Deterioration Of Surface Water Quality Research Articles

Effects of agriculture and urbanization on the geochemistry of the Scioto River, Ohio

Despite efforts to reduce nonpoint source contamination of water resources, agriculture and urbanization remain primary sources that impair surface water quality. The Scioto River in Ohio, USA has headwaters in land dominated by primarily row-crop agriculture, then flows through metropolitan Columbus, the 14th largest city in the U.S. The river serves as a major drinking water source for the city and is dammed to form two reservoirs. The Scioto River was sampled for major ions, nutrients, and select trace elements weekly to monthly at five locations along changing agricultural and urban land use. Dissolved concentrations of many analytes were highest at the most upstream agricultural location, decreased to downtown Columbus, and increased at the location furthest downstream in agricultural land. The same trend was observed in discharge-weighted yields. Because much of the study area is underlain by carbonate bedrock, correlations with Ca2+ were likely to indicate a primarily geogenic source of the solute. Elements with moderate to strong positive correlations with Ca2+ included SO42−, Ni2+, Rb+, Mo6+, and Ba2+. Inorganic N species, emanating primarily from an agricultural source, had negative relationships with Ca2+. Concentration-discharge relationships revealed chemostatic to weak dilution of analytes positively correlated with Ca2+, suggesting a geogenic source of these elements that was weakly diluted with increasing discharge. Cu2+ showed a positive concentration-discharge slope, suggesting an anthropogenic input, but a defined source was not identified. Dams on the Scioto River that form drinking water reservoirs dampened chemical correlations and concentration-discharge relationships. Both agricultural and urban sources influence the river's chemistry based on hydroclimatic conditions and land use. Higher frequency sampling of the Scioto River during high flows allowed for a more nuanced understanding of sources of solutes to the river compared to previous work. Continued water quality monitoring is imperative to maintain and protect water quality resources, especially as urban populations are predicted to grow significantly in the next century.

Machine learning approach for ion imprinted (IIP) and non-imprinted (NIP) polymer discrimination based on pyrolysis kinetic data

The improper disposal of effluents containing toxic elements, such as nickel and mercury, can result in the gradual deterioration of surface water quality, impacting aquatic ecosystems and human health. Ionically imprinted polymers (IIPs) are promising candidates for remediating toxic areas due to their high removal rates and selectivity. In this study, multifunctional IIPs were developed using Ni2+ and Hg2+ as template ions and dithizone, methacrylic acid, and ethylene glycol dimethacrylate as complexing agent, monomer, and cross-linking agent, respectively, to remove Ni (II) and Hg (II) from effluents. The thermal decomposition behavior and degradation mechanism of ion imprinted polymers were investigated to address the issue of limited lifespan. The kinetic study revealed that the samples showed significant thermal stability, and the IIP-Duo sample exhibited higher activation energy compared to the non-imprinted polymer (NIP) and the mono-imprinted polymer (IIP), indicating that double impression alters the structure of the polymer and consequently its thermal degradation. Three machine learning models were applied to classify the samples according to imprinting, successfully predicting 95% or more of the classes correctly without overfitting or overmodelling. The master plot method showed that imprinting did not affect the thermal decomposition pathway, with the IIP, IIP-Duo, and NIP samples presenting the same mechanism geometrical contraction model (R3) at a conversion rate between 0.4 and 0.9. These findings suggest that multifunctional IIPs are promising materials for remediating areas impacted by toxic elements.

GIS-BASED LANDSCAPE MANAGEMENT OF THE UZH RIVER BASIN: A STRATEGY TO ENHANCE RIVER WATER QUALITY

The article includes the findings of a study on the Uzh River basin’s surface water’s quality. This region is extremely important because a fraction of it is radioactively contaminated because of the Chornobyl nuclear power plant accident. Considering this, the goal of this work was to conduct a geo-informational analysis of the state and structure of the landscapes of the Uzh River basin, to identify the surface water quality parameters of this region, and to identify potential correlations between these parameters. For this purpose, we spatially divided the territory of the basin into separate massifs, in each of which, using the method of automatic decoding, we determined the ratio of the structural components of landscapes, their disturbance by erosion processes, and compared them with ground data on the quality of surface water of the massifs. According to the salt composition, all the investigated massifs have good quality conditions. The Uzh River and its tributaries should be categorized as 4 (slightly polluted) based on the average values of the trophosaprobological state, but the extreme values in some places shifted to 5 (moderately polluted). Most of the listed toxic substances were present at average levels and, for the most part, did not exceed the permitted concentrations for category 4-slightly polluted. Extreme concentrations frequently reached category 6 (polluted), which was primarily brought on by anthropogenic activity and the buildup of radioactive materials. It was found that the degree of erosive landscape destruction and the degree of landscape stabilization significantly influence the value of the integrated water quality index. Since the collected data, a three-dimensional model was developed, allowing for accurate evaluations and projections of changes in the quality of surface water based on the structural characteristics of the land shafts. Considering that some of these territories are currently in the zone of radioactive contamination, the planning of changes in the landscape structure should be coordinated with the potential risks of surface water quality deterioration, and the model proposed in this article will have significant applied value in addressing this issue.

Dynamics of land cover changes and condition of soil and surface water quality in a Mining–Altered landscape, Ghana

This study investigated the dynamics of mining effects on land use land cover changes and the chemical and physical characteristics of soil and surface water in the Ahafo mining area in Ghana. Landsat imagery was used to analyze land use-land cover changes (LULC) using a supervised classification technique. Soil samples were collected within 600 m from active mining operations and at depths of up to 75 cm, as well as surface water samples from upstream and downstream of the mine. Atomic Absorption Spectrometry was used to determine the concentration of heavy metals in the soil and water samples. The results demonstrated a significant loss of forest and other vegetation covers, which decreased from 44% to 31% to 8% and 20%, respectively, with corresponding increases in the mining site, mine water, settlement/bare surface, cropland and plantation. Organic matter, organic carbon, exchangeable bases, cation exchange capacity, available phosphorus, and pH were all moderate in the soil surrounding the mine. Except for As (4.027 mg/kg) and Hg (1 mg/kg), all heavy metals found in the soil were within FAO/WHO guidelines. Total Dissolved Solids (TDS) (416.18 mg/L), Total Suspended Solids (55.08 mg/L), Turbidity (54.49 NTU), Ca (84.49 mg/L), Mg (31.97 mg/L), nitrate (10.23 mg/L), and sulphate (606.83 mg/L) in the downstream water were higher than those in the upstream and USEPA/WHO limits for drinking water except for TDS. Because of the geology of the area, there were high concentrations of iron, manganese, and aluminum in the surface water. The results show that mining induced severe land cover changes and impaired surface water and soil quality in the mine's vicinity. The findings have implications for stakeholder education, appropriate community water interventions, and company-community-regulator participatory monitoring to avoid health risk exposure and further water and soil quality and vegetation degradation.

Land Use Land Cover (LULC) and Surface Water Quality Assessment in and around Selected Dams of Jharkhand using Water Quality Index (WQI) and Geographic Information System (GIS)

Abstract Surface water quality deterioration is mainly occurring due to anthropogenic activities at an alarming rate in developing countries. Jharkhand has been undergoing exponential urbanisation and mining, causing immense surface water pollution and water stress. The state is heavily dependent on artificial dams for its daily water supply demands. Therefore, an effort is made to monitor and ascertain the surface water quality and the influence of nearby land use pattern on water quality, in the selected five dams, namely, Hatia dam, Kanke dam, Getalsud dam, Galudih barrage, and Chandil dam are done. These dams are built on the Subarnarekha river basin, located in the Jharkhand state on a seasonal basis and associated land use land cover (LULC) changes, changes in vegetation cover using normalised difference vegetation index (NDVI) and water body changes using normalised difference water index (NDWI) that have occurred in a 5-year gap i.e. 2016 and 2021. The secondary data for the year 2016 was obtained from the Jharkhand pollution control board report published by the government of Jharkhand, India. For the year 2021, the samples were collected from sampling sites for pre, post and monsoon seasons. The chemical analysis of collected water samples was done in the laboratory for parameters like pH, dissolved oxygen, biological oxygen demand, total calcium and magnesium, hardness, total dissolved and suspended solids, alkalinity, chlorine etc. and compared with the standard values prescribed by world health organisation (WHO) and Indian standards (IS) 10500:2012. The seasonal water quality status was analysed using the water quality index (WQI) for the pre, post and monsoon seasons of 2016 and 2021. Then, the use of supervised classification method for land use land cover (LULC), normalised difference vegetation index (NDVI) and normalised difference water index (NDWI) was opted to understand the relation between the change in water quality and quantity concerning its land use and land cover, by comparison of results from the year 2016 to 2021. LULC were found using the supervised maximum likelihood classification method in ArcGIS and its accuracy was checked using the kappa accuracy method, which was found to be varying from 87 to 95% for all sites. The results showed that the overall water quality varied from good to poor indicating that it can be used for human activities but may need pre-treatment before drinking. NDWI showed a massive increase in severe drought areas for Hatia, Kanke, Chandil and Galudih barrage, whereas moderate drought regions increased for Hatia, Getalsud, and Kanke. NDVI showed dense and moderate vegetation both decreased massively for all the dam sites indicating an alarming situation and the need to adopt better land management practices.

The longevity of cultivation in decreasing the potential for phosphorus loss in runoff

Phosphorus (P) loss from highly fertilised grazed pastures can impair surface water quality. High P concentrations in grazed pastures are maintained to boost legume production, but systems that use monocultures of grass and clover can be more profitable and decrease P losses by lowering soil P in grassed areas. In contrast with using a direct drill to establish new pastures, conventional cultivation can lower topsoil P quickly and can be used as part of a farm re-grassing programme every six years. We tested if the potential for low P losses (measured by water extractable P; WEP) could be maintained over six years in pastures (ryegrass and white clover monocultures and a ryegrass and clover mixed sward) despite being fertilised (10, 35 and 100 kg P ha-1) and grazed. Cultivation (0–20 cm) decreased WEP and Olsen P in all three pastures and P rates by 30–50 % compared to direct drill and maintained this decrease for six years. A threshold in Olsen P (22 mg L-1) was noted where WEP concentrations increased at a greater rate relative to Olsen P than below. This threshold was like the critical point in Olsen P for 97 % relative yield in the pastures (22–28 mg L-1) and could be used to advise on cultivation and P fertiliser strategies to help avoid the potential for P loss without significantly compromising yield. The data indicated that cultivation could be used to quickly establish and maintain lower soil P concentrations as part of a strategy to decrease P losses and improve profit by using a split grass-clover system.

Identification of pollutant sources and evaluation of water quality improvement alternatives of a large river.

While pollutants are the most important factors for the deterioration of surface water quality, the identification of major pollutant sources for rivers is challenging, especially in areas with diverse land covers and multiple pollutant inputs. This study aims to identify the significant pollutant sources from the tributaries that are affecting the water quality and identify the limiting nutrient for algal growth in the Geum river to provide a management alternative for an improvement of the water quality. The positive matrix factorization (PMF) was applied for pollutant source identification and apportionment of the two major tributaries, Gab-cheon and Miho-cheon. Positive matrix factorization identifies three and two major pollutant sources for Gab-cheon and Miho-cheon, respectively. For Gab-cheon, wastewater treatment plants, urban, and agricultural pollution are identified as major pollutant sources. Furthermore, for Miho-cheon, agricultural and urban pollution were identified as major pollutant sources. Total phosphorus (TP) is also identified as a limiting nutrient for algal growth in the Geum river. Water quality control scenarios were formulated and improvement of water quality in the river locations was simulated and analyzed with the Environmental Fluid Dynamic Code (EFDC). Scenario results were evaluated using a water quality index. The reduction of total phosphorus (TP) from the tributaries has greatly improved the water quality, especially algal bloom in the downstream stations.

Quantitative identification of nitrate and sulfate sources of a multiple land-use area impacted by mine drainage

The rapid increase in urbanization and intensive coal mining activities have accelerated the deterioration of surface water quality. Environmental problems caused by the accumulation of nitrate and sulfate from natural, urban, and agricultural sources have attracted extensive attention. Information on nitrate and sulfate sources and their transformations is crucial for understanding the nitrogen and sulfur cycles in surface water. In this study, we monitored nitrate and sulfate in three representative rivers in mining cities in northern China. The main pollution sources and biogeochemical processes were identified by using stable isotopes (δD, δ18OH2O, δ15N, δ18ONO3, δ34S and δ18OSO4) and hydrochemistry. The contribution of natural and anthropogenic sources was quantitatively estimated based on a Bayesian mixed model. The results indicated a large variation in sulfate and nitrate sources between the different rivers. Nitrate in the Tuohe River mainly derived from manure/sewage (57.9%) and soil N (26.9%), while sulfate mainly derived from manure/sewage (41.7%) and evaporite dissolution (26.8%). For the Suihe River, nitrate was primarily sourced from chemical fertilizer (37.9%) and soil nitrogen (34.8%), while sulfate was mainly sourced from manure/sewage (33.1%) and chemical fertilizer (21.4%). For the Huihe River, nitrate mainly derived from mine drainage (56.6%) and manure/sewage (30.6%), while sulfate predominantly originated from mine drainage (58.3%) and evaporite dissolution (12.9%). Microbial nitrification was the major pathway for the migration and transformation of nitrate in the surface water. However, denitrification and bacterial sulfate reduction (BSR) did not play a significant role as aerobic conditions prevailed. In this study, we elucidated the sources and transformation mechanisms of nitrate and sulfate. Additionally, we provided a reference for formulating a comprehensive strategy for effective management and remediation of surface water contaminated with nitrate and sulfate in mining cities.

Assessing the influence of treated effluent on nutrient enrichment of surface waters using water quality indices and source apportionment

Abstract Discharges from wastewater treatment plants have been cited as one of the point sources contributing to surface water quality deterioration. However, does high-quality effluent affect water quality, and contribute significantly to nutrient enrichment or the eutrophication of receiving waters? The Vltava River and a wastewater treatment plant in the Czech Republic were used in a case study, to try to answer these questions through water quality indices and source identification. Samples were collected upstream and downstream of the effluent discharge point, and analyzed for temperature, pH, dissolved oxygen, chemical oxygen demand, nitrate, nitrite, ammonium, phosphate and sulfate. No statistically significant difference (P > 0.05) was observed between most of the upstream and downstream samples’ physicochemical characteristics. The water quality, organic pollution and eutrophication indices of the river, upstream of the effluent discharge point were 83.48, 2.05 and 2.67, respectively, but increased to 99.06, 2.87 and 3.74 downstream. Nutrient source identification using principal component analysis suggests that the increase might be due to the effluent discharge. However, the river's comprehensive ecological (quality classification) status was the same upstream as downstream, indicating that the discharged effluent did not cause nutrient enrichment of the river.

Combining hydrochemistry and hydrogen and oxygen stable isotopes to reveal the influence of human activities on surface water quality in Chaohu Lake Basin

The input of pollutants caused by human activities induces the deterioration of surface water quality. To reveal the characteristics of surface water quality in Chaohu Lake Basin and the influence of human activities, the hydrochemistry and stable isotope composition of hydrogen and oxygen in lake water and inflow river water were analyzed. The results show that the hydrochemical type of lake water is the Na–Cl type,while river water is the Na–Cl, Ca–Cl and mixed types. The ion proportional coefficient method and principal component analysis show that surface water is controlled by weathering of evaporated salt rocks and silicate rocks, in which Cl- and SO42- are affected by fertilizers and sewage to some extent. There is a strong correlation between conventional ions and nutrient indexes, which indicates that dissolved ions are affected not only by rock weathering but also by human activities (such as the discharge of domestic sewage or nitrogen-containing wastewater and the use of fertilizers). The stable isotope values of hydrogen and oxygen in surface water are distributed at the lower right portion of the local precipitation line and are close to it, indicating that surface water mainly originates from precipitation. The high value of d-excess values in surface water indicates that evaporation is weak. As pollution indicators, EC, Cl- and NO3- indicates that the Nanfei River, Dianbu River, Shiwuli River and Pai River flow in northwestern of Chaohu Lake Basin through Hefei urban city are severely polluted, NO3- originates from manure and sewage. Rivers flowing through farmland areas are less polluted, and the use of agricultural fertilizer contributes greatly to NO3-.

Identification of multilevel priority management areas for diffuse pollutants based on streamflow continuity in a water-deficient watershed

Agricultural diffuse pollution is, on the global scale, one of the most important causes of surface water quality deterioration and eutrophication. However, the identification of agricultural priority management areas (APMAs) for diffuse pollutants is still an ongoing challenge in water-deficient watersheds. To enhance the accuracy of identification of APMA, a modified framework for APMA identification is proposed by combining the streamflow continuity index constructed by Reliability-Resilience-Vulnerability (R-R-V) indices and the SWAT model in this paper. This novel framework was tested in Zhang River Watershed and the main results are as follows. First, the SWAT model is calibrated and validated with a good performance of the Nash-Sutcliffe efficiency (NSE) and coefficient of determination (R2)greater than 0.75 and 0.80 for both the calibration and validation periods, respectively. Second, the wet year is found to be the critical period for diffuse TN and TP output at an annual scale. Specifically, the critical loss period of TN is identified as from April to October on the monthly scale, especially in July and August. However, the critical period of TP loss is mainly concentrated in the range from July to September in Zhang River Watershed. Third, the reaches with a high streamflow continuity index(SCI) are primarily located in mid-downstream part of the watershed. The reaches are mostly characterized by relatively low SCI values due to the lack of streamflow volume in the upper reaches. Fourth, the APMAs for TN and TP for the watershed final outlet connected to the Yuecheng Reservoir are approximately distributed in two areas by considering the SCI estimation, namely the Qingzhang River sub-watershed and the mid-downstream part of the Zhuozhang River sub-watershed. Compared with the results obtained from the modified APMA framework, the main areas of TN and TP APMAs may be overestimated by 27.17 and 10.02 percentage points, respectively, using the original APMAs framework without the SCI evaluation. This revised APMA framework can be easily extended to other water-deficient watersheds for improving the efficacy of the identification and the control of agricultural diffuse pollution.

Assessing the factors influencing water quality using environment water quality index and partial least squares structural equation model in the Ebinur Lake Watershed, Xinjiang, China.

Surface water quality deterioration is commonly associated with environmental changes and human activities. Although some research has been carried out to evaluate the relationship between various influencing factors and water quality, there is still very little scientific understanding on how to accurately define the key factors of water quality deterioration. This study aims to quantify the impact of environmental factors and land use land cover (LULC) changes on water quality in the Ebinur Lake Watershed, Xinjiang, China. A total of 20 water parameters were used to calculate the Environment Water Quality Index (CWQI). Meanwhile, the partial least squares-structural equation model (PLS-SEM) was used to quantify the impact of eleven factors influencing water quality in the watershed. About 33.3% of the monitoring points that located mostly in the downstream region with dominant anthropogenic activities were detected as poor quality. There were no obvious temporal changes in water quality from 2016 to 2019. The PLS-SEM simulation shows that the latent variable "land use/cover types" (path coefficient = - 0.600) and "Environmental factor" (path coefficient = - 0.313) are two major factors affected water quality in the Ebinur Lake Watershed, with a strong explanatory power to water quality change (R2 = 0.727). In the latent variable "Environmental factors", the "NDVI" and "night light brightness value" have a great influence on water quality, with the weights of 0.451 and 0.427, respectively. Correspondingly, the "farmland" and "forest land" within the latent variable of "Land use/cover type" have a considerable impact water quality, with the weights of 0.361 and - 0.340, respectively. In conclusion, the influence of anthropogenic activities on surface water quality of the Ebinur Lake Watershed is greater than that of environmental factors. Compared with the traditional multivariate statistical method, PLS-SEM provides a new insight for quantifying the complex relationship between different influencing factors and water quality.

Management of groundwater resources in transboundary territories (on the example of the Russian Federation and the Republic of Estonia)

Groundwater, as a source of water supply, the most important mineral and geopolitical resource, , is often the only source of high-quality drinking water that is protected from pollution under conditions of increasing deterioration of surface water quality. Transboundary groundwaters are the focus of hydrogeological researchers for a number of reasons, including the reduction and pollution of water resources as a result of economic activities. The increased controversy between states over transboundary water issues has necessitated the development of international legal documents on issues related to water conflict prevention and the sustainable use of fresh water. As part of the analysis of the problem of legal regulation of groundwater extraction from transboundary aquifers and complexes, it is proposed to consider this aspect on the example of Russia. The problems of regulation of rational use and protection of fresh water in the bilateral treaties of the Russian Federation were revealed; a methodology for the management of groundwater extraction in the territory of the transboundary aquifer was developed, the size, parameters, and factors influencing the formation of the transboundary zone have been determined (based on research and analysis of water intake activities in the border areas of the Russian Federation and the Republic of Estonia) were determined.

A comprehensive evaluation of surface water quality and potential health risk assessments of Sisa river, Kumasi

Surface water quality deterioration is one of the primary issues of the twenty-first century due to the high demand for drinking and irrigation purposes in most communities. The purpose of this study was to investigate the suitability of the Sisa river in Kumasi Metropolis, as well as the critical factors affecting its water quality and human health risk among children and adults. The findings indicated that the surface water was alkaline and, in some samples, turbidity, alkalinity, color, microbial, Fe, and Cr concentrations exceeded the standard permissible limits of WHO. Water from individual sampling sites contained Escherichia coli, total, and fecal coliform counts. There was no strong significant correlation among the levels of the heavy metals, suggesting their lack of control in their distribution, source, and transport pathway. Principal component analysis (PCA) revealed three factors that account for about 98.86 % of the total variance in the surface water quality data set. Moreover, PCA findings revealed that geogenic and anthropogenic sources were responsible for variations in physicochemical and microbiological parameters of the study area. Fe and Cr were found to have high toxic levels among the heavy metals analyzed. The heavy metal assessment index indicated moderate to high hazards. Cu had a hazard index greater than one at Duase and Atonsu, indicating a possible non-carcinogenic risk. The overall carcinogenic risk values were greater than 10−6, indicating the possibility of cancer. Water quality index values ranging from 97.95 to 137.22 percent showed that about 75 % of the samples were of poor quality. Based on these results, we recommended proper water management strategies and policies should be implemented as soon as possible to manage and protect the water resources.

Urban Heat Island: Causes, Consequences, and Mitigation Measures with Emphasis on Reflective and Permeable Pavements

Economic and social development of urban and rural areas continues in parallel with the increase of the human population, especially in developing countries, which leads to sustained expansion of impervious surface areas, particularly paved surfaces. The conversion of pervious surfaces to impervious surfaces significantly modifies local energy balance in urban areas and contributes to urban heat island (UHI) formation, mainly in densely developed cities. This paper represents a literature review on the causes and consequences of the UHI and potential measures that could be adopted to improve the urban microclimate. The primary focus is to discuss and summarise significant findings on the UHI phenomenon and its consequences, such as the impact on human thermal comfort and health, energy consumption, air pollution, and surface water quality deterioration. Regarding the measures to mitigate UHI, particular emphasis is given to the reflective and permeable pavements.

Bacterial diversity and predicted enzymatic function in a multipurpose surface water system \u2013 from wastewater effluent discharges to drinking water production

BackgroundRivers and lakes are used for multiple purposes such as for drinking water (DW) production, recreation, and as recipients of wastewater from various sources. The deterioration of surface water quality with wastewater is well-known, but less is known about the bacterial community dynamics in the affected surface waters. Understanding the bacterial community characteristics —from the source of contamination, through the watershed to the DW production process—may help safeguard human health and the environment.ResultsThe spatial and seasonal dynamics of bacterial communities, their predicted functions, and potential health-related bacterial (PHRB) reads within the Kokemäenjoki River watershed in southwest Finland were analyzed with the 16S rRNA-gene amplicon sequencing method. Water samples were collected from various sampling points of the watershed, from its major pollution sources (sewage influent and effluent, industrial effluent, mine runoff) and different stages of the DW treatment process (pre-treatment, groundwater observation well, DW production well) by using the river water as raw water with an artificial groundwater recharge (AGR).The beta-diversity analysis revealed that bacterial communities were highly varied among sample groups (R = 0.92, p < 0.001, ANOSIM). The species richness and evenness indices were highest in surface water (Chao1; 920 ± 10) among sample groups and gradually decreased during the DW treatment process (DW production well; Chao1: 320 ± 20). Although the phylum Proteobacteria was omnipresent, its relative abundance was higher in sewage and industrial effluents (66–80%) than in surface water (55%). Phyla Firmicutes and Fusobacteria were only detected in sewage samples. Actinobacteria was more abundant in the surface water (≥13%) than in other groups (≤3%). Acidobacteria was more abundant in the DW treatment process (≥13%) than in others (≤2%). In total, the share of PHRB reads was higher in sewage and surface water than in the DW treatment samples. The seasonal effect in bacterial communities was observed only on surface water samples, with the lowest diversity during summer.ConclusionsThe low bacterial diversity and absence of PHRB read in the DW samples indicate AGR can produce biologically stable and microbiologically safe drinking water. Furthermore, the significantly different bacterial communities at the pollution sources compared to surface water and DW samples highlight the importance of effective wastewater treatment for protecting the environment and human health.

Impact of the 2018 drought on pharmaceutical concentrations and general water quality of the Rhine and Meuse rivers.

Hydrological droughts are expected to increase in frequency and severity due to changing climate in several river basins. Recent severe droughts, like the 2018 drought in northwestern Europe, have shown major challenges for water management, not only in terms of water quantity, but also water quality. However, these water quality impacts have received far less attention, and limited understanding exists, in particular regarding concentration responses of emerging chemicals, such as pharmaceutical in surface waters under droughts. This study therefore shows the impacts of the 2018 drought on the water quality of the Rhine and Meuse rivers (Western Europe) focusing on a selection of water quality parameters relevant to multiple sectoral water uses and ecosystem health, i.e. water temperature, salinity and four pharmaceuticals (carbamazepine, metoprolol, ibuprofen and sulfamethoxazole). Surface water quality data of six monitoring stations (mainly in the Netherlands) were analyzed for the 2018 drought in comparison to the reference period 2014-2017. Our results show that low flow combined with high temperatures resulted in a general deterioration of surface water quality of both the Meuse and Rhine rivers during the 2018 drought. This was reflected by significant increases in water temperatures (average of +1.9°C) and salinity levels (+11%). While we found higher concentrations of some pharmaceuticals (carbamazepine (+10%) and metoprolol (+29%)), these increases were statistically insignificant. The decline in water quality is primarily caused by limited dilution of the chemical load derived from point sources and salinity intrusion in the lower part of Rhine-Meuse delta. A comparison of the water quality responses of the Rhine and Meuse shows larger impacts for the rainfed Meuse river with lower summer flow, compared to the mixed rain- and snowmelt-fed Rhine river. Sustainable, transboundary river water management is essential to ensure water of suitable quality for different sectoral uses during future projected droughts.

Assessment of river water quality indices based on various fuzzy models and arithmetic indexing method

River water is a major source of natural freshwater for both rural and urban areas. The severe threat in the form of pollutants is the major cause of deterioration of surface water quality. Water Quality Index (WQI) is a single measure of overall water quality in a specific location with a special emphasis on the time-based readings of water quality parameters. WQI can be used as a good tool to assess the intensity of water pollution. In this study, two water quality index models using fuzzy logic in MATLAB R2015a by trapezoidal and sigmoid membership functions are proposed. Fuzzy water quality index models were developed for various seasons, using eight experimentally estimated water quality parameters, such as Temperature (T), Chlorides (Cal−), Nitrates (NO3 −), Sulphates (SO4 −), Total Coli forms (TC), Total Dissolved Solids(TDS), Electrical conductivity (EC) and Total Hardness (TH) of the water samples at 8 locations stretching55 km of Chalakudy River from January 2018 to December 2018. The models are validated by comparing with the WQI values obtained by the application of arithmetic index method (AIM) based on Indian Standards, by finding the absolute average relative error (AARE) and root mean square error (RMSE). The fuzzy logic model using trapezoidal membership function (FTWQI) was found to be more reliable with the least error (AARE 0.0214 and RMSE 0.318) compared with the fFuzzy sigmoid water quality index (FSWQI) (AARE 0.573 and RMSE 0.86). The models enable the easy prediction of the risk of water consumption.

Assessment of groundwater quality and determination of hydrochemical evolution of groundwater in Shillong, Meghalaya (India)

Deterioration of surface water quality in various parts of India due to increasing urbanization has led to the extensive usage of groundwater for various domestic and irrigation needs, thereby raising concerns over its quality. However, there are very few studies focussing over the issue of groundwater quality in North-Eastern region of India. In order to make an assessment of the quality of groundwater for drinking and irrigation purposes, this study was carried out in Shillong—the Capital City of Meghalaya State in North-East India during pre-monsoon and post-monsoon seasons of 2018. Standard sampling and analytical procedures were followed for groundwater quality assessment. Minimal variation was observed in the water quality of pre- and post-monsoon seasons. However, the study found that groundwater samples are having acidic pH and presence of nitrate is also reported. Some of the samples also showed the presence of mercury, nickel, and cadmium. The presence of these contaminants could be attributed to the industrial activities in the state. Overall, the groundwater quality was found suitable for drinking and irrigation purposes after conventional treatment. Hydrochemical studies further inferred that groundwater properties in the region are influenced by the rock weathering along with the atmospheric precipitation.

Amending soils of different pH to decrease phosphorus losses

Context Soils irrigated with wastewater are generally phosphorus (P)-enriched. P losses from these soils may impair surface water quality. However, wastewater applications also alter soil pH and P availability. Aims We investigated if amending soils with aluminium (Al), iron (Fe) or calcium (Ca) sorbents could decrease the potential for P losses despite altering soil pH and potentially increasing soil P availability. Methods Seven soils (pH 5.3–6.9) were incubated with lime, gypsum, hydrotalcite, alum sulfate, ferric sulfate, and ferric chloride at rates of 0:1, 0.25:1, 0.5:1 and 1:1 molar ratios of Al/Fe to P, and 0:1, 0.5:1, 1:1 and 5:3 for Ca to P, respectively. After 21 days pH and water extractable P (WEP) were measured. Key results In most cases the application of Al, Fe and Ca amendments decreased WEP in proportion to the rates applied. However, poor performance was noted when amendments were mismatched to soils altering their pH into the range where high soil P availability was expected. Of the amendments used, alum and iron sulfate were the most cost-efficient. However, even when optimised and applied to critical source areas the estimated cost-effectiveness of these amendments is still poor and may only be effective in the short term. Conclusions and implications We therefore recommend that other strategies such as inversion tillage bringing low P topsoil to the surface (and decreasing the potential for P loss by surface runoff) together with changes in the farm system to extract more P from the topsoil are the only strategies that will decrease the potential for P loss cost-effectively and in the long-term.