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Chemical Stabilization of Some Heavy Metals in an Artificially Multi-Elements Contaminated Soil, Using Rice Husk Biochar and Coal Fly Ash
2018
Saffari, M.
A greenhouse experiment has been planned for this study to delineate the benefits of two types of rice husk biochars (namely B300 and B600 which are prepared at 300°C and 600°C, respectvely) and coal fly ash (CFA), as soil amendments, for decreasing the amount of some heavy metals (like Pb, Cd, Ni, Cr, and Cu) as well as mobility and phytoavailability in an artificially-calcareous multi-element-contaminated soil. The effect of soil amendment on heavy metals’ availability has been evaluated via sequential extraction experiment and phytoavailability of the plant. According to the results, among the studied amendments, B600 has had the highest positive effect on both dry matter yield in corn and heavy metals’ availability reduction in post-harvest soil samples (with the exception of Cr), compared to CFA and B300, due to the increasing specific surface area, CEC, and pH that promote heavy metals’ sorption in the soil through surface complexation and ion exchange mechanisms. Evaluation of heavy metals’ chemical forms in post-harvest soil samples indicates that addition of amendments has significantly decreased mobility factor of heavy metals (with the exception of Cr in CFA-amended soils). In general, application of three soil amendments to this polluted soil has considerable effect on the reduction of heavy metals’ availability and phytoavailability. However, among the studied amendments, B600 and CFA have had the maximum and minimum effect on heavy metals’ availability reduction, respectively.
显示更多 [+] 显示较少 [-]Impact of Environmental Quality Variables and Socio-Economic Factors on Human Health: Empirical Evidence from China
2018
Ahmad, M. | Ur Rahman, Z. | Hong, L. | Khan, S. | Khan, Z. | Naeem Khan, M.
Carbon dioxide (CO2) is the foremost gas, emanated from human activities, and the best-known greenhouse gas, contributing to global warming, thus its negative effect on human health cannot be disregarded. The current paper investigates the relation between environmental quality variables, socio-economic factors, and human health from 1960 to 2014 in China, using Auto Regressive Distribution Lag (ARDL) Model. It selects three main environmental quality indicators (carbon emissions from coal, natural gas, and petrol) along with two representative socio-economic factors variables (per capita income and urban population) to explain the interaction mechanism. The results validate the long-term negative equilibrium impact of carbon emissions from the consumption of natural gas, coal, and petroleum on human health. The findings also reveal that migration from the countryside to cities and increase in per capita income improve quality of health. It is suggested that lowering emission of Carbon dioxide (CO2), which is the principal cause of greenhouse gas emissions, should be important in setting up the high quality of life for citizens.
显示更多 [+] 显示较少 [-]Effects of Cadmium and Dimethoate on Some Biological and Biochemical Indices in Freshwater Green Algae, Spirogyra sp.
2018
Banaee, M. | Taheri, S. | Hedayatzadeh, F.
The present study investigates the influence of an organophosphorus pesticide, namely Dimethoate, and cadmium on biomarkers of the green alga, Spirogyra sp., in a 14-day experiment. For so doing, it has exposed Spirogyra sp. to 0.0, 100, 200, and 400 mg L-1 of Dimethoate and/or 1 mg L-1 of cadmium chloride (CdCl2) to observe a reduction in chlorophyll a and b level in Spirogyra sp., exposed to 200 and 400 mg L-1 of Dimethoate as well as algae treated with cadmium alone or in combination with Dimethoate. Levels of malondialdehyde (MDA) and total antioxidant in cells, as well as the activity of ascorbate peroxidase (APX) soar in Spirogyra sp., exposed to Dimethoate and/or cadmium (alone or simultaneously). Also Spirogyra’sexposure to cadmium and/or Dimethoate significantly increases catalase (CAT) activity. However, levels of carotenoids in Spirogyra sp., treated with both cadmium and Dimethoate, decline significantly, with no significant change found in catalase activity of Spirogyra sp., exposed to 100 and 200 mg L-1 of Dimethoate, in comparison to the control group. However, CAT activity rises significantly in Spirogyra sp., treated with 400 mg L-1 of Dimethoate. Cadmium can cause cytotoxicity in 1 mg L-1 concentration of the green algae(Spirogyra sp.). On the whole, investigating the biological and biochemical markers in Spirogyra sp., exposed to different concentrations of Dimethoate, has revealed some concentration-dependent toxicity. Furthermore, Dimethoate can synergistically increase toxicity and bioavailability of cadmium in Spirogyra sp.
显示更多 [+] 显示较少 [-]Facile Synthesis of Zn-TiO2 Nanostructure, Using Green Tea as an Eco-Friendly Reducing Agent for Photodegradation of Organic Pollutants in Water
2018
tavakoli, F. | Badiei, A.
The present study synthesizes Zn-TiO2 photocatalyst via a simple and economic green rout, in which Green Tea is applied as a green reducing agent due to the presence of polyphenols Molecules. Polyphenol molecules in green tea act as a reductant, thus changing Zn2+ to metallic Zn. The by-produced nanocmposites are characterized by using XRD, FESEM, EDS, and DRS. Zn-TiO2 photocatalyst possesses great efficient charge separation properties. In order to investigate the presence of Zn, different weight ratio of Zn to TiO2 (viz. 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, and 50 wt%) have been synthesized and their performance in Acid Orange 7 (AO7) photodegradation, compared with pure TiO2. According to the results, the compound with 25 wt% Zn shows 97% degradation of AO7 as a model pollutant. Also, it has been shown that after three tests with EDTA, benzoic acid, and under Ar gas, photodegradation of AO7 with Zn-TiO2 photocatalyst mainly depends on photogenerated holes.
显示更多 [+] 显示较少 [-]Wastewater Remediation via Modified Activated Carbon: A Review
2018
Hasan, M.B. | Hammood, Z.A.
The magnetic derivative of Activated Carbon (AC) is a promising new technique to isolate and recover consumed adsorbent. In this light, the current research seeks to summarise the magnetisation rout of AC and its applications, while identifying both benefits and drawbacks of different synthetic routs. Several methods, such as chemical co-precipitation, hydrothermal, impregnation, ball milling, and one-step synthetic routs, have been studied by previous researchers. Among these methods, chemical co-precipitation is simple, extensively adapted for Magnetic Activated Carbon (MAC) syntheses. In general, the magnetic derivatives of AC show a reduction in the surface area and pore volume, due to introduction of magnetic nanoparticles. Magnetisation enhances contaminants' adsorption, despite the reduction in surface area. It allows elimination of contaminants, barely treated by pristine AC due to the introduction of magnetic materials. Developments in synthetic procedures could overcome the destructive influence of acidity on MAC, providing a shield against it. MAC has been used in several applications, including organic and inorganic contaminant removal. Medically, MAC is used to lead drugs to a specific organ and, thus, reduce damages to non-affected organs. It can be said that the preparation method did not obstruct MAC application for specific contaminant adsorption. MAC regeneration has been reported for several sorption cycles, making the process sustainable and cost-effective. Future work could further develop the synthetic route and enhance the characteristics of the produced composite. It also may consider the influence of iron on the treated water, depending on its proposed usage.
显示更多 [+] 显示较少 [-]Estimation of Annual Effective Dose of 222 Rn and 220 Rn in indoor Air of Rohilkhand region, Uttar Pradesh state, India
2018
Rastogi, N. | Singh, I. | Goswami, V.
The annual exposure to indoor radon and thoron imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive of indoor radon and thoron concentrations that were carried out in Rohilkhand region with health risk to the dwellers in the region. In present study, Solid State Nuclear Track Detectors (SSNTDS ) based twin chamber dosimeter with LR-115 track detector were used for estimating Radon (222Rn) and Thoron (220Rn) gas concentration levels in the dwellings of Moradabad city. The average Radon and thoron concentration levels in the studied dwellings were found to vary from 13.5 to 21.8 Bq m-3 and thoron concentrations is found to vary from 11.7 to 19.5 Bqm-3 and its corresponding geometric mean of equilibrium-equivalent 222Rn and 220Rn concentration were found 7.07 to 1.7 Bqm-3 . The total annual effective dose due to the exposure to radon and thoron was found to vary from3.7 to 6.2 mSv/y whereas from thoron found to vary from 0.3 to 0.61 mSv/y.
显示更多 [+] 显示较少 [-]Ecological risk assessment of heavy metals in Hurghada coastal sediment, Red Sea, Egypt
2018
Abdelkader, A. I. | Abuelregal, M. | El-Metwally, M.E. | Hassaan, M. A. | Sanad, E. F.
Twenty samples of Ø3, Ø4 and Ø5 (fine fractions) were collected from four coastal areas (Sheraton, Magawish, Marina and Al mina) in Hurghada, Egypt. Total organic matter (TOM), total organic carbon (TOC) and heavy metals were estimated in the recommended fractions. Results showed that Fe and Pb recorded the highest concentrations with 71.7 and 39 mg/kg respectively. Marina area fractions has the highest carbonate content varied between 50.7 and 65.7 while Magawish area fractions have the lowest organic matter content and carbonate between 10% and 9.40%. On the other hand, Sheraton area has the highest organic matter content. The Principal Component Analysis) PCA) indicate the anthropogenic sources of Zn and Pb at the Red Sea coast based on Sediment Quality Guidelines(SQGs).According to the Enrichment factor (EF) and the geo-accumulation factor (Igeo), Cu and Pb were the highest enriched elements due to anthropogenic contamination; consequently, the studied areas were classified as moderately to highly contaminate by Cu and Pb at Hurghada.
显示更多 [+] 显示较少 [-]Assessment of Pb and Ni contamination in the topsoil of ring roads' green spaces in the city of Hamadan
2018
Sobhan Ardakani, Soheil
Due to rapid industrialization and urbanization, environmental pollution has become a major concern in developing countries; therefore, the main objective of the current study is to determine heavy metal contents of Pb, and Ni for 42 topsoil samples, collected from 14 green spaces along the 1st and 2nd ring roads in Hamedan City in 2016. For this purpose, after determining some chemical properties as well as acid digestion of soil samples, Pb and Ni concentrations have been found in the soil samples with ICP-OES. All statistical analyses have been conducted, using SPSS 18.0 statistical package, with the results showing that the metal levels in soil samples, collected from green space of 1st and 2nd ring road, have been 34.86±10.28 and 41.57±10.08 mg/kg for Pb and 14.0-20.33 and 14.0-20.0 mg/kgfor Ni, respectively. Also the mean concentration of Pb and Ni have been lower than MPL. According to heavy metal concentration maps, the spatial distribution patterns of Pb, and Ni contents in the soil samples are generally similar along the 1st and 2nd ring road. Due to the fact that traffic volume in the 2nd ring was higher than the 1st one, there has been a significant difference in the mean contents of Pb between the topsoil samples, collected from the 1st and 2nd ring roads; therefore, it is recommended to keep environmental health in order to control the anthropogenic sources, causing the pollutants discharge into the environment is recommended.
显示更多 [+] 显示较少 [-]Arsenic Health Risk Assessment through Groundwater Drinking (Case Study: Qaleeh Shahin Agricultural Region, Kermanshah Province, Iran)
2018
Sobhanardakani, Soheil
Groundwater resources make up an important portion of potable and irrigation water in Iran, making it important to monitor toxic elements of pollutants in these resources in order to protect the inhabitants' health. The current study has been carried out to assess the health risks, caused by trivalent inorganic arsenic-polluted groundwater in Qaleeh Shahin Plain, an important agricultural region in Kermanshah Province. For this purpose, in total 20 groundwater wells have been chosen randomly. The samples have been filtered (0.45 μm) and preserved with HNO3 to a pH level lower than 2, then to be taken in acid-washed polyethylene bottles and kept at a temperature of 4 °C for further analysis. Finally, As(III) concentration has been determined, using ICP-OES with three replications. Results have shown that mean content of As (ppb) in groundwater samples were 6.0 ± 3.0 for winter and 9.0 ± 6.0 for summer in 2014. Also, according to the results, the computed values of the hazard quotient (HQ) and target risk (TR) of groundwater samples were below 1 and less than 10E-06, respectively; therefore, non-carcinogenic effect (chronic risk) and carcinogenic exposure are not likely for the inhabitants of this study area. However, due to over and long-term use of agricultural inputs in the study area, it is recommended to have some paramount consideration for better management and care of using agricultural inputs, especially chemical fertilizers, arsenical pesticides, or herbicides, and for treatment of As-polluted groundwater with proper removal methods prior to preparation of drinking water.
显示更多 [+] 显示较少 [-]A Review of on Environmental Pollution Bioindicators
2018
Asif, Nayyab | Malik, Muhammad | Chaudhry, F.N.
Qualitative status of the environment is signaled by a group of indicators, known as bioindicators, several of which are responsible for showing progressive impacts of different types of pollutants. Having addressed the influence of various bioindicators in environmental pollution, it has been revealed that bioindicators are sensitive to any disturbance in any environment. With regards to the pollution, the quality of an ecosystem can be judged by an organism, which is actually an indicator and play a key role in monitoring its changes. A reliable and cost effective way to evaluate the changes in the environment is possible by means of indicator species as ecological indicators, yet selecting a specific indicator poses a real challenge, followed by its identification as well as relation among indicators and their particular applications. As a result, environmental, ecological, and biodiversity indicators fulfill their goal of monitoring environmental quality. The current situation requires cost effective bioindicators along with their reliability to detect and mitigate the impacts of pollution in our environment.
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