The adoption of environmentally sustainable techniques by cooperatives and small companies results in specific difficulties rarely discussed in the literature. This paper describes an action-research carried out by seafood cultivators and university researchers in Guanabara Bay, which resulted in the substitution of the previous technique, based on extraction, by one without negative environmental impacts. The economic results have been satisfactory, so it can be expected that this activity may become more widespread in the region. 相似文献
The chrome (Cr) is a metal utilized in various industrial sectors and its investigation in the environment is necessary, for the Cr (III) contain aessential micronutrients in the human nourishment and the Cr (VI), on the other hand, is toxic. In the present work soil contamination with Cr was realized in drainagelysimetersset in concentrations of 0, 200, 400, 600, 800 and 1000 mg kg−1 of total Cr, with the intuition to determine the total Cr and Cr (VI) flux in leached water, in soil and in plants of lettuce (Lactuca sativa L.). In the lysimeters were cultivated four plants, in three cultivation circles. In the end of the cultivations was observed, that the total applied Cr leached in the soil, evidencing the Cr mobility in latossoil with simulant characteristics to the ones utilized in this paper. The Cr (VI) concentrations in the soil increased soon after the treatment applications, but tend to decrees in the time elapse, the same tendences were observed for the total Cr concentrations in the leached water. The Cr absorption by plants was related to the Cr disponibility in the soil, for the soil concentration and the plants decreased with time passing. The Cr mobility in the soil possibilitated the groundwater contamination presenting risks to the water quality and, consequently to public health. 相似文献
Ozone and a Fe2+/TiO2-based catalyst were examined in the degradation of a synthetic solution of benzene toluene and xylene (BTX) in an advanced oxidation process (AOP). The catalyst beads were made from the slurry waste of aluminum production process, by inserting the TiO2 content and subsequent calcination. The reduction of the BTX concentration load was monitored by the reduction of chemical oxygen demand (COD) and BTX concentration. Different levels were used on factors: pH, time of treatment, initial concentration of BTX, and percentage of TiO2. The process was conducted in a bubble column reactor with the insertion of catalyst beads. A response surface methodology technique (CCD) was used to build a model based on COD reduction results. The model was optimized using the normal-boundary intersection (NBI) algorithm to maximize COD reduction and minimize the variance attributed to the process. Optimization led to COD reductions of 80% in 2 h of experiment. Correlation analysis of coefficient models from experimental data R2adj was 0.9966, showing a good fit of model data. In the optimized conditions, the possible increase of the biodegradability ratio of the BTX solution, through the biochemical oxygen demand (BOD) and COD, was also analyzed. Under pre-treatment conditions, the BOD/COD ratio was 0.13. After the treatment, it increased to 0.56.
Developing a biomaterial that functions as a scaffold (osteoconductor), combined with a growth factor (osteoinductor), is of great interest for clinical application in oral and maxillofacial surgery. Growth hormone (GH) is a good candidate, as it is a major regulator of postnatal bone growth and remodeling. Pure PLGA and 70/30 PLGA/PCL matrices were prepared by the solvent evaporation method, combined or not with GH, and tested for toxicity and cell viability using an MTT assay with NIH3T3 mouse cells (ATCC). Cell toxicity was assessed at 24, 48, 72 h, and 7 days of biomaterial exposure to culture medium. All polymers had high cell viability rates. However, from 48 h onwards, the groups with GH-polymer combinations had better results than the polymer groups without association with GH when compared to the control group. At 7 days of culture, only the pure PLGA matrix showed a significant difference from the control group. These results may suggest a preference of cells for the presence of GH in the biomaterial in culture medium, especially in the PLGA matrix. GH appeared to contribute to the increase in cell viability observed at some assessment time points, especially when combined with PLGA as compared to pure PLGA. 相似文献
Environmental Science and Pollution Research - The present study investigated the performance of an integrated system, combining the sequential use of microalgae (MA) and vertical flow constructed... 相似文献
The present study investigates the application of a noncommercial peroxidase enzyme, which was extracted from rice bran, to decolorize wastewater that was simulating effluent from a textile manufacturer using a red dye in its coloration process. 相似文献
Journal of Material Cycles and Waste Management - Several sustainable white ceramic composites were prepared from 3 to 7 wt.% of hazardous toner waste, 30–40% of spent foundry sand,... 相似文献
In the recent past, the Sepetiba Bay watershed, located in the Rio de Janeiro State, Brazil has experienced rapid industrial
development and population growth, as well as an increase in water pollution and environmental degradation. To analyze the
complex interrelationships among the agents affecting the Sepetibza Bay environment, a system dynamics model was developed.
The model builds on extensive studies conducted for the watershed, and simulates different hypotheses of economic growth and
of demographic expansion. Thus, it can be used as a decision support tool for the identification of investment priorities
and policy analyses under various scenarios. In order to provide a comprehensive approach to the environmental management
of the Sepetiba Bay watershed, the model had to consider only the most relevant aspects of the behavior and the key interactions
among agents operating in the watershed. In this article, the model’s structure is presented together with some of its main
results. 相似文献
Gas movement through soils is important for ecosystems and engineering in many ways such as for microbial and plant respiration, passive methane oxidation in landfill covers and oxidation of mine residues. Diffusion is one of the most important gas movement processes and the determination of the diffusion coefficient is a crucial step in any study. Five laboratory methods used for measuring the relative gas diffusion coefficient (D(s)/D(o)) were compared using a loamy sand, a porous media commonly found in agricultural fields and in several engineered structures, such as in landfill final covers. In the absence of macropores, all methods gave rather similar values of D(s)/D(o). Methods allowing the study of microscale variability indicated that the presence of macropores highly influenced gas movement, thus the value of D(s)/D(o), which, near a macropore may be one order of magnitude higher than in regions without macropores. Repacked columns do not allow the study of heterogeneity in D(s)/D(o). Natural spatial variability in D(s)/D(o) due to water distribution and preferential pathways can only be studied in large systems, but these systems are difficult to handle. Advantages and disadvantages of each method are discussed. 相似文献