Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas

Yanta, China

Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas

Yanta, China
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Li Y.,Chang'an University | Li Y.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Lu R.,Chang'an University | Li W.,Chang'an University | And 2 more authors.
Journal of Aerosol Science | Year: 2017

In recent years, atmospheric particulate matter (PM) has become one of the top pollutants affecting the air quality and human health in Xi'an, the largest city in semi-arid inland of China. Few studies have been carried out on the microbial fraction of PM (defined as bioaerosols) in this region, especially under specific weather conditions. In this study, airborne microbial samples in Xi'an city were collected from Aug. 2014 to Jul. 2015. The concentrations and size distributions of airborne viable bacteria and fungi were characterized under different weather conditions (e.g. sunny, cloudy, rainy and hazy days). The results showed that the concentrations of airborne viable microbes in Xi'an were lower than those in most cities worldwide due to the semi-arid climate feature. The concentrations of airborne viable microbes varied by weather conditions, with the highest value observed on hazy days and the lowest observed on rainy days. In particular, the mean concentrations of viable bacteria and fungi on the hazy days (1311±371 and 896±559 CFU/m3) exceeded the recommended permissible limit values in China. Moreover, the size distribution of airborne viable bacteria presented a similar unimodal pattern under four weather conditions, while no clear distribution pattern for airborne viable fungi was found in the non-haze weathers. Another important finding was that more than 60% viable bioaerosols were in respirable size range under all weather conditions. The present results can improve our understanding on the influence of viable bioaerosols on human health and air quality in semi-arid regions under various weather conditions. © 2017 Elsevier Ltd


Qian H.,Chang'an University | Qian H.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Wu J.,Chang'an University | Wu J.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | And 4 more authors.
Hydrological Processes | Year: 2014

The Yinchuan Plain has more than 2000years of history of irrigation by diverting water from the Yellow River. Currently, the amount of water diverted from the Yellow River is about 21.7 times the water formed on the plain as a result of precipitation and inflow of groundwater. Under the intensive influence of irrigation, the plain changed from a desert into a rich and populous area, earning its name as 'South China Beyond the Great Wall', with lakes scattered across the Yinchuan Plain just as stars in the sky. In this research, 17 representative lakes were sampled to analyze and study 2H and 18O content; the results showed that lakes on the plain have undergone obvious non-equilibrium evaporation. Recharges of the lakes can be divided into three types: recharge from the Yellow River, from groundwater and from both of these. The Craig-Gordon non-equilibrium evaporation model for isotope fractionation was used to estimate the evaporation proportion of each lake. The results showed that evaporation from lakes on Yinchuan Plain is generally extensive under the dry climatic conditions. Most lakes have an evaporation proportion of over 25%, with the largest originating from Shahu lake and Gaomiaohu lake in the northern part of the plain, at 42.5% and 42.8%, respectively. The evaporation proportions calculated on the basis of 18O and 2H are very close to each other. This shows that the method used in this paper is feasible for estimating the evaporation proportions of lakes in areas with a heavy anthropogenic influence. © 2013 John Wiley & Sons, Ltd.


Li Y.,Chang'an University | Li Y.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Li Y.,Harbin Institute of Technology | Yang L.,Chang'an University | And 3 more authors.
Aerosol and Air Quality Research | Year: 2013

To characterize the emission of microbial aerosols from the widely used municipal sewage treatment plants (MSTP) in China, an Andersen six-stage impactor and the culture method were employed to determine the concentrations and size distributions of airborne viable bacteria, fungi and actinomycetes in a sewage treatment plant with an oxidation ditch process in Xi'an in summer. The results showed that the concentrations and size distributions of each of the airborne microorganisms varied greatly at different phases of sewage treatment process. The highest bacteria (7866 ± 970 CFU/m3) and actinomycetes concentrations (2139 ± 229 CFU/m3) were found in the sludge-dewatering house while the highest fungi concentration (2156 ± 119 CFU/m3) at the oxidation ditch. The particle size distributions showed that similar single-peak pattern for airborne actinomycetes, bacteria and fungi. Another important finding was that about 52% of airborne bacteria, 62% of airborne fungi and 65% of airborne actinomycetes were in respirable size range (less than 3.3 μm), indicating that most microbial aerosols from MSTP could easily penetrate into the human alveolus. Finally, the order of the count median diameters of different microbial aerosols was found to be similar at each phase, that is, airborne bacteria > airborne fungi > airborne actinomycetes. This implied that airborne actinomycetes emitted from MSTP might have a more significant effect on public health and urban air quality than bacteria and fungi. © Taiwan Association for Aerosol Research.


Li P.,Chang'an University | Li P.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Qian H.,Chang'an University | Qian H.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | And 6 more authors.
Mine Water and the Environment | Year: 2013

A hydrogeochemical study was conducted in the Dongsheng Coalfield, Ordos Basin, China, to identify the mechanisms responsible for the chemical compositions of the shallow groundwater and to document water quality with respect to agricultural and drinking supply standards, prior to mining. Tri-linear diagrams, principal component analysis, and correlation analysis were used to reveal the hydrogeochemical characteristics of the shallow groundwater, and the potential water-rock interactions. In general, the major cations and anions were present at low concentrations, but were relatively higher around Jiushenggong than elsewhere in the study area. Groundwater around Jiushenggong has a long residence time and is also subject to extensive evapotranspiration. The dominant hydrochemical facies are HCO3-Ca, HCO3-Na, and mixed HCO3-Ca·Na·Mg types. Increases in major ion concentrations along the flow path, including Na, Cl, and SO4, coincide with increases in total dissolved solids. The predominant mechanism controlling groundwater chemistry proved to be the dissolution of carbonates, gypsum, and halite. Cation exchange and mixing with local recharge water are also important factors. The shallow groundwater quality in the study area is suitable for agricultural and drinking purposes. © 2013 Springer-Verlag Berlin Heidelberg.


Qian H.,Chang'an University | Qian H.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Li P.,Chang'an University | Li P.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | And 4 more authors.
Environmental Earth Sciences | Year: 2013

The isotopic characteristics of hydrogen and oxygen of various water bodies in the Yinchuan plain were investigated. A total of 131 water samples were collected and another 99 water samples collected by other scholars and the International Atomic Energy Agency were referred to in the study. The stable isotopic compositions of precipitation and lake waters are influenced by dry climate and strong evaporation of the area, and the slope of local meteoric water line and lake water line are smaller than that of global meteoric water line. The isotopic compositions of the Yellow River water are significantly lower than the weighted averages of local atmospheric precipitation and are controlled by the runoff of upstream areas. The isotopes of phreatic water suggest that the single phreatic water is predominantly recharged by the bedrock fissure water of Helan Mountain, while the phreatic water in multilayer structure area is recharged by multiple sources. The confined waters in the area may be recharged under cooler climate conditions than the present, which makes the heavy isotopes depleted. The 3H contents of various water bodies are in the following order: the Yellow River water > multilayer phreatic water > single phreatic water > lake water > drainage ditch water > upper confined water > lower confined water. This is in accordance with the recharge, discharge and circulation conditions of the specific water bodies. The isotope compositions of waters in the Yinchuan plain are mainly affected by external water recharge rather than local precipitation. This study is meaningful and helpful in understanding the groundwater flow systems and water cycle in the area. © 2012 Springer-Verlag Berlin Heidelberg.


Li P.,Chang'an University | Li P.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Wu J.,Chang'an University | Wu J.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | And 2 more authors.
Environmental Earth Sciences | Year: 2013

Groundwater is an important water source for agricultural irrigation in Penyang County. Some traditional methods such as irrigation coefficient, sodium adsorption ratio, total alkalinity, total salinity and total dissolved solids were employed to assess groundwater quality in this area. In addition, an improved technique for order preference by similarity to ideal solution model was applied for comprehensive assessment. The origin of major ions and groundwater hydrogeochemical evolution was also discussed. Groundwater in Penyang County contains relative concentrations of dominant constituents in the following order: Na+ > Ca2+ > Mg2+ > K+ for cations and HCO3 - > SO4 2- > Cl- > CO3 2- for anions. Groundwater quality is largely excellent and/or good, suggesting general suitability for agricultural use. Calcite and dolomite are found saturated in groundwater and thus tend to precipitate out, while halite, fluorite and gypsum are unsaturated and will dissolve into groundwater during flow. Groundwater in the study area is weathering-dominated, and mineral weathering (carbonate and silicate minerals) and ion exchange are the most important factors controlling groundwater chemistry. © 2012 Springer-Verlag Berlin Heidelberg.


Gao Y.,Chang'an University | Gao Y.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Qian H.,Chang'an University | Qian H.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas
Conference Proceedings of the 3rd International Symposium on Project Management, ISPM 2015 | Year: 2015

To assess the vulnerability of water resources in Guanzhong plain, this paper adopts the Principal Component Analysis approach which can capture multiple indicators of water resources vulnerability in a single or small number of vulnerability indices. Based on the evaluation of initial nineteen indicators, which were finally aggregated into three principal component of vulnerability, the intensive exploitation and rapid expansion of population became evident. According to the model of vulnerability assessment and the threshold value, the holistic vulnerability index of five cities in Guanzhong plain demonstrated that the comprehensive vulnerability assessment of water resources according to the order from high to low are Xi'an, Xianyang, Weinan, Tongchuan, Baoji. The comprehensive and easily interpretable findings of the study are expected to help decision makers reach sound solutions to reduce water resources vulnerability in Guanzhong plain.


Li Y.,Chang'an University | Li Y.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Zhang H.,Chang'an University | Qiu X.,Research Professional Committee of All China Environment Federation | And 2 more authors.
Aerosol and Air Quality Research | Year: 2013

A microbial risk assessment was carried out for the rotating-brush aerator used during summer in a wastewater treatment plant (WWTP) of Xi'an, China. Bacterial aerosols were first collected by an Andersen cascade impactor at selected sampling sites near the rotating-brush aerator. The concentrations of airborne bacteria were used to obtain microbial emission rate by back calculation. The downwind concentrations of airborne bacteria were then calculated by a modified Gaussian dispersion model accounting for environmental impact and microorganism decay. Subsequently, the exposure parameters suitable for Chinese people were incorporated into a risk assessment model to evaluate non-carcinogenic risks of airborne mesophilic bacteria to sewage workers and surrounding residents. The results indicate that both mean bacterial concentrations at ground level and the exposure hazard quotient decrease rapidly with downwind distance. The exposure hazard quotient by inhalation route is over 105 times more than by dermal contact route for both children and adults, suggesting that inhalation route is the major exposure pathway of microbial aerosol intake for surrounding people. Although the present model gives acceptable low risk values at various downwind distances, it is worth noting that health risks of microbial aerosols associated with rotating-brush aeration for children are generally much more than those for adults. © Taiwan Association for Aerosol Research.


Jing J.,Chang'an University | Hui Q.,Chang'an University | Hui Q.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Yu-Fei C.,Chang'an University | Wen-Juan X.,Chang'an University
Journal of Chemistry | Year: 2013

The basic theory and calculating processes of matter element extension method are discussed in detail. Mass balance simulation is used to study the changes of groundwater chemistry. Results show that calcite and dolomite are oversaturated, while gypsum, fluorite, and halite are unsaturated in the simulation path; so calcite precipitates, while gypsum, fluorite, halite, and dolomite dissolve. The changing tendency of Ca2+/Na+ is apparent. Because of the dissolution and precipitation of minerals, the content of each ion changes. Parameters of groundwater are basically within the permissible limits and meet the requirement of drinking water standards. By comparing the evaluation results obtained from matter element extension method, osculating value method based on entropy weight, and principal component analysis method, it is proved that matter element extension is an effective and reasonable method for groundwater quality assessment. The converting tendency of groundwater quality is judged based on the extension indexes; this characteristic is unique of matter element extension method. © 2013 Jin Jing et al.


Li P.,Chang'an University | Li P.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | Qian H.,Chang'an University | Qian H.,Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas | And 8 more authors.
Environmental Earth Sciences | Year: 2014

Fluoride (F-) has significant impacts on human health. High fluoride groundwater (up to 1.90 mg/L) has been found in upper confined aquifer underlying the first terrace of Weihe River during a hydrogeological investigation for water supply in 2005. To reveal the occurrence and hydrogeochemistry of high F- groundwater, hydrogeochemical tools such as saturation index, ionic ratios and correlation analysis were used in this study. The study shows that the concentrations of most physiochemical parameters from phreatic water, influenced by intensive evaporation and anthropogenic activities such as unregulated sewage and excreta disposal and agricultural practices in the area, are higher than those of confined water. The F- concentration in phreatic water is within the acceptable limits set by China and the World Health Organization (WHO), while that of upper confined water shows a decreasing trend northwestward as the Weihe River approaches, with F- concentration in the first terrace beyond the national and the WHO standards. High F- groundwater is observed in alkaline environment associated with high Na+, pH, HCO3 - and low Ca2+ and Mg2+. The enrichment of F- is controlled by geologic and hydrogeological conditions, fluorine-bearing minerals presented in alluvial formations and their dissolution/precipitation under the alkaline environment along groundwater flow. Ion exchange, human activities and the mixing of different recharge waters may influence the enrichment of F- as well. © 2013 Springer-Verlag Berlin Heidelberg.

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