Purpose
Screening out cadmium (Cd) excluding cultivars of a crop in agricultural production is an effective way to prohibit Cd entering into food chain.Methods
A judging criterion for Cd-excluding cultivars based on food safety was suggested and used in the identification of Cd-excluding welsh onion (Allium fistulosum L.) cultivars. A pot culture experiment was carried out to screen out Cd-excluding cultivars, of which the results were confirmed by plot experiments. The relevant factors of Cd accumulation in the pseudostem were analyzed and used in the correlation analysis aiming to study the low Cd accumulation mechanisms.Results
The concentration of Cd in the pseudostem of welsh onions was 0.08?C0.20, 0.18?C0.41, and 0.26?C0.61?mg/kg fresh weight (FW) under three treatments (1.0, 2.5, and 5.0?mg/kg), respectively. The significant (p?0.05) difference in the concentration of Cd in the pseudostem was observed among 25 welsh onion cultivars, but Cd contamination in soil had little influence on biomass and the contents of soluble sugar, NO 3 ? ?CN, and eight other elements in the tested welsh onion cultivars. Two cultivars were identified as Cd-excluding cultivars, mainly because the accumulation of Cd in their pseudostem was only 0.041?±?0.003 and 0.046?±?0.002?mg/kg FW, and 0.054?±?0.001 and 0.066?±?0.011?mg/kg FW, when growing in plots with Cd concentration of 0.49 and 0.99?mg/kg, respectively.Conclusions
Ribentiegancongwang and Wuyeqi could be identified as Cd-excluding cultivars. Low bioaccumulation factor of the roots was the main mechanism of Cd-excluding welsh onion cultivars. 相似文献Introduction
The effect of oceanic CO2 sequestration was examined exposing a deep-sea bacterium identified as Vibrio alginolyticus (9NA) to elevated levels of carbon dioxide and monitoring its growth at 2,750 psi (1,846 m depth).Findings
The wild-type strain of 9NA could not grow in acidified marine broth below a pH of 5. The pH of marine broth did not drop below this level until at least 20.8 mM of CO2 was injected into the medium. 9NA did not grow at this CO2 concentration or higher concentrations (31.2 and 41.6 mM) for at least 72 h. Carbon dioxide at 10.4 mM also inhibited growth, but the bacterium was able to recover and grow. Exposure to CO2 caused the cell to undergo a morphological change and form a dimple-like structure. The membrane was also damaged but with no protein leakage. 相似文献Introduction
Korea has been making efforts to reduce greenhouse gas (GHG) emissions, including a voluntary commitment to the target of a 30% reduction, based on business-as-usual of the total GHG emission volume, by 2020; 2006 IPCC Guidelines provided default values, applying country-specific emission factors was recommended when estimating national greenhouse gas emissions.Results and discussion
This study focused on anthracite produced in Korea in order to provide basic data for developing country-specific emission factor. This study has estimated CO2 emission factors to use worksheet of which five steps consisted according to the fuel analysis method.Conclusion
As a result, the average of net colorific value for 3 years (2007??2009) was 4,519 kcal/kg, and the CO2 emission factor was calculated to be 111,446 kg/TJ, which is about 11.8% lower than the 2006 IPCC guidelines default value, and about 7.9% higher than the US EPA emission factor. 相似文献Introduction
The paper analyses the environment pollution state in different case studies of economic activities (i.e. co-generation electric and thermal power production, iron profile manufacturing, cement processing, waste landfilling, and wood furniture manufacturing), evaluating mainly the environmental cumulative impacts (e.g. cumulative impact against the health of the environment and different life forms).Materials and methods
The status of the environment (air, water resources, soil, and noise) is analysed with respect to discharges such as gaseous discharges in the air, final effluents discharged in natural receiving basins or sewerage system, and discharges onto the soil together with the principal pollutants expressed by different environmental indicators corresponding to each specific productive activity. The alternative methodology of global pollution index (I GP * ) for quantification of environmental impacts is applied.Results and discussion
Environmental data analysis permits the identification of potential impact, prediction of significant impact, and evaluation of cumulative impact on a commensurate scale by evaluation scores (ESi) for discharge quality, and global effect to the environment pollution state by calculation of the global pollution index (I GP * ).Conclusions
The I GP * values for each productive unit (i.e. 1.664?C2.414) correspond to an ??environment modified by industrial/economic activity within admissible limits, having potential of generating discomfort effects??. The evaluation results are significant in view of future development of each productive unit and sustain the economic production in terms of environment protection with respect to a preventive environment protection scheme and continuous measures of pollution control. 相似文献Background, aim and scope
The influence of pH (range 6.5–8.5) on the uptake of Zn, Cd, Pb, Cu, Ni, Cr, Hg, and As by juveniles of the clam Ruditapes philippinarum was examined in order to understand whether variation in sediment pH has significant repercussions on metal bioaccumulation.Materials and methods
Clams were exposed to sediments collected in three locations in the Gulf of Cadiz (Huelva, Guadalquivir and Bay of Cadiz) and to contaminated particles derived from an accidental mining spill in Spain.Results
With a notable exception of metal Cd, the concentration of metals within clams significantly increased (p?<?0.1) when sediment pH was lowered by one or two units. Moreover, the magnitude of this effect was dependent on the type of sediment contamination.Discussion
Lower pH increases metal solubility and reduces or invert the metal sorption of metals to sediments. Increases in free metal ions in water favors metal uptake by clams, hence pH is an important factor controlling the mobility of these metals within sediments and their subsequent bioaccumulation within biota. Although sediment-water exchange of Cd can increase with acidification, this excess may be counterbalanced by the presence of ligands in seawater preventing the uptake by organism. Besides chlorines, Cd has also an affinity with carbonates and other ligands present in sea water. These Cd-carbonate complexes may reduce the bioavailable to organisms.Conclusions
These results highlight the potential implications of sediment acidification, either due to the storage excess of organic matter or to the forced capture of CO2, on the increasing metal availability to benthic organisms.Recommendations and perspectives
This kind of studies should be increased to address the influence of acidification in the behavior, bioavailability, toxicity, and risk assessment of contaminants associated with sediments either above sub-seabed geological formations in marine environments or in high enriched by organic matter in estuarine areas. Recently, the capture of CO2 in marine environments has been approved and started; it is necessary to address the potential impacts associated with leakages or other events occurring during the procedure of injection and storage of CO2. 相似文献Purpose
The impact of CO2 urban plume in a rural area was investigated by concentrations recorded near surface.Methods
CO2 dry concentrations at three levels near surface were recorded for about 8 months at a rural site. Daily cycles were obtained and directional analysis was made with percentiles. Several functions were used to fit background and plume concentrations and the goodness of fit was evaluated with different statistics, which were also compared.Results
Daily cycle showed a difference of around 2 ppm during the night between the lowest (1.8 m) and the highest (8.3 m) levels. Weighting functions of the directional analysis revealed the influence of the Valladolid urban plume. Two regions were established, with local factors prevailing below 3 m?s?1 and transport dominating above 6 m?s?1. The best fit was achieved with a quadratic function for the background and a cubic function for the plume due to the lack of symmetry observed. Gamma and Weibull distributions were also successfully used. Some statistics, such as the root mean square error (RMSE), stood out when evaluating the goodness of fit, whilst others were discarded due to their extremely low values and the lack of sensitivity against the functions used. Finally, a comprehensive metric merging several statistics was also tested with slight differences against RMSE. 相似文献Background, aim, and scope
Olive oil mill wastewater (OMW), a by-product of the olive oil extraction process, is annually produced in huge amounts in olive-growing areas and represents a significant environmental problem in Mediterranean areas. We studied the impact of OMW dilutions (1:20 and 1:10) on spinach plants in order to evaluate OMW dilutions as a low-cost alternative method for the disposal of this waste.Materials and methods
The effects of OMW dilutions were evaluated on seed germination, shoot and root elongation, biomass production, nutrient uptake and translocation, ascorbic acid content, polyphenols, photosynthetic pigments, and photosynthetic performance of spinach.Results
Plant biomass was more affected than plant height and total chlorophyll; carotenoid and ascorbic acid content progressively decreased with decreasing OMW dilution. Exposure to both OMW dilutions resulted in overaccumulation of total polyphenols, which were negatively correlated to plant biomass and nutrients. Nutrient (Fe, Ca, and Mg) content was insufficient leading to reduced growth. Water use efficiency decreased mainly due to decreased CO2 assimilation rate rather than to a decline of transpiration rate. Disturbances in photosystem II (PSII) photochemical efficiency could be better envisaged by the ratio between variable fluorescence and initial fluorescence (Fv/Fo), which showed much greater amplitude than the maximal photochemical efficiency of PSII photochemistry (Fv/Fm).Conclusions
From the data obtained, it is suggested that 1:20 OMW dilutions are still phytotoxic and that higher OMW dilutions should be used in order to use this waste for the irrigation of spinach plants. 相似文献Purpose
The discharge of colored effluents from industries is an important environmental issue and it is indispensable to remove the dyes before the water gets back to the rivers. The magnetic adsorbents present the advantage of being easily separated from the aqueous system after adsorption by positioning an external magnetic field.Methods
Magnetic N-lauryl chitosan (L-Cht/??-Fe2O3) particles were prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. Remazol Red 198 (RR198) was used as a reactive dye model for adsorption on L-Cht/??-Fe2O3. The adsorption isotherms were performed at 25°C, 35°C, 45°C, and 55°C and the process was optimized using a 23 factorial design (analyzed factors: pH, ionic strength, and temperature). The desorption and regeneration studies were performed in a three times cycle.Results
The characterization of the material indicated that the magnetic particles were introduced into the polymeric matrix. The pseudo-second order was the best model for explaining the kinetics and the Langmuir?CFreundlich was the best-fitted isotherm model. At room temperature, the maximum adsorption capacity was 267?mg?g?1. The material can be reused, but with a decrease in the amount of adsorbed dye.Conclusions
L-Cht/??-Fe2O3 is a promising material to remove RR198 and probably other similar reactive dyes from aqueous effluents. 相似文献Rapid increase in carbon dioxide emission triggers climate change, while climate change poses a threat to food security. On the other hand, emission increase as a result of agricultural production continues. Considering this cycle, it is thought that examining the relationship between agricultural production and carbon dioxide emissions can help countries take emission-reducing measures and develop policies to ensure food safety. With this thought, a common correlated effect estimator was used in this study to explain the relationship between crop and livestock production index and carbon dioxide emission of 184 countries with the use of data for the period of 1998–2014. Countries were classified under four categories: low-income countries, lower middle–income countries, upper middle–income countries and high-income countries. According to DCCE test results, it was reported that a 1% increase in crop production index had effect on CO2 emission only in lower middle–income countries. A 1% increase in livestock production index, on the other hand, was reported to increase CO2 emission rates by 0.28, 0.49, and 0.39 in lower middle–income, upper middle–income, and high-income countries, respectively. When evaluated in general, it could be stated that livestock breeding has a higher effect on CO2 emission in agricultural production. The findings of the present study revealed that countries need to improve agricultural production methods in ways to minimize the positive association between vegetative and livestock production in accordance with their level of development, to adopt more environment-friendly agricultural technologies and to endorse international environmental policies.
相似文献Purpose
For countries in which the stone industry is well developed, opposition to quarry and plant waste is gradually increasing. The primary step for waste control and environmental management is to define the problem of concern. In this study, natural building stone wastes were classified for the first time in the literature.Methods
Following on-site physical observations and research at more than 50 quarries and 20 plants, stone wastes were classified as (1) solid, (2) dust and (3) semi-slurry, slurry and cake.Conclusions
As a result of this study, the characteristics of wastes, their main environmental threats and the industries in which wastes could be used were defined for each group. 相似文献Purpose
This study contains some new findings connected to the photolysis of the drug paracetamol (hereinafter APAP) especially in light of estimating natural conditions, and it will offer information to better evaluate environmental problems connected with this widely used analgesic agent. Only a few studies, so far, have focussed on the photodegradation process of APAP in the natural environment, and the question about the role of the colored/chromophoric dissolved organic matter (CDOM) and nitrate (NO 3 ? ) as photoinductors is almost open.Methods
APAP dissolved in freshwater and pure laboratory water in the presence and absence of CDOM and NO 3 ? ions was irradiated using weak-energy photon energies simulating natural conditions.Results
CDOM and NO 3 ? as photoinductors produced only the slow phototransformation of APAP under weak energy radiation, and APAP seemed to be practically resistant to direct photolysis under weak radiant energies available in natural conditions. The estimated reaction efficiencies, in addition to half-lives, speak for that NO 3 ? and CDOM do not act as quite independent photoinductors but their effect in conjunction (CDOM?CNO 3 ? ?Cwater) is stronger than the separate ones. The principal phototransformation intermediates of APAP were mono-hydroxy derivatives, depending on available photon energies formed via ortho- or meta-hydroxylation, possessing substantial power of resistance to further specific transformation reactions.Conclusions
The estimated half-life of the phototransformation of APAP in the natural aqueous environment and in the presence of suitable photoinductors will be about 30?days or more. 相似文献Introduction
The copper bioaccumulation by the floating Lemna minor and by the completely submerged Ranunculus tricophyllus as a function of exposure time and copper concentration was studied, with the aim of proposing these species as environmental biosensors of the water pollution.Results
The results show that both these aquatic angiosperms are good indicators of copper pollution because the copper uptake is the only function of metal concentration (water pollution).Conclusion
Uptake behavior is reported as a function of the time and concentration, based on the results of a 3-year study. Kinetic evaluations are proposed. 相似文献Purpose
This paper presents a novel approach to interpret ground-level O3 with the measured atmospheric stability index (ASI).Methods
O3 concentrations were monitored by automatic analysers at three types of stations: traffic site, residential site and regional background site in 2005, and the ASI was simultaneously measured by observing radon and its short-lived decay products.Results
The observed results showed a clear annual variation of O3 concentrations with a maximum in spring, relatively high at the regional background site over 120?ppb, and lower at the residential and traffic sites at about 70?ppb. ASI gives information about the dilution properties of the lower boundary layer and allows to highlight the relevant role of the dilution factor in determining atmospheric pollution events. We demonstrated the analysis of O3 night peak episodes with vertical wind and ASI.Conclusions
With the advantage of ASI and vertical wind profiles, it was possible to isolate particular photochemical pollution phenomena of O3 peaks from the free troposphere reservoir or formed by local reactions. This shows that the index constitutes a powerful and valuable tool for describing O3 night-peak episodes at background station. 相似文献Introduction
Canola, which is genetically modified (GM) for tolerance to glyphosate, has the potential to become established as a new glyphosate resistant weed, thus reducing the effectiveness of glyphosate.Methods
Volunteer from dormant canola seeds produced thousands of plants per hectare in the fourth year (2011) following a 2007 crop harvest. This occurred with no additional canola seed production since the 2007 harvest.Results
Volunteer plants following harvests of annual crops are typically only a problem for the first year after harvest. In California, glyphosate is the core herbicide on over a million hectares of high value row, tree, and vine crops and new glyphosate resistant weeds reduce the effectiveness of glyphosate.Conclusions
The combination of dormant seed and herbicide resistance makes GM glyphosate-resistant canola a new and difficult California weed which was first observed in the winter of 2009. 相似文献Implications: Full-scale operation of anaerobic codigestion of food waste with municipal sludge is viable, but it is still new. There is a lack of readily available scientific information on the quality of raw biogas, as well as on potential emissions from power generation using this biogas. This research developed scientific information with regard to quality and quantity of biogas from anaerobic co-digestion of food waste and municipal wastewater sludge, as well as impacts on air quality from biopower generation using this biogas. The need and performance of conditioning/pretreatment systems for biopower generation were also assessed. 相似文献