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Shi Y.,Southwest University | Shi Y.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | Sun Y.-C.,Southwest University | Liang Z.-B.,Southwest University | And 3 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

The condensation effect has made high mountains the storage vault of durable organic pollutants. This research measured the content and constitutes of polycyclic aromatic hydrocarbons (PAHs) in 10 topsoil samples collected at different altitudes from the south slope of Chongqing Jinfo Mountain by gas chromatograph-mass spectrometer (GC/MC). And the pollution source of PAHs was analyzed by ratio method and principal component regression. The ecological risk of PAHs was evaluated using BaP toxic equivlants (TEQBaP) The results showed that the concentrations of 16 priority PAHs in topsoil ranged from 240-2121 ng·g-1. The average value of PAHs was 849 ng·g-1, and 2 to 3-ring PAHs were the dominant compounds. The concentrations of 7 carcinogenic PAHs accounted for 17.8% of total PAHs averagely. In the research area, various-ring PAHs and gross PAHs increased with the rise of altitude. The increase of low-ring PAHs was most obvious, and the volatility of high-ring PAHs was relatively high. But the ratio of different-ring PAHs in gross PAHs showed no regularity with the rise of altitude. The PAHs of soil in the research area mainly came from the oil sources, oil products, and combustion sources of coal and biomass. In the research area, the soil has been polluted to a certain extent, but the toxicity risk is relatively low. ©, 2015, Science Press. All right reserved. Source


Liu X.,Southwest University | Liu X.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | Yang Y.,Southwest University | Yang Y.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | And 12 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

Geochemical dynamics of cave water were monitored to unveil its variation and controlling factors from October 2009 to December 2013 in Jiguan Cave, west of Henan province, southeastern coast of the loess plateau. The results showed that: (1) the hydro-chemical types of the cave water are HCO3--Ca2+-Mg2+ and HCO3--Mg2+-Ca2+. HCO3- are over 80% of the anions, Ca2+ and Mg2+ are the dominate cations, and ground river keeping in erosion and pool water drips in deposition all the year. (2) Dripping water and pool water in Ji guan cave can respond perfectly to the change of external climate environment, which geochemistry indexes possess the extraordinary seasonal effects. (3) The concentration changes of the Ca2+, Mg2+, SO42- responded sensitively to annual precipitation change. Ca2+, Mg2+, SO42- rise in waterlogging year and fall in drought year. Because HCO3- controlled by CO2 concentration. HCO3- concentration showed a unconspicuous response to the change of external climate environment. (4) The concentration changes of Ca2+, Mg2+, SO42- have no obvious seasonal variation and showed a unconspicuous response to the change of external climate environment. ©, 2015, Science Press. All right reserved. Source


Sun Z.,Southwest University | Sun Z.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | Yang Y.,Southwest University | Yang Y.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | And 14 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

The stable isotopes of atmospheric precipitation that affect the isotopes of speleothem and cave water are controlled by a variety of factors, such as temperature, rainfall amount, altitude, vapor source and others. Knowledge in the factors causing rainfall stable isotopes change is one of the keys to understanding the cave water stable isotopes change of monsoon-sensitive area in the north-south China intersection. The samples collected from 4 ground water sites in Jiguan Cave and the instantaneous heavy rain during Aug. 4th-6th, 2015 were analyzed, and combined with the precipitation oxygen and hydrogen isotopes data for samples from almost 6 years (2009-2015) collected in Jiguan Cave of Luanchuan County in Henan Province, leading to the following findings: (1) The precipitation was divided into 2 stages with different vapor sources (high-altitude water vapor from the South China Sea and inland areas from near the ground to evaporate moisture) that could be recorded in the δ18O of single rainfall by HYSPLIT model. (2) The evaporation of stage 2 masked the temperature effect to some extent, which also decreased the slope and intercept of LMWL and d-excess of precipitation. (3) The δ18O values feature of cave drip water in Jiguan Cave during this rainfall was mainly a response to the summer monsoon precipitation from sea source vapor. The cave drip water of Jiguan Cave responded to the heavy rain very quickly, and the time was~3 h. The δ18O of drip became heavier when dripping rate increased and then decreased slowly. The same pattern could be found in underground river with slight delay, and the pool near the cave entrance reflected the difference of precipitation δ18O in two stages. © 2016, Science Press. All right reserved. Source


Ren K.,Southwest University | Ren K.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | Yang P.-H.,Southwest University | Yang P.-H.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | And 5 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

The groundwater discharge and heavy metal concentrations (Mn, Pb, Cu and As) at the outlet of Nanshan Laolongdong karst subterranean river, located at the urban region in Chongqing, were observed during the rainfall events. Analysis of flow and concentrations curves was employed to study their responses to the rainfall events and explore the internal structure of karst hydrological system. Principal component analysis (PCA) and measurements were used to identify the sources of heavy metals during rainfall. The result showed that the discharge and concentrations of the heavy metals responded promptly to the rainfall event. The variation characteristics of flow indicated that Laolongdong subterranean river system belonged to a karst hydrological system including fractures together with conduits. Urban surface runoff containing large amounts of Mn, Pb and Cu went directly to subterranean river via sinkholes, shafts and karst windows. As a result, the peak concentrations of contaminants (Mn, Pb and Cu) flowed faster than those of discharge. The major sources of water pollution were derived from urban surface runoff, soil and water loss. Cave dripwater and rainwater could also bring a certain amount of Mn, Pb and As into the subterranean river. Urban construction in karst areas needs scientific and rational design, perfect facilities and well-educated population to prevent groundwater pollution from the source. ©, 2015, Science Press. All right reserved. Source


Yu Z.-L.,Southwest University | Yu Z.-L.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | Yang P.-H.,Southwest University | Yang P.-H.,Field Scientific Observation & Research Base of Karst Eco Environments at Nanchuan in Chongqing | And 7 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

Snow can preserve the atmospheric information, which makes it become a good media in studying regional environment. Jinfo Mountain with an elevation of 2 251.1 m, located at the transition zone between Sichuan basin and Yunnan-Guizhou Plateau, is deeply affected by human activities, and snowfall is the main form of precipitation during the winter. While the literature focus on single spherical particles in this area is uncommon. Five snow samples were collected, and determined morphology and chemical composition of 132 single spherical particles by the scanning electron microscope couples with energy dispersive X-ray spectrometer (SEM-EDS). Results show that snowfall in Jinfo Mountain includes the massive fly ash particles with 1.64 μm in average diameter and 1.09 in average roundness which contains smooth particles, rough particles and soot particles, accounting for 80.31%, 14.39% and 5.30% of statistical particles respectively. Furthermore, on the basis of chemical information obtained from EDS, the fly ash particles counted in this research can be classified into 5 types, namely, Si-dominant particles, C-dominant particles, Fe-dominant particles, Al-dominant particles and Ti-dominant particles, which make up 34.09%, 49.24%, 12.88%, 2.27% and 1.52% respectively. In conclusion, it can be inferred, based on the analysis of meteorological information, the properties of fly ash particles, and backward air mass trajectory and dispersion analysis, that C-dominant fly ash mainly comes from daily life and industry activities, Si-dominant fly ash particles may originate from the plant industry located in west Chingqing, north of Guizhou province, central of Hunan province, Zhejiang province, Jiangxi province and the west of Guangdong province, while the activities of foundry and iron or steel plants in the west of Chongqing, the north of Guizhou province and the central of Hunan province may be the main sources of Fe-dominant fly ash particles in our samples. © 2015, Science Press. All right reserved. Source

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