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Rainwater samples were collected in the summer on "Shiyan 3" during the 2012 South China Sea Sectional Scientific Survey. The concentrations of anion and cation, and pH in precipitation were determined and backward trajectories of air mass were simulated to analyze the chemical characteristics of ions and examine the source of ions. The results indicated that the mean pH value of precipitation was 6.3, with 5.6 of minimal value in summer in South China Sea. The order of anion and cation abundance was Cl(-)S04(2-)NO3(-) and Na(+)Mg(2+)Ca(2+)K(+). Cl(-) was the major anion and Na(+) was the major cation, with concentrations of 2 637.5 microeq x L(-1) and 2095.5 microeq x L(-1), respectively, showing that they were the characteristics of marine atmospheric precipitation. There was a good linear relationship between each pair of 7 ions, with correlation coefficient above 0.9, suggesting that they may have a common source. However, the correlation coefficients were lower between NO3(-) and other ions than the others, suggesting that NO3(-) had more complex sources. The concentrations of Ca(2+) and K(+) in precipitation may be related to coral environment in South China Sea. The backward trajectories in 6 stations showed that the air mass was from south and southwest of South China Sea, without passing through above the continent. These results suggested that precipitation affected by human ion source can be ignored in summer in South China Sea.

Pollution characteristics of heavy metals in the farmland soil nearby a metal smelter were studied. Soil samples were collected and the contents of elements V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, Mo, Cd, Sn, Sb, Pb, U and As in the bulk samples of soil profiles were measured, with the objectives to identify the pollution status and pollution characteristics of the farmland soil that were suffered from smelter effluents flooding, an acute pollution accident. The results indicate that the concentrations of heavy metals Zn, Mn, As, Pb, Cd,Sb in the soil were 113.28-212.22, 251.67-2 429.29, 34.44-130.28, 50.63-544.74, 63.44-317.33, 39.41-551.17 mg/kg, respectively, higher than the background level. These polluted soils not only have high concentrations of As, but also of the Zn, Mn, Pb, Cd and Sb. According to correlation analysis, pollution level is closely with local nonferrous metal exploitation, and principal pollutants have the same source. Some trace metals, such as Zn, Cr, Cd, show increasing concentration first and then decreasing trend in the soil profile. Soil acidification appears in the topsoil. This study has characterized the metal pollution in soils flooded by sudden smelting effluents spilling, and provided a theory base for pollution treatment.

Sequential extraction methods for soil sulfur were used to determine delta34 S ratios and sulfur contents of total sulfur, organic sulfur, SO4(21) and FeS2 in slope soils of karst areas. In general, FeS2 has the lowest delta34 S ratios, ranging from -6.86% per hundred to -4.229% per hundred, followed in ascending order by SO4(2-) (-2.64% per hundred - -1.34% per hundred), total sulfur (-3.25% per hundred - -1.03% per hundred) and organic sulfur (-1.63% per hundred -0.50% per hundred) in surface soils of profiles, and delta34 S ratios in different sulfur forms all show increasing trend with profiles deepening. Covariations of delta34 S ratios of SO4(2-) and FeS2 with increasing depth are related to SO4(2-) dissimilatory reduction, while the increase in parallel of delta34 S ratios of total sulfur and organic sulfur could be resulted from organic sulfur cycling. delta34 S ratios have been extensively used to indicate sulfur sources, moreover, SO4(2-) dissimilatory reduction and organic sulfur mineralization result in significant sulfur isotopic fractionation, and sulfides oxidation and SO4(2-) assimilation have no isotopic fractionation occurred, the vertical variations of delta34 S ratios in different sulfur forms can therefore be good records for depth-dependant sulfur cycling processes. Furthermore, by comparing depth distributions of sulfur contents and delta34 S ratios in different sulfur forms, it is easily to discuss the migration of SO4(-1) and organic sulfur fractions in soil profiles.

Concentrations of CO2, N2O and CH4 of soil profile in Karst Stone Desertification Areas were measured monthly from June of 2006 to May of 2007. The results indicated that the concentrations of CO2, N2O and CH4 varied from 530.2 to 31512.6, 0.27 to 0.67 and 0.1 to 3.5 microL x L(-1). On the whole, with the increase of soil depth, the concentrations of CO2 and N2O increased, while CH4 decreased. However, in the cold and wet October, November and January, the concentrations of CO2 and N2O decreased with the depth below 15 cm. In contrast, CHR4 had the inverse trend. Soil temperature and moisture were the main factors which had impacts on the temporal and spatial variations of C2O, N2O and CH4 concentrations in soil profile, but the influence impacts were different. The correlation analysis showed that there was positive correlation between CO2 and N2O (r 0.780-0.894, p0.05-0.01), while correlation degree was controlled by environmental factors in different months. CH4 concentrations in soil had significantly negative correlation with CO2 concentrations (r = 330, p0.01), but correlated with N2O concentrations just in moisture months (r - 0.829- - 0.956, p0.05-0.01).

Water samples along water column in the front of dams and samples at 0.5 m below surface water from tributary rivers were collected in July and October, 2007. The water chemistry, concentrations of dissolve inorganic carbon and its carbon isotopic compositions were determined, in order to investigate the geochemical behavior of carbon in the Maotiao River. This study aimed to understand the variations of the concentrations of dissolved inorganic carbon (DIC) and delta13 C(DIC) during its transport along the cascade reservoirs and river system. The results showed that DIC concentrations in summer were lower than that in autumn. In summer, the DIC concentrations were 1.35-2.84 mmol/L, with an average value of 2.12 mmol/L; and in autumn they fell into 2.03-3.98 mmol/L, with an average value of 2.67 mmol/L. The delta13 CD1 in surface water along Maotiao River ranged from -10.3% per hundred to -5.1% per hundred in summer, with a value of -8.6% per hundred in average, and in autumn, delta3 C(DIC) became more negative, and had a range from -13.0% per hundred to -6.9% per hundred, with an average value of -9.0% per hundred. Generally, DIC in surface water showed a trend to decrease from the upper reaches to lower reaches along Maotiao River, and t3 Cc1 gradually becam me more negative downstream. On the water column, DIC concentrations were higher in hypolimnion, while a delta13 C(DIC) had a reverse trend with higher values occurred in epilimnion. The results indicated that the hydrochemistry of river could be significantly changed by river damming processes. As for carbon, reservoir should be an important place for the transformation among the different carbon species.

The characteristics of chloramphenicol and tetracyclines in municipal sewage and Naming River of Guiyang City were studied, using solid-phase extraction with high-performance liquid chromatography-UV detection. The average concentration of chloramphenicol, oxytetracycline, tetracycline and chlortetracycline in municipal sewage is 27.0, 2.3, 11.0 and 1.1 microg x L(-1) at northern outfall, and 21.2, 2.1, 9.5 and 0.5 microg x L(-1) at southern outfall. Nanming River is influenced by many antibiotic sources which include agriculture land, surface waste and municipal sewage, and the municipal sewage is the most important one. The concentration of chloramphenicol, oxytetracycline and tetracycline in river water ranges from 2.1 to 19.0 microg x L(-1), ND to 3.0 microg x L(-1) and 0.8 to 6.8 microg x L(-1) in winter, and 0.2 to 1.3 microg x L(-1), ND to 0.03 microg x L(-1), 0.2 to 0.3 microg x L(-1) in summer. Chlortetracycline was only detected in winter with the concentration range of 0.09 to 0.14 microg x L(-1). The average concentration of the four compounds in sediment is 147.6, 76.6, 99.2 and 1.6 microg x kg(-1) in winter, 195.8, 89.1, 34.4 and 9.0 microg x kg(-1) in summer, respectively. The antibiotics concentration of both river water and sewage shows a seasonal variation.

We investigated the carbon (C) and nitrogen (N) concentrations and isotopic signatures (delta 13C and delta15 N) in epilithic mosses collected from urban sites to rural sites along four directions at Guiyang area. Mosses C (34.47%-52.76%) decreased significantly with distance from urban to rural area and strongly correlated with tissue N (0.85%-2.97%), showing atmospheric N deposition has positive effect on C assimilation of epilithic mosses, higher atmospheric N/NHx deposition at urban area has improved the photosynthesis and C fixation of mosses near urban, which also caused greater 13C discrimination for urban mosses. Mosses delta 13C signatures (-30.69% per hundred - -26.96% per hundred) got less negative with distance from urban to rural area, which was also related to the anthropogenic CO2 emissions in the city, and these 12C-enriched CO2 sources would lead to more negative mosses delta 13C through enhancing the atmospheric CO2 concentration in urban area. Moreover, according to the characteristics of mosses C and delta 13C variations with distance, it is estimated that the influences of urban anthropogenic CO2 sources on plants was mainly within 20 km from city center. This study mainly focused on the factors regulating tissue C and delta 13C of mosses in city area and the interaction between C and N in mosses, the responses of mosses C and delta 13C to urban CO2 emission and atmospheric N deposition have been revealed, which could provide new geochemical evidences for the control of city atmospheric pollution and the protection of ecosystems around city.

Tissue N concentration and delta15 N signature in epilithic mosses were investigated along 4 directions from urban area to rural area at Guiyang city. Mosses N concentration ranged from 0.85% to 2.97% and showed significant decrease from urban area (2.24% +/- 0.32%) to suburb (1.27% +/- 0.13%), reflecting the level of atmospheric N deposition decreased away from urban. While slightly higher tissue N re-emerged at rural area beyond 25km (mean = 1.33%-1.75%), suggesting increased N deposition occurred in the rural area. Mosses delta15 N values varied from - 12.50 per thousand to - 1.39 per thousand characterized with getting less negative from urban to rural area. More negative delta15 N signatures of urban mosses (mean= - 8.87 per thousand(-) - 8.59 per thousand) mainly indicated the extensive NH3 sources released from excretory wastes and sewage, while mosses growing at farther suburb or rural area had less depleted delta15 N values (mean = - 3.83 per thousand(-) - 2.48 per thousand), indicating the large sources of agricultural NH3 emission connected with fertilizer application. Moreover, the pattern of mosses delta15 N variation in this study was opposite to areas where N deposition was dominated by oxidized form N (NO(x)) with generally positive mosses delta15 N. Accordingly, we concluded that reduced NH, was the dominant N form in atmospheric deposition at Guiyang area, which would be of great value for understanding the spatial variation and sources of atmospheric N deposition.

The partial pressure of carbon dioxide p(CO2) in the surface water of the two karst eutrophic reservoirs, Hongfeng and Baihua Lakes near Guiyang city, Ghuizhou Province, China has been studied for one year. The factors regulating the seasonal variability of p(CO2) in the two reservoirs have been analyzed. Unlike the reservoirs in boreal temperate regions, the p (CO2) in the two reservoirs has significant seasonal changes: CO2 was unsaturated during summer, but supersaturated at other seasons. According to the correlation analysis, there is a negative relationship between p (CO2) and Chla in the two reservoirs, due to the production of the phytoplankton and the respiration of the organic matter by the bacteria, which are also the main factors regulating the p(CO2). The negative relationship between temperature and p(CO2) is considered to be due to the effect of temperature on the growth of the phytoplankton. Precipitation leads to the input of the nutriments into the reservoirs, and hence precipitation is negatively related to p(CO2). The relationships between NO3-, NO2- and p(CO2) are ascribed to the absorption of phytoplankton, and the degradation of the organic matter nitrification. The relationship between SiO3(2-) and p(CO2) is due to the absorption of phytoplankton and the precipitation. The differences of the relationship between p(CO2) and DOC in the studied two lakes possibly lie in the variations of their sources.

Four soil profile samples were collected in the middle of de-farming and wasteland billabong and around slopes, located at typical karst district of Guizhou province. Soil organic matter (SOC) content and delta Corg, were determined. SOC content ranged from 6.0 mg x kg(-1) to 92.3 mg x kg(-1), and decreased with depth at slope soil profiles. The range of value was bigger than that at billabong soil profile (6.3-26.7 mg x kg(-1)). The value of detla13 Corg, at slope profiles was between - 25.103% per hundred and - 23.666% per hundred, but variation direction of three slope soil profiles was different. The value of delta 13Corg, in billabong soil profile was between - 23.495% per hundred and - 20.809% per hundred, and increased with depth. The correlation between delta13 Csoc and C4-C,C3-C was significant (R = 0.884, n=7), influenced by new C3-C.

Variations of delta 13C(org) and delta 15N values, C/N ratios, TOC and TN contents in Chaohu Lake sediments reflect the sources of organic matter in lake sediments, evolution of lake productivity and the eutrophic status in Chaohu Lake during last 100 years. Our results suggest that the sedimentary organic matter was derived mainly from aquatic algae and partly from land matter. However, the input of the pollutants from city and agriculture into the lake could not be neglected. Two stages can be found in the sediments cores according to the profiles of delta 13C(org), delta 15N values, TOC and TN contents. Below 10cm, delta 13C(org) values vary between - 21.74 per thousand and - 19.34 per thousand. Nitrogen fixing and non-nitrogen fixing phytoplankton coexist together. Two cores show different nutrition processes. Above 10cm, in both profiles, the values of delta 13C(org) start to decrease sharply, but delta 15N, TOC and TN increase. The construction of Chaohu Gate leads to the enhancement of lake productivity and development of eutrophication.

Distributions of seven PCBs (polychlorinated biphenyls) congeners and 13 OCPs (organochlorinated pesticides) were investigated in paddy soil section in Hongfeng reservoir area. The results showed that DDTs and its metabolized compounds, isomer of HCHs, Endrin, heptachlor, PCB 28 and PCB 52 were detected in all soil samples. Compared to the polluted area, the concentrations of PCBs were lower in study area, while the compositions of organic pollutants in soil samples were similar. The dominant compositions of PCBs and OCPs were tri-, tetra-, and penta-chlorinated PCB congeners and DDTs respectively. The proportion of tri-, tetra-and penta-CB was 89 percent. The contents of DDTs were between 4.7 ng/g and 42.6 ng/g and p, p'-DDE, p, p'-DDT were the major isomers. The ratios of DDT/ (DDD + DDE) showed that the rate of DDTs degradation and environment status were different. The range of alpha-HCH/gamma-HCH was 0.28 - 0.90, indicating that HCHs had stayed for long time in environment. By photolysis and microbial, the proportion of the HCHs isomers had changed in Hongfeng reservoir area. SigmaTEQ of PCB118 and PCB180 were 0.06 - 0.51 pg/g.

Thirteen weathering profiles of typical rocks such as limestone, dolomitic limestone, dolomite, sillcalite, black shale and purple sandrock from Wujiang catchments were selected for discussing enrichment and release behavior of uranium (U) during rock weathering, and studying its impact on riverine U distribution in the catchments during weathering of these rocks with methods of correlation analysis and mass balance calculation. The purpose of this study is to improve our understanding on biogechemical cycling of U and set a basis for catchment protection against U pollution. The results show that the enrichment extent of U in soils from the Wujiang catchments is usually higher than that of upper continental crust (UCC), China soil (CS) and world soil (WS). The ability of enrichment and release of U is partly controlled by content of U in bedrocks, contents and adsorption ability of clay minerals and Fe-oxides/hydroxides in weathering profiles. Our study also reveals that release of U mainly from weathering of limestone and partly from weathering of dolomite and clastic rocks exerts an important control on riverine U distribution.

Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) are rarely measured together when studying dissolved organic matter (DOM) in lake water. DOC and DON concentrations were measured for a Karst plateau lake--Hongfeng Lake water for nearly two years. Profile characteristics and seasonal variation of dissolved organic matter were studied, and influencing factors were discussed. The results indicate that DOC concentration ranges from 1.60 mg x L(-1) to 3.08 mg x L(-1), DON ranges from 0.10 mg x L(-1) to 0.37 mg x L(-1) during studying period. DOC and DON concentrations change little from upper layer water to bottom during mixed periods, but show a general tendency for an upward increase during stratification periods. DOC concentration in the surface layer water (0-2 meters or 3 meters) of Hongfeng Lake is greatest from late spring to early summer or in summer, DON concentration is a little higher from late spring to early summer. Comparing the seasonal variation trend of DOC with that of chla and rainfall we draw a conclusion that the bioactivity of algae and DOM input from the watershed directly result in the seasonal variation mode of DOM in surface layer water. The C/N ratio of DOM generally increases with the increase of depth, but this trend changes at HF-S site in summer. At the depth of 12m, DOC and DON concentrations increase with the increase of depth; the C/N ratio of DOM decreases from 18.1 at the depth of 12 m to 14.9 at the depth of 14 m, and decreases continually with the increase of depth. A possible cause is the decomposition of POM, which forms an autochthonous source of DOM.

Since the Aha Lake, located in Guizhou Province, China, was enlarged in 1982, a great amount of iron and manganese were input into it owing to the uninterrupted pollution from acidic mining drainage of coal mines (AMD). The results show that dissolved Fe2+ and Mn2+, mainly from AMD, were markedly separated each other as water flowed from inlet to downstream. The Aha lake water, with the average pH equal to 7.28, was not acidified just because the lake is developed in the karst area and people continuously put lime in it in recent years. Fe2 + and Mn2 + deposit in the different locations in lake because of the difference of oxidizing rate between Fe2+ and Mn2+ during water flowing from inlet to downstream, and also forming the horizontal separation along the lake water flowing direction. Manganese tends to be obviously enriched in the upper of sediment in lake's deep locations, presenting the remarkable separation with iron in the vertical section. After normalized by Ti content in sediment, it is obvious that the remarkable separation between iron and manganese corresponds with the enlargement of lake in 1982. As shown in the concentration profile of pore water in sediment, iron was remobilized weakly while manganese reduction mainly happens in the upper of sediment, indicating its strong remobilization. Based on the studies, a mechanism for environment and fractionation of Fe2+ /Mn2 + during water flowing in the lake was also demonstrated.

With the development of fluorescence technique, three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was widely applied to characterize the nature of dissolved organic matter (DOM) in natural waters since the last decade. 3DEEM and fluorescence quenching titration were used to study the interaction between Hg(II) and DOM. The results show that a general decrease in intensity for individual peak A, B and C was found as concentrations of Hg(II) increased. pH is the main parameter that strongly influences the Hg(II)-DOM complexation. The addition of Cl- ion to the Hg(II)-DOM system caused an increase in fluorescence intensity. The results also show that the addition of Ca(II) solution strongly enhanced the fluorescence intensity for humic-like fluorescence, while the protein-like fluorescence only slightly enhanced. On the contrary, no fluorescence enhancement was found in the Hg(II)-DOM system after the addition of Mg(II) ion. A decrease in fluorescence emission intensity was found after the addition of Cu(II) ion to the Hg(II)-DOM solution.