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Trace metal biomonitoring in the east Gippsland Lakes estuary using the barnacle Amphibalanus variegatus and mussel Mytilus edulis النص الكامل
2020
Willems, Daniel J | Reeves, Jessica M. | Morrison, Paul D. | Trestrail, Charlene | Nugegoda, Dayanthi
The Gippsland Lakes estuary, a Ramsar listed wetland, in Victoria, Australia, is an area of potential concern for metal pollution due to influxes of human population and associated anthropogenic activities. A biomonitoring exercise was undertaken where the concentrations of 9 metals (Cr, Fe, Cu, Zn, As, Se, Ag, Cd and Hg) were analysed in the soft tissue of two common sessile invertebrates: the mussel Mytilus edulis and the barnacle Amphibalanus variegatus from 6 locations on two different occasions throughout the Gippsland Lakes estuary. A salinity gradient exists in the Lakes, from seawater at Lakes Entrance in the east, decreasing down to < 10 PSU in the west at Lake Wellington during times of rainfall, which is a major factor governing the growth and distribution of both species. Dissolved metal levels in general were low; however, Cu at most sites exceeded the 90% trigger values, while all Zn concentrations exceeded the lowest 80% trigger values of the ANZECC marine water quality guidelines for environmental health. Elevated levels of Cu and Zn were found particularly in barnacles at some sites with environmental contamination due to leaching from anti fouling paints and sacrificial zinc anodes. Elevated levels of Ag and Cd were found in mussels at the Hollands Landing site, which is immediately adjacent to a boat ramp, and Cd and Ag at this site are suspected to originate from inland anthropogenic sources. Concentrations of As in M. edulis across all 6 sites in both sampling periods had mean wet weight As concentrations exceeding the maximum level stated in the FSANZ guidelines. A. variegatus contained elevated levels of Hg especially at the North Arm site with a maximum of 13.6 μg Hg/g dry wt., while A. variegatus also showed temporal changes in Hg concentrations across sites. The maximum Hg concentration found in Mytilus edulis was 1.49 μg Hg/g dry wt. at the Hollands Landing site. Previous contaminant studies of biota in the Lakes have targeted sampling of singular predatory or migratory species, such as Black Bream (Acanthopagrus butcheri) and the Burrunan dolphin (Tursiops australis). This is the first biomonitoring study conducted on sessile organisms to assess metal contamination in the system.
اظهر المزيد [+] اقل [-]Effective allocation of resources in water pollution treatment alternatives: a multi-stage gray group decision-making method based on hesitant fuzzy linguistic term sets النص الكامل
2020
Wang, Jue | Qian, Wuyong | Du, Junliang | Liu, Yong
With the significant economic shift, water pollution treatment has gradually become a key problem which needs to be deeply investigated for the sustainable development of China. In the face of specific water pollution incidents, multiple alternatives are often required to work together in order to achieve better results. However, due to the limitation of resources, alternatives must be ranked to realize the effective allocation of resources, which means the more highly ranked ones should possess more disposable resources. Furthermore, the water pollution treatment process is a multi-stage and multi-objective process. In each stage, decision-makers may have different emphasis and thus have different preferences for the treatment alternatives. How to effectively aggregate decision-makers’ preferences in different stages into an overall preference so as to form a ranking of treatment alternatives under global constraints has turned into a problem worthy of discussion. Under such background, this paper proposes a multi-stage gray group decision-making method, where decision-makers use Group-G1 to rank and weight the criteria, and in this way, the weights of decision-makers and criteria in each stage could be determined. Considering the difference and deficiency of the cognitive level of decision-makers, this paper adopts the form of hesitant fuzzy linguistic term sets (HFITS) to express the evaluation information of decision-makers. And then, gray incidence analysis is selected to rank the alternatives. After ranking the alternatives in each stage, the multi-stage rankings will be aggregated into an overall ranking and the resource allocation is made according to the priorities of the alternatives. Finally, an example of water pollution treatment alternatives ranking based on a cyanobacterial bloom in Taihu Lake, China, is given to illustrate the proposed approach.
اظهر المزيد [+] اقل [-]Synergistic effect of heartwood extracts in combination with linseed oil as wood preservatives against subterranean termite Heterotermes indicola (Blattodea: Rhinotermitidae) النص الكامل
2020
Hassan, Babar | Aḥmad, Suhail | Kirker, Grant | Mankowski, Mark E. | Misbah ul Haq, Muhammad
This study evaluated the effect of wood extracts from Tectona grandis, Dalbergia sissoo, Cedrus deodara, and Pinus roxburghii combined with linseed oil as protectants of two non-durable wood species against the termite, Heterotermes indicola. Heartwood blocks (19 × 19 × 19 mm) and wood shavings were extracted using an ethanol/toluene (2:1) solvent system. Results of choice and no-choice tests with solvent-extracted and non-extracted heartwood blocks showed greater wood mass loss from termite feeding on solvent-extracted blocks compared with non-extracted blocks for all wood species. Significantly higher termite mortality was observed after termite exposure to non-extracted blocks compared with extracted blocks for all durable species. Sapwood blocks of two non-durable wood species (southern pine and cottonwood) were vacuum/pressure impregnated separately with each of the four types of extract at a concentration of 7.5 mg ml⁻¹, linseed oil (20%) and a mixture of oil (20%) and extracts (4.25 mg ml⁻¹) for the laboratory and field tests. Results showed that extract-oil mixture imparted significantly higher termite resistance compared with linseed or extracts alone under laboratory conditions. This apparent synergistic effect was clearly noted when linseed oil was combined with extracts from T. grandis or D. sissoo followed by an extract-oil mixture using C. deodara. These extract oil mixtures showed significantly less weight loss for the treated non-durable wood species and higher termite mortality (83–100%) compared with the control treatments and other extract-linseed oil mixtures tested. Treatment of both non-durable wood species with T. grandis + oil and D. sissoo + oil prevented termite damage compared with other treatments when blocks and stakes were exposed in the field for a period of 2 years. Results of the current study indicated that a mixture of a particular heartwood extract with linseed oil has potential to be used as environmentally friendly wood protectants.
اظهر المزيد [+] اقل [-]Saussurea lappa root extract ameliorates the hazards effect of thorium induced oxidative stress and neuroendocrine alterations in adult male rats النص الكامل
2020
Abdel-Rahman, Mona | Rezk, Mohamed M. | Ahmed-Farid, Omar A. | Essam, Safia | Abdel Moneim, Ahmed E.
The present study was aimed to estimating the effect of Saussurea lappa (costus) root extract on thorium accumulation in different brain regions (cerebral cortex, cerebellum, and hypothalamus) of adult male albino rats and also to evaluate the antioxidant effect and thyroid gland modulation activity of costus following thorium toxicity. Adult male rats were randomly allocated into four groups; control group receiving saline (0.9% NaCl), thorium group receiving an intraperitoneal (i.p.) injection of thorium nitrate (Th; 6.3 mg/kg bwt), costus group receiving an oral administration of costus extract at 200 mg/kg bwt and costus + thorium group receiving costus 1 h before thorium injection. Thorium injection in rats for 28 days resulted in the accumulation of Th maximally in the cerebellum followed by the cerebral cortex and then in the hypothalamus. The accumulation of Th was associated with significant disturbance in sodium and potassium ions. A significant decrease in monoamines was also observed in different brain regions. Furthermore, the results indicated that Th-induced oxidative stress evidenced by increased lipid peroxidation and nitric oxide and decrease the glutathione content. Additionally, Th caused a significant increase in thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) levels in the serum of rats. However, the pre-administration of costus alleviated all of those disturbances. Our results revealed that costus extract exerted its protective effect mainly through potentiating the antioxidant defense system.
اظهر المزيد [+] اقل [-]Assessment of mining activities on tree species and diversity in hilltop mining areas using Hyperion and Landsat data النص الكامل
2020
Kayet, Narayan | Pathak, Khanindra | Chakrabarty, Abhisek | Kumar, Subodh | Singh, Chandra Prakash | Chowdary, Vemuri Muthayya
The tree species and its diversity are two critical components to be monitored for sustainable management of forest as well as biodiversity conservation. In the present study, we have classified the tree species and estimated its diversity based on hyperspectral remote sensing data at a fine scale level in the Saranda forest. This area is situated near the mining fields and has a dense forest cover around it. The forest surrounding the study area is exhibiting high-stress condition as evidenced by the dying and dry plant material, consequently affecting tree species and its diversity. The preprocessing of 242 Hyperion (hyperspectral) spectral wavebands resulted in 145 corrected spectral wavebands. The 21 spectral wavebands were selected through discrimination analysis (Walk’s Lambda test) for tree species analysis. The SVM (support vector machine), SAM (spectral angle mapper), and MD (minimum distance) algorithms were applied for tree species classification based on ground spectral data obtained from the spectroradiometer. We have identified six local tree species in the study area at the spatial level. The result shows that Sal and Teak tree species are located in the upper and lower hilly sides of two mines (Meghahatuburu and Kiriburu). We have also used hyperspectral narrow banded vegetation indices (VIs) for species diversity estimation based on the field-measured Shannon diversity index. The statistical result shows that NDVI705 (red edge normalized difference vegetation index) is having the best R² (0.76) and lowest RMSE (0.04) for species diversity estimation. That is why we have used NDVI705 for species diversity estimation. The result shows that higher species diversity values are located in the upper and lower hilly sides of two mines. The linear regression between Hyperion and field measured Shannon index shows the R² (0.72) and RMSE (0.15). This study will aid in effective geoenvironmental planning and management of forest in the hilltop mining areas.
اظهر المزيد [+] اقل [-]Development and validation of a photobioreactor for uniform distribution of light intensity along the optical path based on numerical simulation النص الكامل
2020
Yan, Zhi-Jiao | Liu, Jing | Qian, Lei | Xu, Wen-Lai | Yuan, Zhen | Zhao, Chen-Xi
A theoretical approach was followed to optimize the design of a cylindrical photobioreactor for wastewater treatment based on algal culture. In particular, the problem of uneven light distribution that impairs algal growth was minimized by optimizing the area of uniform illumination distribution for a bioreactor design that can be enlarged without affecting its performance. The theoretical analysis was based on modeled simulations to determine the best configuration and illumination mode. The Monte Carlo method was used to simulate the illumination distribution inside the bioreactor, and the relationships between the width of the area with uniform illumination and related parameters were explored. Based on these theoretical considerations and predictions, an actual experimental photobioreactor was built containing a working area (where culture of Chlorella pyrenoidosa was enabled) and a catchment area for effluent. The performance of this bioreactor was tested with synthetic wastewater as a substrate. The light distribution was found to be relatively uniform inside the bioreactor, supporting excellent algal growth and resulting in maximum removal rates of 84.41% for total nitrogen, 99.73% for total phosphorus, 85.03% for NH₄⁺-N, and 75.94% for chemical oxygen demand (COD) over a period of 32 days of operation. The presented approach provides new insights for improving the efficiency and scalability of photobioreactors and promotes their development for wastewater treatment and resource utilization.
اظهر المزيد [+] اقل [-]Copper carboxymethyl cellulose nanoparticles for efficient removal of tetracycline antibiotics in water النص الكامل
2020
ALOthman, Zeid A. | Badjah, Ahmad Yacine | Alharbi, Omar M. L. | Ali, Imran
Copper carboxymethyl cellulose nanoparticles were prepared and characterized by FT-IR, XRD, SEM, TEM, and EDX techniques. Removal of tetracycline was obtained at 90% with optimized parameters of 500 μg/L concentration, 40 min contact time, 7.5 pH, 1.5 g/L dose, and 298 K temp. The adsorption followed Freundlich model very well in comparison to Langmuir. Tempkin model described good interactions between tetracycline and nanoparticles. Dubinin–Radushkevich isotherm confirmed the chemical nature of adsorption. The adsorption was pseudo-second order with a liquid film diffusion kinetics mechanism. The adsorption was endothermic and spontaneous as suggested by thermodynamics results. The supramolecular mechanism was developed for the process. Interestingly, the process was suitable at 7.5 pH with low contact time. These features of the adsorption made this process applicable at natural water conditions, making the process eco-friendly and feasible. Therefore, it may be an excellent method for the removal of tetracycline in any water system.
اظهر المزيد [+] اقل [-]Prediction of voltage required for nonthermal plasma based diesel exhaust treatment for removal of nitrogen oxides النص الكامل
2020
Allamsetty, Srikanth | Mohapatro, Sankarsan | Kumar, Pushpendra
A prior prediction of voltage required for the nonthermal plasma (NTP)-based diesel exhaust treatment toward removal of nitrogen oxides, i.e., NOX (sum of NO and NO₂) would help the researchers to plan for the resources required for the treatment. In this present study, experimental data set of 4032 number of input-output pairs have been collected by taking flow rate (Fr), temperature (T), discharge gap (Dg), initial NOX concentration (NOXᵢ), and NOX removal efficiency (ηᵣ) as the 5 inputs and the voltage required for the treatment (Vᵣₜ) as the output. Then, an attempt has been made to predict Vᵣₜ for achieving particular ηᵣ, while other input parameters have fixed values, using multivariable linear and quadratic polynomial regression techniques. The performances of these two predictive models have been assessed during training and testing. The root mean square error (RMSE) between experimental and predicted values of Vᵣₜ with both the models has been compared, where quadratic polynomial regression-based model has been found to be performing well with an RMSE of 0.85 kV for a test data of 1210 sets. This study shows that the voltage required for the treatment, to achieve a particular amount of NOX removal from the exhaust, can be predicted with very good accuracy so that the necessary arrangements for the treatment can be made by the researchers.
اظهر المزيد [+] اقل [-]ZnO nanoparticles-induced oxidative stress in Chenopodium murale L, Zn uptake, and accumulation under hydroponic culture النص الكامل
2020
Zoufan, Parzhak | Baroonian, Maryam | Zargar, Behrooz
To understand toxic effect of Zn oxide nanoparticles (ZnO NPs) on Chenopodium murale, 40-day-old plants were exposed to 10, 50, and 250 mg L⁻¹ of NPs using hydroponic system under controlled light and temperature conditions. Aboveground parts and roots were harvested 3 and 6 days after treatments and evaluated for some growth and biochemical indices. By increasing the concentration of ZnO NPs, the content of Zn increased in the roots more than the shoots. Our findings showed that all ZnO NPs treatments resulted in a decrease in growth, total chlorophyll content and soluble proteins, while the content of carotenoids, lipid peroxidation, leaf hydrogen peroxide (H₂O₂), and leaf electrolyte leakage increased significantly compared with the control. These changes, along with increased proline content and catalase (CAT), guaiacol peroxidase (GPX), and superoxide dismutase (SOD) activities in the treated plants, suggest that all concentrations of ZnO NPs used in this study strongly induced oxidative stress. A decline in growth-related indicators can be considered as an indicator of ZnO NPs phytoxicity in C. murale. Based on the concentration of Zn dissolved in the solution, the effects of Zn released into the nutrient solution may be greatly involved in induction of toxicity and retardation of growth at least under our experimental conditions. The results of this study suggest that an important mechanism of ZnO NPs phytotoxicity may be the exacerbation of oxidative stress and damage to biomembranes.
اظهر المزيد [+] اقل [-]Pollution characteristics, sources, and health risk assessments of urban road dust in Kuala Lumpur City النص الكامل
2020
Othman, Murnira | Latif, Mohd Talib
Urban road dust contains anthropogenic components at toxic concentrations which can be hazardous to human health. A total of 36 road dust samples from five different urban areas, a commercial (CM), a high traffic (HT), a park (GR), a rail station (LRT), and a residential area (RD), were collected in Kuala Lumpur City followed by investigation into compositions, sources, and human health risks. The concentrations of trace metals in road dust and the bioaccessible fraction were determined using inductively couple plasma-mass spectrometry (ICP-MS) while ion concentrations were determined using ion chromatography (IC). The trace metal concentrations were dominated by Fe and Al with contributions of 53% and 21% to the total trace metal and ion concentrations in road dust. Another dominant metal was Zn while the dominant ion was Ca²⁺ with average concentrations of 314 ± 190 μg g⁻¹ and 3470 ± 1693 μg g⁻¹, respectively. The most bioaccessible fraction was Zn followed by the sequence Sr > Cd > Cr > Cu > Ni > Co > Mn > As > V > Pb > Fe > Al > U. The results revealed that the highest trace metal and ion concentrations in road dust and in the bioaccessible fraction were found at the LRT area. Based on the source apportionment analysis, the major source of road dust was vehicle emissions/traffic activity (47%), and for the bioaccessible fraction, the major source was soil dust (50%). For the health risk assessments, hazard quotient (HQ) and cancer risk (CR) values for each element were < 1 and in the tolerable range (1.0E-06 to 1.0E-04), except for As for the ingestion pathway. This result suggests a low risk from non-carcinogenic and probable risk from carcinogenic elements, with higher health risks for children compared to adults.
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