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871.
在发达和发展中国家找到改善生活水平及预期增长的一个可持续发展道路的压力正在增加.达到可持续需要有关生产和清楚行为的根本改变.发现使用低能耗和原材料(产生较少的废弃物)提供较好能力的方法能够有助于世界范围生活水平的改善.特别是在过去十年中,许多企业家对于可持续采取了更加负责的态度,例如在经济效益、与利益相关者的社会对话和共同的社会责任领域.公司正在认识到他们必须与广大的合作伙伴和利益相关者合作,在市场中变得更可持续和成功.  相似文献   
872.
Processed ball clay samples used in the production of ceramics and samples of the ceramic products were collected and analyzed for the presence and concentration of the 2,3,7,8-Cl substituted polychlorinated dibenzo-p-dioxins and -furans (PCDDs/PCDFs). The processed ball clay had average PCDD concentrations of 3.2 ng/g toxic equivalents, a congener profile, and isomer distribution consistent with those found previously in raw ball clay. The PCDF concentrations were below the average limit of detection (LOD) of 0.5 pg/g. The final fired ceramic products were found to be free of PCDDs/PCDFs at the LODs. A consideration of the conditions involved in the firing process suggests that the PCDDs, if not destroyed, may be released to the atmosphere and could represent an as yet unidentified source of dioxins to the environment. In addition, the PCDDs in clay dust generated during manufacturing operations may represent a potential occupational exposure.  相似文献   
873.
Active pharmaceutical ingredients (APIs) from medications can enter the environment as trace contaminants, at individual concentrations generally below a part per billion (microg/L). APIs enter the environment primarily via the discharge of raw and treated sewage. Residues of unmetabolized APIs from parenteral and enteral drugs are excreted in feces and urine, and topically applied medications are washed from skin during bathing. These trace residues may pose risks for aquatic life and cause concern with regard to subsequent human exposure. APIs also enter the environment from the disposal of unwanted medications directly to sewers and trash. The relative significance of this route compared with excretion and bathing is poorly understood and has been subject to much speculation. Two major aspects of uncertainty exist: the percentage of any particular API in the environment originating from disposal is unknown, and disposal undoubtedly occurs from a variety of dispersed sources. Sources of disposal, along with the types and quantities of APIs resulting from each source, are important to understand so that effective pollution prevention approaches can be designed and implemented. Accumulation of leftover, unwanted drugs poses three major concerns: (i) APIs disposed to sewage or trash compose a diverse source of potential chemical stressors in the environment. (ii) Accumulated drugs represent increased potential for drug diversion, with its attendant risks of unintentional poisonings and abuse. (iii) Leftover drugs represent wasted healthcare resources and lost opportunities for medical treatment. This paper has four major purposes: (1) Define the processes, actions, and behaviors that control and drive the consumption, accumulation, and need for disposal of pharmaceuticals. (2) Provide an overview of the diverse locations where drugs are used and accumulate. (3) Present a summary of the first cataloging of APIs disposed by a defined subpopulation. (4) Identify opportunities for pollution prevention and source reduction.  相似文献   
874.
875.
The current requirements and status of air quality modeling of hazardous pollutants are reviewed. Many applications require the ability to predict the local impacts from industrial sources or large roadways as needed for community health characterization and evaluating environmental justice concerns. Such local-scale modeling assessments can be performed by using Gaussian dispersion models. However, these models have a limited ability to handle chemical transformations. A new generation of Eulerian grid-based models is now capable of comprehensively treating transport and chemical transformations of air toxics. However, they typically have coarse spatial resolution, and their computational requirements increase dramatically with finer spatial resolution. The authors present and discuss possible advanced approaches that can combine the grid-based models with local-scale information.  相似文献   
876.
Two mathematical models of the atmospheric fate and transport of mercury (Hg), an Eulerian grid-based model and a Gaussian plume model, are used to calculate the atmospheric deposition of Hg in the vicinity (i.e., within 50 km) of five coal-fired power plants. The former is applied using two different horizontal resolutions: coarse (84 km) and fine (16.7 km). More than 96% of the power plant Hg emissions are calculated with the plume model to be transported beyond 50 km from the plants. The grid-based model predicts a lower fraction to be transported beyond 50 km: >91% with a coarse resolution and >95% with a fine resolution. The contribution of the power plant emissions to total Hg deposition within a radius of 50 km from the plants is calculated to be <8% with the plume model, <14% with the Eulerian model with a coarse resolution, and <10% with the Eulerian model with a fine resolution. The Eulerian grid-based model predicts greater local impacts than the plume model because of artificially enhanced vertical dispersion; the former predicts about twice as much Hg deposition as the latter when the area considered is commensurate with the resolution of the grid-based model. If one compares the local impacts for an area that is significantly less than the grid-based model resolution, then the grid-based model may predict lower local deposition than the plume model, because two compensating errors affect the results obtained with the grid-based model: initial dilution of the power plant emissions within one or more grid cells and enhanced vertical mixing to the ground.  相似文献   
877.
Oligomers of poly(3-hydroxybutyric acid) (P(3-HB)) were prepared by partial degradation of high molecular weight P(3-HB) dissolved in 1,2-dichloroethane/water mixture in the presence of p-toluene sulfonic acid (p-TSA). The water-soluble fraction of the resulting oligomers was extracted from the mixture with neutral sodium phosphate buffer. Capillary zone electrophoresis showed that the aqueous extracts were composed of two series of oligomers. The first one was composed of one to seven P(3-HB) oligomers (O(3-HB)). In contrast, the second series was composed of four oligomers characterized by the presence of a terminal C=C bond [O’(3-HB)]. Both series of oligomers behaved differently insofar as their fate in aqueous medium was concerned. The 0(3-HB) compounds were stable over a period of 2 months. On the other hand, the population of the O’(3-HB) oligomers varied, the proportion of oligomers increasing with aging time.  相似文献   
878.
The weekly cycles of atmospheric ozone (O3) are of interest because they provide information about the response of O3 to changes in anthropogenic emissions from weekdays to weekends. The weekly behavior of O3 in Chicago, IL; Philadelphia, PA; and Atlanta, GA, is contrasted. In Chicago and Philadelphia, maximum 1-hr average O3 increases on weekends. In Atlanta, O3 builds up from Mondays to Fridays and declines during weekends. In all three areas, volatile organic compound (VOC)/nitrogen oxides (NOx) ratios are higher during weekends, resulting from greater than proportionate decreases in NOx relative to VOC emissions. The VOC/NOx ratios correlate with maximum 1-hr O3 concentrations in Chicago, a response consistent with a VOC-sensitive airshed. A weak correlation between O3 concentrations and VOC/NOx ratios in Philadelphia suggests the impact of transported O3, which is formed in upwind VOC-sensitive locations that may be hundreds of kilometers away. Ozone concentrations in Atlanta do not correlate with VOC/NOx ratios but with concentrations of NOx and total reactive nitrogen (NOy) carried over from the previous day. When data from 1986-1990 and 1995-1999 are compared, only small differences in the weekly behavior of O3 are observed in Chicago and Philadelphia. The day-of-week differences in O3 are amplified in the more recent period in Atlanta, a possible result of urban growth.  相似文献   
879.
In order to evaluate the stress effects of flumioxazin (fmx) on grapevine, a non-target plant (Vitis vinifera L.), physiological parameters such as carbohydrate content, water status or nitrogenous metabolites were investigated on fruiting cuttings and plants grown in vineyard. In the leaves of cuttings, the soil-applied herbicide induced stress manifestations including a decrease of the dry weight percentage and the soluble carbohydrate content during the first week after treatment. Thereafter, a decrease of the osmotic potential was observed, as well as a decrease of total protein content and a parallel accumulation of free amino acids, including proline. Altogether, these results suggest that soil-applied fmx induced a stress in grapevines, leading to leaf proteolysis. However, this stress was partially recovered 3 weeks after herbicide application, suggesting that the cuttings were capable to adapt to the fmx exposure. In the vineyard, the flumioxazin effects were still significant 5 months after the treatment, particularly in the CH cv. They included a decrease of the leaf dry weight percentage and soluble carbohydrate content, as well as an increase of the osmotic potential. The decrease of leaf soluble carbohydrates may have dramatic consequences for the berry growth and the reserve constitution. Moreover, treated plants were characterized by a decrease of the free amino acid content and an accumulation of ammonium, while the protein level did not significantly increase, suggesting a degradation of amino acids. The alteration of carbon and nitrogen status after herbicide treatment may affect the grapevine vigour in a long term.  相似文献   
880.
The measurement and induction of mixed function oxyigenases (MFOs) of limnetic gastropods were investigated to estimate their suitability as biomarkers. A determination of MFO activities was performed through the measurement of ethoxyresorufin-O-dealkylase (EROD), pentoxy-(PROD) and benzoxyresorufin-O-dealkylase-activity (BROD). Optimal measuring conditions of these activities were investigated in preparations of the digestive gland of 4 species of limnetic gastropods. Results indicate that MFO-activity inhibiting substances are accumulating in the microsomal pellet, the fraction commonly used for the measurement of MFO-activities. Therefore, the fraction used for induction studies was the postmitochondrial supernatant (PMS). EROD, PROD, and BROD activity ofPlanorbis planorbis andPlanorbis carinatus were measured after a treatment with Aroclor 1254 for 1–17 days. Maximal induction of EROD and PROD were 6 and 10 times the value in the control group ofP. carinatus, respectively induction inP. planorbis was lower. BROD-activity could not been measured inP. planorbis. InP. carinatus, BROD-activity increased to a maximum of 2 times after traetment with Aroclor 1254. The level of induction of EROD-activity is comparable to results described in analog studies with fish.  相似文献   
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