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Результаты 3211-3220 из 4,924
Analysis of rainfall infiltration and its influence on groundwater in rain gardens
2019
Li, Jiake | Li, Fan | Li, Huaien | Guo, Chao | Dong, Wen
The dynamic observation data on groundwater level and water quality were obtained from rain gardens #2 and #3 from May to October 2016. The water balance method and 2D numerical simulation of variable saturation zone were used to calculate rainfall infiltration recharge coefficient, water supply, and evaporative discharge of rain garden. These parameters were used to simulate and explore the impact of rainfall infiltration in rain gardens on groundwater level and water quality. The groundwater depth of rain gardens was mainly affected by the concentrated infiltration of rainfall. The variation range of groundwater depth was approximately 4.298 ± 0.031 mm for J1, 3.9364 ± 0.097 mm for J2, and 4.0958 ± 0.064 mm for J3, and the specific yield was 0.208. Groundwater quality was naturally attenuated and would not threaten the safety of groundwater at a certain scale. Visual MODFLOW was used to simulate groundwater flow and conduct parameter sensitivity analysis to determine the main influencing factors of garden groundwater level change. Results showed that rainfall recharge was crucial to module sensitivity.
Показать больше [+] Меньше [-]Toxic effect of different types of titanium dioxide nanoparticles on Ceriodaphnia dubia in a freshwater system
2019
Iswarya, Velu | Palanivel, Abirami | Chandrasekaran, Natarajan | Mukherjee, Amitava
In the current study, the effect of different types of titanium dioxide (TiO₂) nanoparticles (NPs) (rutile, anatase, and mixture) was analyzed on Ceriodaphnia dubia in the presence of algae under distinct irradiation conditions such as visible and UV-A. The toxicity experiments were performed in sterile freshwater to mimic the chemical composition of the freshwater system. In addition, the oxidative stress biomarkers such as MDA, catalase, and GSH were analyzed to elucidate the stress induced by the NPs on daphnids. Individually, both rutile and anatase NPs induced similar mortality under both visible and UV-A irradiations at all the test concentrations except 600 and 1200 μM where rutile induced higher mortality under UV-A. Upon visible irradiation, the binary mixture exhibited a synergistic effect at their lower concentration and an additive effect at higher concentrations. In contrast, UV-A irradiation demonstrated the additive effect of mixture except for 1200 μM which elucidated antagonistic effect. Mathematical model confirmed the effects of the binary mixture. The surface interaction between the individual NPs in the form of aggregation played a pivotal role in the induction of specific effects exhibited by the binary mixture. Oxidative stress biomarkers were highly increased upon NPs exposure especially under visible irradiation. These observations elucidated that the irradiation and crystallinity effect of TiO₂ NPs were noted only on certain biomarkers and not on the mortality.
Показать больше [+] Меньше [-]Enhanced arsenate removal from aqueous solution by Mn-doped MgAl-layered double hydroxides
2019
Li, Shifeng | Guo, Yang | Xiao, Min | Zhang, Tan | Yao, Shuhua | Zang, Shuyan | Fan, Hongtao | Shen, Yanming | Zhang, Zhigang | Li, Wenxiu
In this study, Mn-doped MgAl-layered double hydroxides (LDHs) were successfully synthesized for efficient removal arsenate from aqueous solution. The structure and composition of Mn-doped MgAl-LDHs intercalated by different ions such as CO₃²⁻, Cl⁻, or NO₃⁻ were investigated. The characterizations of XRD, ATR FT-IR, SEM, TG-DTA, and N₂ adsorption-desorption presented that the Mn-doped MgAl-LDHs (donated as Mn-LDHs) have very similar physical morphologies and properties to the MgAl-Cl-LDHs (donated as Mg-LDHs). However, the Mn-LDHs exhibits more preferable arsenate adsorption than Mg-LDHs. The As(V) removal kinetics data of Mn-LDHs is followed pseudo-second-order expression. The adsorption capacity of As(V) on Mn-LDHs via Langmuir isotherm model was 166.94 mg g⁻¹. The results of XPS revealed that the enhanced removal mechanism can be attributed to surface complexation of As(V) with Mn on the surface of Mn-LDHs. These results prove that Mn-doped LDHs can be considered as a potential material for adsorption As(V) from wastewater.
Показать больше [+] Меньше [-]Using multi-integrated biomarker indexes approach to assess marine quality and health status of marine organism: a case study of Ruditapes philippinarum in Laizhou Bay, China
2019
Ji, Rongwang | Pan, Luqing | Guo, Ruiming | Zheng, Lei | Zhang, Mengyu
With the progress of technology and the deepening of understanding of biological monitoring, much more attention has been paid to the multiple evaluation of marine pollution monitoring. In view of this, our study aimed at establishing a multi-integrated biomarker indexes approach to evaluate marine condition systematically and comprehensively. In the current study, sampling was conducted in Laizhou Bay, China (S1, S2, and S3) in May, August, and October of 2015. And then, multi-integrated biomarker indexes approach was applied to assess marine PAHs pollution, select appropriate biomarkers, and evaluate marine environmental quality and health status of the clams of Ruditapes philippinarum. As the results showed, S2 was the most PAHs-polluted site while S1 was the least polluted site, and the levels of tPAHs in seawater and sediments ranged from 69.78 to 315.30 ng/L and 163.19 to 565.17 ng/g d.w., respectively. And all three sampling sites had different sources of PAHs. IBR represented DNA damage (F value), the expression of SOD, EROD activity, GST activity, and LPO could be served as biomarkers to monitor the PAHs pollution in Laizhou Bay. And MPI suggested the quality of all three sites: S1 was generally favorable, S2 was moderately polluted, and S3 was lightly polluted. BRI values showed that the order of health status of R. philippinarum was S1 > S3 > S2.
Показать больше [+] Меньше [-]Acute effects of UVB radiation on the survival, growth, development, and reproduction of Daphniopsis tibetana Sars (Crustacea: Cladocera)
2019
Wang, Meiru | Zhao, Wen | Wei, Jie | Wang, Shan | Xie, Xi
Daphniopsis tibetana Sars lives in elevation, usually with strong solar UV radiation. We speculate that UV may have an effect on the ecology and evolutionary biology of this species. However, the regulatory effect and mechanism of UV on D. tibetana have not been studied previously. Here, our results showed that UVB could act as a positive factor in the relative body lengths, reproductive parameters, and population growth parameters of D. tibetana when UVB radiation is 20–170 mJ cm⁻², compared with the control group. Strikingly, these parameters were highest at 120 mJ cm⁻². To explore the mechanism underlying the UVB irradiation effects, we conducted a transcriptome analysis using the Trinity platform. The results indicated that differentially regulated genes were mostly enriched in lipid transport and lipid localization by Gene Ontology (GO) enrichment analysis of 146 differentially expressed genes (83 upregulated and 63 downregulated). This is the first study of UVB radiation of D. tibetana to reveal genes that may have crucial roles in survival, growth, and reproduction and could be candidates for future functional studies. Additionally, the study could supply a substantial resource for investigating and elucidating lipids that could play important roles in a physiological context.
Показать больше [+] Меньше [-]Long-term observation of cyanobacteria blooms using multi-source satellite images: a case study on a cloudy and rainy lake
2019
Mu, Meng | Wu, Chuanqing | Li, Yunmei | Lyu, Heng | Fang, Shengzhong | Yan, Xiang | Liu, Ge | Zheng, Zhubin | Du, Chenggong | Bi, Shun
High-frequency and reliable data on cyanobacteria blooming over a long time period is crucial to identify the outbreak mechanism of blooms and to forecast future trends. However, in cloudy and rainy areas, it is difficult to retrieve useful satellite images, especially in the rainy season. To address this problem, we used data from the HJ-1/CCD (Chinese environment and disaster monitoring and forecasting satellite/charge coupled device), GF-1/WFV (Chinese high-resolution satellite/wide field of view), and Landsat-8/OLI (Operational Land Imager) satellites to generate a time series of the bloom area from 2009 to 2016 in Dianchi Lake, China. We then correlated the responses of bloom dynamics to meteorological factors. Several findings can be drawn: (1) a higher bloom frequency and a larger bloom area occurred in 2011, 2013, and 2016, compared to the other years; (2) the frequency of blooms peaked in April, August, and November each year and expanded from north to south starting in July; (3) air temperature in spring and sunshine hours in summer greatly correlated to the yearly bloom area; (4) wind speed and sunshine hours strongly affected the short-term expansion of blooms and thereafter influenced the monthly bloom scale; and (5) rainfall had a strong short-term influence on the occurrence of blooms. Cyanobacteria blooms often occurred when wind speeds were less than 2.35 ± 0.78 m/s in the dry season and 2.01 ± 0.75 m/s in the rainy season, when there were 48 to 72 h of sunshine in the dry season and 35 to 57 h of sunshine in the rainy season, and when there was more than 10 mm of daily precipitation.
Показать больше [+] Меньше [-]A relative risk assessment of the open burning of WEEE
2019
Cesaro, Alessandra | Belgiorno, V. | Gorrasi, Giuliana | Viscusi, Gianluca | Vaccari, Mentore | Vinti, Giovanni | Jandric, Aleksander | Dias, M. Isabel | Hursthouse, Andrew | Salhofer, Stefan
Waste electric and electronic equipment (WEEE) represents a potential secondary source of valuable materials, whose recovery is a growing business activity worldwide. In low-income countries, recycling is carried out under poorly controlled conditions resulting in severe environmental pollution. High concentrations of both metallic and organic pollutants have been confirmed in air, soil, water, and sediments in countries with informal recycling areas. The release of these contaminants into the environment presents a risk to the health of the exposed population that has been widely acknowledged but still needs to be quantified. The aim of this work was to evaluate the relative risk from inhalation associated with the open burning of different kinds of WEEE. The shrinking core model was applied to estimate the concentration of the metals which would be released into the environment during the incineration of different types of WEEE. In addition, the potential generation of dioxins during the same informal practice was estimated, based on the plastic content of the WEEE. The results provided for the first time a comparative analysis of the risk posed from the open burning of WEEE components, proposing a methodology to address the absolute risk assessment to workers from the informal recycling of WEEE.
Показать больше [+] Меньше [-]Exposure to polycyclic aromatic hydrocarbons and risk of disability among an elderly population
2019
Chen, Yuan-Yuei | Kao, Tung-Wei | Wang, Chung-Ching | Chen, Ying-Jen | Wu, Zhenrong | Lai, Ching-Huang | Chen, Wei-Liang
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants. Exposure to PAHs is associated with several adverse health outcomes. However, no previous study has examined the relationship between PAH exposure and functional dependence in an elderly population. Our aim was to examine whether PAH exposure was associated with functional dependence including total disability, activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activities (GPA) in an elderly population. A total of 5816 elderly adults from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2006 were examined. PAH exposure was measured by urinary biomarkers. Functional dependence was assessed by 19 structured questions. The association between PAH exposures with functional dependence was performed by using a multivariable linear regression model. After adjusting for pertinent variables, positive associations were observed between the total number of disabilities and 2-naphthalene and 1-pyrene quartiles (all Pₜᵣₑₙd < 0.05). There was a dose-dependent relationship between 1-pyrene quartiles and all functional dependence domains, and the higher quartile of 1-pyrene was more closely associated with functional impairment (all Pₜᵣₑₙd < 0.05). PAH exposure is associated with functional dependence in American elderly adults. Future research is needed to bring to light the pathophysiological underlying mechanisms related to these findings.
Показать больше [+] Меньше [-]Direct micro-electric stimulation alters phenanthrene-degrading metabolic activities of Pseudomonas sp. strain DGYH-12 in modified bioelectrochemical system
2019
Wang, Xingbiao | Wan, Guilong | Shi, Liuyang | Gao, Xiaolong | Zhang, Xiaoxia | Li, Xiaoguang | Zhao, Jianfang | Sha, Beibei | Huang, Zhiyong
Bioelectrochemical systems (BESs) have great potential for treating wastewater containing polycyclic aromatic hydrocarbons (PAHs); however, detailed data on cell physiological activities in PAH biodegradation pathways stimulated by BESs are still lacking. In this paper, a novel BES device was assembled to promote the growth of Pseudomonas sp. DGYH-12 in phenanthrene (PHE) degradation. The results showed that in the micro-electric field (0.2 V), cell growth rate and PHE degradation efficiency were 22% and 27.2% higher than biological control without electric stimulation (BC), respectively. The extracellular polymeric substance (EPS) concentration in BES (39.38 mg L⁻¹) was higher than control (33.36 mg L⁻¹); moreover, the membrane permeability and ATPase activities were also enhanced and there existing phthalic acid and salicylic acid metabolic pathways in the strain. The degradation genes nahAc, pcaH, and xylE expression levels were upregulated by micro-electric stimulation. This is the first study to analyze the physiological and metabolic effect of micro-electric stimulation on a PHE-degrading strain in detail and systematically.
Показать больше [+] Меньше [-]Spatial econometric analysis of carbon emission intensity in Chinese provinces from the perspective of innovation-driven
2019
Liang, Song | Zhao, Jingfeng | He, Shumin | Xu, Qingqing | Ma, Xin
This study estimates the carbon emission intensity of China’s provinces during the period from 2000 to 2015. First, the temporal and spatial pattern evolution of China’s carbon emission intensity was analyzed using spatial statistics. Then, from an innovation-driven perspective, combining the data of innovative technologies and scale factors to construct a spatial panel model to explore the main influencing factors of carbon emission intensity and its spatial spillover effect. The results show that: China’s provincial carbon emission intensity has obvious spatial agglomeration characteristics, and regional differences are improving, and the spatial spillover effect of some influencing factors is obvious; innovation indicators such as the number of patent authorizations, technical market turnover, and foreign direct investment, and GDP have a significant negative impact on carbon intensity, and the effects of general scale variables such as urbanization rate, energy consumption, and population density on carbon intensity are significantly positive.
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