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The Measurement and Influencing Factors of Agricultural Carbon Emissions in China’s Western Taiwan Straits Economic Zone
2020
Yihui Chen , Minjie Li
Carbon emissions in agricultural production activities have become an important source of accelerating climate warming. At present, low-carbon agriculture is not only an important means to mitigate climate warming, but also a necessary process of transformation from traditional agriculture to modern agriculture. Therefore, to achieve the sustainable development of agriculture in China’s Western Taiwan Straits Economic Zone (WTS Economic Zone), the governments should vigorously promote the upgrading and realize the development of low-carbon agriculture. By adopting the latest emission coefficients and the ordered weighted averaging (OWA) aggregation operator, this paper selected agricultural land use, rice paddies, crop production, livestock manure storage and livestock enteric fermentation as the five carbon emission sources, and measured agricultural carbon emissions in the WTS Economic Zone from 2010 to 2017. Thus, from the time perspective, the average agricultural carbon emissions in the WTS Economic Zone showed a fluctuating downward trend, from 762.64 × 103 tonnes in 2010 to 710.02 × 103 tonnes in 2017. From the spatial perspective, total agricultural carbon emissions among regions are quite different. To further clarify the factors affecting agricultural carbon emissions in the WTS Economic Zone, by applying the geographically and temporally weighted regression (GTWR) model, this paper selected the research and development intensity, the added value of agriculture, the proportion of agricultural labour force, the overall level of urbanization, per capita disposable income of rural residents and per capita arable land areas as the influencing factors, and then measured the direction and degree of the influences on agricultural carbon emissions in different temporal-spatial backgrounds. The results showed that the added value of agriculture, the proportion of agricultural labour force and per capita arable land areas had positive influences on agricultural carbon emissions, while the research and development intensity, the overall level of urbanization and per capita disposable income of rural residents had negative impacts. Although agricultural carbon emissions in the WTS Economic Zone have decreased in recent years, further measures can be taken to effectively reduce agricultural carbon emissions, and ultimately promote the development of low carbon agriculture according to the results of this study.
显示更多 [+] 显示较少 [-]Hydrolithological Investigation for Near-Surface Aquifers Within Lekki Peninsula, Lagos, Southwestern Nigeria
2020
O. G. Bayowa, T. A. Adagunodo, O. A. Olaleye, A. E. Adeleke, M. R. Usikalu , S. A. Akinwumi
This study is aimed at investigating the near-surface aquifers within Lekki Peninsula, Lagos, Southwestern Nigeria. Thirty-one (31) Vertical Electrical Sounding (VES) data were acquired using the Schlumberger array with current electrode spacing, which varies between 1 and 400m. The VES data were quantitatively interpreted, and the final layer parameters obtained were used to generate 2D geoelectric sections. Litho-logs acquired within the Lekki Peninsula were used to correlate the geoelectric sections to understand the nature and depth of groundwater contained in each aquiferous zone. The lithologies delineated in the study area include the topsoil (fill and/or sand) with resistivity value, which varies between 39 and 1535Wm as well as layer thickness from 0.5 to 5.5m; second layer of wet clay/sandy clay (saturated with brackish water) with resistivity value, which varies between5 and 163Wm as well as layer thickness from 1.5 to 10m; third layer of clayey sand/sand (saturated with freshwater) with resistivity value, which varies between 10 and 898Wm as well as layer thickness value from5 to 34m; and fourth layer of clay (saturated with saline water) with resistivity value, which varies between 1 and 9Wm. Isolated sand bodies (probably unsaturated zone) with resistivity value, which varies from 648 to 3560 Wm, were delineated beneath VES stations 24, 25, 29 and 30. The study concludes that the topsoil (sand/fill), unsaturated zone (conglomerate), silty mud layer (brackish/ freshwater saturated), and sand layer (saline water-saturated) constitute the aquifers and water quality within Lekki Peninsular. The inhabitants of the study area are, therefore, advised to avoid absurd usage of water to reduce the pumping rate and intrusion into the saline water formation.
显示更多 [+] 显示较少 [-]Assessment of Trace and Rare Earth Element Levels in Stream Sediments in Ijero-Ekiti Area, Southwest Nigeria
2020
H. Y. Madukwe, O. A. Ibigbami , R. A. Obasi
The study considered the level, sources and extent of trace and rare earth elements (REE) contamination in Agbangudu stream sediments in Ekiti State, Southwestern Nigeria. The samples were analysed with Laser Ablation Inductively Coupled Plasma Spectrometer (LA-ICP-MS). The trace and rare earth elements’ concentration ranged from 0.50 (Mo) to 750 (Ba) and 0.16 (Lu) to 175 (Ce) ppm respectively. The results revealed that the sediments are not that enriched in REEs. The Pollution Load Index (PLI) indicates baseline levels of the metals. The geochemical index (Igeo) of the elements revealed uncontaminated to moderately contaminated, except for Cs and Ta with strongly to extremely contaminated status. The Average Shale Value (AVS) and the Upper Continental Crust (UCC) normalized REE distribution patterns of the sediments. To establish the relationship between the metals, Principal Component Analysis (PCA) and Clusters Analysis (CA) were used as classification techniques. Despite the common occurrences of the elements, their overall patterns were much different as revealed by the cluster analysis.
显示更多 [+] 显示较少 [-]Socio-Economic Utility of Coastal Flora Growing in and Around Mangrol Taluka (Junagadh) of Gujarat
2020
T. B. Chudasama and S. J. Vyas
Halophytes are widely distributed throughout several regions due to the presence of the saline condition. The present paper reflects vegetation cover along with plant species of different kinds in the coastal area of Mangrol taluka of Gujarat, India. It consists of 25 plant species under 25 genera and 12 families of angiosperm. During the field survey, observations were made and plant characteristics and habitat of flora were studied. The main objectives of the present study are the identification, baseline survey and utility of saline plants in the area. The utility of the plants such as ecological and economic (such as medicinal, industrial and commercial, etc.) which can reflect their significance to the society. Majority of the plant species found are naturally occurring, but a few of them are agricultural plants used for various purposes. Due to increasing population growth, urbanization and especially over-demanding medicinal plants people are harvesting without any knowledge of regeneration and conservation, due to which many species are threatened. Because of this, it is very important to conserve plant species, which are extensively utilized in various purposes.
显示更多 [+] 显示较少 [-]Study on the Efficiency of the Synchronous Alkali-ultrasonic Pretreatment of the Low Organic Matter Sludge and its Influence on the Microbial Population in the Anaerobic Digestion System
2020
Shihu Liu, Lei He, Pengcheng Zhao, Xuejie He, Xingxing Zhuo and Jian Zhou
To solve the problem of the low anaerobic digestion efficiency of the minimal organic matter sludge, the study proposes the synchronous alkali-ultrasonic pretreatment technology of the low organic sludge. The research results show that the collaboration between alkali and ultrasonic has significant effects on pretreatment efficiency. The pretreatment efficiency of the sorts is as follows: synchronous alkaliultrasonic treatment > alkali-ultrasonic stepwise treatment > ultrasonic-alkali stepwise treatment > ultrasonic treatment > alkali treatment. The synchronous alkali-ultrasonic treatment system has strong processing effectiveness. Compared with the control group (the raw sludge), the concentrations of the supernatant SCOD and VFAs of the low organic matter sludge after the pretreatment increases by 15.4 times and 59.64 times respectively, and the supernatant that is easily biodegradable organic matter increases by 19.1%. The gas production after alkali-ultrasonic synchronous pretreatment of the anaerobic digestion system of the sludge increases 58% higher than the control group (without pretreatment ). The results of the high-throughput sequencing of 16S rRNA in the anaerobic digestion system of the sludge, at the genus level, show that the dominant functional bacteria in the system mainly includes vadinHA17, Peptoclostridium, Peptostreptococcaceae, Tissierella, Syntrophomonas, Synergistaceae and Aminobacterium. The dominant functional bacteria genera in the systematic archaea group mainly include Methanosaeta (70.33%), Unclassified (2.74%), Methanosarcina (15.49%), Methanobacterium (5.31%), Methanospirillum (2.18%), ARC26 (1.04%), Methanobrevibacter (1.62%). The abundance of functional bacteria at the genus level was higher than that in the control group.
显示更多 [+] 显示较少 [-]Assessment of Health of River Ganga at Varanasi, India
2020
Sonali Saxena and Prabhat Kumar Singh
World across, there is an increasing concern about river health. In India, Ganga River Basin Management Plan (GRBMP) 2015 considered River Ganga as an ecological entity. This paper attempts to present a framework for river health assessment in India and discusses its applicability for River Ganga near Varanasi. In the proposed framework, the River Health Condition (RHC) is assessed through the calculation of River Health Index (RHI) on a 0-100 scale and categorized as Acceptable or Poor. RHI is calculated by using selected parameters/indices normalized on the 0-5 scale based on their critical and target values. River Health is presented through a coloured circumscribed pentagon each of whose side represents one of five indicator groups: i. Organo-electrolytic-bacterial qualities. ii. Nutrients, iii. Algae, iv. Macroinvertebrates, and v. Fish. Application of the proposed framework has been tested and explained using observed data for four seasons per year for two years from five locations of River Ganga near Varanasi. The colour of circumscribing pentagon reflects overall river health condition at a given location and each side of pentagon reflects health score concerningto one indicator group. The analyses indicate that the health of River Ganga near Varanasi is improving with time. The river health is found at its best level during Spring season and unstable during Post Monsoon period at most of the locations. The severely reduced RHI indicate “Overstressed” condition of River Ganga at the confluence points of River Assi and Varuna, which are evidenced by the presence of pollution tolerant biotic species. There are clear stretches of the river near outfall points which are nutrients rich and organically polluted causing poor health of river showing a disturbed balance of biotic species. Indicator group score based RHI gives a clear identification of critical parameters which may be used in strategic planning for river health restoration.
显示更多 [+] 显示较少 [-]Assessment of Heavy Metal Concentration in Tissues of Three Owl Species From Visakhapatnam, India
2020
Sanchari Biswas, Ch Ramakrishna and Y A Maruthi
The occurrence of heavy metals into the environment through various natural and anthropogenic sources is inevitable due to their persistent nature. This study investigated the concentration of heavy metals lead (Pb), zinc (Zn) and chromium (Cr) in liver, kidney, muscle and bones of three different species of owls namely Indian Eagle Owl (Bubo bengalensis), Barn Owl (Tyto alba) and Spotted Owlet (Athene brama) from Visakhapatnam, Andhra Pradesh, India. Given their sentinel role, birds can be used as suitable and reliable indicators in monitoring the quality of the environment. From the study, it was observed that Bubo bengalensis accumulated the highest concentration of metals followed by Athene brama and Tyto alba. On an average, the concentration of Zn (1.67±1.40 ?g/g) was higher than Pb (0.079±0.05 ?g/g) and Cr (0.99±1.11 ?g/g). Among all the species, Spotted Owlet (Athene brama) recorded the highest concentration of Zn in bone (3.98 ?g/g) whereas in the bone of Indian Eagle Owl (Bubo bengalensis) 2.44 ?g/g of chromium (Cr) was reported. Pearson’s correlation of the data showed significant positive correlations in the absorption of metals by the tissues. Kruskal-Wallis ANOVA was applied to validate the results and check whether the groups originated from the same population. Additionally, Principle Component Analysis (PCA) revealed that Pb showed a strong relationship with both Zn and Cr and might be due to the differences of sources of these elements in the environment.
显示更多 [+] 显示较少 [-]An Impact-Control Study to Assess the Potential Accumulation of Metals and Metalloids from Sewage Effluent and Biosolids to Sydney Rock Oysters, Saccostrea glomerata
2020
Andrew-Priestley, M. N. | O’Connor, W. A. | Dunstan, R. H. | MacFarlane, G. R.
Sewage effluent has been identified as a potential source of metal(loid) contamination in the aquatic environment. The Sydney rock oyster, Saccostrea glomerata, can accumulate most metals and is well established as a biomonitor of metals in the marine environment. To determine if Burwood Beach wastewater treatment works (WWTW) is a source of metal(loid) contamination, S. glomerata was deployed for 6 weeks in effluent receiving waters (Burwood Beach near and Burwood Beach far) and at reference locations (Redhead, Fingal Island 1 and Fingal Island 2) at depths 4, 8 and 12 m. In dried oyster tissue, inductively coupled plasma mass spectrometry (ICPMS) was employed to measure concentrations of a suite of metal(loid)s including aluminium, arsenic, cadmium, copper, lead, iron, manganese, mercury, nickel, selenium, silver and zinc. It was found that for all metal(loid)s, S. glomerata tissue concentrations were not significantly higher at Burwood Beach locations in comparison to all reference locations. Concentrations of metal(loid)s were similar to those which have been detected in previous studies of background locations in New South Wales (NSW). Further, all metals fell below National Food Authority maximum residue levels (MRLs), except for arsenic and this does not appear uncommon for concentrations in biota within NSW. Comparisons to historical data suggested that concentrations of metal(loid)s in sewage effluent from Burwood Beach WWTW, assessed via concentrations in oyster tissue, are similar or lower, suggesting that changes in treatment processes initiated in the intervening time have lowered metallic inputs.
显示更多 [+] 显示较少 [-]Earthworms to improve glyphosate degradation in biobeds
2020
Lescano, Maia R. | Masin, Carolina E. | Rodríguez, Alba R. | Godoy, José L. | Zalazar, Cristina S.
In this work, earthworm effect on the efficiency of biobeds for glyphosate degradation was studied. Three biomixtures with and without the addition of earthworms (Eisenia fetida species) were evaluated. The initial concentration of glyphosate was 1000 mg/kg biomixture. Glyphosate and biological parameters were measured as a function of time. Earthworm survival, biomass, and reproduction were evaluated as well. All biomixtures that contain earthworms reached 90% of glyphosate degradation at 90 days in comparison with the biomixtures without earthworms that reached 80% approximately at the same time. Also, within the biomixtures that contained earthworms, glyphosate degradation rate was significantly higher in the one made up with soil and wheat stubble (Ws-E) showing excellent capacity for aminomethylphosphonic acid (AMPA) degradation, the main metabolite of glyphosate degradation. In addition, a study performed after the vermiremediation process showed that E. fetida can tolerate high glyphosate concentration without modifications in its life traits. It can be concluded that the use of E. fetida within the biobeds is an excellent combination to improve glyphosate and AMPA removal.
显示更多 [+] 显示较少 [-]Microplastics in wastewater: microfiber emissions from common household laundry
2020
Galvão, Ana | Aleixo, Margarida | De Pablo, Hilda | Lopes, Clara | Raimundo, Joana
Microplastics are widely recognized as a category of emergent pollutants that can cause complex ecotoxicological effects. Synthetic fibers released during the washing of textiles are a relevant source of microplastics, which reach aquatic ecosystems from sewer discharges, even when there is retention in wastewater treatment plants. In this paper, we determined microfiber emissions from washing of textiles in a domestic environment, by collecting wastewater from washings of a mix of clothing from a household of 4 people. It is the first time the characterization of microplastic emission from textiles washing is performed in real household conditions. Results estimated an average emission rate of 18,000,000 synthetic microfibers for a reference load of 6 kg of synthetic fibers. Only 7% of the synthetic fibers found were larger than 500 μm in length, 40% were between 100 and 500 μm, and 53% were between 50 and 100 μm.
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