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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

Examination on behavior of tip leakage flow in a three-stage gas-liquid two-phase flow pump

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Journal of Hydrodynamics 2024年第5期36卷 843-853页

作者： Si-na Yan Xing-qi Luo Jian-jun Feng Shuai-hui Sun Guo-jun Zhu Xin Wu state key laboratory of eco-hydraulics in northwest arid region Xi’an University of TechnologyXi’an710048China

Tip leakage flow(TLF)trajectory in a pump with gas entrainment is investigated via visualization experiments and numerical *** position of tip leakage vortex(TLV)is determined accurately by numerical *** high liquid flow rate(Q_(l))and high inlet gas volume fraction(IGVF)conditions,TLF flows from suction surface to pressure surface near the leading edge of blade,and the direction of TLF gradually changes along the chord which flows from pressure surface to suction surface near the tailing *** angle between TLF and blade mean camberline increases progressively as either Q_(l)or IGVF decreases,and starting position of TLV moves towards leading edge *** Q_(l)or IGVF decreases,value of vorticity increases and high vorticity region moves towards leading *** entropy production rate at blade tip clearance is high,and entropy diffuses from pressure surface to suction surface due to jet flow in blade tip *** greater the amount of accumulated gas there is,the greater the amount of entropy in the *** addition,when gas is entrained in pump,there are many low frequency fluctuations generated in blade tip clearance.

关键词： Gas-liquid two-phase flow multistage pump entropy production tip leakage vortex(TLV) unstable characteristics

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 *** enhance their stability,this study examines the effects of runner cavitation on draft tube pressure fluctuation and vibration in bulb turbine through experimental *** 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 *** 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 *** enhances the high-frequency vibration on the wall of runner *** root mean square(rms)of the vertical vibration component IMF3,the horizontal vibration components IMF2,IMF4 are linearly negatively correlated with the cavitation *** associated component between cavitation-induced vibration and pressure pulsation signal is 16f_(n)and its *** the process of cavitation,pressure pulsation plays a leading role in vibration.

关键词： Bulb turbine cavitation pressure fluctuation vibration correlation

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 *** paper presents numerical investigations of the unsteady characteristics of the inter-blade vortex for a low-head model Francis *** SST k-ωturbulent model is used to close the unsteady Reynolds-averaged Navier-Stokes(RANS)*** flow structure of the inter blade vortex predicted by the numerical simulation is confirmed by experimental *** 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 *** 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 ***,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 *** 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

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 *** 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 *** results showed that SA in low concentrations(≤400 mg/L)had little inhibitory effect on the phosphorus recovery ***,when the concentration of SA was larger than 400 mg/L,the phosphorus recovery rate decreased significantly with increasing SA *** inhibition rate of 800 mg/L SA was about 3 times as large as that of 400 mg/L *** was worth noting that the inhibitory effect of SA on vivianite precipitation decreased with increasing initial p H and Fe/P molar ***,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

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 *** few exceptions in concentration of Cr,most of fish species showed lower concentrations of the 8 metals than legislation *** fishes had significantly higher values of δ^(15)N(possessing higher trophic level)and metal concentrations than planktivorous and herbivorous ***,demersal fishes showed higher concentrations of Cu,Zn,Cd and Pb than pelagic and benthopelagic *** found positive correlations between concentrations of Fe,Pb and Hg and δ^(15)N ratio,confirming the biomagnification of the three metals through trophic *** 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 *** 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 *** 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 *** 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

Driving forces behind the spatiotemporal heterogeneity of land-use and land-cover change:A case study of the Weihe River Basin,China

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Journal of arid Land 2023年第3期15卷 253-273页

作者： WU Jingyan LUO Jungang ZHANG Han YU Mengjie state key laboratory of eco-hydraulics in northwest arid region Xi'an University of TechnologyXi'an 710048China

The impact of socioeconomic development on land-use and land-cover change(LUCC)in river basins varies spatially and *** the spatiotemporal evolutionary trends and drivers of LUCC under regional disparities is the basis for the sustainable development and management of *** this study,the Weihe River Basin(WRB)in China was selected as a typical basin,and the WRB was divided into the upstream of the Weihe River Basin(UWRB),the midstream of the Weihe River Basin(MWRB),the downstream of the Weihe River Basin(DWRB),the Jinghe River Basin(JRB),and the Luohe River Basin(LRB).Based on land-use data(cultivated land,forestland,grassland,built-up land,bare land,and water body)from 1985 to 2020,we analyzed the spatiotemporal heterogeneity of LUCC in the WRB using a land-use transfer matrix and a dynamic change *** driving forces of LUCC in the WRB in different periods were detected using the GeoDetector,and the selected influencing factors included meteorological factors(precipitation and temperature),natural factors(elevation,slope,soil,and distance to rivers),social factors(distance to national highway,distance to railway,distance to provincial highway,and distance to expressway),and human activity factors(population density and gross domestic product(GDP)).The results indicated that the types and intensities of LUCC conversions showed considerable disparities across different sub-basins,where complex conversions among cultivated land,forestland,and grassland occurred in the LRB,JRB,and UWRB,with higher dynamic change before *** conversion of other land-use types to built-up land was concentrated in the UWRB,MWRB,and DWRB,with substantial increases after ***,the driving effects of the influencing factors on LUCC in each sub-basin also exhibited distinct diversity,with the LRB and JRB being influenced by the meteorological and social factors,and the UWRB,MWRB,and DWRB being driven by human activity ***,the interaction

关键词： land-use and land-cover change(LUCC) spatial heterogeneity land-use conversion dynamic change model GeoDetector human activities Weihe River Basin

Refined mathematical model for the breaching of concrete-face sand-gravel dams due to overtopping failure

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Journal of Mountain Science 2023年第3期20卷 670-687页

作者： QIU Wen LI Yan-long WEN Li-feng WANG Jing YIN Qiao-gang state key laboratory of eco-hydraulics in northwest arid region Xi'an University of TechnologyXi'an 710048China

Overtopping is one of the main reasons for the breaching of concrete-face sand-gravel dams(CFSGDs).In this study,a refined mathematical model was established based on the characteristics of the overtopping breaching of *** model characteristics were as follows:(1)Based on the Renormailzation Group(RNG)k-εturbulence theory and volume of fluid(VOF)method,the turbulent characteristics of the dam-break flow were simulated,and the erosion surface of the water and soil was tracked;(2)In consideration of the influence of the change in the sediment content on the dam-break flow,the dam material transport equation,which could reflect the characteristics of particle settlement and entrainment motion,was used to simulate the erosion process of the sand gravels;(3)Based on the bending moment balance method,a failure equation of the concrete face slab under dead weight and water load was *** proposed model was verified through a case study on the failure of the Gouhou *** results showed that the proposed model could well simulate the erosion mode of the special vortex flow of the CFSGD scouring the support body of the concrete face slab inward and reflect the mutual coupling relationship between the dam-break flow,sand gravels,and concrete face *** with the measured values,the relative errors of the peak discharge,final breach average width,dam breaching duration,and maximum failure length of the face slab calculated using the proposed model were all less than 12%,thus verifying the rationality of the *** proposed model was demonstrated to perform better and provide more detailed results than three selected parametric models and three simplified mathematical *** study results can aid in establishing the risk level and devising early warning strategies for CFSGDs.

关键词： Concrete-face sand-gravel dam Overtopping Dam-break flow Concrete face slab failure Refined mathematical model

Dynamic response of carbon storage to future land use/land cover changes motivated by policy effects and core driving factors

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Journal of Plant ecology 2024年第5期17卷 120-140页

作者： Han Zhang Jungang Luo Jingyan Wu Hongtao Dong state key laboratory of eco-hydraulics in northwest arid region Xi’an University of TechnologyXi’an 710048China

The evolution of land use/land cover(LULC)patterns significantly influences the dynamics of carbon storage(CS)in terrestrial *** response to future environmental changes,however,most studies fail to synthesize the effects of policy pathways and evolving core driving factors on LULC *** article presents a systematic framework to assess the dynamic response of the terrestrial ecosystem CS to future LULC *** investigating spatiotemporal characteristics and driving forces,policy effects and future core driving factors are integrated into the improved Markov–future land use simulation model to project LULC across diverse *** the Integrated Valuation of ecosystem Service and Tradeoff model is coupled to explore CS dynamics with LULC *** framework was applied to the Weihe River *** finding reveals that the overall proportion of cultivated land,forestland and grassland is above 85%and is significantly influenced by policy ***,temperature,population density and gross domestic product are core driving factors of LULC ***-interval projection is a viable approach to mitigate policy impacts by avoiding error propagation while coupling future core driving factors to improve LULC projection *** protection should be emphasized in the *** rate of increase in CS is 1.25 and 1.63 times higher than the historical trend and economic development scenario,respectively,which alleviates carbon loss from the expansion of built-up *** research provides a valuable reference for future insight and optimization of ecological conservation strategies.

关键词： carbon storage LULC projection random forest Markov-FLUS InVEST model