خيارات البحث
النتائج 5001 - 5010 من 6,560
Reactivity of vadose-zone solids to S-metolachlor and its two main metabolites: case of a glaciofluvial aquifer النص الكامل
2020
Sidoli, Pauline | Devau, Nicolas | Jaramillo, Rafael Angulo | Baran, Nicole
Reactivity of vadose-zone solids to S-metolachlor and its two main metabolites: case of a glaciofluvial aquifer النص الكامل
2020
Sidoli, Pauline | Devau, Nicolas | Jaramillo, Rafael Angulo | Baran, Nicole
The vulnerability of groundwater to pesticides is governed in part by sorption mechanisms in the vadose zone, commonly studied in soil but less well-known in the geological solids. To alleviate this lack of knowledge, adsorption of the herbicide S-metolachlor (SMOC) and of two of its metabolites—metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA)—was studied with batch equilibrium method on seventeen surface soils and three geological solids of the vadose zone overlying a glaciofluvial aquifer. In grainsize terms, the latter three were sand for the first two samples and gravel for the third. Adsorption is ordered as follows: SMOC > > MESA > MOXA, except for one of the geological solids for which MESA adsorption was slightly higher than that of SMOC (Kd = 0.73 vs. 0.44 L kg⁻¹). The low MOXA adsorption could only be quantified for the gravel sample (Kd = 0.74 L kg⁻¹), which was also more reactive than all the other samples to MESA and SMOC (Kd = 2.08 and 28.8 L kg⁻¹, respectively). Statistical multivariate tests related the highest Kd values for SMOC with the soils and geological solids with the highest organic-carbon and clay-fraction contents. The highest Kd values for MESA were found in the samples containing high oxide concentrations. Our results shed a new light on the adsorption of SMOC, MESA and MOXA suggesting that during their transfer to groundwater, pesticides and metabolites can be adsorbed in the vadose zone on both soils and geological solids.
اظهر المزيد [+] اقل [-]Reactivity of vadose-zone solids to S-metolachlor and its two main metabolites: case of a glaciofluvial aquifer النص الكامل
2020
Sidoli, Pauline | Devau, Nicolas | Jaramillo, Rafael Angulo | Baran, Nicole
The vulnerability of groundwater to pesticides is governed in part by sorption mechanisms in the vadose zone, commonly studied in soil but less well-known in the geological solids. To alleviate this lack of knowledge, adsorption of the herbicide S-metolachlor (SMOC) and of two of its metabolites—metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA)—was studied with batch equilibrium method on seventeen surface soils and three geological solids of the vadose zone overlying a glaciofluvial aquifer. In grainsize terms, the latter three were sand for the first two samples and gravel for the third. Adsorption is ordered as follows: SMOC > > MESA > MOXA, except for one of the geological solids for which MESA adsorption was slightly higher than that of SMOC (Kd = 0.73 vs. 0.44 L kg−1). The low MOXA adsorption could only be quantified for the gravel sample (Kd = 0.74 L kg−1), which was also more reactive than all the other samples to MESA and SMOC (Kd = 2.08 and 28.8 L kg−1, respectively). Statistical multivariate tests related the highest Kd values for SMOC with the soils and geological solids with the highest organic-carbon and clay-fraction contents. The highest Kd values for MESA were found in the samples containing high oxide concentrations. Our results shed a new light on the adsorption of SMOC, MESA and MOXA suggesting that during their transfer to groundwater, pesticides and metabolites can be adsorbed in the vadose zone on both soils and geological solids.
اظهر المزيد [+] اقل [-]Short-term effects of particulate matter exposure on emergency room visits for cardiovascular disease in Lanzhou, China: a time series analysis النص الكامل
2020
Chen, Rui | Gao, Qian | Sun, Jianyun | Yang, Haixia | Li, Yongjun | Kang, Fenyan | Wu, Wei
Cardiovascular disease (CVD) has been the leading cause of death in China. Identifying the relationship between particulate matter (PM) and CVD in China is a significant challenge. In this study, daily CVD emergency room visit, environmental monitoring, and weather data from January 1, 2017, to December 31, 2018, in Lanzhou were collected. Generalized additive models (GAMs) were constructed to estimate the short-term effects of daily PM₂.₅, PMC, and PM₁₀ concentrations on CVD emergency room visits with different lag structures after controlling for the influence of meteorological elements and gaseous pollutants. Stratified analyses were conducted according to age (≥ 65 years and < 65 years), sex (male and female), cold season (from November to April), and warm season (from May to October). The results showed that each 10 μg/m³ increase in PM₂.₅ was associated with a 1.93% (95% CI 0.12–3.78%) increase in CVD emergency room visits at lag03, and no single lag model was statistically significant. The excess relative risks (ERRs) of PM₁₀ and PMC were not statistically significant at any lag pattern. The exposure-response curves demonstrated a nonlinear upward trend for these three PM pollutants. When adjusting for other gaseous pollutants, such as NO₂, SO₂, CO, and O₃, in the two-pollutant models, the associations between PM₁₀ and PMC and CVD emergency room visits did not change compared with the single-pollutant models. The ERRs of PM₂.₅ were 1.67% (95% CI 0.03–3.34%) at lag02 after adjustment for NO₂ and 1.65% (95% CI 0.02–3.30%) at lag02 after adjustment for SO₂. The ERRs of PM₂.₅ were still statistically significant at lag03 when we adjusted for any one of the gaseous pollutants. Susceptibility to PM₂.₅ was increased in people aged < 65 years, in males, and in the warm season. The findings are very important for local governments to develop environmental policies and strategies to reduce ambient PM₂.₅ levels.
اظهر المزيد [+] اقل [-]Part XIII: Sampling and Analysis of Litterfall النص الكامل
2020
Ukonmaanaho, Liisa | Pitman, Rona | Bastrup-Birk, Annemarie | Bréda, Nathalie | Rautio, Pasi | Finnish Forest Research Institute (METLA) ; Natural Resources Institute Finland (LUKE) | Forest Research, Alice Holt Lodge | European Environment Agency (EEA) | SILVA (SILVA) ; AgroParisTech-Université de Lorraine (UL)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Natural Resources Institute Finland (LUKE) | UNECE ICP Forests | UNECE ICP Forests Programme Co-ordinating Centre (ed.)
International audience | This part of the Manual aims to provide sufficient methodological advice to allow participating National Focal Centres to sample and prepare an accurate measurement of the quantity and quality of litterfall, from selected plots of the ICP Forests intensive monitoring system. Harmonization of procedures of collection and chemical analysis is essential to ensure comparability of the chemical composition of litterfall, and accurate assessment of LAI. Only data obtained by the methodologies described in this chapter will be accepted for submission into the international database of the ICP Forests programme.
اظهر المزيد [+] اقل [-]Identifying knowledge levels of aquaponics adopters النص الكامل
2020
Greenfeld, Asael | Becker, Nir | Bornman, Janet F. | Angel, Dror L.
Aquaponics or the integration of aquaculture and hydroponic farming, is a sustainable food production system that is currently popular more as a hobby rather than on commercial scales. Recent increase in scientific and public interest in aquaponics and its environmental benefits supports research that addresses technical, economic, and legislative barriers to wider adoption of these systems. A successful combination of hydroponics with an aquaculture system requires high levels of knowledge and skill that are not necessarily available to all aquaponic practitioners. In this short communication, we analyzed the results of a worldwide survey of commercial aquaponic growers’ statements about their own knowledge base. Most respondents (59%) had some relevant prior knowledge. Surprisingly, many respondents (41%) claimed to have insufficient knowledge of both fish and plants in their first year of operating a commercial aquaponics system. We interpret this as a rough indication that about a third of the new aquaponic businesses are started by entrepreneurs who are not farmers and have no prior training or experience in growing fish or plants. If aquaponics is to become a more widespread commercially viable enterprise and be capable of delivering its environmental benefits, its promotion must consider the importance of prior knowledge held by entrepreneurs entering aquaponics.
اظهر المزيد [+] اقل [-]Temporal stability of E. coli and Enterococci concentrations in a Pennsylvania creek النص الكامل
2020
Jeon, Dong Jin | Pachepsky, Yakov | Coppock, Cary | Harriger, M Dana | Zhu, Rachael | Wells, Edward
Microbial quality of irrigation waters is a substantial food safety factor. Escherichia coli (E. coli) and Enterococci are used as the fecal indicator bacteria (FIB) to assess microbial water quality. Analysis of temporally stable patterns of FIB can facilitate effective monitoring of microbial water quality. The objectives of this study were (1) to investigate the spatiotemporal variation of E. coli and Enterococci concentrations in a large creek traversing diverse land use areas and (2) to explore the presence of temporally stable FIB concentration patterns along the creek. Concentrations of both FIB were measured weekly at five water monitoring locations along the 20-km long creek reach in Pennsylvania at baseflow for three years. The temporal stability was assessed using mean relative deviations of logarithms of FIB concentration from the average across the reach measured at the same time. The Spearman rank correlation coefficients between logarithms of FIB concentrations on consecutive sampling times was another metric used to assess the temporal stability of FIB concentration patterns. Logarithms of FIB concentrations had sinusoidal dependence on time and significantly correlated with temperature at all locations Both FIB exhibited temporal stability of concentrations. The two most downstream locations in urbanized areas tended to have logarithms of concentrations higher than the average along the observation reach. The location in the upstream forested area had mostly lower concentrations (log E. coli 1.59, log Enterococci 1.69) than average (log E. coli 2.07, log Enterococci 2.20). concentrations in colony-forming units (CFU) (100 mL)⁻¹. Two locations in the agricultural and sparsely urbanized area had these logarithm values close to the average. The temporal stability was more pronounced in cold seasons than in warm seasons. No significant difference was found between pattern determined for each of three observation years and for the entire three-year observation period. The Spearman rank correlations between observations on consecutive dates showed moderate to very strong relationships in most cases. Existence of the temporal stability of FIB concentrations in the creek indicates locations that inform about the average logarithm of concentrations or the geometric mean concentrations along the entire observation reach.
اظهر المزيد [+] اقل [-]Does asymmetric persistence in convergence of the air quality index (AQI) exist in China? النص الكامل
2020
Zhang, Xue-Tao | Liu, Xi-Hua | Su, Chi-Wei | Umar, Muhammad
In recent years, China’s air pollution has caused significant concern in the academia. China is the hub of business and financial activities, with the most populous cities. It is important to determine the convergence and asymmetric persistence of air quality index (AQI hereafter) in China to achieve sustainable development goals, especially the ones related to the environment. This paper uses the Fourier quantile unit root test to check for inter-regional convergence of monthly AQI for 74 cities across China from January 2013 to July 2019. For a comparative baseline analysis, five conventional univariate and quantile unit root tests are also conducted. The empirical outcomes show that the Fourier quantile unit test exhibits a significant advantage in detecting smooth breaks and evaluating the asymmetric behavior and mean-reverting properties of AQI. Moreover, the monthly AQI in 70 out of 74 C0hinese cities are stationary processes. These findings not only focus on the appropriate use of relevant modeling techniques of smooth breaks and asymmetries in the AQI series of the 74 Chinese cities but also provide crucial environmental sustainability and economic implications for AQI regulation policies.
اظهر المزيد [+] اقل [-]Stable isotopes reveal effects of natural drivers and anthropogenic pressures on isotopic niches of invertebrate communities in a large subtropical river of China النص الكامل
2020
Wang, Sai | Su, Lin-Hui | Luo, Bang-Ke | Qin, Ying-Jun | Stewart, Simon D. | Tang, Jin-Peng | Wang, Tuan-Tuan | Yang, Yang | Cheng, Gong
Isotopic niches reflect the basic structure and functioning of river food webs; however, their response to riverine environments remains unclear. We used stable isotope analysis and community-wide metrics to quantify how invertebrate niches vary with environmental changes along a large subtropical river in China. Eight niche metrics, which had higher values in the wet than in the dry season, increased from headwaters to the middle river and decreased sharply near the estuarine industrial zones. The δ¹³C value of > − 23.8‰, which indicated consumption of epilithic diatoms, separated the invertebrates between the upper and mid-lower reaches. The δ¹⁵N values > 9.4‰ identified site-specific nitrogen sources from manure (e.g., animal effluent) and domestic sewage in agricultural area. The output of mixing models showed a downstream shift in carbon utilization by invertebrates from autochthonous periphyton and submerged hydrophytes to allochthonous C3 plants. Principle component (PC) and cluster analysis decomposed and grouped 40 environmental variables into 4 PCs that explained 84.5% of the total variance. Hierarchical partitioning revealed that the second and first PCs, which were driven mainly by biological indicators and habitat characteristics, had the highest explanatory power for niche ranges and areas (e.g., Bayesian ellipse), respectively. Our results suggest that reducing anthropogenic pressures (e.g., habitat loss and water pollution) on river ecosystems through measures, such as protecting diatom-dominated biofilms in riffles and controlling nitrogen loading in rural regions, may produce the greatest impact for river management. Graphical abstract
اظهر المزيد [+] اقل [-]Impact of fiscal decentralization on firm environmental performance: evidence from a county-level fiscal reform in China النص الكامل
2020
Wen, Huwei | Lee, Chien-Chiang
To promote county economic prosperity and social development, China enacted a fiscal reform known as “province governing county” (PGC) in the early 2000s. Using the difference-in-differences (DID) method and a massive sample of enterprises from 2003 to 2011, this study investigates the effect of PGC reform on firm environmental performance. The results show that enterprises in reformed counties have significantly decreased their pollution intensity since the fiscal reform. Our research reveals that the environmental effects of fiscal decentralization are related to changes in the political assessment metrics of local officials. It also shows that PGC fiscal reform has a significant positive effect on the environmental performance of large, small, and micro enterprises. Furthermore, it suggests that PGC fiscal reform benefits the environmental performance due to the informational advantages of county governments. In terms of environmental governance, although local governments have an information advantage in the allocation of green fiscal funds, well-designed mechanisms are needed to strengthen their motivation.
اظهر المزيد [+] اقل [-]The effects of emission trading system on corporate innovation and productivity-empirical evidence from China’s SO2 emission trading system النص الكامل
2020
Tang, Hong-li | Liu, Jian-min | Mao, Jun | Wu, Jin-guang
Emission trading system is a significant market-based environmental regulation tool worldwide. This study fills existing knowledge gap on whether ETSs have “weak” and “strong” version of Porter hypothesis effects in China, by examining the effects of the Chinese SO₂ emission trading on corporate innovation and productivity. Using the micro-data of domestic-listed manufacturing companies from 2004 to 2015, this study regarded China’s SO₂ emission trading system as a quasi-natural experiment by applying a difference-in-difference framework to eliminate endogenous problems. It was found that the SO₂ emission trading system significantly promoted corporate innovation but did not have a significant effect on corporate productivity. The cause analysis showed that suboptimal institutional context and lack of corporate dynamic response led to the failure of strong Porter hypothesis effect. In addition, small- and medium-sized enterprises and non-state-owned enterprises gained greater innovation compensation effects of the emission trading system. This research believed that, the design, institutional context, and market incentives of emission trading systems need to be improved from the top down, to achieve the dual goal of environmental sustainability and economic growth.
اظهر المزيد [+] اقل [-]A novel anammox reactor with a nitrogen gas circulation: performance, granule size, activity, and microbial community النص الكامل
2020
Chen, Wenjing | Chen, Shengdong | Hu, Fan | Liu, Wenru | Yang, Dianhai | Wu, Jun
Anammox process was regarded to be one of the vital links to achieve energy-saving or energy-producing wastewater treatment plant. In the study, an anammox reactor with the nitrogen gas circulation was constructed to culture anammox granules, and the performance, granule size distribution, and microbial community were investigated. Dissolved oxygen loading is found to be an important factor for the start-up of the anammox process, and the nitrogen removal rate of 2.12 kg N m⁻³ day⁻¹ was achieved under the average nitrogen loading rate of 2.6 kg N m⁻³ day⁻¹. The activity test showed that the highest specific anammox activity of 345.9 mg N gVSS⁻¹ day⁻¹ was achieved for granules with size of 0.5–1.0 mm. The Illumina high-throughput sequencing analysis revealed the consistent variation of Candidatus Brocadia and Denitratisoma abundance in granues of all sizes, suggesting possible synergistic mechanism between heterotrophic bacteria Denitratisoma and anammox bacteria Ca. Brocadia. Furthermore, the results indicated the reactor with the nitrogen gas circulation is an efficient strategy to start-up anammox.
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