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Study on water vapor transport is beneficial for better understanding the process of extreme precipitation. However, the precipitation system is complex and precipitation isotopes exhibit randomness, which makes it large uncertainty to use precipitation isotopes to trace water vapor transport. Information entropy has been employed to study the probability distribution characteristics of precipitation isotopic compositions in China, and it shows a strong linear relationship between hydrogen and oxygen precipitation isotopic information entropies, with a slope that is close to one. The spatial and temporal distributions of precipitation isotope information entropy were compared with the mean value of precipitation isotopes. Results showed that the spatial distribution of precipitation isotopic information entropy can suitably reveal the movement of water vapor from the ocean to continents, but this feature is not reflected by the spatial distribution of the mean value of precipitation isotopes. Precipitation isotope information entropy was applied to trace the three moisture corridors driven by monsoon system in China. Results showed that the spatial distribution of precipitation isotope information entropy can accurately reflect the vapor source and movement of the three moisture corridors and their seasonal changes. [ABSTRACT FROM AUTHOR]

Spatiotemporal variation of nitrate (NO3 ¯ ) and isotope components were investigated in the karst and non-karst sub-basins, to clarify the influence of hydrogeological conditions and underlying surface properties on the source and migration of nitrate in water. The research areas were selected as the Mudong and the Jingui sub-basin in the Qingshitan Reservoir Irrigation District of Lijiang River Basin in southwest China. Both small karst watersheds were also dominated by agricultural activity. Multiple isotopes (δD-H2O, δ18O-H2O, δ15N-NO3 ¯, and δ18O-NO3 ¯ ) and the Bayesian Model Stable Isotope Analysis in the R (SIAR) model were applied to compare the multiple potential nitrate sources in the water. The results indicated that the spatial and temporal variation of nitrate in water depended on the hydrogeological conditions and the associated topography, soil characteristics, and land use types of the sub-basin. Total nitrogen (TN) was mainly formed by NO3 ¯ and NH4 + in the river, where the proportion of NO3‾ was slightly higher while decreasing along the river. TN was overwhelmingly dominated by NO3‾ in the shallow groundwater. Nitrification was the dominant process of NO3 ¯ formation and transformation. The Jingui sub-basin included the woodland with a thicker soil layer, while the Mudong sub-basin was mainly agricultural land with the karst development and the discontinuous thin soil layer. The ranges of mean NO3 ¯ concentration (0.19-15.84 mg/L), and the isotope values of δD-H2O (from -44.08‰ to -19.63‰), δ18O-H3O (from -7.24‰ to -1.55‰), δ15N-NO3 ¯ (from -1.65‰ to 53.98‰), and δ18O-NO3 ¯ (from 0.04‰ to 13.74‰) in the Mudong sub-basin, were all greater than those in the Jingui sub-basin. In terms of spatial distribution, the mixing of nitrogen fertilizer infiltration from the orchard of exposed karst stone mountain in the north recharge area and manure & septic waste infiltration from the village groups were not smoothly dispersed and discharged in the central tectonic basin region, resulting in the high concentration of NO3 ¯ (the mean concentration range from 11.96 to 15.84 mg/L) and the high isotope value of δ15N-NO3 ¯ (from 0.65‰ to 28.23‰) and δ18O-NO3 ¯ (from 2.46‰ to 14.43‰) in the water of G4-G7 wells. The contributions of NO3 ¯ sourced from the soil nitrogen in the dry season, as well as the manure and septic waste in the wet season in the Mudong sub-basin, were less than those in the Jingui sub-basin. The reason was the low capacity of water storage in the thin soil layer that was formed by the weathering of carbonate rocks, together with the strong permeability of the shallow soil layer in the Mudong sub-basin. Consequently, spatial and temporal variations of nitrate pollution and migration in water were achieved under karst hydrogeological conditions and underlying surface properties. The finding can provide decision support for the control of agricultural non-point source pollution and the improvement of the water environment in karst and non-karst areas. [ABSTRACT FROM AUTHOR]

Stable isotope ratios of carbon, nitrogen, hydrogen and oxygen act as "nature's recorder". A s a carrier for individual human information, human hair can be measured by isotope ratio mass spectrometry ORMS) to translate into information about people's dietary habits, health condition and life track. The basic principle behind establishing dietary lifestyle using isotopic profiles of human hair is the fact that the body's only source of C, N is a person's staple diet. It may have significant differences in carbon, nitrogen isotopic compositions of human hair that are living at different regions. The aim of the study was to analyze the discrepancy of 15N and 13C stable isotope ratios in human hair collected from different cities, and explore the relationship between carbon and nitrogen isotope ratios and human groups, such as gender and age. The carbon and nitrogen isotope ratios in the human hair of 247 local residents from 8 different cities were investigated by IRMS. The results showed that there were significant difference in carbon and nitrogen stable isotope ratios of human hair from different cities. The value of δ13 C was negatively correlated with vegetable consumption per capita. The value of δ15N was positively correlated with meat consumption per capita, and might be increased by high intake of fish. The relationship between δ13C, δ15N and the factors of gender and age demonstrated that there were no significant difference between males and females, but the age of females showed a weakly negative correlation with δ13 C. By comparing the data of this paper and other literatures, the carbon and nitrogen stable isotopes in the hair of residents in China were different from other countries, which implied that there were various dietary habits in different countries. [ABSTRACT FROM AUTHOR]

In order to reduce soil erosion and improve ecological environment, the Chinese government implemented the Grain for Green Project in 1999, in which numerous croplands were converted to grasslands, forestlands, or free land for natural plant succession. The ecological construction not only significantly changes the vegetation cover conditions of the watershed, but also changes the hydrological processes of the watershed. In order to understand the changes of ecological and hydrological processes under different ecological construction conditions, 414 water samples were collected in the governance river basin of Jiuyuangou Watershed and 300 water samples were collected in the natural river basin of Peijiamao Watershed, which are sub basins of Wuding River. The water samples included precipitation, river water, well water, reservoir water and snow water. Each water samples had three replicates. Based on stable isotope technology, the hydrogen and oxygen isotope characteristics were analyzed in different water samples. The effects of ecological construction on water transmission process and transformation characteristics between different water bodies in different seasons were also evaluated in this research. The results showed that the amplitude of precipitation isotope values were greater than the river water and well water isotope values. In addition, the river water and reservoir water had stronger evaporation fractionation than other water samples and well water was relatively stable. The local meteoric water line was δD=7.09δ18O+1.29 in the governance river basin of Jiuyuangou watershed and δD=6.71δ18O-3.25 in the natural river basin of Peijiamao watershed. The slope and intercept of the local meteoric water line in Jiuyuangou watershed was greater than that in Peijiamao watershed. The water supply source of river water, well water and reservoir water were mostly from precipitation. At the same time, precipitation and snow water had similar sources. During the dry season (from December to June), the temperature was low and during the wet season (from July to November), it was high, and the precipitation was mainly distributed in June to November. The isotope values were low in the wet season, and dry season isotope values were high. The isotope values were positively correlated with the precipitation, and negatively correlated with the temperature. The isotope values of river water and well water showed a similar trend of variation, which became enrichment with the main channel flow. The oxygen isotope value was used to calculate the supply ratio of precipitation, river water and well water in dry season and wet season. In dry season, precipitation and well water supplied river water, and the supply ratio was 24.66%, 75.34% and 83.81%, 16.19%, respectively. In wet season, well water was supplied by precipitation and river water, and the supply ratio was 14.75%, 85.25% and 48.06%, 51.94%, respectively. Ecological construction had significantly changed the ecological and hydrological processes. The acceleration of ecological construction had a significant impact on the transformation of different water bodies in the river basin of Loess Plateau. The present research could provide technical support and theoretic foundation for the study of ecological and hydrological processes and ecological environment protection on the Loess Plateau. [ABSTRACT FROM AUTHOR]

This paper established the identification technology of the main root origin of three-year-old spring Panax notoginseng aiming at providing theoretical basis for the protection and traceability of geographical indication products of P. notoginseng. Forty-four samples of three-year-old spring P. notoginseng from Guangxi Baise, Yunnan Wenshan, Yunnan new cultivating regions. The stable isotopic ratios of carbon, nitrogen, hydrogen and oxygen were determined by elemental analysis and stable isotope mass spectrometer. Combined with Duncan multiple comparative analysis, fisher discriminant analysis and sequential discriminant analysis, a origin discriminant model for the main root of three-year-old spring P. notoginseng was established for 3 production areas of P. notoginseng. The geographical climate and environment of three production areas of P. notoginseng are obviously different. From Guangxi Baise-Yunnan Wenshan-Yunnan new cultivating regions, the longitude, average annual temperature and annual precipitation gradually decrease, and the elevation and latitude are increasing. The results of multiple comparative analysis showed that there were significant or very signi-ficant differences in the δ~(13)C,δ~(15)N,δ~2H,δ~(18)O of the main roots of P. notoginseng in three regions. The results of fisher's discriminant analysis and sequential discriminant analysis showed that the correct discriminant rates of the main roots of P. notoginseng for three regions were 80.05%,76.47% and 90.91%, respectively, based on four stable isotope ratios, with an average of 84.09%. Using stable isotope fingerprint and chemometrics method, we can distinguish the origin of the main raw materials and products of P. notoginseng.

Saurida elongata , a warm-water offshore benthic fish, is one of the dominant species in Haizhou Bay and plays an important role in the food web. Based on samples collected from bottom trawl surveys in Haizhou Bay, we examined the feeding habits of Saurida elongata based on both stomach content and stable isotope analyses. The results showed that the main prey species of Saurida elongata were Metapenaeopsis dalei , Loligo spp., Cryptocentrus filifer , Engraulis japonicus , Chaeturichthys hexanema , Apogonichthys lineatus , Syngnathus acus and Callionymus beniteguri . The range of δ 13 C value was -19.39‰ to -16.23‰, with an average value of (-18.01±0.85)‰. There was no correlation between body length and δ 13 C values. The value of δ 15 N ranged from 9.56‰ to 13.36‰, with an average value of (11.77±0.86)‰, which was significantly positively correlated with body length. There was substantial difference in the contribution of food organism among diffe-rent body length groups. With the increases of body size, predation ability and morphology of feeding organs gradually improved, and the proportion of prey organisms changed, which might be the main reason for the ontogenetic variation in feeding habits. This study could contribute to understand the feeding ecology of snake mullet in Haizhou Bay and provide basic information for the nutritional dynamics of the Haizhou Bay food web.

Objective: The method for analyzing of 20 polychlorinated biphenyls(PCBs) in water by stable isotope internal standard-automatic solid-phase extraction membrane(auto SPEM) coupled to gas chromatography-mass spectrometer(GC-MS) was established, and applied to the analysis of trace PCBs in water samples., Methods: The sample backgrounds of bottled mineral water production in Fuzhou(groundwater), inland water in Fuzhou university city(surface water), tap water(pipe tip water) and stream water in Xiyuan Gong(water source of life) were analyzed by GC-MS. Surrogate solution(SS)internal standards including ~(13)C_(12 )PCBs stable isotope was used for quantification. The method was confirmed by calculating recovery rate(RR) and relative standard deviation(RSD) of spiked water samples(20, 40 and 80 ng/L, n=7). And recovery rates of SS were used to evaluate the effect of the pretreatment. And the method was used to determine PCBs of a total of 17 cross-sectiona river water in minjiang river tributaries upstream to the downstream estuary., Results: The method detection limits(MDL) were 1. 9-6. 6 ng/L, and RRs were 70. 9%-127%, and RSDs were 0. 5%-13%. The RRs of SS were 40%-90%. Positive sample was not detected., Conclusion: The method of auto SPEM is less solvent, more automatic than traditional manual SPE. And the method is more accurate and reliable by stable isotope internal standard coupled to GC-MS. Therefore, it is useful for the trace PCBs determination of waters.

Caohai Plateau Wetland is a National Nature Reserve. The characteristics of stable mercury isotopic compositions in the food web were studied by comprehensively analyzing the concentrations of Hg species (MeHg, THg), δ 13 C, and δ 15 N, and the isotopic compositions of Hg in different aquatic organisms. The main results are as follows:all samples of the food web show mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) and a negative δ 202 Hg(-0.93‰±1.32‰, n =14)and positive △ 199 Hg(0.79‰±0.76‰, n =14). The δ 199 Hg values are significantly positively correlated with δ 15 N ( r N=-1.88‰), indicating that the bioaccumulation of mercury leads to an enrichment with heavier isotopes. The △ P <0.05) and the δ 202 Hg values also exhibit a positive correlation with δ 15 N, except for Myriophyllum spicatum ( δ 15 N=-1.88‰), indicating that the bioaccumulation of mercury leads to an enrichment with heavier isotopes. The △ 199 Hg values increase with δ 15 N( r =0.67, P <0.05). Nevertheless, the △ 199 Hg values correlate with% MeHg ( r =0.58, P <0.05), indicating that the increase of the MIF level in the samples with the food web might be related to% MeHg.

Fine particulate matters (PMZ2.5) collected in Beijing during a period from September 2005 to May 2006 were studied. Sequential extraction procedures were applied to divide the total lead into three fractions, i.e. water soluble, liposoluble and insoluble lead. Lead concentrations and their isotopes in each fraction were then determined by inductively coupled plasma mass spectrometry (ICP-MS). Lead standard reference GBW 09133 was used to investigate the accuracy of lead concentration determination and SRM 981 was used to correct the mass discrimination and instrumental drift. The obtained results showed that the analytical precision of lead isotope ratios for SRM 981 of seven repeat measurements at lead concentration of 10 ng x mL(-1) came to about 0.34, 0.27 and 0.24 percent for the 206 Pb/204 Pb, 206Pb/207 Pb and 206Pb/208 Pb ratios, respectively. In Beijing, the mass concentrations for PM2.5 and lead of ambient air were 125.556 and 0.5415 microg x m(-3) respectively for winter 2005, and 201.6 and 0.475 microg x m(-3) respectively for spring 2006 on average, resembling those published results. It was indicated that the lead in the PM2.5 existed mainly in insoluble form, which accounted for 78.99%, while water soluble lead and liposoluble lead amount were 20.69% and 0.32%, respectively. The mean values of 206Pb/207Pb ratio for water soluble species and insoluble species were 1.152 6 +/- 0.009 3 and 1.219 3 +/- 0.009 1 respectively, with a significant difference (Student's test; p < 0.01) statically. By comparing 206Pb/207Pb ratios between biological specimen and ambient air samples, the 206Pb/207Pb ratios in water soluble fraction coincided very well with those in adult blood, therefore, water soluble lead but not insoluble lead in PM2.5 may be the potential source of adults blood lead in Beijing. More attention should be paid to the effect of soluble lead in fine particle matters on human health.