首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Environmental Science and Pollution Research - Breast cancer (BC) is one of the most common and recurring diseases and the second leading cause of death in women. Despite prevention, diagnostics,...  相似文献   

2.
In soil, chromium can be found in two main valence states: hexavalent Cr(VI) and trivalent Cr(III). In this study, we investigated the impact of Cr on photosynthetic gas exchange, photosystem II (PSII) activity, Cr translocation and accumulation, proline content and alkaloids production, i.e. scopolamine and hyoscyamine, in Datura innoxia. Cr uptake was influenced by its oxidation state and its concentration in growth medium. The plant roots were determined as being the main organ of Cr accumulation. Cr(VI) was more toxic than Cr(III) as indicated by reduction in plant biomass and net photosynthesis. The stomatal conductance showed a similar trend to that of photosynthetic capacity. Cr(III) and Cr(VI) had a different impact on substomatal CO(2) concentration then Cr toxicity was related to its oxidation states. In plants stressed with a Cr(VI) excess, a down regulation of PSII activity was observed with an impairment of photochemical activity. Indeed, the maximum quantum yield of PSII (F(v)/F(m)), the quantum yield of PSII (PhiPSII) and the efficiency of excitation capture by open centers (F'(v)/F'(m)) decreased. Cr(III) had little effects on PSII primary photochemistry, whatever its form induces an increase of scopolamine content without changes in hyoscyamine content in leaves of D. innoxia. These results provide that chromium contamination can change the secondary metabolites composition of leaves, thereby, impacting the quality, safety and efficacy of natural plant products synthesized by D. innoxia plants.  相似文献   

3.
Environmental Science and Pollution Research - The presence of volatile benzene series compounds (VBSCs) in the environment is continually increasing, with the potential for negative effects on...  相似文献   

4.
An intercalibration study on organobromine compounds has been conducted to evaluate the accuracy and reliability in the analysis of brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and their related compounds like polybrominated and monobromo-polychlorinated dibenzodioxins and -furans (PBDDs/DFs, MoBPCDDs/DFs). This paper reports the results for these compounds in 'Mixed Standard Solutions' and 'Air-Dried Sediment'. The relative standard deviations (RSDs) for PBDEs, PBDDs/DFs and MoBPCDDs/DFs in mixed standard solutions ranged from 9% to 24%, 4% to 20% and 8% to 27%, respectively. The results of this study are better than those reported in earlier international interlaboratory studies due to general improvement in analytical methods and an increasing number of available authentic standards, particularly for PBDEs. In the analysis for higher brominated compounds such as octabromodibenzodioxin, the participants were advised to optimize the calibration curves befitting the range of concentrations found in samples because variation of relative response factors was noted. The results for 'Air-Dried Sediment' were also reasonable with RSDs from 10% to 38% for PBDEs, 8% to 38% for PBDDs/DFs and 17% to 36% for MoBPCDDs/DFs. In the sediment sample, possible errors in the sample pretreatment and/or interference by other compounds/impurities were indicated. The concentrations of pentabromodiphenylether, BDE100, varied more than the other PBDE isomers due to its poor separation in some chromatographic conditions. In addition, interference by PBDEs was observed in the analysis for PBDFs. Potential degradation/secondary formulation of PBDEs and PBDFs during the Soxhlet extraction were suggested when copper powder was added into the sediment samples. Inspite of these observations, the results in this study are better than those reported in other interlaboratory studies due to the advice given to participants for improving the results. Compared with the results for PCDDs/DFs (5-23% RSDs) and Co-PCBs (6-24% RSDs), the RSDs for most of the organobromine compounds were high, indicating an immature QA/QC approach for the analysis of PBDEs and related compounds in comparison to common chlorinated dioxins.  相似文献   

5.
Bisphenol A (BPA) has been found in plastic food containers, paper currencies and toys. BPA has been reported for various adverse health concerns including reproduction, development and carcinogenesis. These potential health implications have led to increasing use of alternative bisphenols such as bisphenol F and bisphenol S among many. However, little is known about the toxicity of alternative bisphenols and most of the toxicological information is limited to endocrine disrupting potentials. In this study, we evaluated cytotoxicity and the genotoxic potentials of several bisphenol compounds, and identified the mechanism of genotoxicity using a panel of mutant chicken DT40 cell lines deficient in DNA repair pathways. Several bisphenols including bisphenol AP, bisphenol M, or bisphenol P exerted genotoxic potentials that are greater than that of BPA. Generally RAD54−/− mutant cells were the most sensitive to all bisphenols except for bisphenol F, suggesting the induction of DNA double-strand breaks that could be rescued by homologous recombination. Genotoxic potential of bisphenols was confirmed by chromosomal aberration assay and γ-H2AX foci forming assay between wild-type and RAD54−/− mutant. Among the tested bisphenols, BPP at 12.5 μM showed the greatest genotoxic potency, inducing chromosomal aberration and γ-H2AX foci in RAD54−/− mutant by 2.6 and 4.8 folds greater than those in wild-type, respectively. Our results clearly show several alternative bisphenols can cause genotoxicity that could be rescued by homologous recombination pathway, and some bisphenols induced even greater genotoxic potentials than that of BPA.  相似文献   

6.
In this study, a relevant literature has been reviewed focusing on the carbon dioxide capture technologies in general, such as amine-based absorption as conventional carbon dioxide capturing technology, aqueous ammonia-based absorption, membranes, and adsorption material (e.g., zeolites, and activated carbons). In more details, metal organic frameworks (MOFs) as new emerging technologies for carbon dioxide adsorption are discussed. The MOFs section is intended to provide a comprehensive overview of MOFs including material characteristics and synthesis, structural features, CO2 adsorption capacity, heat of adsorption and selectivity of CO2.  相似文献   

7.
基于DEA模型的区域削减指标分配研究   总被引:2,自引:1,他引:1  
运用数据包络分析(DEA)方法,建立了区域削减指标分配模型,综合分析了2005年全国31个省、市、自治区的主要污染物COD和SO2排放绩效以及水资源、能源的利用效率.分析表明,我国COD、SO2的排放效率、水资源和能源的利用效率比较低,节水节能减排的潜力很大.根据效率原则,得到了全国各地区节能节水减排的削减指标分配表.  相似文献   

8.
综述了钯 /铁、二硫化铁、硫化铁、三氧化二铁、绿锈等含铁化合物在降解六氯乙烷、四氯化碳、五氯乙烷、四氯乙烷、三氯乙烷、三氯乙烯、四氯乙烯等有机氯化物中的应用以及降解机理  相似文献   

9.
Environmental Science and Pollution Research - Competition to gain more market share leads to the development of a dynamic environment and the fulfillment of an improvement cycle in supply...  相似文献   

10.
The sorption and desorption of heterocyclic organic compounds in a complex multisolute system to a natural clayey till was investigated. The composition of the solutes reflect a simplified composition of an aqueous phase in contact with coal tar. Sorption was studied for two ratios (s:l) of clayey till (solid) to aqueous phase (liquid). The effect of the complex mixture of solutes on sorption of the four heterocyclic compounds: benzofuran, dibenzofuran, benzothiophene, and dibenzothiophene is evaluated by comparison with their sorption measured in single-solute systems. Sorption of the four compounds is affected by the complex mixture, with sorption decreases for all four compounds at high s:l ratio indicating competitive sorption. The effect on sorption of the individual compounds is not related to solubility or hydrophobicity of the compounds. Freundlich-type isotherms are observed for all compounds in the high s:l-ratio experiments, but for the most hydrophobic compounds isotherms are close to linear. The sorption of N-compounds and benzofuran is apparently influenced by cation exchange and dipole–dipole attraction to clay minerals. At high concentrations a dramatic increase in the sorption of the most strongly sorbing compounds is observed in the low s:l-ratio experiment. The dramatic increase in sorption appears to be a result of multimolecular layer sorption or condensation on surfaces in the clayey till at high surface density of organic compounds, and the data are fitted by BET (Brunauer, Emmet, and Teller) type 2 isotherms. The increase may or may not be induced by the presence of N-heterocyclic compounds sorbed by cation exchange and dipole–dipole attraction. The desorption of the compounds was studied for the low s:l ratio where multimolecular layer formation apparently had occurred. Partially irreversible sorption, hysteric Langmuir type desorption with isotherms of very high Kl coefficient, or behaviour reflecting dissolution of a condensed phase is observed.  相似文献   

11.
Huang XL  Zhang JZ 《Chemosphere》2011,85(8):1227-1232
Organophosphonate, characterized by the presence of a stable, covalent, carbon to phosphorus (C-P) bond, is a group of synthetic or biogenic organophosphorus compounds. The fate of these organic phosphorus compounds in the environment is not well studied. This study presents the first investigation on the sorption of phosphorus (P) in the presence of two model phosphonate compounds, 2-aminothylphosphonoic acid (2-AEP) and phosphonoformic acid (PFA), on marine carbonate sediments. In contrast to other organic P compounds, no significant inorganic phosphate exchange was observed in seawater. P was found to adsorb on the sediment only in the presence of PFA, not 2-AEP. This indicated that sorption of P from phosphonate on marine sediment was compound specific. Compared with inorganic phosphate sorption on the same sediments, P sorption from organic phosphorus is much less in the marine environment. Further study is needed to understand the potential role of the organophosphonate compounds in biogeochemical cycle of phosphorus in the environment.  相似文献   

12.
Environmental Science and Pollution Research - Adsorption-desorption behavior of ionic antibiotics in natural aquatic environment is complex, especially in coastal or estuary area where influencing...  相似文献   

13.
The current knowledge of the gas-phase reactions occurring in the troposphere for alkanes, alkenes, alkynes, oxygenates and aromatic hydrocarbons and their photooxidation products is reviewed,and areas of uncertainty identified.  相似文献   

14.
Environmental Science and Pollution Research - Recently, The literature has directed concern towards the consumption-based carbon emission (CCE), which is adjusted for trade. This study aims to...  相似文献   

15.
Mercury (Hg) is a global pollutant since its predominant atmospheric form, elemental Hg, reacts relatively slowly with the more abundant atmospheric oxidants. Comprehensive knowledge on the details of the atmospheric Hg cycle is still lacking, and in particular, there is some uncertainty regarding the atmospherically relevant reduction-oxidation reactions of mercury and its compounds. ECHMERIT is a global online chemical transport model, based on the ECHAM5 global circulation model, with a highly customisable chemistry mechanism designed to facilitate the investigation of both aqueous- and gas-phase atmospheric mercury chemistry. An improved version of the model which includes a new oceanic emission routine has been developed. Results of multiyear model simulations with full atmospheric chemistry have been used to examine the how changes to chemical mechanisms influence the model’s ability to reproduce measured Hg concentrations and deposition flux patterns. The results have also been compared to simple fixed-lifetime tracer simulations to constrain the possible range of atmospheric mercury redox rates. The model provides a new and unique picture of the global cycle of mercury, in that it is online and includes a full atmospheric chemistry module.  相似文献   

16.
Environmental Science and Pollution Research - The following work provides a perspective on the degradation of cytostatic pollutants through TiO2 heterogeneous photocatalysis. Cytostatic drugs are...  相似文献   

17.
Qualitative analysis of volatile organic compounds on biochar   总被引:6,自引:0,他引:6  
Qualitative identification of sorbed volatile organic compounds (VOCs) on biochar was conducted by headspace thermal desorption coupled to capillary gas chromatographic-mass spectrometry. VOCs may have a mechanistic role influencing plant and microbial responses to biochar amendments, since VOCs can directly inhibit/stimulate microbial and plant processes. Over 70 biochars encompassing a variety of parent feedstocks and manufacturing processes were evaluated and were observed to possess diverse sorbed VOC composition. There were over 140 individual chemical compounds thermally desorbed from some biochars, with hydrothermal carbonization (HTC) and fast pyrolysis biochars typically possessing the greatest number of sorbed volatiles. In contrast, gasification, thermal or chemical processed biochars, soil kiln mound, and open pit biochars possessed low to non-detectable levels of VOCs. Slow pyrolysis biochars were highly variable in terms of their sorbed VOC content. There were no clear feedstock dependencies to the sorbed VOC composition, suggesting a stronger linkage with biochar production conditions coupled to post-production handling and processing. Lower pyrolytic temperatures (?350 °C) produced biochars with sorbed VOCs consisting of short carbon chain aldehydes, furans and ketones; elevated temperature biochars (>350 °C) typically were dominated by sorbed aromatic compounds and longer carbon chain hydrocarbons. The presence of oxygen during pyrolysis also reduced sorbed VOCs. These compositional results suggest that sorbed VOCs are highly variable and that their chemical dissimilarity could play a role in the wide variety of plant and soil microbial responses to biochar soil amendment noted in the literature. This variability in VOC composition may argue for VOC characterization before land application to predict possible agroecosystem effects.  相似文献   

18.
Effects of airborne volatile organic compounds on plants   总被引:4,自引:0,他引:4  
Routine measurements of volatile organic compounds (VOCs) in air have shown that average concentrations are very much smaller than those used in laboratory experiments designed to study the effects of VOCs on plants. However, maximum hourly concentrations of some VOCs can be 100 times larger than the average, even in rural air. Experimental studies have rarely extended for longer than a few days, so there is little information on potential long-term effects of exposure to small concentrations. This review considers the available evidence for long-term effects, based on laboratory and field data. Previous reviews of the literature from Germany and the USA are cited, prior to an assessment of the effects of individual VOCs. Although hydrocarbons from vehicle exhausts have been implicated in the observed effects on roadside vegetation, the evidence suggests that it is the nitrogen oxides in the exhaust gases that are mostly responsible. There is evidence that aromatic hydrocarbons can be metabolised in plants, although the fate of the metabolites is not known. There is a large literature on the effects of ethylene, because of its role as a plant hormone. Effects have been reported in the field, in response to industrial emissions, and dose-response experiments over several weeks in laboratory studies have clearly identified the potential for effects at ambient concentrations. The main responses are morphological (e.g. epinasty), which may be reversible, and on the development of flowers and fruit. Effects on seed production may be positive or negative, depending on the exposure concentration. Chlorinated hydrocarbons have been identified as potentially harmful to vegetation, but only one long-term experiment has studied dose-response relationships. As for ethylene, the most sensitive indication of effect was on seed production, although long-term accumulation of trichloroacetic acid in tissue may also be a problem. There is little evidence of the direct effects of oxygenated hydrocarbons on plants. Plants are a significant emission source of short-chain alcohols, aldehydes and ketones. Peroxyacetyl nitrate (PAN) has a well-documented history as damaging to vegetation. There have been few long-term experimental studies despite the field evidence for damaging effects. Early studies in California have been followed by more recent data from east Asia, but there is still a dearth of information on the potential for effects of PAN and related peroxyacyl nitrates on vegetation typical of regions around tropical and sub-tropical cities where PAN pollution is increasingly important. The lack of long-term measurements, coupled with the available evidence that effects are not linearly related to 'dose' measured as the product of exposure concentration and time, means that the possibility of adverse effects of VOCs on vegetation cannot be safely rejected, particularly in urban and industrial areas. Although reproductive processes (flowering, seed production) appear to be most sensitive, there have been no experimental studies on subsequent seed viability and the consequences at the ecosystem level of changes to plant phenology. The potential for VOC metabolites to accumulate in plant tissue has been demonstrated, but any subsequent effects on herbivores and phytophagous insects have yet to be investigated.  相似文献   

19.
Environmental Science and Pollution Research - Anaerobic digestion (AD) is the most widely used technology for organic matter treatment. However, multiple types of research have reported on...  相似文献   

20.
Tremblay L  Kohl SD  Rice JA  Gagné JP 《Chemosphere》2005,58(11):302-1620
The impact of the lipid fraction of natural geosorbents on the sorption of a polycyclic aromatic hydrocarbon was assessed using several experiments. In the first set of experiments phenanthrene was sorbed on a coastal sediment as well as on its humin and humic acid fractions before and after lipid extraction. Before lipid extraction, sorption shows dominantly partitioning characteristics. However, the extraction of lipids from sediment and humin drastically increases, by up to one order of magnitude, their sorption affinity for phenanthrene at low sorbate concentrations, resulting in increased isotherm nonlinearity. This effect is less pronounced for humic acids. One mechanism proposed for the increasing sorption is that lipids, despite their very low relative abundance in the sediments, can compete with phenanthrene for specific high affinity sorption sites (e.g., matrix pores and adsorption sites). This competition is not surprising considering the similar hydrophobic nature of lipids and phenanthrene. Lipids, or any non-polar molecules, could also act like plasticizers by swelling rigid domains and disrupting high affinity sites. In both cases, the removal of lipids (and extraction solvents) makes those sites available for phenanthrene. These provide alternative explanations to the previously proposed “solvent conditioning effect” believed to occur when geosorbents are treated with non-polar solvents modifying the matrix structure, an effect yet to be proven at molecular scale. To further investigate the impact of lipids on sorption, other independent experiments were performed. In a second experiment, re-addition of lipids to the extracted sediment restored the sorption isotherm linearity observed in the native material supporting the absence of irreversible extraction artifacts. However, high addition of lipids (i.e., after saturation of high affinity sites) seems to also enlarge the low affinity partitioning domain. These results are consistent with dual-mode, hole-filling, sorption models involving diffusion. In the final set of experiments, solid-state 19F-NMR using F-labeled lipids sorbed onto the sediments confirmed that lipids may be in different domains (mobile or rigid) that interact or not with phenanthrene. The possible effects of lipid removal on sorption have been overlooked and should be considered when geosorbents are pretreated.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号