Table of Content

Volume 27 Issue 3
25 May 2011
Advances in the Study of Species Richness Pattern
CHEN Sheng-Dong, XU Hai-Gen, CAO Ming-Chang, ZHANG Dang-Quan, WU Wei-Wei
2011, 27(3):  1-9. 
Abstract ( 1119 )   PDF (1092KB) ( 2379 )  
Related Articles | Metrics
Four most attracting hypotheses, i.e. species-energy hypothesis, historical hypothesis, mid-domain effect hypothesis, and Rapoport’s rule, are elaborated. It is believed that they do explain the species richness pattern to a certain extent, however further studies need to be done to improve their university for different areas. Brsodes, common methodology and techniques used in the study on species richness patterns and factors influencing distribution of species richness are summarized and at the end prospects for the study on species richness patterns in China are presented, in the hope that they may serve as references for decision-makers in plotting regional conservation strategies for bio-species resources.
Comment and Implication of Agricultural Non-Point Source Pollution Control Practices in Scotland
WANG Xiu-Ying, WANG Xiao-Yan
2011, 27(3):  10-14. 
Abstract ( 1281 )   PDF (782KB) ( 1809 )  
Related Articles | Metrics
Agriculture is an important non-point source pollution, and a major contributor to water pollution in Scotland. In order to protect its water environment, Scotland has carried out a series of management practices, including formulation of regulations, implementation of economic policies like financial subsidies, encouragement of farmers to use scientific production methods, and adoption of technical measures, like building up wetlands and buffer strips, to reduce the impacts of agricultural non-point sources pollution. As a result, water quality in rivers has greatly been improved. The management practices Scotland has in controlling agricultural non-point source pollution were discussed, and the experience that China should take as reference were been pointed out. China may improve its management on controlling of agricultural non-point source pollution and protecting of its water environment by means of legislation, economic policies and technical measures.
Early Warning Model for Heavy Metal Contamination of Agricultural Soil in Southeast Zunyi
LUO Yan, TAN Hong, HE Jin-Lin, CHEN Kai, WEN Xi-Mei
2011, 27(3):  15-19. 
Abstract ( 1327 )   PDF (627KB) ( 1658 )  
Related Articles | Metrics
Based on analysis of the soil samples collected in Southeast Zunyi from 2003 to 2008, an early warning model and a deterioration speed model for heavy metal contamination of agricultural soil is worked out with the modified analytic hierarchy process and time series technique. The second exponential smoothing method is used to forecast index of soil pollution and speed of soil deterioration. Results show that in 37 years beginning from 2008, heavy metal contents in the soil will be to the grade of slight contamination in the region if no any protective measures taken on purpose. Verification reveals that the predicted values tally well with the measured, with an average relative error being <6%. The models are fit for agricultural areas where no serious accidents of heavy metal pollution have ever occurred and the heavy metal contents in the soil are relatively stable.
PBDEs Pollution of Soil in a E-waste Disposal Site and Its Surrounding Area
CHEN Tao, ZHOU Chun, MOU Yi-Jun, YU Bin-Bin
2011, 27(3):  20-24. 
Abstract ( 923 )   PDF (624KB) ( 1642 )  
Related Articles | Metrics
Concentrations of 8 kinds of PBDE congeners (BDE-28、BDE-47、BDE-99、BDE-100、BDE-153、BDE-154、BDE-183、BDE-209) in soils of a typical e-waste disposal site and its surrounding area in Taizhou, Zhejiang were determined with the accelerated solvent extraction (ASE) – gel permeation chromatography technology (GPC) – GC – MS method, to study concentration level, composition characteristics and vertical distribution of the pollutants in the area. Results show that BDE-209 was the major pollutant, accounting for 90% of the content of the total 8 PBDEs in the soil. The total concentration of the pollutants in the soil was higher in the site per se that in its surrounding area, being 0.625 and 0.209 mg•kg-1, respectively. PBDE concentration decreased with the distance from the center of the disposal site.
Risk Assessment of Livestock Manure in Meizhou Area of Guangdong
GONG Jun-Yong, PENG Xiao-Zhen, LIAO Xin-Di
2011, 27(3):  25-28. 
Abstract ( 935 )   PDF (521KB) ( 1357 )  
Related Articles | Metrics
The total volume of manures of all species of livestock in Meizhou was estimated using the excretion coefficient method, and the maximum animal manure loading capacity of the field was calculated, for environmental risk assessment of the industry based on pre-warning values of animal manure loading capacity of farm fields. Results show that the industry in Meizhou turned out 324.60×104 t of excrement and 180.02×104 t of urine, which included 19.36×104 t of BOD5,19.91×104 t of COD, and 2.423×104 t of NH3-N in 2008. The average livestock manure loading capacity of the field reached 23.07 t • hm-2 • a-1. The  averaged livestock manure loading early-warning value was 0.51, which could be sorted into Grade II of the overall early-warning, corresponding to “slight environmental pollution”. However, it varied from area to area. Fengshun County was the highest in early-warning value. Pingyuan County was much lower, thus giving the county much room for development of its livestock production.
Effects of Different Patterns of Contour Grass Hedgerow on Soil Erosion Control
ZHANG Pei, YAN Li-Jiao, FAN Ji, JIANG Peng, WU Yue-Yang, CAI Liang-Liang, XU Huan, WANG Xi-Jin, WU Shao-Fu
2011, 27(3):  29-34. 
Abstract ( 918 )   PDF (792KB) ( 1347 )  
Related Articles | Metrics
A run-off plot method combined with the rare earth elements tracing technique was used to study effects of contour grass hedgerows on control of soil erosion and surface run-off and spatial distribution of soil erosion on slope land in red soil hill regions of South China. Five different patterns of contour grass were planted for the experiment. It was found that soil losses from the run-off plots were obviously affected by rainfall. In run-off plots with contour grass hedgerows established, regardless of pattern, mean soil loss and surface run-off was significantly lower than in CK (bare land)(P<0.05). Among the five patterns of grass hedgerows, the one of double-row Ophiopogon japonicas was the most effective in controlling soil erosion and surface run-off. So the plot was the lowest in mean soil erosion and surface run-off, being 4 047 g and 1 554 L, respectively, while CK was the highest, being 19 793 g and 2 403 L, respectively. It was also found that through quadratic linear fitting using a model that differences existed between treatments in marginal value of soil loss as a result of variation of surface runoff. The middle and down slopes were the major source of sediments, contributing nearly 85% to the total soil loss. Although the grass hedgerows changed the soil re-distribution through sedimentation within the slope, they did not have any obvious effect on spatial distribution patterns of soil erosion on the slope.
Status Quo and Trends of biological Invasion Into China
DING Hui, XU Hai-Gen, QIANG Sheng, MENG Ling, HAN Zheng-Min, MIAO Jin-Lai, HU Bai-Shi, SUN Hong-Ying, HUANG Cheng, LEI Jun-Cheng, LE Zhi-Fang
2011, 27(3):  35-41. 
Abstract ( 1678 )   PDF (1166KB) ( 2326 )  
Related Articles | Metrics
Combining literature review, field survey and expert consultation, investigations were carried out of invasive alien species (IAS) in forest, wetland, grassland, desert, inland water and ocean (sea) ecosystems of China. A total of 488 IAS were identified with detailed information collected including name, taxonomy, distribution, origin, location and time first detected or introduced, pathway, hazard, nutrient circumstance, and habits. Of the 488 IAS,265 were plants, 171 animals, 26 fungi, 12 vira, 11 procaryotes and 3 protists. Analysis of the invasion years of the 392 IAS that have specific records reveals that only 31 IAS came in before 1850 and the number of IAS has been increasing steadily since 1850, especially since 1950. During the 60 years after 1950, 209 IAS appeared. Their debuts occurred mainly in the coastal regions and border provinces, like Yunnan Province and Xinjiang Uyghur Autonomous Region, but the stage tends to be moving northward. The percentage of intentional introduction almost equaled to that of unintentional introduction, but the latter has become the primary in recent years. America, Europe and other parts of Asia are the main origins of IAS of China. The number of IAS presents a decreasing trend from coastal towards inland.
Effects of Transgenic Bt Maize on Populations and Diversity of Soil Bacteria
LIU Ling, YANG Dian-Lin, WANG Sheng-Rong, ZHAO Jian-Ning, LI Gang, NA Bu-Qi, NA Ri-Su
2011, 27(3):  42-47. 
Abstract ( 842 )   PDF (1031KB) ( 1484 )  
Related Articles | Metrics
In this study, the three-compartment rhizobox method was used to collect soil samples from three different root zones of a maize plant, i.e. growth room (S I), rhizosphere (S II) and non-rhizosphere (S III) and the traditional plate count method and DGGE were applied to investigate changes in population and diversity of soil bacteria at D40, D50 and D60 after sowing of transgenic Bt maize and its parental maize. Results show that cultivation of transgenic Bt maize significantly reduced the population of soil cultivable bacteria in Zone S I at D50 and D60, but increased the population in Zone S II at D40 and D50, and showed no significant impact in the other zone. DGGE fingerprints indicated no significant difference between soil samples taken at different dates in DGGE bands, diversity index and homogeneous degree index of the bacteria (P>0.05).
Assessment of Impact of Hunan Disturbance on Landscape Evolution of the Core Area of the Yancheng Nature Reserve
SUN Xian-Bin, LIU Hong-Yu
2011, 27(3):  48-52. 
Abstract ( 846 )   PDF (869KB) ( 1308 )  
Related Articles | Metrics
Based on the data of the three phases of wetland landscape evolution, the CA-Markov model was used to simulate temporal and spatial evolution processes of wetland landscape of the core area of Yancheng Nature Reserve as affected by different conditions, with a view to exploring impacts of natural and anthropogenic factors on the landscape of the area and trend of its evolution. Results show that human management altered the evolution processes of the wetland landscape in the northern section of the core area. During the period from 1987 to 2007, the reed marsh belt and the Spartina alterniflora marsh belt expanded rapidly in width, with their proportion in area increasing from 5.62% to 60.20%, and from 1.91%to 7.78%, respectively, thus cutting the proportion of seepweed marsh from 67.50 to 7.21%. its wetland landscape gradually changed in composition from four distinct belts (reed marsh – seepweed marsh – Spartina alterniflora marsh - mudflat) to three (reed marsh – Spartina alterniflora marsh - mudflat) and by 2013, the belt of seepweed marsh will have disappeared in the northern section. In the southeastern section of the core area, natural succession dominated the evolution of the landscape in structure. Dotted patches of Spartina alterniflora marsh in 1987 expanded and merged into a belt in 2007, with its proportion in area increasing from 2.75% to 36.54%. The belt of reed marsh increased steadily in area and the areas of seepweed marsh and rivers remained almost unchanged thus cutting the proportion of mudflat from 65.44% to 26.85. in the years to follow, the expansion of Spartina alterniflora marsh will slow down, while the other types of wetlands will keep going along their course of evolution. The wetland landscape will evolve in composition from three belts (reed marsh – seepweed marsh - mudflat) to four belts (reed marsh – seepweed marsh - Spartina alterniflora marsh - mudflat).
Species Diversity and population Distribution in Edge of Typical Oasis of the Lower Reaches of Tarim River
LIU Xin-Hua, XU Hai-Liang, ZHAO Xin-Feng, WANG Wei
2011, 27(3):  53-57. 
Abstract ( 941 )   PDF (706KB) ( 1454 )  
Related Articles | Metrics
Investigation were carried out on vegetations of seven sections of the edge of an typical oasis of the lower reaches of the Tarim River in the summer of 2008, using the transect and quadrat method, variation of the species diversity under a habitat gradient was analyzed, using α diversity index (richness index, Shannon-Wiener index, Simpson index, Pielou index) and β diversity index (Whittacker index, Cody index), and characteristics of population distribution patterns were explored quantitatively of ten plant species in the region, using through five population distribution pattern indices (dispersion index, negative binomial parameter, mean congestion degree, clumping index and patchiness index). Results show that species diversity of the region was affected by soil moisture and soil salinity and species richness on the whole was kept at a low level. Its α diversity index followed the order of oasis > transition zone > mobile-dune, and so did β diversity index. The analysis of population distribution patterns revealed that the ten plant species all show aggregated distribution. Cluster distribution of the plant population in arid regions reflects their adaptability to the habitat.
Point patterns of Colonies of Three Common Sand-Binding Plants in the Mu Us Sandy Land
CUI Qiang, GAO Jia-Rong, LI Bai, QIAN Bin-Tian, LIU Fa, ZHANG Jin-Rui
2011, 27(3):  58-63. 
Abstract ( 909 )   PDF (1011KB) ( 1344 )  
Related Articles | Metrics
Artemisia ordosica, Hedysarum laeve and Hedysarum scoparium are three common sand-binders in North China, and are usually air-seeded in mixture. Distribution patterns of colonies of the three aerial-seeding plants were studied to explore intra-species and interspecies correlation, with the aim of providing a theoretical basis for future aerial seeding in the Mu Us Sandy Land. Two 50 m × 50 m typical samples plots different in aerial seeding time were selected as research subjects in the Mu Us Sandy Land, Ningxia. Ripley’s K function bivariate point pattern analysis method was applied to finding spatial correlation between the plants. Results show that A. ordosica, when seeded in monospecies, is better off if seeded in clusters and controlled in quantity. Seeds density of H. laeve should be controlled in aerial seeding. Usually in scattered distribution, H. scoparium should be seeded in mixture with others. H. laeve and H. scoparium can be seeded together, with the former as the mainstay. Obvious negative correlation was found between A. ordosica and H. laeve, so they are not suitable for mixed seeding. Neither are A. ordosica and H. scoparium.
Effects of Vermicompost as Turf-Bed Substrate Modifier on Creeping Bentgrass
WANG Xiao-Zhi, WANG Ai-Li, WANG Shou-Hong, ZHAO Hai-Tao, DAN Yu-Hua, QIAN Xiao-Qing, FENG Ke
2011, 27(3):  64-68. 
Abstract ( 785 )   PDF (739KB) ( 1329 )  
Related Articles | Metrics
Influence on the properties of turf-bed and growth of creeping bentgrass based on cow-manure-vermicompost as the basic materials were studied to determine the feasibility and effectiveness of cow-manure-vermicompost as substrate modifier of the turf-bed. The results show that pH value of the turf-bed decreased with an increasing addition of vermicompost while conductivity (σ) value remarkably increased. Conductivity value in 100 g•kg-1 vermicompost treatment was about 16 times of that in CK. But after the turf establishment stage, conductivity values decreased to the level close to that of CK. Compared with addition of 40 g•kg-1 peat, the addition of 40, 60, 80 and 100 g•kg-1 vermicompost can significantly shorten the time of the formation process of the lawn, considerably increase the regeneration speed, and remarkably improve the chlorophyll content and the clipping content. The growth of grass in vermicompost treatments was better than that in peat treatment. During actual performance, it should be considered that the growth of grass may be too fast at the later stage due to the higher content of phosphorus in vermicompost.
Relationship Between Wetland Plant Communities and Water Environment Quality in Xixi Wetland Park
CAO Xiao, LIU Hong-Yu, LI Yu-Feng, ZHENG Nan
2011, 27(3):  69-75. 
Abstract ( 1241 )   PDF (1138KB) ( 1601 )  
Related Articles | Metrics
Based on classification of the wetland vegetation coverage in the Xixi Wetland Park, relationship between plant communities and water quality were studied. Results show that the park has 16 species of wetland plants, belonging to 16 genera, 13 families, and is low in species richness. When vegetation coverage of the wetland is maintained at a low (1% - 20%) or moderate level (>40% - 60%), its water quality was kept at a relatively good level. It seems that a higher vegetation coverage is not at all conducive to maintenance of a good water quality. Based on analysis of relationships of common plant communities (ca 40% in coverage) with water quality, the plant communities can be sorted into 3 types, i.e. Type I : Iris tectorum + Alternanthera philoxeroides and Arundo donax + A. philoxeroides, and Thalia dealbata + A. philoxeroides, where chemical indices of the water were all very high, indicating that the water environment is very poor in quality; Type II : A. philoxeroides, Zizania latifolia + A. philoxeroides, and Thalia dealbata + A. philoxeroides, where the water environment is at a moderate level in quality; and Type III : Phragmites australis + A. philoxeroides, where the water environment is relatively good. Therefore, reestablishment of vegetation of native plants, like P. australis and maintenance of a proper vegetation coverage, low or moderate is recommended to keep the water in good quality in wetland park.
Effect of Periphyton in Artificial Substrate on the Purification of Eutrophicated Water
LU Hong, CHAO Jian-Ying, ZHANG Yi-Min, KONG Xiang-Ji, CHEN Qian, LI Ding-Long
2011, 27(3):  76-81. 
Abstract ( 928 )   PDF (930KB) ( 1321 )  
Related Articles | Metrics
Features of periphytons in artificial substances for purifying eutrophicated water of algae and nutrient substances, like nitrogen & phosphorus were studied and influence of physical & chemical properties, like water depth, water flow velocity, DO, temperature and pH, on the purifying effect were analyzed. Results show that in still waterbody, the mean removal rate of NH4+-N、TN、TDN、NO3--N、TP、TDP、PO43--P was 98.90%、45.15%、42.78%、38.13%、76.18%、80.11%、87.02%, respectively, and Chl-a content decreased by 63.53%. Water depth affected the decreacing speed of Chl-a to some extent, but did not affect the removal rate of other nutrients. Water flow velocity, once increased from 0 to 200 L•h-1, raised the removal rate of TP, TDP to a certain extent, from 76.18% to 85.13%; and from 80.11% to 83.76%, respectively, while Chl-a content was raised by 63.53% in still water, and by 72.17% in dynamic water. However, it lowered that of TN, TDN and NO3--N from 45.15% to 32.02%; from 42.78% to 28.73%; and from 38.13% to -5.26%, respectively, and did not affect much that of NH4+-N and PO43--P (NH4+-N: from 98.90% to 98.59%; and PO43--P: from 87.02% to 86.13%). Among the physical & chemical properties, DO was also a factor affecting the purifying effect.
Modeling of Water Circulating Pond Aquaculture System and Its N & P Removal Effect
HU Geng-Dong, SONG Chao, CHEN Jia-Chang, WU Wei, MENG Shun-Long, FAN Li-Min, GE Xian-Ping
2011, 27(3):  82-86. 
Abstract ( 966 )   PDF (877KB) ( 1497 )  
Related Articles | Metrics
A model of water circulating pond aquaculture system for fish rearing was constructed and tested, including water source, fish pond, eco-canal (first-level purification), second-level purification pond and third-level purification pond, and its effect of removing nitrogen and phosphorous was studied. The test-running of the model from May to October 2010 showed that after three levels of purification, the concentration of ammonia nitrogen in outflowing wastewater from the system was maintained around 0.33 mg•L-1 and even lowered down to 0.010 3 mg•L-1 in June, and the concentration of nitrite nitrogen was kept lower than 0.02 mg•L-1, making the concentration of total nitrogen meet the criteria of Grade V of the Standard for Surface Water Environment Quality (GB 3838-2002), and the concentration of total phosphorous the criteria of Grade III of the Standard for Surface Water Environment Quality. The effect of the model removing chlorophyll-a was also very obvious, ranging from 16.10% to 91.22% in rate. It is clear that the model could remove surplus ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorous and chlorophyll-a from the wastewater. But, in this experiment, the purification ponds did not show their function of effect multiplier level by level, maybe due to the excessive density of aquatic plants as a result of poor management, which led to fluctuation of water quality. The test in the past two years demonstrates that the model of water circulating pond aquaculture system is still in the process of improving functionally, but has not yet got mature.
Effects of Amendments on Quality and Physiological Characteristics of Young Soybean Grown in Soil Contaminated by Heavy Metals in Combination
WANG Yi-Kun, FANG Sheng-Zuo, WANG Yu-Jun, HAO Xiu-Zhen, ZHOU Dong-Mei, ZHANG Huan-Chao
2011, 27(3):  87-92. 
Abstract ( 832 )   PDF (1155KB) ( 1259 )  
Related Articles | Metrics
Effects of soil amendments, including attapulgite (25 g·kg-1)、 diatomite (25 g·kg-1)、peat (25 g·kg-1)and humic acid(4 g·kg-1)on growth, quality and philological characteristics of young soybean grown in soil contaminated with heavy metals in combination were studied through pot experiment. Results show that compared with the clay minerals (diatomite and attapulgite), the organic materials (humic acid and peat) significantly increased yield and crude proteins content of the grains, and improved their eating quality. All the amendments mitigated the toxicity of heavy metals to plant. Humic acid, peat and attapulgite obviously increased SOD activity in leaves of the plants at the seeding stage (P<0.05),but diatomite did not, till the plants reached the maturing stage. Among the amendments, only humic acid increased significantly chlorophyll content in leaves of the plants at the seedling and maturing stages (P<0.05). And humic acid was also the most effective in lowering contents of heavy metals in grain and decreased the content of Zn, Cu, Cd and Pb by 28.8%,21.6%,35.0% and 12.5%, respectively, as compared with CK. Diatomite followed in the effect, however peat and attapulgite did not show any significant effect in this aspect.
Impact Assessment of Highway Construction on Ecological System Stability in Ecological Sensitive Area
WANG Yang, SUN Qin-Fang, ZHU Ling
2011, 27(3):  93-97. 
Abstract ( 883 )   PDF (752KB) ( 1439 )  
Related Articles | Metrics
Based on the concept of ecological system stablity,relationships of highway construction with key factors of ecological system stability in ecological sensitive areas were analyzed.Spatial patterns of landscape ecology,level of natural productivity and density of dominant biological species were found to be the key factors.A framework and methods for evaluation of impact of highway construction on ecological system stability of the area were put forward.The framework and methods were applied to the study on impact of the construction of Highway 121 that passes through the National Hongze Lake Wetland Reserve.
Determination of Chlordane Residue in Aquatic Products With Gas Chromatography
CHEN Jie-Wen, KE Chang-Liang, GAN Ju-Li
2011, 27(3):  98-102. 
Abstract ( 821 )   PDF (797KB) ( 1283 )  
Related Articles | Metrics
To establish a method for determination of cis-chlordane,trans-chlordane and oxychlordane in aquatic products with gas chromatography,edible parts of fish,shrimps and shells were used for the test.One granm of homogenized tissues was treated with acetonitrile,extracted ultrasonically,stripped with hexane,and refined through a Florisil silica-gel column.And the outflow from the column was analyzed on a gas chromatograph equipped with electron capture detector for determination of chlordane.The linear range of chlordane concentration was from 0.200 to 100g•L-1(r=0.998 3~0.999 9,n=7,P<0.001),and the detection limit for the three species of chlordane was all 2.00 ug•kg-1(in wet weight).When the sample was added at a rate of 1 to 15 times as much as the quota,the recovery rate of the sample ranged from 72.2% to 104.0% based on 6 repeated determinations.Variation coefficient varied from 2.81% to 8.56% in each batch(n=6)and was 8.50% between batches(n=3).
Weight of Land(Soil)Degradation Indices and Optimization of Their Calculation in “Technical Criteria for Evaluation of Ecological Environment(Trial)”
YANG Bao-Hua, YANG Qing-Hua, CHEN Jian-Hong
2011, 27(3):  103-107. 
Abstract ( 901 )   PDF (529KB) ( 1481 )  
Related Articles | Metrics
Based on analysis of the technical route of the weighted normalized indices in“Technical Criteria for Evaluation of Eco-Environment”(HJ/T 192-2006),a conclusion was reached logically contradicting the specifications of HJ/T192-2006,regarding land degradation, land degradation index and ecological environment index(EI).On such a basis,two computation methods,i.e.“adjusted erodibility enpowering order method”and “minusing land degradation grading index method”were brought forth and verified.Analog computation using the methods demonstrates that of two plots similar in the proportion of moderate or severe erosion,the one higher in the proportion of light erosion is higher in EI of the two plots similar in the proportion of light erosion the one with higher proportion of moderate eronsion is higher in EI.It was found that the outcomes of the computation using the two methods tallied with the common logic of evaluation of eco-environment and were highly synchronus in statistical check,demonstrating that both methods are applicable to practical evaluation of eco-environment.
Pollution of Waterbody by Chlorpyrifos Used in Paddy Rice Field in Hilly Areas and Its Ecological Risk
WU Chang-Xing, ZHAO Xue-Ping, WU Sheng-Gan, CHEN Li-Ping, WANG Yan-Hua, WANG Qiang, WU Min
2011, 27(3):  108-112. 
Abstract ( 1028 )   PDF (698KB) ( 1388 )  
Related Articles | Metrics
A small scale field experiment in a hilly area was carried out to investigate dates and doses of chlorpyrifos sprayed in paddy fields during the rice growing season in that region,and residues of chlorpyrifos in irrigation and drainage waters of the paddy fields were measured at various rice growing periods.It was found that chlorpyrifos residue level was higher in the drainage water than in the irrigating water,and 26.07ug•L-1.The irrigation water diverted from rivers was also found to have chlorpyrifos residue,with the highest reaching as high as 3.23ug•L-1,indicating that the river water had already been polluted by chlorpyrifo from its use in paddy fields in the river's upstream area.The acute toxicity ρ of chlorpyrifos was determined to be 1.11mg•L-1(96 h-LC50)to zebrafish,1.44ug•L-1(48 h-EC50)to Daphnia magna and 0.193mg•L-1(72 h-EC50)to algae.According to the acute risk assessment criteria established in the European Union(EU)legislation,chlorpyrifos is determined to be low in risk to fish and algae,but is risky to Daphia magna in the waterbodies around paddy fields.