputs.
Mostrar más [+] Menos [-]An empirical investigation of nuclear energy and environmental pollution nexus in India: fresh evidence using NARDL approach Texto completo
2021
Syed, Aamir Aijaz | Kamal, Muhammad Abdul | Tripāṭhī, Ravīndra
Environmental pollution caused by carbon emissions is an emerging issue to study among researchers. The nexus between environmental pollution and carbon emissions has motivated researchers to evaluate the impact of cleaner energy on carbon emissions. This study further contributes to the research by examining the above relationship by studying the asymmetric influence of nuclear energy (NE), industrial productivity (IP), and economic growth rate (GDP) on carbon emissions (CO₂) in India from 1975 to 2018 using the asymmetric autoregressive distribution lag approach. The results of the bound test and the Wald test show that in the long run, there is an asymmetric relationship between CO₂, NE, GDP, and IP, and in the short run, there is a symmetric relationship between CO₂, GDP, and IP. The result implies that increased usage of nuclear energy over fossil fuels and improvement in industrial productivity, in the long run, reduces CO₂ emission in India. Furthermore, the study concludes that the government should consider the asymmetric relationship between the variables and devise appropriate policies to increased nuclear energy and industrial productivity in India for environmental sustainability.
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