Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on...Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on an egg duck farm, and water hyacinth （Eichhornia crassipes） was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks＇ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand （COD）, 21.78% of total nitrogen （TN） and 23.02% of total phosphorus （TP）. Both dissolved oxygen （DO） and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the differences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group （P 〈 0.05）, but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth. We concluded that a water hyacinth system was effective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.展开更多
From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was ...From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was to evaluate the growth rate of invasive aquatic macrophytes and their contribution to the use of organic fertilisers: a case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon) with a view to its appropriate use in agronomy. The specific objective was to examine the impact of anthropogenic actions on Lobé Creek, characterise physico-chemical environment of the study area, and evaluate the growth rate of E. crassipes and its chemical composition with a view to producing an organic biofertiliser. The results show that E. crassipes represents a considerable threat to the populations of these localities. As for the physico-chemical parameters, the temperature values vary from 24 ± 1.41˚C to 26.5 ± 1.13˚C;pH from 6.3 ± 0.1 to 7.2 ± 0.07;conductivity and dissolved oxygen vary respectively from 40.7 ± 1.83 µS/cm to 19.6 ± 3.11 µS/cm and from 7.3 ± 0.14 mg/l to 5.8 ± 1.55 mg/l. Its average growth rate varies from 0.69 feet/day to 0.63 feet/day. With regard to the nitrogen, phosphorus and potassium content of water hyacinth plants, the results show that the average total nitrogen content ranges from 6.11 ± 1.59 g/kg to 5.2 ± 2.03 g/kg;total phosphorus, from 0.52 ± 0.54 g/kg to 0.88 ± 0.38 g/kg;and potassium, from 1.43 ± 0.45 g/kg to 2.61 ± 0.89 g/kg.展开更多
Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get ins...Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get insight into different mechanisms involved in nitrogen removal. Methods: The aquatic macrophytes used include Eichhornia crassipes (sum-mer-autumn floating macrophyte), Elodea nuttallii (winter-growing submerged macrophyte), and nitrogen cycling bacteria in-cluding ammonifying, nitrosating, nitrifying and denitrifying bacteria isolated from Taihu Lake. The immobilization carriers materials were made from hydrophilic monomers 2-hydroxyethyl acrylate (HEA) and hydrophobic 2-hydroxyethyl methylacrylate (HEMA). Two experiments were conducted to evaluate the roles of macrophytes combined with INCB on nitrogen removal from eutrophic water during different seasons. Results: Eichhornia crassipes and Elodea nuttallii had different potentials in purification of eutrophic water. Floating macrophyte+bacteria (INCB) performed best in improving water quality (during the first experiment) and decreased total nitrogen (TN) by 70.2%, nitrite and ammonium by 92.2% and 50.9%, respectively, during the experimental period, when water transparency increased from 0.5 m to 1.8 m. When INCB was inoculated into the floating macrophyte system, the populations of nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 2 orders of magnitude compared to the un-inoculated treatments, but ammonifying bacteria showed no obvious difference between different treatments. Lower values of chlorophyll a, CODMn, and pH were found in the microbial-plant integrated system, as compared to the control. Highest reduction in N was noted during the treatment with submerged macrophyte+INCB, being 26.1% for TN, 85.2% for nitrite, and 85.2% for ammonium at the end of 2nd experiment. And in the treatment, the populations of ammonifying, nitrosating, nitrifying, and de-nitrifying bacteria increased by 1 to 3 orders of magnitude, as compared 展开更多
Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth gl...Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth globally at different levels and environmental sustainability, biological control against water hyacinth seems to have overlooked the socio-economic sustainability in assisting the ravaged communities, gain resilience and adapt to the challenges of the invasive alien species. This manuscript evaluates the potential to draw out more from biological control of the water hyacinth by evaluating the potential to utilize Neochetina eichhorniae and Neochetina bruchi as feed. The live insects of the two species were collected from the water hyacinth marts in the nearby L. Victoria in Siaya county, Kenya. Where they were then transferred for semi-cultivation in localized ponds for reproduction and closer monitoring. The ponds having been set up in completely randomized design while in the open within the same climatic region mimicked the water quality and most abiotic conditions of the lake necessary for the insects’ and host plant acclimatization and reproduction. The samples for proximate analysis were collected from these ponds as per the research and experimental design. The chemical compositions of the Neochetina bruchi, N. eichhorniae and their larvae composite, satisfactorily compared to basic fish feed requirements, specifically as a protein source having crude protein (CP) percentage per DM of 55.0350 ± 0.025, 54.4350 ± 0.035 and 62.2750 ± 0.025 respectively.展开更多
Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy...Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7～50 μm), reduced vascular tissue and absorbing structures. Textile waste significantly affected the size of root cells.The presence of raphide crystals was noted in parenchyma cells of various organs in treated plants.展开更多
This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(D...This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.展开更多
Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic.Biochar prepared from plants is commonly used to ...Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic.Biochar prepared from plants is commonly used to remediate soils and sequester carbon.Here, the catalytic activity of biochar prepared from plants enriched with iron was investigated as a potentially beneficial use of metal-contaminated plants.In a 30-day hydroponic experiment, E.crassipes was exposed to different concentrations of Fe(Ⅲ)(0, 4, 8, 16, 32 and 64 mg/L), and Fe-biochar(Fe-BC) was prepared by pyrolysis of the plant roots.The biochar was characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive X-ray spectrometry(EDS), Brunauer–Emmett–Teller(BET) analysis, X-ray photoelectron spectroscopy(XPS) and atomic absorption spectrometry(AAS).The original root morphology was visible and iron was present as γ-Fe2O3 and Fe3O4.The biochar enriched with Fe(Ⅲ) at 8 mg/L(8-Fe-BC) had the smallest specific surface area(SSA, 13.54 m^2/g) and the highest Fe content(27.9 mg/g).Fe-BC catalytic activity was tested in the electrocatalytic reduction of H2O2 using cyclic voltammetry(CV).The largest reduction current(1.82 mA/cm^2) was displayed by 8-Fe-BC, indicating the highest potential catalytic activity.We report here, for the first time, on the catalytic activity of biochar made from iron-enriched plants and demonstrate the potential for reusing metalcontaminated plants to produce a biochar catalyst.展开更多
At present, sensitive material factories and various cinefilm processing factories can only treat silver-containing waste water of high concentration, and have difficulties in dealing with the waste water of silver co...At present, sensitive material factories and various cinefilm processing factories can only treat silver-containing waste water of high concentration, and have difficulties in dealing with the waste water of silver concentration lower than 2-3 mg/1. Therefore the loss of silver is relatively large. This not only leads to a great economic loss, but also brings about seri-展开更多
The aim of this study was to evaluate the herbicide glyphosate under aquatic environment conditions, in a controlled and closed experimental field, in the management of water hyacinth (Eichhornia crassipes) in reservo...The aim of this study was to evaluate the herbicide glyphosate under aquatic environment conditions, in a controlled and closed experimental field, in the management of water hyacinth (Eichhornia crassipes) in reservoirs. Twenty reservoirs (polyethylene water tanks) with storage capacity of 1000 liters were used, without water flow and without evapotranspired water replacement (worst case), being 04 for each treatment. The adult plants were placed in the water tanks to provide 90% surface occupation of the reservoir. Five treatments with four repetitions were considered, being: 1) Reservoir colonized by water hyacinth without control;2) Reservoir colonized by water hyacinth, controlled by glyphosate;3) Reservoir colonized by water hyacinth, controlled by freezing;4) Reservoir without water hyacinth and glyphosate application and 5) Reservoir without water hyacinth and no glyphosate application. The glyphosate herbicide was used at the highest recommended dose, 7.0 L·ha-1 or 3360 g of acid equivalent per ha, applied using carbon dioxide precision equipment (backpack sprayer), providing a flow rate of 200 L·ha-1. The water samples were collected at the time of application, 6, 12, 18 and 24 hours after application and also at 2, 4, 8, 16, 32 and 64 days after application, in the morning, always at the same time, also between 8 and 9 h. The method used for determination of residues was by high performance liquid chromatography (HPLC) and mass spectrometry with a mass selective detector. Low concentrations of glyphosate and aminomethylphosphonic acid (AMPA) were found in both reservoirs that received application of the product. The half-life of glyphosate in water to the reservoirs with water hyacinth was 11 days and in the reservoirs without water hyacinth was 21 days. The results show a low potential of environmental impact of glyphosate use in the control of water hyacinth in reservoirs.展开更多
Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and w...Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。展开更多
6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which w...6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which was synthesized from stigmasterol 2.展开更多
The present study had the purpose to assess the behavior of the herbicide glyphosate in the control of water hyacinths, in a water environment through half-life, in a controlled and closed experimental field, in order...The present study had the purpose to assess the behavior of the herbicide glyphosate in the control of water hyacinths, in a water environment through half-life, in a controlled and closed experimental field, in order to contribute to the analysis of the risk of the environmental impact of the use of this product. Eight fiber-cement tanks with the storage capacity of 250 liters were used under the conditions without water flow and without replacement of water. The experiment was designed in two treatments with four repetitions, the first being colonized by water hyacinths and the second without the presence of the macrophyte. The recommended dose, according to the manufacturer, was 7.0 L·ha-1 or 3402 g·ha-1 of equivalent acid. For the application in the tanks, we have used carbon dioxide (CO2) precision equipment, providing a flow rate of 200 L·ha-1. The samples were collected on the day of the application (day zero) and 2, 4, 8, 16, 32 and 64 days thereafter (DAP). The method used for determination of residues was by high performance liquid chromatography (HPLC) and mass spectrometry with a mass selective detector. From the mathematical model of charge decay, the half-life of glyphosate in water was estimated to six days for the tanks without water hyacinths and sixteen days for the tanks colonized by macrophytes. The result obtained permits to conclude that the glyphosate in water is quickly degraded in closed water environments and does not leave residues that would prevent its use.展开更多
This dissertation chiefly examines the functions of water hyacinth and discusses the potential problems associated with invasive species.In general,E.crassipes has significant potential as a source of biomass energy,s...This dissertation chiefly examines the functions of water hyacinth and discusses the potential problems associated with invasive species.In general,E.crassipes has significant potential as a source of biomass energy,such as improving physical properties of soil as well as soil structure;additionally,ventilates the soil and brings great conveniences for water penetrating through soil.With regard to the overall research,an amount of significant research has illustrated that water hyacinth can form dense mats that spread out across water surfaces in the end blocking the entire water body.Specifically,water hyacinth would change water clarity and lessening phytoplankton production,dissolved oxygen,nitrogen,phosphorous,heavy metals and concentrations of other pollutants.Relevant studies quoted in this report would gain prominence in further aquatic conservation and maintaining the integrity of ecosystem function since previous research and experience would be highlighted and explored in depth.Although some gaps between theory and experimental evidence still exist,preferable management method combines chemical,mechanical,fire and biological control methods with land management changes.展开更多
[Objective] The aim was to study the effects of Eichhornia crassipes as an invasive plant on aquatic plants in Dianchi Lake. [Method] Based on the determination of chlorophyll content of phytoplankton and submerged pl...[Objective] The aim was to study the effects of Eichhornia crassipes as an invasive plant on aquatic plants in Dianchi Lake. [Method] Based on the determination of chlorophyll content of phytoplankton and submerged plant (Potamogeton pectinatus) in Dianchi Lake in different months, the effects of E. crassipes on aquatic plants in Dianchi Lake were studied, and the allelopathy effect of root culture solution of E. crassipes on Microcystis aquaticum was discussed. [Result] The growth of E. crassipes in Dianchi Lake reduced the chlorophyll content of phytoplankton and submerged plant (P. pectinatus), and it showed that E. crassipes had certain inhibitory effect on their growth; the culture solution of E. crassipes root inhibited M. aeruginosa growth obviously. [Conclusion] The study could provide scientific references for the prevention and control of ecological safety of E. crassipes.展开更多
对水葫芦采用不同浓度的NaOH预处理,研究其对水葫芦厌氧发酵产气量的影响. 在培养基中分别加入乙酸钠、碳酸氢钠和发酵上清液培养沙角衣藻,讨论对沙角衣藻生长的影响. 结果发现,2% 浓度的NaOH预处理对根发酵产气最为有利,根叶混合物经...对水葫芦采用不同浓度的NaOH预处理,研究其对水葫芦厌氧发酵产气量的影响. 在培养基中分别加入乙酸钠、碳酸氢钠和发酵上清液培养沙角衣藻,讨论对沙角衣藻生长的影响. 结果发现,2% 浓度的NaOH预处理对根发酵产气最为有利,根叶混合物经预处理后可获得802.6 mL/100 g新鲜底物的最佳产气量;以乙酸钠作培养基碳源,沙角衣藻生物量能得到明显积累,可从初始的0.4×10~6个/mL达到10 d后的2.84×10~6个/mL.Abstract：Eichhornia crassipes Solms was pretreated with different concentration of NaOH to study the influence of pretreation on gas production volume. CH_3COONa、NaHCO_3 and supernatant of anaerobic fermentation of Eichhornia crassipes Solms liquor were separately added into culture medium of Chlamydomonas sajiao Lewin to study the effect of carbon source on the growth of algae. The 2% concentration was the best pretreation concentration for gas production, and each 100 g fresh substrate of the mixture (of roots and leaves) produced 802.6 mL biogas. And CH_3COONa obviously promoted the growth of Chlamydomonas sajiao Lewin, the biomass varied from the initial 0.4×10~6 algae per milliliter to the final 2.84×10~6 algae per milliliter.展开更多
The effects of free-floating mats of the water hyacinth Eichhornia crassipes (Mart.) Solms on the limnological characteristics of two lakes located on the fringing floodplain of the lower Paraná River (27°27...The effects of free-floating mats of the water hyacinth Eichhornia crassipes (Mart.) Solms on the limnological characteristics of two lakes located on the fringing floodplain of the lower Paraná River (27°27'S, 58°55'W) were studied monthly between April 1998 and April 1999. The mobility of the free-floating vegetation at both locations prevented continual observation. Therefore, to carry out the intensive sampling needed for this study, two experimental ponds (A and B) were filled with water from the Paraná River in 1996. Pond A was designed to reproduce conditions similar to those of lakes vegetated with water hyacinth. Pond B was designed to recreate the limnological conditions of these lakes, such as a high concentration of dissolved and fine particulate organic matter and a peat layer on the bottom;however, pond B lacked macrophytes. Natural lakes covered with free-floating vegetation were very similar to pond A, but these water bodies showed a lower temperature, dissolved oxygen level and pH and a higher conductivity than the non-vegetated pond. Our results indicated that water hyacinth has a strong local influence on the limnological conditions in subtropical shallow lakes. Our results may assist in developing cause-consequence models by demonstrating the relevance of the effect of thermal damping produced by floating meadows.展开更多
Removal of Methylene Blue (MB) and Crystal Violet (CV) dyes from monocomponent and binary aqueous solutions by water hyacinth-E. Crassipes roots fixed on alginate (a low-cost adsorbent) has been investigated. The exte...Removal of Methylene Blue (MB) and Crystal Violet (CV) dyes from monocomponent and binary aqueous solutions by water hyacinth-E. Crassipes roots fixed on alginate (a low-cost adsorbent) has been investigated. The extent of adsorption was evaluated as a function of solution pH, initial dye concentration, and bead biomass loading. Kinetic sorption data were analysed by widely used models: pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The results showed that pseudo-second-order model better described the biosorption experimental data than the pseudo-first-order kinetic model for both dyes, whilst the Elovich model fitted the biosorption experimental data at lower dye concentrations. The intraparticle diffusion model indicated that sorption of CV and MB was characterized by rapid surface adsorption coupled with slow film diffusion process at higher initial dye concentration and at all initial bead biomass loading. The range of mean free energy values confirmed physical adsorption as the mechanism for dye removal from solution.展开更多
文摘Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on an egg duck farm, and water hyacinth （Eichhornia crassipes） was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks＇ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand （COD）, 21.78% of total nitrogen （TN） and 23.02% of total phosphorus （TP）. Both dissolved oxygen （DO） and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the differences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group （P 〈 0.05）, but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth. We concluded that a water hyacinth system was effective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.
文摘From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was to evaluate the growth rate of invasive aquatic macrophytes and their contribution to the use of organic fertilisers: a case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon) with a view to its appropriate use in agronomy. The specific objective was to examine the impact of anthropogenic actions on Lobé Creek, characterise physico-chemical environment of the study area, and evaluate the growth rate of E. crassipes and its chemical composition with a view to producing an organic biofertiliser. The results show that E. crassipes represents a considerable threat to the populations of these localities. As for the physico-chemical parameters, the temperature values vary from 24 ± 1.41˚C to 26.5 ± 1.13˚C;pH from 6.3 ± 0.1 to 7.2 ± 0.07;conductivity and dissolved oxygen vary respectively from 40.7 ± 1.83 µS/cm to 19.6 ± 3.11 µS/cm and from 7.3 ± 0.14 mg/l to 5.8 ± 1.55 mg/l. Its average growth rate varies from 0.69 feet/day to 0.63 feet/day. With regard to the nitrogen, phosphorus and potassium content of water hyacinth plants, the results show that the average total nitrogen content ranges from 6.11 ± 1.59 g/kg to 5.2 ± 2.03 g/kg;total phosphorus, from 0.52 ± 0.54 g/kg to 0.88 ± 0.38 g/kg;and potassium, from 1.43 ± 0.45 g/kg to 2.61 ± 0.89 g/kg.
基金Project supported by the Ministry of Science and Technology of China, the Education Ministry of China (No. 20305), Australia Gov-ernment’s Innovation Statement Backing Australia’s Ability (No. [2002]68), and the Science and Technology Bureau of ZhejiangProvince (No. 2005C22020), China
文摘Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get insight into different mechanisms involved in nitrogen removal. Methods: The aquatic macrophytes used include Eichhornia crassipes (sum-mer-autumn floating macrophyte), Elodea nuttallii (winter-growing submerged macrophyte), and nitrogen cycling bacteria in-cluding ammonifying, nitrosating, nitrifying and denitrifying bacteria isolated from Taihu Lake. The immobilization carriers materials were made from hydrophilic monomers 2-hydroxyethyl acrylate (HEA) and hydrophobic 2-hydroxyethyl methylacrylate (HEMA). Two experiments were conducted to evaluate the roles of macrophytes combined with INCB on nitrogen removal from eutrophic water during different seasons. Results: Eichhornia crassipes and Elodea nuttallii had different potentials in purification of eutrophic water. Floating macrophyte+bacteria (INCB) performed best in improving water quality (during the first experiment) and decreased total nitrogen (TN) by 70.2%, nitrite and ammonium by 92.2% and 50.9%, respectively, during the experimental period, when water transparency increased from 0.5 m to 1.8 m. When INCB was inoculated into the floating macrophyte system, the populations of nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 2 orders of magnitude compared to the un-inoculated treatments, but ammonifying bacteria showed no obvious difference between different treatments. Lower values of chlorophyll a, CODMn, and pH were found in the microbial-plant integrated system, as compared to the control. Highest reduction in N was noted during the treatment with submerged macrophyte+INCB, being 26.1% for TN, 85.2% for nitrite, and 85.2% for ammonium at the end of 2nd experiment. And in the treatment, the populations of ammonifying, nitrosating, nitrifying, and de-nitrifying bacteria increased by 1 to 3 orders of magnitude, as compared
文摘Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth globally at different levels and environmental sustainability, biological control against water hyacinth seems to have overlooked the socio-economic sustainability in assisting the ravaged communities, gain resilience and adapt to the challenges of the invasive alien species. This manuscript evaluates the potential to draw out more from biological control of the water hyacinth by evaluating the potential to utilize Neochetina eichhorniae and Neochetina bruchi as feed. The live insects of the two species were collected from the water hyacinth marts in the nearby L. Victoria in Siaya county, Kenya. Where they were then transferred for semi-cultivation in localized ponds for reproduction and closer monitoring. The ponds having been set up in completely randomized design while in the open within the same climatic region mimicked the water quality and most abiotic conditions of the lake necessary for the insects’ and host plant acclimatization and reproduction. The samples for proximate analysis were collected from these ponds as per the research and experimental design. The chemical compositions of the Neochetina bruchi, N. eichhorniae and their larvae composite, satisfactorily compared to basic fish feed requirements, specifically as a protein source having crude protein (CP) percentage per DM of 55.0350 ± 0.025, 54.4350 ± 0.035 and 62.2750 ± 0.025 respectively.
基金Project (No. 30070017) supported by the National Natural Science Foundation of China
文摘Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7～50 μm), reduced vascular tissue and absorbing structures. Textile waste significantly affected the size of root cells.The presence of raphide crystals was noted in parenchyma cells of various organs in treated plants.
文摘This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.
基金supported by supported by the National Natural Science Foundation of China (Nos.21677086 and 21577078)Hubei Innovation Group Project (No.2015CFA021)+1 种基金the Hubei Foreign Science and Technology Cooperation Project (No.2018AHB020)Three Gorges University Master’s Thesis Training Fund (No.2018SSPY143).
文摘Eichhornia crassipes is a hyperaccumulator of metals and has been widely used to remove metal pollutants from water, but disposal of contaminated plants is problematic.Biochar prepared from plants is commonly used to remediate soils and sequester carbon.Here, the catalytic activity of biochar prepared from plants enriched with iron was investigated as a potentially beneficial use of metal-contaminated plants.In a 30-day hydroponic experiment, E.crassipes was exposed to different concentrations of Fe(Ⅲ)(0, 4, 8, 16, 32 and 64 mg/L), and Fe-biochar(Fe-BC) was prepared by pyrolysis of the plant roots.The biochar was characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive X-ray spectrometry(EDS), Brunauer–Emmett–Teller(BET) analysis, X-ray photoelectron spectroscopy(XPS) and atomic absorption spectrometry(AAS).The original root morphology was visible and iron was present as γ-Fe2O3 and Fe3O4.The biochar enriched with Fe(Ⅲ) at 8 mg/L(8-Fe-BC) had the smallest specific surface area(SSA, 13.54 m^2/g) and the highest Fe content(27.9 mg/g).Fe-BC catalytic activity was tested in the electrocatalytic reduction of H2O2 using cyclic voltammetry(CV).The largest reduction current(1.82 mA/cm^2) was displayed by 8-Fe-BC, indicating the highest potential catalytic activity.We report here, for the first time, on the catalytic activity of biochar made from iron-enriched plants and demonstrate the potential for reusing metalcontaminated plants to produce a biochar catalyst.
基金Project supported by the National Natural Science Foundation of China
文摘At present, sensitive material factories and various cinefilm processing factories can only treat silver-containing waste water of high concentration, and have difficulties in dealing with the waste water of silver concentration lower than 2-3 mg/1. Therefore the loss of silver is relatively large. This not only leads to a great economic loss, but also brings about seri-
文摘The aim of this study was to evaluate the herbicide glyphosate under aquatic environment conditions, in a controlled and closed experimental field, in the management of water hyacinth (Eichhornia crassipes) in reservoirs. Twenty reservoirs (polyethylene water tanks) with storage capacity of 1000 liters were used, without water flow and without evapotranspired water replacement (worst case), being 04 for each treatment. The adult plants were placed in the water tanks to provide 90% surface occupation of the reservoir. Five treatments with four repetitions were considered, being: 1) Reservoir colonized by water hyacinth without control;2) Reservoir colonized by water hyacinth, controlled by glyphosate;3) Reservoir colonized by water hyacinth, controlled by freezing;4) Reservoir without water hyacinth and glyphosate application and 5) Reservoir without water hyacinth and no glyphosate application. The glyphosate herbicide was used at the highest recommended dose, 7.0 L·ha-1 or 3360 g of acid equivalent per ha, applied using carbon dioxide precision equipment (backpack sprayer), providing a flow rate of 200 L·ha-1. The water samples were collected at the time of application, 6, 12, 18 and 24 hours after application and also at 2, 4, 8, 16, 32 and 64 days after application, in the morning, always at the same time, also between 8 and 9 h. The method used for determination of residues was by high performance liquid chromatography (HPLC) and mass spectrometry with a mass selective detector. Low concentrations of glyphosate and aminomethylphosphonic acid (AMPA) were found in both reservoirs that received application of the product. The half-life of glyphosate in water to the reservoirs with water hyacinth was 11 days and in the reservoirs without water hyacinth was 21 days. The results show a low potential of environmental impact of glyphosate use in the control of water hyacinth in reservoirs.
基金This study was financially supported by the Natural Science Foundation of the Science and Technology Commission of Shanghai Municipality(Grant No.13ZR1427300)Spark Program of the state ministry of science and technology of China(2015GA680005).
文摘Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。
文摘6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which was synthesized from stigmasterol 2.
文摘The present study had the purpose to assess the behavior of the herbicide glyphosate in the control of water hyacinths, in a water environment through half-life, in a controlled and closed experimental field, in order to contribute to the analysis of the risk of the environmental impact of the use of this product. Eight fiber-cement tanks with the storage capacity of 250 liters were used under the conditions without water flow and without replacement of water. The experiment was designed in two treatments with four repetitions, the first being colonized by water hyacinths and the second without the presence of the macrophyte. The recommended dose, according to the manufacturer, was 7.0 L·ha-1 or 3402 g·ha-1 of equivalent acid. For the application in the tanks, we have used carbon dioxide (CO2) precision equipment, providing a flow rate of 200 L·ha-1. The samples were collected on the day of the application (day zero) and 2, 4, 8, 16, 32 and 64 days thereafter (DAP). The method used for determination of residues was by high performance liquid chromatography (HPLC) and mass spectrometry with a mass selective detector. From the mathematical model of charge decay, the half-life of glyphosate in water was estimated to six days for the tanks without water hyacinths and sixteen days for the tanks colonized by macrophytes. The result obtained permits to conclude that the glyphosate in water is quickly degraded in closed water environments and does not leave residues that would prevent its use.
文摘This dissertation chiefly examines the functions of water hyacinth and discusses the potential problems associated with invasive species.In general,E.crassipes has significant potential as a source of biomass energy,such as improving physical properties of soil as well as soil structure;additionally,ventilates the soil and brings great conveniences for water penetrating through soil.With regard to the overall research,an amount of significant research has illustrated that water hyacinth can form dense mats that spread out across water surfaces in the end blocking the entire water body.Specifically,water hyacinth would change water clarity and lessening phytoplankton production,dissolved oxygen,nitrogen,phosphorous,heavy metals and concentrations of other pollutants.Relevant studies quoted in this report would gain prominence in further aquatic conservation and maintaining the integrity of ecosystem function since previous research and experience would be highlighted and explored in depth.Although some gaps between theory and experimental evidence still exist,preferable management method combines chemical,mechanical,fire and biological control methods with land management changes.
基金Supported by Scientific Demonstration Engineering Project in Kunming City (109S010103)
文摘[Objective] The aim was to study the effects of Eichhornia crassipes as an invasive plant on aquatic plants in Dianchi Lake. [Method] Based on the determination of chlorophyll content of phytoplankton and submerged plant (Potamogeton pectinatus) in Dianchi Lake in different months, the effects of E. crassipes on aquatic plants in Dianchi Lake were studied, and the allelopathy effect of root culture solution of E. crassipes on Microcystis aquaticum was discussed. [Result] The growth of E. crassipes in Dianchi Lake reduced the chlorophyll content of phytoplankton and submerged plant (P. pectinatus), and it showed that E. crassipes had certain inhibitory effect on their growth; the culture solution of E. crassipes root inhibited M. aeruginosa growth obviously. [Conclusion] The study could provide scientific references for the prevention and control of ecological safety of E. crassipes.
文摘对水葫芦采用不同浓度的NaOH预处理,研究其对水葫芦厌氧发酵产气量的影响. 在培养基中分别加入乙酸钠、碳酸氢钠和发酵上清液培养沙角衣藻,讨论对沙角衣藻生长的影响. 结果发现,2% 浓度的NaOH预处理对根发酵产气最为有利,根叶混合物经预处理后可获得802.6 mL/100 g新鲜底物的最佳产气量;以乙酸钠作培养基碳源,沙角衣藻生物量能得到明显积累,可从初始的0.4×10~6个/mL达到10 d后的2.84×10~6个/mL.Abstract：Eichhornia crassipes Solms was pretreated with different concentration of NaOH to study the influence of pretreation on gas production volume. CH_3COONa、NaHCO_3 and supernatant of anaerobic fermentation of Eichhornia crassipes Solms liquor were separately added into culture medium of Chlamydomonas sajiao Lewin to study the effect of carbon source on the growth of algae. The 2% concentration was the best pretreation concentration for gas production, and each 100 g fresh substrate of the mixture (of roots and leaves) produced 802.6 mL biogas. And CH_3COONa obviously promoted the growth of Chlamydomonas sajiao Lewin, the biomass varied from the initial 0.4×10~6 algae per milliliter to the final 2.84×10~6 algae per milliliter.
文摘The effects of free-floating mats of the water hyacinth Eichhornia crassipes (Mart.) Solms on the limnological characteristics of two lakes located on the fringing floodplain of the lower Paraná River (27°27'S, 58°55'W) were studied monthly between April 1998 and April 1999. The mobility of the free-floating vegetation at both locations prevented continual observation. Therefore, to carry out the intensive sampling needed for this study, two experimental ponds (A and B) were filled with water from the Paraná River in 1996. Pond A was designed to reproduce conditions similar to those of lakes vegetated with water hyacinth. Pond B was designed to recreate the limnological conditions of these lakes, such as a high concentration of dissolved and fine particulate organic matter and a peat layer on the bottom;however, pond B lacked macrophytes. Natural lakes covered with free-floating vegetation were very similar to pond A, but these water bodies showed a lower temperature, dissolved oxygen level and pH and a higher conductivity than the non-vegetated pond. Our results indicated that water hyacinth has a strong local influence on the limnological conditions in subtropical shallow lakes. Our results may assist in developing cause-consequence models by demonstrating the relevance of the effect of thermal damping produced by floating meadows.
文摘Removal of Methylene Blue (MB) and Crystal Violet (CV) dyes from monocomponent and binary aqueous solutions by water hyacinth-E. Crassipes roots fixed on alginate (a low-cost adsorbent) has been investigated. The extent of adsorption was evaluated as a function of solution pH, initial dye concentration, and bead biomass loading. Kinetic sorption data were analysed by widely used models: pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The results showed that pseudo-second-order model better described the biosorption experimental data than the pseudo-first-order kinetic model for both dyes, whilst the Elovich model fitted the biosorption experimental data at lower dye concentrations. The intraparticle diffusion model indicated that sorption of CV and MB was characterized by rapid surface adsorption coupled with slow film diffusion process at higher initial dye concentration and at all initial bead biomass loading. The range of mean free energy values confirmed physical adsorption as the mechanism for dye removal from solution.
