Journal of Environmental Sciences - Volume 12, issue 3

Authors: Peng, Chang-hui | Apps, Michael J.

Article Type: Research Article

Abstract: It has been argued that increased soil respiration would become a major atmospheric source of CO_2 in the event of global warming. The simple statistical models were developed based on a georeferenced database with 0.5° × 0.5° longitude/latitude resolution to simulate global soil-CO_2 fluxes, to investigate climatic effects on these fluxes using sensitivity experiments, and to assess possible responses of soil-CO_2 fluxes to various climate change scenarios. The statistical models yield a value of 69 …PgC/a of global soil CO_2 fluxes for current condition. Sensitivity experiments confirm that the fluxes are responsive to changes in temperature,precipitation and actual evapotranspiration, but increases in temperature and actual evapotranspiration affect soil-CO_2 fluxes more than increases in precipitation. Using climatic change projections from four global circulation models, each corresponding to an equilibrium doubling of CO_2, it can be found that the largest increases in soil-CO_2 fluxes were associated with the boreal and tundra regions. The globally averaged soil-CO_2 fluxes were estimated to increase by about 35% above current values, providing a positive feedback to the greenhouse effect. Show more

Keywords: climatic variable, sensitivity experiment, soil respiration, statistical model

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 257-265, 2000

Authors: Li, Chao-min | Hou, Jian | Yu, Yong | Hou, Hui-qi

Article Type: Research Article

Abstract: In this paper the mechanism and kinetic of ozone decomposition under the irradiation of 253.7 nm UV-light were studied.The quantum yield of the ozone depletion in the presence of methyl bromide is further determined and a reaction model is provided to explain the experimental fact.

Keywords: methyl bromide, ozone, UV

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 266-269, 2000

Authors: Zhang, Shi-qiu

Article Type: Research Article

Abstract: This paper discusses the specific features of the energy in China, and addresses those key challenges in China is that the coexist of (1) higher total energy production and lower per capita level; (2) lower per capita energy resources level with unrational energy consumption structure; (3) lower energy utilization efficiency and higher energy conservation potential; and (4) unequal distribution of energy resources. It reviews the key environmental problems related to the feature of energy production and …consumption. Based on the analysis, the author furthers addresses the policy and actions needed. Show more

Keywords: energy, energy production, energy consumption, environment, policy

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 270-274, 2000

Authors: He, Bin | Jiang, Gui-bin

Article Type: Research Article

Abstract: A convenient hydride derivatization procedure of methyl-and ethylmercury chlorides to volatile hydrides was reported. In sealed vials methylmercury and ethylmercury compounds in acidic aqueous solutions were converted into their volatile forms by the reaction with potassium tetrahydroborate (KBH_4) and elvolved to the headspace of the vials. The gaseous analytes in the headspace were extracted and concentrated by solid phase microextraction (SPME) and injected into gas chromatography (GC) for separation and identified by …mass selective detector (MS). Show more

Keywords: hydride derivatization, methyl- and ethylmercury, gas chromatography, mass selective detector

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 275-278, 2000

Authors: Hong, Lin | Takase, Keiji | Sato, Koichi

Article Type: Research Article

Abstract: In this study, the characteristics of the long term discharge of a Terraced Paddy Field Catchment are studied. 2 Kind of Tank Models are proposed and used to simulate the discharge of the catchment. The characteristics of the model simulations of the discharge of the catchment are analyzed and compared with those of a forest catchment.

Keywords: long term discharge, model simulation, terraced paddy field catchment

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 279-285, 2000

Authors: Ghosh, Debidas | Ghosh, Sampa | Chattopadhyay, Sandip | Debnath, Jogen

Article Type: Research Article

Abstract: Changes in the activities of &b.Delta;^5-3ß-hydroysteroid dehydrogenase (HSD) in testis and adrenal gland, 17ß-hydroxysteroid dehydrogenase in testis, acid and alkaline phosphatase in testis, prostate and seminal vesicle were observed in noise exposed mature rats at the intensity of 85 dB for 8 h/day for 45 days. The results indicated that noise exposed group showed a significant diminution in the activities of androgenic key enzymes &b.Delta;^5-3ß and 17ß-HSD, acid phosphatase in testis, prostate …and seminal vesicle. There was a significant elevation in the activities of adrenal &b.Delta;^5-3ß-HSD, alkaline phosphatase in testis and other accessory sex organ in noise exposed group. Gonadosomatic, prostatosomatic and seminal vesiculo-somatic indexes were decreased significantly in noise exposed group. Therefore, it is evident that noise exposure at 85dB exerts a deleterious effect on testicular and adrenocortical activities. Show more

Keywords: noise, hydroxysteroid dehydrogenase, acid phosphatase, alkaline phosphatase, sex organs, adrenal cortex

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 286-289, 2000

Authors: Lei, Le-cheng | Sun, Yuan

Article Type: Research Article

Abstract: This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two-liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290°C, and the partial pressure of oxygen ranged from 0. 375 to 2.25 MPa. Variations in pH, COD_Cr and TOD content were monitored during each experiment and used to assess the extent of conversion …of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90 % COD_Cr reduction and 80 % TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre-treatment methods due to improvement of the BOD_5/COD_Cr ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage. Show more

Keywords: wet air oxidation, wastewater treatment, textile wastewater

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 290-295, 2000

Authors: Essien, J. P. | Udosen, E. D.

Article Type: Research Article

Abstract: The distribution of actinomycetes in oil contaminated sandy loam ultisols of the Niger Delta region of Nigeria was studied to aid in understanding the effect of hydrocarbons on indigenous microbial population in tropical soils. The average total counts of actinomycetes in all the oil samples analysed was 10³ cfu/g. Higher counts of actinomycetes were observed during the dry season than during the wet season. The counts of hydrocarbonoclastic actinomycetes correlated positively with the total count of …actinomycetes.The actinomycetes were generally restricted to the top soil (0-10 cm soil depth) although a seemingly deeper (down to 40 cm soil depth) distribution was noticed in the dry season. The isolates included oil degrading species of Actinoplanes, Norcadia,Streptomyces and Streptosporangium. Their high oil utilization ability indicates their positive potential and role in the bioremediation of oil-spilled soils. Show more

Keywords: actinomycetes, oil contaminated ultisols

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 296-302, 2000

Authors: Ye, Chang-ming | Gong, Ai-jun | Lei, Zhi-fang | Wang, Xing-jun | Zheng, He-hui

Article Type: Research Article

Abstract: A simulation experiment on vertical transport of herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high-performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil …decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3 % is out through leaching water, 1% is methanol extractable residues in soil, 46 % is methanol nonextractable residues in soil, and 52 % is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history. Show more

Keywords: soil, lysimeter, atrazine, vertical transport, sorption, distribution

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 303-309, 2000

Authors: Wen, Bin | He, Min-yuan

Article Type: Research Article

Abstract: The fluid catalytic cracking(FCC) is the principal gasoline-producing process in the refinery. Considerable amounts of harmful sulfur oxides and nitrogen oxides (SO_x and NO_x ) are generated with the FCC operation. Impacted by strengthening environmental regulations and the current global emphasis on environmental protection and pollution abatement, refiners have been meaning to look for effective ways to control and reduce SO_x and NO_x emissions. FCC DeSO_x and DeNO_x additives is the most promising measure. …The present paper reviews the developments in FCC DeSO_x and DeNO_x additive technology based on the respective authors' works, the future directions of the technology are also discussed. Show more

Keywords: FCC, NO_x, SO_x, DeSO_x additive, DeNO_x additive

Citation: Journal of Environmental Sciences, vol. 12, no. 3, pp. 310-318, 2000