Spatial changes and driving factors of lake water quality in Inner Mongolia, China

Lakes play important roles in sustaining the ecosystem and economic development in Inner Mongolia Autonomous Region of China,but the spatial patterns and driving mechanisms of water quality in lakes so far remain unclear.This study aimed to identify the spatial changes in water quality and the driving factors of seven lakes(Juyanhai Lake,Ulansuhai Lake,Hongjiannao Lake,Daihai Lake,Chagannaoer Lake,Hulun Lake,and Wulannuoer Lake)across the longitudinal axis(from the west to the east)of Inner Mongolia.Large-scale research was conducted using the comprehensive trophic level index(TLI(Σ)),multivariate statistics,and spatial analysis methods.The results showed that most lakes in Inner Mongolia were weakly alkaline.Total dissolved solids and salinity of lake water showed obvious zonation characteristics.Nitrogen and phosphorus were identified as the main pollutants in lakes,with high average concentrations of total nitrogen and total phosphorus being of 4.05 and 0.21 mg/L,respectively.The values of TLI(Σ)ranged from 49.14 to 71.77,indicating varying degrees of lake eutrophication,and phosphorus was the main driver of lake eutrophication.The lakes of Inner Mongolia could be categorized into lakes to the west of Daihai Lake and lakes to the east of Daihai Lake in terms of salinity and TLI(Σ).The salinity levels of lakes to the west of Daihai Lake exceeded those of lakes to the east of Daihai Lake,whereas the opposite trend was observed for lake trophic level.The intensity and mode of anthropogenic activities were the driving factors of the spatial patterns of lake water quality.It is recommended to control the impact of anthropogenic activities on the water quality of lakes in Inner Mongolia to improve lake ecological environment.These findings provide a more thorough understanding of the driving mechanism of the spatial patterns of water quality in lakes of Inner Mongolia,which can be used to develop strategies for lake ecosystem protection and water resources management in this region.

The effect of Some Boron Derivatives on Kanamycin Resistance and Survival of E.coli and P.aeruginosa in Lake Water

Objective To study MIC value of 7 boron derivatives namely [Boric acid （H3BO3）, Anhydrous Borax （Na2B407）, Sodium Borate （NaBO2）, Diammonium Tetraborate （NH4）2B4O7, Sodium Perborate （NaBO3）, Boron Trioxide （B203）, Potassium Tetraborate （K2B407）] on E. coil and P. aeruginosa and their effects on survival of bacteria in lake water and resistance against kanamycin antibiotic. Methods MIC values of Boron derivatives and antibiotic were studied by broth microdilution method. The effect of boron derivatives on survival of bacteria in lake water were also determined with plate count. Results Sodium perborate was determined as the substances. Effectiveness increased as temperature most effective substance among the studied increased. E. coil was more affected from P. aeruginosa in 8 mg/mL sodium perborate concentration in lake water. Moreover, it was determined that MIC value of kanamycin antibiotic decreased 200 times by especially treating P. aeruginosa with sodium perborate in lake water. However, it can be stated that this change in resistance did not arise from microorganisms. Conclusion Sodium perborate solution can be used supportedly in kanamycin antibiotic applications for P. aeruginosa. Future studies are necessary to explore the relation between sodium perborate and kanamycin which is effective on P. aeruginosa in lake water.

Ensuring water security by utilizing roof-harvested rainwater and lake water treated with a low-cost integrated adsorption-filtration system

Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.

Quality Evaluation of Lake Water and Sediment Based on Multilevel Fuzzy Theory

[ Objective ] The study aimed to assess the pollution of water and sediment in Wuliangsuhai Lake based on multilevel fuzzy theory. [ Method] On the basis of measured and survey data, the quality of water and sediment in six representative sites of Wuliangsuhai Lake was evalu- ated by using multilevel fuzzy theory. [ Result] Water quality of Wuliangsuhai Lake was different in space, that is, the water quality closer to outfalls was poor, but the water quality became better from north to south with the direction of water flow. Sediment near the water exit was at Grade IV, while it was at GradeV in other sites. From the evaluation results of water and sediment, we could see that Wuliangsuhai Lake was suffering serious pollution, and eutrophication process was aggravating, so it is extremely urgent to control and restore Wuliangsuhai Lake. [Conclusion] The re- search could provide scientific references for controlling the pollution of Wuliangsuhai Lake.

Lake Water Monitoring Data Assessment by Multivariate Statistics

The application of multivariate statistical methods to high mountain lakes monitoring data has offered some important conclusions about the importance of environmetric approaches in lake water quality assessment. Various methods like cluster analysis and principal components analysis were used for classification and projection of the data set from a big number of lakes from Pirin Mountain in Bulgaria. Additionally, self-organizing maps of Kohonen were constructed in order to solve some classification tasks. An effort was made to relate the maps with the input data in order to detect classification patterns in the data set. Thus, dis-crimination chemical parameters for each pattern (cluster) identified was found, which enables better inter-pretation of the ecological state of the system. A methodology for application of combination of different environmetric methods was suggested as a pathway to interpret high mountain lake waters monitoring data.

Morphological Characteristics of Cambodia Mekong Delta and Tonle Sap Lake and Its Response to River-Lake Water Exchange Pattern

Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversity. The river-lake relationship between Mekong River and Tonle Sap Lake is unique and has always been a major focus in the international community. The land terrain and under-water topography were used to analyze the morphological characteristics of Cambodia Mekong Delta and Tonle Sap Lake. Long series of hydrological data of river-lake controlling stations were used to analyze the water level variation characteristics and water volume exchange pattern between Mekong River and Tonle Sap Lake, and the response relationship to river-lake morphological characteristics were also researched. The results show that: Cambodia Mekong Delta and Tonle Sap Lake Area is low-lying and flat with gentle channel gradient and water surface gradient, making the relationship between water level and area (or volume) smooth. The channel storage capacity of Mekong River and Tonle Sap River is not enough compared to the inflow, so vast flooding plain is extremely prone to be inundated, making the flood relationships between the left and right banks become very complicated. Tonle Sap Lake is a seasonal freshwater lake with water flowing in and flowing out, and the timing and intensity of water exchange with Mekong River are closely related to the water flow resistance at the exit section of Tonle Sap Lake and the cross-sectional area of Tonle Sap River, which can be reflected by the river-lake water level difference and the water level of Tonle Sap River. Affected by the river-lake morphological characteristics, the water exchange intensity between Mekong River and Tonle Sap Lake is great. Tonle Sap Lake not only stores 14.4% of flood volume (39.7 billion m3) from the Mekong River every year, but also supplies 29.7% of dry water (69.4 billion m3) to the Mekong River. Influenced by the adjustment of the floodplain, the water level fluctuation of Mekong River and Tonle Sap Lake is slow, and the rising and droop rates of water level are positively correlated with the floodplain storage area. The research results will help to understand the relationship mechanism between Mekong River and Tonle Sap Lake and provide a scientific basis for the comprehensive governance of Cambodia Mekong Delta and Tonle Sap Lake Area.

Geochemical Characteristic and Fluxes of Trace Metals in the Poyang Lake Water System

The heavy metal pollution caused by human activities in river system has become a topic of great concern to multidisciplinary research.Recently,as the economic booming and industrial development,more and more waste is charging into the river and lake in different ways,which would induce serious environmental problem.In this research,the Poyang Lake was selected as the research area,the content,

The Construction and Study of Nansi Lake Water Environment Management Platform Based on WebGIS

According to targets and needs of Nansi Lake water eco-environment management, we took the advantages that WebGIS serves as an overall solution, combined characteristic of SuperMap IS.net WebGIS service platform and adopted the B/S three-tier distributed architecture to put forward the overall design idea, function structure and structure scheme of Nansihu water eco-environment assessment and management WebGIS. Subsequently, we used the C# programming language to carry out the concrete development job, and figured out a scheme to store and disseminate space data and attributes data. Ultimately, with the aid of SuperMap’s large-scale spatial database engine SDX+, the system has realized a lot of functions such as spatial information search, hydrology and water quality information inquiry and statistics, water environment quality assessment, lake eutrophication assessment, embodying the visualization of systems analysis sufficiently. The system has been mainly studied and developed in the technology of lake eco-environment management, and also provided an intuitionistic, universal, convenient and reliable management tool for Nansihu water eco-environment management.

Pit Lake Water Quality of Central India

Several pit lakes exist in the Raipur area due to lime stone mining. The water of pit lakes is used for bathing, washing and irrigation purposes. They are found to be contaminated with toxicants i.e. fluoride, surfactants and microbes far above the recommended limits. In this work, the water quality of 29 pit lakes locates in two districts: Raipur and Baloda Bazar, Chhattisgarh, India are assessed for drinking and irrigation purposes.

Impact of land use change on water quality in the Dianchi Lake watershed, Yunnan, China, 1988-2008

Land use changes occurring in China during the time period of rapid economic development are linked to the degradation of water quality in streams and lakes. This paper examines these linkages in the Dianchi Lake watershed in Yunnan in southwest China based on a twenty-year data set from 1988 to 2008. Pearson correlation analysis and simple linear regression analysis are employed to explore the relationships between land use change and water quality of two sub-basins, the Caohai Lake basin and the Waihai Lake basin, within the Dianchi Lake watershed. Land use categories more strongly correlate to water quality in the Caohai Lake basin than that in the Waihai Lake basin. The different structure of land use categories, spatial distribution of land cover, and scales of buffer zones could be the factors resulting in the dissimilarities between these two lakes. The research can provide valuable insights for policymakers into land use management in order to curb further water degradation in Dianchi Lake.

Evaluation of the Bacteriological Pollution of the Waters of the Lake of Sonfonia Commune of Ratoma (Republic of Guinea) 2021

The quality of surface waters is often altered by the presence of bacteria of faecal origin, as a result of untimely discharge of solid and liquid waste from households. The Sonfonia Lake located in the commune of Ratoma is under the influence of various forms of pollution resulting for the most part from anthropic activities. Field visits, interviews with resource persons and bacteriological analysis were carried out to assess the level of this pollution. Two water sampling campaigns were carried out during the low-water period and two others during the flood period of 2021. The comparison of the levels of faecal contamination bacteria in the present study with a previous one carried out in 2018 on the waters of the same lake, indicates an increase in the level of faecal coliforms and faecal streptococci that exceed the indicator values recommended by the WHO. These results show that Lake Sonfonia is polluted. This could be related to the increase in anthropogenic and demographic activities during the last four years. On the other hand, the analysis of the results showed the absence of pathogenic germs such as salmonella. The Mann-Whitney U statistical test was used to compare the value of the means of each of the variables observed during the two seasons.

Distribution of 26 Metals in the Waters of the Aquatic Ecosystems of the Cotonou Channel and Lake Nokoué, Benin

Metallic elements have various origins: natural and anthropogenic sources as geochemical, marine and atmospheric sources resulting from the fallout of pollutants emitted or dust raised and which are transported by water and air currents. Thus marine, brackish and fresh continental waters may have high metal concentrations. In addition, some essential metals can become toxic above certain concentration values in aquatic environments. The aquatic ecosystems of Cotonou channel and lake Nokoué receive the pollutants charges from the town cities of Cotonou, Abomey-Calavi and town hall of So Ava. The aim of this study is to analyze waters from Eighteen (18) stations identified in the two ecosystems (nine by ecosystem). The concentrations of magnesium (Mg), calcium (Ca), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), beryllium (Be), aluminum (Al), strontium (Sr), molybdenum (Mo), silver (Ag), tin (Sn), barium (Ba), platinum (Pt), mercury (Hg), thallium (Tl), lead (Pb), thorium (Th) and uranium (U) were measured after acid digestion of the water samples using the inductively coupled plasma source mass spectrometer (ICP-MS). The results of the analyses indicate an unequal distribution of metals in the different ecosystems. However, atypical concentrations were observed at some stations of the lake and the channel. Magnesium, calcium and manganese have very high values in Lake Nokoué respectively at Ganvié market station GAN_M (2990 ± 105 mg/L), Ganvié center, station GAN_C (4991 ± 177 mg/L) and Lake middle station MLak4 (10662 ± 17.03 μg/L). On the other hand, iron, aluminum and strontium have very high concentrations in the Cotonou Channel respectively at Agbato station AGB (5236 ± 103 and 8289 ± 519 μg/L) and at the estuary station EST (6118 ± 68 μg/L). The concentrations were compared to wells and cborehole waters in sixth neighborhood of Cotonou. We have used statistical analyzers such as MANOVA which have made it possible to classify the waters and metals in the ecosystems studied compared to groundwater and Well water waters. We use hierarchical clustering on principal components to identify similarities between stations based on metal concentration with R software packages “FactoMineR” and “factoextra”. In general, we can conclude that most of the metals have an anthropogenic source except strontium and major elements (Ca and Mg) which could respectively provide from marine waters and geochemical sources.

Investigation of Adsorption Rates of Pb, Cd, Cu, Co and Ni to Fresh-water Surface Coatings Developed in Nanhu Lake

The adsorption kinetics of five heavy metals onto the natural surface coatings, which were collected in the Nanhu Lake in Changchun, Jilin Province, China, were investigated for the purpose of giving some explanations for the mechanisms of heavy metal adsorption onto the surface coatings with initial metal ions of 5 μmol/L. The results show that firstly, the adsorption of heavy metals onto the surface coatings follows the first order kinetics; secondly, the double-constant rate equation is suitable to describing the adsorption of heavy metals selected onto the natural aquatic surface coatings, following the order K_ Cu>K_ Pb>K_ Co>K_ Ni>K_ Cd; thirdly, there is a significant correlation between the adsorption rate and the physical and chemical characteristics of heavy metals, such as E 0, Δ_fH 0_m, and Δ_fG 0_m based on the linear regression analysis.

Cholera outbreak caused by drinking lake water contaminated with human faeces in Kaiso Village,Hoima District,Western Uganda,October 2015

Background:On 12 October 2015,a cholera outbreak involving 65 cases and two deaths was reported in a fishing village in Hoima District,Western Uganda.Despite initial response by the local health department,the outbreak persisted.We conducted an investigation to identify the source and mode of transmission,and recommend evidenceled interventions to control and prevent cholera outbreaks in this area.Methods:We defined a suspected case as the onset of acute watery diarrhoea from 1 October to 2 November 2015 in a resident of Kaiso Village.A confirmed case was a suspected case who had Vibrio cholerae isolated from stool.We found cases by record review and active community case finding.We performed descriptive epidemiologic analysis for hypothesis generation.In an unmatched case-control study,we compared exposure histories of 61 cases and 126 controls randomly selected among asymptomatic village residents.We also conducted an environmental assessment and obtained meteorological data from a weather station.Results:We identified 122 suspected cases,of which six were culture-confirmed,47 were confirmed positive with a rapid diagnostic test and two died.The two deceased cases had onset of the disease on 2 October and 10 October,respectively.Heavy rainfall occurred on 7-11 October;a point-source outbreak occurred on 12-15 October,followed by continuous community transmission for two weeks.Village residents usually collected drinking water from three lakeshore points-A,B and C:9.8%(6/61)of case-persons and 31%(39/126)of control-persons were found to usually use point A,21%(13/61)of case-persons and 37%(46/126)of control-persons were found to usually use point B(OR=1.8,95%CI:0.64-5.3),and 69%(42/61)of case-persons and 33%(41/126)of control-persons were found to usually use point C(OR=6.7;95%CI:2.5-17)for water collection.All case-persons(61/61)and 93%(117/126)of control-persons reportedly never treated/boiled drinking water(OR=∞,95%CIFisher:1.0-∞).The village’s piped water system had been vandalised and open defecation was common due to a lack of latrines.The lake water was found to be contiminated due to a gully channel that washed the faeces into the lake at point C.Conclusions:This outbreak was likely caused by drinking lake water contaminated by faeces from a gully channel.We recommend treatment of drinking water,fixing the vandalised piped-water system and constructing latrines.

Quantitative reconstruction of the lake water paleotemperature of Daihai Lake, Inner Mongolia,China and its significance in paleoclimate

By measuring Sr/Ca ratios of the ostracod shells (Limnocythere cf. inopinata) in sediments of the Daihai Lake, and combined with Sr2+/Ca2+ ratios of the lake water, this paper obtained paleosalinity of the lake water. Vaporizing experiment of the lake water in laboratory showed that there was a quantitative relationship between salinity and oxygen isotope. Using this relationship, oxygen isotope values of the paleo-lake water were calculated. By measuring the oxygen isotope of the authigenic carbonate in the lake's sediments, and in combination with the oxygen isotope values of the paleo-lake water, the paleotemperature of the lake water was calculated. Finally, based on these proxies, the paleoclimate in the lake basin was explored.

Relationship Between Changes of River-lake Networks and Water Levels in Typical Regions of Taihu Lake Basin,China

The typical regions of the Taihu Lake Basin,China,were selected to analyze the variation characteristics of river-lake networks under intensive human activities.The characteristics of the fractal dimension of river networks and lakes for different periods were investigated and the influences of river system evolution on water level changes were further explored through the comparison of their fractal characters.The results are as follows:1) River network development of the study area is becoming more monotonous and more simple;the number of lakes is reducing significantly,and the water surface ratio has dropped significantly since the 1980s.2) The box dimension of the river networks in all the cities of the study area decreased slowly from the 1960s to the 1980s,while the decrease was significant from the 1980s to the 2000s.The variations of lake correlation dimension are similar to those of the river network box dimensions.This is unfavorable for the storage capacity of the river networks and lakes.3) The Hurst exponents of water levels were all between 0.5 and 1.0 from the 1960s to the 1980s,while decreased in the 2000s,indicating the decline in persistence and increase in the complexity of water level series.The paper draws a conclusion that the relationship between the fractal dimension of river-lake networks and the Hurst exponents of the water level series can reveal the impacts of river system changes on flood disasters to some extent:the disappearance of river networks and lakes will increase the possibility of flood occurrence.

Phosphorus in Interstitial Water Induced by Redox Potential in Sediment of Dianchi Lake,China

The sediment redox potential was raised in the laboratory to estimate reduction of internal available phosphorus loads,such as soluble reactive phosphorus(SRP)and total phosphorus(TP),as well as the main elements of sediment extracts in Dianchi Lake.Several strongly reducing substances in sediments,which mainly originated from anaerobic decomposition of primary producer residues,were responsible for the lower redox potential.In a range of -400 to 200 mV raising the redox potential of sediments decreased TP and SRP in interstitial water.Redox potentials exceeding 320 mV caused increases in TP,whereas SRP maintained a relatively constant minimum level.The concentrations of Al,Fe, Ca^(2+),Mg^(2+),K^+,Na^+ and S in interstitial water were also related to the redox potential of sediments,suggesting that the mechanism for redox potential to regulate the concentration of phosphorus in interstitial water was complex.

Variation Characteristics of Water Environmental Capacity in Poyang Lake under the Scheduling of Three Gorges Reservoir

[Objective] The aim was to study the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir.[Method] Choosing chemical oxygen demand (COD),total nitrogen (TN) and total phosphorus (TP) as the control indexes of pollutants in Poyang Lake,the variation characteristics of water environmental capacity in Poyang Lake under the scheduling of Three Gorges Reservoir were analyzed based on the water environment mathematical models of organic compounds and nutrients.[Result] After the operation of Three Gorges Project,high water level in Poyang Lake lasted for a long time in flood season when Three Gorges Reservoir increased discharge volume,while water level went down obviously with the accelerating of recession flow when reservoir decreased discharge volume to store water,so Three Gorges Project had obvious effects on the hydrological regime of Poyang Lake.In 2009,when Three Gorges Reservoir stored water,the water environmental capacity of COD,TN and TP in Poyang Lake in October decreased by 14.0%,15.4% and 15.4% compared with those before operation,while they increased by 3.64%,4.88% and 4.88% in August when reservoir discharged water to prevent flood.[Conclusion] The study could provide scientific foundation for the water pollution control and water environment management of lakes.

Groundwater contributions in water-salt balances of the lakes in the Badain Jaran Desert,China

Groundwater-fed lakes are essential for the ecology in arid and semiarid regions.As a typical arid region,the Badain Jaran Desert （BJD） is famous in the world for the presence of a large number of groundwater-fed saline lakes among the mega dunes.Based on the up to date geological surveys and observations,this study analyzed the groundwater contributions in water-salt balances of the lakes in the desert.We found different types of springs,including the sublacustrine springs that indicate an upward flow of groundwater under the lakebed.A simplified water balance model was developed to analyze the seasonal variations of water level in the Sumu Barun Jaran Lake,which revealed an approximately steady groundwater discharge in the lake and explained why the amplitude of seasonal changes in lake level is less than 0.5 m.In addition,a salt balance model was developed to evaluate the salt accumulations in the groundwater-fed lakes.The relative salt accumulation time is 800–7,000 years in typical saline lakes,which were estimated from the concentration of Cl-,indicating a long history evolution for the lakes in the BJD.Further researches are recommended to provide comprehensive investigations on the interactions between the lakes and groundwater in the BJD.

Study on the Water Quality and Protection Measures of Dongting Lake

From nitrogen and phosphorus,chemical oxygen demand,phytoplankton,and eutrophication,this article analyzes the current situation of water quality in the Dongting Lake area,and discusses the factors influencing the water quality of Dongting Lake. Based on the actual production,geographic characteristics and outstanding problem of grim water pollution situation in the Dongting Lake area,some specific proposed measures are put forward in order to provide the basis and reference for the future pollution control in the Dongting Lake area,such as strengthening the industrial pollution control,developing ecological agriculture,and enhancing ecological restoration and water quality early warning.