Relationships Between River Water Quality and Landscape Factors in Haihe River Basin, China: Implications for Environmental Management

River water plays a key role in human health, and in social and economic development, and is often affected by both natural factors and human activities. An in-depth understanding of the role of these factors can help in developing an effective catchment management strategy to protect precious water resources. This study analyzed river water quality, patterns of terrestrial and riparian ecosystems, intensity of agricultural activities, industrial structure, and spatial distribution of pollutant emissions in the Haihe River Basin in China for the year of 2010, identifying the variables that have the greatest impact on river water quality. The area percentage of farmland in study area, the percentage of natural vegetation cover in the 1000-m riparian zone, rural population density, industrial Gross Domestic Product(GDP)/km^2, and industrial amino nitrogen emissions were all significantly correlated with river water quality(P < 0.05). Farming had the largest impact on river water quality, explaining 43.0% of the water quality variance, followed by the coverage of natural vegetation in the 1000-m riparian zone, which explained 36.2% of the water quality variance. Industrial amino nitrogen emissions intensity and rural population density explained 31.6% and 31.4% of the water quality variance, respectively, while industrial GDP/km^2 explained 26.6%. Together, these five indicators explained 67.3% of the total variance in water quality. Consequently, water environmental management of the Haihe River Basin should focus on adjusting agricultural activities, conserving riparian vegetation, and reducing industrial pollutant emissions by optimizing industrial structure. The results demonstrate how human activities drive the spatial pattern changes of river water quality, and they can provide reference for developing land use guidelines and for prioritizing management practices to maintain stream water quality in a large river basin.

Anthropogenic disturbance of aquatic biodiversity and water quality of an urban river in Penang, Malaysia

Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water. Healthy aquatic ecosystems are supported by physicochemical properties and biological diversity. This study evaluated the anthropogenic impacts on aquatic biodiversity, especially plankton, fish, and macrobenthos, as well as the water quality of the Juru River in the Penang area. Aquatic biodiversity and river water parameters were collected from ten sampling stations along the Juru River. Seven variables were used to assess the physicochemical environment: pH, temperature, total suspended solids (TSS), salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand. At each sampling station, the total number of plankton, fish, and macrobenthic taxa were counted and analyzed. The relationships between the physicochemical parameters and aquatic biodiversity were investigated with biotypological analysis, principal component analysis, hierarchical cluster analysis, and linear regression analysis. These analyses showed that the richness and diversity indices were generally influenced by salinity, temperature, TSS, BOD, and pH. The data obtained in this study supported the bioindicator concept. The findings, as they related to scientifically informed conservation, could serve as a model for Juru River management, as well as for river management throughout Malaysia and other tropical Asian countries.

Optimization of sampling frequency for routine river water quality monitoring

Sampling frequency is an important factor to be considered during the design of a water monitoring network,and the cost-effective selection of possible ways and means for the optimization of sampling frequency is still needed.This paper introduces water pollution index deviation ratio comparison(WPI DRC),a procedure for the optimization of sampling frequency for a routine river water quality monitoring system.Sampling frequency optimized using WPI DRC at monitoring station X5 in the mainstream of Xiangjiang River is compared with that established using the traditional Statistical Algorithm method.The result of comparison indicates that WPI DRC is more feasible than the traditional one.And then,the sampling frequencies for other 16 monitoring stations also have been optimized,and the results show the sampling frequencies of all the stations except that X4 are reduced,and there is no unacceptable difference between water quality evaluation results at 17 stations before and after the optimization.Therefore,it is concluded that WPI DRC is an effective optimization process with operable results,which can be used to fulfill the requirement of practical monitoring work.

Land use change in highland area and its impact on river water quality:a review of case studies in Malaysia

The policy of encouraging agriculture and development for mass tourism has led to environmental problems in Cameron Highlands,Malaysia.Rampant development and land clearing have significantly altered the land cover of Cameron Highlands for the past 30 years.Sensitive highlands areas are prone to landslides and soil erosion which then contributed to the main water pollution issues in the network of river system,sedimentation and siltation.The continuous trend of river water quality deterioration in Cameron Highlands has raised the issues for discussion in this review article.The purpose of this review is to briefly summarize the land use change,agriculture practices,agro-tourism,and agriculture policy and management toward water quality of the river system network in Cameron Highlands specifically in the downtown where most of the development and agriculture activities are concentrated.A rigorous review has been done on the existing literature to determine the relationship between land use change and agriculture practices toward river water quality in Cameron Highlands from 2001 to 2017.The total number of reviewed papers was 68.The outcomes established from previous researchers have highlighted factors such as soil erosion,landslides,agriculture activities,urbanization,and unplanned development associated with land use change have significantly influenced the river water quality in the highland areas.Continuous land use changes without proper development plan and law enforcement may critically threaten the sustainability of river network in the highlands area.

Spatial variations of river water quality in Pearl River Delta, China

In Pearl River Delta （PRD）, river water quality has deteriorated gradually due to population increase and ongoing industrialization and urbanization. In this study, multivariate statistic methods were used to assess water quality spatial pattern and to identify characteristics of water quality variation in the PRD. Water quality monitoring of the PRD during the year 2005 and 2008 was conducted at 25 different stations. Seventeen water quality parameters were analyzed for further studying. Results of one-way analysis of variance （ANOVA） indicated that all the parameters except air temperature, water temperature and zinc showed significant difference among monitoring stations in both dry and wet season. Monitoring stations in the PRD were separately classified into three statistically significant clusters at （Olink/Omax） （ 2 in dry and wet season, respectively. The three clusters indicated the similarity and dissimilarity of river water quality among 25 monitoring stations, corresponding to heavy pollution, moderate pollution and slight pollution. Thus, the results of this study are useful to evaluate water quality and manage water resources in the PRD.

Distribution of Selected Toxic Elements in Water Phases of River Ogbere, Ibadan, Nigeria

Rivers in Nigeria are faced with increasing contamination of both solid and liquid wastes that enter the surrounding water bodies, and some of these are toxic pollutants that settle onto the riverbed (the ultimate sink of contaminants in the aquatic environment). These toxic pollutants are released into the aquatic environments and inadvertently pose serious public health risks and hazards. This study aims to assess the level of potentially toxic element in River Ogbere water in the city of Ibadan. A total of 12 surface water samples collected from River Ogbere in Ibadan during the dry and wet season of 2019 was analysed for pH, EC, Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Cadmium (Cd), Chromium (Cr), Lead (Pb) and Nickel (Ni). The pH was found in the alkaline range (7.40 - 7.83) while the conductance was obtained in the range of 236.67 - 353.3 μs/cm in both seasons. Fe, Mn, Zn, Cu, Cr, Pb, and Ni were detected in all the samples in the range 0.10 - 5.44 mg/L, 3.20 - 5.03 mg/L, 0.12 - 1.27 mg/L, 0.03 - 0.51 mg/L, 0.03 - 0.68 mg/L, 0.01 - 0.75 mg/L and 0.01 - 0.03 mg/L in both seasons respectively, whereas Cd was detected only in 75% of the samples (0.00 - 0.07 mg/L). Overall seasonal variation was significant for Fe, Mn, Pb, Cd, and Cr. The maximum mean concentration of Fe (5.44 mg/L), Mn (5.03 mg/L), Zn (1.27 mg/L), Cu (0.68 mg/L), Pb (0.75 mg/L) and Ni (0.03 mg/L) were all observed during the dry season. The heavy metals also varied with the change of sampling locations. The dominance of these toxic element in the surface water of River Ogbere followed the sequence: Mn > Fe > Zn > Cu > Cr > Pb > Ni > Cd. The anthropogenic activities around the study area were observed to have increased the influx of toxic metals at both upstream and downstream sections of the river. In view of the high human activities along the river, River Ogbere appeared to have been polluted visibly. The constant water quality monitoring and development of River Ogbere safety plans is recommended.

Influence of Atmospheric Particulate Matters on Underlying Surface of Water Body

The air quality and the river water quality of the underlying surfaces in Shanghai and some areas of the Netherlands after environmental treatment were analyzed respectively, and the correlation between them was explored. A long-term family experiment was carried out to figure out the causes of water turbidity, and the correlations of turbidity and pH in water with the PM2.5 index in air quality were probed. Then, the air quality was found to be correlated, to some extent, with the river water quality of underlying surfaces, in which the PM2.5 index was strongly correlated with the river water quality.

Analysis of Pollutant Load Carrying Capacity of the River Tapi Using QUAL2Kw for Surat City

River Tapi is the prime water body for Surat city, Gujarat, India. On a long stretch of 22.39 km in Surat city (Kamrej to Causeway) of the Tapi river, there are many identified and non-identified discharge points available. Excessive discharge from these points restricts the efficiency of the self-purification process which ultimately degrades the river water quality. In this paper, an attempt has been made to estimate the pollutant load-carrying capacity at different segments of the river Tapi using the QUAL2Kw tool. The study has been undertaken with different scenarios: First, the QUAL2Kw model was trained with available river water quality and hydraulic data of the Tapi river in which the complete river segment was divided into 21 reaches. The model was calibrated and validated with the actual concentrations of the pollutants entering. In the second phase, all the point source, non-point source, and headwater characteristics were considered and the pollutant load-carrying capacity of the river in terms of BOD, ISS, and N-nitrate was found. In the third phase, all the sources of pollutants entering the river have been removed and only headwater characteristics were considered for the study. The results indicate that reach no. 21 (21.23ºN, 72.82ºE) has the maximum load-carrying capacity of Biochemical Oxygen Demand (BOD) up to 2057.7 kg/day, Inorganic Suspended Solids (ISS) up to 85633.8 kg/day, and Nitrate (NO3) up to 31688.8 kg/day. However, reach no. 4 has the minimum load carrying capacity of BOD up to 1088.1 kg/day, reach 8 carries a minimum of ISS 205341.6 kg/day and NO3 10215.57 kg/day.

Study of River Water Environment Simulation on WebGIS

Along with economic development, river pollution has become a serious phenomenon. It＇s rational to simulate variation of pollutants by using water quality model. Thus, relevant departments could take appropriate measures to improve the water environment. However, the traditional image of mathematical modeling is not intuitive. The advantage of WebGIS is the ability of visualization on web browser by the combination ofgeospatial data and pollution attribute data.

Development of integrated catchment and water quality model for urban rivers

This paper presents the development of an urban river water quality model which considers the physical-biochemical processes within rivers and the incorporated urban catchment rainfall-runoff process developed with the time-area method. Unlike other models that simulate the hydrological and receiving water quality processes in the rural areas of the watershed scale, the model developed here is typically efficient for simulating the water quality response to nonpoint loadings from urban drainage systems, where the hydrological process is disturbed by artificially pumped discharge in wet-weather periods. This model is employed to assess the river water quality restoration in Nanfei River in Hefei City, China, where the model is calibrated against the measured data（i.e., the COD, the BOD5, the NH3-N, and the DO） in 2010, and the model parameters are suggested. It is shown that the nonpoint pollutants from the urban catchments contribute 34%-47% of the total pollutant inputs（i.e., the COD, the BOD5, and the NH3-N）, despite their low flow component of 13.4%. Apart from the improvement of the wastewater treatment plant effluent（i.e., Grade IV of the Surface Water Quality Standard）, a nonpoint loading reduction of 27.2%, 25.1%, and 35.3% of the COD, the BOD5, and the NH3-N are anticipated to meet the designated surface water quality standards of Grade V.

DEVELOPMENT OF TWO-DIMENSIONAL HYDRODYNAMIC AND WATER QUALITY MODEL FOR HUANGPU RIVER

Based on numerical computation model RMA2 and RMA4 with open source code,finite element meshes representing the study domain are created, then the finite elementhydrodynamic and water quality model for Huangpu River is developed and calibrated, and thesimulation results are analyzed. This developed hydrodynamic and water quality model is used toanalyze the influence of discharged wastewater from planning Wastwater Treatment Plant (WWTP) onHuangpu River's water quality.

Characteristics of change in water quality along reclaimed water intake area of the Chaobai River in Beijing, China

To reveal the basic characteristics and controlling factors of water quality change in the project Wenyu to Chaobai reclaimed water diversion, the water quality in the study area was monitored for one year at seven monitoring sites. Inverse geochemical models of the statistical groups were developed using PHREEQC to elucidate the hydrochemistry characteristics of reclaimed water and the factors. The monitoring results indicated that nitrogen and phosphorus contents were significantly reduced along the river mainly caused by seasonal and location variation. The pH ranged from 7.44 to 9.81. Photosynthesis of algae and denitrification in anaerobic microenvironment ultimately led to a sudden pH increase after the Jian River and the Chaobai River confluence. Mg2＋ and SO^- levels dropped obviously in the summer and increased in winter seasons after intersection. Na＋ and C1- are relatively stable, and marked drop in the concentration only after the two rivers meet. And there is a decrease of Ca2＋ and HCO~ and increase in CO^- during monitoring period. As a whole, the primary ions and nutrient components, including nitrogen and phosphorus, had high levels in winter. Algae＇s photosynthesis and respiration were observed to have an impact on the river water quality; there was precipitation-dissolution of minerals and denitrification from upstream to downstream. Inverse geochemical PHREEQC modeling confirmed that there was precipitation of aragonite or calcite, and gypsum or anhydrite in summer, and dissolution in winter; as well as precipitation of dolomite in winter, and cationic exchange and denitrification along the river.

Integrated biomarkers in wild crucian carp for early warning of water quality in Hun River, North China

Metabolizing enzymes play important roles in the detoxification of various pollutants in aquatic organisms, thereby they can also be used to provide early-warning signals of environmental risks. Real-time quantitative reverse-transcription polymerase chain reaction assays were developed to quantify cytochrome P450 1A （CYP1A）, superoxide dismutase （SOD）, glutathione peroxidase （GPx）, catalase （CAT）, and glutathione-S-transferase （GST） in crucian carp （Carassius auratus）. The methods were then used to detect the respective mRNA expression levels in liver tissue in wild crucian carp from the Hun River, North China. CYP1A mRNA expression was significantly up-regulated in fish from stations $5, $6, and $8 （p 〈 0.05）. SOD mRNA expression was significantly down-regulated in downstream areas relative to fish from upstream sites （p 〈 0.05）; GPx and CAT mRNA expression levels were also down-regulated at $9 （p 〈 0.05）. In contrast, GST mRNA expression showed no obvious change between fish collected from up- or downstream areas of the river. Finally, an integrated biomarker response was used to evaluate the integrated impact of pollutants in the Hun River and allow better comprehension of the real toxicological risk of these investigated sites.

Simulating the fate of indigenous antibiotic resistant bacteria in a mild slope wastewater polluted stream

The fate of indigenous surface-water and wastewater antibiotic resistant bacteria in a mild slope stream simulated through a hydraulic channel was investigated in outdoor experiments.The effect of（i） natural（dark） decay,（ii） sunlight,（iii） cloudy cover,（iv） adsorption to the sediment,（v） hydraulic conditions,（vi） discharge of urban wastewater treatment plant（UWTP）effluent and（vii） bacterial species（presumptive Escherichia coli and enterococci） was evaluated.Half-life time（T1/2） of E. coli under sunlight was in the range 6.48–27.7 min（initial bacterial concentration of 10^5 CFU/mL） depending on hydraulic and sunlight conditions. E. coli inactivation was quite similar in sunny and cloudy day experiments in the early 2 hr, despite of the light intensity gradient was in the range of 15–59 W/m^2; but subsequently the inactivation rate decreased in the cloudy day experiment（T1/2= 23.0 min） compared to sunny day（T1/2= 17.4 min）. The adsorption of bacterial cells to the sediment（biofilm） increased in the first hour and then was quite stable for the remaining experimental time. Finally, when the discharge of an UWTP effluent in the stream was simulated, the proportion of indigenous antibiotic resistant E. coli and enterococci was found to increase as the exposure time increased, thus showing a higher resistance to solar inactivation compared to the respective total populations.

Spatio-temporal variation of net anthropogenic nitrogen inputs in the upper Yangtze River basin from 1990 to 2012

The net anthropogenic nitrogen input(NANI) is an important nutrient source that causes eutrophication in water bodies. Understanding the spatio-temporal variation of NANI is important for regional environment assessment and management.This paper calculated NANI in the upper Yangtze River basin(YRB), upstream of the Three Gorges Dam(TGD), from1990 to 2012, and analyzed its spatio-temporal characteristics. Over the past 23 years of the study, the average annual NANI increased from 3200 kg N km^(-2) to 4931 kg N km^(-2). The major components were fertilizer N application, atmospheric N deposition,and net food and feed N import. In the northwest high mountainous region with a sparse population, the main component was atmospheric N deposition. Fertilizer N application and net food and feed N import were concentrated in the Chengdu Plain because of the high population density and large areas of farmland. This research found that NANI increased with rapid urbanization and increasing population. The Pearson correlation results illustrated that the spatial distributions of NANI and its major components were affected by land cover/use, agricultural GDP and total population. Increasing NANI has been the major cause of the degrading stream water quality over the past 20 years and is becoming a major threat to the water quality of the TGD reservoir.