Journal of Environmental Sciences - Volume 17, issue 4

Authors: SONG, Yu-fang | GONG, Ping | ZHOU, Qi-xing | SUN, Tie-heng

Article Type: Research Article

Abstract: Seedling emergence tests were conducted in a meadow brown soil using five plant species (i. e., Chinese cabbage, green onion, tomato, turnip and wheat) to determine the phytotoxicity of phenanthrene, pyrene and their mixtures. The soil was amended with up to 1000 mg/kg soil of phenanthrene or 600 mg/kg soil of pyrene. Seedling emergence and root growth were measured. The results indicated that root elongation was more sensitive than seedling emergence. Root length decreased with increasing …phenanthrene or pyrene concentrations (p ⩽ 0.05). Phenanthrene was more phytotoxic than pyrene. The lowest observable adverse effect concentration (LOAEC) was 10 mg/kg for phenanthrene when tested with green onion, and 50 mg/kg for pyrene when tested with wheat. Among the five species,wheat was found to be the most sensitive. When amended jointly at or below their respective LOAEC, phenanthrene and pyrene produced a synergistic toxic effect. Show more

Keywords: phenanthrene, pyrene, phytotoxicity, seedling emergence, root length, combined effects, soil

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 580-583, 2005

Authors: SUN, Yue | LI, Xiao-tao | XU, Chao | CHEN, Jin-long | LI, Ai-min | ZHANG, Quan-xing

Article Type: Research Article

Abstract: Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1, AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of …the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition, thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy. Show more

Keywords: hypercrosslinked polymer, catechol, adsorption, thermodynamics, kinetics

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 584-588, 2005

Authors: LIN, Yan | HE, Yi-liang | KONG, Hai-nan | LIU, Bin-bin | LI, Yan | INAMON, Yuhei

Article Type: Research Article

Abstract: The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. Continuous tests via a membrane bioreactor (MBR) were operated under the controlled conditions to proliferate the nitrifiers. Heterotrophic nitrifying bacteria were isolated from the system in which the efficiency of total nitrogen (TN) removal was up to 80%. Since no autotrophic ammonium and nitrite oxidizers could be detected by fluorescence in situ hybridization (FISH), oxidized-N production …was unlikely to be catalyzed by autotrophic nitrifiers during the heterotrophic nitrifiers' isolation in this study. The batch test results indicate that the isolated heterotrophic bacteria were able to nitrify. After 3 weeks incubation, the efficiencies of the COD removal by the three isolated bacterial strains B1, B2, and B3 were 52.6%, 71.7%, and 77.7%, respectively. The efficiencies of the TN removal by B1, B2, and B3 were 35.6%, 61.2% and 68.7%, respectively. Show more

Keywords: membrane bioreactor (MBR), simultaneous nitrification and denitrification (SND), heterotrophic nitrification, aerobic denitrification

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 589-592, 2005

Authors: WANG, Xue-dong | ZHOU, Su-mei | WANG, Hui-li | FAN, De-fang

Article Type: Research Article

Abstract: The degradation of imazapyr in non-sterile and sterile soils from four sampling sites in Zhejiang, China was studied. The results showed that the half-lives of imazapyr in non-sterile soils were in the range of 30 to 45 d, while 81 to 133 d in sterile (by autoclaving) soils. It means the rate constants of imazapyr under non-sterile conditions were 2.3–4.4 times faster than that under sterile (by autoclaving) conditions, evidently indicating that the indigenous microorganisms in …soil play an important role in the degradation of imazapyr. The different sterilization methods could result in different degradation rates of imazapyr. The heat of sterilization of soil largely decreased the degradation. However, the sterile treatment of soil by sodium azide had a different effect from that by autoclaving. Further more, the mechanism was also discussed. Biodegradation in four non-sterile soils accounted for 62% to 78% of imazapyr degradation. In contrast, less than 39% of imazapyr degradation was associated with chemical mechanisms. Therefore, the degradation mechanism was predominantly involved in biology including organisms and microorganisms in soil. Two imazapyr-degrading bacterial strains were isolated in enrichment culture technique and they were identified as Pseudomonas fluorescenes biotype II (ZJX-5) and Bacillus cereus (ZJX-9), respectively. When added at a concentration of 50 μg/g in mineral salts medium (MSM), ZJX-5 and ZJX-9 could degrade 81% and 87% imazapyr after 48 h of incubation. For the treatment of incorporation of ZJX-5 or ZJX-9 into soil, the degradation rate enhanced 3–4 fold faster than that for control samples, which showed an important value in quick decontamination of imazapyr in soil. Show more

Keywords: biodegradation, imazapyr, sterile soil, non-sterile soil, imazapyr-degrading bacteria

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 593-597, 2005

Authors: CHEN, Bing | YANG, Chun | GOH, Ngoh Khang

Article Type: Research Article

Abstract: The direct photolysis of nitrobenzene and nitrophenols in aqueous solutions irradiated by polychromatic light were investigated. Several aromatic intermediates were identified as three nitrophenol isomers, nitrohydroquinone, nitrosobenzene, nitrocatechol, catechol and phenol. Nitrite and nitrate ions were also detected in the irradiated solution indicating direct photolysis of nitrobenzene or nitrophenols. The degradation of nitrobenzene and nitrophenols and the formation of three nitrophenol isomers were observed to follow zero-order kinetics. The quantum yields for …nitrobenzene and nitrophenols removal are about 10^{-3} and 10^{-3} –10^{-4} respectively. The mechanism for nitrobenzene degradation was suggested to follow mainly nitro-nitrite intramolecular arrangement. Show more

Keywords: photodegradation, photolysis, nitrobenzene, nitrophenols

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 598-604, 2005

Authors: CAI, Heng-jiang | TANG, Xue-xi | ZHANG, Pei-yu | DONG, Dong | QU, Liang

Article Type: Research Article

Abstract: Enhanced UV-B (280–320 nm) radiation resulting from ozone depletion is one of global environmental problems. Not only marine organisms but also marine ecosystems can be affected by enhanced UV-B radiation. The effects of UV-B radiation on interaction of macro-algae and micro-algae were investigated using Ulva pertusa Kjellman and Alexandrium tamarense as the materials in this study. The results demonstrated that UV-B radiation could inhibit the growth of Ulva pertusa and Alexandrium tamarense when they were …both mono-cultured, and the growth inhibition of algae was more significant with increasing doses of UV-B radiation. Alexandrium tamarense could inhibit the growth of Ulva pertusa in mixed culture, and the growth inhibition was more significant when increasing the initial cell density. However, Ulva pertusa could inhibit the growth of Alexandriurm tamarense in early phase and stimulate the growth in latter phase when they were grown in mixed culture. Lower initial cell density (10^2 cell/mi) of Alexandriurm tamarense could inhibit the growth of Ulva pertusa under UV-B radiation treatment, however, with the initial cell density increasing (10^3 and 10^4 cell/ml), the growth of Ulva pertusa was stimulated under lower dose of UV-B radiation and inhibited under higher dose of UV-B radiation by Alexandrium tamarense. Compared with that in mixed culture, Ulva pertusa showed more positive inhibition to the growth of Alexandrium tamarense under UV-B radiation treatment. Show more

Keywords: UV-B radiation, mono-culture, mixed culture, pertusa, Alexandrium tamarense, growth

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 605-610, 2005

Authors: YU, Shui-li | LIU, Ya-nan | JING, Guo-lin | ZHAO, Bing-jie | GUO, Si-yuan

Article Type: Research Article

Abstract: To investigate the microbial communities of microorganisms cultivated under different carbon sources, three sequencing batch reactors were operated. They were supplied with sewage, glucose and sodium acetate as carbon sources respectively and showed high phosphorus removal performance. The results of denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction-amplified (PCR) 16S rDNA fragments demonstrated that β-protebacteria, Actinomyces sp. and γ-protebacteria only exited in 1 # reactor. The microbiological diversity of 1 # …reactor exceeded the other two reactors. Flavobacterium, Bacillales, Actinomyces, Actinobacteridae and uncultured bacteria (AF527584, AF502204, AY592749, AB076862, AJ619051, AF495454 and AY133070) could be detected in the biological phosphorus removal reactors. Show more

Keywords: 16S rDNA, carbon source, biological phosphorus removal, PCR-DGGE

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 611-614, 2005

Authors: ZHENG, Yi-hua | HUA, Tse-chao | XU, Fei

Article Type: Research Article

Abstract: A novel thermal biosensor based on enzyme reaction for pesticides detection has been developed. This biosensor is a flow injection analysis system and consists of two channels with enzyme reaction column and identical reference column, which is set for eliminating the unspecific heat. The enzyme reaction takes place in the enzyme reaction column at a constant temperature (40°C) realized by a thermoelectric thermostat. Thermosensor based on the thermoelectric module containing 127 serial BiTe-thermocouples is used to …monitor the temperature difference between two effluents from enzyme reaction column and reference column. The ability of this biosensor to detect pesticides is demonstrated by the decreased degree of the hydrolytic heat in two types of thermosensor mode. The hydrolytic reaction is inhibited by 36% at 1 mg/L DDVP and 50% at 10 mg/L DDVP when cell-typed thermosensor is used. The percent inhibition is 30% at 1 mg/L DDVP and 42% at 10 mg/L DDVP in tube-typed thermosensor mode. The detection for real sample shows that this biosensor can be used for detection of organophosphate pesticides residue. Show more

Keywords: thermal biosensor, pesticides residue, thermoelectric module, flow injection analysis (FIA)

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 615-619, 2005

Authors: WANG, Hai-lei | LI, Zong-yi | GUO, Wei-yun | WANG, Zhen-yu | PAN, Feng

Article Type: Research Article

Abstract: Since the ability to degrade lignin with one kind of white-rot fungi or bacteria was very limited, superior mixed flora's ability to degrade lignin was investigated by an orthogonal experiment in this paper. The results showed that superior mixed flora reinforced the ability to degrade lignin, the degradation rates of both sample 9 and 10 were beyond 80% on the day 9. The cooperation between lignin peroxidase (LiP), Mn-dependent peroxidase (MnP) and laccase (Lac) for lignin …degradation was also studied. By examining the activities of three enzymes produced by superior mixed flora, it was found that Lac was a key enzyme in the process of biological degradation of lignin but Lip was not; the enzyme activity ratios of Lac/MnP and Lac/LiP were significantly correlative with the degradation rate of lignin at the 0.01 level; and the ratio of MnP/LiP was an important factor affecting the degradation rate of lignin. Show more

Keywords: white-rot fungi, lignin peroxidase, Mn-dependent peroxidase

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 620-622, 2005

Authors: YANG, Shao-xia | FENG, Yu-jie | WAN, Jia-feng | LIN, Qing-ying | ZHU, Wan-peng | JIANG, Zhan-peng

Article Type: Research Article

Abstract: The pretreatment technology of wet air oxidation (WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH_4^+ concentration, and the ratio of BOD_5 /COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO_2 /Al_2 O_3 and RuO_2 -CeO_2 /Al_2 O_3 …catalysts, was carried out at degradation temperature of 200°C and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50.2% and 55.0%, COD removals were 40.0% and 46.0%, and the ratio of BOD_5 /COD was increased to 0.49 and 0.54 with RuO_2 /Al_2 O_3 and RuO_2 -CeO_2 /Al_2 O_3 catalysts in catylytic wet air oxidation (CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD_5 /COD was increased to 0.45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were effectively controlled and the reaction time was obviously shortened with WAO·HO_2 · may promote organic compounds oxidized in WAO of the apramycin wastewater. The addition of CeO_2 could promote the activity and stability of RuO_2 /Al_2 O__3 in WAO of apramycin wastewater. Show more

Keywords: catalytic wet air oxidation (CWAO), metal catalyst, antibiotic production wastewater, apramycin wastewater

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 623-626, 2005

Authors: YU, Gang | YU, Qi | JIANG, Yan-long | ZENG, Ke-si

Article Type: Research Article

Abstract: As a new type of NO removal system, NO reduction in N_2 -NO plasma was applied to solve the difficulties in the traditional methods, such as higher energy-consumption, larger equipment size and high cost, and so on. Using the experimental NO reduction system with single-pair electrode tip discharge structure, the NO reduction characteristics of N_2 -NO system were revealed to guide the engineering practice; the results of NO reduction with single-pair electrode tip discharge …plasma also have the same instructive meaning to the NO reduction with multi-pair electrode tip discharge plasma. The amount of both active N atom and NO removal rate increased with the distance I_g increasing between the two electrode tips and then dropped when the distance exceeded a certain value. The NO removal rate increased while the voltage between two electrode tips or the resident time of gas flow increased. The distance is a key geometrical variable factor that can determine the intensity of electric field between two electrode tips and the resident time of gas. In this paper, the effects of the dielectric features on NO reduction using dielectric-barrier discharge plasma system were also studied. The results of NO removal rate with different dielectrics such as Al_2 O_3 , CaO, MgO and glass showed that the electric field intensity is different with different dielectric, because it brings different energy to particles in discharge room and thus it causes different NO removal rate. Show more

Keywords: NO reduction, plasma, characteristic, single-pair electrode tip discharge, dielectric-barrier discharge

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 627-630, 2005

Authors: PARVEEN, Sultana | KOHGUCHI, Testuyuki | BISWAS, Moloy | NAKAGOSHI, Nobukazu

Article Type: Research Article

Abstract: This study was conducted to investigate the dissipation pattern and runoff of herbicides to the river basin from the paddy fields. Pesticide paddy field model (PADDY) was applied to predict herbicide concentration in paddy fields. A field study was conducted in a paddy farm of Higashi Hiroshima City, Hiroshima Prefecture, Japan in the year of 2003 paddy season. The herbicides were mefenacet, thiobencarb, and bensulfuron methyl. The sample water was analyzed by using gas chromatography and …HPLC after solid phase extraction. Predicted dissipation rate of thiobencarb in paddy water was higher (DT_{50} = 4.36) than that measured, with a lower k value (−0.069). Two weeks after application no thiobencarb was detectedin the drainage channel and down stream. In the down stream, thiobencarb was detected until 3 d after application, with a range of 0.02% to 0.08% of applied herbicide. The predicted dissipation rate (k) and half-life (DT_{50} ) of mefenacet was not significantly different from that of measured. In the drainage channel, upstream and downstream mefenacet was found during the whole study period. In downstream, the maximum concentration of mefenacet was present 0.61% of applied in the paddy field on 3DAH. The dissipation rate (k) of BSM varied from −0.0860 to −0.1059 to with half-life (DT_{50} ) 3.5 and 2.84 d. In upstream water, no BSM was detected except trace amounts (0.01 μg/L) at 3 d after application. However, in the drainage channel 8%, 6% and 1.58% of applied BSM was present at 0, 1 and 3 d after application respectively. In the down stream, the highest concentration was 1.06%, shortly after application. Show more

Keywords: paddy field, pesticide paddy field model (PADDY), herbicide, dissipation, runoff

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 631-636, 2005

Authors: CHEN, Cheng-li | LIAO, Min | HUANG, Chang-yong

Article Type: Research Article

Abstract: Some enzymatic activities were determined in the areas polluted by tailings from Tiantai Pb-Zn-Ag Mine in Zhejiang Province of China. The results indicated the soil enzymatic activities decreased significantly with increase of concentrations of heavy metals or the distance away from mining tailing center, especially dehydrogenase and urease activities. Multivariate regression analysis between heavy metal contents and soil enzymatic activities indicated that single dehydrogenase activity was very significantly correlated to combined effect …of soil heavy metals in mine area. Moreover, single urease, protease and acid phosphatase activities were significantly related to the combined effect of heavy metals. The results suggest it is feasible to use soil enzymatic activities to indicate the pollution situation by combined heavy metals in the soil of mine area. Show more

Keywords: heavy metal, Pb-Zn-Ag mine tailing, soil enzyme

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 637-640, 2005

Authors: SONG, Young-bae

Article Type: Research Article

Abstract: Five new towns have been developed around the Seoul metropolitan area since 1996. However, these new towns generate lots of traffic and related problems in the areas including those new towns and Seoul as a result of increases in population and a lack of ecological-self-sufficiency. Currently, construction of another new town is under deliberation, and what should be a major consider is the notion that the new town be located within a wide, green zone. Many …studies have revealed that green space can play an important role in improving urban eco-meteorological capability and air quality. In order to analyze the urban heat island which will be created by the new urban development, and to investigate the local thermal environment and its negative effects caused by a change of land use type and urbanization, Landsat TM images were used for extraction of urban surface temperature according to changes of land use over the last 15 years. These data are analyzed together with digital land use and topographic information. As a study result, it was found the urban heat island of the study area from 1985 to 1999 rapidly developed which showed a difference of mean temperature above +2.0. Before the Bundang new town construction the temperature of the residential area was the same as a forest, but during the new town construction in 1991 analysis revealed the creation of an urban heat island. The temperature of a forest whose size is over 50% of the investigation area was lowest, and thus the presence of a forest is believed to have a direct cooling effect on the urban environment and its surroundings. The mean temperature of the residential and commercial areas in the study was found to be +4.5 higher than the forest, and therefore this part of land use is believed to be the main factor causing the temperature increase of the urban heat island. Show more

Keywords: urban heat island, new town development, urban climate, landsat TM hand 6, air corridor

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 641-645, 2005

Authors: LI, Chang-hai | SHI, Peng-fei

Article Type: Research Article

Abstract: Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of β-naphthalenesulfonic acid (NSA) and sulfuric acid (H_2 SO_4 ) from their solution at 25 °C onto weakly basic resin D301R. Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA. The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model. …The ideal adsorbed solution theory (IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria. The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA, respectively, yields the favorable representation of the bisolute competitive adsorption behavior. Show more

Keywords: β-naphthalenesulfonic acid, adsorption, weakly basic resin

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 646-649, 2005

Authors: WANG, Han-jie | LI, Jing | LU, Xiao-zhen | JIN, Yong-can

Article Type: Research Article

Abstract: A new technique was introduced for sand stabilization and re-vegetation by use of lignin sand stabilizing material (LSSM). LSSM is a reconstructed organic compound with lignin as the most dominant component from the extracts of black-liquor issued by straw pulp paper mills. Unlike the polyvinyl acetate or foamed asphalt commonly used for dune stabilization, the new material is plant-friendly and can be used with virescence actions simultaneously. The field experimental study was conducted since 2001 in …China's Northwest Ningxia Hui Autonomous Region and has been proved that LSSM is effective in stabilizing the fugitive dunes, making the arenaceous plants survive and the bare dune vegetative. The advisable solution concentration is 2% and the optimal field spraying quantity is 2.5 L/m^2 . The soil nutrients of the stabilized and greened dune, such as organic matter, available phosphorous and total nitrogen are all increased compared with the control treatment, which is certainly helpful to the growth of arenaceous plants. The technique is worthwhile to be popularized because it is provided not only a new method for desertification control but also an outlet for cleaning contaminants issued from the straw paper mills. Show more

Keywords: experimental study, lignin sand stabilizing material (LSSM), black-liquid, straw pulp paper mills

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 650-654, 2005

Authors: ZHANG, Li-li | ZHANG, Bo | HUANG, Yu-feng | CAI, Wei-min

Article Type: Research Article

Abstract: In some industrial plants, wastewater was intermittently or seasonally generated. There may be periods during which wastewater treatment facilities have to be set into an idle phase over several weeks. When wastewater was generated again, the activated sludge flocs may have disintegrated. In this experiment, re-activation characteristics of aerobic granular sludge starved for 2 months were investigated. Specific oxygen utilization rate (SOUR) was used as an indicator to evaluate the metabolic activity …of the sludge. The results revealed that aerobic granular sludge could be stored up to two months without running the risk of losing the integrity of the granules and metabolic potentials. The apparent color of aerobic granules stored at room temperature gradually turned from brownish-yellowish to gray brown. They appeared brownish-yellowish again 2 weeks after re-activation. The velocity and strength of granules after 2-month idle period could be fully restored about 3 weeks after re-activation. Metabolic activity, however, dropped to 15.8 mg O_2 /(g MLVSS·h) i.e. 74% reduction after 2 months of storage. After restarting the reactor, it took 2 weeks that SOUR of up to 48.5 mg O_2 /(g MLVSS·h) was achieved. A stable effluent COD concentration of less than 150 mg/L was achieved during the re-activation process. Show more

Keywords: aerobic granular sludge, re-activation characteristics, SBR, specific oxygen consumption rate

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 655-658, 2005

Authors: XIA, Wen-xiang | ZHENG, Xi-lai | LI, Jin-cheng | SONG, Zhi-wen | ZHOU, Li | SUN, Hao-fen

Article Type: Research Article

Abstract: Different kinds of mineral nutrients (NO_3 -N, NH_4 -N and PO_4 -P) were applied in the simulated oil-polluted seawater for enhancing oil biodegradation in the N/P ratio 10:1 and 20: 1. Although indigenous microorganisms have the ability to degrade oil, adding nutrients accelerated biodegradation rates significantly. For the group amended with NO_3 -N and PO_4 -P in the ratio 10:1, the reaction rate coefficient was 4 times …higher than the natural biodegradation. Chemical and microbiological analysis showed that the optimal N/P ratio in the system is 10:1, and microorganisms tend to utilize nitrate rather than ammonium as N source. Show more

Keywords: oil spill, biodegradation kinetics, N/P ratio, microbial population

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 659-661, 2005

Authors: WANG, Hong-qi | SHU, Yan | QI, Yong-qiang | ZHANG, Jun

Article Type: Research Article

Abstract: A series of simulation experiments of nitrogen transportation, absorption and transformation were conducted, and the different cropping patterns of winter wheat and wastewater irrigation plans were taken into consideration. Based on the experiments, an integrated model of crop growth, roots distribution, water and nitrogen absorption by roots, water and nitrogen movement and transformation in soilcrop system by two-dimension was developed. Parameters and boundary conditions were identified and an effective computing method for …optimizing watering and wastewater irrigating plans was provided. Show more

Keywords: nitrogen absorption and movement, integrated numerical model, soil-crop system

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 662-666, 2005

Authors: DING, Yu | MIAO, Jin-lai | LI, Guang-you | WANG, Quan-fu | KAN, Guang-feng | WANG, Guo-dong

Article Type: Research Article

Abstract: Glutathione (GSH) and GSH-related enzymes play a great role in protecting organisms from oxidative damage. The GSH level and GSH-related enzymes activities were investigated as well as the growth yield and malonyldialdehyde (MDA) content in the Antarctic ice microalga Chlamydomonas sp. ICE-L exposure to the different cadmium concentration in this paper. The results showed that the higher concentration Cd inhibited the growth of ICE-L significantly and Cd would induce formation of MDA. At the same time, …it is clear that GSH level, glutathione peroxidases (GPx) activity and glutathione S-transferases (GST), activity were higher in ICE-L exposed to Cd than the control. But GR activity dropped notably when ICE-L were cultured in the medium containing Cd. Increase of GSH level, GPx and GST activities acclimate to oxidative stress induced by Cd and protect Antarctic ice microalga Chlamydomonas sp. ICE-L from toxicity caused by Cd exposure. These parameters may be used to assess the biological impact of Cd in the Antarctic pole region environment. Show more

Keywords: antarctic ice microalgae, Chlamydomonas sp. ICE-L, glutathione, glutathione peroxidase, glutathione reductase, glutathione S-transferase, cadmium

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 667-671, 2005

Authors: ZHU, Guang-wei | CHI, Qiao-qiao | QIN, Bo-qiang | WANG, Wen-min

Article Type: Research Article

Abstract: Surface water was taken from river mouth to the central area of Meiliang Bay, Taihu Lake, a large shallow eutrophic lake in China. Suspended solids were condensed by centrifugation 25 L surface water samples from each selected site. Suspended solids and surface sediments were further freeze-dried and microwave digested before determining the metals by ICP-AES. Among the metals analyzed in suspended solids and sediments, contents of Cr, Cu, Mn, Ni, and Zn in suspended solids were …significantly higher than those in sediments while contents of Al, Ba, Be, Ca, Co, Fe, K, Mg, Pb, and V in suspended solids were 10%–30% higher than those in sediments. Sr and Ti contents in suspended solids and sediments were very similar. Na content in suspended solids was lower than that in sediments. Heavy metals were significantly accumulated in suspended solids. From the river mouth to the center of Meiliang Bay, contents of Cr, Cu, Pb, and Zn in suspended solids showed a gradual decreasing trend indicating the river (Zhihugang River) still discharged large quantity of heavy metalsto Meiliang Bay. The study suggests that the geochemical behaviors and ecological effects of heavy metals in suspended solids may serve as a good indicator for the pollution of lake. Show more

Keywords: shallow lakes, suspended solids, heavy metals, Taihu Lake

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 672-675, 2005

Authors: YANG, Zhi-feng | ZHANG, Wen-guo

Article Type: Research Article

Abstract: A case study is introduced and discussed concerning water dispute of misuse and pollution between up- and down-stream parts. The relations between water usage and local industrial structures are analyzed. Results show it is important to change industrial structures of the target region along with controlling water pollution by technical and engineering methods. Three manners of upstream-downstream cooperation are presented and discussed based on the actual conditions of Guangting Reservoir watershed, Two typical scenarios are …supposed and studied along with the local plan on water resources development. The best solution for this cooperation presents a good way to help the upstream developing in a new pattern of eco-economy. Show more

Keywords: watershed, cooperation, upstream-downstream, industrial structures, Guanting Reservoir

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 676-680, 2005

Authors: Kumar, A. Ganesh | Sekaran, G. | Swarnalatha, S. | Prasad, B. Rao

Article Type: Research Article

Abstract: The wastewater discharged from tanneries lack biodegradability due to the presence of recalcitrant compounds at significant concentration. The focal theme of the present investigation was to use chemo-autotrophic activated carbon oxidation (CAACO) reactor, an immobilized cell reactor using chemoautotrophs for the treatment of tannery wastewater. The treatment scheme comprised of anaerobic treatment, sand filtration, and CAACO reactor, which remove COD, BOD, TOC, VFA and sulphides respectively by 86%, 95%, 81%, 71% and …100%. Rice bran mesoporous activated carbon prepared indigenously and was used for immobilization of chemoautotrophs. The degradation of xenobiotic compounds by CAACO was confirmed through HPLC and FT-IR techniques. Show more

Keywords: chemo-autotrophic activated carbon oxidation (CAACO), mesoporous rice bran activated carbon, xenobiotic

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 681-685, 2005

Authors: LIU, Jian-dong | ZHOU, Xiu-ji | CHEN, De-liang | OUYANG, Zhi-yun | WANG, Xiao-ke | Christine, Achberger

Article Type: Research Article

Abstract: A biogeochemical model (DNDC) is combined with a plant ecological model to estimate N_2 O emission from rice paddy fields in the Yangtze River Delta region. The model is driven by local meteorological, soil, and physiological data and is validated for 1999 and 2000 at a site in the region, which showed that the simulated N_2 O emissions agree fairly well with the observed data. This adds some confidence in the estimated N_2 …O emissions during 1950 and 2000 in the Hangzhou Region. A significant correlation between the N_2 O emissions and the population for the Hangzhou Region is found, which is due to a combination of increased application of fertilizers and cultivated area. Such a correlation can not be established for the whole Yangtze River Delta region when the data of both urban and rural areas are included. However, when the data from the heavily urbanized areas are excluded, a significant correlation between population and N_2 O emissions emerges. The results show clearly that both the temporal and the spatial N_2 O emissions have significant positive relationship with population under traditional farming practice. These results have implications for suitable mitigation options towards a sustainable agriculture and environment in this region. Show more

Keywords: simulation, temporal and spatial N_2O emissions, Yangtze River Delta, China

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 686-690, 2005

Authors: SHAO, Jing-an | HUANG, Xue-xia | GAO, Ming | WEI, Chao-fu | XIE, De-ti | CAI, Zu-cong

Article Type: Research Article

Abstract: The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice (T1), no-tillage and ridge culture of rice (T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation (T4)) were measured with the closed chamber technique …in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH<FORMULA>_4 emission from paddy fields under these land management practices. In 1996 and 1998, CH_4 emission was 71.48% and 78.82% (T2), 65.93% and 57.18% (T3), and 61.53% and 34.22% (T4) of that in T1 during the rice growing season. During the non-rice growing season, CH_4 emission from rice fields was 76.23% in T2 and 38.69% in T1. The accumulated annual CH_4 emission in T2, T3 and T4 in 1996 decreased by 33.53%, 63.30% and 65.73%, respectively, as compared with that in T1. In 1998, the accumulated annual CH_4 emission in T1, T2, T3 and T4 was 116.96 g/m^2 , 68.44 g/m^2 , 19.70 g/m^2 and 11.80 g/m^2 , respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH_4 emission observed. The relative contribution of various influencing factors to CH_4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH_4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH_4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH_4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global (climatic) change. Show more

Keywords: land use pattern, microcosmic cultivation scale, fluxes of CH_4 emission, paddy field

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 691-698, 2005

Authors: CHI, Yong | WEN, Jun-ming | ZHANG, Dong-ping | YAN, Jian-hua | NI, Ming-jiang | CEN, Ke-fa

Article Type: Research Article

Abstract: The HCl emission characteristics of typical municipal solid waste (MSW) components and their mixtures have been investigated in a ϕ150 mm fluidized bed. Some influencing factors of HCl emission in MSW fluidized bed incinerator was found in this study. The Hclemission is increasing with the growth of bed temperature, while it is decreasing with the increment of oxygen concentration at furnace exit. When the weight percentage of auxiliary coal is increased, the conversion rate of Cl to …HCl is increasing. The HCl emission is decreased,if the sorbent (CaO) is added during the incineration process. Based on these experimental results, a 14 × 6 × 1 three-layer BP neural networks prediction model of HCl emission in MSW/coal co-fired fluidized bed incinerator was built. The numbers of input nodes and hidden nodes were fixed on by canonical correlation analysis technique and dynamic construction method respectively. The prediction results of this model gave good agreement with the experimental results, which indicates that the model has relatively high accuracy and good generalization ability. It was found that BP neural network is an effectual method used to predict the HCl emission of MSW/coal cofired fluidized bed incinerator. Show more

Keywords: municipal solid waste (MSW), HCl emission, fluidized bed, BP neural networks, prediction model

Citation: Journal of Environmental Sciences, vol. 17, no. 4, pp. 699-704, 2005