Characteristics of Micro-Seismic Events Induced by Ground Collapse-A Case Study in the Rongxing Gypsum Mine in Hubei Province, China.

Mining activities can damage rock masses and easily induce ground collapse, which seriously threatens safe production in mining areas. Micro-seismic systems can monitor rock mass deformation signals in real time and provide more accurate data for rock mass deformation analysis. Therefore, in this study, the waveform characteristics of micro-seismic events induced by ground collapse in the Rongxing gypsum mine were analyzed; the occurrence of these events was introduced on the basis of Fast Fourier Transform, an established Frequency-Time-Amplitude model, in order to put forward the index of energy proportion of the main band. The results showed the following. (1) The seismic sequence type of ground collapse was foreshock-mainshock-aftershocks. The interval between the foreshock and mainshock was longer than that between the mainshock and aftershocks. (2) The deformation corresponding to the foreshock micro-seismic events was mainly that of a small-scale crack. The deformation corresponding to the micro-seismic events during the mainshock was characterized by the gradual development of small-scale cracks, and the development of large-scale cracks accelerated, accompanied by slight rock collapse. The deformation corresponding to the micro-seismic events during the aftershocks showed that almost no small-scale cracks developed, and the large-scale crack development was intense, and accompanied by numerous rock and soil mass collapses. (3) The observed decreasing frequency distribution and energy dispersion can be used as possible precursors of ground collapse.

PI3K/AKT1 Signaling Pathway Mediates Sinomenine-Induced Hepatocellular Carcinoma Cells Apoptosis: An in Vitro and in Vivo Study.

Hepatocellular carcinoma (HCC) is one of the most frequent cancers. Sinomenine (SIN) is a compound derived from Sinomenium acutum. Our previous investigations have found that SIN inhibited protein kinase B (AKT) signaling to induce autophagic death of tumor cells. However, whether inhibition of this pathway by SIN could impact the proliferation of HCC cells is unknown. Thus, we applied SIN to SK-Hep-1 cells and used cell counting kit 8 (CCK8), lactate dehydrogenase (LDH), colony formation and 5-ethynyl-20-deoxyuridine (EdU) incorporation experiments to detect cell viability. Then, staining with annexin V/propidium iodide (PI) coupled with terminal deoxynucleotidyl transferase-mediated biotinylated uridine 5'-triphosphate (UTP) nick end labeling (TUNEL) staining were utilized to monitor apoptosis. Changes in cell mitochondrial membrane capacity were explored via 5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining, whilst Western blot or immunohistochemistry was applied to evaluate the expression levels of key proteins, consisting of Cleaved Caspase 3, AKT1, B-cell leukemia/lymphoma 2 (BCL-2), phosphatidylinositol 3-kinase (PI3K) p85α, and Cleaved Caspase 9 etc. The Balb/c nude mice were utilized to establish HCC xenograft tumor model, administered by SIN. After treatments, the tumor volume along with weight were measured. The results illustrated that SIN suppressed SK-Hep-1 HCC cells' proliferation, enhanced the collapse of potential of the mitochondrial membrane, triggered cell apoptosis, down-regulated PI3K p85α, AKT1, BCL-2, Pro-Caspase 9, Pro-Caspase 3 expressions, and up-regulated Cleaved Caspase 9 and Cleaved Caspase 3 expressions in vitro and in vivo. Meanwhile, SIN reduced the tumor volume along with weight of mice. In addition, insulin-like growth factor-1 (IGF-1), a powerful activator of the PI3K/AKT pathway, could reverse the high apoptosis of SK-Hep-1 HCC cells induced by SIN. Overall, inhibition of PI3K/AKT1 signaling cascade by SIN induced HCC cells apoptosis.

Optimal ablation index parameters for radiofrequency ablation therapy of atrial fibrillation.

Objectives: To explore the optimal ablation index (AI) parameters for radiofrequency catheter ablation (RA) for treating atrial fibrillation (AF). Methods: Patients with AF (186) who underwent bilateral PVAI in the Department of Cardiology, Zhuhai People's Hospital, Guangdong Province, from March 2018 to October 2019 and received catheter ablation as first-round treatment, were grouped according to the received AI. Control group included patients (95) who received the recommended AI ablation (350-400 for posterior wall, 400-450 for non-posterior wall). Patients in optimal AI group were ablated with optimal AI (300-330 for posterior wall, 350-380 for non-posterior wall). Recurrence was defined as any AF, atrial tachycardia, or atrial flutter lasting more than 30 seconds without anti-arrhythmic drugs after the 3-month blank period. Results: Of 186 patients, 66 patients had paroxysmal atrial fibrillation and a mean CHA2DS2-VASc score of 2.83±1.64. Isolation rates of bilateral PVI in both groups were 91.4% and 93.6%, for patients with paroxysmal atrial fibrillation, and 81.7% and 80% for patients with persistent atrial fibrillation (P > 0.05). Left atrial function index (LAFI) decreased under the condition of sinus rhythm at the 3rd and 6th months (P < 0.05). LAFI improvement was significantly better in the optimal AI group than in the control group (P < 0.05). Rates of pain and cough during the ablation, and postoperative gastrointestinal discomfort and use of PPIs were higher in the control group (P < 0.05). The recurrence rate was 14.7% and 14.3% after 12 months of follow-up, respectively, and the difference was not statistically significant (P > 0.05). Conclusion: Radiofrequency ablation of AF, guided by optimal AI combined with impedance, can minimize atrial injury, prevent atrial failure, promote the recovery of atrial function, reduces intraoperative cough, pain, and postoperative gastrointestinal discomfort and use of PPIs.

Regiocontrolled Reductive Vinylation of Aliphatic 1,3-Dienes with Vinyl Triflates by Nickel Catalysis.

The regiocontrolled functionalization of 1,3-dienes has become a powerful tool for divergent synthesis, yet it remains a long-standing challenge for aliphatic substrates. Herein, we report a reductive approach for a branch-selective 1,2-hydrovinylation of aliphatic 1,3-dienes with R-X electrophiles, which represents a new selectivity pattern for diene functionalization. Simple butadiene, aromatic 1,3-dienes, and highly conjugated polyene were also tolerated. The combination of Ni(0) and the phosphine-nitrile ligand generally resulted in >20:1 regioselectivity with the retention of the geometry of the C3-C4 double bonds. This reaction proceeds with a broad substrate scope, and it allows for the conjugation of two biologically active units to form more complex polyene molecules, such as tetraene and pentaene as well as heptaene.

Cross-Electrophile C(sp2 )-Si Coupling of Vinyl Chlorosilanes.

The cross-electrophile coupling has become a powerful tool for C-C bond formation, but its potential for forging the C-Si bond remains unexplored. Here we report a cross-electrophile Csp2 -Si coupling reaction of vinyl/aryl electrophiles with vinyl chlorosilanes. This new protocol offers an approach for facile and precise synthesis of organosilanes with high molecular diversity and complexity from readily available materials. The reaction proceeds under mild and non-basic conditions, demonstrating a high step economy, broad substrate scope, wide functionality tolerance, and easy scalability. The synthetic utility of the method is shown by its efficient accessing of silicon bioisosteres, the design of new BCB-monomers, and studies on the Hiyama cross-coupling of vinylsilane products.

Highly Enantioselective Cross-Electrophile Aryl-Alkenylation of Unactivated Alkenes.

Enantioselective cross-electrophile reactions remain a challenging subject in metal catalysis, and with respect to data, studies have mainly focused on stereoconvergent reactions of racemic alkyl electrophiles. Here, we report an enantioselective cross-electrophile aryl-alkenylation reaction of unactivated alkenes. This method provides access to a number of biologically important chiral molecules such as dihydrobenzofurans, indolines, and indanes. The incorporated alkenyl group is suitable for further reactions that can lead to an increase in molecular diversity and complexity. The reaction proceeds under mild conditions at room temperature, and an easily accessible chiral pyrox ligand is used to afford products with high enantioselectivity. The synthetic utility of this method is demonstrated by enabling the modification of complex molecules such as peptides, indometacin, and steroids.

Clinical Efficacy of Low Molecular Heparin on Unexplained Recurrent Spontaneous Abortion.

BACKGROUND: To study the clinical effect of low molecular heparin on unexplained recurrent spontaneous abortion (URSA). METHODS: A total of 120 URSA patients were collected in our hospital from October 2015 to September 2017. They were divided into two groups: control group (n = 60) and observation group (n = 60). The patients in the control group were administered with progesterone and human chorionic gonadotropin, and the observation group with low molecular heparin. Pregnancy outcomes, incidence of complications in pregnancy and adverse drug reactions were compared in the two groups. RESULTS: The pregnancy success rate of patients in the observation group (90.00%) is higher than that in the control group (68.33%) (p < 0.05). The incidence of complications in pregnancy in the observation group (90.00%) is lower than those in the control group (68.33%) (p < 0.05). The incidence of adverse drug reactions between the patients in the observation group (20.00%) and those in the control group (23.33%) showed no significant difference (p > 0.05). CONCLUSIONS: Low molecular heparin treatment can improve pregnancy success rate and reduce the incidence of complications in the URSA patients. Low molecular heparin is characterized by safety and reliability and has potential for application in clinic.

RNA-Seq analysis reveals that multiple phytohormone biosynthesis and signal transduction pathways are reprogrammed in curled-cotyledons mutant of soybean [Glycine max (L.) Merr].

BACKGROUND: Soybean is one of the most economically important crops in the world. The cotyledon is the nutrient storage area in seeds, and it is critical for seed quality and yield. Cotyledon mutants are important for the genetic dissection of embryo patterning and seed development. However, the molecular mechanisms underlying soybean cotyledon development are largely unexplored. RESULTS: In this study, we characterised a soybean curled-cotyledon (cco) mutant. Compared with wild-type (WT), anatomical analysis revealed that the cco cotyledons at the torpedo stage became more slender and grew outward. The entire embryos of cco mutant resembled the "tail of swallow". In addition, cco seeds displayed reduced germination rate and gibberellic acid (GA3) level, whereas the abscisic acid (ABA) and auxin (IAA) levels were increased. RNA-seq identified 1,093 differentially expressed genes (DEGs) between WT and the cco mutant. The KEGG pathway analysis showed many DEGs were mapped to the hormone biosynthesis and signal transduction pathways. Consistent with assays of hormones in seeds, the results of RNA-seq indicated auxin and ABA biosynthesis and signal transduction in cco were more active than in WT, while an early step in GA biosynthesis was blocked, as well as conversion rate of inactive GAs to bioactive GAs in GA signaling. Furthermore, genes participated in other hormone biosynthesis and signalling pathways such as cytokinin (CK), ethylene (ET), brassinosteroid (BR), and jasmonate acid (JA) were also affected in the cco mutant. CONCLUSIONS: Our data suggest that multiple phytohormone biosynthesis and signal transduction pathways are reprogrammed in cco, and changes in these pathways may partially contribute to the cco mutant phenotype, suggesting the involvement of multiple hormones in the coordination of soybean cotyledon development.

A soybean MADS-box protein modulates floral organ numbers, petal identity and sterility.

BACKGROUND: The MADS-box transcription factors play fundamental roles in reproductive developmental control. Although the roles of many plant MADS-box proteins have been extensively studied, there are almost no functional studies of them in soybean, an important protein and oil crop in the world. In addition, the MADS-box protein orthologs may have species-specific functions. Controlling male fertility is an important goal in plant hybrid breeding but is difficult in some crops like soybean. The morphological structure of soybean flowers prevents the cross-pollination. Understanding the molecular mechanisms for floral development will aid in engineering new sterile materials that could be applied in hybrid breeding programs in soybean. RESULT: Through microarray analysis, a flower-enriched gene in soybean was selected and designated as GmMADS28. GmMADS28 belongs to AGL9/SEP subfamily of MADS-box proteins, localized in nucleus and showed specific expression patterns in floral meristems as well as stamen and petal primordia. Expression of GmMADS28 in the stamens and petals of a soybean mutant NJS-10Hfs whose stamens are converted into petals was higher than in those of wild-type plants. Constitutive expression of GmMADS28 in tobacco promoted early flowering and converted stamens and sepals to petals. Interestingly, transgenic plants increased the numbers of sepal, petal and stamen from five to six and exhibited male sterility due to the shortened and curly filaments and the failure of pollen release from the anthers. The ectopic expression of GmMADS28 was found to be sufficient to activate expression of tobacco homologs of SOC1, LEAFY, AGL8/FUL, and DEF. In addition, we observed the interactions of GmMADS28 with soybean homologs of SOC1, AP1, and AGL8/FUL proteins. CONCLUSION: In this study, we observed the roles of GmMADS28 in the regulation of floral organ number and petal identity. Compared to other plant AGL9/SEP proteins, GmMADS28 specifically regulates floral organ number, filament length and pollen release. The sterility caused by the ectopic expression of GmMADS28 offers a promising way to genetically produce new sterile material that could potentially be applied in the hybrid breeding of crops like soybean.

GmNAC5, a NAC transcription factor, is a transient response regulator induced by abiotic stress in soybean.

GmNAC5 is a member of NAM subfamily belonging to NAC transcription factors in soybean (Glycine max (L.) Merr.). Studies on NAC transcription factors have shown that this family functioned in the regulation of shoot apical meristem (SAM), hormone signalling, and stress responses. In this study, we examined the expression levels of GmNAC5. GmNAC5 was highly expressed in the roots and immature seeds, especially strongly in immature seeds of 40 days after flowering. In addition, we found that GmNAC5 was induced by mechanical wounding, high salinity, and cold treatments but was not induced by abscisic acid (ABA). The subcellular localization assay suggested that GmNAC5 was targeted at nucleus. Together, it was suggested that GmNAC5 might be involved in seed development and abiotic stress responses in soybean.

Based on bound water characteristics study of microporosity characteristics and mechanical properties evolution of copper-contaminated laterite.

The potential impact of heavy metal ion infiltration on macroscopic and microscopic soil properties is a subject of academic interest. Laterite has an extensive distribution in southern China and is extensively utilized as a vertical containment wall for landfills. Consequently, there is a need to investigate how heavy metal ions affect laterite's microstructure and mechanical properties. To examine the impact of Cu2+ on laterite's microporous characteristics and mechanical properties, laboratory tests were conducted on the permeability, shear strength, microporous characteristics, and strong absorbed water content of Cu2+-contaminated laterite. The results show that Cu2+ hydrolysis generates an acidic environment, which leads to erosion of the cementing substance between the laterite particles, increasing the laterite's porosity and decreasing the soil's cohesive strength, thus affecting the shear strength and permeability of the laterite. When the concentration of Cu2+ is 5.0 g/L, the laterite demonstrated the most significant decrease in shear strength, 43.01%, while the permeability coefficient increased from 3.24 × 10-8 cm/s to 1.32 × 10-7 cm/s. Meanwhile, Cu2+ changes the content of strong absorbed water in laterite. The change of strong absorbed water content will affect the Van der Waals between laterite particles, promote the evolution of soil micropore structure, and lead to a decrease in the proportion of intra-aggregate pores (d < 1 µm) and an increase in the proportion of inter-aggregate pores (1 µm < d < 10 µm), which in turn affects the macroscopic shear strength and permeability. This study has improved our understanding of the mechanisms underlying the microporosity and mechanical property evolution of laterite when subjected to heavy metal attack.

Curative effect of wrist-ankle acupuncture on postpartum abdominal pain and its influence on serum ß-EP level in puerpera. / è •è¸é’ˆæ²»ç–—äº§åŽè ¹ç—›çš„ä¸´åºŠç–—æ•ˆåŠå¯¹äº§å¦‡è¡€æ¸ ß-EP水平的影响.

OBJECTIVES: To observe the clinical effect of wrist-ankle acupuncture on postpartum abdominal pain and its influence on serum beta-endorphin (ß-EP) level in puerpera. METHODS: Seventy patients with postpartum abdominal pain were randomly divided into an acupuncture + herbal medication group (35 cases, 1 case dropped out) and a herbal medication group (35 cases, 2 cases dropped out). In the herbal medication group, 1 day after delivery, modified shenghua decoction was taken orally, one dose a day. In the acupuncture + herbal medication group, on the basis of herbal medication, wrist-ankle acupuncture was given at the Lower 1 and Lower 2 of the ankles, once daily. The duration of treatment was 3 days in the two groups. Before and after treatment, the score of visual analogue scale (VAS) for pain, serum ß-EP level, uterine fundus height, postpartum conditions of lochia and the uterine recovery at 42 days postpartum were compared in the patients of the two groups. RESULTS: At each time point after treatment (24 h, 48 h and 72 h after delivery), VAS scores and the uterine fundus height were reduced as compared with those before treatment (2 h after delivery) in the two groups (P<0.05); these indexes in the acupuncture + herbal medication group were lower than those in the herbal medication group (P<0.05). After treatment (72 h after delivery), ß-EP levels in the serum were increased when compared with those before treatment in the two groups (P<0.05), and the ß-EP level in the acupuncture + herbal medication group was higher than that in the herbal medication group (P<0.05). The volume of postpartum lochia discharge in the acupuncture + herbal medication group was higher than that in the herbal medication group (P<0.05), while the duration of postpartum lochia discharge and the total time of lochia discharge were shorter (P<0.05). Regarding the recovery of the uterus at 42 days postpartum, there was no statistical significance between the two groups (P>0.05). CONCLUSIONS: Wrist-ankle acupuncture obviously reduces the degree of postpartum abdominal pain and promotes the lochia discharge and the uterine recovery. The effect mechanism may be related to the up-regulation of serum ß-EP level and the increase of pain threshold so that analgesia is obtained.

Palladium-Catalyzed Silylation of 2,3-Allenols with Unactivated Disilanes: Access to 2-Silyl-1,3-butadienes and α-Silyl-ß-hydroxy Vinylsilanes.

Regioselective silylation of 2,3-allenols with disilanes was carried out under catalysis of Pd2dba3/P(o-MeOC6H4)3. In the presence of Cs2CO3, the reaction achieved 2-silyl-1,3-dienes. Reaction of 1-aryl-2,3-allenols gave the products with excellent Z/E selectivity and E-isomers as the major species. Reaction of α-alkylallenols or α-alkyl-α-aryl-allenols resulted in products with moderate Z/E selectivity and E-isomers are also major. Without a base, the reaction produced α-silyl-ß-hydroxyl vinylsilanes, which were converted to 2-silyl-1,3-dienes upon treatment with Cs2CO3.

Copper-Catalyzed Reaction of 2,3-Allenols with Silylzinc Reagents: Access to 2-Silyl-1,3-butadienes.

Reaction of 2,3-allenols with PhMe2SiZnCl or Ph2MeSiZnCl under catalysis of IPrCuCl or SIPrCuCl was carried out, affording 2-silyl-1,3-butadienes. Secondary and tertiary 2,3-allenols could be used as coupling partners. Reaction of secondary 2,3-allenols gave (E)-2-silyl-1,3-butadienes as the only products.

Efficiency of Pb, Zn, Cd, and Mn Removal from Karst Water by Eichhornia crassipes.

This study experimentally investigated heavy metal removal and accumulation in the aquatic plant Eichhornia crassipes. Pb, Zn, Cd, and Mn concentrations, plant morphology, and plant functional groups were analyzed. Eichhornia crassipes achieved high removal efficiency of Pb and Mn from karst water (over 79.5%), with high proportion of Pb, Zn, and Cd absorption occurring in the first eight days. The highest removal efficiencies were obtained at initial Pb, Zn, Cd, and Mn concentrations of 1 mg/L, 2 mg/L, 0.02 mg/L, and 0.2 mg/L, respectively. Eichhornia crassipes exhibited a high bioconcentration factor (Mn = 199,567 > Pb = 19,605 > Cd = 3403 > Zn = 1913) and a low translocation factor (<1). The roots accumulated more Pb, Zn, Cd, and Mn than the stolons and leaves due to the stronger tolerance of roots. The voids, stomas, air chambers, and airways promoted this accumulation. Pb, Cd, Zn, and Mn likely exchanged with Mg, Na, and K through the cation exchange. C≡C, C=O, SO42-, O-H, C-H, and C-O played different roles during uptake, which led to different removal and accumulation effects.

Hyperoside attenuates pregnancy loss through activating autophagy and suppressing inflammation in a rat model.

AIMS: Recurrent pregnancy loss (RPL) is one of the most common obstetrical diseases, which is a manifestation of antiphospholipid syndrome (APS) with no effective therapy methods. Autophagy and inflammatory responses both play an important role in the pathogenesis of RPL and hyperoside has been demonstrated to have multifarious bioactivities including enhancing autophagy and anti-inflammation. This study aims to investigate the effect of hyperoside on anticardiolipin (aCL)-IgG fractions-induced pregnancy loss. MAIN METHODS: In the present study, the effect of hyperoside was evaluated in a rat model of pregnancy loss induced by aCL-IgG fractions isolated from serum of APS patients. The fetuses were counted and the placentas were weighted and the protein expressions of inflammation and autophagy were measured by western blot analysis. KEY FINDINGS: Treatment with hyperoside (40 mg/kg) improved pregnancy outcome manifest as increasing the weight of fetuses and decreasing the fetal resorption rate. In addition, hyperoside treatment downregulated the expressions of phosphorylated mammalian target of rapamycin (mTOR), phosphorylated p70S6 Kinase (S6K) and inhibited the expressions of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and NF-kB p-p65 in pregnancy loss animal models. SIGNIFICANCE: Hyperoside attenuated pregnancy loss through regulating mTOR/S6K and TLR4/MyD88/NF-kB signaling pathways, which may provide a potential drug candidate for recurrent pregnancy loss therapy.

Hyperoside Protects Human Umbilical Vein Endothelial Cells Against Anticardiolipin Antibody-Induced Injury by Activating Autophagy.

Anticardiolipin antibody (aCL), an important characterization of antiphospholipid syndrome, shows an intense association with vascular endothelial injury. Hyperoside is a flavonoid extracted from medicinal plants traditionally used in Chinese medicines, displaying anti-inflammatory, anti-cancer, and anti-oxidative properties in various diseases. Recent studies have shifted the focus on the protective effects of hyperoside on vascular endothelial injury. However, little is known about the mechanisms involved. In the present study, we investigated the effect of hyperoside on aCL-induced injury of human umbilical vein endothelial cells (HUVECs) in vitro. Our data illustrated that aCL induced HUVEC injury via inhibiting autophagy. Hyperoside reduced aCL-induced secretion of proinflammatory cytokines IL-1ß and IL-8 and endothelial adhesion cytokines TF, ICAM1, and VCAM1 in HUVECs. Additionally, hyperoside activated autophagy and suppressed the mTOR/S6K and TLR4/Myd88/NF-κB signaling transduction pathways in aCL-induced HUVECs. To the best of our knowledge, this is the first study to investigate the effect of hyperoside on aCL-induced injury, as well as offer insights into the involved mechanisms, which is of great significance for the treatment of antiphospholipid syndrome.

Effects and Mechanisms of Calcium Ion Addition on Lead Removal from Water by Eichhornia crassipes.

Karst water is rich in calcium ions (Ca2+) and exhibits poor metal availability and low biodegradation efficiency. This study sought to analyze the effects and mechanisms of Ca2+ on lead (Pb) removal and absorption by Eichhornia crassipes (a floating plant common in karst areas). Moreover, the morphology and functional groups of E. crassipes in water were characterized via SEM, and FTIR. The results demonstrated that the removal rate of Pb in karst water (85.31%) was higher than that in non-karst water (77.04%); however, the Pb bioconcentration amount (BCA) in E. crassipes roots in karst water (1763 mg/kg) was lower than that in non-karst water (2143 mg/kg). With increased Ca2+ concentrations (60, 80, and 100 mg/L) in karst water, the Pb removal rate increased (85.31%, 88.87%, and 92.44%), the Pb BCA decreased (1763, 1317, and 1095 mg/kg), and the Ca BCA increased (6801, 6955, and 9368 mg/kg), which was attributed to PbCO3 and PbSO4 precipitation and competitive Ca and Pb absorption. High Ca2+ concentrations increased the strength of cation exchange, alleviated the fracture degree of fibrous roots, reduced the atrophy of vascular bundles, protected the cell wall, promoted C-O combined with Pb, enhanced the strength of O‒H, SO42-, C=O, and reduced the oxidization of alkynyl acetylene bonds.

[Major Ionic Characteristics and Controlling Factors of Karst Groundwater at Xiangshui, Chongzuo].

To investigate the major ionic characteristics, seasonal variation, and controlling factors of karst groundwater at Xiangshui, Chongzuo, 210 groundwater samples were collected and measured in wet season, dry season, and flat season in 2016. The controlling factors of karst groundwater were analyzed by using multivariate statistical analysis method. The results showed that the groundwater samples were weakly alkaline fresh water and rich in Ca2+ and HCO3-, which accounted for more than 75% and 70% of total ion concentration. The average concentrations of K+, Na+, Cl-, and NO3- decreased in the order of wet season > flat season > dry season. None of the concentrations of Ca2+, Mg2+, HCO3-, SO42-, pH, TDS, TZ+, and TZ- showed significant seasonal variation. The hydrochemical characteristics were found to be of HCO3-Ca type and mainly determined by carbonate rock dissolution. Only a small proportion of them were of HCO3·Cl-Ca and HCO3·SO4-Ca type in wet season and flat season, Cl·NO3-Ca type appeared in flat season, and HCO3-Ca·Mg type appeared in dry season, reflecting the influence of dolomite and ferric mudstone dissolution in the stratum, and of NO3- and Cl- input from anthropogenic activities. Groundwater Ca2+ and HCO3- mainly came from limestone dissolution; Na+, Cl-, K+, and NO3- came from atmospheric precipitation and human activities; while Mg2+ and SO42- came from dolomite and ferric mudstone dissolution. The chemical composition of groundwater was controlled by water-rock interaction, the groundwater in the carbonate aquifer was controlled by carbonate rocks dissolution, and the groundwater in villages and densely populated areas was affected by atmospheric precipitation and human activity.

[Water Quality Analysis and Health Risk Assessment for Groundwater at Xiangshui, Chongzuo].

To investigate the environmental quality and human health risks of different types of groundwater at Xiangshui, Chongzuo, several regular water quality indexes and concentrations of metals in 60 groundwater samples were measured and analyzed. The environmental quality of groundwater was analyzed by means of the Nemerow index. The health risks were assessed by using a human health risk assessment model. The regular water quality indexes and concentrations of metals of the well water, spring water, and underground river water exceeded the standards to different degrees. The environmental quality of groundwater was at a poor grade. The comprehensive evaluation score of underground river water (F=4.26) was the lowest. The well water had the same score as spring water (F=7.10). The high hardness and salinity were conducive to enrichment of Cr, and the reducing environment was of great advantage for the enrichment of As. The environmental geochemistry of Zn, Pb, Cd, and Cu was similar. The sources of Fe, Al, and Mn were similar. The results of the health risk assessment indicated that the health risks of well water, spring water, and underground river water were relatively high. The health risks decreased in the order of well water > underground river water > spring water. The health risks mainly came from the carcinogenic metallic element Cr. Carcinogenic risks were 4-6 orders of magnitude higher than non-carcinogenic risks. Carcinogenic risks were higher than the maximum allowance levels (5.0×10-5 a-1). Non-carcinogenic risks were lower than the allowance levels (10-6 a-1). Children had greater health risks than adults. The health risks of metals through the drinking pathway were 2-3 orders of magnitude higher than the values caused by the dermal contact pathway. For the sake of drinking water safety, the well water, underground river water, and spring water should be properly treated and the concentration of Cr in groundwater should be controlled before drinking.