ASSESSING THE LAKE WATER QUALITY AND EUTROPHICATION USING CHEMICAL PARAMETERS – A CASE STUDY

The study of tadpole assemblages allows inferring habitat availability and using their occupation as a means of proxy for the effective reproduction of the species, contributing to complementary information for the study of their adult forms. Environmental variables, represented by abiotic variables, vegetation structure, matrix management, and landscape elements, affect species having reproductive modes associated with oviposition and development in bodies of water. In the Orinoco region, most amphibians have complex life cycles and deposit their eggs in highly dynamic lentic bodies of water. Therefore, it is important to know how larval assemblages change over short periods of water accumulation and their relationship with environmental variables. Fieldwork was conducted during 9 weeks of larval sampling, from the beginning of the rainy season. We evaluate changes in anuran assemblages associated with water accumulation in five temporary water bodies of anthropogenic (road or pasture) and natural (savanna or gallery forest) origin. Twenty environmental variables were evaluated and measured in the center of each water body. Of these, nine landscape variables were measured only once during the study. The other eleven variables, representing management practices, physicochemical and structural characteristics of the water bodies, were measured weekly during the 3 months of sampling. We explored differences in the structure and diversity of larval-stage anuran assemblages using statistical tests suitable for small sample sizes (i.e., permutational multivariate analysis of variance PERMANOVA and the distance-based linear modeling DistLM). Of the 14 species found, two species had remarkedly high abundances from whichRhinella humboldti(19% of the total tadpole abundance) was a generalist inhabiting the natural and anthropogenic water bodies, whileLeptodactylus insularum(18% of the total tadpole abundance) was a specialist at a natural pond in the savanna. The natural water bodies contained the highest number of species (between 10 and 12) and a total abundance of larvae (between 847 and 485 individuals). In contrast, the anthropogenic water body tracks generated by tractors were only occupied by two species with 50 individuals in total, while the water body generated by the trampling of cattle in pastures had three species with 474 individuals. These three species that inhabited the anthropogenic puddles were also found in the natural ponds and none of the eight species of hylids inhabited the puddles. In each field trip, all the tadpoles were collected from the sampled bodies of water. However, a week later, we found that each of the water bodies had been recolonized by four species (Leptodactylus fuscus, Leptodactylus fragilis, Elachistocleis ovalis,andR. humbolti). The variables with the highest explanatory power on the variation of anuran assemblage structure throughout all the water bodies were height of plants, number of cattle, distance to the nearest native forest edge, distance to an anthropic lentic body of water, distance to a natural lentic body of water, and pH. The bodies of water immersed in the natural cover were more diverse and had a greater degree of spatial and temporal species turnover. Our study calls for the importance of understanding the turnover of larval stage anurans over short periods, associated with water accumulation, in highly dynamic systems such as natural ponds and anthropogenic puddles. The importance of species traits and local processes is also highlighted, from environmental variables to human management activities, in the conservation of amphibian assemblages.

In Australia and worldwide, open cut mining has become increasingly common over the last few decades through changes in excavation technology and ore economics. However, such operations frequently leave a legacy of open mine pits once mining ceases. Pit lakes will then form in mine pits that extend below the water table when dewatering operations cease. Pit lake waters are typically contaminated with metals, metalloids, saline or acidic/alkaline and rarely approach natural water body chemistry. Physically, pit lakes have unique bathymetries, are often strongly wind sheltered and have very small catchments. Nevertheless, pit lake waters often constitute a vast resource but of limited beneficial use (due to water quality issues); with a potential to contaminate regional surface and ground water resources. Water in pit lakes has the potential to be useful for a range of purposes in the Australian context of characteristic hot, dry climate and relatively few natural water bodies. Consequently, pit lakes can be seen to represent either a significant liability or a water resource to mining companies and regional communities. However, the lack of knowledge on pit lakes continues to hinder their proper management. This paper summarises the limited information currently available on water quality associated with Australian pit lakes. Information on pit lake occurrence, distribution and water quantity and quality is not nationally collated and requires immediate and ongoing attention from both mining companies and regulating authorities. Lack of a readily available database for pit lake occurrence, distribution and water quality fails to realise the potential for these water resources by both mining companies and Australian communities. Lack of access to pit lake quantity and water quality data may also lead to failure to manage this significant source of mining environmental risk.

Rivers adjacent to industrial zones usually suffer from severe pollution issues. Industrial wastewater that has undergone sewage treatment processes may be legally discharged into rivers under water quality permits. Previous studies have frequently employed isotopic tracers to identify potential contaminants for pollution control. Conventional radiogenic isotopes utilized in tracing studies cannot discern whether the source is untreated (primary) industrial wastewater, which can have serious impact to the environment. By analyzing the iron (Fe) and molybdenum (Mo) isotopic compositions in original industrial wastewater and treated effluent, this study aims to investigate whether the heavily polluted Agongdian River is contaminated by the untreated wastewater. Based on the results from this study, the original industrial wastewater exhibits higher concentrations of metallic elements and heavier Fe and lighter Mo isotopic compositions, compared to the treated effluent. Consequently, it appears that Agongdian River water indeed exhibits evidence of untreated industrial wastewater. Furthermore, the volume of original industrial wastewater entering the river can be estimated from these results. This research offers a more precise and accurate approach to monitor potential industrial wastewater pollution in natural water bodies, contributing to the goal of environmental protection and sustainable development.

The Yihe River is an important river in Shandong Province, China. It is a catchment river for the South-to-North Water Diversion Project (SNWDP-ER), providing a variety of benefits and ecosystem services, such as flood and drought regulation, fishery and aquaculture, drinking water sources, and biodiversity conservation. In order to objectively reflect the status and changing trend of water environmental quality of the Yihe River, reduce the cost of detection, and improve the efficiency of water quality evaluation, samples were collected at 8 sampling sites in the 220km main stream of the Yihe River from 2009 to 2019. The spatiotemporal variations of 10 water quality indicators were analyzed, including pH, water temperature (WT), dissolved oxygen (DO), 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total phosphorus (TP), ammonia nitrogen (NH3-N), nitrate (NO3-N), fluoride (F-), and sulphate (SO42-). The water quality index (WQI) was used to evaluate the spatiotemporal water quality changes, and the minimum WQI (WQImin) model consisting of five key indicators, i.e., NH3-N, BOD5, DO, SO42-, and WT, was built by using stepwise multiple linear regression analysis. The results indicated that the water quality indicators in the Yihe River showed significant spatiotemporal variations. With the exception of the COD and TP, the other water quality indicators conformed to the Class I or II standards of China, indicating that the water quality of the Yihe River was better than most natural water bodies. Seasonally, the WQI was better in the autumn and higher in the upstream area compared to the downstream. The water quality remained at the "good" level. The weighted WQImin model performed well in evaluating water quality, with coefficient of determination (R2), mean square error (MSE), and percentage error (PE) values of 0.903, 3.05, and 1.70%, respectively.

The study was carried out to assess the pollution, impact, and risk level to the surface water environment of pollutants in the water bodies of Soc Trang province, Vietnam. The parameters for evaluating surface water quality and risks included temperature, pH, TSS, DO, BOD, COD, NH4+-N, NO2--N, NO3--N, PO43--P, Cl-, Fet, and coliform. Surface water samples were collected at 35 locations with a frequency of six times (February, April, June, August, October, and December) in 2022. The water quality index (WQI), impact and risk level (risk quotient or RQ, RQ-F), correlation analysis, and principal component analysis (PCA) were utilized in the study. The results show that the surface water has been seriously polluted due to organic matter, nutrients, microorganisms, iron, and salinity. The values of WQI in the dry and rainy seasons fluctuated between bad and very good, indicating that surface water quality is suitable for water transport and other purposes with higher quality requirements. TSS, COD, Fet and coliform have a high impact and risk for the environment in this study area. There were no environmental impacts and risks to NO3--N. Locations with many high-risk pollutants were mainly distributed in residential and coastal areas. The significant negative correlation between the WQI and RQ indicated that the lower the WQI, the higher the environmental risk. The PCA results show that at least six polluting sources affected water quality and caused environmental risks. The results of this study contribute essential and valuable information for improving water quality in the study area through the assessment of environmental impacts and risks. Doi: 10.28991/CEJ-2023-09-08-03 Full Text: PDF

Changes in the water quality, sediment, and the presence of heavy metals in the environment have a close links with human activities including the presence of pollutants in the mangrove ecosystem. The purpose of this study is to compare water and sediment quality as well as heavy metal pollution from lead (Pb) in mangrove ecosystems affected by anthropogenic activities (oil palm plantations and mining) in South Kalimantan. The research was carried out for 4 months (June until September 2019) from four villages (Kuala Tambangan, Bunati, Angsana and Setarap) in South Kalimantan Province. The purposive sampling method is used for sampling, which is determined in estuary, middle and inland parts, based on the area division of mangrove ecosystem. Data analysis was performed descriptively while differences in each location were tested using bivariate analysis (Pearson). The results showed that the water quality at the four observation sites was above the standard of Government Regulation number 82 of 2001. There are four values with the highest parameters found in the village of Kuala Tambangan, the first is total dissolved solids (TDS) that reaching ± 8.005 mg / L, nitrite (NO2) as N (± 0.13 mg/L), nitrate (NO3) as N (±0.11 mg/L) and color levels that reach ±129.33 ptCo. The other two highest parameters in Setarap Village are turbidity and dissolved oxygen. Turbidity value reaches ± 16.01 NTU while dissolved oxygen (DO) value is around ±5.92 mg/L. The highest pH value can be found in Bunati Village (± 7.54). The average value of heavy metals in Lead (Pb) is also above the standard of the Minister Decree of Environment in 2004, recorded in waters 0.04 - 0.36 mg/L (highest in Angsana Village ±0.31 mg/L) and sediment 0.01 - 17.43 mg/L (highest in Angsana Village ±15.05 mg/L). The highest water content in sediment comes from Kuala Tambangan village (±6.6%), while the highest organic sediment content is found in Angsana village (±7.8%). Bivariate analysis results used to determine differences between sampling locations showed that the levels of Nitrite (NO2) as N (α = 0,000), Nitrate (NO3) as N (α = 0,000)), pH (α = 0,000), Color (α = 0,000), and Dissolved Oxygen (DO) (α = 0,000), sediment water content (α = 0,000) and heavy metal Pb content in water and sediment (α = 0,000) are differ between mangrove ecosystems in Angsana and Setarap Village.

Objective To investigate the distribution of gross α and gross β radioactive levels in drinking raw water from different regions of Guangdong province, and to establish the radioactive level base line value in raw water. Methods The samples from 191 drinking water sources in use in Guangdong province were collected in rainy season and dry season, respectively, and determined and analyzed under the standard examination method for drinking water-radiological parameters (GB/T 5750.13-2006). The levels of gross α and gross β radioactivity were evaluated under the standard for drinking water quality (GB 5749-2006). Results A total of 377 raw water samples were taken, including 189 samples in rainy season and 188 samples in dry season, in which 186 samples were matched between rainy season and dry season. In dry season, the gross α levels ranged from 0.008 Bq/L to 0.582 Bq/L, averaged at (0.034±0.060) Bq/L, while the gross β levels ranged from 0.014 Bq/L to 0.637 Bq/L, averaged at (0.108±0.091) Bq/L. In rainy season, the gross α levels ranged from 0.008 Bq/L to 0.402 Bq/L, averaged at (0.045±0.064) Bq/L, while the gross β levels ranged from 0.014 Bq/Lto 0.848 Bq/L, averaged at (0.125±0.128) Bq/L. The gross α and gross β radioactivity levels of other samples were much lower than the guidance values in the national radioactivity standards on drinking water radioactivity, except for a sample from Shanwei area. The gross α and gross β radioactivity levels in the rainy season were higher than in the dry water season, and the gross α radioactivity levels in the rainy season were significantly higher than in the dry water season. There were significant differences in gross α and gross β radioactivity levels in rainy(Frainy season=1.819, 2.709, P<0.05) and dry season (Fdry season=1.985, 8.461, P<0.05)in different water systems, and the levels of gross α and gross β radioactivity in the rivers in western Guangdong were the highest. The gross α and gross β radioactivity levels of groundwater in rainy season were higher than in river water and lake water, and the gross α and gross β radioactivity levels in river water were higher than in lake and reservoir water, with the statistically significant differences(Ftotal α=39.323, Ftotal β=25.911, P<0.05), the gross α and gross β radioactivity levels in dry season were higher than in river water and lake water, with the statistically significant difference(Ftotal α=11.520, Ftotal β=28.435, P<0.05). The highest radioactivity levels is in groundwater, followed by river water, and the lowest is in lake and reservoir water. Conclusions The natural radioactivity background levels in drinking raw water in Guangdong province is lower than the limit value on drinking water stipulated by our country. The radioactivity levels in raw water in western Guangdong is significantly higher than in other water systems, and the radioactivity level in river water is also significantly higher than in lake and reservoir water. Key words: Radioactive level; Raw water; Gross αradioactivity; Gross βradioactivity

ABSTRACTNainital district is naturally gifted with numbers of natural water bodies. Among these water bodies, the four lakes (Nainital, Bhimtal, Naukuchiatal and Sattal) are the major source of freshwater for the local inhabitants and industries situated in surrounding area. However, the lakes receive an enormous amount of untreated wastewater which imbalances the nutrients concentration in lake water. Therefore, the present study is focused to assess the water quality using water quality indices (NSFWQI, CPI and HPI) based on the concentration of parameters (like DO, BOD, heavy metals, etc.) in the lakes. The envirometric applications (HCA and PCA) were also used to identify the similarity in pollution load at sampling locations and the source of factor responsible for pollution in the lakes. The water samples were collected in pre- and post-monsoon months in the year 2014–2015, from 12 sampling locations. The results indicate that the water quality of lakes is unsuitable for drinking, as the average CPI was 0.90 and 0.88 in Bhimtal Lake, 1.42 and 1.43 in Nainital Lake, 1.19 and 1.27 in Naukuchiatal Lake, 1.46 and 1.42 in Sattal Lake in pre- and post-monsoon months, respectively. The HPI was found more in Nainital Lake than in rest other three lakes, while risk assessment index (RAI) was found in range RAI > 1 in the four lakes. HCA gained two clusters and PCA gained two PCs, which indicate the impact of both anthropogenic and natural sources for deterioration of water quality. Therefore, it has been suggested that the lake water must be treated before used for drinking.

The pollution of water bodies has deteriorated the quality of freshwater and the health of the natural ecosystem. In the present study, the water quality index (WQI) was used to evaluate the spatial and temporal contamination levels in Lake Yuriria, Guanajuato, Mexico. Water quality was monitored at 27 different locations (monitoring points) in the dry season (April) and after the rainy season (November), measuring 21 physicochemical water parameters, 2 biological parameters, and 19 metal concentrations. The data analysis revealed that Yuriria Lake is a eutrophic water body. Six monitoring points exhibited a poor WQI (25–50) in April, and seven monitoring sites were classified as having poor water quality in November. The remaining monitoring points showed a WQI categorized as fair (51–70) in both periods. The present study analyzes an extensive distribution of monitoring points over the lake’s surface in two periods, showing a significant spatial and temporal representation of water quality. In addition, the major pollution sources identified include agricultural runoff and effluents from a nearby waterway and freshwater river. Finally, the key physicochemical parameters that determined the water quality were identified. BOD5, NH4+, P, orthophosphates, DO, conductivity, TSS, and color were linked to anthropogenic pollution sources, and Li, Ni, Zn, Cd, Ba, and Pb concentrations were linked to natural contamination sources. This study demonstrates the utility and versatility of these methodologies in water quality research, and it is the first spatial and temporal WQI analysis of Yuriria Lake.

Previous investigations on Sicilian man made lakes suggested that physical factors, along with the specific morphology and hydrology of the water body, are important in selecting phytoplankton species. In particular, the variations of the zmix/zeu ratio due to the operational procedure to which reservoirs are generally subject were recognised as a trigger allowing the assemblage shift. To investigate if these variations may be considered analogous to those occurring in natural lakes as trophic state and phytoplankton biomass increase, causing a transparency decrease and a contraction of the euphotic depth, phytoplankton were collected in two natural water bodies, one mesotrophic (Lake Biviere di Cesaro) the other eutrophic (Lake Soprano), and compared with those collected in two reservoirs with analogous trophic characteristics (Lake Rosamarina, mesotrophic and Lake Arancio, eutrophic). Particular attention was paid to the dynamics of two key groups: Cyanophytes and chlorophytes. In all four water bodies, transparency mainly depended on chlorophyll level. Annual average value of phytoplankton biomass in the mesotrophic environments was below 2.0 mg l−1, whereas in the eutrophic systems it was well above 10 mg l−1. All water bodies showed the presence of cyanophytes (e.g. Anabaena spp., Anabaenopsis spp., Microcystis spp., Planktothrix spp.) and chlorophytes (e.g. Chlamydomonas spp., Botryococcus spp., Oocystis spp., Scenedesmus spp., Pediastrum spp.), but their relative proportions and body size dimensions were different. In particular, small colonial chlorophytes and large-colony forming cyanophytes were most common in the most eutrophic water bodies, whereas larger colonies of green algae in those with a lower trophic state. The results showed that, under the same climatic conditions, autogenic (increase of biomass, decrease in light penetration and euphotic depth) and allogenic (use of the stored waters, anticipated breaking of the thermocline, increase of the mixing depth) processes may shift the structure of phytoplankton assemblage in the same direction even though the quantity of biomass remains linked to nutrient availability.

An effluent receiving stream and Opa River to which it drains within Obafemi Awolowo University, South-Western Nigeria, were studied to ascertain the level of physico-chemical and biological pollution. Water samples were collected and analysed using various standard methods for planktonic abundance and selected physico-chemical parameters over a period of seven months. Most of the water quality parameters investigated showed statistically insignificant differences between the stream and Opa River, except of conductivity, nitrate and turbidity. Notable parameters were nutrient level indicator parameters (conductivity, nitrate, organic matter, COD and planktonic abundance) whose mean concentrations were higher in the effluent receiving stream than in Opa River. Even more, the seasonal variations of some of the investigated parameters (sulphate, organic matter and conductivity) at both sampled stations revealed the effect of anthropogenic run-off as additional source of dissolved nutrient and chemical enrichment rather than the effluent only. Highest occurrence of Chlorophyceae and abundance of Bacillariophyceae in the studied water bodies revealed a level of organic pollution, while the low occurrence species diversity of copepod, cladocera, diptera and protozoa further connotes the unfavourable physico-chemical condition of the water bodies. However, this effect was observed to be reduced at the point where the stream emptied into Opa River. Hence, the effect of the effluent discharge may not pose a health risk to several rural communities downstream which rely on the receiving water body primarily as their source of domestic water. Nevertheless, due to the level of organic pollution recorded, it could be suggested that the oxidation pond effluent discharge should be treated and/or recycled before discharge into this natural body of water.

Under the urbanization conditions there is an increase in the technogenic impact on water bodies, which is most clearly manifested in water bodies located on the territory of residential development. The value of reservoirs in cities lies in the possibility of using them as recreation places. Pollutants enter such water bodies with organized wastewater from industrial production and urban storm water. However, in a significant part of urban areas, the system of surface runoff is not organized. In this case, rain and snowmelt runoff enters water bodies disorderly (diffusely). Pollutants decrease the quality of natural waters, disrupt the functioning of aquatic ecosystems and reduce the self-purification ability. As a result, there is an intensification of the processes of eutrophication of water bodies, swamping and disturbance of local biocenoses. Pollutants entering surface water bodies accumulate in bottom sediments and create secondary pollution of rivers. Bottom sediments of reservoirs are accumulators of heavy metals. Due to sorption processes, water is purified from heavy metals, but under certain conditions the desorption of metals and their transition, when in the dissolved state, into the water column are observed, thus, secondary pollution occurs. In this study, the influence of the state of the catchment area on water quality in a reservoir, the content of pollutants in water and bottom sediments have been investigated. It is shown that the quality of water and bottom sediments in terms of content of chemical elements is determined by the type of anthropogenic load. For the river sections, not subject to technogenic load, the main influence is the state of the atmosphere and catchment area, from which the diffuse flow of rain and melt water occurs. The composition of heavy metals in water and bottom sediments mainly characterizes the natural geochemical background. The discharge of industrial wastewater leads to an increase of elements of anthropogenic origin in the composition of water and bottom sediments.

Best management practices (BMPs) are the tools which are adopted to run any activity while inflicting least negative impacts on the surrounding environment. Since, water pollution is one of the most important issues in today's world; it is indispensable to discuss the activities which are deteriorating its quality. Although, a number of treatment technologies and methods are in place for treating the point sources of pollution, there is a need to address nonpoint sources of pollution. There are many successful practices which are capable of curtailing the impacts of nonpoint source pollution, if adopted. In this paper an attempt has been made to evaluate the performance and trade‐offs of various management practices to address the issues of agricultural nonpoint source pollution. Nevertheless, there is a dearth of guiding principles which can pave a way for adoption of these practices. Therefore, an attempt has also been made to explore the aspects of policy formulations along with emphasizing the factors which can lead to adoption/ non‐adoption of such practices.

Water quality evolution modeling is very important to predict the changes in surface water quality for water resources and environmental management in the world. Worldwide, in the last decades, hundreds of surface water quality models have been developed. Water quality models based on advanced hydroinformatic tools are an efficient way to simulate and predict the pollutant transport in water courses, lakes and reservoirs, which can contribute to saving the cost of labors and materials for a large number of sampling and chemical experiments to determine the degree of pollution of water bodies. Surface water quality models are useful tools to simulate and predict the levels, distributions, and risks of chemical pollutants in a given water body, in different scenarios of pollution (point source, distributed source and accidentally pollution). The modeling results from these models are very important components of environmental impact assessment and can provide a basis and a technique support for specialists from the water resources and environmental management authorities to make the right decisions. For the case study, we use MIKE11 advanced hydroinformatic tool. MIKE11, part of the DHI software products, is a professional engineering software package for the simulation of flows, water quality and sediment transport in estuaries, rivers, irrigation systems, channels and other water bodies. MIKE11 is a user-friendly, fully dynamic, one-dimensional modeling tool for the detailed analysis, design, management and operation of both simple and complex river and channel systems. The used modules for modeling are Hydrodynamic Module and ECOLab module. The case study was realized on Bega channel sector (city of Timisoara – state border with Serbia), Timis county, Romania.

Access to safe drinking water and improved sanitation are important fundamental rights of people around the world to maintain good health. However, freshwater resources are threatened by many anthropogenic activities. Therefore, sustainable water supply is a challenge. Limited access to safe drinking water and unimproved sanitation facilities in some of its urban and rural areas are two of the major challenges for Bhutan in the 21st century. The water quality in the natural water systems in the cities and suburbs has significantly decreased while the urban infrastructure is being improved in Bhutan. Therefore, this study presents the state-of-the-art of water resources in Bhutan and the challenges for a sustainable water supply system. The current water status, drinking water sources and accessibility, factors affecting water quality degradation in urban and rural areas, water treatment methods, and implementation of sustainable drinking water accessibility with population growth in Bhutan are discussed in detail. Results of the review revealed that the water quality has deteriorated over the last decade and has a high challenge to provide safe water to some of the areas in Bhutan. Geographic changes, financial difficulties, urban expansion, and climate change are the reasons for the lack of safe drinking water accessibility for people in town areas. It is, therefore, recommended to have a comprehensive integrate water resources management (IWRM) approach while considering all stakeholders to find sustainable solutions for the challenges showcased in this paper.