Mechanism of a Herbal Formula Associated with Prognosis and Immune Infiltration in LIHC: Transcriptomics Analysis and Molecular Dynamics Simulations.

Background: The aim of this study is to explore the interactions between effective monomers of herbal formulas and their therapeutic targets using systems biology approaches which may be a promising approach to unraveling their underlying mechanisms. Shentao Ruangan decoction (STRGD), which has been experimentally, clinically demonstrated to be effective in treating liver hepatocellular carcinoma (LIHC), was selected. Methods: Bioactive ingredients and drug targets of STRGD were retrieved from the traditional Chinese medicine systems pharmacology database and analysis platform and BATMAN-TCM databases. LIHC-related differentially expressed genes (DEGs) and key modules were identified by a weighted gene coexpression network analysis using The Cancer Genome Atlas data. The Kaplan-Meier analysis was used to investigate the relationship between STRGD tumor targets and patients survival. The CIBERSORT deconvolution algorithm was used to analyze the correlation between STRGD tumor targets and infiltrating immune cells. Enrichment analysis was used to analyze biological functions. Interactions between STRGD compounds and LIHC-immune-related genes were investigated using molecular docking and MDS. Results: We identified 24 STRGD tumor targets, which were found to be correlated with survival and the level of immune cell infiltration in LIHC patients. Immune infiltration, gene set enrichment, and Kyoto Encyclopedia of Genes and Genomes analyses highlighted the roles of T and B cell subsets, which were both related to activator protein 1 (AP1), in STRGD action. Docking studies and HPLC indicated that tanshinone IIA is the main compound of STRGD in LIHC treatment, and MDS showed that the potential LIHC-immune-related targets 1FOS and 1JUN firmly bind to tanshinone IIA. Conclusions: The mechanisms of STRGD in improving the immune and survival status of LIHC patients include interactions between STRGD compounds and LIHC-immune-related targets. The findings of this study can guide research studies on the potential usefulness of tanshinone IIA in the development of drugs targeting 1JUN and 1FOS for the treatment of LIHC.

Targets and Potential Mechanism of Scutellaria baicalensis in Treatment of Primary Hepatocellular Carcinoma Based on Bioinformatics Analysis.

OBJECTIVE: To analyze the target and potential mechanism of Scutellaria baicalensis (SB) in the treatment of HCC based on bioinformatics, so as to provide suggestions for the diagnosis, treatment, and drug development of hepatocellular carcinoma (HCC). METHODS: The regulated gene targets of SB were screened by gene expression pattern clustering and differential analysis of gene expression data of HepG2 cells treated with SB at 0 h, 1 h, 3 h, 6 h, 12 h, and 24 h. The module genes related to HCC were identified by the weighted gene coexpression network analysis (WGCNA). KEGG and GO enrichment were used to analyze the molecular function and structure of the module, and GSEA was used to evaluate the different functional pathways between normal people and patients with HCC. Then, the module gene was used for univariate Cox proportional hazard analysis and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis to build a prognostic model. The protein-protein interaction network (PPI) was used to analyze the core genes regulated by SB (CGRSB) of the module, and the survival curve revealed the CGRSB impact on patient survival. The CIBERSORT algorithm combined with correlation analysis to explore the relationship between CGRSB and immune infiltration. Finally, the single-cell sequencing technique was used to analyze the distribution of CGRSB at the cellular level. RESULTS: SB could regulate 903 genes, of which 234 were related to the occurrence of HCC. The prognosis model constructed by these genes has a good effect in evaluating the survival of patients. KEGG and GO enrichment analysis showed that the regulation of SB on HCC mainly focused on some cell proliferation, apoptosis, and immune-related functions. GSEA enrichment analysis showed that these functions are related to the occurrence of HCC. A total of 24 CGRSB were obtained after screening, of which 13 were significantly related to survival, and most of them were unfavorable factors for patient survival. The correlation analysis of gene expression showed that most of CGRSB was significantly correlated with T cells, macrophages, and other functions. The results of single-cell analysis showed that the distribution of CGRSB in macrophages was the most. CONCLUSION: SB has high credibility in the treatment of HCC, such as CDK2, AURKB, RRM2, CENPE, ESR1, and PRIM2. These targets can be used as potential biomarkers for clinical diagnosis. The research also shows that the p53 signal pathway, MAPK signal pathway, apoptosis pathway, T cell receptor pathway, and macrophage-mediated tumor immunity play the most important role in the mechanism of SB in treating HCC.

Effect of Berberine on Hyperuricemia and Kidney Injury: A Network Pharmacology Analysis and Experimental Validation in a Mouse Model.

PURPOSE: Berberine (BBR) is an active component of Phellodendri Cortex (PC), which is a traditional Chinese medicine that has been prescribed clinically for hyperuricemia (HUA) for hundreds of years. Many studies reported the anti-inflammatory and nephroprotective properties of BBR and PC; however, the therapeutic effects of BBR on HUA have not been explored. This study aims to investigate the efficacy and mechanism of BBR for treating HUA. METHODS: The mechanism of BBR in the treatment of HUA were predicted by network pharmacology. A mouse model of HUA established by potassium oxonate and hypoxanthine was used to verify the prediction. The levels of serum uric acid (UA), urea nitrogen (BUN) and creatinine (CRE) were determined by biochemical test kits. Hematoxylin and eosin staining of kidney tissues was used to observe the kidney damage. ELISA kits were applied to detect the levels of interleukin (IL)-1ß and IL-18 in serum and kidney tissues. Quantitative real-time PCR and Western blotting were adopted to analyze the expression of NLRP3, ASC, Caspase1, IL-1ß and URAT1. The expressions of URAT1 in the kidney tubules were visualized by immunohistochemical staining. Molecular docking was used to assess the interaction between URAT1 and BBR. RESULTS: The network pharmacology screened out 82 genes and several inflammation-related signaling pathways related to the anti-hyperuricemia effect of BBR. In the in vivo experiment, BBR substantially decreased the level of UA, BUN and CRE, and alleviated the kidney damage in mice with HUA. BBR reduced IL-1ß and IL-18, and downregulated expressions of NLRP3, ASC, Caspase1 and IL-1ß. BBR also inhibited expression of URAT1 and exhibited strong affinity with this target in silico docking. CONCLUSION: BBR exerts anti-HUA and nephroprotective effects via inhibiting activation of NLRP3 inflammasome and correcting the aberrant expression of URAT1 in kidney. BBR might be a novel therapeutic agent for treating HUA.

Synchronization of dehydration and phosphorous immobilization for river sediment by calcified polyferric sulfate pretreatment.

Disposal of dredged river sediment requires decreases in both water content for reduction in disposal area, and the amount of eutrophication pollutants at risking of leaching. The effects of CaCl2, polyferric sulfate (PFS) and calcified polyferric sulfate (CaPFS) on dewatering and phosphorus immobilization were examined. Upon CaPFS dosage of 1.88 mg Ca + Fe kg-1 raw sediment (RS) the moisture content of the sediment was 41.1 wt% after pressure filtration, with filtrate dissolved inorganic phosphorus (DIP) of 6.1 mg L-1; better outcomes than for equivalent dosages of CaCl2 or PFS. On CaPFS dosage of 4.98 mg Ca + Fe kg-1 RS, DIP in the filtrate was <0.5 mg L-1. Dosages of CaCl2 and PFS required to achieve <0.5 mg L-1 DIP were 6.79 mg Ca kg-1 RS and 5.64 mg Fe kg-1 RS. CaPFS aids particle surface charge neutralization and sweep flocculation by polymeric iron, improving dehydration efficiency. Synergistic effects of aqueous Ca and Fe promote P stability reducing DIP mobility. For treatment of 10000 m3 of this dredged sediment, CaPFS has the potential to reduce the discharge of eutrophicated water by 74 ± 6% compared with PAC + PAM conditioning, demonstrating the promising application of CaPFS conditioning.

The influence of extensive green roofs on rainwater runoff quality: a field-scale study in southwest China.

Green roofs of young age (≤ 5 years old) have boomed in China since the Sponge City Construction initiative was implemented. To use green roofs for better urban stormwater management, it is necessary to investigate the runoff quality of field-scale young green roofs as well as to examine common plant-media combination in green roof projects of China. The influence of two Sedum-vegetated extensive green roofs of different designs at the early stage of operation on runoff water quality was investigated by a field-scale study in Chengdu, southwest China. The water quality parameters of pH, suspended solids (SS), chemical oxygen demand (COD), total phosphorus (TP), and total nitrogen (TN) of rainwater (that is, input water for roofs), runoff from the two green roofs, and runoff from a conventional concrete control roof were compared. The results indicate that both green roofs mainly act as pollutant sources with greater concentrations of SS, COD, and TP when compared with rainwater quality. When compared with runoff quality from the control roof, greater TP concentrations in runoff from one green roof with commercially available substrate were observed. Attention should be paid to TP leaching in runoff for retrofitted green roofs with imported commercial substrates in that region. Adoption of pre-cultivated S. lineare mats of low fertility and localized soils may reduce nutrient leaching in green roof runoff. A nitrogen-rich substrate is not recommended for a plant community of a single species. Investigation of the effect of green roofs on water quality involving various pollutants in the long run is recommended.

[Spatial Distribution Characteristics of Nutrients and Chlorophyll A in the Lancang River Basin Under Cascade Reservoirs].

Construction of cascade reservoirs in Lancang River had a certain influence on the ecological water environment of the basin, dividing the water into natural reaches and reservoir reaches. To explore the impact of the cascade reservoirs on the ecological environment, the nutrient and the chlorophyll a distribution data were measured in the natural reaches, reservoir reaches, and tributaries in June 2017. The results showed that the TN ranged from 0.37 to 1.22 mg·L-1, with an average of 0.70 mg·L-1, and the TP ranged from 0.01 to 0.19 mg·L-1, with an average of 0.04 mg·L-1. One-way ANOVA analysis showed significant spatial differences in the TN, with the TN concentration following the order tributaries > reservior reaches > natural reaches. However, the TP concentration did not show a significant trend. The chlorophyll a concentration varied from 2.6 to 10.2 µg·L-1, with a mean of 5.8 µg·L-1. Pearson correlation analysis showed significant relationships between the chlorophyll a concentration and the TP, water temperature, and Zeu/Zmix. The relationship between chlorophyll a and Zeu/Zmix was particularly significant, which indicated the Zeu/Zmix caused by thermal stratification may be the key factor influencing the growth of phytoplankton.

[Dynamic Replenishment Process of Nutrients in Tributary of Channel Reservoir].

The process of phytoplankton succession and change in primary productivity are directly determined by the seasonal variations in nutrients in tributary bays of channel reservoirs. This study aimed at analyzing the effects of the main nutrient sources on seasonal distribution of nutrients in Xiangxi Bay based on the field data collected in 2010 and 2011. The tracing inorganic ions were Cl- and Na+ that showed significant differences (P<0.01) between the mainstream and the tributary. The nutrient contribution rates of different sources were calculated by the binary linear model. The results showed that the nutrient contribution rate of the mainstream was more than 75% during the dry season and the impoundment period. The intrusion of the mainstream was the main source of nutrients in Xiangxi Bay. The difference in the contribution rates between the mainstream and the upstream decreased during the pre-flood drawdown period and the flood season. The concentration of total phosphorus was higher in the upstream, while the concentration of total nitrogen was higher in the mainstream. The patterns of density currents were different and the nutrient contribution rates of different sources changed accordingly. Therefore, the nutrients of Xiangxi Bay changed regularly in different operation periods of the Three Gorges Reservoir.

Stable isotopes in water indicate sources of nutrients that drive algal blooms in the tributary bay of a subtropical reservoir.

Eutrophication has become a severe environmental problem in some tributaries of the Three Gorges Reservoir (TGR) in China. A two-year field investigation of nutrients, oxygen stable isotopes (δ18O), and hydrogen stable isotopes (δD) was performed from January 2010 to December 2011 to determine the sources of nutrients in Xiangxi Bay (XXB). The results showed that nitrogen, phosphorus and silicon varied seasonally depending on hydrodynamic changes. The bottom-layer intrusive density current decreased nitrogen and silicon concentrations and increase phosphorus concentrations in XXB, while the middle-layer intrusive density current increased nitrogen and silicon concentrations and decrease phosphorus concentrations. The differences in δ18O and δD among the Yangtze River (YR), XXB and the region upstream of XXB were significant, and according to the tracer method, the estimated contribution ratios of nitrogen, phosphorus and silicon from the YR to XXB were much larger than those from the region upstream of XXB. These findings suggest that water quality in the TGR can be improved by reducing the pollution load throughout the upstream basin of the YR but not through decentralized efforts in only one or two tributary basins.

[Succession Pattern of Phytoplankton of Daning River in the Three Gorges Reservoir and Its Driving Factors].

To elucidate succession pattern of phytoplankton in the Daning River and its driving factors, multivariate statistical analysis was conducted. By using the monitoring data in different seasons of Daning river during April 2012 to January 2013, this paper analyzed the succession pattern of phytoplankton in the Daning River and its driving factors in typical tributaries of river-style reservoirs. According to the characteristics of water level, the operational period of the TGR was classified into following four stages:stage Ⅰ (pre-November-April), stage Ⅱ (May-July), stage Ⅲ (July-September) and stage Ⅳ (September-November). ① The results indicated that the values of Chlorophyll-a concentrations and algal density showed similar seasonal variations, with the highest values occurring in stage Ⅲ, followed by stages Ⅳ, Ⅱ and Ⅰ. Succession of C-R-S growth strategies was the same generally:CR-R type dominated in stage Ⅰ, CS, CR/CS and R-CR dominated in stage Ⅱ, Ⅲ and Ⅳ, respectively. ② The mean values of Margalef index and Pielou index in stage Ⅳ and Ⅲ were significantly greater than those in stage Ⅱ and Ⅰ; the value of Shannon-waver index showed that the highest value in stage Ⅲ, followed in a descending order by stage Ⅰ,Ⅱ and Ⅳ; the successional rate had the highest value in stage Ⅳ, followed in descending order by stage Ⅲ, Ⅰ and Ⅱ. ③ The results of Correlation analysis suggested that no significant relationships were observed between the environmental parameters and phytoplankton abundance in stage Ⅰ. The results indicated that relative water column stability(RWCS), index of feasible energy for phytoplankton (Et) and index of feasible energy (Ef*) were key regulatory factors for phytoplankton community in stage Ⅰ. The results indicated that Et, Ef* and total phosphorus (TP) were key regulatory factors for phytoplankton abundance in stage Ⅱ. The results of the redundancy analysis (RDA) suggested that RWCS, TP and the ratio of euphotic depth[Deu(λPAR)] to mixing depth (Dmix)[Deu(λPAR)/Dmix] were key regulatory factors for phytoplankton community composition in stage Ⅱ. The results indicated that Ef* and TP were key regulatory factors for phytoplankton abundance in stage Ⅲ. The results of the RDA suggested that[Deu(λPAR)/Dmix],Et, Ef* and TP were key regulatory factors for phytoplankton community composition in stage Ⅲ. The results indicated that TP was key regulatory factor for phytoplankton abundance in stage Ⅳ. The results of the RDA suggested that[Deu(λPAR)/Dmix] was key regulatory factor for phytoplankton community composition in stage Ⅳ.

[Purification Effect of Piggery Wastewater with Chlorella pyrenoidosa by Immobilized Biofilm-Attached Culture].

Piggery wastewater treatment with microalgae is a biological recycling technology. To evaluate the purification effect, this study investigated the treatment of piggery wastewater at different dilution ratios with Chlorella pyrenoidosa by attached cultivation and lipid production of algae cells and explored the tolerance of Chlorella pyrenoidosa to the piggery wastewater, which has high ammonia nitrogen. The piggery wastewater was diluted with purified water 1-, 2-, 5-, and 10-fold in culture media. The removal efficiencies of COD, ammonia nitrogen, total nitrogen, and total phosphorus and the enrichment effect of the heavy metals copper, zinc, and iron were measured. Meanwhile, we investigated the lipid production of Chlorella pyrenoidosa in variously diluted wastewater (1-, 2-, 5-, and 10-fold). It turned out that the purification effects of COD, ammonia nitrogen, total nitrogen, and total phosphorus were best when the piggery wastewater was diluted 5-fold, and the removal efficiencies were 86.8%, 94.1%, 85.2%, and 84.3%, respectively. Correspondingly, the lipid content was as high as 32.7%, and the removal efficiencies of the heavy metals copper, zinc, and iron were 72.9%, 70.0%, and 73.0%, respectively. The biomass productivity was 4.21 g·(m2·d)-1 at the end of the experiment. This research makes an effective connection between microalgae and piggery wastewater, which is difficult to purify deeply, and provides a theoretical basis for achieving algal biofuel production and decreasing the cost of wastewater treatment.

[Comparison of Relationship Between Conduction and Algal Bloom in Pengxi River and Modao River in Three Gorges Reservoir].

Pengxi River is the largest tributary in the northern bank of Yangtze River in the Three Gorges Reservoir (TGR) region, and serious algal bloom has been reported since 2003 when the TGR dam started impounding water. On the other hand, Modao River, a tributary in TGR locating in the same county with Pengxi River, was rarely reported with algal bloom in the same time period. In this study, water samples were collected on the same day in both rivers in spring and summer, the most likely blooming seasons in TGR, to compare the water quality parameters and Chlorophyll-a(Chl-a) concentration dynamics in order to understand the mechanism of algal bloom in TGR. The results showed that the maximum value of Chl-a in Pengxi river reached 60.5 µg·L-1 in spring, and was only 7.8 µg·L-1 in summer, while in Modao river the Chl-a content was 2.92 µg·L-1 in spring and 7.48 µg·L-1in summer. Both rivers stratified during samplings, but having layers of thermocline and hypolimnion with the lack of epilimnion, and most of Chl-a content was located in thermocline. Also in both rivers, TN and TP exceeded the international threshold for eutrophication, with the average TN and TP values of 2.305 mg·L-1 and 0.053 mg·L-1in Pengxi River in spring, and 1.673 mg·L-1 and 0.097 mg·L-1 in summer, respectively, while in Modao River the values were 1.875 mg·L-1 and 0.075 mg·L-1 in spring, and 1.79 mg·L-1 and 0.054 mg·L-1 in summer respectively. Nutrients concentrations showed no significant correlation with Chl-a. On the other hand, conductivity value and trend were totally different between the two rivers:in Modao River in spring, the conductivity in upstream was only 75% of that in the main stream of the Yangtze River, and the backwater from the main stream reached to the middle in Modao river, where the highest Chl-a among all the river sampling sites was detected; summer conductivity distribution was similar with that in spring. Different from Modao River, the conductivity in upstream of Pengxi River in spring was 150% of that in the main stream of Yangtze, the backwater from the main stream reached area between sampling sites of PX04 and PX05 (upper than the middle reach); its upstream had significantly high content of Chl-a and conductivity, and these two factors were significantly positively correlated. The study showed that other than N and P, other ions in the Pengxi River played an important role in bursting "bloom", and need to be considered regarding bloom control.

[Temporal and Spatial Distribution of Environmental Factors and Phytoplankton During Algal Bloom Season in Pengxi River, Three Gorges Reservoir].

Planktonic algae and Related Environmental Factors were monitored during the period of algal blooms season in 2014 (Spring April 17 and summer 27 July) in Pengxi river, Three Gorges Reservoir. Mathematical statistical tools were used to analyze the community structure of planktonic algae in Pengxi River with its environmental factors. The results of sampling in spring showed that except the estuary site, S1 and the site close by, S2, the waters stratified, but without epilimnion, only had metalimnion and hypolimnion; the upstream sites had larger temperature difference between water layers than did the downstream ones; from all the 8 sampling sites from estuary to upstream, water depth, and the temperature, pH, conductivity, dissolved oxygen, chlorophyll a, TN and TP of the surface layer (0-0.5 m deep) were significantly different (ANOVA, P < 0.05). 25 species (genus) of planktonic algae were identified. The abundance of species ranged from 2.76 x 104 cell · L⁻¹ to 145.8 x 104 cell · L⁻¹. Ceratium hirundinella was the main dominant species, and Anabaena sp. was the sub-dominant species. Algal bloom in upstream sampling sites S7 (63.4 x 104cell · L⁻¹) and S8 (145.8 x 104cell · L⁻¹)were relatively serious in spring. Temperature of water, pH , conductivity, dissolved oxygen and NO3⁻ were the key regulatory factors for phytoplankton abundance based on redundancy analysis ( RDA). The results of sampling in summer showed similar stratification trends among sites; the depth of the same 8 sampling sites, and their surface layer's temperature of water, turbidity, redox potential, pH, water depth, conductivity, chlorophyll a, NH4⁺, NO3⁻, total nitrogen and total phosphorus were significantly different (ANOVA, P < 0.05). 46 species (genus) of phytoplanktonic algae were identified. The abundance ranged from 9.56 x 104 cell · L⁻¹ to 278.88 x 104 cell · L⁻¹. Phormidium sp. was the main dominant species, and Anabaena sp. was the sub- dominant algae. Algal bloom at the lower part of the river, S2 (216.44 x 104 cell · L⁻¹), S3 (278.88 x 104 cell · L⁻¹) and S4 (108.12 x 104 cell · L⁻¹) were relatively serious in summer. Turbidity, depth of water, TN, oxidation-reduction potential, conductivity and dissolved oxygen were the key regulatory factors for phytoplankton abundance based on RDA. Stratification had important effect on algal bloom formation.

Nutrient spatial pattern of the upstream, mainstream and tributaries of the Three Gorges Reservoir in China.

A comprehensive monitoring program was conducted to investigate the nutrient spatial pattern in the mainstream of the Yangtze River from the Baihetan Dam down to the Three Gorges Dam located at the upper region of the Yangtze River in China. Samples were taken from 33 different sites from July 30 to August 19, 2011. The nutrient patterns of the three representative tributaries of the Three Gorges Reservoir (TGR)--the Modao, the Daning, and the Xiangxi Rivers--were also investigated. The results show that the mainstream of the TGR has a higher concentration of nitrogen and a lower concentration of phosphorus than that of the upper mainstream before the TGR. Moreover, it was found that nitrate-nitrogen (NO3-N) is the main nitrogen component, while particulate phosphorus predominates the total phosphorus (TP). It was found that the three representative tributaries of the TGR have lower total nitrogen (TN) concentrations compared to the corresponding sections of the mainstream TGR. Based on the nutrient spatial pattern, the nutrient flux was calculated. The total fluxes of TN, NO3-N, TP, and orthophosphate (PO4-P) from the upstream reach into the TGR are 2,155.06, 1,674.97, 212.98, and 83.42 t day(-1), respectively. The amount of nutrients imported from the TGR into its tributaries is more than the amount exported. It was determined that the Xiangxi River has the largest net rate of imported nitrogen at 7.66 t day(-1), whereas the Daning River has the largest net rate of imported phosphorus at 1.75 t day(-1). In addition, compared with the nutrients imported from the TGR into its tributaries, the nutrient flux from the upstream reach into the TGR contributes approximately less than 3 %.

Copper-catalyzed methyl esterification reactions via C-C bond cleavage.

The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.

[Characteristics of nutrient loss by runoff in sloping arable land of yellow-brown under different rainfall intensities].

In order to investigate the loss characteristics of N and P through surface flow and interflow under different rainfall intensities, a field experiment was conducted on the sloping arable land covered by typical yellow-brown soils inXiangxi River watershed by artificial rainfall. The results showed that the discharge of surface flow, total runoff and sediment increased with the increase of rain intensity, while the interflow was negatively correlated with rain intensity under the same total rainfall. TN, DN and DP were all flushed at the very beginning in surface flow underdifferent rainfall intensities; TP fluctuated and kept consistent in surface flow without obvious downtrend. While TN, DN and DP in interflow kept relatively stable in the whole runoff process, TP was high at the early stage, then rapidly decreased with time and kept steady finally. P was directly influenced by rainfall intensity, its concentration in the runoff increased with the increase of the rainfall intensity, the average concentration of N and P both exceeded the threshold of eutrophication of freshwater. The higher the amount of P loss was, the higher the rain intensity. The change of N loss was the opposite. The contribution rate of TN loss carried by surface flow increased from 36.5% to 57.6% with the increase of rainfall intensity, but surface flow was the primary form of P loss which contributed above 90.0%. Thus, it is crucial to control interflow in order to reduce N loss. In addition, measures should be taken to effectively manage soil erosion to mitigate P loss. The proportion of dissolved nitrogen in surface flow elevated with the decrease of rainfall intensity, but in interflow, dissolved form was predominant. P was exported mainly in the form of particulate under different rainfall intensities and runoff conditions.

[Estimation of releasing fluxes of sediment phosphorous in the Three Gorges Reservoir during late autumn and early winter].

In order to investigate the internal contamination load sources in the Three Gorges Reservoir (TGR), a field sampling campaign was carried out in November and December 2010. Phosphate contents (PO4(3-) -P) were determined in 6 mainstream and 9 estuary sediment cores of sediment-water interface in the TGR. The results showed that the PO4(3-) -P concentrations of pore water in sediments from tributaries and the corresponding overlying water were higher than those from the mainstream. The PO4(3-) -P contents in tributaries and mainstream ranged from 9.59-29.79 microg x L(-1) and 9.01-25.36 microg x L(-1), respectively. Based on calculations using the Fick's First Law, sediments located at GuoJiaba and Xiaojiang estuaries were the 'sink' of P, and the fluxes of sediment PO4(3-) -P were estimated to be -0.63 mg x (m2 x a)(-1) and -0.60 mg x (m2 x a)(-1), respectively. In other areas, PO4(3-) -P diffused from the pore water to the overlying water, and the diffusive fluxes were in the range of 0.15-2.47 mg x (m2 x a)(-1). With the assumption that molecular diffusion was the main process by which nutrients were transported from the pore water to the overlying water and the water body in the TGR was evenly mixed, the contribution of sediment phosphorus to the water body was only -0.011-0.098%. So far, with the Three Gorges Reservoir sediments as the internal contamination load sources, the phosphorous release didn't significantly influence the water quality. The sediments in the TGR may be a large P source in a period of future time after the external P source is controlled efficiently.

[Phosphorus output characteristics under different rainfall-runoffs in Gaolan River].

Through capturing the dynamics of water quantity and quality during varied intensities of rainfall, the variation characteristics of different forms of phosphorus and flux during the producing of runoff were studied systematically in Gaolan River watershed (a secondary tributary of Three Gorges Reservoir). Meanwhile, the phosphoric loadings from point and non-point sour,-were identified, respectively. The results show that: the variation of rainfall-runoff under " squat" rain was relatively slow, while un,c "pointed thin" rain it presented quickly both during rising and recession. Total phosphorus concentration increased quickly because soil carried particulate phosphorus into water under the heavy rainfall, while the relative variations of dissolved total phosphorus and orthophosphate concentration were slightly elevated. Compared with "squat" rain, the maximum value of total phosphorus concentration and flux were both higher in "pointed thin" rain, which led to the more heavily soil erosion. The dynamics of flux and concentratiorn of phosphorus were generally consistent with that of the flow rate between the two different types of rain. Phosphorus from non-point source accounts for 90% during the whole heavy rain. Because of the long lasted time during " squat" rain, the contribution of the "squat" rain outweighs the "pointed thin" rain.

[Effects of intrusions from Three Gorges Reservoir on nutrient supply to Xiangxi Bay].

Frequent spring blooms have been observed in tributary bays of Three Gorges Reservoir (TGR) since its initial filling. In order to study Three Gorges Reservoir of nutrients by the River tributaries reverse effect, a well-designed field monitoring plan was conducted. The results show: there are significant intrusions from Three Gorges Reservoir to Xiangxi Bay to the surface, middle and bottom with three forms of intrusion respectively. The unique flow characteristics provide a hydrodynamic background of nutrient distributions of Xiangxi Bay. The average instantaneous fluxes of the input TN and TP of the intrusions from the confluence were 501.92 g x s(-1) and 48.17 g x s(-1), respectively; TN and TP loads originated from intrusions accounted for 43.4% and 21.5%, respectively to total amount in the whole year. The study shows that intrusion of the total nitrogen input, a large proportion of total phosphorus, and reducing the pollution loads of tributaries and upper reach basin of Three Gorges Reservoir is the fundamental way to eradicate algal blooms.