Journal of Environmental Sciences - Volume 18, issue 4

Authors: XU, Xiang-hua | SHI, Ji-yan | CHEN, Ying-xu | XUE, Sheng-guo | WU, Bei | HUANG, Yu-ying

Article Type: Research Article

Abstract: Phytolacca acinosa Roxb. (P. acinosa) is a recently discovered manganese hyperaccumulator plant from southern China. It is a good candidate for phytoremediation of manganese(Mn) polluted soil for its high biomass and fast growth. Knowledge of the tissue localization and identification of heavy metals can provide essential information on metal toxicity and bioaccumulation mechanisms. Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) microprobe was used in this study to investigate the cellular distributions of Mn …and other elements in root, stem, leaf, petiole and midrib ofP. acinosa. The highest Mn content was found in the vascular tissues of root, stem, petiole and midrib. Cortex in root played a key role in Mn absorption and Mn was limited in the vascular bundle during the process of transportation in stem. Moreover, Mn content in leaf epidermis was higher than that in mesophyll, which suggested that the sequestration of Mn in leaf epidermis might be one of the detoxification mechanisms of P. acinosa. The significance of other elemental (such as P, S, K, Ca, Fe, Zn and Cu) distribution patterns and the correlation with Mn were also discussed. Show more

Keywords: hyperaccumulator, Phytolacca acinosa Roxb., manganese, element distribution, SRXRF

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 746-751, 2006

Authors: FANG, Yun-ting | ZHU, Wei-xing | MO, Jiang-ming | ZHOU, Guo-yi | GUNDERSEN, Per

Article Type: Research Article

Abstract: Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions. Results showed that the mature monsoon evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine (Pinus massoniana) and pine-broadleaf mixed forests, both originated from the 1930's clear-cut and …pine plantation. Mature forests had greater extractable inorganic N pool, lower N retention capacity, higher inorganic N leaching, and higher soil C/N ratios. Mineral soil extractable NH_4^+ -N and NO_3^- -N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except NH_4^+ -N in the mature forest. In contrast, inorganic N (both NH_4^+ -N and NO_3^- -N) in soil 20-cm below the surface was significantly elevated by the N additions. From 42% to 74% of N added was retained by the upper 20 cm soils in the pine and mixed forests, while 0%–70% was retained in the mature forest. Our results suggest that land-use history, forest age and species composition were likely to be some of the important factors that determine differing forest N retention responses to elevated N deposition in the study region. Show more

Keywords: N deposition, N saturation, extractable inorganic N, soil solution inorganic N, subtropical China

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 752-759, 2006

Authors: FANG, Hua | YU, Yun-long | WANG, Xiao | SHAN, Min | WU, Xiao-mao | YU, Jing-quan

Article Type: Research Article

Abstract: The dissipation of chlorpyrifos in pakchoi-vegetated soil was investigated in the summer and autumn in a greenhouse and field, respectively. The dissipation of chlorpyrifos in pakchoi-grown soil was comparatively described by fitting the residue data to seven models (1st-order, 1.5th-order, 2nd-order, RF 1st-order, RF 1.5th-order, RF 2nd-order, and bi-exponential or two-compartment models). Statistical analysis was performed using the SPSS 11.5 statistical package. The bi-exponential model was selected as the optimal model according …to the coefficient of determination r^2 . The dissipation half-lives (DT_{50} ) of chlorpyrifos in pakchoi-vegetated soil at the recommended dose in the summer and autumn, calculated by the bi-exponential model, were 0.6 and 1.2 d in a greenhouse, 0.4 and 1.0 d in a field, respectively; the corresponding values at double dose were 1.2 and 2.1 d in a greenhouse, 0.5 and 1.3 d in a field, respectively. The kinetic data indicate the dissipation of chlorpyrifos in pakchoi-grown soil in a greenhouse is slower than that in a field, and dissipates slower in the autumn than in the summer. Show more

Keywords: chlorpyrifos, dissipation, greenhouse, kinetic model, soil

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 760-764, 2006

Authors: HAN, Yong-zhong | JIANG, Li-yu | CHEN, Jin-long | ZHANG, Quan-xing

Article Type: Research Article

Abstract: Thermal regeneration ofhypercrosslinked polymeric adsorbent (HPA) was performed at 67°C. Experiments were carried out using a multimode microwave oven operating at 2450 MHz and a thermostatic water bath so as to compare the effect of the different heating mechanisms on the regeneration efficiency of the HPA saturated with nitrophenols. The temperature rise action of the heterogeneous regeneration system under microwave irradiation was described. Additionally, a complete structure and chemical characterization of the …regenerated HPA was also carried out in order to study the influence of the subsequent regeneration cycles on the structure and the adsorption capacities of the adsorbents. Structure characterization of the regenerated HPA was accomplished by means of the analysis of FTIR spectra. Show more

Keywords: polymeric adsorbent, microwave irradiation, adsorption, structure

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 765-770, 2006

Authors: ZHAN, Man-jun | YANG, Xi | XIAN, Qi-ming | KONG, Ling-ren

Article Type: Research Article

Abstract: The aqueous photodegradation of bisphenol A (BPA) in the presence of Fe(III)-oxalate complexes (Fe(III)-Ox), which are common compositions of natural water, was investigated in this study. BPA underwent rapid indirect photolysis in Fe(III)-Ox solution under simulated solar irradiation, proceeding pseudo-first-order kinetics. The photolysis rate increased with decreasing pH or initial BPA level and increasing Fe(III)/oxalate concentration ratio. Hydroxyl radicals (·OH), which were generated from the photochemical processes of Fe(III)-Ox complexes and contributed …to the photooxidation of BPA, were determined by molecular probe and electron spin resonance (ESR) methods with the steady-state concentration of 2.56 × 10^{-14} mol/L. Superoxide anion radical (O_2^{·-} ) was considered as the precursor of ·OH and qualitatively determined by adding nitro blue tetrazolium as well as ESR experiments. Based on the structural analysis of the intermediate photoproducts of BPA in Fe(III)-Ox complexes solution, the possible degradation pathways of BPA were proposed, involving ·OH addition, alkyl scission and alky oxidation. The results indicate that the photochemical reactivity of Fe(III) may affect the environmental fate of BPA in natural water significantly. Show more

Keywords: bisphenol A, Fe(III)-oxalate complexes, photooxidation, reactive oxygen species

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 771-776, 2006

Authors: DONG, Jun | LI, Fang-bai | LAN, Chong-yu | LIU, Cheng-shuai | LI, Xiao-min | LUAN, Tian-gang

Article Type: Research Article

Abstract: To understand the degradation of endocrine disrupting chemicals (EDCs) in natural environment with existence of iron oxides and carboxylic acids, the dependence ofbisphenol A (BPA) photodegradation on the initial concentration ofoxalate (C_{ox} ) in lepidocrocite (γ-FeOOH) aqueous suspension was investigated under both UV and visible lights in this study. Lepidocrocite powder was home-prepared by a hydrothermal process. It was found that BPA degradation was promoted greatly in the presence of oxalate …owing to the formation of lepidocrocite-oxalate complex. And there was an optimal C_{ox} , which was 2.0 and 2.4 mmol/L, under UV and visible lights, respectively. The first-order kinetic constant, k value increased 38 times from 0.17 × 10^{-2} min^{-1} in the absence of oxalate to 6.39 × 10^{-2} min^{-1} in the presence ofoxalate with an optimal C_{ox} (2.0 mmol/L) under UV irradiation, and almost 306 times from 0.02 × 10^{-2} min^{-1} in the absence ofoxalate to 6.11 × 10^{-2} min^{-1} in the presence of oxalate with an optimal C_{ox} (2.4 mmol/L) under visible irradiation. The BPA degradation rate increased and the first-order kinetic constants decreased with the increase in BPA initial concentration. The dependence of the variation of pH value, total-Fe and Fe^{2+} during the photoreaction on C_{ox} was also investigated. The pH value increased obviously with the reaction time. Total-Fe increased dramatically at the first 5 min and then decreased quickly under UV irradiation and slowly under visible irradiation. The initial concentration of oxalate is a main factor to affect BPA photodegradation in aqueous suspension under both UV and visible lights. Show more

Keywords: bisphenol A, lepidocrocite, oxalate, photodegradation

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 777-782, 2006

Authors: JIANG, Fang | ZHENG, Shou-rong | ZHENG, Zheng | XU, Zhao-yi | WANG, Yan-jin

Article Type: Research Article

Abstract: TiO_2 nanotube precursor was synthesized by the hydrothermal reaction of TiO_2 powders with NaOH solution and the properties of the nanotube materials were tuned using different post-treatments. Transmission electron microscopic (TEM) observation revealed that the nanotube could be obtained by either a direct rinse with acid solution or rinse with distilled water followed by acid solution. The results of X-ray diffraction (XRD) and inductively coupled plasma (ICP) analysis indicated that …the nanotube material was composed of H_2 Ti_2 O_5 ·H_2 . In addition, the photocaalytic activities of the resulting catalysts were found to be strongly dependent on the post-treatment. The results of the photocatalytic reaction showed that the degradation of Acid-red 3B dye fitted pseudo-zero-order kinetics and TiO_2 nanotube prepared under direct rinse with acid solution exhibited a higher catalytic efficiency compared to other catalysts. Show more

Keywords: TiO_2 nanotube, Acid-red 3B, photocatalysis, hydrothermal reaction

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 783-787, 2006

Authors: CHENG, Jin-ping | HU, Wei-xuan | LIU, Xiao-jie | ZHENG, Min | SHI, Wei | WANG, Wen-hua

Article Type: Research Article

Abstract: Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of …malondialdehyde (MDA), superoxide dismutase (SOD), GSH-peroxidase (GSH-px) and Glutathione (GSH) in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (P<0.01). It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes (IEGs); free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food. Show more

Keywords: Wanshan mercury mine, mercury polluted food, oxidative damage, c-fos

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 788-792, 2006

Authors: Lertsirisopon, Ruttapol | Soda, Satoshi | Sei, Kazunari | Ike, Michihiko | Fujita, Masanori

Article Type: Research Article

Abstract: Biodegradability of di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-ethylhexyl phthalate (DEHP), and di-isononyl phthalate (DINP) under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters(PAEs)were analyzed by a first-order kinetic model with a lag phase and ranked as DBP>BBP>>DEHP>DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded …with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5–30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of DINP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment. Show more

Keywords: phthalic acid esters, anaerobic biodegradation, sediment, first-order kinetics

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 793-796, 2006

Authors: Imran, Hashmi | Altaf, Khan M | Kim, Jong-Guk

Article Type: Research Article

Abstract: Popular descriptive multivariate statistical method currently employed is the principal component analyses (PCA) method. PCA is used to develop linear combinations that successively maximize the total variance of a sample where there is no known group structure. This study aimed at demonstrating the performance evaluation of pilot activated sludge treatment system by inoculating a strain of Pseudomonas capable of degrading malathion which was isolated by enrichment technique. An intensive analytical program was …followed for evaluating the efficiency of biosimulator by maintaining the dissolved oxygen (DO) concentration at 4.0 mg/L. Analyses by high performance liquid chromatographic technique revealed that 90% of malathion removal was achieved within 29 h of treatment whereas COD got reduced considerably during the treatment process and mean removal efficiency was found to be 78%. The mean pH values increased gradually during the treatment process ranging from 7.36–8.54. Similarly the mean ammonia-nitrogen (NH_3 -N) values were found to be fluctuating between 19.425–28.488 mg/L, mean nitrite-nitrogen (NO_3 -N) ranging between 1.301–2.940 mg/L and mean nitrate-nitrogen (NO_3 -N) ranging between 0.0071–0.0711 mg/L. The study revealed that inoculation of bacterial culture under laboratory conditions could be used in bioremediation of environmental pollution caused by xenobiotics. The PCA analyses showed that pH, COD, organic load and total malathion concentration were highly correlated and emerged as the variables controlling the first component, whereas dissolved oxygen, NO_3 -N and NH_3 -N govemed the second component. The third component repeated the trend exhibited by the first two components. Show more

Keywords: activated sludge system, malathion, principal component analyses (PCA), raw wastewater, removal efficiency

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 797-804, 2006

Authors: LÜ, Fan | HE, Pin-jing | SHAO, Li-ming

Article Type: Research Article

Abstract: pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value (pH 5–9) with or without acetate (20 g/L). The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with …pH was not affected by the addition of acetate, following the sequence of pH 7>pH 8>pH 9>pH 6>pH 5; but the inhibition of acetate (20 g/L) was obvious by 10%–60%. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%–100%. The relationship between the factors (pH and acetate) and the response variables was evaluated by partial least square modeling (PLS). The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein. Show more

Keywords: inhibition, hydrolysis, pH, volatile fatty acids, partial least square

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 805-809, 2006

Authors: ZHANG, Ji-shi | SUN, Ke-wei | WU, Man-chang | ZHANG, Lei

Article Type: Research Article

Abstract: The influence of temperature on the performance of anaerobic reactors for treating the organic fraction of municipal solid waste (OFMSW) was studied. Batch digestion of OFMSW was carried out for 32 d at different temperature (25°C, 35°C, 45°C and 55°C) conditions for total solid concentrations (TS) 17% with the ratio of total organic carbon to nitrogen (C/N) being, 25:1 respectively, while keeping other parameters constant such as inoculum, start-up pH, reactor volume (2 L) and so …on. Temperature can influence the methanogenic bacteria activity, accordingly inhibiting the OFMSW biodegradation and stabilization efficiency. Anaerobic reactors excelled at TS reduction, total volatile solid reduction, chemical oxygen demand reduction, increasing cumulative biogas production, whose rate was at temperature (35°C and 55°C) conditions. Methane concentration in the biogas was above 65% in four reactors. In addition, the fluctuation of temperatures resulted in the biogas production variation. The data obtained indicated that temperature had a significant influence on anaerobic process. Show more

Keywords: municipal solid waste, anaerobic digestion, batch processing, temperature

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 810-815, 2006

Authors: ZHANG, Ming-kui | FANG, Li-ping

Article Type: Research Article

Abstract: The rapid growth and intensification of freshwater fishery can cause imbalances between phosphorus (P) input in feed and its output in produce. This aquaculture can result in enriching exogenous P in fishponds and, consequently, accelerates the process of eutrophication. To assess relations among input, accumulation, release of P and as a consequence degrading water quality in terms of chlorophyll-a (Chl-a) in freshwater fishponds, fourteen fishponds with feed supply, nine fishponds without feed supply, and five nonfish …ponds in Shaoxing Plain, southeast China were selected for comparing P accumulation in their waters and surface sediments. Surface sediment samples were collected from each pond to evaluate their total P, water soluble P, Olsen P, algal available P, and P fractions. Water samples were also collected from the ponds to measure concentrations of dissolved P and Chl-a. Total P in the sediments ranged from 0.88 to 1.73 g/kg in the fishponds with feed supply, that in the non-fish ponds ranged from 0.47 to 0.86 g/kg. Organic P, accounted for 23% to 60% of total P in the sediments, was an important P fraction and increased linearly with increasing organic matter. Long-term application of feeds resulted in increased P availability in the bottom sediments and degradation of water quality in the freshwater fishponds. Compared with non-fish ponds, sediments from the feed-supplied fishponds contained considerably higher Olsen P, algal available P, and water soluble P. Higher proportions of the labile P (NH_4 Cl-P) and potentially labile P (NaOH-IP) were also found in the sediments from the fishponds. High solubility of P in the sediments resulted in elevation of P and chlorophyl1-a concentration in the pond water. The dissolved P concentration in the pond water increased in the order of non-fish ponds (12 μg/L) < fishponds without feed supply (24 μg/L) < fishponds with feed supply (66 μg/L). Linear correlations between concentrations of total P, Olsen-P, algal available P, water-soluble P and P concentration in saturation extracts in the sediments and dissolved P in the pond water indicated that there was a buffering action of the sediment constituents on the dissolved P. Show more

Keywords: eutrophication, freshwater fishery, phosphorus fraction, water quality

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 816-821, 2006

Authors: LIU, Li-yan | JIANG, An-xi | REN, Nan-qi | JIANG, Gui-bin | LI, Yi-fan

Article Type: Research Article

Abstract: The use of technical HCH (1, 2, 3, 4, 5, 6-hexachlorocyclohexane), DDT (dichlorodiphenyltrichloroethane) and lindane in Heilongjiang River Basin (HRB) of China was studied. Between 1952 and 1984 the total usage in the HRB was 108900 t for technical HCH, and 4900 t for DDT, respectively, and the use of DDT due to dicofol application in the HRB was 220 t from 1984 to 2003. The usage of lindane in HRB was 109 t from 1991 to 2000. The results …show that the highest technical HCH use (41800 t) in HRB was on maize, accounting for 38.3% of the total usage on all crops, followed by the use on wheat (28000 t, 25.7%) and on soybean (26600 t, 24.4%). The highest DDT use (2300 t) was on soybean, accounting for 46.8% of the total usage on all crops, followed by the use on maize (1500 t, 31.3%) and on sorghum (600 t, 13.2%). The major use of lindane was mainly on wheat. Gridded usage inventories of these three OCPs (organochlorine pesticides), in HRB with a 1/6 ° latitude by 1/4 ° longitude resolution have been created by using different gridded cropland as surrogates. Some soil samples have also been collected in HRB. Data of usage and soil concentrations of Σ HCH in HRB match quite well to those in Shanghai region, and much higher soil concentration of Σ DDT in Shanghai region could be due to much heavier dicofol use in this region. Show more

Keywords: persistent organic pollutants (POPs), organochlorine pesticides (OCPs), DDT, HCH, lindane, inventories, Heilongjiang River Basin

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 822-826, 2006

Authors: ZENG, Yong | YANG, Zhi-feng | LIU, Jing-ling

Article Type: Research Article

Abstract: The weekly water quality monitor data of Liuhai lakes between April 2003 and November 2004 in Beijing City were used as an example to build an artificial neural networks (ANN) model and a multi-varieties regression model respectively for predicting the fresh water algae bloom. The different predicted abilities of the two methods in Liuhai lakes were compared. A principle analysis method was first used to select the input variables of the models to avoid the phenomenon …of collinearity in the data. The results showed that the input variables for the artificial neural networks were T, TP, transparency(SD), DO, chlorophyll-a (Chl-a),pH and the output variable was Chl-a. A three layer Levenberg-Marguardt feed forward learning algorithm in ANN was used to model the eutrophication process of Liuhai lakes. 20 nodes in hidden layer and 1 node of output for the ANN model had been optimized by trial and error method. A sensitivity analysis of the input variables was performed to evaluate their relative significance in determining the predicted values. The correlation coefficient between predicted value and observed value in all data and in test data were 0.717 and 0.816 respectively in the artificial neural networks. The stepwise regression method was used to simulate the linear relation between Chl-a and temperature, of which the correlation coefficient was 0.213. By comparing the results of the two models, it was found that neural network models were able to simulate non-linear behavior in the water eutrophication process of Liuhai lakes reasonably and could successfully estimate some extreme values from calibration and test data sets. Show more

Keywords: artificial neural networks, eutrophication, multi-varieties regression, forecast, Liuhai lakes, Beijing City

Citation: Journal of Environmental Sciences, vol. 18, no. 4, pp. 827-831, 2006