细化搜索
结果 3821-3830 的 4,937
Exploring ecosystem services and scenario simulation in the headwaters of Qiantang River watershed of China 全文
2019
Sun, Xiaoping | Zhang, Yinlong | Shen, Yu | Randhir, Timothy O. | Cao, Mingchang
BACKGROUND: Land use change has a significant impact on ecosystem services in watershed systems. The upper part of Qiantang River, Kaihua Country has experienced land-use changes over the past 15 years, but the effect of these changes on ecosystem services remains unknown. OBJECTIVE: This study evaluates land-use changes in response to ecological protection and the effects on ecosystem services. METHODS: Ecosystem services during 2000–2015 are assessed and compared to future land use scenarios in 2025 (business-as-usual, strategic planning, environmental protection, and economic development). These scenarios are identified in collaboration with local stakeholders and used to assess changes in ecosystem services under future scenarios. RESULTS: Analysis shows that during 2000–2015, the woodland increased by 7335 ha as a result of the “Grain for green” policy, and the built-up land increased by 2259 ha due to urbanization, and these changes affected ecosystem services, such as water yield, nitrogen and phosphorus exports which decreased by 0.29%, 12.45%, and 13.74%, respectively, and soil retention, carbon storage, and habitat quality index increased by 0.05%, 1.36%, and 0.80%, respectively. CONCLUSION: Among all the future scenarios, the strategic planning scenario is an optimal land use strategy to balance the demand for urban development, while providing higher levels of ecosystem services.
显示更多 [+] 显示较少 [-]Environmental concentration of fluoxetine disturbs larvae behavior and increases the defense response at molecular level in zebrafish (Danio rerio) 全文
2019
Parolini, Marco | Ghilardi, Anna | De Felice, Beatrice | Del Giacco, Luca
Fluoxetine (FLX) is one of the main antidepressants used worldwide. After human use, FLX enters the aquatic ecosystems, where it has commonly detected in the high ng/L concentration range. Several investigations have shown that exposure to different concentrations of FLX caused different adverse effects towards a number of aquatic species. However, the information on the onset and the relationship between molecular and behavioral FLX-induced effects remains scant. The aim of this study was to assess the effects induced by two FLX concentrations, namely 50 ng/L and 500 ng/L, on swimming activity of zebrafish (Danio rerio) larvae at 96-h post-fertilization (hpf) and to investigate if such behavioral effects were related to modulation of the expression of oxidative stress-related (sod1, sod2, cat, gpxa, and gst), stress- and anxiety-related (oxtl, prl2, npy, and ucn3l) genes, and genes encoding for the transporters of the main neurotransmitters (slc6a3, slc6a4a, slc6a4b, slc6a11). Fluoxetine exposure altered the swimming behavior of larvae, as shown by the reduction of the distance traveled by treated larvae in response to an external stimulus. Such behavioral change was related, at molecular level, to an enhanced expression of sod1, cat, and gpxa, suggesting an overproduction of pro-oxidant molecules. In addition, FLX modulated the expression of oxtl, slc6a4a, slc6a4b, and slc6a11, suggesting its capability to affect anxiety- and neurotransmitter-related genes.
显示更多 [+] 显示较少 [-]Aquatic geochemistry status in the south, central, and highland regions of Vietnam 全文
2019
Cuong, Le Phuoc | Van Tho, Luong | Juzsakova, Tatjana
Aquatic geochemical distribution in the Central, Highland, and Southern regions of Vietnam, including: Da Nang city (Hoa Khanh Industrial Park, Aquaculture Industrial Zone Tho Quang, Do Toa River Deposit Area), Da Lat city (Prenn Pass), Dong Nai province (Suoi Ram hamlet, Cam My district, Long Giao) was investigated by using 2D electrical resistivity tomography (ERT) combined with geochemical analysis. In this research, the correlation between tectonic formation, geochemical composition, and groundwater distribution was assessed between regions. Geochemistry of the Holocene aquifer (from 10 to 30 m underground) was studied considering major ions and trace elements measured in wet and dry seasons. The results of chemometric evaluation show that groundwater in Central Vietnam, Da Nang in particular, has a higher frequency of environmental toxin distribution than in Da Lat and Dong Nai. Groundwater in Da Lat with the advantage of high distribution of K, Ca, Mg, Fe, and Zn. The micro and macro elements such as Co, Mo, Na have high distribution in groundwater in Dong Nai. Meanwhile, groundwater at the study sites in Da Nang showed high concentrations of heavy metals with high toxicity such as, Al, Pb, and Ni. In Da Nang city, the concentration of Pb in groundwater samples from Holocene aquifer ranges between 74 in dry season and 214 ppb in wet season, exceeding the WHO guideline of 21 ppb. There is an increase of mean temperature of groundwater from Holocene aquifer of studied areas, from 17 in wet season to 26.2 °C in dry season. It shows that the ambient temperature effects on the groundwater reflects the relatively surficial character of Holocene aquifer. At the same time, the impact factors, including natural conditions, production methods, customs, and habits were analyzed to formulate the risks and potential risks of geohazards in mechanical construction, infrastructure, civil works, and underground works affecting the social security in the research areas. Through the convection and transfer processes, the electrolyte pollutants such as NaCl, KCl, and acetic acid (the resistivity is about 5.38 Ω m) have been accumulated in groundwater of Da Nang — a developing city with industrial clusters. This problem is similar to Suoi Ram hamlet, where groundwater is also showing signs of pollution due to the use of chemicals in cultivation (mainly cashew nut growth). In terms of density and flow of underground water, according to the results of the electrical images, generally in Suoi Ram Hamlet pollution is much larger than the Hoa Khanh industrial park (Da Nang), which is also quite reasonable because the southern area is lower than the Central and Highland regions. Research contributed importantly in finding the rules of geological distribution, groundwater at elevation topography, of great significance in the earth and environmental science.
显示更多 [+] 显示较少 [-]Influence of CaO-activated silicon-based slag amendment on the growth and heavy metal uptake of vetiver grass (Vetiveria zizanioides) grown in multi-metal-contaminated soils 全文
2019
Mu, Jing | Hu, Zhengyi | Xie, Zijian | Huang, Lijuan | Holm, Peter E.
Few plant species used for revegetation grow well in multi-metal-contaminated soils. Vetiver grass (Vetiveria zizanioides) is known to be tolerant of heavy metals. Vetiver has been reported to be effective for revegetation and heavy metal phytoextraction by applying targeted amendments due to its large biomass. In this study, a greenhouse vetiver pot experiment and soil incubation were performed to investigate the growth and Cd, Cr, Cu, Pb, and Zn uptake of vetiver grown in multi-metal-contaminated soils treated with a CaO-activated Si-based slag amendment (0, 0.5, 1.0, and 2.0% w/w). The results showed that the effects of slag amendment on plant growth and heavy metal uptake and distribution were dependent on the amendment dosages and metal species. Although vetiver could grow in contaminated soils, its growth was obviously inhibited. The slag amendment enhanced the vetiver growth and the highest biomass (2.62-fold over the control) was determined at a 1.0% amendment rate. The slag amendment improved plant growth by alleviating the toxicity of heavy metals in plants. This result was mainly attributed to the increases in soil pH and citric acid-extractable Si caused by alkaline amendment. The results suggest that vetiver can be applied to remediate multi-metal-contaminated soils in conjunction with the application of CaO-activated Si-based slag amendment.
显示更多 [+] 显示较少 [-]Antioxidant enzyme activity in responses to environmentally induced oxidative stress in the 5th instar nymphs of Aiolopus thalassinus (Orthoptera: Acrididae) 全文
2019
Yousef, Hesham A. | Abdelfattah, Eman A. | Augustyniak, Maria
The response of antioxidant enzymes to oxidative environmental stress was determined in 5th instar nymphs of Aiolopus thalassinus (Orthoptera: Acrididae) collected from sites with different level of pollution with heavy metals, PO₄³⁻, and SO₄²⁻. The high polluted site induced higher DNA damage to individuals compared to the control site. The highest values of tail length (TL), tail moment (TM), and percent of DNA in tail (TDNA) were found in the gut of 5th instar nymphs from a high polluted site. Also, protein carbonyls and lipid peroxide levels were significantly higher in insects collected from polluted sites compared to those from the control site. A strong positive correlation between both protein carbonyl and lipid peroxide concentration and the pollution level of the sites was found in all tissues of the insects. The activity of superoxide dismutase (SOD) in the brain of insects collected from the high polluted site was significantly higher than that in the thoracic muscles and gut. We observed strong inhibition of catalase (CAT) activity. This effect was apparently caused by pollutants present at the high polluted site. The level of pollution significantly influenced polyphenol oxidase (PPO) activity in A. thalassinus nymphs in all examined tissues. The highest values were observed in the brain. The relationship between pollution and ascorbate peroxidase (APOX) activity in the examined tissues had no clear tendency. However, the lowest APOX activity was observed in individuals from the low polluted site. Level of pollution of sampling sites, oxidative stress biomarkers, and enzymatic response in A. thalanthsis 5th instar were negatively or positively correlated. Oxidative damage parameters, especially the percent of severed cells, lipid peroxides, and the activity of APOX, can be perceived as good markers of environmental multistress.
显示更多 [+] 显示较少 [-]Enhanced effects of ash and slag on SO3 formation in the post-flame region 全文
2019
Xiao, Haiping | Cheng, Qiyong | Li, Jian | Ge, Jinlin
The effects of slag, fly ash (formed in boiler above 1500 °C), and experimental ash (formed in muffle furnace at 815 °C) on the formation of sulfur trioxide (SO₃) were studied in a fixed bed rector. The results showed that the slag had the best catalytic effect on SO₃ formation, the effect of fly ash was second, and the effect of experimental ash was the worst. The reason may be that the forms of iron in different samples were different. Iron in the experimental ash all existed in the form of Fe₂O₃. Iron in the fly ash mainly existed in the form of composite iron oxides, such as Fe₀.₃Mg₀.₇SiO₃, Ca₃Fe₂(SiO₄)₃, and MgFe₂O₄. Iron in the slag also mainly existed in the form of composite iron oxides, such as CaFe₂O₄, MgFe₂O₄, and CaMgO₀.₈₈Fe₀.₁₂SiO₄. The different forms of iron had different effects on SO₃ formation. Composite iron oxides could produce more oxygen vacancies owing to lattice defects. This likely promoted the migration and regeneration of lattice oxygen and thus better promoted the formation of SO₃ than Fe₂O₃. Moreover, MgFe₂O₄ and Ca₃Fe₂(SiO₄)₃ could better promote SO₃ formation than CaMgO₀.₈₈Fe₀.₁₂SiO₄ and Fe₀.₃Mg₀.₇SiO₃. In addition, increasing the SO₂ concentration and O₂ concentration increased the SO₃ concentration but increasing the SO₂ concentration decreased the SO₃ formation ratio.
显示更多 [+] 显示较少 [-]Monitoring of airborne asbestos fibers in an urban ambient air of Shahryar City, Iran: levels, spatial distribution, seasonal variations, and health risk assessment 全文
2019
Taghizadeh, Farhad | Jafari, Ahmad Jonidi | Gholami, Mitra | Kermani, Majid | Arfaeinia, Hossein | Mohammadi, Saeid | Dowlati, Mohsen | Shahsavani, Abbas
Asbestos, as with other pollutants in the air, has adverse effects on the health of human beings and animals. Today, the relationship between presence of asbestos fibers in the air breathed by humans and developing serious diseases such as lung cancer (asbestosis) and mesothelioma has been proven. This study was designed and conducted within the time period of August 2017 and June 2018 to determine the concentration of asbestos fiber in the ambient air of Shahryar City and to evaluate their health effects for the general population of the city. For this purpose, samples were taken from four points, and overall 32 air samples were taken along the year. The samples were then analyzed by the phase contrast microscopy (PCM) method. Also, to investigate the type of asbestos and for more accurate counting of fibers, SEM analysis was utilized. Finally, based on the EPA IRIS method, the health effects resulting from asbestos risks were also evaluated. The results of this study indicated that the mean annual concentration of asbestos fiber in the ambient air of Shahryar City was obtained as 0.0019 f/ml PCM and 0.0072 f/ml SEM. Furthermore, the most polluted point was S1 point (0.0119 –0.0026 f/ml, PCM), while the lowest concentration was related to S4 point (0.001 f/ml PCM–0.0021 f/ml SEM). The mean annual risk resulting from airborne asbestos fiber in the ambient air of Shahryar City for all samples was obtained as 1.72 × 10⁻⁶ to 2.2 × 10⁻⁴, which was higher than the recommended risk range in some points.
显示更多 [+] 显示较少 [-]Quantitative and semi-quantitative risk assessment of occupational exposure to lead among electrical solderers in Neyshabur, Iran 全文
2019
Mohammadyan, Mahmoud | Moosazadeh, Mahmood | Khanjani, Narges | Rahimi Moghadam, Somayeh
Lead is one of the most widely used elements in the world. Lead can cause acute and chronic complications such as abnormal hemoglobin synthesis, kidney damage, abortion, nervous system disorders, male infertility, loss of learning ability, behavioral disorders, and even death. The aim of this study was to carry out quantitative and semi-quantitative risk assessments of exposure to lead among the solderers of the Neyshabur electronics industry. This cross-sectional, descriptive, and analytical study was conducted in 2017 and 2018 on 40 female soldering workers exposed to lead. Semi-quantitative risk assessment was carried out according to the Singapore Health Department and quantitative risk assessment according to the Office of Environmental Health Hazard Assessment (OEHHA) method. The average occupational exposure to lead in the electronics manufacturing industry was 93.89 ± 33.40 μg m⁻³ with a range from 9 to 150 μg m⁻³. Occupational exposure to lead in the industrial groups of initial soldering with an average of 130.37 ± 40.23 μg m⁻³ and cutting wires, electroplating, and coating bare parts with an average of 110.24 ± 30.11 μg m⁻³ was higher than the secondary soldering groups with an average of 90.78 ± 20.22 and shift supervisors with an average of 43.86 ± 10.97 μg m⁻³. The mean excess lifetime cancer risk (ELCR) was 0.11 per 1000 people and the mean non-carcinogenic risk (HQ) was 7.20. The results of this study indicate that there is a risk of non-carcinogenic complications among electronic solderers. Therefore, managers and employers should reduce lead exposure through engineering controls (substituting lead-free alloys, efficient ventilation) and management strategies such as reducing exposure hours.
显示更多 [+] 显示较少 [-]Choline, not folate, can attenuate the teratogenic effects ofdibutyl phthalate (DBP) during early chick embryo development 全文
2019
Wang, Rui | Sun, Da-Guang | Song, Ge | Guan, Chun Yi | Cui, Yi | Ma, Xu | Xia, Hong-Fei
Dibutyl phthalate (DBP), a persistent environmental pollutant, can induce neural tube abnormal development in animals. The possible effects of DBP exposure on human neural tube defects (NTDs) remain elusive. In this study, the distribution of DBP in the body fluid of human NTDs was detected by GC-MS. Then, chick embryos were used to investigate the effects of DBP on early embryonic development. Oxidative stress indicators in chick embryos and the body fluid of human NTDs were detected by ELISA. The cell apoptosis and total reactive oxygen species (ROS) level in chick embryos were detected by whole-mount TUNEL and oxidized DCFDA, respectively. The study found that the detection ratio of positive DBP and its metabolites in maternal urine was higher in the NTD population than that in normal controls. 8-hydroxy-2 deoxyguanosine (8-OHDG) and malondialdehyde (MDA) were evidently upregulated and superoxide dismutase (SOD) was observably downregulated in amniotic fluid and urine. Animal experiments indicated that DBP treatment induced developmental toxicity in chick embryos by enhancing the levels of oxidative stress and cell apoptosis. MDA was increased and SOD was decreased in DBP-treated embryos. Interestingly, the supplement of high-dose choline (100 μg/μL), not folic acid, could partially restore the teratogenic effects of DBP. Our data collectively suggest that the incidence of NTDs is closely associated with DBP exposure. This study may provide new insight for NTD prevention.
显示更多 [+] 显示较少 [-]Technoeconomic modelling and environmental assessment of a modern PEMFC CHP system: a case study of an eco-house at University of Nottingham 全文
2019
Sui, Sheng | Rasheed, Rizwan | Li, Qinglin | Su, Yuehong | Riffat, Saffa
This simulation study is aimed to model a contemporary Proton Exchange Membrane fuel cell (PEMFC) CHP system having a ‘heat and power’ autonomy as well as a provision of demand-driven electrical supply to the grid. A novel nanowire-electrode PEMFC stack is adopted within this PEMFC CHP system so to effectively replace the existing natural gas fuelled durable solid oxide fuel cell (SOFC) CHP system installed at David Wilson Millennium Eco-house at University of Nottingham. The energy savings, environmental, and economic performances of the proposed PEMFC system are determined and compared to the base case (SOFC) which is operated continuously to maintain a 1.5 kWe. While to meetup the highly fluctuating and seasonal demands of heating and power like in the UK, a PEMFC is more productive and advantageous over a SOFC. The proposed PEMFC unlike to the SOFC will be able to operate and adjust its output and turn down instantly as per changing conditions of ambient temperatures and loads in terms of electricity and heat. The results of the modelling predicted that as compared to the base case scenario, this PEMFC CHP system will efficiently reduce an annual CO₂ emission by 65.99% and fiscal costs by 66.74% with a viable internal rate of return as 8.93% and benefit to cost ratio as 1.02.
显示更多 [+] 显示较少 [-]