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Assessment of heavy metal accumulation in freshwater fish of Dongting Lake,china:Effects of feeding habits,habitat preferences and body size

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Journal of Environmental Sciences 2022年第2期34卷 355-365页

作者： Xiaoming Jiang Jun Wang Baozhu Pan Dianbao Li Yuzhu Wang Xinyuan Liu State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi'an University of TechnologyXi'an 710048China

We measured the concentrations of Cr,Fe,Ni,Cu,Zn,Cd,Pb and Hg,and the stable isotope ratios(δ^(13)C and δ^(15)N)in 87 fish samples within 12 economic fish species collected from the Dongting Lake,the second largest freshwater lake in china.With few exceptions in concentration of Cr,most of fish species showed lower concentrations of the 8 metals than legislation thresholds.Piscivorous fishes had significantly higher values of δ^(15)N(possessing higher trophic level)and metal concentrations than planktivorous and herbivorous fishes.Moreover,demersal fishes showed higher concentrations of Cu,Zn,Cd and Pb than pelagic and benthopelagic fishes.We found positive correlations between concentrations of Fe,Pb and Hg and δ^(15)N ratio,confirming the biomagnification of the three metals through trophic transfer.In contrast,fishes showed clear growth dilution effect for Ni,Zn,Cu,Pb and Hg,indicated by the negative correlations between their concentrations and fish weight or length.Multiple regression analysis demonstrated that growth dilution and biomagnification effects simultaneously governed the metal concentrations in fish muscle,and the two effects'importance varied among different metals.The human health risk assessment indicated that all 8 metals gave target hazard quotient(THQ)values<1.0,i.e.,the estimated daily intake(EDI)of metals did not exceed the oral reference dose(Rf D),indicating a safe consumption of these fish species for consumer.Our study provides comprehensive approaches to better understand the determining processes and potential risk of heavy metals in freshwater lake fishes.

关键词： Heavy metals Stable isotope ratio Biomagnification Growth dilution Risk assessment Edible fishes

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Correlation analysis of cavitation-induced pressure pulsation and vibration in a bulb turbine

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Journal of Hydrodynamics 2023年第6期35卷 1052-1063页

作者： Tian-shu Li Jian-jun Feng Guo-jun Zhu Yun-zhe Li Xing-qi Luo state key laboratory of eco-hydraulics in northwest arid region xi’an University of Technologyxi’an710048China

Cavitation is one of the main causes of deteriorating stability of bulb turbines.To enhance their stability,this study examines the effects of runner cavitation on draft tube pressure fluctuation and vibration in bulb turbine through experimental methods.With varying cavitation coefficients,a synchronous test system,including a high-speed camera,vibration acceleration sensors and pressure pulsation sensors,is applied to obtain cavitation images of the runner,vibration and internal fluid pressure pulsation data of the draft tube.The results show that the correlated component of pressure pulsation signals during the cavitation process is the synchronous pressure pulsation of 16f_(n)With the development of cavitation,the amplitude of synchronous pressure pulsation increases first and then decreases.Cavitation enhances the high-frequency vibration on the wall of runner chamber.The root mean square(rms)of the vertical vibration component IMF3,the horizontal vibration components IMF2,IMF4 are linearly negatively correlated with the cavitation coefficient.The associated component between cavitation-induced vibration and pressure pulsation signal is 16f_(n)and its harmonics.In the process of cavitation,pressure pulsation plays a leading role in vibration.

关键词： Bulb turbine cavitation pressure fluctuation vibration correlation

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Assessment of river basin habitat quality and its relationship with disturbance factors: A case study of the Tarim River Basin in northwest china

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Journal of arid Land 2022年第2期14卷 167-185页

作者： HE Bing CHANG Jianxia GUO Aijun WANG Yimin WANG Yan LI Zhehao State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi'an University of TechnologyXi'an 710048China

The status of regional biodiversity is determined by habitat quality.The effective assessment of habitat quality can help balance the relationship between economic development and biodiversity conservation.Therefore,this study used the InVEST model to conduct a dynamic evaluation of the spatial and temporal changes in habitat quality of the Tarim River Basin in southern Xinjiang Uygur Autonomous region of china by calc ulating the degradation degree levels for habitat types that were caused by threat factors from 1990 to 2018(represented by four periods of 1990,2000,2010 and 2018).Specifically,we used spatial autocorrelation analysis and Getis-Ord Gi*analysis to divide the study area into three heterogeneous units in terms of habitat quality:cold spot areas,hot spot areas and random areas.Hemeroby index,population density,gross domestic product(GDP),altitude and distance from water source(DWS)were then chosen as the main disturbance factors.Linear correlation and spatial regression models were subsequently used to analyze the influences of disturbance factors on habitat quality.The results demonstrated that the overall level of habitat quality in the TRB was poor,showing a continuous degradation state.The intensity of the negative correlation between habitat quality and Hemeroby index was proven to be strongest in cold spot areas,hot spot areas and random areas.The spatial lag model(SLM)was better suited to spatial regression analysis due to the spatial dependence of habitat quality and disturbance factors in heterogeneous units.By analyzing the model,Hemeroby index was found to have the greatest impact on habitat quality in the studied four periods(1990,2000,2010 and2018).The research results have potential guiding significance for the formulation of reasonable management policies in the TRB as well as other river basins in arid areas.

关键词： habitat quality biodiversity InVEST model spatial heterogeneity spatial lag model human activities Tarim River Basin

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Effect of sodium alginate on phosphorus recovery by vivianite precipitation

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Journal of Environmental Sciences 2020年第7期32卷 164-169页

作者： Cong Zhang Dexiu Hu Ruijie Yang Zichen Liu State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi’an University of TechnologyXi’an 710048China

There are good prospects for phosphorus recovery from excess sludge by vivianite crystallization while a large number of extracellular polymeric substances in sludge will have impact on vivianite precipitation.In this study,as a representative of extracellular polymeric substance,the effect of sodium alginate(SA)on phosphorus recovery by vivianite precipitation under different initial SA concentrations(0–800 mg/L),p H values(6.5–9.0)and Fe/P molar ratios(1:1–2.4:1)was investigated using synthetic wastewater.The results showed that SA in low concentrations(≤400 mg/L)had little inhibitory effect on the phosphorus recovery rate.However,when the concentration of SA was larger than 400 mg/L,the phosphorus recovery rate decreased significantly with increasing SA concentrations.The inhibition rate of 800 mg/L SA was about 3 times as large as that of 400 mg/L SA.It was worth noting that the inhibitory effect of SA on vivianite precipitation decreased with increasing initial p H and Fe/P molar ratios.Additionally,SA has no obvious influence on the composition of products,but the morphology of harvested crystals was transformed from branches to plates or rods in uneven sizes.

关键词： Phosphorus recovery Excess sludge Vivianite Sodium alginate

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Numerical investigation of alleviation of undesirable effect of inter-blade vortex with air admission for a low-head Francis turbine

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Journal of Hydrodynamics 2020年第6期32卷 1151-1164页

作者： Long-gang Sun Peng-cheng Guo Luo-chang Wu state key laboratory of eco-hydraulics in northwest arid region Xi’an University of TechnologyXi’an710048China

In order to compensate for the stochastic nature of the power grid due to the tremendous development and the integration of renewable energy resources and meet its other requirements,the hydraulic turbines are forced to operate more frequently under partial load conditions with singular and misaligned flows inevitably excited by the inter-blade vortex.This paper presents numerical investigations of the unsteady characteristics of the inter-blade vortex for a low-head model Francis turbine.The SST k-ωturbulent model is used to close the unsteady Reynolds-averaged Navier-Stokes(RANS)equation.The flow structure of the inter blade vortex predicted by the numerical simulation is confirmed by experimental visualizations.It is shown that the total vortex volume in the runner sees a quasi-periodical oscillation,with significant flow separations created on the suction side of the runner blade.A counter measure by using the air admission into the water from the head cover is implemented to alleviate the undesirable effect of the inter-blade vortex.The analyses show that the development of the inter-blade vortex is significantly mitigated by the injecting air that controls and changes the spatial distribution of streamlines.Furthermore,the flow aeration with a suitable air flow rate can reduce the energy dissipation caused by the inter-blade vortex and plays a critical role in preventing the excessive amplitudes of the pressure fluctuation on the suction side of the runner blade.This investigation provides an insight into the flow mechanism underlying the inter-blade vortex and offers a reference to alleviate and mitigate the adverse consequences of the inter-blade vortex for the Francis turbine.

关键词： Numerical simulation inter-blade vortex air admission energy dissipation pressure fluctuation Francis turbine

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Erosion Behavior of NiCoCrFeNb_(0.45) Eutectic High-Entropy Alloy in Liquid-Solid Two-Phase Flow

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Acta Metallurgica Sinica(English Letters) 2022年第8期35卷 1266-1274页

作者： Kai Wang Zhenjiang Wang Jinling Lu Zhijun Wang Wei Wang Xingqi Luo state key laboratory of eco-hydraulics in northwest arid region Xi'an University of TechnologyXi'an 710048China state key laboratory of Solidification Procesing Northwestern Polytechnical UniversityXi'an 710072China

The metal components exposed to the high-velocity liquid-solid flow can be rapidly eroded by the accelerated particles.With an excellent combination of strength and toughness,the NiCoCrFeNb_(0.45)eutectic high-entropy alloy(EHEA)has emerged as a promising material to resist erosion damage.In this study,the erosion behavior of NiCoCrFeNb_(0.45)EHEA in high-velocity multiphase flow is investigated through the coupling analysis of material properties,multiphase flow,and particle–surface impact behavior.The inherent mathematical relationship is discovered between the erosion rates and the impact velocity,impact angle,and test time.The results show that the NiCoCrFeNb_(0.45)EHEA has superior erosion resistance than the commonly used machinery materials.The principal material removal mechanism is the formation and brittle fracture of the platelets,accompanied by micro-cutting and ploughing at some oblique angles.The higher work-hardenability of NiCoCrFeNb_(0.45)EHEA could mitigate the erosion damage as time proceeds,and this effect becomes more apparent as the impact angle increases.Therefore,the evolution of erosion damage with time varies significantly depending on the impact angle.Based on the test data and computational fluid dynamics(CFD)modeling of the near-wall flow field,a power exponential function relationship between erosion depth and the corresponding impact velocity at various locations on the material surface is established.

关键词： Eutectic high-entropy alloy Erosion evolution Multiphase flow Computational fluid dynamics(CFD)modeling

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Spatial variability of leaf wetness under different soil water conditions in rainfed jujube (Ziziphus jujuba Mill.) in the loess hilly region, china

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Journal of arid Land 2022年第1期14卷 70-81页

作者： GAO Zhiyong WANG Xing State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi'an University of TechnologyXi'an 710048China School of Agriculture Ningxia UniversityYinchuan 750021China

Leaf wetness provides a wide range of benefits not only to leaves,but also to ecosystems and communities.It regulates canopy eco-hydrological processes and drives spatial differences in hydrological flux.In spite of these functions,little remains known about the spatial distribution of leaf wetness under different soil water conditions.Leaf wetness measurements at the top(180 cm),middle(135 cm),and bottom(85 cm)of the canopy positions of rainfed jujube(Ziziphus jujuba Mill.)in the Chinese loess hilly region were obtained along with meteorological and soil water conditions during the growing seasons in 2019 and 2020.Under soil water non-deficit condition,the frequency of occurrence of leaf wetness was 5.45%higher at the top than at the middle and bottom of the canopy positions.The frequency of occurrence of leaf wetness at the top,middle and bottom of the canopy positions was over 80%at 17:00‒18:00(LST).However,the occurrence of leaf wetness at the top was earlier than those at the middle and bottom of the canopy positions.Correspondingly,leaf drying at the top was also latter than those at the middle and bottom of the canopy positions.Leaf wetness duration at the middle was similar to that at the bottom of the canopy position,but about 1.46-3.01 h less than that at the top.Under soil water deficit condition,the frequency of occurrence of leaf wetness(4.92%-45.45%)followed the order of top>middle>bottom of the canopy position.As the onset of leaf wetness was delayed,the onset of wet leaf drying was advanced and the leaf wetness duration was shortened.Leaf wetness duration at the top was linearly related(R^(2)>0.70)to those at the middle and bottom of the canopy positions under different soil water conditions.In conclusion,the hydrological processes at canopy surfaces of rainfed jujube depended on the position of leaves,thus adjusting canopy structure to redistribute hydrological process is a way to meet the water need of jujube.

关键词： canopy position leaf wetness rainfed jujube soil water condition loess hilly region

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Evaluation of irrigation water salinity and leaching fraction on the water productivity for crops

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International Journal of Agricultural and Biological Engineering 2020年第1期13卷 170-177页

作者： Songrui Ning Beibei Zhou Quanjiu Wang Wanghai Tao State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi’an University of TechnologyXi’an 710048China

In arid and semi-arid irrigated croplands,the excessive accumulation of soluble salts in the root zone is an extensive problem that seriously limits crop yield and water productivity(WP).To avoid affects the yield potential of crops,the application of extra irrigation for leaching of excessive salts from the root zone was required.Quantitative knowledge of effects of the irrigation water salinity and leaching fraction(LF)on the relative yield(RY)and the unit water productivity of crop evapotranspiration(UWPET)and the unit water productivity of irrigation water(UWPI)were becoming gradually important.This article provided theoretical models for estimating the UWPs(UWPET and UWPI)and optimizing leaching fraction according to irrigation water salinity.In the present study,eight levels of irrigation water salinity(ECw=0.25,0.50,0.75,1,2,3,4,and 5 dS/m)and 39 levels of LF values ranging from 0.04 to 0.80 were set and tested to assessing their effects on the RY and UWPs for four typical crops(barley,bean,wheat,and maize)with different salt tolerance levels.Almost every curve determined between the UWPs and LFs for the four crops had an inflection point.It was indicated that the UWPET and UWPI could be maximized by optimizing the LF under different irrigation water salinities.Furthermore,the linear regression relationships were established to estimate the maximum values of UWPs and their corresponding optimal LFs for four crops by using the irrigation water salinity.Moreover,the theoretical models for estimating the UWPs were validated by data of wheat from previous literature,and the models could be suitable with acceptable relative errors when LFs ranging from 0.07 to 0.17.

关键词： irrigation water salinity leaching fraction salt-tolerant crop salt stress crop yield water productivity

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Bioaccumulation and human health risk assessment of trace metals in the freshwater mussel Cristaria plicata in Dongting Lake, china

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Journal of Environmental Sciences 2021年第6期33卷 335-350页

作者： Dianbao Li Baozhu Pan Liang Chen Yuzhu Wang Taoyi Wang Jun Wang Hao Wang state key laboratory of eco-hydraulic in northwest arid region of china Xi’an University of TechnologyXi’an 710048ShaanxiChina

Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, china and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs(foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake(EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake(TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index(HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.

关键词： Trace metals Bioaccumulation Health risks Cristaria plicata Dongting lake

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Transport mechanism of eroded sediment particles under freeze-thaw and runoff conditions

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Journal of arid Land 2022年第5期14卷 490-501页

作者： WANG Tian LI Peng HOU Jingming TONG Yu LI Jing WANG Feng LI Zhanbin state key laboratory of eco-hydraulics in northwest arid region Xi'an University of TechnologyXi'an 710048China key laboratory of National Forestry Administration on ecological Hydrology and Disaster Prevention in arid regions Xi'an University of TechnologyXi'an 710048China

Hydraulic erosion associated with seasonal freeze-thaw cycles is one of the most predominant factors,which drives soil stripping and transportation.In this study,indoor simulated meltwater erosion experiments were used to investigate the sorting characteristics and transport mechanism of sediment particles under different freeze-thaw conditions(unfrozen,shallow-thawed,and frozen slopes)and runoff rates(1,2,and 4 L/min).Results showed that the order of sediment particle contents was silt>sand>clay during erosion process on unfrozen,shallow-thawed,and frozen slopes.Compared with original soils,clay and silt were lost,and sand was deposited.On unfrozen and shallow-thawed slopes,the change of runoff rate had a significant impact on the enrichment of clay,silt,and sand particles.In this study,the sediment particles transported in the form of suspension/saltation were 83.58%–86.54%on unfrozen slopes,69.24%–84.89%on shallow-thawed slopes,and 83.75%–87.44%on frozen slopes.Moreover,sediment particles smaller than 0.027 mm were preferentially transported.On shallow-thawed slope,relative contribution percentage of suspension/saltation sediment particles gradually increased with the increase in runoff rate,and an opposite trend occurred on unfrozen and frozen slopes.At the same runoff rate,freeze-thaw process had a significant impact on the relative contribution percentage of sediment particle transport via suspension/saltation and rolling during erosion process.The research results provide an improved transport mechanism under freeze-thaw condition for steep loessal slopes.

关键词： freeze-thaw runoff conditions erosion process sediment particles transport mechanism

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