Journal of Environmental Sciences - Volume 16, issue 2

Authors: LIU, Guang-shen | XU, Dong-mei | WANG, Li-ming | LI, Ke-bin | LIU, Wei-ping

Article Type: Research Article

Abstract: The main effects of pollutions including acid rain, Cu^{2+} , atrazine and their combined products on the activities of urease, invertin, acid phosphatase and catalase were studied by means of orthogonal test. The results showed that H^^+ and Cu^{2+} had significant influence on the activities of four enzymes and the ability of their inhibiting followed the order: H^+ � Cu^{2+} . Al^{3+} …and atrazine only had litter effects on the activity of urease and phosphatase, respectively. Furthermore, interaction analysis revealed that Cu^{2+} -H^+ affected on the activity of acid phosphatase significantly and antagonism on invertin and urease, Cu^{2+} -atrazine only exhibited the synergism on the activity of acid phosphatase. But atrazine-H^+ had non-interaction within the investigated concentration range. Among four enzymes, acid phosphatase was the most sensitive one to the contaminations. Show more

Keywords: combined pollution, orthogonal test, hydrolase, activity

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 177-180, 2004

Authors: Muttamara, S. | Leong, Shing Tet

Article Type: Research Article

Abstract: This study was conducted to assess the occupational exposure and its health impact on the chromium alloy workers. Environmental and biological monitoring, noise and audiometry measurements were done to evaluate the exposure levels in the factory. A total of 112 non-smoking workers were monitored from July 2001 to August 2002. The results showed that most of the chromium and lead exposures in the factory were below the ACGIH-TWA of 50 μg/m^3 for chromium (VI) …and OSHA-PEL of 50 μg/m^3 for lead. The highest chromium (7.25 ± 0.16 μg/m^3 ) and lead (14.50 ± 0.29 μg/m^3 ) concentrations were measured in the vibro room. The results indicated that elevated concentrations of chromium and lead were found in both blood and urine samples especially in those areas which were characterized by poor ventilation. The metal contents in blood and urine samples were significantly correlated with airborne metal concentrations in the factory. The result demonstrated that blood and urinary levels among workers were associated with increasing age and duration of exposure. The background noise level of the factory ranged from 67.6 to 89.2 dBA and was frequently higher than the threshold limit value for noise (90 dBA). According to the audiometric test, the exposed workers showed signs of noise-induced hearing loss. Noise at work continued to be an important factor to hearing loss among exposed workers. In our statistical analysis, a significant hearing loss was established on age effect and year of exposure among the workforce. Show more

Keywords: chromium and lead exposure, electroplating, environmental and biological monitoring, audiometry measurement

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 181-186, 2004

Authors: XIA, Xiang-ao | LIANG, Feng | WANG, Ming-xing

Article Type: Research Article

Abstract: TOMS/Al data with nearly 20 years are utilized in the paper to evaluate dust activities in North China. Combined with simultaneous NCEP reanalysis climate data, climate effects on dust activities are assessed. The results showed that the whole North China suffers impact by dust aerosols, with three centers standing out in TOMS/Al spring average map that are western three basins, which are characterized by lower annual precipitation and elevation. Gobi deserts in Mongolia Plateau do not …attain higher TOMS/Al value due to cloud contamination and relative higher elevation. Spring is the season with the highest TOMS dust aerosol index; within the western three basins, high dust aerosol index appears in both spring and summer, especially in Tarim Basin. Wind speed in spring and precipitation in previous rainy season play important roles in controlling dust activities, higher wind speed and less precipitation than the normal are in favor of dust activities in spring. Temperature in spring and previous winter also affect dust activity to a certain extent, but with contrary spatial distribution. Temperature in winter exert effect principally in west part, contrarily, temperature effect in spring is mainly shown in east part. Both of them have negative correlation with dust activity. Show more

Keywords: TOMS/Al, NCEP climate data, dust activity, correlation analysis

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 187-190, 2004

Authors: YANG, Sen | LIU, Zhong-zhou

Article Type: Research Article

Abstract: The effect of additives CaCl_2 and CaCl_2 /H_2 O on the properties of polyacrylonitrile (PAN) ultrafiltration (UF) membranes prepared by phase inversion process was studied. The dissolving capacity of the casting solution for CaCl_2 was enhanced by the addition of H_2 O. The membranes are characterized in terms of the pure water flux and molecular weight cut-off (MWCO). The addition of CaCl_2 or …CaCl_2 /H_2 O to the casting solution increases the resulting membrane permeability. Show more

Keywords: polyacrylonitrile, CaCl_2, H_2O, dissolving capacity, ultrafiltration membranes

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 191-193, 2004

Authors: Mahadevaswamy, M. | Murthy, B.M. Sadashiva | Girijamma, A.R.

Article Type: Research Article

Abstract: The present study deals with the performance evaluation of the UASB reactor under varied organic loadingrate (OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0.8 mm at OLR of 1.72 kgCOD/(m^3 ˙ d), which reached maximum size of about 1.0 to 1.2 mm at OLR of 2.1 kg COD/(m^3 ˙ d). At the end of …initial OLR of 1.0 kg COD/(m^3 ˙ d) the VSS concentration was 12.86 g VSS/L, which got increased to 38.05 g VSS/L at the end of an OLR 2.1 process. Many times the pH observed was between 6.5 and 7.8, which is more favorable for any anaerobicprocess. It is also found that pH within the reactor increases along with the height of reactor. The total maximum biogas production was found to be 0.40 L/g COD removals at OLR of 2.1 kg COD/(m^3 ˙ d) and the maximum BOD removal at this stage was observed to be 90%. Show more

Keywords: UASB, biogas, anaerobic digestion, sludge loading rate, organic loading rate

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 194-198, 2004

Authors: HAO, Fang-hua | CHANG, Ying | NING, Da-tong

Article Type: Research Article

Abstract: Land degradation is a consequence stemming from both natural processes and social economic activities. On the bases of analyzing general situation of agricultural land degradation in China, the monetary estimating methods such as market value method and shadow engineering method were used to quantitatively assess the economic loss resulting from land deterioration. Results showed that the economic loss in 1999 was 326.81 billion RMB Yuan, which accounted for 4.1% of GDP in the same year of …China. If taking five items namely farmland conversion, soil erosion, salinization, decline in reservoir functions, and siltation in waterways and, comparing withthat in 1992, the percentage of economic loss to GDP has increased by 1.5 in the only 7 years. Show more

Keywords: agricultural land, degradation, economic loss, estimating method , China

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 199-203, 2004

Authors: HUANG, Jun | YU, Gang | YANG, Xi | ZHANG, Zu-lin

Article Type: Research Article

Abstract: Polychlorinated diphenyl ethers (PCDEs) have received more and more concerns as a category of potential persistent organic pollutants (POPs). Modeling its environmental fate and exposure assessment require a number of fundamental physico-chemical properties. However, the experimental data are currently limited due to the difficulty in analysis caused by the complexity of PCDE congeners. As an alternative, the quantitative structure property relationship (QSPR) approach could be used. In this paper, twelve kinds of …molecular connectivity indices (MCIs) of all 209 possible molecular structure patterns of PCDEs were calculated. Based on 106 PCDEs with three observed physico-chemical properties-vapour pressure (P^o_L ), aqueous solubility (S_w ) and n-octanol/water (K_{ow} ) and their MCIs data, a series of QSPR equations were established using multiple linear regression (MLR) method. As a result, three equations with best performance were selected mainly from the view of high regression coefficient (R)and low standard error (SE). All of them showed significant relationship and high accuracy. With these equations the properties of other 103 patterns of PCDEs without the reported observed values were predicted. Further more,three partition properties for PCDE congeners-Henry's Law constants (H), partition coefficients between gas/water (K_{gw} ) and gas/n-octanol (K_{go} ) were calculated according to the internal relationship among these six properties. These observed and predicted values, in contrast with the criteria listed in the Stockholm treaty about POPs which has been signed by more than ninety countries in May 2001, illustrated that most of PCDEs congeners are potential persistent organic pollutants. As all descriptors/predictors are derived just from the molecular structure itself and without the import of any empirical parameters, this method is impersonal and promising for the estimation of physico-chemical properties of PCDEs. Show more

Keywords: PCDEs, POPs, QSPR, molecular connectivity indices

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 204-207, 2004

Authors: LI, Yan-hui | DI, Ze-chao | LUAN, Zhao-kun | DING, Jun | ZUO, Hua | WU, Xiao-qing | XU, Cai-Lu | WU, De-hai

Article Type: Research Article

Abstract: Carbon nanotubes prepared by catalytic chemical vapor deposition of hydrocarbon at 650°C show good adsorption capability of Pb^{2+} , Cu^{2+} and Cd^{2+} ions from aqueous solution after oxidized with concentrated nitric acid at 140°C for 1 h. The specific surface area and particle size distribution of the as-grown and oxidized CNTs were studied by BET method and laser particle analyzer. Three kinetic models, that is, first-, pseudo …second- and second-order, were used to investigate the adsorption data and the pseudo second-order model can represent the experimental data better than two others. The equilibrium data fitted well with the Langmuir model and showed the following adsorption order: Pb^{2+} > Cu^{2+} > Cd^{2+} . Show more

Keywords: carbon nanotubes, heavy metals, adsorption

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 208-211, 2004

Authors: Lam, K.S. | Cheng, Z.L. | Kot, S.C. | Tsang, C.W.

Article Type: Research Article

Abstract: An one-year of sampling aerosol program was carried out during the period of April 1995 to April 1996 at coastal region, Cape D'Aguilar, in Hong Kong. The trace element composition of aerosol particles (TSP and PM_{10} ) were measured and analyzed by using the Instrumental Neutron Activation Analysis (INAA) and Inductive Couple Plasma-Mass Spectrometry (ICP-MS) techniques. The results showed that the polluted elements such as: V, Zn, As, Pb, Cd, Sb, I, Se, Bi, with …high enrichment factor (E. F) values, are derived from anthropogenic sources, while Sc, Al, Fe, Mn, Sm, La, Sr are less than 10 in E. F, these elements are related the crust and soil. The concentration of the trace elements are present seasonal variation i.e. summer low and winter high, whereas the V or noncrustal V(V*) present summer high and winter low, this phenomenon might be explained by local or regional oil combustion sources. Use three type of elemental ratio, e.g. La/Sm, Mn*/V* and Bi/Al indicate that both TSP and PM_{10} of La/Sm ratios are mainly related to soil and dust, Mn*/V* are probably represent fossil combustion and Bi/Al are possibly associated with refuse incineration, ferromanganese alloys and aluminum production. The varimax rotation factor analysis for trace elements was performed. By means of the absolute principal component analysis (APCA) and multiple regression, the contribution of trace elements to possible sources and overall means of trace elements were estimated. The results showed that the present station is impacted by the anthropogenic species, although the quantities are different during the summertime and wintertime. Show more

Keywords: TSP, PM_{10}, trace elements, enhancement factor, element ratios, seasonal variation, factor analysis

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 212-221, 2004

Authors: SHEN, Xue-you | LU, Ying-ying | ZHU, Li-zhong | LU, Shu-yu

Article Type: Research Article

Abstract: Organobentonites synthesized by replacing the metal ions in bentonite with cetyltrimethylammonium (CTMA) or tetramethylammonium cation (TMA) were investigated for their behaviors to sorb benzene, toluene, p-xylene from water. The results served to distinguish the sorption mechanisms (adsorption or partition) of the two types of organobentonites. Bentonites modified with short-chain alkyl functional groups (e. g., TMA) sorb organic contaminants primarily by an adsorption process, in which the sorbed amount decreases with increasing steric …hindrance of the organic compound and the process exhibits a competitive effect because of steric hindrance in multi-solute systems. In contrast, the sorption of contaminants to organobentonites modified with long-chain alkyl groups (e. g., CTMA) occurs by partition process without exhibiting a competitive effect, and the additional organic compounds may induce a cosorptive effect. In the latter case, the measured distribution coefficients of organic compounds between organobentonites and water (log K_d ) are positively correlated with the octanol-water partition coefficients of the compounds (logK_{ow} ) and the sorption process exhibits no competitive effect in multi-solutesystems. Show more

Keywords: organobentonite, organic compounds, adsorption, partition

Citation: Journal of Environmental Sciences, vol. 16, no. 2, pp. 222-225, 2004