Anthropogenic activities drive the distribution and ecological risk of antibiotics in a highly urbanized river basin.

Although antibiotics are widely detected in river water, their quantitative relationships with influencing factors in rivers remain largely unexplored. Here, 15 widely used antibiotics were comprehensively analyzed in the Dongjiang River of the Pearl River system. The total antibiotic concentration in river water ranged from 13.84 to 475.04 ng/L, with fluoroquinolones increasing from 11 % in the upstream to 38 % in the downstream. The total antibiotic concentration was high downstream and significantly correlated with the spatial distribution of population density, animal production, and land-use type. The total risk quotient of antibiotics for algae was higher than that for crustaceans and fish. Based on the optimized risk quotient method, amoxicillin, ofloxacin, and norfloxacin were identified as priority antibiotics. The key predictors of antibiotic levels were screened through Mantel test, correlation analysis, and multiple regression models. Water physicochemical parameters significantly impacted antibiotics and could be used as easy-to-measure surrogates associated with elevated antibiotics. Cropland negatively affected fluoroquinolones and sulfonamides, whereas urban land exerted positive impacts on fluoroquinolones, ß-lactam, and sulfonamides. In the main stream, population, animal production, urbanization status, and economic development had key effects on the distribution of florfenicol, norfloxacin, ofloxacin, and sulfadiazine.

[Fraction Characteristic and Risk Assessment of Heavy Metals in Surface Sediments of the Yellow River Mainstream].

Heavy metals(HMs) are highly toxic and do not easily degrade in the environment. They can accumulate in the human body through the food chain, with serious impacts on the ecological environment and human health. In this study, 14 sampling sites along the mainstream of the Yellow River were investigated, and the total content and chemical fractions of six heavy metals(As, Cd, Cr, Cu, Pb, and Zn) in sediments were analyzed. The geo-accumulation index, potential ecological risk index, and risk assessment coding were used to assess the contamination level and bioavailability of HMs in sediment. Principal component analysis and redundancy analysis were used to identify the main sources of HMs. The results showed that the average content of heavy metals was in the order of Cr>Zn>Cu>Pb>As>Cd. Cd had the highest excess rate relative to the background value of each reach, reaching 85.7%. In the sediments, As, Zn, Pb, and Cu were predominantly in the oxidizable fraction(F3:sulfide and organic matter-bound), Cd was mainly occupied by the acid-soluble(F1:exchangeable and carbonate-bound) and a residual fraction(F4:mineral matrix-bound), and Cr was predominantly in the residual fraction. As, Cr, Cu, Pb, and Zn showed the lowest bioavailability in the upstream, increased in the midstream, and finally decreased in the downstream. The risk assessment showed that Cd, the element with the highest pollution risk level in the Yellow River, was prone to pose a serious threat to the ecological environment and should be prevented and controlled first. The PCA and RDA analyses revealed that fine sediment and total organic matter controlled HMs contamination. Therefore, the prevention and control of soil erosion and sediment migration should be emphasized to control HMs pollution in the Yellow River Basin.

Monte Carlo simulation and delayed geochemical hazard revealed the contamination and risk of arsenic in natural water sources.

Due to its ubiquity and carcinogenicity, the geochemical behavior and health risks of arsenic (As) have been a research focus worldwide. A comprehensive investigation was conducted on the contamination and ecological and health risks of As in the Zijiang River (ZR)-a natural water source. The concentration ranges of As were separately 1.36-6.23 µg/L, 11.42-74.53 mg/kg, and 1.26-130.68 µg/L in surface waters (dissolved), sediments, and pore waters. The concentrations of As in the midstream pore waters and sediments were relatively high, which was related to mining, dam interception, and sediment resuspension. The Monte Carlo simulation results showed that the occurrence probability of As contamination and static risk in sediments was low, however, in the midstream, the secondary risk caused by the release of As should be given more consideration. In the sediments, the transformation paths and the dynamic risk of As were explored based on the delayed geochemical hazard model, showing that there was a probability of a potential burst of 26.47% - 55.88% in the sediments of the ZR. Although at the detected surface waters, the total risk of the noncarcinogenicity and carcinogenicity of As were low, overall adults have lower health risks than children, and As exposure in children should be of concern. This study complements the further understanding of the geochemical behavior of arsenic, which can be extended to other toxic metal(loid)s.

Mechanochemical remediation of lindane-contaminated soils assisted by CaO: Performance, mechanism and overall assessment.

Soil contamination caused by persistent organic pollutants (POPs) has been a worldwide concern for decades. With lindane-contaminated soil as the target, a mechanochemical method assisted by CaO was comprehensively evaluated in terms of its remediation performance, degradation mechanism and overall assessment. The mechanochemical degradation performance of lindane in cinnamon soil or kaolin was determined under different additives, lindane concentrations and milling conditions. 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazinyl free radical (DPPH•) and electron spin resonance (ESR) tests evidenced that the degradation of lindane in soil was caused mainly by the mechanical activation of CaO to produce free electrons (e-) and the alkalinity of the generated Ca(OH)2. Dehydrochlorination or dechlorination by elimination, alkaline hydrolysis, hydrogenolysis and the subsequent carbonization were the main degradation pathways of lindane in soil. The main final products included monochlorobenzene, carbon substances and methane. The mechanochemical method with CaO was proved to also efficiently degrade lindane in three other soils and other hexachlorocyclohexane isomers and POPs in soil. The soil properties and soil toxicity after remediation were assessed. This work presents a relatively clear discussion of various aspects of the mechanochemical remediation of lindane-contaminated soil assisted by CaO.

Riverine antibiotic occurrence and potential ecological risks in a low-urbanized and rural basin of the middle Yangtze River: Socioeconomic, land use, and seasonal effects.

This study firstly investigated the effects of season, land use, and socioeconomic on the spatiotemporal changes of riverine antibiotic concentrations in a low urbanized and rural watershed. In the dry and wet seasons, water samples were collected and analyzed for 15 antibiotics. The results indicated that 14 antibiotics, excluding leucomycin, were detected. Monsoon led to significantly lower total antibiotic concentrations in the wet season (22.0ngL-1) than in the dry season (51.2ngL-1). Total antibiotic concentrations were dominated by amoxicillin (below limit of detection (

Mercury contamination in the water and sediments of a typical inland river - Lake basin in China: Occurrence, sources, migration and risk assessment.

In the area affected by non-ferrous metal mining activities, mercury (Hg) contamination in the water and sediments posed potential risks to ecology and human health. In this study, river water and sediment samples were collected in the Zijiang river - South Dongting Lake basin to analyze Hg residues, identify potential Hg sources and evaluate the ecological and health risks posed by Hg contamination. In this study, the average concentrations of THg, PHg, DHg and DMeHg in river water were 38.05 ± 27.13 ng/L, 25.18 ± 26.83 ng/L, 12.88 ± 9.64 ng/L and 0.29 ± 0.07 ng/L, respectively. The THg and MeHg contents in sediments were 234.24 ± 152.93 µg/kg and 0.48 ± 0.16 µg/kg, respectively. The more enrichment of Hg in sediments was observed in the Zijiang River than in the South Dongting Lake, especially in the upstream and midstream regions. Two potential Hg sources in the basin were identified by correlation matrix, principal component analysis (PCA) and positive matrix factorization (PMF) model. The comparable Hg flux with other rivers worldwide was found in the Zijiang River (0.53 Mg/y). Furthermore, it was found by the delayed geochemical hazard (DGH) model that the ecological risk of Hg was more significant in the Zijiang River with more frequent transformation pathways. For different populations, the health risk values caused by Hg were all lower than the USEPA's guideline value. This study provided sound evidence for further control of Hg contamination.

Activation of persulfate by vanadium oxide modified carbon nanotube for 17ß-estradiol degradation in soil: Mechanism, application and ecotoxicity assessment.

Steroid hormones in the environment have attracted public attention because of their high endocrine-disrupting activity even at rather low exposure level. Excessive hormones in the soil from the pollutant discharge of intensive farming would pose a potential threat to the ecology and the human health. Vanadium oxide modified carbon nanotube (VOX-CNT) was synthesized and applied as persulfate (PDS) activator to reduce17ß-estrogen (17ß-E2) in soil. 86.06 % 17ß-E2 could be degraded within 12 h. Process of materials exchange during oxidation was interfered by soil, resulting in insufficient degradation of 17ß-E2, but the active species involved in 17ß-E2 degradation would also be enriched by it. 17ß-E2 was adsorbed on the VOX-CNT surface and directly degraded mainly by the active species generated on the catalyst surface, and •OH dominated the degradation of 17ß-E2 in VOX-CNT/PDS system. CO, defective sites and vanadium oxides on the surface of VOX-CNT contributed to the generation of activate species. Oxidizer dosage, catalyst dosage, water-soil ratio and soil properties would affect the degradation of 17ß-E2. The ecotoxicological impact on soil caused by VOX-CNT/PDS was acceptable, and would be weakened with time. Additionally, a rapid decrease in the concentration of 17ß-E2 and the promotion of maize growth were observed with VOX-CNT/PDS in situ pilot-scale remediation. Those results reveal that VOX-CNT/PDS is a potential technology to remove excessive steroid hormone from soil around large-scale livestock and poultry farms.

Distribution, partitioning, and health risk assessment of organophosphate esters in a major tributary of middle Yangtze River using Monte Carlo simulation.

Globally, organophosphate esters (OPEs) have attracted substantial attention because of their ubiquity in the environment, toxicity, and potential ecological and health risks. This study comprehensively investigated the occurrence, partitioning, and spatial distribution of nine ordinary monomeric OPEs (m-OPEs) and three emerging oligomeric OPEs (o-OPEs) in a major tributary of the middle Yangtze River, which is the Zijiang River (ZR), and their associated potential health risks. Total OPE concentrations ranged from 18.8 to 439 ng L-1, 1.40 to 19.1 ng L-1, and 3.71 to 77.3 ng g-1 dw in the surface water, suspended particulate matter (SPM), and sediment, respectively. Tris (2-chloroisopropyl) phosphate (TCPP) dominated the water (61.3%) and sediment (60.1%) samples, whereas tris (2-butoxyethyl) phosphate (TBOEP) was present in the SPM (59.0%) samples. The proportion of o-OPEs was low in all three media, ranging from 0.60% to 1.90%. Field-based log Koc values of the frequently detected OPEs were higher than those predicted by EPI Suite and were negatively correlated with temperature. The spatial distribution of OPEs in the water and hierarchical cluster analysis suggested that sewage treatment plant effluents and the mining industry were the main sources of OPEs in the ZR. The total noncarcinogenic and carcinogenic risks of OPEs in the water were low at the detected concentrations, even in the high-exposure scenario.

Historical records of trace metals in two sediment cores of Jiaozhou Bay, north China.

To investigate the long-term effects of urbanization and industrialization on coastal trace metal contamination, two sediment cores, Q21 (representing 1965-2018) and Q23 (representing 1986-2018), collected from the adjacent coasts of the east old town and west new area of Qingdao were analyzed. Although the concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, Sc, and Zn were higher in Core Q21, the increasing trends in their concentrations and contamination levels were more obvious in Q23, especially since the 2000s. Moreover, the urbanization rates of the new area (1978-2017) were significantly positively correlated with the historical metal concentrations in Q23. Affected by the rapid socio-economic development in the new area, the combined excessive concentrations of the eight metals (excluding Sc) increased faster in Q23 (0.14-78.4 mg/kg) than Q21 (0.58-45.3 mg/kg). Overall, the sediment Core Q23 experienced higher trace metal contamination and ecological risks than Core Q21.

Quantitative source identification and environmental assessment of trace elements in the water and sediment of rivers flowing into Laizhou Bay, Bohai Sea.

The concentrations, sources, and ecological risks of nine trace elements in nine rivers flowing into Laizhou Bay were investigated. The dissolved element concentrations were 1.85-74.4, 0.01-0.47, 0.15-3.46, 1.54-19.7, 2.92-45.1, 1.72-11.5, 1.02-8.35, 0.10-1.02, and 21.4-185 µg/L for As, Cd, Co, Cr, Cu, Ni, Sc, Pb, and Zn, respectively. Zinc was the most abundant element in the sediments, with an average concentration of 106 mg/kg, followed by Cr (64.5 mg/kg), Cu (25.5 mg/kg), Pb (24.3 mg/kg), Ni (23.4 mg/kg), Co (10.9 mg/kg), Sc (8.14 mg/kg), As (6.75 mg/kg), and Cd (0.16 mg/kg). Elements including Co, Cr, Ni, and Sc were mainly from natural sources and As, Cd, Cu, Pb, and Zn were largely influenced by anthropogenic activities such as agricultural practice, industrial production, river transportation, and urbanization. Overall, the rivers flowing into Laizhou Bay experienced slight pollution and ecological risk. However, the severe element contamination in Jie River deserves continuous attention.

Insights into the spatiotemporal occurrence and mixture risk assessment of household and personal care products in the waters from rivers to Laizhou Bay, southern Bohai Sea.

Household and personal care products (HPCPs) are a kind of contaminants closely related to daily life, capturing worldwide concern. To our knowledge, this is the first attempt focusing on the spatiotemporal occurrence and mixture risk of HPCPs in the waters from rivers to Laizhou Bay. Nine HPCPs were quantitated in 216 water samples gathered from Laizhou Bay and its adjacent rivers in 2018, 2019, and 2021 to reveal the spatiotemporal occurrence and mixture ecological risks in Laizhou Bay. Eight HPCPs were detected with detection frequencies ranging from 74% to 100%. The total concentrations were in the ranges 105-721 ng L-1 in river water and 51.3-332 ng L-1 in seawater. The HPCPs were dominated by p-hydroxybenzoic and triclosan, which together contributed over 75% of the total HPCPs. The average level of the total HPCP concentration in the summer of 2018 (96.1 ng L-1) was slightly exceed that in the spring of 2019 (91.6 ng L-1), which is associated with the higher usage of HPCPs and enhanced tourism during summer. However, the highest total concentrations were found in spring of 2021 (124 ng L-1 in average), which was attribute to a higher level of methylparaben, a predominant paraben used as preservatives in commercial pharmaceuticals of China. Influenced by riverine inputs and ocean currents, higher HPCP concentrations in Laizhou Bay were found nearby the estuary of Yellow River and the southern part of the bay. Triclosan should be given constant concern considering its medium to high risks (RQ > 0.1) in nearly 80% of the water samples. The cumulative risk assessment in two approaches revealed that HPCP mixtures generally elicit medium or high risk to three main aquatic taxa. Considering the worldwide outbreak of COVID-19, the levels and risks of multiple HPCPs in natural waters requires constant attention in future studies.

Sources, trophodynamics, contamination and risk assessment of toxic metals in a coastal ecosystem by using a receptor model and Monte Carlo simulation.

Heavy metal (HM) pollution in coastal ecosystems have posed threats to organisms and human worldwide. This study comprehensively investigated the concentrations, sources, trophodynamics, contamination, and risks of six HMs in the coastal ecosystem of Jiaozhou Bay, northern China, by stable isotope analysis, positive matrix factorization (PMF), and Monte Carlo simulation. Overall, Co, Cu, Ni, Pb, and Zn were significantly bio-diluted in the food web, while Cr was significantly biomagnified with a trophic magnification factor of 1.23. In addition, trophodynamics of the six HMs was different among fish, mollusk, and crustacean. Furthermore, detailed transfer pathways of six HMs in the food web including eight trophic levels were different from one another. Bioaccumulation order of the six HMs was Cu > Zn > Co, Cr, Ni, and Pb. Zinc concentrations were the highest in seawater, sediments, and organisms. Anthropogenic sources contributed to 71% for Zn, 31% for Cu and Pb, and 27% for Co, Cr, and Ni in the sediment, which was moderately contaminated with moderate ecological risk. However, the human health risk of HMs from eating seafood was relatively low. To protect the Jiaozhou Bay ecosystem, HM contamination should be further controlled in future.

Retrospective Study on the Influencing Factors and Prediction of Hospitalization Expenses for Chronic Renal Failure in China Based on Random Forest and LASSO Regression.

Aim: With the improvement in people's living standards, the incidence of chronic renal failure (CRF) is increasing annually. The increase in the number of patients with CRF has significantly increased pressure on China's medical budget. Predicting hospitalization expenses for CRF can provide guidance for effective allocation and control of medical costs. The purpose of this study was to use the random forest (RF) method and least absolute shrinkage and selection operator (LASSO) regression to predict personal hospitalization expenses of hospitalized patients with CRF and to evaluate related influencing factors. Methods: The data set was collected from the first page of data of the medical records of three tertiary first-class hospitals for the whole year of 2016. Factors influencing hospitalization expenses for CRF were analyzed. Random forest and least absolute shrinkage and selection operator regression models were used to establish a prediction model for the hospitalization expenses of patients with CRF, and comparisons and evaluations were carried out. Results: For CRF inpatients, statistically significant differences in hospitalization expenses were found for major procedures, medical payment method, hospitalization frequency, length of stay, number of other diagnoses, and number of procedures. The R2 of LASSO regression model and RF regression model are 0.6992 and 0.7946, respectively. The mean absolute error (MAE) and root mean square error (RMSE) of the LASSO regression model were 0.0268 and 0.043, respectively, and the MAE and RMSE of the RF prediction model were 0.0171 and 0.0355, respectively. In the RF model, and the weight of length of stay was the highest (0.730). Conclusions: The hospitalization expenses of patients with CRF are most affected by length of stay. The RF prediction model is superior to the LASSO regression model and can be used to predict the hospitalization expenses of patients with CRF. Health administration departments may consider formulating accurate individualized hospitalization expense reimbursement mechanisms accordingly.

Endocrine-disrupting chemicals in a typical urbanized bay of Yellow Sea, China: Distribution, risk assessment, and identification of priority pollutants.

Endocrine-disrupting chemicals (EDCs) in water are receiving particular attention as they pose adverse effects on aquatic systems, even at trace concentrations. A comprehensive study was conducted on 14 EDCs (five estrogens and nine household and personal care products (HPCPs)) in the water of the urbanized Jiaozhou Bay in the Yellow Sea during summer and winter. Results showed that the total concentration of 14 EDCs ranged from 100 to 658 ng L-1 and 56.7-212 ng L-1 in the estuarine and bay water, respectively. The average total concentration of five estrogens in summer was significantly (p < 0.05) lower than that in winter due to the higher precipitation dilution and degradations during summer, whereas the average total concentration of nine HPCPs was significantly (p < 0.05) higher during the summer than that during the winter because of the higher usage and emissions during the summer. Estrogens and HPCPs were dominated by 17α-ethinylestradiol and p-hydroxybenzoic acid (PHBA), respectively. High PHBA concentrations may be related to the hydrolysis of parabens. The total concentrations of EDCs were higher in the eastern coastal seawater of the bay due to the strong influence of domestic and industrial wastewater discharge. Estrogens may interfere with the endocrine system of aquatic organisms in the bay because the total estradiol equivalent concentration exceeded 1 ng L-1. 17α-ethinylestradiol was the main contributor to the estrogenic activity. The EDC mixtures posed high risks (RQ > 1) to mollusks, crustaceans, and fish, and low to moderate risks (RQ < 1) to algae. Fish was the most sensitive aquatic taxon to the EDC mixtures. Given the concentration and frequency of EDCs, the optimized risk quotient method revealed that 17α-ethinylestradiol, estrone, triclocarban, triclosan, and 17ß-estradiol should be prioritized in ecological management because of their high risks (prioritization index of >1).

Assessment of cadmium pollution and subsequent ecological and health risks in Jiaozhou Bay of the Yellow Sea.

Million tons of cadmium (Cd) are annually discharged into China's coastal regions, creating a persistent hazard to marine organisms and human health. This study assessed Cd residues in the Yellow Sea's semi-enclosed Jiaozhou Bay (JZB), finding concentrations of 0.05-0.94 µg/L in seawater and 0.03-0.18 mg/kg in sediment. For marine organisms, mollusks had the highest Cd concentration (0.44 ± 0.09 mg/kg), followed by crustaceans (0.26 ± 0.08 mg/kg) and fish (0.10 ± 0.02 mg/kg). Cd was clearly accumulated by mollusks, with biota-sediment accumulation factor (BSAF) values >1 and biota-water accumulation factor (BWAF) values >1000. Stable nitrogen isotope (δ15N) analysis showed that Cd underwent biomagnification in mollusks, but was significantly bio-diluted with increasing trophic level among other marine organisms. In general, Cd contamination levels were low in the JZB's seawater and sediment, and fish was estimated to be certainly polluted due to strict safety limitations on seafood in China. Current Cd residues mean that few aquatic species (<< 5%) would be affected by acute exposure, and ~ 10% of the species would be affected by chronic exposure. Based on target hazard quotients (THQ) and estimated weekly intakes (EWIs), urban residents around the JZB would experience higher health risks in comparison with rural residents due to higher seafood consumption rates, especially from mollusk consumption. Therefore, urban households in the area should increase their fish consumption rate and reduce that of mollusks.

Integrating hydrological, landscape ecological, and economic assessment during hydropower exploitation in the upper Yangtze River.

Comprehensive investigation of hydrological processes associated with landscape ecology and economic development plays a key role in watershed management, and is less developed in watersheds with large-scale cascade dams. With the abundant hydropower resources and its unprecedented advantages, hydropower exploitation in the upper Yangtze River (Jinsha River) is critical to energy structure adjustment in China. Therefore, we integrated hydrological modeling, landscape ecology analysis, and economic analysis in the dammed Jinsha River. With climate variations in the Jinsha River Basin, the average flow near the uppermost dams in the mainstream grew from 796 m3 s-1 (1990s), to 918 m3 s-1 (2000s), and further to 1025 m3 s-1 (2010s). During 1991 to 2017, the source power in the headwater region grew slightly, but varied little in the downstream area. In the lower dammed Jinsha River, analysis of landscape indicators showed that the landscape was enriched, while the landscape type distribution was more uniform. Moreover, hydropower exploitation brought benefits to regional economic development. Principal component analysis further highlighted the landscape ecological and economic variations with high loadings in the first principal component. With the non-significant temporal variations and normal spatial fluctuations in flow discharge, the landscape pattern was basically stable, and the utilization of hydropower can be sustainable in the Jinsha River. In addition, hydropower development drove local economic development. Based on the integrated analysis of hydrological, landscape ecological, and economic assessment at the watershed scale, our results stressed the significance of hydropower exploitation in the Jinsha River. However, more attention should be paid to the warming climate during hydropower exploitation. These findings are valuable for the scientific planning of hydropower bases in watersheds with large-scale cascade dams, and have substantial implications for sustainable hydropower development.

Multidimensional Feature Classification of the Health Information Needs of Patients With Hypertension in an Online Health Community Through Analysis of 1000 Patient Question Records: Observational Study.

BACKGROUND: With the rapid development of online health communities, increasing numbers of patients and families are seeking health information on the internet. OBJECTIVE: This study aimed to discuss how to fully reveal the health information needs expressed by patients with hypertension in their questions in a web-based environment and how to use the internet to help patients with hypertension receive personalized health education. METHODS: This study randomly selected 1000 text records from the question data of patients with hypertension from 2008 to 2018 collected from Good Doctor Online and constructed a classification system through literature research and content analysis. This paper identified the background characteristics and questioning intention of each patient with hypertension based on the patient's question and used co-occurrence network analysis and the k-means clustering method to explore the features of the health information needs of patients with hypertension. RESULTS: The classification system for the health information needs of patients with hypertension included the following nine dimensions: drugs (355 names), symptoms and signs (395 names), tests and examinations (545 names), demographic data (526 kinds), diseases (80 names), risk factors (37 names), emotions (43 kinds), lifestyles (6 kinds), and questions (49 kinds). There were several characteristics of the explored web-based health information needs of patients with hypertension. First, more than 49% of patients described features, such as drugs, symptoms and signs, tests and examinations, demographic data, and diseases. Second, patients with hypertension were most concerned about treatment (778/1000, 77.80%), followed by diagnosis (323/1000, 32.30%). Third, 65.80% (658/1000) of patients asked physicians several questions at the same time. Moreover, 28.30% (283/1000) of patients were very concerned about how to adjust the medication, and they asked other treatment-related questions at the same time, including drug side effects, whether to take the drugs, how to treat the disease, etc. Furthermore, 17.60% (176/1000) of patients consulted physicians about the causes of clinical findings, including the relationship between the clinical findings and a disease, the treatment of a disease, and medications and examinations. Fourth, by k-means clustering, the questioning intentions of patients with hypertension were classified into the following seven categories: "how to adjust medication," "what to do," "how to treat," "phenomenon explanation," "test and examination," "disease diagnosis," and "disease prognosis." CONCLUSIONS: In a web-based environment, the health information needs expressed by Chinese patients with hypertension to physicians are common and distinct, that is, patients with different background features ask relatively common questions to physicians. The classification system constructed in this study can provide guidance to health information service providers for the construction of web-based health resources, as well as guidance for patient education, which could help solve the problem of information asymmetry in communication between physicians and patients.

Cost-effectiveness of Medical Expulsive Therapy with ?-blockers for Large Distal Ureteral Stones in China.

PURPOSE: To assess the cost-effectiveness of medical expulsive therapy (MET) versus observation for large distal ureteral stones in China and provide preliminary evidence for the determination of the course of MET by mathematical estimation. MATERIALS AND METHODS: With linear success rate assumptions, a decision tree was constructed by TreeAge Pro 2011 software. The stones passage rates after observation or receiving 0.4 mg daily tamsulosin were estimated according to a large randomized clinical trial (RCT). The costs of ureteroscopy, drugs and examinations were estimated according to related price from pharmacies or hospitals, or the guidance price published by the government. MET was also compared with observation by the sensitivity analysis. The effectiveness of MET or observation was presented by quality-adjusted life-day. Mathematical estimation of stone expulsion time was made by using a decision-analytic Markov model under the assumption that the daily stone expulsion probability is constant. RESULTS: In China, the MET was associated with a $295.1 cost advantage over observation. The cost of ureteroscopy has to decrease to $77.8 to reach cost equivalence between observation and MET. Observation is cost-effective only if ureteroscopy is very cheap or the difference of stone expulsion rates is insignificant. The estimated expulsion time was much longer than those reported in above mentioned RCT. CONCLUSION: Due to the high cost of ureteroscopy, MET showed a cost advantage over observation in treating distal ureteral stones in China. The daily stone passage rate was inconstant. More studies are needed to find the appropriate duration of MET.

Occurrence and risk assessment of total mercury and methylmercury in surface seawater and sediments from the Jiaozhou Bay, Yellow Sea.

The Jiaozhou Bay is a semi-enclosed bay located in the middle of the Yellow Sea. Effluents from wastewater treatment plants have been carried into the bay, which has significantly increased the deposition of mercury. The spatial distributions of total mercury (THg) and methylmercury (MeHg) in dissolved state, in suspended matters of seawater and surface sediments at 26 locations inside the Jiaozhou Bay and five surrounding rivers in April 2018 were examined. The contents of THg and MeHg found along the eastern coast were higher than those found along the western coast, which indicated the impact of human activities (river input) on the Jiaozhou Bay. The partition coefficient (LogKd) was used to express the distribution relationships of THg and MeHg in suspended matters and dissolved state, and it was concluded that suspended matter was the main reservoir of mercury in Jiaozhou Bay seawater. The correlations between contents and physicochemical properties of seawater showed that THg and MeHg concentrations in seawater decreased with increasing salinity and pH. The effects of the mean grain diameter (MGD) and sediment organic matter (SOM) on the THg and MeHg in surface sediments were also discussed. Principal component analysis (PCA) was used to obtain the factors determining the methylation proportion in the surface sediments, indicating that the combination of human activities and natural processes affected the degree of methylation in the sediments. The spatial distribution of THg, MeHg and MeHg% was suggested to be disturbed by the interaction of natural processes and human activities (river input) by the correlation analysis of the corresponding pollutant concentrations among seawater and. Although the concentrations of THg and MeHg in seawater and sediments of the Jiaozhou Bay did not exceed the Chinese regulatory standards, the pollution levels of THg and MeHg were comparable to those in other bays in the world.

Elderly Health Inequality in China and its Determinants: A Geographical Perspective.

Inter-regional health differences and apparent inequalities in China have recently received significant attention. By collecting health status data and individual socio-economic information from the 2015 fourth sampling survey of the elderly population in China (4th SSEP), this paper uses the geographical differentiation index to reveal the spatial differentiation of health inequality among Chinese provinces. We test the determinants of inequalities by multilevel regression models at the provincial and individual levels, and find three main conclusions: 1) There were significant health differences on an inter-provincial level. For example, provinces with a very good or good health rating formed a good health hot-spot region in the Yangtze River Delta, versus elderly people living in Gansu and Hainan provinces, who had a poor health status. 2) Nearly 2.4% of the health differences in the elderly population were caused by inter-provincial inequalities; access (or lack of access) to economic, medical and educational resources was the main reason for health inequalities. 3) At the individual level, inequalities in annual income served to deepen elderly health differences, and elderly living in less developed areas were more vulnerable to urban vs. rural-related health inequalities.