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 562 毫秒
1.
CharacteristicsofchangeofhumicsubstanceinsoilindegradedgraslandsShengXuebinResearchCenterforEcoEnvironmentalSciences,Chinese...  相似文献   

2.
Biodegradation of mixture of VOC''''s in a biofilter   总被引:3,自引:0,他引:3  
IntroductionDeterioratingatmosphericairqualityhasresultinginmorestringentregulationsarebeingenforcedtocontrolairpollutants .Volatileorganiccompounds(VOCs)areamongthenewclassofaircontaminantsgeneratedfromavarietyofindustrialsources .Effortstocontroltheemis…  相似文献   

3.
1 IncreasingenvironmentalproblemscallfortechnologicalsolutionsWiththerapideconomicgrowthinthepasttwodecades,allthemajorenvironmentalproblemsofworldwideconcernhaveappearedinChinainonewayoranother.Theyaremainlyreflectedinsoilerosion,desertification,bi…  相似文献   

4.
Continuous measurements of the methane flux from rice fields in Hangzhou,eastern China,arid Leshan,Sichuan Province,were carried out for 3 years.The results show that the methane flux from rice fields has a strong diurnal variation which may be explained by the soil temperature effects and rice plant growing activities,and that the day-mean flux has a large seasonal variation which may be related to soil temperature and the availability of organic substrate in the soil.An overall sources of methane for China are estimated while the rice fields are major sources,and the sewage tmatment is an important source of methane in China that has not been measure.Sewage in China is often treated in cesspools,which are similar to the biogas pits.However,no methane is recovered from such cesspools.We estimate that the total flux of methane from such sources may be of the oidcr of 10 Tg/a.The total emissions of methane from sources in China are estmmted to be about 40±lOTg/a.  相似文献   

5.
EnvironmentalgeochemicalfeaturesofarsenicinsoilinChinaWengHuanxin,LiuYunfengDepartmentofEarthSciences,ZhejiangUniversity,Hang...  相似文献   

6.
The impacts of petroleum contamination on the litter decomposition of shrub–grass land would directly influence nutrient cycling, and the stability and function of ecosystem. Ten common shrub and grass species from Yujiaping oil deposits were studied. Litters from these species were placed into litterbags and buried in petroleum-contaminated soil with 3 levels of contamination (slight, moderate and serious pollution with petroleum concentrations of 15, 30 and 45 g/kg, respectively). A decomposition experiment was then conducted in the lab to investigate the impacts of petroleum contamination on litter decomposition rates. Slight pollution did not inhibit the decomposition of any litters and significantly promoted the litter decomposition of Hippophae rhamnoides, Caragana korshinskii, Amorpha fruticosa, Ziziphus jujuba var. spinosa, Periploca sepium, Medicago sativa and Bothriochloa ischaemum. Moderate pollution significantly inhibited litter decomposition of M. sativa, Coronilla varia, Artemisia vestita and Trrifolium repens and significantly promoted the litter decomposition of C. korshinskii, Z. jujuba var. spinosa and P. sepium. Serious pollution significantly inhibited the litter decomposition of H. rhamnoides, A. fruticosa, B. ischaemum and A. vestita and significantly promoted the litter decomposition of Z. jujuba var. spinosa, P. sepium and M. sativa. In addition, the impacts of petroleum contamination did not exhibit a uniform increase or decrease as petroleum concentration increased. Inhibitory effects of petroleum on litter decomposition may hinder the substance cycling and result in the degradation of plant communities in contaminated areas.  相似文献   

7.
This study investigated the electrokinetic(EK)behavior of multiple chlorobenzenes,including 1,2,3,4-tetrachlorobenzene(TeCB), 1,2,4,5-tetrachlorobenzene(i-TeCB),and 1,2,3-trichlorobenzene(TCB)in contaminated clayed soils.The effect ofβ-cyclodextrin(β- CD)on the EK removal of the chlorobenzenes was studied.The largest removal was obtained when Na_2CO_3/NaHCO_3 buffer was used as anodic purging solution withoutβ-CD.The removal efficiencies were related to the aqueous solubilities of chlorobenzenes. With the same cumulative electroosmotic flow,greater solubility led to higher removal efficiency.The addition ofβ-CD inhibited the EK removal efficiency of all chlorobenzenes.The inhibition increased with the increase ofβ-CD concentration.With the sameβ-CD concentration,the inhibition increased with the rise of electric potential.It was found that the inclusion compounds betweenβ-CD and chlorobenzenzes were less soluble than chlorobenzenes.The formation of the less soluble inclusion compounds reduced the aqueous solubility of chlorobenzenes and led to the partial immobilization of the chlorobenzenes that desorbed from soil.It was feasible to use the EK technology to remove ehlorobenzenes in contaminated soils using water as the anodic flushing solution.The addition ofβ-CD was not recommended for the EK removal of chlorobenzenes.  相似文献   

8.
The crystal growth of hydroxyapatite (HAP) seeds in presence of the abnormal collagen secreted by the chondrocyte grown in media containing free radical sources or fulvic acid and the type II collagen (pig cartilage) damaged by · OH and fulvic acid(FA) from potable water in endemic region of Kaschin-Beck disease (KBD) was studied. The results showed that in the former case, the abnormal collagen rich in type I collagen promoted mineralization in contrast with the type n collagen. The oxidatively damaged type II collagen became less inhibitive or even promotive. In all cases, the reaction followed a second order kinetics. The powder X-diffraction analysis and SEM observation indicated that the damaged type II collagen lowers the crystalinity in the beginning and made the final crystal more agglomerated. All the results showed that the abnormal and the damaged cartilage matrix affected the bimineralization and was likely to have played an important role in the development of KBD.  相似文献   

9.
IntroductionHealthhazardsfrommercuryintheenvironmenthavecausedrestrictionsintheuseofmercuryandastrictercontrolofthereleaseofmercuryfromindustrialandotheruses.Butatthesametimethesesourcesofmercuryhavebeensubjectedtoregulation ,twonewsourceshaveappeared …  相似文献   

10.
The degradation of pesticide 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(CCU)in water and its accumulation and metabolism in fish were studied using HPLC method.The results of acute toxicity of both CCU and its naetabolites were also reported.The research demonstrated that CCU degraded quickly in aerobic aquatic environment and primary metabolites of CCU were 4-chlorophenyl urea and orthochlorobenzoic acid.Microorganisms play an important role for the degradation of CCU in water.Both the parents compound and its metabolites were not lethal to fish in tested concentration.The accumulation of CCU in fish was sunilar to that of dillubenzuron.The esterase in fish liver which could metabolized CCU was identified.The primary enzymatic degradation products of CCU is the same as that in water.  相似文献   

11.
Gas chromatography with ambient temperature injection and frozen-trapped techniques was used to determine the atmospheric concentrations of halocarbons over Beijing. Halogenated compounds such as CFC-11, CFC-12, CHCl_3, CCl_4, CH_3CCl_3, CHCl =CCl_2, and CCl_2=CCl_2 were measured and their concentrations are 109±8, 234±13, 47±22, 97±24, 88±29, 11±1 and 17±3 (pptv), respectively.  相似文献   

12.
1 Determinationoftotalmercuryandspeciationofmercurycompoundsinatmosphere1.1 DeterminationoftotalmercuryAsamplingtrainconsistingofafiltertoretain particulatephasemercuryfollowedbyanabsorbenttrapwhichretainstotalgaseousmercuryisusedfordeterminationoftota…  相似文献   

13.
Applicationofface-graphinheavymetalpollutionassessmentinriversedimentJiaZhenbang;ZhaoZhijie(GeographyDepartment,PekingUnivers...  相似文献   

14.
A study has been made on elements organic constituents, TSP, SO2,NO2 of atmospheric pollutants in Beijing. 17 elements, and some PAHs, e. g. B(a)P, B(b, j, k)P, and B(g, h, i)P, in airborne particles by X-ray fluorescence spectroscopy and HPLC, GC/MS, have been determined respectively. It has been shown that the elements Pb, Zn, S and Cu were more enriched in fine particles and different valence states of sulfur at various sites. It was found that the concentrations of S6+ and S2-were more than 85% and less than 15% of the total sulfur respectively. Concentrations of major PAHs and sulfur-containing compounds increased in winter and in urban area. High values for Pb and Zn in city, Fe and Mn at industrial area and Cu, Al rural sites were obtained respectively. This implies the functions of different elemental sources of various sites. Thus, elements can be from distingushed anthropogenic and natural sources.The main contribution of SO2 was found of to have same seasonal variation as the anthropogenic el  相似文献   

15.
This article described the change of technological paradigm from environmentally unfriendly technology to environmentally sound technology(EST),and reported results from the investigation made in 1993-1995 of how China's small-medium enterprises(SMEs)have been innovating technology in response to environmental pressures and tried to identify factors affecting China' SMEs to innovate more environmentally sound products and processes.  相似文献   

16.
IntroductionTheradionuclidesinlow levelradioactiveliquidwaste (LLW)fromcoastalnuclearfacilitiesornuclearpowerplantswillbediluted ,diffusedandtransportedinthecoastarea .Andtheywillalsodepositinthesediment.Howtoestimatetheeffectofdepositradionuclidesisaver…  相似文献   

17.
The progress of biomonitoring on water pollution in recent years in China has been summarized in this paper.  相似文献   

18.
lectrochemicalstudyofsulfidesolutioninthepresenceofsurfactantsYiQingfengDepartmentofChemicalEnginering,XiangtanPolytechnicU...  相似文献   

19.
On Peak Namjagbarwa (Tibet Plateau), Lushan Mountain (Province Jiangxi), Flower Mountain and Shangdianzi (Beijing, near Great Wall) aerosol samples have been collected by cascade samplers. For comparison aerosol samples from Beijing City, Pacific Ocean and South Pole also have been collected. Samples were analyzed with PIXE or XFA instruments. Factor analysis and enrichment factor calculation were performed to process the data.  相似文献   

20.
1IntroductionThechemicalspeciationofheavymetalsintheaquaticenvironmenthasdetermininginfluenceontheirtransport,reactionsandbio...  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