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Table of Content

Volume 29 Issue 6
25 November 2013
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Trend of the Climate Changes in Dry Valleys of Hengduan Mountains, China
DING Wen-Rong
2013, 29(6):  681-687. 
Abstract ( 889 )   HTML ( 170)   PDF (1138KB) ( 2121 )  
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A long period of meteorological data collected at 20 typical meteorological observation stations scattered in dry valleys of the Hengduan Mountains, including monthly air temperature, precipitation, relative humidity, sunshine hours, highest air temperature and lowest air temperature, were cited for analysis of trend of the climate changes in the region, using the  linear tendency estimation, Mann-Kendall test, precipitation concentration degree (PCD) and precipitation concentration period (PCP) methods. Results show that (1) affected by the global climate change, the mean air temperature in the dry valleys presented generally a rising trend with a rate of 0.11℃•(10a)-1 , a bit lower than the rate [0.15℃•(10a) -1]of the whole Hengduan Mountains and it was more obvious in in winter than in other seasons; (2) the mean air temperature in Yuanmou, Dongchuan and Qiaojia Valleys in the downstreams of the Jinsha River displayed a declining trend, more obvious in spring; (3) the precipitation in the dry valleys dropped slightly, by1.48mm•(10a)-1, which is mainly attributed to the reduction of precipitation in summer, which was more obvious than that in other seasons; (4) annual precipitation in most of the dry valleys weakened in PCD, but temporally advanced in PCP, though not so obvious; and (5) relative humidity and sunshine hours presented a declining trend in recent decades. The former decreased at a rate of 0.16%•(10a)-1 and the latter at a rate of 24.26h•(10a)-1.
Trajectory and Driving Forces of Change in Farmland in Nanjing During the Period From 1985 to 2010
LIU Gui-Lin, ZHANG Luo-Cheng, ZHANG Qian
2013, 29(6):  688-694. 
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With rapid economic development, urbanization of Nanajing is accelerated vigorously, thus causing tremendous change in land use in the region. Based on Landsat MSS/TM images of the region from 1985 to 2010, land use data of the past years were acquired using the maximum likelihood method and sorted into two categories, farmland and non-farmland. Based on the classification, the land was further sorted into five groups, that is, permanent farmland, permanent non-farmland, transforming into farmland, transforming into non-farmland and tentative farmland, in light of their natures of land use, showing trends of the change in land use.  Spatio-temporal dynamics of the landscape patterns of the five groups of land in change wasere analyzed by means of using the percentage of Landscape iIndex (PLAND), and the Interspersion and juxtaposition Iindex (IJI) to show spatio-temporal trajectories of the farmland in expansion and desertion. Results show that (1) the farmland decreased in area by 40.42% from 1985 to 2010; (2) permanent farmland in Azimuth 3 was the highest in area, accounting for 56.89% of the total; transformation into non-farmland occurred  mainly in Azimuths 1, 6 and 8, which reveals the main direction of urbanization; (3) permanent farmland was mainly distributed in Liuuhe District, making up 895.92km2 and transformation into non-farmland occurred mainly in Jiangning District; (4) permanent non-farmland was mainly located in the urban region while permanent farmland was in the opposite direction; (5) permanent farmland was still in dominancy, land under transformation into non-farmland was highly fragmented and tentative farmland was not stable in area and susceptible to desertion  and even degradation; and (6) shifting of the population and industrial centers, economic development, policies and urban expansion were the key factors significantly affecting change in farmland.
Phosphorus Flow Analysis of Rural Circular Economy System in Japan: A Case Study of Nakasatu Village in Hokkaido
SHI Feng
2013, 29(6):  695-699. 
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Based on the introduction to a the typical Japanese rural circular economy model, phosphorus flow in the a rural circular economy system is analyzed using the material flow analysis method. Results show that the use of large amounts of compost and direct application of animal manure to the field reduces the effect of wastes from livestock and rural domestic life on water environment, but it did not have any critical effect on control of phosphorus release from crop fields. On such a basis, it is suggested that in constructing new countryside, it be wise to consider building a circular economy model integrating rural domestic life, cropping and animal rearing and expanding recycling of the wastes from rural domestic life, so as to reduce pollution to the off-system environment.
Investigation and Analysis of the Eenvironment of Ttypical Chinese Mmedicinal Herbs Production Areas in Jinhua, Zhejiang Province
YIN Han-Qin, JIAN Zhong-Hua, XU Ming-Xing, WEI Ying-Chun
2013, 29(6):  700-704. 
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Samples were collected of soils from the plow layers of the major Chinese medicinal herbs production areas in Jinhua and of the Chinese medicinal herbs produced therein for analysis of heavy metal contents and causes of their overproof rates from the environmental geochemical aspect. Results show that the Cd overproof rate in Rhizoma Atractylodis, Macrocephalae,Radix Scrophulariae and Bulbus Fritillariae Thunbergii is 64.3%, 40.0% and 47.2%, respectively, and the Cu overproof rate in Rhizoma Atractylodis, Macrocephalae,Radix Scrophulariae and Bulbus Fritillariae Thunbergii is 35.7% ,10.0% and 5.9%, respectively. It was found through studies on the characteristics of Chinese medicinal herbs selectively absorbing certain heavy metal elements, soil environment of the herb growing areas, topographic and climatic conditions that the warm humid climate, steep terrain, strong eluviation in the process of pedogenesis through weathering of rocks, decreasing pH from soil parent material, eluvial horizon to plough layer and soil acidification are the major causes leading to overproof Cu and Cd in the Chinese medicinal herbs.
Effect of Riverside Shelter Forest Communities Protecting Embankment From Erosion in Huai’an Section of the Beijing-Hangzhou Grand Canal
LI Dong-Lin, JI Yong-Hua, DAI Xiao-Lin, LIU Jin-Song, DING Jing-Jing
2013, 29(6):  705-710. 
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Effect of riverside shelter forest communities protecting embankment from erosion in the Huai’an section of the Beijing-Hangzhou Grand Canal was studied. It was found that the shelter forests significantly improved physical properties of the soil by increasing total porosity and capillary porosity, and decreasing soil bulk density. The effect varied with the composition of the vegetation community. Poa annua communities and Ligustrum lucidum communities significantly increased the content of soil organic matter, soil aeration and water holding capacity. Of the embankment, sections covered with vegetation were significantly higher in erosion resistance than those of bare land. Relatively speaking, the soil under Poa annua community was the highest in soil erosion resistance (0.892), and followed by those under Ligustrum lucidum (0.835), Pyrus bretschneideri (0.791), Prunus persica (0.530), and Metasequoia glyptostroboides (0.397), and bare land (0.341). Positive relationships were observed of soil erosion resistance with root biomass, average root number, and soil organic matter content with correlation coefficient being 0.9611, 0.9659 and 0.7742, respectively.
Effect of Intercropping on Soil Microflora in Rhizosphere Soil of Potato Under Continuous Cropping
WANG Chun-Ming, MA Kun, DAI Xiao-Hua, LIANG Yi
2013, 29(6):  711-716. 
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To explore feasibilities and mechanisms of different cropping systems alleviating obstacles to mono-cropping of ppotato, a field experiment was carried out, consisting a plot of mono-cropping of potato as CK, a plot of intercropping of potato and corn, a plot of intercropping of potato and broad bean, and a plot of intercropping of potato and buckwheat. Changes in soil nutrient contents and microflora in the rhizosphere of monocropping potato were investigated. Results show that all the three intercropping plots were significantly lower than CK in total nitrogen, total phosphorus, readily available phosphorus and readily available potassium in rhizospheric soil and in soil pH . The decrease in readily available P was particularly significant, reaching at least 45%. Intercropping altered microbial community structure as indicated by significant decrease in the total counts of fungi in the rhizospheric soil. Besides, intercropping also significantly affected carbon source utilization capacity of the rhizospheric microbial community. Especially the intercropping of potato with broad bean and with corn was 13.39% and 4.30% higher than CK in AWCD (average well color development) after 120 hours of incubation of rhizospheric microbes.On the whole, the microbial community in the rhizospheric soil of potato plants in all the treatments was higher in carbohydrate utilization rate, but lower in aromatic compound utilization rate. Intercropping significantly enhanced carbon metabolism of the soil microbial community in the rhizosphere of potato, thus helping sustain stable production of potato. Therefore, intercropping may be used as an approach to improving rhizospheric micro-eco-environment of monocropping potato and alleviating obstacles to potato monocropping.
Evaluation of Agricultural Multi-Functional Value of the Living Ancient Torreya grandis Community in Kuai Ji Mountain
XU Yuan-Tao, MIN Qing-Wen, BAI Yan-Ying, YUAN Zheng, WANG Bin, HE Lu, CHEN Jin-Yu
2013, 29(6):  717-722. 
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Torreya grandis is an ancient species of arbor tree native to China and a rare economic species in the world as well. Currently, the ancient T. grandis community in the Kuai Ji Mountain has been listed as candidate site of the global agro-cultural heritage and important agro-cultural heritage of China. Based on the features of the ancient T. grandis community, an overall evaluation of the agricultural multi-functions of the forest was performed from the following five aspects, i.e. economical function, biodiversity conservation function, agricultural landscape conservation function, agro-cultural bequeathment function and ecological environmental protection function, using the agricultural multifunction multi-dimensional evaluation model. Results show that its agro-cultural bequeathment function index is the highest, equaling to 1, its ecological environmental protection index 0.85, its agricultural landscape conservation function index 0.43, and its economic function value and biodiversity protection function index was relatively low, being 0.25 and 0.29, respectively, indicating that the leading function of the ancient T. grandis community in the Kuai Ji Mountain is the agro-cultural bequeathment, which is followed by ecological environment protection function and agricultural landscape conservation functions.
Fate of Complex Pollutants of Lead and Benzo[a]pyrene in Soil-Plant System
WANG Shuai, WANG Hong-Qi, WANG Rui-Bin, ZHANG Xin
2013, 29(6):  723-730. 
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An indoor pot experiment was conducted to study fate of complex pollutants of Lead (Pb) and Benzo[a] pyrene (B[a]p), low and moderate in concentration, in the soil-plant system and interaction between the two pollutants. The experiment was designed to 4 factors and 6 levels with Pb concentration varying in the range of of 0-1 120 mg·kg-1 and B[a]p concentrations in the range of 0-6.4 mg·kg-1 in the soil. Results show that in bulk soil, Pb, regardless of forms, was not affected by the coexisting B[a]p and the natural degradation of B[a]p was also not either by the coexisting Pb. In the rhizosphere soil of ryegrass, the contents of exchangeable and carbonate bound Pb and Fe-Mn bound Pb were obviously lower than in the non-rhizosphere soils, while the contents of organic and sulfide bound Pb significantly higher, which may be attributed to exudation and Pb absorption of the ryegrass roots. Pb concentrations in shoots and roots of corn and ryegrass were found significantly and positively related to the total content of Pb in the soil, but not to content of the coexisting B[a]p. The degradation rates of B[a]p were increased significantly in the corn and ryegrass rhizopheres compared to that in non-rhizosphere soil. The effect of ryegrass is much higher than that of corn. The coexisting Pb in the rhizosphere soils had some inhibiting effect on B[a]p degradation, which may be related to the effect of the rhizosphere environment activating Pb and hence increasing microbial availability of Pb in the rhizosphere soil. Pb also had some effect on absorption of B[a]p by roots. In short, it can be concluded that the coexistence of Pb and B[a]p does not have any effects on the fate of Pb in both rhizosphere and non-rhizosphere environment and Pb has no effect either on the fate of B[a]p in non-rhizosphere environment. However, in rhizosphere environment, Pb does affects the degradation of B[a]p as well as the absorption of B[a]p by roots.
Effect of Substrate Amelioration on Growth of Robinia Pseudoacacia in a Typical Deserted Zinc Smelting Site
LIN Wen-Jie, XIAO Tang-Fu
2013, 29(6):  731-737. 
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Revegetation can be a suitable option to control pollution in deserted mining sites. A pot experiment and a field experiment using Robinia pseudoacacia were carried out in a deserted zinc smelting site, typical of Hezhang County, Guizhou Province, China to explore effects of various soil amelioration approaches on soil physical-chemical properties, contents of heavy metals, growth of R. pseudoacacia and limiting factors in revegetation. Results show that the limiting factors in revegetation of slag wasteland of slag were mainly salt-alkali stress, low contents of total N, available N and total K, high concentrations of Pb, Zn and Cd and low water retention capacity. Although elevated Pb, Zn and Cd concentrations were present in the slag wasteland, their exchangeable fractions were low. Amendment of the new slag wasteland of new slags with the soil from the site may lower pH and EC, reduce salt-alkali stress and increase water retention capacity of the land, thus significantly improving the survival and growth rate of R. pseudoacacia therein. Therefore, the amendment was an effective method to ameliorate the substrate or the wasteland for revegetation. Years of leaching significantly reduced salt-alkali stress to the trees, and increased available soil water content of the wastelands. Application of hydrogel or soil from the mining site can effectively help the survive and establish of R. pseudoacacia survive and establish in old slag wastelands.
Removal of Pollutants From Soil Infiltration Systems
LI Yi, SHEN Jian, LIN Yan, WANG Xin-Ze
2013, 29(6):  738-742. 
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Hydraulic load, organic load and the C/N ratio are main factors affecting nutritive salt removal efficiency of wastewater soil infiltration systems. In a laboratory with controlled temperature, effects of hydraulic load, organic load and environmental conditions on pollutants removal efficiency of soil infiltration systems were analyzed. Results show that when hydraulic load was lower than 0.15 m3•m-2•d-1, removal efficiencies of CODCr, TN and P in simulated domestic sewage reached over 84%, 37% and 93%, respectively, meanwhile the number of Nitrosomonas was up to 4.50×106 per gram dry soil. The perched water in the upper layer of the installation did not affect much the removal efficiencies of CODCr, and phosphates. However, as a result of lowered dissolved oxygen in the system, nitrification of ammonia nitrogen was inhibited and the removal efficiency of ammonia nitrogen and TN lowered. Under the condition of enough DO, higher C/N ratio (5:1) was conducive to TN removal efficiency in the system.
Toxic Effects of Repeated Superimposed B[a]P Pollution of Soil on SOD, POD and MDA in Coelomocytes of Eisenia foetida
MA Jing-Jing, ZHENG Bin, ZHANG Wei, GE Gao-Fei, GAO Hong-Jian
2013, 29(6):  743-748. 
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As a persistent organic pollutant (POP), benzo(a)pyrene (B[a]P) is gradually accumulating in the soil, posing a serious threat to the soil environment quality. The routine approach to environmental risk assessment of B[a]P is only based on one-time pollution, i.e. mixing the soil with B[a]P only once, which deviates from the step-by-step procedure of B[a]P entering the soil. In this paper, a toxic bioassay was conducted to investigate toxic effects of B[a]P on superoxide dismutase (SOD) and peroxidase (POD) activities and malondialdehyde (MDA) levels in coelomocytes of earthworm (Eisenia fetida), using the multiple-time superimposed and one-time pollution methods. Results show that with the exposure to B[a]P going on, SOD and POD activities and MDA content in coelomocytes of earthworm dropped rapidly in the first 14 days (1-14 d), and then declined slowly in the 42 days to follow (14-56 d) under both the multiple-time superimposed and one-time pollution methods. In the first 14 days, the SOD activity and MDA content in earthworms found in the 0-20 cm soil layer under superimposed pollution was 20.97% and 15.96% lower, respectively, while POD activity was 20.44% higher than that under one-time pollution. However, the SOD and POD activities, as well as the MDA content in earthworms found in the >20-40 cm soil layer under superimposed pollution was 52.89%, 18.00% and 70.60% lower than that under one-time pollution, respectively. All the above findings suggest that toxicity of multiple-time superimposed B[a]P pollution to earthworms was lower than that of one-time pollution. The study provides crucial data for evaluating ecological toxicity of cumulative B[a]P pollution in the soil.
Physiological Effect of Exposure to Nonylphenol Polyethylene Glycol Ether on Eisenla foetida
BU Yuan-Qing, SHAN Zheng-Jun, ZHI Yong, ZHANG Kai, JIANG Jin-Lin
2013, 29(6):  749-754. 
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An acute contact test and an artificial soil test was conducted to study lethal and oxidizing effects of nonylphenol polyethylene glycol ether (NPEO) on earthworm (Eisenia fetida). Results show that the 48-h median lethal dose of NPEO was 0.58 mg•L-1. The artificial soil test shows that NPEO induced the activity of CAT and GST and increased the content of GSH and MDA. After 28 hours of exposionure, CAT and GST activities and GSH content was found to be positively related to the concentration of NPEO(P<0.05). However, increased NPEO concentration slightly suppressed the activities of SOD and Cu-Zn SOD. The above findings indicate that NEPO of sub-lethal dose may generate physiological stress and certain extent of oxidizing damage to the earthworms.
Preparation and Adsorptive Properties of Carbonized Rice Straw Based Phosphate Sorbent
YANG Yang, ZHANG Yi-Min, LIAN Jian-Jun, DUAN Jin-Cheng, ZHOU Chuang, LIN Chao
2013, 29(6):  755-761. 
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Through carbonization, pre-oxidization with KMnO4 and modification with FeSO4, rice straw was prepared into low-cost modified carbonized rice straw (MCRS). Physical and chemical properties of the carbonized rice straw and MCRS were analyzed with Zeta potential analyzer, scanning electron microscope (SEM), alpha ray spectrometer (ARS), specific surface area analyzer (BET), Fourier transform infrared spectrum analyzer (FTIR) and X-ray diffraction analyzer (XRD). Meanwhile static adsorption tests were carried out to explore effects of dosage of the adsorbent, pH and temperature on phosphate adsorption efficiency of the adsorbent. It was found that phosphate adsorption on MCRS was an endothermic process, and its adsorption isotherm fitted well with the Langmuir equation. In the solution, 7 in pH, 4g•L-1 of MCRS was added, the phosphate removal rate could reach as high as 96%, and at 30 ℃,it could adsorbed as much as 5.49mg•g -1 phosphorus, according to the Langmuir equation.
Potential Ecological Risk Assessment of Heavy Metals in River Sediments of Drinking Water Sources of Huangpu River
ZHENG Ling-Fang
2013, 29(6):  762-767. 
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The upper streams of the Huangpu River is an important drinking water source area for Shanghai. To better characterize heavy metal pollution of the region, samples of sediments were collected from 15 sampling points distributed in the main stream and major tributaries of the Huangpu River for analysis of Cu, Pb, Cd, Hg and Zn contents and for ecological risk assessment. It was found that all the five heavy metals, with Cd and Hg in particular, in the 15 samples exceeded the medians of their respective environment background values by a varying extent, and only Cu and Cd exceeded their respective highest background values. Ecological risk assessment using the potential ecological risk index method and the pollution load index method shows that the ecological risks of the heavy metals in the study area could be sorted as “no pollution” or “moderate pollution”, and Sampling Point #1, #5, #9, #11, #12 and #13 were comparatively high in ecological risk. Cd and Hg are the two dominant ecological risk contributors in the study area. It is noteworthy that some of the tributaries, like Dazhenggang and Yuanxiejing, were, on the whole, higher than the main stream in ecological risk. Generally speaking, heavy metal pollution in river sediments of the upper streams of the Huangpu River is still lower than the “medium level”.  
Screening of Strains of Cellulase-producing Bacteria in Compost of Sewage Sludge and Straw and Optimization of Cellulase-Producing Conditions
SHE Ting-Ting, GE Xiao, LI Mai-Jun, ZHANG Sheng-Hua, CHU Yan-Chun, GUO Hai-Ning, WANG Xiao-Zhi, FENG Ke
2013, 29(6):  768-772. 
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Samples collected from compost of sludge and straw were incubated for enrichment culture, and then strains of  bacteria capable of decomposing cellulose were screened out with the Congo red staining plate method. Enzyme activities of the stains of bacteria were measured and one strain, relatively higher in cellulose-producing activity, was isolated as C1. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolated strain of bacteria, C1, was preliminarily identified as Devosia sp. Single factor experiments were adopted to optimize the fermentation conditions for C1. Results show that for C1, 60 hours of incubation at 30℃ with the culture medium being in the range of 7.2-7.5 in initial pH in the shaker rotating at a rate of 130 r•min-1 was the optimal cellulase-producing condition. Under such conditions, the activities of filter paper enzyme(FPase)and carboxymethyl cellulase(CMCase)produced by Strain C1 reached 23.10 U•mL-1 and 54.97 U•mL-1 respectively.
Effects of Cleaning Dredged Material on Growth of Two Species of Marine Microalgae as Affected by its Particle Size and Concentration
DONG Peng, XU Ren, LIU Cai-Cai, LIU Han-Qi, QIN Yu-Tao, DENG Bang-Ping, LIU Shou-Hai
2013, 29(6):  773-778. 
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A simulation test was carried out in laboratory to study effects of cleaning dredged material on growth of two species of marine microalgae (Chlorella sp. and Nitzschia closterium) as affected by its particle size and concentration. Results show that after 8 days of incubation, the effect of the materials on growth of the two species of marine microalgae was very significant regardless of their concentration (P<0.01). In the case that the suspended cleaning dredged materials were in the same range of particle size, but varied in concentration in the range of 1- 7 g•L-1, the effect of inhibiting growth of the microalgae intensified with the rising concentration. With the suspended cleaning dredged materials declining in particle size, the two species of marine microalgae showed a downward trend in cell density. The effect was the least when the material was in the range of >88-125 μm in particle size, and the greatest when the material in the range of 0-16μm in particle size. The suspended cleaning dredged materials inhibited the growth rates of the two species of marine microalgae significantly, delaying the appearance of the maximum specific growth rate. Two species of marine microalgae were different in sensitivity to the suspended cleaning dredged materials. Chlorella sp. was more sensitive, which may be attributed to their difference in cell structure, physiological property and ecological habit.
Factors Affecting Enthusiasm of Farmers in Attending Training for Alternative to Dicofol
ZHOU Ke, MA Tao, JIA Xiang-Ping
2013, 29(6):  779-783. 
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The technology of integrated pest management (IPM) is oriented to integrate biological, agronomic and physical means in pest control, so as to rationalize the use of chemical pesticides, lower agricultural production cost, protect farmers’ health and eco-environment. With the progress of industrialization and urbanization, China has seen her agricultural labor force aging and feminized. How China can sustain her agricultural production to meet the growing demand for food is a challenge to the country but also to the world. By making use of the data available from the joint project “demonstration for use of IPM technology as alternative and control of the production of DDT containing dicofol in China” initiated by UNDP and the Ministry of Environment Protection of China, systems analysis was conducted of main factors affecting enthusiasm of farmers to attend IPM training. Results show that scale of the farming is the major factor, while gender and age is not. The more trainings the farmers attend, the more likely they are to adopt IPM technique. Farmers training courses should attract more aged and female farmers into the training for alternative to dicofol and adoption of IPM technique.
Methods for Monitoring of Amphibians and Monitoring Programmes in Foreign Countries
WU Jun, GAO Ti, XU Hai-Gen, CUI Peng, CHEN Lian, DING Hui
2013, 29(6):  784-788. 
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Amphibians, an integral part of biodiversity, are very sensitive to any changes in environment, so that they can be used as indicator species for environmental monitoring. It is essential to monitor amphibians because they are threatened environmentally worldwide recently. A detailed introduction is presented here to indicators, timing and frequency of amphibian monitoring, and main methods as well, including visual encounter surveys, transect sampling, surveys at breading sites, calling surveys, straight-line drift fences and pitfall traps, artificial cover and mark-pecapture, of which applicability and limitations were analyzed separately. Two foreign programmes of amphibian monitoring, i.e.  Amphibian Research and Monitoring Initiative of US and National Amphibian and Reptile Recording Scheme of UK have been introduced.
Identification of Outliers of Heavy Metals in Soil of a Contaminated Site and Separation of Point Source Effects
WU Yun-Jin, HE Yue, DENG Shao-Po, XU Jian, ZHANG Sheng-Tian, LONG Tao, LIN Yu-Suo
2013, 29(6):  789-795. 
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Spatial distribution of outliers and magnitude of point source effects of heavy metals in soil caused by point source contamination will affect accuracy of the environment risk assessment of and making of soil remediation schemes, and further environmental management of the contaminated site. A typical heavy metal contaminated site was selected for the study and Cd concentration in the topsoil was set as object. A robust variogram model was introduced to screen out a suitable variogram model. Outliers of Cd concentration in the topsoil were identified and processed and point source effects were effectively isolated with the aid of the winsorization method. Results show that the spatial variation of Cd concentration in the topsoil is great with obvious outliers. The Cressie-Hawkins robust variogram is more suitable for estimation of semi-variogram of Cd content in the topsoil. The use of the robust variogram model in couple with the winsorization method can effectively identify outliers and separate point source effects. The outliers are mainly distributed at the locations with significant human activity. As the quasi-point process often leads to sharp variation, the isolated point source effects can explain most of the Cd concentration in the topsoil of the sites of outliers.
Characteristics and Estimation of Rural Sewage Pollutants Abatement inby Surface Soil of in Typica Rural Regions Typical ofof the Taihu Lake Basin
WAN Yin-Jing, WANG Wen-Lin, ZHOU Feng, LIU Bo, TANG Xiao-Yan, LIANG Bin
2013, 29(6):  796-803. 
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Samples of surface soils near the outlets of farmer household septic tanks and samples of the effluents from the tanks were collected in a plain river network region typical of the Taihu Lake Basin for use in an in-laboratory experiment with simulated rainfall (for summer, 30 mm per event and for winter 5 mm per event, typical of the region) controlled temperature (27℃ for summer and 5℃ for winter,typical of the region) and simulated pollutant load [TN: (2.35±0.06) g·m-2·d-1, NH4+-N: (2.08±0.04) g·m-2·d-1, TP: (0.21±0.01)  g·m-2·d-1, COD: (11.14±0.59)  g·m-2·d-1] to estimate pollutants abatement rate in the polluted surface soils and to explore rules of the abatement as affected by seasons (summer and winter) and synoptic process (before the rain, during the rain, after the rain). Results show that TN abatement rates, no matter whether before the rain, in the rain, or after the rain, all showed a tendency of summer < winter (P<0.01), and on the contrary, NH4+-N abatement rates all showed a reverse trend of summer > winter (P<0.01). TP abatement rates showed a tendency of summer > winter (P<0.001) before the rain and after the rain, but COD abatement rates did not differ much between summer and winter. TP and COD abatement rates in the rain both showed a tendency of summer < winter (P<0.01 or P<0.001). As to difference between weather processes, TN abatement rates in summer showed a tendency of after the rain > before the rain> in the rainy days (P<0.01), TP and COD abatement rates in summer showed a tendency of after the rain≈after the rain> in the rainy days (P>0.05, P<0.01), whereas, NH4+-N abatement rates in summer did not differ much between  synoptic processes and TN, NH4+-N, TP and COD abatement rates in winter did not either (P>0.05). So, the TN abatement rate before the rain, in the rainy days, after the rain in summer and in winter was 38.5%, -25.0%, 46.0% and 50.4%, respectively. The NH4+-N abatement rate in summer and in winter averaged 91.5% and 85.5%, respectively. The TP abatement rate in the rainy days in summer, in the rest of summer and in winter averaged 63.3%, 93.1% and 82.7%, respectively. The COD abatement rate in the rainy days in summer and in the rest of the year was 8.2% and 66.2%, respectively, on average.
Model for Identifying Environmental Factors Significantly Associated With Cyanobacterial Bloom Intensity
HUANG Wei, SHANG Zhao-Tang
2013, 29(6):  804-810. 
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To identify environmental factors significantly associated with cyanobacterial bloom intensity and to overcome the problems, such as unreasonable selection of dependent variables, low spatio-temporal precision in the present researches, a multi-factor linear regression model was developed for the study on cyanobacterial bloom in the Taihu Lake, using cyanobacterial bloom intensity scale as dependent variable, and monitoring indices of water quality, hydrology, and weather as independent variables. Based on the data of covering areas and aggregation intensities of the blooms, a 7-level scale was designed to indicate bloom intensity, thus making the dependent variable macroscopic and avoiding the problem of lacking microscopicity in using only analogous indices, like chlorophyll a concentration, to represent bloom intensity. The temporal precision of this data set reached as high as twice a day for sampling, and the spatial precision as high as the spatial scale of a certain patch of water in a bay of the Taihu Lake.  Thus, the dependent variable becomes somewhat macroscopic, while the values of independent variables correspond strictly to the value of the dependent variable on the basis of a high spatial-temporal precision. This model was applied to the study on cyanobacterial bloom in Lake Taihu Lake of China. Analysis using the model reveals that the intensity grade of cyanobacterial bloom in the Dagongshan water area of Taihu Lake had was significantly and positively related to air temperature and nitrate concentration in water and negatively to wind speed, humidity, and electrical conductivity. The above conclusions conform to the mainstream conclusion in this research field, which manifests the effectiveness of this identification model.
Effects of Diurnal Variation of Hydrilla verticillata Photosynthesis on Nitrogen and Some Other Major Environmental Factors in Water
MAO Li-Na, WANG Guo-Xiang, ZHANG Li-Min, DONG Bin, ZHOU Feng, LI Zhen-Guo
2013, 29(6):  811-815. 
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A simulated plant-water-sediment micro-ecosystem was established in an experiment using an alien species of submerged plant, Hydrilla verticillata to study the effects of the diurnal changes in physiological activities of H. verticillata on migration and transformation of nitrogen and some other environmental factors in water. Results show that the presence of H. verticillata significantly increased DO concentration, pH,  and Eh, but lowered TDS. The diurnal variations of water pH, DO and Eh all displayed a single-peak curve. The peaks appeared all around 15:00. In addition, the concentrations of total nitrogen (TN) and NH4+-N remained nearly constant but relatively lower than that of the control during the whole day, . Tthe mean concentration of NO3--N was relatively higher between 15:00 to 18:00, and the mean concentration of NO2--N relatively lower between 24:00-2:00 next day as compared to the control.