Journal of Environmental Sciences - Volume 16, issue 2

Authors: MU, Yu-jing | WU, Hai | WU, Peng-zhang | WANG, Yue-si

Article Type: Research Article

Abstract: Vertical distributions of COS and CS_2 were measured at a meteorological tower in Beijing City. The mixing ratios of COS and CS_2 are in the range of 371-1681 pptv and 246-1222 pptv, respectively. The significant high mixing ratios of the two compounds at ground level and distinct vertical distributions indicated the existence of strong anthropogenic sources of COS and CS_2 in Beijing City. Domestic stoves and central heaters are important …sources of COS during winter season. Cesspools may play significant role on COS over whole seasons. Chemical productions may be responsible for the observed high mixing ratios of CS_2 in Beijing City. Show more

Keywords: COS, CS_2, vertical distribution

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 226-229, 2004

Authors: Tateda, Masafumi | Fujita, Masanori | Ike, Michihiko | QUI, Yen-feng | Kokubo, Satoru

Article Type: Research Article

Abstract: Solid-liquid separation of the wastewater is very difficult because of high viscosity and high SS concentration. In this study, the effectiveness of preozonation on improving the settleability of the solids in wheat and sweet potato wastewaters was investigated using a bench-scale system and pilot treatment system respectively. Results showed that solid-liquid separation in the wheat wastewater was greatly improved by the decanter in the system (SS reduction from 24100 mg/L to 100 mg/L). However, preozonation practice …did not show a significant effect on solid-liquid separation of the sweet potato wastewater. Effect of preozonation on solid-liquid separation between wheat and sweet potato wastewater showed different. Show more

Keywords: Japanese spirit-distillery wastewater, wheat wastewater, sweet potato wastewater, London dumping convention, ozonation, settleability, solid-liquid separation

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 230-233, 2004

Authors: BIAN, Wen-juan | SHEN, Xue-you | LEI, Le-cheng

Article Type: Research Article

Abstract: The characteristic and mechanism of parachlorophenol (4-CP) degradation in an internal electrolysis system were investigated. The degradation rate of 4-CP was higher in acid solution than that of in neutral or alkaline solution. Addition of activated carbon could make 4-CP easier be degraded by the surface contact catalysis. The dissolved oxygen in solution could take part in the electrode reaction and intensify the degradation of 4-CP. By the analysis of intermediates of degradation of 4-CP, it …could be conferred that 4-CP was broken through the bond beside hydroxy firstly, then the bond beside chloride was broken and the chloride was dechlorinated simultaneously. Most intermediate products were glycerine, ethane diacid and acetic acid, while very few 1,4-butanedial and alcohols were found. Show more

Keywords: internal electrolysis, degradation, wastewater

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 234-237, 2004

Authors: FAN, Zhi-yun | HUANG, Jun-li | WANG, Peng | SU, Li-qiang | ZHENG, Yong-jie | LI, Ying-jie

Article Type: Research Article

Abstract: For the first time, kinetics of aniline oxidation with chlorine dioxide (ClO_2 ) were investigated systematically by detecting concentration of aniline with HPLC at regular intervals. Results showed that the reaction was first-order both in ClO_2 and in aniline, and the oxidation reaction could be described as second-order reaction. Stoichiometric factor η was experimentally determined to be 2.44. The second-order-reaction rate constant k was 0.11 L (mol ˙ s) under …condition of pH 6.86 and water temperature (T_w ) 287K. Reaction activation energy was 72.31 kJ/mol, indicating that the reaction could take place under usual water treatment conditions. The reaction rate constants in acidic and alkali media were greater than that in neutral medium. Chlorite ion could slightly in crease reaction rate in acidic medium. p-aminophenol and azobenzene were detected by GC-MS as intermediates. Show more

Keywords: chlorine dioxide, aniline, kinetics

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 238-241, 2004

Authors: HUANG, Ya-ji | JIN, Bao-sheng | ZHONG, Zhao-ping | XIAO, Rui | TANG, Zhi-yong | REN, Hui-feng

Article Type: Research Article

Abstract: The contents of eight trace elements (Mn, Cr, Pb, As, Se, Zn, Cd, Hg) in raw coal, bottom ash and fly ash were measured in a 220 t/h pulverized coal boiler. Factors affecting distribution of trace elements were investigated, including fly ash diameter, furnace temperature, oxygen content and trace elements' characters. One coefficient of Meij was also improved to more directly show element enrichment in combustion products. These elements may be classified into three groups according …to their distribution: Group 1: Hg, which is very volatile. Group 2: Pb, Zn, Cd, which are partially volatile. Group 3: Mn, which is hardly volatile. Se may be located between groups 1 and 2. Cr has properties of both group 1 and 3. In addition, the smaller diameter of fly ash, the more relative enrichment of trace elements (except Mn). The fly ash showed different adsorption mechanisms of trace elements and the volatilization of trace elements rises with furnace temperature. Relative enrichments of trace elements (except Mn and Cr) in fly ash are larger than that in bottom ash. Low oxygen content can not always improve the volatilization of trace elements. Pb is easier to form chloride than Cd during coal combustion. Trace elements should be classified in accordance with factors. Show more

Keywords: occurrence, volatility, relative enrichment, trace element, group of elements

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 242-246, 2004

Authors: YU, De-shuang | PENG, Yong-zhen | ZHANG, Kui

Article Type: Research Article

Abstract: The effect of seawater salinity on nitrite accumulation in short-range nitrification to nitrite as the end product was studied by using a SBR. Experimental results indicated that the growth of nitrobacteria was inhibited and veryhigh levels of nitrite accumulation at different salinities were achieved under the conditions of 25–28°C, pH 7.5–8.0, and the influent ammonia nitrogen of 40–70 mg/L when seawater flow used to flush toilet was less than 35% (salinity 12393 mg/L, Cl^- …6778 mg/L) of total domestic wastewater flow, which is mainly ascribed to much high chlorine concentration of seawater. Results showed that high seawater salinity is available for short-range nitrification to nitrite as the end product. When the seawater flow used to flush toilet accounting for above 70% of the total domestic wastewater flow, the removal efficiency of ammonia was still above 80% despite the removal of organics declined obviously (less than 60%). It was found that the effect of seawater salinity on the removal of organics was negative rather than positive one as shown for ammonia removal. Show more

Keywords: seawater salinity, short range nitrification-denitrification to nitrite as the end product, nitrite accumulation, organics removal efficiency, ammonia removal efficiency

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 247-251, 2004

Authors: XIE, Xiao-mei | LIAO, Min | HUANG, Chang-yong | LIU, Wei-ping | ABID, Subhani

Article Type: Research Article

Abstract: The impact of triazophos, bensulfuron-methyl, chlobenthiazone on soil biochemical characteristics in a paddy soil under controlled moisture (flooded soil) and temperature (25°C) condition was studied. The electron transport system (ETS)/dehydrogenase activity displayed a negative correlation with triazophos, bensulfuron-methyl, chlobenthiazone concentrations, and the activity decreased as the concentration of the pesticides increased. The higher doses, 5 and 10 field rates, of triazophos, bensulfuron-methyl, chlobenthiazone significantly inhibited ETS activity, while lower rates failed to …produce any significant reducing effect against the control. The relative toxicity of triazophos, bensulfuron-methyl, chlobenthiazone in decreasing the ETS activity was in the order: triazophos > chlobenthiazone > bensulfuron-methyl, irrespective of the rates of application. Triazophos, bensulfuron-methyl, chlobenthiazone caused an improvement in the soil phenol content and it increased with increasing concentration of triazophos, bensulfuron-methyl, chlobenthiazone. Triazophos, bensulfuron-methyl, chlobenthiazone incorporation did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to ETS activity. The phospholipid content was decreased with the addition of triazophos, bensulfuron-methyl, chlobenthiazone in the order of triazophos > chlobenthiazone > bensulfuron-methyl; and the toxicity of applied amount was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control. Show more

Keywords: triazophos, chlobenthiazone, bensulfuron-methyl, soil biochemical characteristic

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 252-255, 2004

Authors: YANG, Jing-cheng | HUANG, Jian-hui | PAN, Qing-min | TANG, Jian-wei | HAN, Xing-guo

Article Type: Research Article

Abstract: Land-use changes, especially the conversion of native forest vegetation to cropland and plantations in tropical region, can alter soil C and N pools and N availability for plant uptake. Deforestation, followed by shifting cultivation and establishment of rubber tree plantation, is a common land-use change in Xishuangbanna, southwest China. However the influence of this kind of land-use change on soil C and N dynamics in this region remains poorly understood. This study was conducted to assess …the effects of land-use change on soil C and N pools. Soil samples were collected on five adjacent plots, which belong to three land-use types including secondary forest-an acuminate banana (Musa itinerans) secondary forest and a male bamboo (Dendrocalamus membranaceae) secondary forest, shifting cultivation, and rubber tree (Hevea brasiliensis (H. B. K.) Muell. Arg.) plantation (one plot is 3-year-old, and another is 7-year-old). We measured soil bulk density (BP), pH value, moisture content and concentrations of soil organic carbon (SOC), total soil nitrogen (TSN), and inorganic N(NO^-_3 -N and NH_4^+ -N) at 0–3, 3–20, 20–40 and 40–60 cm depths, and calculated C and N pools in 0–20, 20–40, 40–60, and 0–60 cm soil layers. Compared with the adjacent secondary forests, shifting cultivation and establishment of rubber tree plantations resulted in significant decline in concentrations and stocks of SOC and TSN in 0–20 and 0–60 cm soil layers, and increase in pH and bulk density at 0–3, 3–20, and 20–40 cm depths. Soil moisture content decreased only in 0–20 cm surface soils in shifting cultivation and plantations. The dynamics of mineral N was much more complex, which had different trends among depths and ecosystems. Compared with the secondary forests, SOC stocks in 0–20 cm surface soils in shifting cultivation and rubber tree plantations (3-year-old plantation and 7-year-old plantation) decreased by 34.0%, 33%, and 23%; and TSN stocks decreased by 32.2%, 20.4%, and 20.4%, respectively, whereas the decreases of SOC and TSN stocks in 0–60 cm soil layers were much less. The results indicated that C and N losses were mainly occurred in 0–20 cm surface soil, followed by 20–40 cm layer. Show more

Keywords: soil organic carbon (SOC), total soil nitrogen (TSN), inorganic nitrogen, land-use change, tropical soil, Xishuangbana

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 256-261, 2004

Authors: YE, Qing-fu | WU, Jian-min | SUN, Jin-he

Article Type: Research Article

Abstract: The bioavailability of bound residue (BR) derived from ^{14} C-labeled chlorsulfuron in soil and effect of the main components of the BR on growth of rape (brassica napus) and rice (Oryza sativa L.) were investigated. The results showed that the BR with the concentration of 0.28 and 0.56 nmol/g air-dried soil, which was calculated by special radioactivity of ^{14} C-labeled chlorsulfuron parent compound, resulted in significant depression effect on growth of rape seedling. …It was assured that the main components (2-amino-4-methoxyl-6-methyl-1,3,5-triazine, 2-amino-4-hydroxyl-6-methyl-1,3,5-triazine, and 2-chloro-benzenesul-fonamide) of the BR did not inhibit the growth of rape and rice. LC-MS analysis demonstrated that the parent compound previously bound to the soil matrix could be again released and transformed into methanol-extractable residue during the course of rape growth. It was concluded that the molecular leading to the phytotoxicity to rape and rice in the BR is still the parent compound. Show more

Keywords: chlorsulfuron, bound residue, bioavailability, phytotoxicity, mechanism

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 262-267, 2004

Authors: WANG, Li-gang | JIANG, Xin | WANG, Fang | BIAN, Yong-rong | Forster, Stephan | Martens, Dieter

Article Type: Research Article

Abstract: A silicagel fractionation procedure for environmental sample extracts, which separates chlorinated hydrocarbons (CHCs) and organophosphorus, pyrethroid pesticides into two groups for subsequent instrumental analysis, was developed in this study. This method was achieved by optimizing the fraction cut-off volume of elution and different solvents. Using fully activated silica gel and cut-off CHCs collection after 10 mi 10% dichloromethane (DCM) in n-hexane passing through the column resulted in satisfactory separation of CHCs and …organophosphorus, pyrethroid pesticides. This procedure had a higher reliability for CHCs than for organophosphorus, pyrethroid pesticides, because there is a relatively reliable recovery for CHCs. This approach is less expensive due to reducing sample pre-treatment time and solvent consumption. Show more

Keywords: CHCs, organophosphorus pesticides, pyrethroid pesticides, silicagel fractionation

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 268-271, 2004

Authors: YU, Zheng-zhe | SUN, De-zhi | LI, Chang-hai | SHI, Peng-fei | DUAN, Xiao-dong | SUN, Guo-rong | LIU, Jun-xin

Article Type: Research Article

Abstract: The performance of UV/H_2 O_2 , UV/O_3 and UV/H_2 O_2 /O_3 oxidation systems for treating spent caustic from an ethylene plant was investigated. In UV/H_2 O_2 system, with the increase of H_2 O_2 dosage, removal efficiencies of COD and the ratio of biochemical oxygen demand (BOD) to chemical oxygen demand (COD) of the effluent were increased and a …better performance was obtained than the H_2 O_2 system alone. In UV/H_2 O_2 system, removal efficiency of COD reach 68% under the optimum condition, and BOD/COD ratio was significantly increased from 0.22 to 0.52. In UV/O_3 system, with the increase of O_3 dosage, removal efficiency of COD and BOD/COD ratio were increased, and a better performance was obtained than the O_3 system alone. Under the optimum condition, removal efficiency of COD was 54%, and BOD/COD ratio was significantly increased from 0.22 to 0.48. In UV/H_2 O_2 /O_3 system, COD removal efficiency was found to be 22.0% higher than UV/O_3 system. Show more

Keywords: spent caustic, photochemical oxidation, UV/O_3 system, UV/H_2O_2 system, UV/H_2O_2/O_3 system

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 272-275, 2004

Authors: XU, Han-qiu | CHEN, Ben-qing

Article Type: Research Article

Abstract: World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. This resulted in a phenomenon known as an urban heat island (UHI). A study on the UHI in Xiamen of China was carried out using remote sensing technology. Satellite thermal infrared images were used to determine surface radiant temperatures. Thermal remote sensing data were obtained from band …6 of two Landsat TM/ETM^+ images of 1989 and 2000 to observe the UHI changes over 1 1-year period. The thermal infrared bands were processed through several image enhancement technologies. This generated two 3-dimension-perspective images of Xiamen's urban heat island in 1989 and 2000, respectively, and revealed heat characteristics and spatial distribution features of the UHI. To find out the change of the UHI between 1989 and 2000, the two thermal images were first normalized and scaled to seven grades to reduce seasonal difference and then overlaid to produce a difference image by subtracting corresponding pixels. The difference image showed an evident development of the urban heat island in the 11 years. This change was due largely to the urban expansion with a consequent alteration in the ratio of sensible heat flux to latent heat flux. To quantitatively compare UHI, an index called Urban-Heat-Island Ratio Index (URI) was created. It can reveal the intensity of the UHI within the urban area. The calculation of the index was based on the ratio of UHI area to urban area. The greater the index, the more intense the UHI was. The calculation of the index for the Xiamen City indicated that the ratio of UHI area to urban area in 2000 was less than that in 1989. High temperatures in several areas in 1989 were reduced or just disappeared, such as those in old downtown area and Gulangyu Island. For the potential mitigation of the UHI in Xiamen, a long-term heat island reduction strategy of planting shade trees and using light-colored, highly reflective roof and paving materials should be included in the plans of the city planers, environmental managers and other decision-makers to improve the overall urban environment in the future. Show more

Keywords: remote sensing, urban heat island, urban-heat-island ratio index, digital brightness model, Xiamen City

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 276-281, 2004

Authors: LI, Ying | CHEN, Yah-ming | ZHAO, Kong-shuang | Takumi, HIKIDA

Article Type: Research Article

Abstract: The phenomenon of two dilute aqueous phases composed of sodium dodecylsulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) was investigated under various conditions such as concentrations and molar ratios of the two surfactants, the addition of sodium chloride and temperature. Vesicles formation was found in the both phases by TEM image.

Keywords: aqueous surfactant two-phase (ASTP), cationic-anionic surfactants, vesicles vesicles vesicles

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 282-284, 2004

Authors: Thakare, Sanjay R.

Article Type: Research Article

Abstract: To develop more efficient chemical methods for the demineralization of organic pollutants from water bodies, which one was also mimic to the nature, a degradation of methylene blue by Fe (III) and H_2 O_2 in the absence of light instead of Fe (II) and H_2 O_2 was studied. Results showed that use of Fe (III) is more promising than Fe (II). The present study reflects that Fenton reaction is more …efficient, in the presence of a small amount of salicylic acid is added which is a one of the priority pollutant. Show more

Keywords: advanced oxidation technology, Fenton reaction, iron (III), catalytic degradation, environmental application

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 285-287, 2004

Authors: SHI, Xiao-li | YANG, Liu-yan | WANG, Feng-ping | XIAO, Lin | JIANG, Li-juan | KONG, Zhi-ming | GAO, Guang | QIN, Bo-qiang

Article Type: Research Article

Abstract: Growth and uptake of exogenous phosphate by Microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. Relatively high temperature, long photoperiod and strong turbulence increased the cell density of M. aeruginosa in these batch cultures. The initial rapid uptake of phosphate by M. aeruginosa was independent of the temperature, photoperiod, and turbulence. Similarly, maximum exogenous phosphate uptake was not related to …these environmental factors. However, elevated temperature and turbulence shortened the time, required to obtain maximum P accumulation. The growth of M. aeruginosa could alleviate the phosphorous leakage. Total amounts of exogenous phosphate uptake to M. aeruginosa and the phosphorus leakage of M. aeruginosa were significantly influenced by the growth state of M. aeruginosa closely correlated with the environmental factors. The maximum volume of exogenous phosphate uptake to M. aeruginosa was 46% of added exogenous phosphate in water with 16 hours of photoperiod. Thus, total amounts of exogenous phosphate uptake to M. aeruginosa were more strongly affected by the photoperiod length than temperature and turbulence. Show more

Keywords: Microcystis aeruginosa, exogenous phosphate, photoperiod, temperature, turbulence, uptake

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 288-292, 2004

Authors: WU, Xiu-guang | SHEN, Yong-ming | ZHENG, Yong-hong | YANG, Zhi-feng

Article Type: Research Article

Abstract: The planar 2D k-ϵ double equations' turbulence model was adopted and transformed into non-orthogonal curvilinear coordinates. The concentration convection-diffusion was introduced to planar 2D SIMPLEC algorithm of flow in non-orthogonal curvilinear coordinates. The numerical model of pollutant transportation in non-orthogonal curvilinear coordinates was constructed. The model was applied to simulate the flow and pollutant concentration fields. In the testing concentration field, two optimal operations of contamination discharging both along bank and in …the centerline at the first bend of the meandering channel were adopted. Comparison with available data showed the model developed was successful, was valuable to engineering application. Show more

Keywords: curvilinear coordinates, diffusion-transportation, SIMPLEC algorithm, concentration fields, meandering channel

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 293-296, 2004

Authors: GUO, Jin-long | MENG, Jun | LI, GUI-ping | LUAN, Zhao-kun | TANG, Hong-xiao

Article Type: Research Article

Abstract: The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. The physicochemical interaction forces between the filter media and suspended particles and their influence on deep bed filtration process were also studied theoretically. Through the comparison of the hydraulic and physicochemical forces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the micro-flocculation deep bed filtration was carried out in the No. 9 …Potable Water Treatment Plant of Beijing, and the experimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoretical prediction was reasonably consistent with the experimental results under different conditions, which indicated that the regulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of the physicochemical interactions. Further theoretical and experimental research should be carried out to investigate the interaction mechanism and its application in the deep bed filtration and other cases. Show more

Keywords: capillary, micro-flocculation, filtration, physicochemical, interaction

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 297-301, 2004

Authors: LU, Jiang | ONITSUKA, Katsutada

Article Type: Research Article

Abstract: Foamed waste glass (FWG) material is newly developed for the purpose to utilize the waste glassware and other waste glass. FWG has a multi-porous structure that consists of continuous or discontinuous voids. Hence lightweight but considerable stiffness can be achieved. In the present study, the manufacture and engineering properties of FWG are introduced first. Then, the utilizations of FWG are investigated in laboratory tests and field tests. Some case studies on design and construction work are …also reported here. Through these studies we know that the discontinuous void material can be utilized as a lightweight fill material, ground improvement material and lightweight aggregate for concrete. On the other hand, the continuous void material can be used as water holding material for the greening of ground slope and rooftop, and as clarification material for water. Show more

Keywords: foamed waste glass (FWG), engineering properties, lightweight material, construction

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 302-307, 2004

Authors: DUAN, Guang-ming | ZHAO, Jing-zhu | LIU, Guo-hua | KE, Bing | XIAO, Han | WU, Gang | DENG, Hong-bing

Article Type: Research Article

Abstract: This paper assess the eco-environmental benefits that may come from the middle route project of China's South-North Water Transfer Scheme (SNWT) with principles and methods of eco-economics and planning reports of SNWT's middle route project. Some benefits were calculated in monetary units. To make sure that the results can be comparable with normal monetary indices, concrete assessment objects and the parameters are prudently selected according to the major characteristics of the project and its water import …region. Primary assessment revealed that in different project construction stages, the benefit could be more than 13.07 billion RMB Yuan in 2010 and 19.79 billion RMB Yuan in 2030, respectively. The monetary value tends to increase with social-economic development. To realize these potential benefits, however, calls for more endeavors. Show more

Keywords: China's South-North Water Transfer Scheme (SNWT), the middle route project of South-North Water Transfer (MRPSNWT), assessment, ecosystem services, monetary indices

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 308-315, 2004

Authors: HAO, Zheng-ping | HU, Chun | JIANG, Zheng | LU, G. Q.

Article Type: Research Article

Abstract: ZrO_2 -Al_2 O_3 composite oxides and supported Ni catalysts were prepared, and characterized by N_2 adsorption/desorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The catalytic performance and carbon deposition was also investigated. This mesoporous composite oxide is shown to be a promising catalyst support. An increase in the catalytic activity and stability of methane and carbon dioxide reforming reaction was resulted from the zirconia …addition, especially at 5wt% ZrO_2 content. The Ni catalyst supported ZrO_2 -Al_2 O_3 has a strong resistance to sintering and the carbon deposition in a relatively long-term reaction. Show more

Keywords: oxides, catalytic properties, methane reforming, carbon deposition

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 316-320, 2004

Authors: FANG, Zhan-qiang

Article Type: Research Article

Abstract: The level and pattern of residues of organochlorine pesticide and polychlorinated biphenyls (PCBs) were analyzed in sediment and mussel (Perna viridis) samples from ten coastal sites along the Pearl River Delta, South China. The range of total HCH was < 0.01 to 0.29 ng/g freeze-dried weight in sediment, and < 0.01 to 1.35 ng/g lipid weight in mussels. Average total DDTs concentrations ranged from < 0.01 to 1.04 ng/g in sediment, and < 0.01 to 148.5 …ng/g in mussels. Average total PCB concentrations ranged from 16.4 to 198.6 ng/g in sediment, and from 41 to 729.2 ng/g in mussels. Organochlorine pesticide and PCBs in mussels and sediments presented similar distribution patterns. The regression analysis indicated that PCBs concentrations in mussels were significantly correlated (p < 0.01) with concentrations in sediments. However, their concentrations in mussels were several times higher than the concentration detected in surrounding sediments. The major fraction of DDT related compounds measured in mussels and sediments was DDD. Based on average PCB concentrations, penta-, hexa-, and tetrachlorobiphenyls were preferentially accumulated by mussels as compared to the average sediment composition. According to the present results, three organochlorine polluted "hot spot" sites, including Victoria Harbour, Lingding Yang and Huangmao Sea, were found in the Pearl River estuarine zone. HCHs, DDTs and PCBs in all mussel samples were below the limits of 2, 0.2 and 5.0 μg/g wet weight recommended by the Technical Group of Guangdong Coastal Zone Resource Comprehensive Survey and U. S. Food and Drug Administration. Show more

Keywords: organochlorine pesticide, polychlorinated biphenyls, sediments, mussels, coastal waters

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 321-327, 2004

Authors: LI, Wei | WANG, Yi-zhong

Article Type: Research Article

Abstract: The relationship between adsorption behavior and photocatalytic mechanism of the two dyes was investigated. Adsorption isotherms showed that the adsorption of cationic pink FG was Langmuir type behavior, while the reactive brilliant red k-2G was Freundlich type behavior. The increasing pH favored the adsorption of FG but have little effect on the photodegradation. The increasing pH favored the adsorption and the photodegradation of K-2G. The presence of scavenger of h^+_{vd} and …OH^+ radical potassium iodide inhibited the degradation of k-2G, free radicals scavenger tetranitromethane inhibited the photodegradation of FG. These results indicated that the photodegradation of FG mainly via free radicals in solution, and the photodegradation of k-2G was mainly on the catalysts surface or near the interface of solid and solution by react with h^+_{vb} and surface-bound OH^+ . The different effect of SO^{2-}_4 , HCO^-_3 on the adsorption and photodegradation of two dyes confirmed these results. Show more

Keywords: photodegradation mechanism, adsorption behavior, dye

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 328-331, 2004

Authors: WANG, Wei-wu | ZHU, Li-zhong | WANG, Ren-chao

Article Type: Research Article

Abstract: Urban human thermal comfort (UHTC) is affected for interacting of weather condition and underlying surface framework of urban area. Urban underlying surface temperature value and Normalized Difference Vegetation Index (NDVI) were calculated using image interpreting and supervised classification technique by ERDAS IMAGE software using 1991 and 1999 Landsat TM images data. Reference to the relational standard of assessing human thermal comfort and other meteorology data of Hangzhou City in summer, air temperature …and relative humidity variation of different land types of underlying surface were inversed. By choosing discomfort index as an indictor, the spatial distribution characteristic and the spatial variation degree of UHTC were estimated and mapped on a middle scale, that is, in six districts of Hangzhou. The main characteristics of UHTC spatial variation from 1991 to 1999 were revealed using a GIS-based calculation model. The variation mechanism were analyzed and discussed from the viewpoint of city planning, construction and environmental protection. Show more

Keywords: urban human thermal comfort (UHTC), remote sensing (RS), geographic information system (GIS), spatial distribution, variation mechanism

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 332-338, 2004

Authors: ZHENG, Ping | LIN, Feng-mei | HU, Bao-lan | CHEN, Jian-song

Article Type: Research Article

Abstract: The anaerobic ammonia oxidation (Anammox) granular sludge bed reactor was started up successfully with nitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anammox granular sludge with good settling property and high conversion activity. The Anammox reactor worked well with the shortest HRT of 2.43 h. Under the condition that HRT was 6.39 h and influent concentration of ammonia and nitrite was 10 mmol/L, the removal of ammonia and nitrite was …97.17% and 100.00%, respectively. Corresponding volumetric total nitrogen loading rate and volumetric total nitrogen conversion rate were 100.83 mmol/(L ˙ d) and 98.95 mmol/(L ˙ d). The performance of Anammox reactor was efficient and stable. Show more

Keywords: nitrifying granular sludge, anaerobic ammonia oxidation (Anammox), granular sludge bed reactor, performance

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 339-342, 2004

Authors: YE, Yang-fang | MIN, Hang | DU, Yu-feng

Article Type: Research Article

Abstract: A bacterium (designated strain Y1) degrading acetanilide herbicide mefenacet was isolated from aerobic sludge. Based on the analyses of partial 16S rRNA gene, cellular fatty acid and BIOLOG-GN, and general physiological and biochemical characteristics, strain Y1 was identified as Sphingobacterium multivolum. Strain Y1 was able to degrade mefenacet used as sources of carbon and energy. Degradation of mefenacet was accompanied by producing the metabolites N-methylaniline and an unidentified compound with molecular weight …205, indicating a metabolic pathway of mefenacet initiated by hydrolysis of amido bond. Show more

Keywords: herbicide, mefenacet, Sphingobacterium, biodegradation

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 343-347, 2004

Authors: LI, Mei | QU, Jiu-hui | PENG, Yong-zhen

Article Type: Research Article

Abstract: The inactivation of microorganisms by pulsed magnetic field was studied. It was improved that the application of electromagnetic pulses evidently causes a lethal effect on E. coli cells suspended in phosphate buffer solution Na_2 HPO_4 /NaH_2 PO_4 (0.334/0.867 mmol/L). Experimental results indicated that the survivability (N/N_0 ; where N_0 and N are the number of cells survived per milliliter before and after electromagnetic pulses …application, respectively) of E. coli decreased with magnetic field intensity B and treatment time t. It was also found that the medium temperatures, the frequencies of pulse f, and the initial bacterial cell concentrations have determinate influences in destruction of E. coli cells by the application of magnetic pulses. The application of an magnetic intensity B = 160 mT at pulses frequency f = 62 kHz and treatment time t = 16 h result in a considerable destruction levels of E. coli cells (N/N_0 = 10^{-4} ). Possible mechanisms involved in sterilization of the magnetic field treatment were discussed. In order to shorten the treatment time, many groups of parallel inductive coil were used. The practicability test showed that the treatment time was shortened to 4 h with the application of three groups of parallel coil when the survivability of E. coli cells was less than 0.01%; and the power consumption was about 0.2 kWh/m^3 . Show more

Keywords: Escherichia coli bacteria, pulsed magnetic field, induced current, cell membrane

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 348-352, 2004