In order to explore the way of water spinach planting in floating bed affecting the water micro-ecological environment of tilapia aquaculture ponds, water spinach floating beds were set up in the ponds under the 10% coverage. These ponds served as the treatment group, while the other ponds without floating beds served as the control group. After the vigorous growth of water spinach, the samples of water from treatment ponds, control ponds, and the samples of water spinach roots were collected respectively. The DNA of the samples was extracted, part of them was used to amplify the 16S rRNA genes and carry out the high-throughput sequencing, to investigate the effect of water spinach planting on the bacterial community structure in water, and analyze the relationship between the root system of water spinach and the bacterial community structure of surrounding water. Another part of DNA was used to conduct the fluorescent quantitative PCR to determine the copy number of nitrogenase gene, and analyze the effect of water spinach planting on the nitrogenase genes in tilapia aquaculture pond ecosystems. The results showed that the direct effect of water spinach planting on the community structure of planktonic bacteria in the water was not significant; however, the root biofilm of water spinach played an important role as a key part of the pond micro-environment. At the same time, water spinach root biofilm also increased the number of nitrogen-fixing microorganisms per unit volume in pond water.

In this paper, we optimized the determination method for geosmin (GSM) and 2-mathylisoborneol (2-MIB) in aquaculture water and aquatic products by using the method of microwave distillation - solid-phase microextraction - gas chromatographic-mass spectrometry (MD-SPME-GC-MS). We optimized the four pre-treatment processing parameters, including carrier gas rate, microwave power, distillation time and collection method, and determined the experimental conditions as follows: carrier gas rate of 60 mL/min, microwave power of 400 W, distillation time of 6 min, and constant of 250 mL. In aquaculture water, the detection limit of GSM and 2-MIB reached 1 ng/L and 10 ng/L, respectively. In aquatic products, the detection limit of GSM and 2-MIB reached 0.025 μg/kg and 0.25 μg/kg, respectively. The standard curve of this method had good liner relation in the range of 1-200 ng/L and 10-200 ng/L (R² was 0.9997 and 0.9982, respectively). The average recovery rate of GSM and 2-MIB at different concentrations (1, 5, 7, 10, and 20 μg/kg) was 45.28%-49.92% and 82.15%-87.36%, respectively. In this experiment, the water samples and aquatic product samples from Wuxi were detected by this method. The result showed that the average concentration of GSM and 2-MIB in the water samples was 19.58 ng /L and 58.29 ng /L, respectively. In aquatic products, only GSM was detected, and the average concentration was 0.61 μg/kg. This method can be widely used to detect fishy substances in aquaculture water and aquatic products.

This study analyzed the data of water quality and nitrogen and phosphorus in sediment from 84 black and odorous water bodies in rural area of Chongqing, and evaluated the current situation of pollution in water and sediment by comprehensive pollution index method and organic index method. The results show that 87% of black and odorous water bodies have nitrogen and phosphorus pollution, and 50% have excessive nitrogen and phosphorus at the same time, the nitrogen pollution is more serious in brooks and ditches than that in pond. The sediments are 100% polluted by TN, ON and TP, and 70.2% polluted by organic pollutants. There is a significantly positive correlation among the indicators of TN, TP and NH₃-N. OM, TN and TP in the sediment show no significant correlation between each other. In general, the black and odorous water bodies in rural area of Chongqing are mainly polluted by exogenous sources.

The bioflocs shrimp culture system was used to culture M. japonicus and investigate the efficiency and stability of nitrogen conversion in the biofloc system during abrupt temperature change. In the experiment, M. japonicus was randomly divided into 2 groups. The control group was disinfected clean seawater with a daily water exchange rate of 20% (semi-closed culture system), and the experimental group was biofloc seawater with an initial volume of 20 mL/L (biofloc floc culture system). After the water quality of the experimental group and the control group remained stable for one week, the temperature mutation stress was applied, and the temperature rose sharply by 10℃. The results showed that there was no significant effect of abrupt temperature change on the nitrogen conversion pathway in the biofloc system during the experiments, and the nitrate nitrogen in the experimental group showed an increase after abrupt temperature change, from 19.65 mg/L on the 5 d of the experiment (before abrupt temperature change) to 31.54 mg/L on the 10 d (after abrupt temperature change), and the cumulative rate was greater in the experimental group than in the control group. High-throughput sequencing revealed that a total of 4219 OTUs were obtained in both experimental and control aqueous organisms. The abundance and diversity indices were greater in the experimental group than those in the control group, and greater before than after abrupt temperature change. Microbial communities in the water and gut after temperature mutation were lower in abundance and diversity than before abrupt temperature change. Bioflocs system performed better than semi-closed culture system in coping with abrupt temperature change, with higher stability in both abundance and diversity of microbial communities.

To study the effects of different feeding rates on the growth, water physicochemical indexes and microbial community metabolic diversity of cultured tilapia, 16±0.20 g Oreochromis niloticus was used as the research object, the effects of different feed rates on tilapia growth and water quality indicators were explored. Biolog-ECO method was used to detect the utilization of 31 carbon sources by microorganisms in culture water samples, to study the differences of microbial metabolic diversity under different feeding rates. The results showed that the tilapia with 4% feeding rate had the lowest feed coefficient and relatively high feed utilization rate; high feeding rate had a relatively great impact on water quality, and different feeding rates had an impact on microbial metabolic diversity in aquaculture water; the Shannon index of 4% feeding rate was relatively high, and there were more kinds of microorganisms in water; Pearson correlation analysis showed that COD, TN, TP, NH₃-N had strong positive correlations (P<0.05) with water microbial metabolic diversity metabolism of β-methyl-D-glucoside, glucose-1-phosphate, glycyl-L-glutamic acid. In the process of tilapia culture, considering both ecological and economic benefits, we should feed the tilapia with proper feeding rates, the feeding rate with the initial tilapia size of about 16g is around 4%.

To investigate the microbial communities’ structure of water and intestine of black sea bream (Acanthopagrus schlegelii) reared in in-pond raceway culture system (IP) and pond (EP), intestines and culture water were selected as research objects. Using high-throughput sequencing technology, the structure and function of bacterial communities under the two different culture modes were compared and analyzed. The results show that the microbial communities are mainly composed of Proteobacteria, Actinobacteria, Cyanobacteria, Firmicutes, Bacteroidetes and Chloroflexi, and the sum of their abundance is 98.32%-99.22%. At genus level, bacteria are significantly different. Furthermore, the main increased species in IP mode were Ruegeria (14.84%) Synechococcus (14.24%), Marivita (3.58%), norank_o__PeM15 (2.97%) and norank_C__KD4-96 (2.56%)(P<0.05) (IP > EP). However, the main bacteria in EP model are Enterobacter (10.31%), Mycobacterium (10.30%), Romboutsia (7.37%), Enterococcus (6.29%) and Lactococcus (5.38%) (P<0.05) (IP < EP). The bacterial community in intestine has high richness and diversity, IP mode is significantly higher than that in EP mode (P<0.05), but there is no significant difference between fish intestines (P>0.05). There are differences in the structure and function of the flora under the two culture modes, and there are a large proportion of bacterial communities with significant differences in relative abundance. Most of the dominant bacteria with significant differences are beneficial bacteria in the intestine of black sea bream in IP mode, while in the EP mode, the bacteria are mostly chronic or conditional pathogens.

【Objective】The investigation and analysis of agricultural non-point source pollution status in typical small watershed of Danjiangkou Reservoir Area were conducted to parse the pollution load and pollution sources of non-point agricultural sources in this area, so as to provide the reference for formulating targeted prevention and promoting the green development of agriculture. 【Method】Field visits were carried out through questionnaire survey in the Tanjiawan watershed, and the pollution sources, such as planting, breeding and living, were classified in two villages. Meanwhile, the pollution load was estimated according to the export coefficient method approach and the equivalent standard pollution load method. 【Result】The results showed that: the actual load of agricultural non-point source pollution in Tanjiaban watershed decreased from 162.32 t in 2015 to 27.79 t in 2020, the total equivalent standard pollution load decreased from 62.44 m³ to 21.14 m³, and the dominant source of pollution changed from land utilization to livestock and poultry breeding. The total annual loads of TN, TP and COD of agricultural non-point source pollution in the watershed were 5.56, 0.86 and 21.37 t, respectively. The contribution of different pollution sources were found in the following order: livestock and poultry breeding > land utilization > rural life. TN, TP and COD load of pig breeding accounted for 50.91%, 64.20% and 46.66% of the total load of the watershed, respectively, making it the most important source of pollution in the region. TN was the most important non-point agricultural source in the watershed, and its equivalent standard pollution load accounted for 52.6% of the total load, followed by TP, with a pollution load rate of 40.7%, and the minimum equivalent standard pollution load rate of COD was 6.7%. According to the result of environmental pollution risk assessment, the alarm value of livestock and poultry manure load in Tanjiawan watershed was 0.489 and the risk level wasⅡ, indicating the environmental pollution was "slightly". There was still room for expansion of 10 815 pig’s equivalent on the basis of the current total amount of cultivation in the watershed. Since 2015, the intensity of non-point agricultural source pollution in Tanjiawan watershed has been reduced significantly. 【Conclusion】It was of great significance to keep a reasonable amount of livestock and poultry breeding, and to take some effective measures to promote the sustainable emission reduction of non-point agricultural source pollution in the typical watershed of the Danjiangkou Reservoir area.

By adding Chlorella to tilapia aquaculture water, this study aims to explore the optimal concentration of Chlorella for the degradation of N and P and the regulation of microbial community in aquaculture water. Control group (NC), low concentration group (LC), middle concentration group (MC) and high concentration group (HC) were set to explore the effects of different concentrations of Chlorella on reducing the concentration of N and P in tilapia aquaculture water. The 16S rRNA high-throughput sequencing technology was used to analyze bacteria community structure changes of aquaculture water body. Compared with other treatment groups, N and P nutrition of water body in HC group decreased, and the degradation rate of nitrogen in three forms was NH₄⁺-N>NO₃^--N>NO₂^--N. Compared with NC group, the microbial diversity of MC and HC group decreased. The relative abundance of Proteobacteria in each treatment group increased, while that of Bacteroidetes decreased, and the relative abundance of Bacteroidetes in HC group was the highest, the community richness was significantly correlated with the content of NH₄⁺-N. In summary, Chlorella can absorb N and P nutrition from aquaculture water, regulate aquaculture water microbial community structure, and improve aquaculture water quality. The study could provide a theoretical basis for aquaculture production practice.

The purpose is to analyze the metabolic diversity of microbial community and the impact of environmental factors on it, so as to provide reference for the improvement and restoration of ecological environment in the lower reaches of the Yangtze River. Biolog-ECO technology was used to analyze the microbial metabolic diversity in the lower reaches of the Yangtze River, and to explore the relationship between the changes of physical and chemical factors of water quality and the metabolic diversity of microbial communities. The results showed that except TP and TN, other water quality indexes in the lower reaches of the Yangtze River met the above class II standards; the overall metabolic capacity of the microbial community in Anqing and Nanjing river sections was relatively strong; the richness index of microbial community was the highest in Nanjing river section; the sequence of diversity index and evenness index from high to low was Anqing river section, Nanjing river section, Jingjiang river section, Tongling river section and Wuhu river section. The results of RDA analysis showed that TP and Pb were positively correlated with the six major carbon sources. Based on the analysis of water quality index and microbial metabolic diversity, the eutrophication degree of Anqing and Nanjing river section is relatively high, and TP and Pb can promote the metabolic diversity of microbial communities in the lower reaches of the Yangtze River.

The aim is to investigate the elimination patterns of enrofloxacin in the lower water column of the fishery and the production of the metabolite ciprofloxacin, since antibiotics entering the water column are prone to accumulate in the lower water column or in the substrate sediment, and cause adverse effects on aquatic life. Common environmental factors (temperature and pH) in the fishery water were selected for the experiment, and effects of these two environmental factors on the degradation of enrofloxacin (ENR) in aqueous humor were investigated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with orthogonal experiments, and the production and changes of the metabolite ciprofloxacin (CIP) were detected. The experimental results showed that the half-life variation of ENR in the nine treatment groups ranged from 13 to 32 d and the elimination rate ranged from 44% to 80%. Root ANOVA knots showed that pH changes had a significant effect on the degradation of enrofloxacin, while temperature changes did not have a significant effect, with the highest elimination rate of enrofloxacin at 25°C and pH 5. In addition, the production of ciprofloxacin was detected during the experiment, which reached the highest concentration (10.8 ng/mL) at pH 5 and 25°C on day 7 from the beginning of the experiment, and then gradually decreased to the concentration 0-0.16 ng/mL on day 26. This study clarifies the influence of environmental factors on enrofloxacin degradation and provides some theoretical guidance for reducing enrofloxacin residues in aquaculture environment.

To study the suitable plants for N and P purification in aquatic water, Eichhornia crassipes, Spirodela polyrrhiza and Ipomoea aquatica were selected as test subjects. The biomass gradients were set up. The water samples were taken once every 5 days. The indexes of N and P such as TN, NO₃^-, NO₂^-, NH₄⁺-N and TP in aquatic water were determined and analyzed. The effects of different plants, biomass gradients and experimental time on N and P purification were studied. The results showed that the three plants grew normally and had good purification capacity for N and P in aquatic water. The three plants had better effect on N purification in 10-15 days, and on P purification in 15-20 days. The biomass of Eichhornia crassipes, Spirodela polyrrhiza and Ipomoea aquatica with the best purification effect on N and P was 2000-2500 g/m ³, 150-200 g/m ³ and 800-1600g/m ³, respectively. All the three kinds of plants can be used to purify N and P of aquatic water, the order of the purification effect on TN, TP, NO₃^- was Ipomoea aquatica > Spirodela polyrrhiza > Eichhornia crassipes, while on NO₂^-、NH₄⁺-N was Eichhornia crassipes> Ipomoea aquatica > Spirodela polyrrhiza. Eichhornia crassipes is more suitable for the purification of N and P in aquatic water.

Methomyl is a highly toxic pesticide, which can contaminate aquaculture water by means of surface leaching. To study the purification efficiency of water spinach on methomyl in the water body and other water quality indexes and investigate the impact of water spinach on tilapia, we took methomyl, tilapia, water spinach and indoor cultivation system as test materials to measure the water quality indexes according to the Water and Wastewater Monitoring Analysis Methods. The methomyl concentration in the water body was measured by the Liquid Chromatograph Mass Spectrometer (LC-MS), and the glutathione (GSH) content (the DTNB method), superoxide dismutase (SOD) content (WST-1 method) and catalase (CAT) content (the Ultraviolet Spectroscopy) were measured using the assay kit. The results showed that the growth rate of tilapia decreased with the increase of methomyl concentration in water. Methomyl contamination led to increasing the oxidative pressure of the tilapia liver, and caused the changes of SOD, CAT and GSH. Water spinach could effectively reduce the content of methomyl in the aquaculture water through body absorption, it purified TN, NH₄⁺-N, NO₃^--N and NO₂^--N in the water contaminated by methomyl to a certain extent and reduced the oxidative stress of the tilapia liver. The study reveals that water spinach grown in water can effectively reduce the pollution of methomyl and ensure fish growth.

To build an eco-friendly fishery with green low-carbon developmental concept and high-efficient, high-quality, ecological, healthy and safety developmental target, the authors review the structural properties of enrofloxacin and ciprofloxacin and its pharmacokinetic metabolism studies in livestock and aquatic animals; summarize the effects of enrofloxacin on aquatic organisms including phytoplankton and microorganisms; clarify the elimination and degradation pathway of enrofloxacin and its metabolites; point out the migration and transformation of enrofloxacin and its metabolites in fishery waters, thus to provide a guidance for farmers to use enrofloxacin safely and rationally, reduce pollution to the ecological environment, and make a contribution to developing green, sustainable and ecological fishery.

In order to explore the natural degradation rule of sulfamethoxazole (SMZ) in aquaculture water, this experiment selected common factors in aquaculture water environmental (temperature, pH and open or cover system conditions), and explored influence of these three factors on the dynamic digestion of SMZ in natural aquaculture water through orthogonal experiment. The SMZ concentration of each treatment remained consistent in the initial stage of the experiment. Water samples were taken regularly to detect the change of SMZ concentration in water body, which is consistent with the first-order kinetic equation,and the half-life and elimination rate of SMZ in each treatment were calculated. The results showed that the variation range of SMZ half-life and its elimination rate in 18 treatment groups was 4.88-12.89-d, 28%-77%. Anova analysis showed that within the range of the experimental level, temperature and pH factors had a significant influence on SMZ elimination, but the influence of the open or cover condition was small. Therefore, properly adjusting the conditions of temperature and pH of aquaculture water was conducive to promoting SMZ degradation.

To control water environmental ecology and ensure the safety of water source, we assessed the individual health hazard risk of genetic toxic and body toxic substances by applying the health risk assessment model based on measured data of water quality in Guxian reservoir. The results showed that: (1) the annual individual health hazard risk of all kinds of pollutants was 4.24×10-5 from 2009 to 2015 in the reservoir, which was lower than the maximum acceptable annual value of 5.0 × 10- 5/a recommended by the International Radiation Protection Committee, but higher than the risk value of 1.0 × 10- 5/a suggested by Sweden and Netherlands; (2) through drinking water, the risk value of carcinogenic substances to human health hazards was: Cr>As>Cd, and the risk value of non-carcinogenic substances was: F->Cu>Pb>Hg>NH3-N>CN->Se>Zn> phenol; the risk of carcinogens was more dangerous to the human body than that of non-carcinogens. It is necessary to strengthen soil and water conservation work, strictly prevent agricultural non- point sources pollution, promote scientific breeding, to ensure the safety of drinking water.

The objective of the study was to screen the ecological floating island plantation model that has a good purification effect on the rivers in the villages of Handan City. Mainly studied under static conditions, the effect of ecological floating islands with different combinations of different plants on the purification of rural rivers, select Eichhornia crassipes, Thalia dealbata, Canna indica, Sagittaria and Oenanthe javanica as test plants, and compare the removal efficiency of COD, TP, NH4+-N and other pollutants in water by five combinations. After 38 days of testing, the results show that: Oenanthe javanica + Sagittaria + Canna indica+ Eichhornia crassipes, Canna indica + Thalia dealbata + Eichhornia crassipes had higher removal rates of COD, which were 35.5% and 31.2%, respectively. The removal rate of TP was higher with Oenanthe javanica + Sagittaria + Canna indica + Eichhornia crassipes, Canna indica + Thalia dealbata + Eichhornia crassipes, which were 81.6% and 77.3% respectively. The removal rates of NH4+-N were higher with Oenanthe javanica + Sagittaria + Canna indica + Eichhornia crassipes, Eichhornia crassipes + Thalia dealbata + Canna indica + Oenanthe javanica, which were 55.4% and 53.9%, respectively. The mixed plant-type ecological floating island has a significant effect on the purification of rural river water bodies.

Green production plays a key role in maintaining ecological safety of ecologically sensitive areas. This study established a synthetic index system of ecological compensation standard by calculating the evaluation of ecosystem service values, environmental cost and extra cost based on the ecological, economic, environmental and social dimensions. This paper calculated the compensation standard of conventional and ecological kiwifruit in water conservation area of South-to-North Water Diversion Project in 2015. A face to face questionnaire’s investigation of the willingness to accept (WTA) was conducted focused on the ecological compensation of kiwifruit planting with option of half of both fertilizer and pesticide and option of zero fertilizer and zero pesticide. Then comparing the compensation standard values with the WTA values by contingent value method, the results showed that the WTA value with fewer fertilizers and fewer pesticides was 16524 yuan/(hm2·a), which is much smaller than the compensation standard value 24105.5 yuan/(hm2·a), while the WTA value with zero fertilizer and pesticide was 28983.9 yuan/(hm2·a), which is higher than the compensation standard value. It is clear that the WTA expectation of farmers for organic planting pattern was much more than the green planting pattern. More financial and technical input should be considered to fulfill the conversion from conventional agriculture to organic agriculture.

Pesticide played an extremely important role in agriculture, but pesticides discharged into the water by spraying, surface runoff and factory waste water and it had brought serious pollution and harm to water, at the same time, the water environment problem was increasingly outstanding. In order to maintain the ecological balance of water environment, there was a great significance to study the pollution and degradation of pesticides in water. In this paper, the pollution and degradation of pesticides in water were summarized, and the problems of pesticide degradation in water and the future research directions were put forward.

The difference in functional diversity of aquatic microbial community in tilapia ponds under different food intake conditions was examined in this paper. Biolog method was used to study the utilization of six carbon sources, and the relationship between functional diversity and environmental factors in microbial communities of tilapia aquaculture ponds. The results showed that utilization of both alcohols and amines by microbes in the tilapia ponds under different food intake conditions was significantly different, while the utilization of other carbon sources was basically the same. RDA analysis revealed that NH4+-N, NO2--N, NO3-- N were the main environmental factors influencing functional diversity of microbial community in tilapia ponds under different food intake conditions. The results indicate that there are some differences in functional diversity of microbial communities in tilapia ponds under different food intake conditions.

In order to study the elimination technology of heavy metals in fishery water, the sources of heavy metal pollution were reviewed, mainly from industrial development, agricultural pesticides and fertilizer, and urbanization. The harm of fishery water pollution, which has a certain destructive effect on aquatic ecosystem and risks on quality of aquatic products and human life, was elucidated. Currently, there are mainly three ways for eliminating water heavy metals, including physical, chemical and microbiological ways. The combined utilization of plants, microorganisms and chemical materials could be the new direction for heavy mental elimination. Finally we pointed out the shortages of the related studies, such as the final treatment of heavy metals, which should be further studied.

Taking the negative ion concentration of water in Sun Island as the objects of study, [Objective][Method]Applying ArcGIS to interpolate the negative ion concentration of Solar Waterfall and Solar Lake in Sun Island, Harbin, and analyzed the distribution characteristics of negative ion concentration in different types of water bodies.[Objective]The correlation between the concentration of negative ion in the lake with temperature and humidity were studied.[Result] It was found that the negative ion concentration of the lake was positively correlated with the temperature and humidity,[Method]The optimal function model of negative ion concentration with temperature and humidity in the Sun Lake area were fitted by SPSS, and the significance test were carried out with the significance level of 0.01.[Objective][Method]The air cleanliness of Sun Waterfall, Sun Lake, Swan Lake and Wetland Garden in Sun Island Scenic Area were evaluated by means of air quality evaluation index.[Result]The evaluation result shows that the air cleanliness level of the Solar Waterfall, the Swan Lake and the Wetland Garden are Grade A, the air quality reach the cleanest standard, the air cleanliness level of the Sun Lake is Grade B, and the air quality has reached the standard of general cleaning,[Conclusion]which can be used as a reference for the study of air negative ions.

The paper aims to master the pollution levels of heavy metals in the Yangtze River Basin. The authors selected Anhui and Jiangsu sections in the Yangtze River as sampling points, and collected 16 water samples in June 2016 to determine the contents of 6 heavy metals. The heavy metal contents in the water samples were determined by atomic absorption spectrophotometer. The results showed that: there were no residual Cd in the collected water samples, and the other heavy metals had varying degrees of residues; the residual mean value of Cr, Pb, Cu, Hg and As was 4.276, 1.866, 5.762, 0.016, 1.421 μg/L, respectively; as a whole, higher levels of heavy metals were found in Anqing and Jingjiang, followed by Nanjing and Tongling, while the pollution in Wuhu was the minimal; the Cr pollution in Jingjiang, Anqing and the Hg pollution in Tongling Site 1 reached tertiary level; secondary pollution area was mainly with Cu, Pb level in Tongling Site 1 also reached secondary pollution level, while the otherelements’ pollution was insignificant. This study provides a basis for the effective control of heavy metal pollution in the lower reaches of the Yangtze River, and the realization of scientific management of water environment health risk, and has technical data support for quality and safety assessment of aquatic products.

Reed is perennial wetland vegetation, whose root has the ability to release oxygen and oxidants into the rhizosphere, and form iron oxides at the root surface or rhizosphere. According to the amphoteric colloid ability of reed root biogenic iron oxides, the iron oxides were used as adsorbing material obtained by the methods of both direct obtaining and high temperature carbonization, the adsorption effect of this material to pentavalent arsenic [As (V)] was studied by isotherm method. The results showed that the As (V) adsorption ability of iron oxides under acidic condition was significantly higher than that in neutral or alkaline condition. The adsorption content increased with the increase of As concentration in the external medium solution, when the As concentration was 200 mg/L, the adsorption content of two iron oxides treatments reached (17.00±3.25) and (12.82±1.01) mg/g, respectively. The adsorption of As by iron oxides could be well described by Langmuir and Freundlich isothermal adsorption model. The maximum adsorption amounts of As obtained by Langmuir isotherm equation were (17.72±1.09) and (21.94±6.74) mg/g, respectively. Therefore, the biogenic iron oxides had strong absorption ability to As (V). Overall consideration of the adsorption ability and the feasibility of polluted water management, iron oxides treated by high temperature carbonization were better than that of direct obtaining.

This study used maize (Zea mays L.) as the experimental material, which was the typical crop in purple soil area, investigated the effects of varied fertilizer application levels, including no fertilizer, traditional fertilizer amount (CK, 750 kg/hm2), and 0.5, 1.5, 2.0 and 2.5 times of the traditional fertilizer amount, on crop yields, growth characteristics and NP loss in leaching solution and runoff by plot experiments in slop field cropland and indoor analysis. Based on experiments on NP in relation to fertilization application rate, a unified economic indicator and evaluation model for the coordination effect of agronomic, water environmental and economic benefits were studied. The results showed that when the fertilizer application amount was 0-1870 kg/hm2, the leaf area index increased fast in the earlier stage and declined slowly in the later stage, plant height and yield increased with the increase of fertilizer application levels from CK to 2.0 times of traditional fertilizer level, but declined under the 2.5 times of traditional fertilizer level. The total N and total P concentration in runoff and leaching solution increased with the increase of fertilizer application levels. By the evaluation model, the effects of the marginal yield and the nutrient rich of maize fertilizer were calculated, the range of fertilization tolerance was 1154-1176 kg/hm2.

To investigate the effects of water parameters on the concentrations of heavy metals in water and fish muscle in recirculating aquaculture systems (RAS), using tilapia (Oreochromis niloticus) weighed (57.9±0.87) g as experimental creature, we conducted a 60-day experiment in 8 small RASs simulating the actual work condition with changing several water parameters including alkalinity, dissolved oxygen (DO) and total suspended solid (TSS). The results showed that at the end of the experiment, alkalinity had obvious effect on the content of Cu, Zn in water and content of Zn in muscles; dissolved oxygen had obvious effect on the content of Cu in water and contents of Cu, Zn in muscles; TSS had no significant effect on contents of heavy metals in both water and muscles. However, in such experimental conditions, the contents of heavy metals in the muscle (the edible part of fish) of tilapia were under the limits of the national and industrial standards.

The paper aims to summarize the research status of the genus Vallisneria, which has high value in water ecological restoration. By means of reviewing nearly 30 years relevant researches on Vallisneria biological characteristics, the interaction with environmental factors and the application situation in engineering etc., it was considered that cultivating the species of Vallisneria methodically with other aquatic plants could benefit the landscape construction, and could also be useful for water ecological restoration. Meanwhile, existing problems in researches on this genuswere pointed out in this paper. To achieving ecological restoration benefits, three issues were proposed for further study: (1) strengthening publicity and enlarging application; (2) standardizing plant maintenance and developing practical tools; (3) utilizing resources rationally and attaining sustainable development.

This study was designed to determine the effects of stocking density (0(D0), 40 ind/m3 (D1), 50 ind/m3 (D2), 60 ind/m3 (D3), 70 ind/m3 (D4)) on growth performance of yellow catfish (Pelteobagrus fulvidraco) and water quality in surrounding water of the enclosure ecosystem.The rearing trial lasted 24 days and the water quality was monitored every 3 days. At the end of the experiment, the growth performance of yellow catfish in each treatment were assessed to determine the optimum stocking density. The results showed that the final body weight,weight gain and specific growth rate of yellow catfish decreased with the increasing of stocking density, and the significant difference were found among group D1, D2 and D3 (P＜0.05). The condition factor in D1 and D2 was significantly bigger than it in D3 and D4 (P＜0.05). The nitrite nitrogen in surrounding water (p＜0.05) was significantly affected by the stocking density, and the levels of nitrite nitrogen increased with the increasing of stocking density. While the total nitrogen and nitrateSnitrogen were not affected by the stocking density (P＞0.05). During the first 18 days, the contents of ammonia nitrogen in all groups were stable at a low level and then increased significantly until the end of the experiment. Total phosphorus and phosphate showed were also not affected by the stocking density and their levels fluctuated within a certain range during the experiment period. Increase in stocking density would reduce the growth rate of yellow catfish and increase the harmful substances in surrounding water which could accelerate the deterioration of water quality.

To study the relationship between aquatic organisms and environmental indexes in the interlaced areas of agriculture and animal husbandry in Qinghai, diversity of benthic macroinvertebrates and physical and chemical indexes were investigated at 47 sampling sites in the upstream of Huangshui River in April (dry season) and August (rainy season) of 2015. In the sampling sites, water physical indexes of Huangshui River were determined by multiparameter water quality tester and FP311 bar-type flow meter. And water chemical indexes were tested in the laboratory. The contents of total nitrogen and total phosphorus were determined by ultraviolet spectrophotometry of potassium persulfate oxidation, the content of NH4 -N were determined by Nessler’s reagent spectrophotometry, and benthic macroinvertebrates were collected by Sauber’s net and D-shaped net. The results showed that the physical and chemical indexes in the branch stream of Huangshui River were better than that of the trunk stream, especially the turbidity, proportion of fine sand, contents of NH4 -N, TN and TP. There were a total of 59 species of the macro-invertebrates in 57 genera, 28 families. Among them, 4444 individuals of 54 species were belonged to 7 orders of Insecta, accounting for 91.5% of all species and 76.4% of the total individuals. Individuals in Crustacean, Mollusca and Oligochaeta occupied 23.6% of the total individuals. The average number of total taxa of benthic macroinvertebrates in the branch stream of Huangshui River was 6.76, which was not far from that in the trunk stream (8.14); the average number of total taxa of EPT in the branch stream of Huangshui River was 3.36, which had not obvious difference compared with that of the trunk stream (2.48). However, the species number of the pollution-tolerant macroinvertebrates in the trunk stream was larger than that in the branch stream, and the species number of the pollution-sensitive macroinvertebrates in the branch stream was larger than that in the trunk stream. The results indicated that water quality in the branch stream of was better than that of the trunk stream, and the difference was caused by the heavier pollution in the trunk stream.

The paper aims to reveal the effect of cold air process on temperature of different aquatic water. The response and variation of water temperature of each water layer caused by cold air process were studied based on water temperature data of two different water bodies during the occurrence of cold air in spring and autumn in 2011 and 2012, by using statistical analysis method. Besides, the water temperature reduction prediction models of each water layer were also established. The results showed that: (1) after the cold air, the amplitude reduction of water temperature of shallow layer was larger than that of deep one, and the minimum water temperature of large water body appeared obviously later than that of small water body; (2) the greater the intensity of cold air process, the greater the difference of water temperature reduction was, temperature of small water body was more likely to decrease under cold air; (3) the correlation between small water body’s temperature reduction and meteorological elements was much better than that of larger water body’s; and shallow water layer’s temperature was more vulnerable to the change of external meteorological elements, while the effect on deep layer was relatively inconspicuous, especially in deep layer of large water body; (4) the simulation result of established water temperature reduction model of small water body was much better, and the result was relatively good in the shallow layers (10 to 50 cm water layer) of large water body, while less satisfied in the deep layers (100 to 150 cm water layer). Thus, the predictive model established based on related meteorological factors can provide production guidance and warning during the critical aquaculture period in spring and autumn.

In order to optimize the design parameters of parabolic screen filter, a serial of experiments were developed under different conditions, such as screen size, inclination angle and water treatment. Removal rate of solid particles was considered as the evaluation indicator of the performance of parabolic screen filter. Screen size was set from 0.10 to 0.25 mm, inclination angle was set to be 37° and 53°, and influent water flow rate was set from 10 to 20 m3/h. Results showed that the particle removal rate had a certain correlation with screen size, it decreased with the increase of screen size. So the screen size was suggested to be equal to or less than mean diameter of solid particles. On the other hand, the removal rate had a negative correlation with influent water flow rate. The optimum hydraulic loading rate should be controlled lower than 50 m3/(m2?h). At last, larger inclination angle in appropriate range would be benefit for the enhancement of solid particle removal. In a word, parabolic screen filter is advisable and suitable for solid particle removal in aquaculture water treatment.

In order to understand the impact of macroscopic algae aquaculture on the content of seawater dissolved inorganic carbon (DIC), and clarify the change process of DIC content in different conditions (light, dark, alternation of light and dark), Sargassum thunbergii and Hizikia fusiforme collected from Wenzhou Dongtou offshore were cultivated in laboratory, three treatments (light, dark, alternation of light and dark) were set in the experiment, DIC contents were measured and DIC change rates were analyzed. The results showed that: DIC consumption rate of Sargassum thunbergii was higher than that of Hizikia fusiforme under light condition. DIC release rate of Sargassum thunbergii was higher than that of Hizikia fusiforme under dark condition. DIC consumption rate of both Sargassum thunbergii and Hizikia fusiforme increased at first and then reduced under the light and dark alternation condition, and DIC consumption rate of Sargassum thunbergii was higher than that of Hizikia fusiforme. With the carrying out of the light and dark alternated process, photosynthetic consumed DIC and dark respiration released DIC converted continuously. Overall, the aquaculture of macroscopic algae decreased the DIC content of seawater and promoted the atmospheric CO₂ transfer to seawater. With the harvest of macroscopic algae, a “removable carbon sink” was formed. The development of macroscopic algae aquaculture had important carbon sink ecological significance.

The purifying effect of aquatic plant configuration is more significant than that of single plant. The author discussed the purification mechanism of aquatic plants, as well as the purifying effects of different configurations on different waste water in moderate temperature season and low temperature season. The author put forward the problems that should be focused on in aquatic plants sewage purification application, and made research prospects from variety screening, cultivating and establishment, efficient annual purification model and so on.

The authors had a field trip to wetlands of Wu River in Linyi, Shandong Province, collected samples to determine and analyze water quality indexes, such as N, P, COD and BOD. The experimental results showed that the constructed wetlands could remove 55% of TN, 76% of COD and 70% of BOD, but only had a low removal rate of P. The average concentration of TN and TP of eight sample points were 26.55 and 0.125 mg/L, respectively. According to the standard of eutrophication degree analysis (Thomas), the TP and TN of Wu River wetlands are in the rich degree of eutrophication level. Therefore, the eutrophication degree of constructed wetlands of Wu River is high overall, indicating that wastewater treatment does not develop well.

In order to understand the impact of macroscopic algae farming on seawater DO content, to clear the change process of DO content, in light, dark, light and dark alternately conditions, Sargassum thunbergii and Hizikia fusiforme from Wenzhou Dongtou offshore were brought to the laboratory for breeding. Set light (2h, 6h, 12h), dark (2h, 6h, 12h), alternating light and dark (1h 1h, 6h 6h, 12h 12h) treatment conditions, DO was determined, also to analyzed its oxygen production rate and oxygen consumption rate. The result showed that: with the extension of farming time, Sargassum thunbergii and Hizikia fusiforme oxygen production rates were all declining, Sargassum thunbergii oxygen production rate was higher than Hizikia fusiforme (P<0.05); Under dark conditions, Sargassum thunbergii maximum oxygen consumption rate at the time of 6h up to 288.02mg/kgDW?h, Hizikia fusiforme maximum oxygen consumption rate at the time of 2h up to 207.46 mg / kgDW?h, Sargassum thunbergii oxygen consumption rate was higher than Hizikia fusiforme; Sargassum thunbergii net oxygen production rate under alternating light and dark increased slowly at first and then drastically reduced, the net oxygen production rate up to 457.08 mg / kgDW?h at the short alternating cycle (1h 1h). Hizikia fusiforme net oxygen production rate first increased and then decreased, while the medium alternating cycle (6h 6h) up to 64.04 mg / kgDW?h. Macroscopic algae farming with alternating light and dark environment when carried out, photosynthetic oxygen production and dark respiration oxygen consumption converted continuously. Overall, Macroscopic algae farming increased the DO content of the seawater. Ecological and social value of the macroscopic algae farming was significantly, it should be vigorously promoted.

Investigation on dynamics of Chl a concentration and water environment of four intensive fishponds, which cultured Oxyeleotris marmoratus, Ctenopharyngodon idellus, Micropterus salmoides and Channa argus, were carried out between May 2012 and December 2012 in Pearl River Delta. Variance analysis and Multiple Comparison (LSD) were used to study the difference of the water parameters of the fishponds, and stepwise multiple regression was used to analyze the relationships between Chl a and environmental factors in the investigating ponds, while the Self-Organizing Map (SOM) analysis was used to explore the water quality conditions. Results showed that TN, TP and Chemical Oxygen Demand (COD_Mn) of the ponds were varied from 1.52~22.76 mg/L, 0.20~4.82 mg/L and 3.71~50.76 mg/L, respectively, which indicated the water were overloaded by nutrients and organic contamination. There was significant difference on Chl a concentration (P<0.05) among the four kinds of fish ponds. Ctenopharyngodon idellus ponds had the highest Chl a concentration (mean value), followed by the Channa argus ponds and the Micropterus salmoides ponds, and the lowest was Oxyeleotris marmoratus ponds. Besides, the relationships between Chl a and environmental factors were different in each sampling ponds. Water environment parameters, such as salinity, conductivity, Total Dissolved Solids (TDS), COD_Mn, TN, TP, NO₃^--N, PO₄^3--P in Channa argus ponds were obviously higher (P<0.05) than other kinds. Based on SOM analysis, five clustering groups on water quality of all sampled ponds were found according to spatio-temporal patterns, and the water environment quality changed worse from Oxyeleotris marmoratus, Micropterus salmoides, Ctenopharyngodon idellus to Channa argus ponds.

Water environment with high density of fish feeding was simulated under Biotron Open Type and natural condition in Jingzhou of Jianghan Plain, and day-night aquaculture water observation of DO (dissolved oxygen) and water temperature variation were carried out by using water quality multi-parameter monitoring system in a totally open way. Dynamic balance formula was used to calculate water-atmosphere DO rate, oxygen production of photosynthesis, oxygen consuming rate of grass carp and water body; grass carp survival time under low oxygen condition was also observed. The result shows that, oxygen consuming rate of water body in pool is 1.22-1.83 mg/(L·h), while oxygen consuming rate of grass carp is 78.6-210.0 mg/(L·h) when water body DO is above 1.5 mg/L. The oxygen consuming rate of aquaculture ponds in high density fish feeding environment is more than 4 times of the oxygen consuming rate of fish. The oxygen dissolution rate of water-atmosphere interface is low. And oxygen production of photosynthesis is 3.47-4.33 mg/(L·h) in rainy or cloudy days, which is more than the total oxygen consuming rate of fish and aquaculture ponds, while oxygen production of photosynthesis in rainy days cannot maintain favorable environment in aquaculture ponds. The grass carp would gasping for air but still survive 5 more days in low DO environment as 0.1-0.4 mg/L. The result also indicates that lacking oxygen could cause the increase of H₂S and CH₄ in the bottom of aquaculture ponds; water convection in aquaculture ponds and increase of toxic substances caused by rain is the main reason of suffocation.

Combined with tobacco industry Dali Xiangyun water project of construction and management experience, according to the tobacco industry in Yunnan Province water project funded by the planning and construction of the discussion is being put into practice in Honghe Shiping defrosts water project construction supervision measures, the key is how to strengthen the supervision and management of the project puts forward some suggestions, in order to promote and safeguard the construction of the project management.

In order to investigate the changing characteristics of concentrations for typical anions (Cl^-, NO^3-, and SO₄^2- ) along with the variation of time and water level in water bodies of the Three Gorges Reservoir, Fuling, Shibaozhai in Zhongxian, which are located in the main stream of Yangtze River, and Hanfeng Lake, which is located in the Branch of Yangtze River, were selected as study sites. During the whole year, sections were set in investigate spots for stratified water sampling, and Cl^-、NO^3- and SO₄^2- in water samples were continuously monitored by an Ion chromatography once every two months, with the causes of there change being preliminary analyzed. The results showed that the whole year in research area, ion concentration of SO₄^2-, Cl^- and NO^3- were 14.67±1.71 mg/L, 10.66±4.88 mg/L and 1.89±0.15 mg/L respectively, and they all displayed significant variations along with seasonal change, with a coefficient variation larger than 43%. Meanwhile, the change of water levels at the dam’s reservoir had great influence on the content of anions in main stream. Variations of anion concentration in different sampling sites between Fuling, Zhongxian and Kaixian were quite different, with a coefficient variation larger than 40%. The total ionic concentration of reservoir area in spring, an average of 13.02 mg/L, was much higher than that in other seasons.

In order to achieve sustainable management of water resources conservation forest in the Qilian Mountain, improve the unreasonable forest structure and increase function of the ecosystem. On the basis of field investigation, using the method of ecology, the author analyzed the problems existing in the Qilian Mountain water conservation forests ecological restoration and protection, such as stand density, low quality, divided, poor natural regeneration, plant diseases and insect pests and management system and so on. Countermeasures were proposed. In order to increase the productivity of Qilian Mountain water conservation forests ecosystem and self-sustaining capacity and environmental capacity, the author suggested that strengthen the function of the ecological environment, safeguard the sustainable development and social economy of Qilian Mountain and Hexi Corridor. People should establish a long-term protection mechanism, carry out the artificial afforestation, scientific management, strengthen vegetation restoration technology research and promotion.

Forest water conservation is an important indicator of the state of the forest ecological function, the estimation of the volume can be a very effective way of understanding the ecological value of forest resources, and the data support for the determination of management strategy for the forest resources. The author chose Liuhe County in Jilin Province as the study area, and extracted relevant factors to establish the model of remote sensing estimation of forest water conservation volume in Liuhe County based on Landsat-5 TM remote sensing image data. It showed that: the prediction accuracy of the model was 79.24%, after precision test. From the distribution map of the forest growing stock of Liuhe, as a result of the inversion of the model, it showed that the forest stock volume was 4.62×10⁶ m³. The distribution of forest water conservation quantity Liuhe Country was formed for analysis of the relationship between ability of water conservation forest in space and spatial elements.