Lake Water Pollution Research Articles

Potential Pollution of Mahakam Cascade Lake Water Pollution (Semayang Lake, Melintang Lake and Jempang Lake) From Garbage and Household Waste

Mahakam Kaskade Lake (Semayang Lake, Melintang Lake and Jempang Lake) is the largest flood exposure lake in East Kalimantan. The villages in Semayang Lake, Melintang Lake and Jempang Lake are settlements that are regularly flooded every year, while for generations the people in the research area have used lake water as a source of bathing, washing and latrine (MCK) water. Sources of lake water pollution are domestic waste in the form of organic and inorganic materials from residential areas in water catchment areas and lake borders. The existence of other activities in the form of agriculture, animal husbandry, home industry and tourism will add to the waste of organic and inorganic materials that enter the lake waters, therefore it is necessary to investigate the potential for lake water pollution. This study aims to determine how big the potential for water pollution of Mahakam Kaskade Lake from garbage and household waste. The research was conducted using a survey method, namely conducting interviews and direct observations in the field. The data collected in the form of primary data and secondary data that are relevant to the research objectives. Based on the survey results, it can be seen that Jempang Lake has the potential to be polluted by household organic waste 1.4 – 2.7 tons/day, Melintang Lake has the potential to be contaminated with household organic waste 0.9 – 1.4 tons/day, while Semayang Lake has the potential to be polluted. household organic waste is around 1.7 – 2.7 tons/day, while Jempang Lake has the potential to be polluted by inorganic waste (plastic) about 1.2 tons/day, Melintang Lake has the potential to be polluted by inorganic waste (plastic) about 0, 7 Tons/Day and Semayang Lake has the potential to be polluted by inorganic waste (plastic) of around 1.2 Tons/Day. Therefore, the relevant agencies must immediately try to overcome this pollution problem so that the Mahakan Cascade Lake is not further damaged

ENVIRONMENTAL ISSUES AND ENVIRONMENTAL CONSCIOUSNESS OF THE PEOPLE RESIDING IN THE PERIPHERY OF THE LOKTAK LAKE, MANIPUR, INDIA

The present study was conducted in the periphery of the Loktak by interviewing with 300 selected respondents using purposive sampling technique to assess the environmental issues of the Loktak lake and its surrounding areas and also to assess the environmental consciousness of the people living in and around the lake. All (100%) respondents reported the natural resources of Loktak lake is declining and most of them (28.33%) felt that the decline of the natural resources of Loktak lake was found to be pollution of the lake water. In the overall percentage of major environmental issues of the areas or villages in and around the Loktak lake water pollution (37%) was highest. The study found that the highest percentage in terms of the level of environmental consciousness people had was “Average” (87.33%). Improvement of education, organizing effective awareness programmes for the conservation and sustainable management of the Loktak lake and its surrounding environment, seeking alternative means of livelihoods are suggested.

Comprehensive passive-mode performance analysis on a new multiple-mode solar still for sustainable clean water processing

The solar still is potential to augment clean water supply in the rural and low-income settlements. However, the current efficiency of the device is low. In this study, we report the fabrication and experimental performance analysis of a high-efficiency multiple-mode solar still—tagged Desal-1.5. The solar still was investigated in passive mode, relying entirely on natural insolation. Both desalination and ordinary water purification experiments were conducted on the device using seawater and moderately polluted lake water, respectively, between 09:00 and 18:00 h of Malaysia's tropic weather. The optimum freshwater yield of the prototype within the interval was 5780.5 ml/m2, while the optimum solar-to-vapor conversion efficiency, evaluated using the transient latent heat of vaporization, was 161.4%. Furthermore, for the first time on a solar still geometry, condensate loss due to condensate collection channel slope has been estimated in this study for our Desal-1.5. The loss amounted to 18.5% of the actual condensate collection. Eventually, water quality assessments of distillates from the device showed good compliance with both WHO and Malaysian drinking water standards. Thus, the recommendation of the solar still to ameliorate freshwater scarcity and support sustainable clean water provision in the rural and low-income regions is strengthened.

Assessment of water quality and apportionment of pollution sources of an urban lake using multivariate statistical analysis

The Lake Gulshan has gained special attention to restore its water quality for public health safety, congenial lake bund, and aquatic lives as the lake is a popular recreational place and neighbourhood of critical residential and diplomatic zones. Therefore, this study assessed water quality and pollution sources of Lake Gulshan, located in the city of Dhaka in Bangladesh during dry and wet seasons, using the water quality index (WQI) rating system, Principal Component Analysis (PCA), and Positive Matrix Factorization (PMF) model. Extremely low levels of dissolved oxygen (as low as 0.2 mg/L in the dry season and 0.8 mg/L in the wet season) in the lake water suggest that it is almost impossible for any living organisms to survive. Consequently, high levels of biochemical oxygen demand (BOD, a measure of biodegradable organic matter up to 80 mg/L), Phosphate, and Nitrate (indicators of eutrophication potential as far as 5.06 mg-P/L and 228 mg-N/L) were detected in the lake water, indicating severe anthropogenic pollution. A strong correlation (Pearson with 2-tailed t -test, r = 0.85 in the dry season, r = 0.76 in the wet season, p < 0.05) between color and chemical oxygen demand (COD) demonstrates the pollution of lake water due to mixing effluent resulted from surrounding garments and dying industries. The WQI rating systems proposed by the National sanitation foundation (NSF) and the Canadian Council of Ministers of the Environment (CCME) show that the lake's water quality is in poor or bad condition and has become a growing concern for a looming ecological severe danger. Both PCA and PMF models have apportioned four factors as pollution sources in the lake water during dry and wet seasons. PCA's four factors explain 86.41% and 80.97% variances of the dataset during dry and wet seasons, respectively. PMF receptor model estimates that the point source of nutrients contributes to 42.94% of the total pollution generated by municipal wastewater discharge during the dry season. Hence, municipal waste discharges through the point sources are the leading causes of lake water pollution in the dry season. However, a non-point source of surface runoff shares 41.80% of the total pollution in the wet season generated by soil leaching runoff. This study could help the concerned authorities for the policymaking with strict regulations to protect water quality, proper management, and control pollution of the lake water.

Physicochemical and microbial pollution of a reservoir in South India and role of bacteriophage treatment to curtail drug-resistant bacterial pollution in water

This study aimed to assess the physicochemical and microbiological pollution of water samples collected from Bellandur Lake, Bengaluru, South India, and to study the potential of bacteriophage treatment to curtail drug-resistant bacterial pathogens. The water samples were collected from the lake during four time periods in 2018–19. The physicochemical, heavy metal, and bacteriological analyzes were studied by standard protocol. The antibiotic sensitivity profiles of the major isolates from the water samples were assessed by disk diffusion assay, and two isolates that showed resistance to the highest percentage of the tested antibiotics were characterized by 16S rRNA gene sequencing. The lake water samples were treated with the isolated bacteriophages with controls, and the reduction of viable bacterial count in the treated water samples was estimated. This study revealed that the physicochemical, heavy metal and microbiological qualities of water samples were exceeded the permissible limits set by the standard authorities ( p ≤ 0.05). When tested against 44 antibiotics, most of the isolates were found to be multidrug-resistant in which IS1 and IS2 showed resistance to the highest percentage of antibiotics, which were confirmed to be Pseudomonas aeruginosa strain DSCEbt-Bellandur01 and Pseudomonas sp. strain DSCEbt-Bellandur022, respectively. When the lake water samples were treated with the isolated bacteriophages, the study showed a 99.99 % reduction in the viable bacterial count (CFUL/ml) when compared to untreated water samples ( p ≤ 0.05). Thus, the present study suggests that bacteriophage-based therapy is one of the promising approaches to treat various water bodies to reduce microbial pollution, and the approach can be used to curtail the emergence of multi-drug resistant pathogens in the water samples. • Assessing the physicochemical and microbial pollution of lake water in South India. • Bacteriophage therapy as a potential approach in reducing MDR pathogens in water. • Lake water quality found to be poor with heavy metal and MDR bacterial pathogens. • IS1 and IS2 belonged to Pseudomonas spp. and showed 100 % antibiotic resistance. • 99.9 % reduction of CFU/ml in the treated samples with isolated bacteriophage.

Diffuse Pollution and Ecological Risk Assessment in Ludaš Lake Special Nature Reserve and Palić Nature Park (Pannonian Basin)

Diffuse water pollution from agriculture (DWPA) is one of the major factors causing water pollution in Lakes Palić and Ludaš, the two largest shallow lakes of the Pannonian Basin in Serbia. These two lakes are protected under national and international law. On the basis of the number of strictly protected bird species, Ludaš Lake has been classified as a wetland of international importance since 1977 (Ramsar site 3YU002); in 2021, both lakes were nominated as potential Natura 2000 areas. Despite the degree of protection and ecological significance of the area, agricultural land prevails. By a process of land expropriation during 2019, the buffer zone began to expand around the lakes, which should lead to a reduction in pollution. One of the goals of buffer-zone development is to enhance and restore the ecological connectivity of the remaining forest-steppe habitats. During the expropriation process, soil was sampled to record areas with the highest pollution. This paper assesses the environmental risk caused by phosphorus, nitrogen, and the accumulation of heavy metals (Zn, Cu, Pb, Cr, Ni, Mn, Cd, and Hg). For each heavy metal, the corresponding pollution indices (Igeo, PI, EF, Eri, RI, Nemerow) and soil contamination level were calculated. Pollution indices indicate the ecological risk under the influence of heavy metals in the following order: Cd &gt; Cu &gt; Ni &gt; Zn &gt; Pb &gt; Cr &gt; Hg. Results showed that concentrations of Cd exceeded the maximal permissible concentration in all examined soil samples, and high ecological risk areas were determined. High concentrations of nitrogen, phosphorus, and potassium were detected, which could be as a result of intensive agricultural activity. Current conservation measures in this area have not provided adequate protection of the natural environment. Accordingly, existing measures must be controlled or new, more restrictive measures must be prescribed.

Spatio‐temporal heterogeneities in water quality and their potential drivers in Lake Chaohu (China) from 2001 to 2017

AbstractDamage to the water ecosystems and the deterioration of lake water resources may negatively affect the surface water resources, particularly, which of the daily drinking water supply of residents. Therefore, it is particularly important to study the spatio‐temporal heterogeneity of water quality in large lakes. We analysed the data from six sampling sites in Lake Chaohu from 2001 to 2017 and eight sampling sites of the inflow rivers in 2001, 2009 and 2017. The six sampling sites were divided into SG I and SG II through cluster analysis, and the spatio‐temporal changes of the water quality in the Lake Chaohu Basin were studied. The results indicated the following: All nutrient variables had relatively high concentrations in SG II except DO, while SG I had relatively high concentrations of only TN. Besides, the value of Chl a in each group is generally high. On the temporal scale, the changes in the water quality of the lake showed strong seasonality; the nutrient variable (TN, TP, NH4‐N and CODMn) except DO in the inflow rivers is generally higher than that of the lake; the water quality of Lake Chaohu has improved during the study period, and it has also improved to a certain extent compared with that of the late 1980s. Fortunately, parts water quality parameters of Lake Chaohu have improved faster than that of the other four largest freshwater lakes in China. This research result has a certain guiding significance for the prevention and control of large lake water pollution.

A Decision Support Tool For Water Pollution and Eutrophication Prevention In Groundwater-dependent Shallow Lakes From Periurban Areas Based On The DPSIR Framework.

The deterioration of water quality worldwide is a serious environmental problem. Water managers still need operational tools to assess water issues and to inform water planning and decision-making. The aim of this article is to propose a 3-step methodological framework for assessing water pollution problems by combining a conceptual modeling tool (DPSIR) with the development of a quantitative model (Multi-Criteria Decision Model). This contribution provides a practical and flexible evaluation tool for conducting an integrated assessment of eutrophication and agrochemicals delivered to groundwater-dependent shallow lakes. It lays out action guidelines for decision-making environmental managers within the context of intermediate cities in developing countries. Forty-one indicators were identified to characterize the D-P-S-I compartments and for the multi-criteria model conceptualization. In this work, response options analysis consisted of evaluating and choosing water management instruments via a decision support tool. Two lake watersheds located in the peri-urban of two middle-size cities, in Argentina, were chosen to illustrate this methodological approach. The ensuing results allowed establishing a ranking of areas to prioritize, identifying a criteria and sub-criteria to focus on in order to set out action guidelines to minimize water pollution and eutrophication. These action guidelines are urgently needed in emerging countries, where financial, human resources and infrastructure are limited. The scarcity of such causes important implications regarding policy solutions for environmental issues. The implemented decision support tool in both lake watersheds provided a common basis for the understanding of the ongoing water pollution problems and a quantitative ranking (i.e., decision scores) for defining specific actions (responses) for human-induced stresses on such natural systems.

Distribution Characteristics and Pollution Evaluation of Nitrogen and Organic Matter in Overlying Water and Sediment of Guyun River and Jinshan Lake in Zhenjiang City

Zhenjiang City is located in the intersection of the Yangtze River and the Beijing-Hangzhou Grand Canal, which is the most important water transportation hub in China, with abundant water resources and a dense river network. In recent years, the water quality in this region has declined with the rapid development of the economy and enhanced anthropogenic activity. Therefore, it is crucial to understand the state of water and sediment pollution in rivers and lakes of Zhenjiang City, which can provide important basic data for improving the water environment quality for this region. In total, 21 sampling sites (including 10 sites from Jinshan Lake and 11 sites from the ancient canal) in Zhenjiang City were selected, and overlying water and sediment samples were sampled in winter and summer, respectively. In addition, the physical and chemical parameters of overlying water and sediment samples were determined, respectively, and the organic index as well as organic nitrogen index were analyzed in order to evaluate the degree of sediment contamination in this region. Results showed that ① The TN concentration of overlying water changed from 1.95 mg·L-1 to 15.71 mg·L-1 in the winter and from 0.64 mg·L-1 to 12.09 mg·L-1 in the summer, with mean values of 4.01 mg·L-1 and 4.07 mg·L-1, respectively, which are higher than those of the surface water Ⅴ class standard. In addition, the ranked order of NH4+-N was as follows:winter < summer and river > lake; ② the TN content in the sediment samples ranged from 394.61 mg·kg-1 to 3288.09 mg·kg-1 and from 869.21 mg·kg-1 to 3598.04 mg·kg-1, respectively, with the mean values of 1928.58 mg·kg-1 and 2068.40 mg·kg-1. The ranked order of TN, NH4+-N, NO3--N, and Org-N was as follows:winter > summer for lake sediment samples. For river sediment samples, the ranked order of TN was winter < summer, whereas those of NH4+-N and NO3--N were winter > summer, indicating more complicated seasonal distribution for river sediment. In addition, the NO3--N content was higher in lake sediment than in river sediment, whereas that of NH4+-N was higher in river sediment than in lake sediment. The C/N ratio results indicated that the organic matter in sediments primarily resulted from endogenous pollution in this region; ③ Results of organic nitrogen index confirmed that 60% sediment samples from the lake in winter and the river in summer belong to the Ⅳ pollution level, indicating that organic nitrogen pollution existed in these samples. The results of organic index confirmed that 70% and 54.55% sediments samples belong to the Ⅱ pollution level, indicating that the sediments were not severely polluted in rivers and lakes of Zhenjiang City. The results demonstrate that sediments in rivers and lakes of Zhenjiang City are mainly polluted by nitrogen. Our findings provide important basic data for nitrogen control schemes in river water and sediment in Zhenjiang City.

Participatory research to monitor lake water pollution

Abstract A participatory research team, concerned about water quality around Lake Geneva, particularly in the Montreux Bay region where some were lifeguards, ran sampling campaigns to determine summertime levels of lake water pollution. The participants were brought together serendipitously through a course organized by academic researchers and ‘biohackers’ from the community laboratory, Hackuarium. After discussion about lifeguards’ gastrointestinal and dermatological ailments each season, the decision to pursue this participatory research project was made. In order to assess water quality, thereby testing the hypothesis that unsuspected pollution enters the lake each summer season, microbiological plating of water samples was proposed. Volunteers collected and analysed water samples over summer seasons (8 weeks in 2016, 2017 and 2020) from three sites around Montreux Bay, with tap and local river water samples as controls. Contamination of lake water was measured using standard microbiological methods, with growth media allowing quantitative assessment of abundance of several bacterial species. In particular, the focus was to quantify Escherichia coli, the classic bioindicator organism for raw sewage contamination. These open science data reveal peaks of bioindicator and other bacterial pollution in lake water samples during all sampling years. For the initial two sampling campaigns, increased microbial burdens occurred during a popular music festival, and were not simply dependent upon rainfall. In contrast, only scattered, lower level bioindicator pollution events occurred across the sampling period during the pandemic summer of 2020, when the festival was cancelled. This study confirms the power of participatory research: dedicated people on a budget can do meaningful environmental monitoring. These analyses suggest that better management, both to support water quality monitoring and for event organization, is essential, as sewage treatment facilities near many popular festivals, internationally, may need to cope with increased wastewater from visitors.

Temporal trends and source apportionment of water pollution in Honghu Lake, China.

Honghu Lake, the largest shallow lake in Jianghan Plain of China, is essential for maintaining ecosystem functioning in this region. However, water pollution and high disturbance are seriously threatening the ecological security of this lake. To explore the causes of water quality fluctuations in Honghu Lake, the water quality index method (CCME-WQI), multivariate statistical, and source apportionment techniques were adopted to characterize temporal trends in lake water quality (2004-2017), identify the main driving factors of water quality indicators, and quantify the contribution of various pollution sources. Besides, the water periods of the lake have been reclassified due to the seasonal variation of rainfall in the study area. The results of CCME-WQI showed that the water quality in Honghu Lake initially improved over 2004-2011, with better water quality in the wet period than in the dry periods, while the results over 2012-2017 were found to be opposite. Correlation analysis identified untreated industrial wastewater (UIW) as the main pollution source affecting CODMn concentrations in Honghu Lake, while untreated domestic sewage discharge (UDS) was identified as the main pollution source affecting BOD and F. coli concentrations. The main pollution sources affecting nutrient indicators were rainfall and enclosure aquaculture (EA). Principal component analysis (PCA) combined with absolute principal component score-multiple linear regression model (APCS-MLR) further appointed the source contribution of each pollution source to water quality indicators. The results showed that EA in 2012 was reduced by 81% compared with 2004, resulting in the contribution of EA to NH3-N, TP, and TN decreased by 0.2 mg L-1, 0.039 mg L-1, and 0.37 mg L-1, respectively. Compared with 2012, UIW was reduced by 65% in 2016, resulting in the contribution of UIW to CODMn decreased by 1.17 mg L-1. In addition, compared with 2004, UDS decreased by 85% in 2016, and the contribution of UDS to BOD and F. coli decreased by 0.7 mg L-1 and 887 cfu L-1, respectively. Based on the results of APCS-MLR, it was predicted that the concentrations of COD and TP in Honghu Lake would meet the water quality requirements after 2017. However, the rainfall non-point source pollution must be further controlled to achieve the desired level of TN concentration. This study provided an accurate method for analyzing lake water pollution, and the results can provide a valuable reference for optimizing water quality management and pollution control strategies within Honghu Lake.

Water hyacinth biochar and Aspergillus niger biomass amalgamation potential in removal of pollutants from polluted lake water

The excess load of organic and inorganic pollutants in Chanramkudi Lake water creates eutrophication resulting from excess growth and spreading of water hyacinth and bad odor and provides favorable circumstances for the survival of disease spreading insect vectors and possibilities of disease occurrence. The results showed that the suitable temperature and residence time for the conversion of dried biomass of water hyacinth into useful biochar was 350 °C and 60 min, respectively, and 33.6% of water hyacinth biochar (WHBC) at stable organic content basis of 49.2% was produced. The WHBC produced under this condition had physicochemical properties such as 389.8 mmol kg−1 of CEC (Cation Exchange Capacity), 69.1 of C/N, 68.2 of C, 234.7 mg kg−1 of total P, 19.7% of ash, and 59.4% of volatiles with pH 7.9. The metal adsorbing competence of this WHBC with and without A. niger was tested with various concentrations (250, 500, 750, and 1000 mg L−1) of various metal (Cd, Cr, and Pb) containing solutions. The WHBC with A. niger amalgamation (15:3 g) effectively adsorbed the metals even at 1000 mg L-1 such as Cr (91.5%), Cd (95.6%), and Pb (93.9%) than individually. The metals were adsorbed and immobilized in the pores of WHBC and the outer layer of the cell wall of A. niger was observed under SEM analysis with various scaling (50, 100, and 150 µm). Further, the pollutant adsorbing functional groups were found in both WHBC and dead mycelia biomass of A. niger through FTIR analysis. The attained results concluded that the biochar produced from challenging water hyacinth could adsorb and minimize the pollutants with an amalgamation of A. niger. Significantly, more volume (33.6%) of biochar can be derived from water hyacinth. Furthermore, WHBC and A. niger are easily cultivable. Thus, it could be preferably useful for removing real-world organic and inorganic pollutants from polluted water.

A brief study on the physicochemical parameters and the microbial flora of an eutrophic lake: Perungalathur Lake (Peria Eri), Chennai, Tamil Nadu, India

Water is a critical resource in the lives of people who both benefit from its use and who are harmed by its misuse and unpredictability (flooding, droughts, salinity, acidity, and degraded quality). Water is a finite and vulnerable resource. Consequently, consumption of polluted water puts lives and livelihoods at risk because water has no substitute. There are many ways in which water intended for human consumption can get polluted. These include wastes from industries like mining and construction, food processing, radioactive wastes from power generating industries, domestic and agricultural wastes and by various microbiological agents. Water pollution is a serious threat all over the world in the light of limited fresh water availability and increasing generation of waste water being discharged either on land or into rivers, lakes, water bodies or sea thereby polluting the fresh water available in rivers, lakes, water bodies, and groundwater. The water pollution scenario in India is equally critical posing great threat to human health, aquatic life, vegetation and ecological balance. In this paper, the effects of polluted lake water and analyzed by various analytical tests that this lake water was highly contaminated by the open defecation activities and mixture of domestic wastes which has been confirmed by the presence of microbial agents like Escherichia coli and Staphylococcus aureus hence it’s not suitable for human consumption has been proved.

Removal of cyanobacteria and cyanotoxins by ferrate from polluted lake water.

Freshwater cyanobacterial blooms are becoming increasingly problematic microbiological pollutants, especially for the water resource and surface natural lakes. Cyanobacterial blooms, which produce toxins and microcystins, negatively affect the quality of water, animal, and human health, and they have also negative impact on recreational activities. The effect of electrochemically prepared potassium ferrate (green oxidation agent) on the water polluted by cyanobacteria and cyanotoxins was studied. The two most frequently occurring cyanobacterial genus Microcystis and Anabaena and the most toxic and abundant microcystin MC-LR were successfully inactivated and treated by ferrate. Potassium ferrates were applied at different conditions, such as varied hydrodynamics flow of samples, pH, and Fe(VI) concentrations. High detected elimination efficiency was consequently tested on the real water matrix from microbiological polluted natural lake Šaštín-Gazárka in Slovakia. The ferrate application leads to the better chemical, biological, microbiological, and ecotoxicological outcomes.

Effect of design and operational parameters on nutrients and heavy metal removal in pilot floating treatment wetlands with Eichhornia Crassipes treating polluted lake water.

Though having an economic and ecological impact on Marriott Lake management in Egypt, water hyacinth (Eichhornia crassipes) is an aquatic floating macrophyte with a known phytoremediation potential. In order to assess its remediation potential, pilot floating treatment wetlands (FTWs) with E. crassipes were built in duplicates to evaluate the removal of nutrients and heavy metals from the polluted lake water. The experimental design included units with different water depths (15, 25, and 35 cm; D15, D25, and D35, respectively) and plant coverage (90, 70, 50, and 0%; P90, P70, P50, and P0, respectively). The pilot FTWs were monitored over a 7-day operation cycle to identify the optimum combination of design (plant coverage, water depth) and operation (hydraulic retention time; HRT) parameters needed for maximum BOD5, TN, NH4-N, and TP removal. NH4-N removal reached 97.4% in the D25P50 unit after 3 days, BOD5 75% in the D15P90 after 3 days, TN 82% in the D25P70 after 4 days, and TP 84.2% in the D35P70 after 4 days. The open-water evaporation rate was higher than the evapotranspiration rate in the planted units, probably due to the warm climate of the study area. Metals were also sufficiently removed through bioaccumulation in plant tissues in the order of Fe > Pb > Cu > Ni (62.5%, 88.9%, 81.7%, and 80.4% for D25P50, D25P70, D25P50, and D25P90, respectively), while most of the assimilated metal mass was translocated to the plant roots. The biochemical composition of the plant tissue was significantly different between the shoot and root parts. Overall, the FTW with 70% E. crassipes coverage, 25-cm water depth, and an HRT of 3-5 days was identified as the optimum design for effective remediation of the polluted Marriott Lake in Egypt.

Enhanced Phytoremediation of Bisphenol A in Polluted Lake Water by Seedlings of Ceratophyllum demersum and Myriophyllum spicatum from In Vitro Culture.

Bisphenol A (BPA) is a typical endocrine disruptor that causes problems in waters all around the world. In this study, the effects of submerged macrophytes (Ceratophyllum demersum and Myriophyllum spicatum) cultured in vitro on the removal of BPA at two initial concentrations (0.5 mg L−1 vs. 5.0 mg L−1) from Donghu lake water were investigated, using different biomass densities (2 g L−1 vs. 10 g L−1) under different nutrient conditions (1.85 mg L−1 and 0.039 mg L−1 vs. 8.04 mg L−1 and 0.175 mg L−1 of the total nitrogen and phosphorus concentration, respectively), together with the effect of indigenous microorganisms in the water. The results showed that indigenous microorganisms had limited capacity for BPA removal, especially at higher BPA initial concentration when its removal rate amounted to about 12% in 12 days. Addition with plant seedlings (5 cm in length) greatly enhanced the BPA removal, which reached 100% and over 50% at low and high BPA initial concentration in 3 days, respectively. Higher biomass density greatly favored the process, resulting in 100% of BPA removal at high BPA initial concentration in 3 days. However, increases in nutrient availability had little effect on the BPA removal by plants. BPA at 10.0 mg L−1 significantly inhibited the growth of M. spicatum. Therefore, C. demersum may be a candidate for phytoremediation due to greater efficiency for BPA removal and tolerance to BPA pollution. Overall, seedlings of submerged macrophytes from in vitro culture showed great potential for use in phytoremediation of BPA in natural waters, especially C. demersum.

GREEN AGRICULTURE AND BLUE WATER IN CHINA: REINTEGRATING CROP AND LIVESTOCK PRODUCTION FOR CLEAN WATER

Crop and livestock production are essential to maintain food security. In China, crop and livestock production were integrated in the past. Today, small backyard systems are still integrated but the larger livestock farms are landless and largely geographically separated from crop production systems. As a result, there is less recycling of animal manures and there are lower nutrient use efficiencies in the Chinese food production systems. This, in turn, results in considerable losses of nutrients, causing water pollution and harmful algal blooms in Chinese lakes, rivers and seas. To turn the tide, there is a need for agricultural green development for food production through reintegrating crop and livestock production. An additional wish is to turn the Chinese water systems blue to secure clean water for current and future generations. In this paper, current knowledge is summarized to identify promising interventions for reintegrating crop and livestock production toward clean water. Technical, social, economic, policy and environmental interventions are addressed and examples are given. The paper highlights recommended next steps to achieve green agriculture and blue water in China.

Indicative Lake Water Quality Assessment Using Remote Sensing Images-Effect of COVID-19 Lockdown

The major lockdown due to the COVID-19 pandemic has affected the socio-economic development of the world. On the other hand, there are also reports of reduced pollution levels. In this study, an indicative analysis is adopted to understand the effect of lockdown on the changes in the water quality parameters for Lake Hussain Sagar using two remote sensing techniques: (i) spectral reflectance (SR) and (ii) chromaticity analysis (Forel-Ule color Index (FUI) and Excitation Purity). The empirical relationships from earlier studies imply that (i) increase in SR values (band B2) indicates a reduction in Chlorophyll-a (Chl-a) and Colored Dissolved Organic Matter (CDOM) concentrations, and (ii) increase in FUI indicates an increase in Total Suspended Solids (TSS). The Landsat 8 OLI satellite images are adopted for comparison between (i) January to May of year 2020: the effect of lockdown on water quality, and (ii) March and April for years 2015 to 2020: historical variations in water quality. The results show notable changes in SR values and FUI due to lockdown compared to before lockdown and after unlock suggesting a significant reduction in lake water pollution. In addition, the historical variations within April suggest that the pollution levels are least in the year 2020.

Evaluation and variation trends analysis of water quality in response to water regime changes in a typical river-connected lake (Dongting Lake), China

Lake water pollution has caused many serious ecological issues globally. An emerging public concern over water quality deterioration in lakes has heightened the need to evaluate the water quality of lakes at long-term scales, particularly for those with high hydrological alterations. This study combines the Mann-Kendall (M-K) test and self-organising map (SOM) to characterise and evaluate water quality trends in Dongting Lake, China, from 1991 to 2018, before and after the inauguration of the Three Gorges Dam (TGD). Herein, six water quality parameters were selected, namely pH, permanganate index (CODMn), ammonia nitrogen (NH3-N), total nitrogen (TN), total phosphorus (TP), and the five-day biochemical oxygen demand (BOD5). Our results show that the concentrations of TN and BOD5 increase significantly throughout the study period (|Z|≥1.96). The number of abrupt change points for the six water quality parameters in the post-TGD period was greater than that in the pre-TGD period, which indicates an increased risk of water deterioration in the post-TGD period. The SOM results show that the pH values ranged from 7.64 to 7.85 among the four clusters; besides, the concentrations of the remaining water quality parameters from 1991 to 1997 and 2000 to 2003 were relatively lower, suggesting that the water quality in the pre-TGD period was better. The classification of TN and TP ranged from Level Ⅳ-Ⅴ among the clusters, which did not satisfy the level Ⅲ standard for potable water, thereby posing a higher ecological risk to the Dongting Lake. These results indicate the deterioration of the water quality in Dongting Lake during the post-TGD period under the influences of pollution load and hydrological regulation. Therefore, strict controls on the external nutrient loading and hydrological regulations should be considered for water quality management.

The Nutrient Removal Ability and Microbial Communities in a Pilot-Scale Horizontal Subsurface Flow Constructed Wetland Fed by Slightly Polluted Lake Water

A pilot-scale horizontal subsurface flow constructed wetland (HFCW) was established to investigate the feasibility of removing nutrients from natural water in Lake Xijiu, Jiangsu Province, China. The HFCW, planted with reeds (Phragmites communis) and irises (Iris tectorum Maxim), was operated for 227 days. The mean removal efficiency of NH4+-N was 36.7%, of total nitrogen (TN) 70.2%, of total phosphorus 75.3%, of permanganate index (CODMn) 35.8%, and of Chlorophyll a 70.0%. The effluent concentrations of these pollutants were all within the Grade III threshold of China’s water quality standards for surface water. Correlation analysis showed that TN removal was related to the CODMn concentration in the influent (r2 = 0.65) and was closely related to the temperature (r2 = 0.91). The HFCW had a water production efficiency of 98%–99% over the entire operational period, which suggests that it did not block easily. Results from 16S rDNA high-throughput sequencing showed that Proteobacteria (40.65%) dominated at the phylum level. At the genus level, the relative abundance of Nitrosomonadaceae (3.57%) was highest in autumn and the spatial distribution from the front to the back varied slightly from 2.57% to 2.99%. Our results will help researchers to develop optimal designs for HFCW systems to treat slightly polluted water.