Highest Contribution Rate Research Articles

Pollution Characteristics and Ecological Risk Assessment of Heavy Metals in Sediments of the Three Gorges Reservoir

In order to understand the spatial distribution and ecological risk of heavy metal pollution in the sediments of the Three Gorges Reservoir, surface sediment samples in six typical tributaries and estuaries were analyzed. The heavy metal content in sediment was detected by ICP-MS (PE Elan DRC Ⅱ, PerkinElmer, Waltham, MA, USA) after digestion by mixed acid. The data were evaluated and analyzed using multiple methods, including the potential ecological risk index, the geoaccumulation index (Igeo), and cluster analysis. The results show that the tributary surface sediments were polluted by heavy metals to a certain extent. Cu, Zn, Pb, and Cr have been enriched in sediments in recent years. The results of Igeo show that the pollution degree is as follows: Pb > Cu > Zn > Cr > Cd > Ni > As > Hg. According to the potential ecological risk index, the grades of Yunyang, Xiaojiang, and Xinjin are all medium risk, and Cd has the highest contribution rate. Combined with field investigation data, cluster analysis, and correlation analysis, we conclude that Cu, Zn, and Cr are likely to come from agricultural chemical fertilizers and industrial sewage, while Pb mainly comes from the discharge of ship fuel.

Acrylamide content of collected food products from Tehran's market: a risk assessment study.

Acrylamide concentration in food products collected from the Tehran market was investigated by the aid of a dispersive liquid-liquid microextraction (DLLME) system coupled with gas chromatography-mass spectrometry (GC-MS). Also, the dietary exposure distribution and related potential risk for acrylamide ingestion were estimated by the Monte Carlo simulation (MCS). The highest and lowest mean concentration of acrylamide was detected in coffee and roasted nuts samples as 549 and 133μg/kg, respectively. The mean acrylamide dietary exposure values for children (3-10years), adolescents (11-17years), adults (18-60years), and seniors (61-96years) were estimated to be 1.81, 1.02, 0.61, and 0.53μg/kg body weight (BW)/day, respectively. In all age groups, except children, the estimated exposure in men and boys was higher than that in women and girls. Bread, despite containing low acrylamide content groups (157μg/kg while compared with other, except roasted nuts), showed with the highest contribution rate in all age groups due to its high consumption rate. The estimated incremental lifetime cancer risk (ILCR) for all age groups was noted as greater than 10-4 indicating serious risk to the population. Moreover, the margin of exposure (MOE) values based on carcinogenicity showed health concern to all age groups (< 10,000). Regarding the non-carcinogenic risk, the target hazard quotient (THQ) was lower than 1, and MOE based on neurotoxicity was higher than 125 (safety thresholds), which represented negligible and ignorable risk in all age groups except in a small group of children and adolescents. Graphical abstract.

완전적립식 국민연금 재정 달성 가능성 분석

This paper studies the feasibility of fully funded scheme for National Pension Service. Taking 1) contribution rate, 2) pension fund performance, and 3) government subsidy as control variables, we apply linear programming techniques to identify optimal policy design to achieve long term financial goals of National Pension Service. The results are rather frightening. Had the pension policy been revised in 2015, the fully funded scheme can be achieved with a marginal increase of the contribution rate. However, in 2020, a very high contribution rate along with a sharp increase of investment risks and large amount of government subsidies are required to achieve the goals. If the pension reform is delayed by 2025, achieving fully funded scheme becomes infeasible.

Spatial and Temporal Variations of Potential Evapotranspiration in the Loess Plateau of China During 1960–2017

Potential evapotranspiration (ET0) is an integral component of the hydrological cycle and the global energy balance, and its long-term variation is of much concern in climate change studies. The Loess Plateau is an important area of agricultural civilization and water resources research. This study analyzed the spatial and temporal evolution processes and influential parameters of ET0 at 70 stations in different topographical areas of the Chinese Loess Plateau (CLP). Using the Mann–Kendall trend, Cross wavelet transform, and the ArcGIS platform, the ET0 of each station was quantified using the Penman–Monteith equation, and the effects of climatic factors on ET0 were assessed by analyzing the correlation coefficients and contribution rates of the climatic factors. The results showed that: (1) the overall trend of the ET0 in different terrains of the Loess Plateau is consistent, however, the ET0 values differ; the hill region (HR) has the highest ET0, followed by the valley region (VR), and the mountain region (MR) has the lowest, and ET0 changes differ between seasons. (2) Spatial distribution characteristics of multiyear mean ET0 in the study are as follows: the ET0 values in mountain and hilly areas are decreasing from west to east, and the higher mean annual ET0 value in the VR is mainly concentrated in the eastern CLP. (3) In the past 58 years, the annual mean and the seasonal ET0 of the region showed increasing trends, however, differences in different terrains were obvious. (4) ET0 has significant correlations with El Niño–Southern Oscillation (ENSO), Pacific–North American teleconnection (PNA), and Atlantic Multidecadal Oscillation (AMO). The resonance period of ET0 and ENSO was 3–6 a, mainly in 1976–1985. The mean coherence phase angle was close to 360°, indicating that ET0 lags behind PNA by approximately 2–6 a; ET0 has a very strong positive correlation with AMO. (5) Relative humidity (RH) is the main influencing factor of ET0 change in the Loess Plateau. Temperature (T) variation has the highest contribution rate (42%) to the regional ET0 variation in the entire CLP. We should pay more attention to the variation of evaporation under future climate change, especially temperature change.

Just-in-Time Learning-Based Soft Sensor for Mechanical Properties of Strip Steel via Multi-Block Weighted Semisupervised Models

Mechanical properties are important indexes to evaluate the quality of hot rolling strips. It is a research hotspot in the field of hot rolling that realizing timely and accurate soft sensing of mechanical properties. Traditional soft sensing methods have poor performance in the application of strong nonlinearity and multiple working conditions. Moreover, the utilization rate of data is relatively low, which limit the improvement of prediction accuracy. To solve the problems above, a just-in-time learning (JITL) based multi-block weighted semisupervised Gaussian mixture regression (JMWSSGMR) soft sensor is proposed in the paper. There are two stages in the soft sensor: off-line variable blocking and on-line local modeling. In the off-line phase, process variables are divided into different sub-blocks by partial least square (PLS) according to distinct principal component directions. In each sub-block, original variables with high contribution rate are retained. In the on-line phase, optimized Mahalanobis distance is constructed to select the most similar historical samples to the query sample. Next, various real-time semisupervised sub-models are built to estimate the output of the query sample. Finally, predicted values of sub-models are fused and ultimate prediction of mechanical properties is obtained. Case studies are carried out on a numerical example and a hot rolling process. The feasibility and effectiveness of proposed soft sensor are verified by the predicted results.

Application of GWO-SVM Algorithm in Arc Detection of Pantograph

High-speed train will produce pantograph arc during the driving process, which is harmful to pantograph-catenary system. In order to reduce pantograph-catenary system damage, a method based on Gray Wolf algorithm to optimize the binary Support Vector Machine classifier to identify pantograph arc is proposed. In this article, 5 groups of pantograph current experiments under different conditions are carried out, and the current data in the pantograph-catenary system under different conditions are measured. The current data state obtained from the pantograph experiments is divided into normal current state and arc current state. Select the mean value, variance, standard deviation, mean value of the first-order difference, and mean value of the second-order difference of the current data as the characteristic value of the pantograph current, and calculate the contribution rate of each characteristic value at the same time, then the current eigenvalue data with a high contribution rate is used as a training sample for learning and recognition through the classifier optimized by Gray Wolf algorithm. The experimental results show that the Gray Wolf optimization algorithm can quickly and accurately identify the pantograph arc, and the classification model obtained is more accurate than the commonly used optimization algorithms such as genetic algorithm and particle swarm. In addition, an engineering implementation of on-line identification of pantograph arc based on industrial computer is proposed.

Occurrence, source estimation and risk assessment of pharmaceuticals in the Chaobai River characterized by adjacent land use

This study investigated the occurrence of 27 pharmaceuticals with diverse physicochemical properties in a year-long monitoring campaign in the Chaobai River, China. The correlation between the distribution of pharmaceuticals in the river and the adjacent sources was elucidated. The results indicate that the agriculture area was the most polluted area with a median summed pharmaceutical concentration of 225.3 ng L−1, followed by the urban area and the mountain area with the corresponding values of 136.9 and 29.9 ng L−1, respectively. In terms of individual compounds, 22 out of 27 compounds were detected with concentrations ranging from <1 to 1972 ng L−1. Caffeine, carbamazepine, azithromycin, bezafibrate, metoprolol, sulfadiazine, sulfamethoxazole, clarithromycin, erythromycin, roxithromycin, and trimethoprim were pharmaceuticals with relatively high levels, with median concentrations ranging from 3.3 to 25.6 ng L−1 and detection frequencies ranging from 40% to 97%. Higher concentrations were mainly observed during cold seasons, with mean concentrations 1 to 52 times as high as those during warm seasons. Spatial analysis reveals that the pharmaceutical concentrations in different areas were impacted by different sources. A wastewater treatment plant was an important source in the urban area, while the agriculture area was impacted by various treated and untreated wastewater sources. The species sensitivity distribution model and risk quotient (RQ) method were combined in the ecological risk assessment. The results indicate that the multi-substance potentially affected fraction (msPAF) values of the sampling sites were below 0.04%, whereas nearly half of RQ values were higher than 1. Caffeine was proposed as a priority compound due to its high contribution rate (i.e., 79%) to the cumulative msPAF value, which implies that increased control and management of untreated wastewater sources along the Chaobai River is necessary.

Browning and Flavor Changing of Cloudy Apple Juice during Accelerated Storage

In this paper, the browning and flavor changing of cloudy apple juice during accelerated storage were investigated with storage temperature at 37 °C. These indicators, such as, soluble solids content, titratable acid content, Vc, color difference, and turbidity of cloudy apple juice were measured every 1 or 2 hours during storage. Meanwhile, the volatile flavor of juice were also analyzed using electronic nose. The results showed that L* and ΔE* values decreased during storage, while a* and b* values increased. The electronic nose could distinguish the apple juice stored for 0 hour from other storage time, and the sensor with the highest contribution rate was W1S, followed by W1C and W2S, which were sensitive to hydrocarbons, aromatics, and alcohols, respectively. The values of Vc content, sugar-acid ratio, and turbidity fluctuated slightly during storage. In general, the content of Vc decreased significantly, and the ratio of sugar to acid also decreased, while, turbidity increased during storage.

Distributional effects of social security reforms: The case of France

AbstractThis paper assesses the impact of two social security reforms using a calibrated, dynamic life cycle model. It quantifies the long‐run distributional impact of two sets of reforms in France: (1) the 2013 reform of Prime Minister Ayrault, which modified the parameters of a defined benefit (DB) plan, and (2) a hypothetical reform that changes the system to a notional defined contribution (NDC) plan, similar to that in Italy. First, on aggregate welfare, the Ayrault reform and the hypothetical switch to NDC yield contrasting results. The Ayrault reform improves aggregate welfare, which is not the case for the NDC reform. Welfare comparisons are made with respect to the “benchmark economy,” where increases in life expectancy occur and are dealt with only through a higher contribution rate. Second, both reforms yield unequal distributions of welfare changes, with low‐skill workers on the losing end. Under the Ayrault reform, low‐skill workers delay retirement by two years, to age 62. Under NDC reform, pensions for low‐skill workers fall substantially as inequalities during the work life translate directly into inequalities in pensions. The switch to an NDC scheme leads to a more unequal society in terms of asset and welfare distribution.

Identifying the limiting factors driving the winter wheat yield gap on smallholder farms by agronomic diagnosis in North China Plain

North China Plain (NCP) is the primary winter wheat production region in China, characterized by smallholder farming systems. Whereas the winter wheat average yield of smallholder farmers is currently low, the yield potential and limiting factors driving the current yield gap remain unclear. Therefore, increasing the wheat yield in NCP is essential for the national food security. This study monitored wheat yield, management practices and soil nutrient data in 132 farmers' fields of Xushui County, Baoding City, Hebei Province during 2014–2016. These data were analyzed using variance and path analysis to determine the yield gap and the contribution of yield components (i.e., spikes per hectare, grain number per spike and 1000-grain weight) to wheat yield. Then, the limiting factors of yield components and the optimizing strategies were identified by a boundary line approach. The results showed that the attainable potential yield for winter wheat was 10 514 kg ha−1. The yield gaps varied strongly between three yield groups (i.e., high, middle and low), which were divided by yield level and contained 44 farmers in each group, and amounted to 2493, 1636 and 814 kg ha−1, respectively. For the three yield components, only spikes per hectare was significantly different (P<0.01) among the three yield groups. For all 132 farmers' fields, correlation between yield and spikes per hectare (r=0.51, P<0.01), was significantly positive, while correlations with grain number per spike (r=−0.16) and 1000-grain weight (r=−0.10) were not significant. The path analysis also showed that the spikes per hectare of winter wheat were the most important component to the wheat yield. Boundary line analysis showed that seeding date was the most limiting factor of spikes per hectare with the highest contribution rate (26.7%), followed by basal N input (22.1%) and seeding rate (14.5%), which indicated that management factors in the seeding step were the most important for affecting spikes per hectare. For desired spikes per hectare (>6.598 × 06 ha−1), the seeding rate should range from 210–300 kg ha−1, seeding date should range from 3th to 8th October, and basal N input should range from 90–180 kg ha−1. Compared to these reasonable ranges of management measures, most of the farmers' practices were not suitable, and both lower and higher levels of management existed. It is concluded that the strategies for optimizing yield components could be achieved by improving wheat seeding quality and optimizing farmers' nutrient management practices in the NCP.

Analisis Kontribusi Pajak Daerah Jakarta Utara Terhadap Penerimaan Pajak Daerah Dki Jakarta

This study aims to determine the level of the contribution of hotel tax, restaurant tax, entertainment tax, advertisement tax and parking tax on local tax revenues in Suku Badan Pajak dan Retribusi Daerah Kota Administrasi Jakarta Utara (Period 2012-2016). This research uses descriptive analysis method. The data collection technique is interview and documentation in the form of goals and realizations from the hotel tax, restaurant tax, entertainment tax, advertisement tax and parking tax in Suku Badan Pajak dan Retribusi Daerah Kota Administrasi Jakarta Utara from 2012 until 2016.The results of the study show that the percentage of hotel tax, advertisement tax and parking tax in the North Jakarta area to DKI Jakarta local tax revenues are still in a very less category, which is below 10%, while the contribution of restaurant tax is in the less category with a percentage of 10.10 - 20%, the highest contribution rate is entertainment tax which is in the medium category with a percentage of 20.10 - 30%.

Peatland degradation reduces methanogens and methane emissions from surface to deep soils

Abstract Peatland degradation is expected to increase the rate of aerobic decomposition in surface soil (0–30 cm). Carbon stored in both the subsurface (30–60 cm) and deeper layers (>60 cm) of peatlands is also expected to be metabolized after degradation. However, little is known about how methane were emissions from subsurface and the deeper layers of peatlands during degradation. Three peatland degradation stages: S1, intact fen with high water table; S2, lightly degraded fen with a fluctuating water table; S3, heavily degraded fen with a lower water table were chosen to quantify the differences in CH 4 emissions at different peatland degradation stages. CH 4 emissions and methanogens of subsurface and deep soil were also measured to reveal the contribution rates of subsurface methane emission in this study. After four-years experiment, we found that the abundance of methanogens and methane emissions decreased as peatlands were more heavily degraded. We also found that the contribution rate of methane emission decreased from peat surface to subsurface and deep layer, and this trend varied with peatland degradation. A higher contribution rate was found in the subsurface methane emissions from S1 (32.63%) and S2 (19.94%). Importantly, when peatlands were heavily degraded, the subsurface changed from a CH 4 source to a sink. Decreased methane emissions of the degraded peatlands was also associated with a high abundance of methanogens (R 2 = 0.75, p

Integrating GWAS, QTL, mapping and RNA-seq to identify candidate genes for seed vigor in rice (Oryza sativa L.)

Seed vigor is an important seed quality trait in rice (Oryza sativa L.) that profoundly affects seedling morphogenesis in different environments. Generally, highly vigorous seeds have many advantages in agricultural production, such as resistance to adverse stresses, rapid emergence, and yield improvement. In the present study, one germplasm collection and one recombinant inbred line (RIL) population were used to identify quantitative trait loci (QTLs) for seed vigor. A total of 19 single nucleotide polymorphisms (SNPs) were found to be significantly associated with seed vigor (−log10(P) > 6) in the germplasm collection, which consisted of 200 rice cultivars. Nine loci responsible for seed vigor were identified via QTL mapping by using a high-density bin map. To screen the candidate genes more efficiently, we selected six loci that were co-localized in GWAS and QTL mapping, overlapped previous reports, repeat detected across two seasons, or high contribution rate as reliable loci. A total of 44 differentially expressed genes were obtained from the reliable loci via gene expression profile analysis. Among these 44 genes, Os06g0108600, Os06g0110200, Os06g0253100, Os06g0282000, Os07g0583600, Os07g0592600, and Os09g0432300 were the most promising candidates associated with seed vigor.

Non-point source pollution estimation in the Pingqiao River Basin, China, using a spatial hydrograph-separation approach

ABSTRACTFor efficient and targeted management, this study demonstrates a recently developed non-point source (NPS) pollution model for a year-long estimation in the Pingqiao River Basin (22.3 km2) in China. This simple but physically reasonable model estimates NPS export in terms of land use by reflecting spatial hydrological features and source runoff measurements under different land-use types. The NPS export was separately analysed by a distributed hydrological model, a spatial hydrograph-separation technique, and an empirical water quality sub-model. Simulation results suggest that 57 890 kg of total nitrogen (TN) and 1148 kg of total phosphorus (TP) were delivered. The results, validated with observed stream concentrations, show relative errors of 23.3% for TN and 47.4% for TP. Countermeasures for urban areas (5.3% of total area) were prioritized because of the high contribution rate to TN (14.1%) and TP (26.2%) which is caused by the high degree of runoff (8.5%) and pollution source.

A Calculation Model for CO2 Emission Reduction of Energy Internet: A Case Study of Yanqing

This paper takes the regional energy internet as the research object, and combines the power system, primary energy system, transportation system, and thermal energy system to give the system boundary. First, the mathematical decomposition method and the logical integration method were combined to decompose the total low-carbon capability into seven single low-carbon capabilities. On the basis of the mechanism of carbon emission reduction, a comprehensive calculation model for CO2 emissions reduction of the energy internet was then established. Finally, taking the Yanqing Energy Internet Demonstration Zone in China as an example, it was calculated that the model could reduce CO2 emissions by 14,093.19 tons in 2025. The results show that the methods adopted in this paper avoided the overlap calculation reasonably well; the comprehensive calculation model of CO2 emissions reduction has strong versatility, and can quantitatively calculate the carbon emission reduction amount for any completed or planned energy internet. Among the seven low-carbon capabilities, “replacement of gasoline with electricity” had the highest contribution rate, with a value of 42.62%, followed by “renewable energy substitution” (37.13%). The innovations in this paper include: (1) The problem of reasonable splitting of the overlapping parts in carbon emission reduction calculations being solved. (2) The first comprehensive calculation model of CO2 emission reduction on the energy internet being established. (3) The contribution of the seven low-carbon capabilities of the energy internet to total emissions reduction being clarified.

Spatiotemporal Variability and Source Apportionment of Soil Heavy Metals in a Industrially Developed City

In the present study, a total of 1130 soil samples were collected in 2003 and 2013 in the Ningbo city district, and the content of eight typical heavy metals were measured. The degree of heavy metal pollution in the soil in the study area was evaluated using the pollution index evaluation method. The temporal and spatial variation in the pollution were analyzed by the geostatistics method, and principal component analysis (PCA) and the UNMIX model were used to analyze the heavy metal pollution sources. The results showed that:① excluding As, the mean values of the other seven heavy metals in both periods exceeded the soil background values in Zhejiang province and national background values, which indicated that heavy metal pollution is common in the soil from the study area. From 2003 to 2013, the mean content of all elements increased to some degree, indicating that the heavy metals pollution was generally aggravated in 10 a; the increase in the mean Hg content was the greatest. ② The evaluation results based on the single-factor pollution index showed that the pollution degree was high for Hg; moderate for Cd, Cu, and Pb; slight for Zn, Cr, and Ni; and unpolluted for As. The evaluation results based on Nemero's comprehensive pollution index showed that the pollution index for all samples exceeded the precaution value, and the number of soil samples that were characterized as heavily polluted with a comprehensive pollution index over 3 had increased significantly. ③ The spatial distribution of the same heavy metal in different periods presented similar characteristics. Generally speaking, the spatial distribution of Pb was similar to that of Hg, and the spatial distributions of Cr, As, Cu, Zn, and Ni were similar to each other; high value areas were mainly concentrated in the four areas of Haishu, Jiangbei, Jiangdong, and Zhenhai districts, where the polluted enterprises were densely distributed and human activities were frequent. ④ Based on PCA and the UNMIX receptor model, the source analysis results of soil heavy metals in 2013 were essentially the same, i.e., the source of heavy metal pollution in the study area included industrial sources and living sources. Industrial sources of heavy metal pollution had the highest contribution rate and derived from industrial wastewater, waste gas, and waste residue discharged by plasticizing, mining, and metallurgical enterprises; chemical and mechanical manufacturing enterprises; etc., causing the accumulation of Cr, As, Cu, Zn, and Ni in the soil. The living sources had the second highest contribution rate and originated from the pollution of particulates and dust caused by domestic waste, automobile exhaust, and road wear. Additionally, natural factors had small contribution rates, mainly due to the spread of pollutants by prevailing winds and atmospheric settlement.

Prediction of Changes in Habitat Distribution of the Alfalfa Weevil (Hypera postica ) Using RCP Climate Change Scenarios

Climate change can affect variables related to the life cycle of insects, including growth, development, survival, reproduction and distribution. As it encourages alien insects to rapidly spread and settle, climate change is regarded as one of the direct causes of decreased biodiversity because it disturbed ecosystems and reduces the population of native species. Hypera postica caused a great deal of damage in the southern provinces of Korea after it was first identified on Jeju lsland in the 1990s. In recent years, the number of individuals moving to estivation sites has concerned scientists due to the crop damage and national proliferation. In this study, we examine how climate change could affect inhabitation of H. postica. The MaxEnt model was applied to estimate potential distributions of H. postica using future climate change scenarios, namely, representative concentration pathway (RCP) 4.5 and RCP 8.5. As variables of the model, this study used six bio-climates (bio3, bio6, bio10, bio12, bio14, and bio16) in consideration of the ecological characteristics of 66 areas where inhabitation of H. postica was confirmed from 2015 to 2017, and in consideration of the interrelation between prediction variables. The fitness of the model was measured at a considered potentially useful level of 0.765 on average, and the warmest quarter has a high contribution rate of 60-70%. Prediction models (RCP 4.5 and RCP 8.5) results for the year 2050 and 2070 indicated that H. postica habitats are projected to expand across the Korean peninsula due to increasing temperatures.

Interactive impacts of climatic, hydrologic and anthropogenic activities on watershed health

The current study aimed to comprehensively assess the potential watershed health (WH) using an adapted reliability, resilience and vulnerability (RelResVul) framework for the 24 sub-watersheds of Shazand, Markazi Province, Iran. Towards this goal, the appropriate criteria and acceptable corresponding thresholds were adapted to calculate the main WH indictors of reliability (Rel), resilience (Res) and vulnerability (Vul). Accordingly, the RelResVul framework was conceptualized and customized for five criteria of standardized precipitation index (SPI), normalized difference vegetation index (NDVI), soil erosion, and low and high flow discharges. The effect sizes of used criteria and indicators on the Shazand WH status were also determined. Consequently, the status of Rel, Res and Vul indicators and integrated WH status were mapped for four years of 1986, 1998, 2008 and 2014 and for the whole watershed by developing an integrated watershed health index (IWHI). Finally, the change detection approach was applied to determine the trend of changes in IWHI during last three decades. The results approved the high variability in effectability of Rel, Res and Vul indicators and integrated health status of the Shazand Watershed from the selected criteria in study four years. The results revealed that in the all study years, the Rel indicator almost had the higher contribution rate (≥34%) in the Shazand WH. None of sub-watersheds in the study years were assessed in a healthy status in terms of IWHI based on the RelResVul framework. In terms of WH change detection over the study periods, WH was found to declining by some 4% in the periods of 1986–1998 and 1986–2008 due to impact of industrialization and urban development. Whilst, the health status was non-significantly improved in other study periods. The present procedure can be supposed as a screening tool for a directive and efficient management of the watersheds.

Spatio-Temporal Patterns and Environmental Risk of Endocrine Disrupting Chemicals in the Liuxi River

This study aimed to investigate the occurrence and spatio-temporal distribution of 4-tert-octylphenol (4-t-OP), 4-nonylphenol (4-NP), triclosan (TCS), estrone (E1), 17β-estradiol (E2), and bisphenol-A (BPA) as endocrine disrupting chemicals (EDCs) in the water of the Liuxi River and to evaluate the risks for estrogenic activity. The results showed that EDCs had been detected at the 14 monitoring sites and the total concentration ranged from 26.07 ng·L-1 to 7109.5 ng·L-1, with the highest contribution rate coming from 4-NP (78.62%), followed by BPA (11.91%), and the other four EDCs (≤ 4.92%). On a spatial and temporal scale, the EDC contents increased longitudinally from upstream to downstream, especially in the heavily-polluted Baiyun section where the water quality was lower than level Ⅴ. The EDC contents in the tributaries were much higher than those in the main channels. Influenced by the monsoon precipitation, the contents of 4-NP, 4-t-OP, and total EDCs in the rainy season were significantly (P<0.05) higher than those in the dry season, while the seasonal changes of E1 and E2 followed the opposite tendency. A Pearson correlation analysis showed that DO was significantly negatively correlated with all the EDCs, suggesting that the EDCs and reductive organic pollutants might coexist. As TN, TP, NH4+-N, permanganate index, and EC were significantly positively correlated with E1, E2, BPA, and TCS but not obviously correlated with 4-NP (P>0.05), we presumed that the pollution source of E1, E2, BPA, and TCS might be the same with nitrogen and phosphorus nutrition, originating from the point source emission of the domestic sewage, industrial, and agricultural wastewater. In contrast, 4-NP and 4-t-OP more likely originated from the non-point source pollution from agriculture. RDA results showed that the variation of the EDCs contents by season was more obvious than that in space (RDA1 56.14%>RDA2 14.20%), which was much more influenced by 4-NP in the rainy season and by BPA in the dry season. As E1, E2, and TCS were positively correlated with the Cu, Zn, cyanide, and fecal coliform, these three target compounds could be used to indicate the multiple pollution components for water quality. Compared with the worldwide reported EDC contents in waters, 4-NP, BPA, and TCS contents in the middle and lower reaches of the Liuxi River were at higher levels, while E1, E2, and 4-t-OP were at the middle and lower levels. The risk assessment for estrogenic activity showed that the RQ values in the middle and lower reaches of the Liuxi River were all greater than 1, indicating that the downstream river sections were under high risk for estrogenic activity. As a result, appropriate precautions are needed to improve environmental management.

Research on coupling relationship between environmental quality and regional economic growth based on VAR model

In recent years, China has a rapid economic growth and development, especially in the Beijing-Tianjin-Hebei Region, the Yangtze River Delta Region and the Pearl River Delta Region. However, some areas also paid a heavy price: the destruction of environmental quality. In this study, taking the data in the Beijing-Tianjin-Hebei Region as example, the coupling model for the economic growth and the environmental quality is built to the analyze the change of the static relationship between the two; a VAR model is built to analyze the dynamic effect relationship between the economic growth and environmental quality. The main conclusion includes: (1) in the Beijing-Tianjin-Hebei Region, the economic growth is steady while the environmental quality is improved circuitously, so seeing from the relative angle, the relationship between economic growth and the environmental quality presents a “inverted U shape”. (2) A co-integration relationship exists between the regional economic growth and environmental quality, and an interactional relationship exists between the economic growth and environmental quality. (3) The impulse response of environmental quality on the economic growth has a short time and small amplitude; the economic growth has a low fluctuant contribution rate on the environmental quality, and the economic growth has a relatively small influence power on the environmental quality. (4) The economic growth has a direct impulse on the environmental quality with long response time and large amplitude; the environmental quality has a high fluctuant contribution rate on the economic growth, and the environmental quality can significantly promote the economic growth.