Wetland Water Quality Research Articles

Wetland health, water quality, and resident perceptions of declining ecosystem services: a case study of Mount Abu, Rajasthan, India.

Ecosystem services provided by wetlands are essential for communities living near wetlands, especially in an underdeveloped semi-arid landscape. The land use land cover changes and ecosystem degradation and water quality change over the past few decades have had immense effects on declining wetland ecosystem services. With the degradation, it is exerting superfluous effects on wetland communities including loss of livelihood, and decline in other wetland services like fishing, aquaculture, fuelwood, fodder, and many more. The present study attempts to assess the changing nature of wetland health, water quality, and declining ecosystem services of Mount Abu wetlands in Rajasthan, India. For assessing the change of wetland extent, we have used the remote sensing-based data for preparation of land use land cover change from 1992 to 2020. The water samples have been collected from the wetland, and different biophysical parameters of the water have been tested in the laboratory. A questionnaire-based household survey has been conducted to understand the perception of the wetland communities on the loss of ecosystem services over three decades. Further, a correlation and cluster assessment has been conducted to understand the degradation of wetland health in the selected wetlands. The study results indicated deteriorating conditions of wetland health and declining ecosystem services in the study area over the time periods. The land use land cover change analysis indicated a decrease in the spatial extent of the wetlands in the study area. Wetland communities are being affected due to the degradation of wetland health. The study recommended executing a wetland management plan for long-term conservation and livelihood management for the Mount Abu wetlands and communities.

Nitrogen Inversion Model in a Wetland Environment Based on the Canopy Reflectance of Emergent Plants

Reuse of reclaimed water in constructed wetlands is a promising way to conserve water resources and improve water quality, and it is playing a very important role in wetland restoration and reconstruction. This study utilized reflectance spectra of wetland vegetation to estimate nitrogen content in water in the Beijing Bai River constructed wetland, a typically constructed wetland that uses reclaimed water. Canopy reflectance spectra of two dominant plants in the wetland, including reed and cattail, were acquired using a spectrometer (350–2500 nm). Simultaneously, water samples were collected to measure water quality. To establish the appreciate relationship between total nitrogen content (TN) and reflectance spectra, both simple and multiple regression models, including simple ration spectral index (SR), normalized difference spectral index (ND), stepwise multiple linear regression (SMLR) model, and partial least squares regression (PLSR), were adopted in this study. The results showed that (1) compared with simple regression models (SR and ND), multiple regressions models (SMLR and PLSR) could provide a more accurate estimation of TN concentration in the wetland environment. Among these models, the PLSR model had the highest accuracy and was proven to be the most useful tool to reveal the relationship between the spectral reflectance of wetland plants and the total nitrogen consistency of wetland at the canopy scale. (2) The inversion effect of TN concentration in water is slightly better than that of wetland vegetation, and the reflection spectrum of the reed can predict TN concentration more accurately than that of cattail. The finding not only provides solid evidence for the potential application of remote sensing to detect water eutrophication but also enhances our understanding of the monitoring and management of water quality in urban wetlands using recycled water.

Tracer-aided identification of hydrological and biogeochemical controls on in-stream water quality in a riparian wetland

In-stream water quality reflects the integrated results of hydrological mixing of different water sources and associated biogeochemical transformations. However, quantifying the relative importance of these controls is often challenging, particularly in riparian wetlands due to complex process interactions and marked spatio-temporal heterogeneity in environmental gradients. Here, we established a two-step method to differentiate the dominance of hydrological and biogeochemical controls on water quality in a riparian peatland in northern Germany. First, an isotope-based mixing model was developed for distributed modelling of in-stream water balance over a two-year period. The simulation showed the predominance of groundwater inflows for most of the time period, while lateral inflows and channel leakage became more influential in mid-summer, as stream-groundwater connectivity weakened due to declining groundwater levels. A moderate downstream shift from groundwater to lateral inflow was also observed due to the changing channel network geometries and inflow from field drains. The mixing model was then further applied to predict the in-stream concentrations of nutrients, major ions and trace elements. The predicted concentrations were assumed to be those resulting from hydrological mixing only, while influence of biogeochemical controls were reflected by the prediction deviation from observation. Accordingly, 15 water quality parameters were grouped based on their simulation performances into hydrologically-controlled (Cl–, Mg, Na, K, and Si), biogeochemically-controlled (DOC, SO42−, Mn, and Zn), or controlled-by-both (SRP, NO3-N, Ca, Fe, Al, and Cu). The mixing modelling not only reproduced the spatiotemporal in-stream water balance with finer process conceptualisation, but also provided a generic method to quantitatively disentangle the relative strength of hydrological and biogeochemical controls. Such a method can be employed as a robust learning tool before extending a hydrological model for water quality simulation, as when, where and how strong biogeochemical controls are exerted provides a strong indicator on which dominant processes need to be conceptualised.

Remotely sensed data for estimating chlorophyll-a concentration in wetlands located in the Limpopo Transboundary River Basin, South Africa

Wetlands in semi-arid regions are highly productive and biologically diverse ecosystems that contribute significantly to livelihood and economic development and play a substantial role in sustaining rural livelihoods. These ecosystems are not only rich in biodiversity, but also predominantly valuable in terms of the services they provide to people, including water security, hydrological regulation, and other services. Chlorophyll-a concentrations and associated dynamics in two tropical wetland systems were estimated in the Makuleke and Nylsvlei wetlands. The Makuleke and Nylsvlei wetlands are in the Limpopo Transboundary River Basin, South Africa. Moderate-resolution Landsat 8 images for September 2018 and June 2019 and in situ field measurements were used to estimate and map chlorophyll-a concentration from the two wetlands. Landsat-derived chlorophyll-a concentrations were validated using field-derived chlorophyll-a measurements. Validation was implemented to assess the consistency of the remotely sensed chlorophyll-a estimates. The relationship between field-measured chlorophyll estimates and Landsat-derived chlorophyll estimates was determined using the coefficient of determination (r-square: R2) and the root mean square error (RMSE). The results showed that the Makuleke wetland had low estimates of Chl-a during September 2018. The variation of Chl-a concentration in Makuleke ranged from 0 to 1.15 μg/L, whereas for Nylsvlei the wetland range varied between 0 and 1.42 μg/L, for the period under study. The spatial characterization of Chl-a concentration varied significantly between the two wetlands, with much of it concentrated along the wetland shorelines. The finding of this study underscores the relevance of remotely detected data in the evaluation and routine monitoring of wetland water quality, a previously challenging task within situ measurements.

Impact of Land Use Types at Different Scales on Surface Water Environment Quality and Its Driving Mechanism

As an important carrier of human activities, the spatial type of land use has an important impact on the surface water environment. Taking the Ruoergai wetland as an example, based on object-oriented remote sensing interpretation of land use types combined with water quality examination data, this study analyzed the impact and driving mechanism of land use types at different scales on the surface water environment at the small watershed and buffer scale. ① It was found that the water quality of the Ruoergai wetland could been classified as water grade V, and it was slightly eutrophic as a whole. The main pollutants were total nitrogen(TN) and phosphorus(TP), and the pollution originated from domestic sewage and grazing. ② The environmental quality of surface water was closely related to land use types. There was a negative correlation between chemical oxygen demand(COD) and the proportion of water area, a positive correlation between TN and the proportion of swamp area, and a negative correlation between total TP. ③ There was a significant correlation between spatial land use types at different scales and surface water environment. The land use type within a buffer of 1000 m had the highest interpretation degree for all factors, the land use type within a buffer of 200 m had the greatest interpretation degree for COD, the land use type within a buffer of 500 m zone had the greatest interpretation degree for TP and TN, and the land use type within a buffer of 800 m had the greatest explanation for Chl-a. The results of this study showed that the Ruoergai wetland wetland had a certain purification effect on pollutants and eutrophication. However, different land use types had different effects on different pollutants. The water body had a purification effect on Fe2+, COD, and Chl-a, and the swamp had a purification effect on TP but a cumulative effect on TN. Thus, the small-buffer zone(≤ 1000 m) land use type should be controlled, the water body and swamp areas should be controlled, the self-purification capacity of wetland waters should be improved, and the surface water environment of the Ruoergai wetland should be further protected and repaired.

Assessment of Surface Water Quality of an Urban Wetland: Thalangama Wetland, Colombo, Sri Lanka

Thalangama wetland is situated within the Kelani river basin, Colombo District, Sri Lanka. It is one of the most attractive landscapes in Colombo that provides a wide range of ecological, social and economic functions. Wetland water supports aquatic life and is being prominently used for agriculture and bathing and contact recreational activities without knowing if the water quality is appropriate for such uses. This study was therefore conducted to assess the surface water quality of Thalangama wetland using key-physicochemical parameters and to examine the suitability of wetland waters for bathing and contact recreational water, aquatic life, irrigation and other agricultural activities. A total of 10 water quality parameters covering temperature, pH, salinity, TDS, EC, DO, BOD, COD, nitrate, and total phosphate were measured at eight sampling sites of the wetland. The study was conducted in August 2020. The spatial variation of water quality parameters was assessed using one-way ANOVA followed by Tukey’s pairwise comparison. Results were compared with ambient water quality standards of Sri Lanka. The study revealed that the surface water quality parameters including temperature, EC, TDS, DO, BOD, COD, nitrate and total phosphate show a significant spatial variation among the sampling sites. Surface water pH and BOD at all the sampling sites were within the ambient water quality standards for water suitable for bathing and contact recreational water and water suitable for aquatic life, irrigation and agricultural activities. EC at all the sampling sites were within the limits of water suitable for irrigation and agricultural activities. Nitrate and total phosphate concentrations at all the sampling sites were within the limits of water suitable as bathing and contact recreational water and water suitable for aquatic life. DO at six out of eight sampling sites were within the limits of water suitable as bathing and contact recreational waters and water suitable for aquatic life, irrigation and agricultural activities. COD at all the sampling sites were not within the limits of water suitable as bathing and contact recreational water and water suitable for aquatic life. The study identifies agricultural practices, livestock rearing, construction activities and urban discharges as major anthropogenic influences that degrade the surface water quality of the wetland. Hence, the study determines the necessity for effective management of the surface water of Thalangama wetland to prevent pollution and to ensure the water quality of the wetland is within the recommended standards.
 Keywords: Urban wetlands, Surface water quality, Spatial variation, Physicochemical parameters, Ambient water quality standards

Impact of Land Cover Changes on the Wetland Ecosystem Water Environment Using Soft Computing Methods

Economic growth is accelerating in the entire world due to new inventions and advancements in the field of science and technology. The technology is progressing at a rapid pace and resulting in the infrastructure and technical progression of each nation. The utilization rate of land in the world has also increased substantially where the cultivated land is used for the development of industries and buildings. This land occupancy is alarming for the environment, and it is impacting the ecosystem of the earth in many adverse ways. In this study, the impact of land cover changes on the wetland ecosystem water environment has been studied in depth using soft computing techniques. The water environment data of the wetland ecosystem are obtained from real-world scenario and are mined using a particle swarm K-means clustering approach based on chaos search. The water environment assessment approach is used to analyze the influence of land cover changes on the water environment of the wetland ecosystem. The findings of this research work reveal that the cultivated land in the wetland is steadily decreasing, and the fertile forestland is steadily decreasing in the early stages and gradually increasing in the latter stages. The wetland water quality is gradually degrading over the period of time. The outcomes of the study demonstrate that a nonpoint source of pollution produced by land-use changes is the most important factor, which is affecting water quality. The analytical results’ accuracy is as high as 0.98 when compared to the real-world circumstances.

Temporal and spatial variability of water quality in an urban wetland and the effects of season and rainfall: a case study in the Daguan Wetland, China.

Urban wetlands provide multiple functions including water treatment, recreation, and education, but they are also highly vulnerable, so it is important to monitor wetland water quality to ensure wetland health. In this study, water quality parameters of an urban wetland and rainfall were monitored at 6 sites for 1year. The correlation analysis of water quality parameters and spatial-temporal variability analysis of water quality were carried out. Besides, the effects of season and rainfall on the wetland water quality were evaluated by the comprehensive water quality identification index (CWQII). These results have shown that there is a significant correlation between nutrient pollutants and Chl-a. Wetland water quality changed with the seasons, but it also varied due to changes in rainfall and location. The water quality of the shallow areas both had high susceptibility and response to seasonal changes and rainfall, but the water quality of the deepwater area was relatively stable. The CWQIIs in different seasons were ranked: Winter (5.98) > spring (4.67) > autumn (4.66) > summer (4.26), and the CWQIIs of different rainfall intensities were ranked: torrential rain (5.09) > heavy rain (4.88) > light rain (4.50) > no rain (4.39) > moderate rain (3.95). The results of this study distinctly explained the effects of season and rainfall on water quality in an urban wetland in a subtropical monsoon climate zone and would be helpful to the policymakers and concerned authorities in developing better water quality management strategies for these wetlands.

Assessment of water quality and overall biodiversity of certain wetlands of Sivasagar urban area

Various physic-chemical parameters such as ph, Dissolved Oxygen (DO), free CO2 are commonly used criteria for water quality assessment. It provides information about the overall health of the water bodies. Biodiversity of macro-invertebrates and physic-chemical water quality parameters of Juliva fishery and Moribeel wetland of Sivasagar district of Assam were assessed from different sampling sites monthly from April, 2017 to April, 2018. By studying macro-invertebrates diversity of the wetland as bioindicator, we have assessed the overall quality of these water bodies, mainly about their pollution status.

Groundwater discharge drives water quality and greenhouse gas emissions in a tidal wetland

Wetlands play an important role in the global carbon cycle as they can be sources or sinks for greenhouse gases. Groundwater discharge into wetlands can affect the water chemistry and act as a source of dissolved greenhouse gases, including CO2 and CH4. In this study, surface water quality parameters and CO2 and CH4 concentrations were evaluated in a tidal wetland (Hunter Wetlands National Park, Australia) using time series measurements. Radon (222Rn), a natural groundwater tracer, was used to investigate the role of groundwater as a pathway for transporting dissolved CO2 and CH4 into the wetland. In addition, water-to-air CO2 and CH4 fluxes from the wetland were also estimated. The results showed a high concentration of radon in wetland surface water, indicating the occurrence of groundwater discharge. Radon concentration had a strong negative relationship with water depth with a determination coefficient (R2) of 0.7, indicating that tidal pumping was the main driver of groundwater discharge to the wetland. Radon concentration also showed a positive relationship with CO2 and CH4 concentrations (R2 = 0.4 and 0.5, respectively), while the time series data revealed that radon, CO2, and CH4 concentrations peaked concurrently during low tides. This implied that groundwater discharge was a source of CO2 and CH4 to the wetland. The wetland had an average water-to-air CO2 flux of 99.1 mmol/(m2·d), twice higher than the global average CO2 flux from wetlands. The average CH4 flux from the wetland was estimated to be 0.3 mmol/(m2·d), which is at the higher end of the global CH4 flux range for wetlands. The results showed that groundwater discharge could be an important, yet unaccounted source of CO2 and CH4 to tidal wetlands. This work has implications for tidal wetland carbon budgets and emphasizes the role of groundwater as a subsurface pathway for carbon transport.

Effects of inundation on water quality and invertebrates in semi-arid floodplain wetlands

Floodplain wetlands play a significant role in the storage of sediment and water and support high levels of nutrient cycling that is driven by intermittent inundation. In regulated rivers, there is often a reduction in the frequency and duration of inundation and managed floodplain inundation is used as a tool to help restore wetlands. It is important to quantify the outcomes of re-introducing water to floodplain wetland systems. We examined the effects of environmental floodplain watering on water quality and three groups of invertebrates, including benthic and pelagic microinvertebrates and macroinvertebrates, in two wetlands systems on the Gwydir River system in the north of the Murray-Darling Basin. We hypothesised that a wetland inundated for longer periods of time would have altered water quality and support a greater richness and abundance of invertebrates, thus altering their assemblage structures. Water quality and the assemblage structure of all three invertebrate groups in the wetlands was significantly influenced by the time since connection (TSC) to their rivers and therefore the length of inundation. However, the response of water quality and the microinvertebrate assemblages to TSC differed between the two wetlands. Water quality was affected by an increase in six variables, including the nutrient TN and a decrease in the nutrient SRP. Microinvertebrate abundance was positively associated with TSC, but the abundance of macroinvertebrates was not. The relationships demonstrated between TSC and invertebrates indicate that the duration of inundation is important in maintaining the ecology and food webs in these and other semi-arid floodplain wetlands.

Long-term water quality response to increased hydraulic loadings in a field-scale free water surface constructed wetland treating domestic effluent

There is limited understanding of how constructed wetland (CW) water quality may change over time in response to increased wastewater nutrient and hydraulic loadings. We evaluated long-term water quality trends and drivers for a full-scale (8.19 ha) free water surface CW that was developed in 2001 for the treatment of increasing amounts of pre-treated domestic wastewater from the township of Mount Barker, South Australia. Water quality parameter concentrations and loads, hydraulic loadings rates, trend direction assessments (TDAs), and water quality parameter removal efficiencies were analysed over the study period. The wetland received an annual average loading rate of 947, 19644, 31039, 18140, 2985, and 807 kg year−1 for BOD5, TN, NH4–N, TKN-N, NOx-N, and TP respectively and removed on average 8%, 72%, 73%, 78%, 12% and −246% of these loadings respectively. The average influent concentrations for the study period were 2.6, 42.3, 40.6, 35.9, 9.0, and 1.9 mg L−1 for BOD5, TN, NH4–N, TKN-N, NOx-N, and TP respectively. Average concentration removal rates over the study period were 50%, 39%, 40%, 15%, −216% and −600.5% for TN, NH4–N, TKN-N, NOx-N, BOD5 and TP respectively, suggesting that nitrogen was only partly assimilated by the wetland and it was a source of organic material and phosphorus. Using seasonally and inflow rate adjusted data, TDAs predicted virtually certain increases in TN, NH4–N, and TKN-N influent concentrations over time, a decline in NOx-N, no trend in BOD5, and a possible decreasing trend in TP. The inflow explained variance accounted for approximately 50% of the variation in TN, NH4–N and TKN-N effluent concentrations. Annual removal efficiencies of N declined with increasing hydraulic loads, and hydraulic loading rates varied with management practices. Seasonal analysis showed that N removal was greater during summer and lower in winter. Due to local population growth and various management practices, hydraulic loading is variable and has often exceeded design targets. Our findings indicate the long-term performance of CWs need to be closely monitored, as water quality can deteriorate due to increased hydraulic loadings.

Studies on water quality and sustainable livelihood role of wetland, Maran Chaur, Darbhanga

Darbhanga district is reach in wetlands, which play a significant role in livelihood resources due to highly productive flora and fauna. Maran chaur is an important wetland in the Darbhanga district. This water body is not used for fisheries only, but makhana (Euryale ferox) and singhara (Trapa bispinosa) are also cultivated. The abundant water resource is used for irrigation and another purpose, thus provide the basis of livelihood for human beings. The main objective of the current study was to analyze water Physico-chemical parameters and highlight the value of wetlands and their products in sustaining livelihood in Darbhanga. The surveys were conducted on a micro-area approach for assessing wetland product-based economy and their role in sustaining livelihood. All the physico-chemical parameters were found within the permissible limit. The result of sample survey data analysis and empirical assessment becomes the basis of this study. The paper takes into account some important facets of Maran chaur, Darbhanga in relation to socio-economic sustainable regional development.

Impact of nutrient enrichment on water quality of a tropical Ramsar Wetland | IJAAR 2022

Impact of nutrient enrichment on water quality of a tropical Ramsar Wetland | IJAAR 2022

How Agriculture, Connectivity and Water Management Can Affect Water Quality of a Mediterranean Coastal Wetland

The Natural Park of Albufera (Valencia, Spain) is an important Mediterranean coastal wetland that suffers continuous environmental effects from human activities and water uses, mainly related to agriculture and urban/industrial sewage discharges. The aim of this research was to assess the water quality of the different aquatic environments of this wetland, taking into account the connection between them, the agricultural impact and the management of irrigation water. The UE Water Framework Directive was followed in order to evaluate the ecological and trophic status of water systems. Spatial approaches were used to integrate physicochemical data into GIS vector layers to map the more problematic points of pollution. The results showed a globally eutrophic system with poor ecological potential. The wetland is nutrient-overloaded during the entire rice cultivation period. Good-quality water inputs are deficient, since the river network already has high levels of nutrients and pollutants, especially in the northern area, where river water is mixed with inappropriate effluents from wastewater treatment plants. Agriculture and water management affected the area intensively up to the Albufera lake, modulating most of the studied variables. The information gathered here can help to optimize the global study and management of the coastal Mediterranean wetlands, which are highly linked to agriculture.

An Evaluation of the Khubelu Wetland and Receiving Stream Water Quality for Community Use

Wetlands in Lesotho are at the headwaters of some shared river basins like the Orange-Senqu River basin. These wetlands are threatened by various anthropogenic activities which are compromising their water quality. This study assessed the water quality status of the Khubelu wetland and stream using various water quality parameters to determine its suitability for domestic use, irrigation, and livestock watering. This was a preliminary research study on the suitability of the stream water for various uses in the study area. Calcium was the most concentrated cation in the stream (8.20 mg/L to 16.8 mg/L), followed by magnesium (7.29 mg/L to 12.51 mg/L), with sodium and potassium showing minimum values. The chemical oxygen demand values were in the range of 48 to 160 mg/L. All parameters were within the EU and WHO ranges for drinking water, except EC, DO, BOD, COD, and PO4 levels. The Khubelu wetland water quality index (WQI) had a value of 93, whereas the stream WQI value was 107. The sodium Adsorption Ratio (SAR) values for the wetland and stream were 3.83 and 1.04, respectively, whereas the Soluble Sodium Percentage (SSP) ranged from 18.19 to 39.25%. The stream water quality was acceptable for animal watering and crop irrigation, whereas wetland water would be acceptable for animal watering and would present some challenges for crop irrigation purposes due to the magnesium hazard it poses. The implications for the management of the wetland are discussed.

Evaluation of Water Quality in Thrissur-Malappuram Kole Wetlands of Kerala using Water Quality Index

This study assessed water quality of Kole wetlands in Thrissur-Malappuram which serves as a natural water reservoir. The Kole wetland water samples were collected from the four study areas and the chemical parameters were analysed. The Water Quality Index (WQI) was computed by weighted arithmetic index method. The WQI and possible usage of each category was analysed. It was observed that WQI of the site-1 and site-3 indicated “very poor” and “poor” water quality status, respectively. The site-2 represented very good status in water quality index and the site-4 indicated high pollution regarding WQI status and categorised as “unfit for consumption” and need proper treatment before use

Wetland Ecotourism Development Using Deep Learning and Grey Clustering Algorithm from the Perspective of Sustainable Development.

The purpose is to promote the sustainable development of wetland ecotourism in China and plan the passenger flow in different tourism periods. This work selects Zhangye Heihe wetland ecotourism spot as the research object. Firstly, the two single wetland ecotourism Demand Prediction Models (DPMs) are proposed based on the time series of the optimized Fuzzy Clustering Algorithm (FCA), grey theory, and the Markov Chain Method. The proposed wetland ecotourism DPM simulates and predicts the ecotourism passenger flow of wetland-scenic spots and verifies the maximum passenger flow. Then, a hybrid model combining the above two single models is proposed, namely, the wetland ecotourism DPM based on an optimized fuzzy grey clustering algorithm. Further, the proposed three models predict the passenger flow in wetland ecotourism spots from 2015 to 2019. A wetland Water Quality Evaluation (WQE) model based on Deep Learning Backpropagation Neural Network (Deep Learning (DL) BPNN) is proposed to evaluate the water quality in different water periods. The results show that the hybrid model's Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE) are 1.25% and 0.2532. By comparison, for two single models, the MAPE is 11.67% and 1.45%, respectively, and the RMSE is 0.2526 and 0.1652, respectively. Therefore, the mixed hybrid has the highest accuracy and stability. The water quality of the scenic spot in the wet season is obviously better than that in the dry season and flat season. It is suggested that the natural environmental factors, such as water quality and passenger flow in different periods, should be considered when formulating ecotourism development strategies.

Influence of saline intrusion on the wetland ecosystem revealed by isotopic and hydrochemical indicators in the Yellow River Delta, China

Yellow River Delta wetland is a nature reserve with important ecological function and service values. It is of great significance for regional ecological protection and species diversity maintenance to systematically evaluate the impact of saline intrusion on wetlands. Based on the sampling campaigns for precipitation, seawater, river water and wetland water in dry, transition and wet season, this study aims to assess the temporal and spatial characteristics of hydrochemistry and water quality in wetland areas and quantify the ecological risks brought by saline intrusion. Isotopic evidence shows that wetland water is affected by intense evaporation, and its source has significant seasonal variation. Piper diagram suggests that the hydrochemical characteristics of wetland water are controlled by the supply from Yellow River water and saline intrusion. Water quality assessment based on metrics of soluble sodium percentage (Na %), sodium adsorption ratio (SAR) and Kelley's radio (KR) indicates that the sodium and salinity hazards caused by saline intrusion lead to negative effects on plant growth for most wetland sites. The risk from high salinity is more serious than that from sodium hazard for the wetland ecosystem. From dry to wet season, water quality in wetlands shows a pronounced trend of deterioration. End member mixing analysis (EMMA) based on principal component analysis (PCA) is employed to quantify the spatio-temporal characteristics of saline intrusion. The results show that the proportion of seawater in wetlands increases at first and then decreases along the stream direction, reflecting the influence of hydrogeological and hydrodynamic variation on water interaction. The proportion of seawater in wetland water ranges between 0 % and 11.86 %, but it poses a severe threat to water quality and ecosystem safety in wetland area. This study will provide insights for environmental risk assessment and water resources management in coastal wetlands.

Using physicochemical and biological parameters for the evaluation of water quality and environmental conditions in international wetlands on the southern part of Lake Urmia, Iran.

The Kani Barazan and Yadegarlou wetlands in the southern part of Lake Urmia (Iran) have been substantially modified due to human activities and anthropogenic use. In recent years, freshwater-based eco-biological studies to recognize the quality of water resources have been greatly expanded. Microalgae and Cyanophyta are considered important bioindicators for the evaluation of water quality and wetland health worldwide. Herein, 22 microalgae and 5 Cyanophyta genera were identified in both wetlands, in which Cyanophyta has mainly caused blooms. Principal components analysis (PCA) was carried out based on links between the distribution of microalgae and Cyanophyta with physical andchemical parameters. The data showed that depth, turbidity, and the temperature had a significant influence on the microalga and Cyanophyta communities in both wetlands. Based on the biological properties, it seems that the Kani Barazan and Yadegarlou international wetlands experience meso-eutrophic conditions. The integration of the physical, chemical and biological parameters with the water quality index (WQI) revealed that both wetlands were polluted as a consequence of human activities.Moreover, a close relationship between WQI and the biological parameters was documented. Thus, we concluded that microalgae and Cyanophyta communities, their abundance patterns, and water quality changes could provide valuable data for the conservation of theKani Barazan and Yadegarlou international wetlands.