Journal of Environmental Sciences - Volume 16, issue 3

Authors: LU, Jiang | MODMOLTIN, Chirdchanin | ONITSUKA, Katsutada

Article Type: Research Article

Abstract: Utilization of industrial waste and surplus construction soft clay as construction material was recommended, and many attempts at geotechnical waste utilization were undertaken. This study aimed at the application of cement and a kind of industrial wastes, i.e. granulated blast furnace slag, on stabilization of surplus soft clay. The results showed that the cement and slag can successfully stabilize Ariake clays even though this high organic clay fails to be stabilized by lime and cement. Addition …of slag in cement for stabilization induces higher strength than cement alone for longer curing time. The application of the cement with slag is more suitable than cement alone for stabilization because of economical consideration. Show more

Keywords: surplus soft clay, stabilization, GBF slag, cement, organic matter, lime, humic acid

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 397-403, 2004

Authors: CAO, Zhi-Ping | Dawson, Richard

Article Type: Research Article

Abstract: Agroecosystem functional assessment indicators provide a necessary bridge between decision-makers and scientists. The development of acceptable indicators, however, remains a difficult task because the current knowledge and understanding of ecosystems is not sufficient to allow an objective assessment of all ecosystem functions. These difficulties were summarized from three perspectives. First, there are difficulties in individual function assessment. Of the four functions associated with agroecosystems-energy flow, materials cycling, information flow and value flow …– data on material cycling and information flow remain difficult to obtain and the indicators relatively immature. Secondly, there are difficulties of integration. During the assessment process, the integration of the agroecosystem functions remains the biggest obstacle. Until now, there has been no practical or effective methodology established to resolve the problem. At present, the makeshift approach has been to weight the various indicators and then add them together. Thirdly, there is the problem of obscure concepts and concept confusion. When assessments of agroecosystems are conducted, concepts such as structure, function, benefit, and resource utilization are used extensively. To date, no logical relationship (either real or implied) has been developed between any of these concepts. Are they causes and results such that the relationship between them is linear, or are they independent from one another such that the relationship is parallel? Thus far, the essence of this question is yet to be explored. Show more

Keywords: functional assessment, indicators, agroecosystems, ecological benefit

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 404-407, 2004

Authors: ZHOU, Yan-mei | LIU, Rui-xia | TANG, Hong-xiao

Article Type: Research Article

Abstract: The sorption behavior was determined for a model polycyclic aromatic hydrocarbon (PAH), i.e., phenanthrene (PHN), from water to three humic acids (HAs) and three sediments in different reacting time. The chemical compositions of HA samples were measured using cross polarization magic angle spinning carbon-13 (CPMAS^{13} C) NMR along with elemental analysis. The dissolved humic substances dissociating from solid HAs and sediments were characterized by ^1 H NMR. The experiments indicated that the …sorption modes and mechanisms of natural sorbents for PHN varied significantly between short (<7 d) and long contact time and the reaction time should be taken into consideration in studying the overall sorption process. The sorption capacity (K'_1 ) and exponent (n) might be relative to the properties of dissolved humic materials in initial stage but the solid aromatic organic matter after long time reaction. According to the experiments performed in this investigation and the previous researches, a conceptive sorption model was established. Show more

Keywords: sorption, phenanthrene, humic acid, sediment, CPMAS ^{13}C NMR

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 408-413, 2004

Authors: HUANG, Yi | TAO, Shu

Article Type: Research Article

Abstract: Growth and photosynthesis responses were measured for Scots pine (Pinus sylvestris L. cv.) inoculated with ectomycorrhizal fungi (Suillus bovinus) under 6.5 and 25 mg/L Cu treatments to evaluate ectomycorrhizal seedlings' tolerance to heavy metal stress. Results showed that excessive Cu can significantly impair the growth and photosynthesis of pine seedlings, but such impairment is much smaller to the ectomycorrhizal seedlings. Under 25 mg/L Cu treatment, the dry weight of ectomycorrhizal seedlings is 25% lower than the …control in contrary to 53% of the non-mycorrhizal seedlings, and the fresh weight of ectomycorrhizal roots was significantly higher than those of non-mycorrhizal roots, about 25% and 42% higher at 6.5 and 25 mg/L Cu treatments respectively. Furthermore, ectomycorrhizal fungi induced remarkable difference in the growth rate and pigment content of seedlings under excessive Cu stress. At 25 mg/L Cu, the contents of total chlorophyll, chlorophyll-a and chlorophyll-b were 30% higher in ectomycorrhizal plants than those in non-mycorrhizal plants. O_2 evolution and electron transport of PSI and PSII were restrained by elevated Cu stress. However, no significant improvement was observed in reducing the physiological restraining in ectomycorrhizal seedlings over the non-mycorrhizal ones. Show more

Keywords: copper, ectomycorrhizal Pinus sylvestris, photosynthesis, growth

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 414-419, 2004

Authors: XU, Yi | WANG, Dong-Sheng | TANG, Hong-Xiao

Article Type: Research Article

Abstract: This article discusses the influential factors on Al_{13} separation considering the interaction of sulfate with various polyaluminum chloride (PACl). The experimental results showed that the basicity (B=[OH]/[Al]), the concentration of PACl and Al/SO_4 ratio exhibited significant roles in the PACl-sulfate reaction. It indicated that different species in various PACl underwent different reaction pathway with sulfate. The Al_c , colloidal species, formed precipitation quickly with sulfate, while …Al_b , oligomers and polymers, undergoes slow crystallization. And Al_a , monomers, reacts with sulfate to form soluble complexes. The kinetic difference of reaction made it possible to realize the separation of Al_b and further purification. The decrease of Al_a resulted in the limit of ferron method was also mentioned. Show more

Keywords: PACl, sulfate, Al_{13}, kinetic, separation

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 420-422, 2004

Authors: HUANG, Hong | WANG, Xiao-dong | DAI, Xuan-li | YU, Ya-juan | WANG, Lian-sheng

Article Type: Research Article

Abstract: Holographic quantitative structure-activity relationship (HQSAR) is an emerging QSAR technique with the combined application of molecular hologram, which encoded the frequency of occurrence of various molecular fragment types, and the subsequent partial least squares (PLS) regression analysis. In this paper, the acute toxicity data to the guppy (poecilia reticulata) for a series of 56 substituted benzenes, phenols, aromatic amines and nitro-aromatics were subjected and this resulted in a model with a high predictive ability. The …influence of fragment size and fragment distinction parameters on the quality of HQSAR model was investigated. The robustness and predictive ability of the model were also validated by leave-one-out (LOO) cross-validation procedure and external testing data set. Show more

Keywords: benzene derivatives, HQSAR, molecular hologram, acute toxicity, guppy (poecilia reticulata)

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 423-427, 2004

Authors: MA, Bi-yao | LI, Wei | JING, Guo-hua | SHI, Yao

Article Type: Research Article

Abstract: In the system of nitric oxide removal from the flue gas by metal chelate absorption, it is an obstacle that ferrous absorbents are easily oxidized by oxygen in the flue gas to ferric counterparts, which are not capable of binding NO. By adding iron metal or electrochemical method, Fe^{III} (EDTA) can be reduced to Fe^{II} (EDTA). However, there are various drawbacks associated with these techniques. The dissimilatory reduction of Fe^{III} …(EDTA) with microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Ammonium salt instead of nitrate was used as the nitrogen source, as nitrates inhibited the reduction of Fe^{III} due to the competition between the two electron acceptors. Supplemental glucose and lactate stimulated the formation of Fe^{II} more than ethanol as the carbon sources. The microorganisms cultured at 50°C were not very sensitive to the other experimental temperature, the reduction percentage of Fe^{III} varied little with the temperature range of 30–50°C. Concentrated Na_2 CO_3 solution was added to adjust the solution pH to an optimal pH range of 6–7. The overall results revealed that the dissimilatory ferric reducing microorganisms present in the mix-culture are probably neutrophilic, moderately thermophilic Fe^{III} reducers. Show more

Keywords: dissimilatory ferric reducing microorganisms, Fe^{III} (EDTA), microbial reduction, mix-culture

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 428-430, 2004

Authors: SHEN, Zhuang-zhi | CHENG, Jian-zheng | WU, Sheng-ju

Article Type: Research Article

Abstract: Degradation effect of organic pollutant on pentachlorophenol (PCP) is researched by ultrasound. PCP is treated by low frequency (16 kHz) and high frequency (800 ± 1 kHz), and bi-frequency. The results of investigation on the ultrasonic destruction of PCP showed that the rate of PCP degradation at the same conditions is the highest at bi-frequency, and the lowest at 16 kHz. In the presence of Fenton type reagent the degradation rate of PCP is highest at …bi-frequency (20.93 times) as compared to the stirring system. This ratio is 4.91 and 1.06 at 800 kHz and 16 kHz, respectively. The studies showed the bi-frequency is an effective method for pollutants degradation, but it is need make further study. Taking 800 kHz for example, under the same conditions, the smaller pH of the solution, the higher is the reaction rate. A similar situation applied to TOC, but the TOC removal lags behind degradation of PCP. This indicated the PCP is not completely mineralized. The ultrasound is somewhat enhanced for degradation of PCP and mineralization with only addition of CuSO_4 , but the combination of ultrasound and Fenton type reagent is effective method for PCP degradation and mineralization. The rate of PCP degradation and TOC removal appeared to follow pseudo-first-order reaction kinetic law. Show more

Keywords: sonochemistry, Fenton type reagent, bi-frequency, pentachlorophenol hydroxyl radical

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 431-435, 2004

Authors: ZHAO, Wen-wu | FU, Bo-jie | CHEN, Li-ding | ZHANG, Qiu-ju | ZHANG, Yin-hui

Article Type: Research Article

Abstract: The purpose of this article is to identify the effect of land-use pattern on rainfall-runoff and runoff-sediment relations in Zichang watershed of the Loess Plateau. From 1986 to 1997, many farmlands changed into grassland or woodland, especially the farmland in steep slope positions or far away from the river. The change of land-use pattern altered the rainfall-runoff and runoff-sediment relationships, and led to higher slope of trend curves (STCs) of annual rainfall-runoff mass curve and runoff-sediment …mass curve in 1990s than that in 1980s. It is implied that more soil and water loss yielded in 1990s. In order to reduce soil loss, more attentions should be paid to land-use pattern and some grass or other herbaceous filter strips should be built along rivers. Show more

Keywords: land-use, rainfall, runoff, sediment concentration, double mass curve, slope of trend curve, Loess Plateau

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 436-442, 2004

Authors: ZHANG, Kai-song | ZHOU, Qi-xing | XIAO, Hong

Article Type: Research Article

Abstract: Combined flocculants with low ecological risk are urgently required in water supply and wastewater treatment in China. A novel flocculant was thus developed under the condition of low ecological risk (noted as CAS). The experiments to examine wastewater treatment performance of the new product showed that there was favourable performance in the flocculation process in contrast to commercial flocculants in treating kaolin suspensions, municipal effluent and domestic wastewater. Flocculation performance included the …turbidity removal rate, sediment character and a decrease in COD (chemical oxygen demand). The sediment time of flocculation is short and the removal rate of turbidity treated by CAS is high compared with PAC (polyaluminum-chloride), PAM (polyacrylamide) and the combined addition of PAC and PAM. The optimal concentration required to affect flocculation processes is dependent on kaolin concentration and the character of the wastewater within the range examined. It also showed that CAS is effective to treat wastewater with high turbidity. Show more

Keywords: combined flocculation, turbidity, sediment velocity, COD, ecological risk

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 443-446, 2004

Authors: Verma, R.J. | Vasu, Archana | Saiyed, Abdul Alim

Article Type: Research Article

Abstract: Oral administration of arsenic trioxide (3 and 6 mg/kg body weight/d) for 30 d caused, as compared with vehicle control, dose-dependent significant reductions in body weight, absolute weight, protein, glycogen, as well as, total, dehydro and reduced ascorbic acid contents both in the liver and kidney of arsenic-treated mice. Succinic dehydrogenase (SDH) and phosphorylase only in the liver activities were significantly reduced in a dose-dependent manner. Acid phosphatase activity was significantly decreased in …the liver of low dose arsenic-treated animals; however, significant rise in its activity was observed in high dose group. As compared with vehicle control, treatment also caused significant dose-dependent reductions in SDH, alkaline phosphatase and acid phosphatase activities in the kidney of mice. Vitamin E cotreatment as well as, 30 d withdrawal of arsenic trioxide treatment with or without vitamin E caused significant amelioration in arsenic-induced toxicity in mice. Administration of vitamin E during withdrawal of treatment also caused significant amelioration as compared from only withdrawal of the treatment. It is concluded that vitamin E ameliorates arsenic-induced toxicities in the liver and kidney of mice. Show more

Keywords: arsenic toxicity, mice, oral administration, amelioration

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 447-453, 2004

Authors: LI, Ning | CHEN, Xiao-yong | SHEN, Lang | LI, Yuan-yuan | CAI, Yue-wei

Article Type: Research Article

Abstract: The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dramatically change genotypic frequencies at some loci of P. annua populations. Significant deviations from Hardy-Weinberg equilibrium were observed on loci Fe-1 and Me due to the excess of heterozygote in some populations. (2) The effective number of alleles per locus, and the observed and …expected heterozygosity were higher in the pollution series than in the clear control site (Botanic Park population), but the increase was not related with the pollution extent. (3) Most genetic variation was found within populations, and only 6.21% was among populations of the polluted series. Slightly higher differentiation (F_{ST} =7.98%) was observed when the control population was included. (4) The calculated gene flow (Nm) is 2.8841 per generation. The mean of genetic identity is 0.9864 and the genetic distance average to 0.0138. Show more

Keywords: genetic composition, traffic pollution, allozyme analysis, Poa annua L

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 454-457, 2004

Authors: WANG, Shu-guang | LIN, Xian-gui | YIN, Rui | HOU, Yan-lin

Article Type: Research Article

Abstract: The effect of inoculation with arbuscular mycorrhiza (AM) fungi (Acaulospora lavis) on the degradation of di (2-ethylhexyl) phthalate (DEHP) in soil was studies. Cowpea plants (Pigna sinensis) were used as host plants and grown in a specially designed rhizobox. The experimental results indicated that, both in sterile and non-sterile soil, mycorrhizal colonization rates were much higher in the mycorrhizal plants than in the non-mycorrhizal plants. Addition of 4 mg/kg DEHP slightly affected mycorrhizal colonization, but the …addition of 100 mg/kg DEHP significantly decreased mycorrhizal colonization. DEHP degradation in the mycorrhizosphere (Ms) and hyphosphere (Hs), especially in the Hs, increased after inoculation with Acaulospora lavis. It is concluded that mycorrhizal hyphae play an important role in the plant uptake, degradation and translocation of DEHP. The mechanism might be attributed to increased numbers of bacteria and actinomycetes and activity of dehydrogenase, urease and acid phosphatase in the Ms and Hs by mycorrhizal fungi. Show more

Keywords: AM fungi, inoculation, DEHP, concentration, degradation

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 458-461, 2004

Authors: LIN, He | GAO, Xiang | LUO, Zhong-yang | GUAN, Shi-pian | CEN, Kefa | HUANG, Zhen

Article Type: Research Article

Abstract: In this paper, removal of NOx (namely DeNOx) from flue gas by radical injection combined with NaOH solution (26% by weight of NaOH in water) scrubbing was investigated. The experimental results showed that the steady streamer corona occurs through adjusting the flow rate of the oxygen fed into the nozzles electrode. The vapor in the oxygen has influence on the V-I characteristics of corona discharge. Both HNO_2 and HNO_3 come into being …in the plasma reactor and the DeNOx efficiency in the plasma reactor is more than 60%. The overall DeNOx efficiency of the whole system reaches 81.7% when the NaOH solution scrubbing is collaborated. Show more

Keywords: radical, plasma reactor, DeNOx process, absorb

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 462-465, 2004

Authors: Das, Biplob | Khan, Yusuf Sharif Ahmed | Das, Pranab

Article Type: Research Article

Abstract: Nutrient loadings were measured for surface seawater and bottom sediments of semi-intensive and improved extensive shrimp culture pond, adjacent estuary, and fallow land in the south-east coastal region of Bangladesh during August, 2000 – January, 2001 to evaluate the impact of shrimp culture. The mean levels of nutrients found in the pond surface water were 108.780 mg/L for CaCO_3, 0.526 mg/L for NH<FORMULA>_4^+ -N, 3.075 wt% for organic carbon, 7.00 mg/L for …PO_4 -P, 5.57 mg/L for NO_3 -N, and 7.33 mg/L for chlorophyll-a. The maximum mean value of H_2 S (0.232 mg/L) was found in estuarine water. Nutrients loading were found to be decreased with distance from the shrimp farm discharge unit in estuarine water. The mean level of organic matter, total nitrogen, and organic carbon were found in higher concentrations in sediments of cultured pond compared to bottom soil of adjacent fallow land at the same elevation. Extractable Ca values were found in higher concentration (550.33 ppt) in adjacent fallow land, as; the shrimps for molting in shrimp ponds use extractable Ca. The relation between seawater H_2 S value and sediment pH (r = -0.94); sediment organic carbon and sediment pH values (r = -0.76), sediment total nitrogen and sediment pH (r = -0.74) were found to be highly negatively correlated. Whereas the relation between seawater H_2 S value and sediment total nitrogen (r = 0.92), water NH_4^+ -N and sediment pH (r = 0.66) were found to be positively correlated. The results revealed that load of nutrients at eutrophic level in estuarine water, and decrease of soil pH; leading to acid sulphate soil formation indicates a negative impact of shrimp culture. Show more

Keywords: environment, eutrophication, impact, nutrients, shrimp culture

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 466-470, 2004

Authors: LIU, Fu-qiang | CHEN, Jin-long | CHENG, Xiu-mei | GE, Jun-jie | LI, Ai-min | ZHANG, Quan-xing

Article Type: Research Article

Abstract: An aminated hypercrosslinked macroporous polymeric adsorbent was synthesized and characterized. Adsorption isotherms for 1-amino-2-naphthol-4-sulfonic acid (1, 2, 4-acid) and 2-naphthol obtained from various binary adsorption environments can be well fitted by Freundlich equation, which indicated a favorable adsorption process in the studied range. Adsorption for 1, 2, 4-acid was an endothermic process in comparison with that for 2-naphthol of an exothermic process. 2-naphthol molecules put a little influence on the adsorption capacity …for 1, 2, 4-acid. However, the adsorption to 1, 2, 4-acid depressed that to 2-naphthol in a large extent for the stronger electrostatic interaction between 1, 2, 4-acid and adsorbent. The predominant mechanism can be contributed to the competition for adsorption sites. And the simultaneous environment was confirmed to be helpful to the selective adsorption towards 1,2,4-acid based on the larger selectivity index. Show more

Keywords: aminated hypercrosslinked macroporous polymeric adsorbent, 1, 2, 4-acid, 2-naphthol, competitive adsorption

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 471-475, 2004

Authors: SHI, Lei | WANG, Bao-zhen | CAO, Xiang-dong | Wang, Jin | LEI, Zhi-hong | WANG, Zhi-ren | LIU, Zheng-ying | LU, Bing-nan

Article Type: Research Article

Abstract: The operational performance of a full-scale subsurface-flow constructed wetland, which treated the mixed industrial and domestic wastewater with BOD_5 /COD mean ratio of 0.33 at Shatian, Shenzhen City was studied. The constructed wetland system consists of screens, sump, pumping station, and primary settling basin, facultative pond, first stage wetland and secondary stage wetland. The designed treatment capacity is 5000 m^3 /d, and the actual influent flow is in the range of < …2000 to > 10000 m^3 /d. Under normal operational conditions, the final effluent quality well met the National Integrated Wastewater Discharge Standard (GB 8978-1996), with the following parameters (mean values): COD 33.90 mg/L, BOD_5 7.65 mg/L, TSS 7.92 mg/L, TN 9.11 mg/L and TP 0.56 mg/L. Seven species of plants were selected to grow in the wetland: Reed, Sweetcane flower Silvergrass, Great Bulrush, Powdery Thalia and Canna of three colours. The growing season is a whole year-round. The seasonal discrepancy could be observed and the plants growing in the wetland are vulnerable to lower temperature in winter. The recycling of the effluent in the first stage of the wetland system is an effective measure to improve the performance of the wetland system. The insufficient DO value in the wetland system not only had significant effect on pollutants removal in the wetland, but also was unfavourable to plant growth. The recycling of effluent to the inlet of wetland system and artificial pond to increase DO value of influent to the wetland is key to operate the subsurface constructed wetland steadily and effectively. Show more

Keywords: subsurface-flow constructed wetland, operational performance, marsh plants, pre-treatment, facultative pond

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 476-481, 2004

Authors: HE, Fei | JIA, Zhi-qian | PENG, Yue-lian | WANG, Pei-jing | LIU, Zhong-zhou

Article Type: Research Article

Abstract: Al_{13} or Al_b is usually regarded as the most efficient species of polyaluminum chloride (PAC), the performance flocculant for water treatment. This paper was intended to report a new method to synthesize PAC with high content Al_b , by using the membrane reactor. NaOH solutions were managed to permeate slowly through the micropores of ultrafiltration membrane into AlCl_3 solutions under the suitable transmembrane pressure (TMP). …Meanwhile NaOH drops size was limited to nano-scale, resulting in dramatical reduction of the characteristic diffusion time and great increment of contact interface between the strong base and Al ions in solution to favor the formation of Al(OH)_4^- , the precursor of Al_{13} , so little precipitates and much Al_b are produced. When the initial concentration of AlCl_3 /NaOH is 0.40/2.0 (mol/L), MWCO=10000, TMP=0.0085 MPa, T=305K and B (molar ratio of OH^- /Al^{3+} )=2.25, the quantity of Al_b attains about 80%. The results of ^{27} Al-NMR determination show that the Al_{13} content is equal to Al_b content. And our PAC product has shown better flocculation effects than the commercial product. Show more

Keywords: membrane reactor, polyaluminum chloride

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 482-486, 2004

Authors: SUI, Hong | LI, Xin-Gang | XU, Shi-Min

Article Type: Research Article

Abstract: Trichloroethylene (TCE), a common groundwater pollutant, was cometabolized by microorganisms in the presence of toluene as a growth substrate. The effect of concentrations of toluene and TCE and temperature on biodegradation was discussed. Acclimated microorganisms degraded TCE after a lag period of 5 to 22 h depending on toluene concentrations. Approximately 60%, 90% and 64% of TCE were degraded at toluene to TCE concentration ratios of 23:1, 115:1 and 230:1, respectively. At a TCE concentration of …1.46 μg/ml, 80% of TCE and 98.4% of toluene were removed. But less degradation of TCE and toluene was observed when TCE concentration was above 48.8 μg/ml. The lag time of TCE decreased and the TCE biodegradation rates increased with the increase of temperature. Show more

Keywords: cometabolism, microbial degradation, toluene, trichloroethylene

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 487-489, 2004

Authors: PENG, Jian | WANG, Yang-lin | JING, Juan | LI, Wei-feng | DING, Yan

Article Type: Research Article

Abstract: Littoral zone is a special land/landscape type. As an important kind of land resource in support, the use of littoral zone is vital to eastern coastal areas in China. And the research on littoral zone relates to the key theory of landscape ecology. Based on the theory of landscape ecology, the littoral zone was divided into four types: mud flat, sand beach, bench, and biological flat. The distribution of each type in China is pointed out. As a …typical open system, littoral zone has six landscape ecological characteristics: (1) high sensitivity to disturbance; (2) distinct edge effect; (3) spatial aggregation of natural resources; (4) frequently spatial oscillation; (5) obviously spatial heterogeneity; and (6) noticeably spatial differentiation. Some proposals are also put forward on the land use and development of littoral zone for environmental protection and environmental management. Show more

Keywords: landscape eco-environment, littoral zone, China

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 490-496, 2004

Authors: Mottaleb, M.A. | Abedin, M.Z. | Islam, M.S.

Article Type: Research Article

Abstract: A simple, rapid, and reproducible method is described employing solid-phase extraction (SPE) using dichloromethane followed by gas chromatography (GC) with flame ionization detection (FID) for determination of volatile organic compound (VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene (BTEXC) in the sample collected from the surface or 15 cm depth of water. Two-hundred ml of n-hexane-pretreated and filtered water samples were …applied directly to a C_{18} SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0.104 to 0.372 μg/ml. The highest concentration of benzene was found as 0.372 μg/ml with a relative standard deviation (RSD) of 6.2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C_{18} adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water.Average recoveries exceeding 90% could be achieved for cumene at 4°C with a 2.7% RSD. Show more

Keywords: solid-phase extraction, river water, environmental aalysis, VOC recoveries

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 497-501, 2004

Authors: LI, Jing-ying | ZHANG, Jing

Article Type: Research Article

Abstract: The atmospheric precipitation plays an important role in influencing the river chemistry of the Dongjiang River. The atmospheric contribution to river water is estimated by reference to Cl concentration called Cl_{ref} . The Cl_{ref} of 41.97 μmol/L represents the highest chloride concentration of the rainwater inputs to river water, thus sea salts are responsible for total Cl concentration of the Dongjiang River. According to the principal compositions of precipitation and …river water, we propose two approaches-sea salt correction and precipitation correction in order to correct the contribution proportions of atmospheric precipitation on the solutes and to calculate chemical weathering rate. The results reflected that the atmospheric contribution ratios fluctuate from ∼5% to ∼20% of TDS (total dissolved solids) in the Dongjiang River. As compared with the other world watersheds, the lower dissolved ion contents and high runoff may result in the obvious influence of precipitation on river chemistry in the Dongjiang basin. The major elemental chemistry is mainly controlled by silicate weathering, with the anion HCO_3^- and cation Ca^{2+} and Na^+ dominating the major compositions in this basin. The estimated chemical weathering rate of 15.78–23.48 t/(km^2 ˙ a) is only 40%–60% of a global average in the Dongjiang basin. Certainly, the estimated results are still under correction gradually because the effect of human activities on the precipitation chemistry has never been quantified in detail. Show more

Keywords: Dongjiang River, river solutes, precipitation chemistry, atmospheric inputs, chemical weathering rate

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 502-508, 2004

Authors: YANG, Sheng-tian | YANG, Zhi-feng | MAO, Xian-qiang | ZHU, Qi-jiang

Article Type: Research Article

Abstract: Employing remote sensing method to interpret the building volumetric ratio and aerosol status in Guangzhou, China. The relation between them and identified characteristics of their spatial distribution was analyzed. Results showed that building density and aerosol status are strongly correlated. It is indicated that the resistance of building to aerosol diffusing is one of factors influencing air pollution in urban area. On the basis of calculated results, building voluminous ratio of 5.6 is taken as the …threshold impacting on aerosol diffusing, so the building voluminous ratio of Guangzhou should be limited to less than 5.6 in order to alleviate air pollution. Show more

Keywords: remote sensing, aerosol, building voluminous ratio, air pollution

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 509-512, 2004

Authors: JIANG, Xia | JIN, Xiang-can | YAN, Chang-zhou | Yediler, Ayfer | OU, Zi-qing | Kettrup, Antonius

Article Type: Research Article

Abstract: Advanced closed chamber system was used to study the fate of phenanthrene (3-rings PAHs) in the presence of linear alkylbenzene sulphonates (LAS). The results showed mineralization and metabolism of phenanthrene are fast in the "culture solution – lava – plant – air" model ecological system. The distribution proportions of applied ^{14} C-activity in this simulative ecological system were 41%–45%, 14% to 10% and 1% in plant, lava and culture solution respectively, and 18% to 29%, …11% to 8% recovered in the forms of VOCs and CO_2 . Main parts of the applied 14C-activity exist in two forms, one is polar metabolites (25%) which mainly distribute in the root (23%), the other is unextractable part (23%) which have been constructed into plant root (8.98%), shoot (0.53%) or bonded to lava (13.2%). The main metabolites of phenanthrene were polar compounds (25% of applied 14C-activity), and small portion of ^{14} C-activity was identified as non-polar metabolites (6% of applied ^{14} C-activity) and apparent phenanthrene (1.91% of applied ^{14} C-activity). Phenanthrene and its metabolites can be taken up through plant roots and translocated to plant shoots. The presence of LAS significantly increased the the concentration of ^{14} C-activity in the plant and production of VOCs, at the same time it decreased the phenanthrene level in the plant and the production of CO_2 at the concentration of 200 mg/L. Show more

Keywords: phenanthrene, LAS, plant, closed chamber systems

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 513-519, 2004

Authors: XI, Bei-dou | HUANG, Guo-he | QIN, Xiao-sheng | LIU, Hong-liang

Article Type: Research Article

Abstract: In order to understand the key mechanisms of the composting processes, the municipal solid waste (MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from the viewpoint of microbial kinetics was analyzed. Through experimentation with advanced composting reactor under controlled composting conditions, several equations were worked out to simulate the degradation rate of the substrate. The equations showed that the degradation rate was controlled by concentration …of microbes in the first stage. The degradation rates of substrates of inoculation Run A, B, C and Control composting systems were 13.61 g/(kg ˙ h), 13.08 g/(kg ˙ h), 15.671 g/(kg ˙ h), and 10.5 g/(kg ˙ h), respectively. The value of Run C is around 1.5 times higher than that of Control system. The decomposition rate of the second stage is controlled by concentration of substrate. Although the organic matter decomposition rates were similar to all Runs, inoculation could reduce the values of the half velocity coefficient K_m and could be more efficient to make the composting stable. Particularly. For Run C, the decomposition rate is high in the first stage, and K_m is low in the second stage. The results indicated that the inoculation was efficient for the composting processes. Show more

Keywords: municipal solid waste, inoculation complex microbial community, oxygen consumption, two stages kinetics equations

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 520-524, 2004

Authors: KE, Shui-zhou | SHI, Zhou | ZHANG, Tong | FANG, Herbert H. P.

Article Type: Research Article

Abstract: A synthetic wastewater containing phenol as sole substrate was treated in a 2.8 L upflow anaerobic sludge blanket (UASB) reactor at ambient temperature. The operation conditions and phenol removal efficiency were discussed, microbial population in the UASB sludge was identified based on DNA cloning, and pathway of anaerobic phenol degradation was proposed. Phenol in wastewater was degraded in an UASB reactor at loading rate up to 18 gCOD/(L ˙ d), With a 1:1 recycle ratio, at …26 ± pH 7.0–7.5. An UASB reactor was able to remove 99% of phenol up to 1226 mg/L in wastewater with 24 h of hydraulic retention time (HRT). For HRT below 24 h, phenol degradation efficiency decreased with HRT, from 95.4% at 16 h to 93.8% at 12 h. It further deteriorated to 88.5% when HRT reached 8 h. When the concentration of influent phenol of the reactor was 1260 mg/L (corresponding COD 3000 mg/L), with the HRT decreasing (from 40 h to 4 h, corresponding COD loading increasing), the biomass yields tended to increase from 0.265 to 3.08 g/(L ˙ d). While at 12 h of HRT, the biomass yield was lower. When HRT was 12 h, the methane yield was 0.308 L/(gCOD removed), which was the highest. Throughout the study, phenol was the sole organic substrate. The effluent contained only residual phenol without any detectable intermediates, such as benzoate, 4-hydrobenzoate or volatile fatty acids (VFAs). Based on DNA cloning analysis, the sludge was composed of five groups of microorganisms. Desulfotomaculum and Clostridium were likely responsible for the conversion of phenol to benzoate, which was further degraded by Syntrophus to acetate and H_2 /CO_2 . Methanogens lastly converted acetate and H_2 /CO_2 to methane. The role of epsilon-Proteobacteria was, however, unsure. Show more

Keywords: ambient temperature, anaerobic degradation, phenol, UASB, DNA, wastewater

Citation: Journal of Environmental Sciences, vol. 16, no. 3, pp. 525-528, 2004