Ecosystem health of the Beiyun River basin (Beijing, China) as evaluated by the method of combination of AHP and PCA.

Ecosystem services provided by river ecosystems rely on healthy ecosystem structure and ecological processes. The Beijing-Tianjin-Hebei urban is a typical water-deficient area. As an important part of the urban-rural integration construction, evaluating the health status of the Beiyun River Basin and discovering the weak links in the water environment are the basis for improving the health of the basin. In this study, analytic hierarchy process (AHP) was used to establish an evaluation index system for the Beiyun River Basin from 5 aspects including water quality, biology, ecology, hydrology, and social functions, and the principal component analysis (PCA) was then used to assign weights to the index layer. The evaluation results showed that the health evaluation results of the Beiyun River Basin in 2019 are "sub-healthy," and the overall health status is getting worse from northwest to southeast. In the middle reaches of the region, the evaluation result is "healthy," followed by the upstream, and the downstream is the worst. The results showed that areas with less human interference or orderly intervention are in better health. High eutrophication level, low bio-diversity, and low vegetation coverage are the main indicators that leads to poor ecosystem health in the Beiyun River Basin. For the comprehensive management of the Beiyun River, the improvement of water quality and habitat ecological restoration are key actions to the health of the upstream ecosystem. The improvement of the health status of the downstream should focus on equal emphasis on water quality and quantity, restoration of biodiversity, and improvement of the quality of the riparian ecological environment.

An integrated assessment system for the carrying capacity of the water environment based on system dynamics.

Implementing an integrated assessment system for the carrying capacity of water environments should include recognizing and eliminating warning signs based on future predictions. However, existing methodologies tend to ignore the warning methods already in place, and current studies fail to quantify water ecology issues adequately. To help solve these problems, the ecological footprint that involves water uses a procedural indicator system, which adopts an early warning methodology system approach. This reconstruction has devised definitions, recognizes hazards, states forecasts status, analyses signs, judges situations, distinguishes levels, and eliminates risks. Based on these procedures, a dynamic system model has been developed, comprising five subsystems with an overarching parent system. These subsystems are population, ecology, water resources, water environment, and water ecology. The simulation involves carrying rates for the water environment, water resource, water ecology, and the level of harmony between society and the environment. All these serve to describe the water environment carrying capacity, i.e., the upper limit of the capacity to supply resources, remove pollutants, and offer sustainable ecological services. To properly quantify the carrying capacity, the water environment carrying rate was assessed by a comprehensive analysis of the water environment, water resources, and water ecological carrying rate. The carrying rates were calculated as the ratios of currently existing pressure to the maximum pressure that can be born. When values are greater than 1, they indicate overload because the actual pressure is greater than the pressure they can bear. The degree of coordination between economy and environment was standardized to range between 0 and 1. The larger the value, the more harmonious the relationship. For this research, the North Canal basin, a basin consisting of several rivers flowing through Beijing, Tianjin, and Hebei in northern China and its surrounding areas, was chosen. The results showed that water environment and resource carrying rates would decline to 2.60 and 0.94, respectively, while the water ecology carrying rate would remain high at 10.98 by the year 2025. In addition, the degree of coordination would increase from 0.65 to 0.79. These statistics mean that the overload statuses will be high for a long time, although they are expected to ease gradually. Besides, the relationship between society and the environment would become more stable. Considering both the overload statuses and the relationship between society and the environment, the warning signs would not vanish. Based on predictions, the measures used were explained from three perspectives, i.e., alleviating pressures, enhancing carrying capacities, and finding a balance between society and the environment. Finally, the effects of the measures were estimated quantitatively.

Health risk assessment based on source identification of heavy metals: A case study of Beiyun River, China.

Long-term retention and accumulation of heavy metals in rivers pose a great threat to the stability of ecosystems and human health. In this study, Beiyun River was taken as the example to quantitatively identify pollution sources and assess the pollution source-oriented health risk. A total of 8 heavy metals (Mn, Ni, Pb, Zn, As, Cr, Cd, and Cu) in Beiyun River were measured. Ordinary kriging (OK) and inverse distance weight (IDW) methods were used to predict the distribution of heavy metals. The results showed that the OK method is more accurate, and heavy metal pollution in the midstream and downstream is much more serious than that in the upstream. Principal component analysis-multiple linear regressions (PCA-MLR) and positive matrix factorization (PMF) methods were used to quantitatively identify pollution sources. The coefficient of determination (R2) of PMF is closer to 1, and the analyzed pollution source is more refined. Furthermore, the result of source identification was imported into the health risk assessment to calculate the hazard index (HI) and carcinogenic risk (CR) of various pollution sources. The results showed that the HI and CR of As and Ni to local residents were serious in the Beiyun River. Industrial activities (23.0%) are considered to be the largest contribution of heavy metals in Beiyun River, followed by traffic source (17%), agricultural source (16%), and atmospheric deposition (16%). The source-oriented risk assessment indicated that the largest contribution of HI and CR is agricultural source in the Beiyun River, followed by industrial activities. This study provides a "target" for the precise control of pollution sources, which is of great significance for improving the fine management of the water environment in the basin.

Evaluating surface water quality using water quality index in Beiyun River, China.

The Beijing-Tianjin-Hebei urban agglomeration is one of the most water-scarce regions in China, because of the frequent human activities. Water scarcity and pollution have weakened the service functions of water ecosystems and hindered the regional economic development. As the "lifeline" of the economic development of Beijing-Tianjin-Hebei region, the water quality of Beiyun River has been widely concerned. River water quality assessment is one of the most important aspects to enhance water resources management plans. Water quality index (WQI), as one of the most frequently used evaluation tools, was used to comprehensively analyze the water quality in the Beiyun River. Between January 2017 and October 2018, we collected samples from 16 typical sampling sites along the main rivers of the watershed, covering four seasons. Seventeen water quality parameters, including temperature, pH, conductivity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), total phosphorus (TP), oil, volatile phenol (VP), fluoride, sulfide, surfactant, lead (Pb), copper (Cu), zinc (Zn), and arsenic (As), were used to calculate WQI. The average WQI values of Beiyun River in winter, spring, summer, and autumn were 88.15, 71.70, 78.92, and 90.12, respectively, explaining the water quality was "good" generally. There were significant differences in the spatial distribution of WQI values from Beiyun River, and water quality of upstream and downstream was better than that of midstream. In addition, correlation analysis was applied to explore the correlation between land use types and water quality. Water quality was significant negatively correlated with agriculture land and rural residential land, and a positive relationship between urban land and water quality. Generally, we believe that people's related activities on different land use are major elements impacting the water quality. Water environment improvement ought to increase the wastewater collection rate and sewage treatment capacity in rural areas, especially in the midstream of the Beiyun River. Graphical abstract.

Chronic brain toxicity response of juvenile Chinese rare minnows (Gobiocypris rarus) to the neonicotinoid insecticides imidacloprid and nitenpyram.

Imidacloprid and nitenpyram are widely used neonicotinoid pesticides worldwide and were observed to adversely affect non-target aquatic organisms. In this study, the toxic effect of imidacloprid and nitenpyram on the brain of juvenile Chinese rare minnows (Gobiocypris rarus) was investigated by determining the oxidative stress, 8-hydroxy-2-deoxyguanosine (8-OHdG) content and acetylcholinesterase (AChE) activity. The superoxide dismutase (SOD) activities did not significantly change after long-term exposure to imidacloprid and nitenpyram. A noticeable increase of catalase (CAT) activities was observed on the brain tissues under 0.1 mg/L imidacloprid and under all nitenpyram treatments (p < 0.05). The malondialdehyde (MDA) content increased markedly under 2.0 mg/L imidacloprid and 0.1 mg/L nitenpyram treatments (p < 0.05). The glutathione (GSH) content in the brain significantly increased under 0.5 and 2.0 mg/L imidacloprid (p < 0.05). A significant decrease was observed in the mRNA levels of Cu/Zn-sod under 2.0 mg/L imidacloprid and those of cat under 0.1 and 0.5 mg/L nitenpyram (p < 0.05). The mRNA levels of gpx1 clearly decreased under 2.0 mg/L imidacloprid and under 0.1 mg/L nitenpyram (p < 0.05). The treatments of 0.1 and 0.5 mg/L nitenpyram decreased cat expression levels markedly (p < 0.05). 2.0 mg/L imidacloprid raised the 8-OHdG content. The AChE activities increased markedly under 0.5 and 2.0 mg/L imidacloprid while clearly decreasing under 2.0 mg/L nitenpyram (p < 0.05). Therefore, our results indicate that imidacloprid and nitenpyram might cause adverse effects on juvenile Chinese rare minnows brain. Notably, imidacloprid had greater impacts on juvenile rare minnows compared to nitenpyram.

Adsorption and regeneration of expanded graphite modified by CTAB-KBr/H3PO4 for marine oil pollution.

The cleaning-up of viscous oil spilled in ocean is a global challenge, especially in Bohai, due to its slow current movement and poor self-purification capacity. Frequent oil-spill accidents not only cause severe and long-term damages to marine ecosystems, but also lead to a great loss of valuable resources. To eliminate the environmental pollution of oil spills, an efficient and environment-friendly oil-recovery approach is necessary. In this study,1expanded graphite (EG) modified by CTAB-KBr/H3PO4 was synthesized via composite intercalation agents of CTAB-KBr and natural flake graphite, followed by the activation of phosphoric acid at low temperature. The resultant modified expanded graphite (M-EG) obtained an interconnected and continuous open microstructure with lower polarity surface, more and larger pores, and increased surface hydrophobicity. Due to these characteristics, M-EG exhibited a superior adsorption capacity towards marine oil. The saturated adsorption capacities of M-EG were as large as 7.44  g/g for engine oil, 6.12 g/g for crude oil, 5.34 g/g for diesel oil and 4.10 g/g for gasoline oil in 120min, exceeding the capacity of pristine EG. Furthermore, M-EG maintained good removal efficiency under different adsorption conditions, such as temperature, oil types, and sodium salt concentration. In addition, oils sorbed into M-EG could be recovered either by a simple compression or filtration-drying treatment with a recovery ratio of 58-83%. However, filtration-drying treatment shows better performance in preserving microstructures of M-EG, which ensures the adsorbents can be recycled several times. High removal capability, fast adsorption efficiency, excellent stability and good recycling performance make M-EG an ideal candidate for treating marine oil pollution in practical application.

At room temperature in water: efficient hydrogenation of furfural to furfuryl alcohol with a Pt/SiC-C catalyst.

Selective hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) is challenging because of many side reactions. The highly selective hydrogenation of FAL to FOL can be achieved over a Pt catalyst supported on nanoporous SiC-C composites even at room temperature in water. A Pt/SiC-C-200-H2 catalyst, which had a Pt loading of 3 wt% and was reduced in flowing hydrogen at 500 °C after calcination in air at 200 °C for 2 h, furnished complete FAL conversion and over 99% selectivity to FOL at 25 °C under 1 MPa of hydrogen in water. The kinetic behaviour of the selective hydrogenation of FAL to FOL with the 3 wt% Pt/SiC-C-200-H2 catalyst was also investigated and the turnover frequency (TOF) reached 1148 h-1. Moreover, the Pt/SiC-C catalyst is more active than other Pt catalysts supported on ordered mesoporous carbon CMK-3, activated carbon, periodic mesoporous silica SBA-15 or Al2O3. Detailed characterization using XRD, N2-sorption, SEM, TEM and XPS techniques reveals that the striking performance of the Pt/SiC-C catalyst can be attributed to the optimal metal-support interaction and the interfacial effect.

Impacts of sanitation upgrading to the decrease of fecal coliforms entering into the environment in China.

Identifying the sanitation efficacy of reducing fecal contaminations in the environment is important for evaluating health risks of the public and developing future management strategies to improve sanitation conditions. In this study, we estimated the fecal coliforms (FC) entering into the environment in 31 provinces in China under three sanitation scenarios. Our calculation results indicated that, the current FC release is disparate among regions, and the human releases in the rural regions were dominant, accounting for over 90% of the total human releases. Compared with the human release, the FC release from the livestock was of similar magnitude, but has a quite different spatial distribution. In China Women's Development Program, the Chinese government set the target to make over 85% of the population in the rural access to the toilets in 2020. If the target set by the Chinese government is achieved, a decrease of 34% (12-54%) in the FC releases would be anticipated. In the future, the improvement in sanitation and accesses to the safe drinking water in the less developed regions, such as Tibet, Qinghai, and Ningxia, should be considered as a priority.

Riverine nitrogen loss in the Tibetan Plateau and potential impacts of climate change.

The Tibetan Plateau (TP) has been the subject of study on water circulation and global climate change. Given the environmental processes related to water outflows, there could be massive nutrient losses in the land surface of TP. In this study, we analyzed the nitrogen discharges of the major rivers flowing out of the TP based on the 5-year monitoring data. According to our calculation, the majority of nitrogen outflows were discharged through the upper Yangtze River and upper Huanghe River, representing ~29% and ~17% of total riverine outflows, respectively. In the entire nitrogen deficit in TP land surface, about 2.7 × 10(5)Mg/year was lost through riverine discharges. Due to the global warming, the changes of hydrologic processes in TP would possibly accelerate the riverine nitrogen outflows in the future.

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006-2012).

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 10(5), 3.1 × 10(6) and 2.8 × 10(5) tons, respectively, while in 2006, the nutrient load was 7.4 × 10(5), 2.2 × 10(6) and 1.6 × 10(5) tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 10(5) tons), 70% of TN (2.2 × 10(6) tons) and 87% of TP (2.5 × 10(5) tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger.

[Spatial discharge characteristics and total load control of non-point source pollutants based on the catchment scale].

Agricultural non-point source pollution is one of the major causes of water quality deterioration. Based on the analysis of the spatial discharge characteristics and intensity of major pollutants from the agricultural pollution source, the establishment of spatial management subzones for controlling agricultural non-point pollution and a design of a plan for total load control of pollutants from each subzone is an important way to improve the efficiency of control measures. In this paper the Four Lake basin in Hubei Province is adopted as the research case region and a systematic research of the control countermeasures of agricultural non-point pollution based on the catchment scale is carried out. The results shows that in the Four Lake basin, the COD, total nitrogen, total phosphorus and ammonia nitrogen load of the water environment are mainly caused by agricultural non-point pollution. These four kinds of non-point source pollutants respectively account for 67.6%, 82.2%, 84.7% and 50.9% of the total pollutant discharge amount in the basin. The analysis of the spatial discharge characteristics of non-point source pollutants in the Four Lake basin shows that the major contributor source regions of non-point source pollutant in the basin are the four counties, including Honghu, Jianli, Qianjiang and Shayang where the aquatic and livestock production are relatively developed. According to the spatial discharge characteristics of the pollutants and the evaluation of the discharge intensity of pollutants, the Four Lake basin is divided into three agricultural non-point pollution management subzones, which including Changhu upstream aquatic and livestock production pollution control subzone, Four-lake trunk canal rural non-point source pollution control subzone and Honghu aquatic production pollution control subzone. Specific pollution control measures are put forward for each subzone. With a comprehensive consideration of the water quality amelioration and the allowable discharge of pollutants, a total load control solution is designed for the three non-point pollution management subzones, so as to fulfill the requirements of all indices of the monitoring sites and the requirements for the allowable discharge of pollutants of the water. Among the major pollutants, the major COD reduction area includes the Four-lake trunk canal subzone and the Honghu Lake subzone, which respectively account for 43% and 42% of the total COD reduction amount; the major ammonia nitrogen reduction area includes the Four-lake trunk canal subzone, accounting for 66% of the total ammonia nitrogen reduction amount; the major total nitrogen reduction area covers the Four-lake trunk canal subzone and the Honghu Lake subzone, accounting for 42% and 31% of the total nitrogen reduction amount in the basin respectively; the major total phosphorus reduction area is the Four-lake trunk canal subzone, accounting for 53% of the total phosphorus reduction amount in the basin.

[Spectroscopy study of methyl parathion molecularly imprinted polymers].

Three molecularly imprinted polymers were synthesized with different functional monomers respectively, using methyl parathion as the template. These monomers are methacrylic acid, acrylamide and 4-vinylpyridine. According to the UV spectrum study the interaction between methyl parathion and 4-vinylpyridine was stronger than that of the others. Comparably, the infrared spectrum study showed the same results which indicated that 4-vinylpyridine could associate with the template at two different kinds of binding sites, the P-O-C and the -NO2 site, and is most likely to form steady covalent bonds with methyl parathion, while the other two monomers could only associate with the template at the P-O-C site. Furthermore, the infrared spectra of the synthesized polymers confirmed the existence of the functional groups in each kind of polymer, which might interact with the template.

Defluoridation of water using neodymium-modified chitosan.

The water containing high fluoride ions could do harm to human and environment. In this work, the applicability of neodymium-modified chitosan as adsorbents for the removal of excess fluoride ions from water was studied. The effect of various physico-chemical parameters such as temperature (283-323 K), pH (5-9), adsorbent dose (0.2-2.0 g L(-1)), particle size (0.10-0.50mm) and the presence of co-anions (NO(3)(-), Cl(-) and SO(4)(2-)) on removal of fluoride ions were studied. The equilibrium sorption data were fitted reasonably well for Langmuir isotherm model, the maximum equilibrium sorption had found to be 11.411-22.380 mg g(-1). Sorption dynamics study revealed that the pseudo-second-order was suitable to describe the kinetics process of fluoride ions sorption onto the adsorbent with the initial sorption rate 1.70, 2.10 and 2.67 mg g(-1)min(-1) at 283, 303 and 323 K, and the sorption process was complex, both the boundary of liquid film and intra-particle diffusion contributed to the rate-determining step. The used adsorbents could be regenerated in 24h by 4 g L(-1) of sodium hydroxide.