Nitrate Levels In Water Research Articles

Investigations on the removal of phosphate and nitrate using a mixture of cactus and Moringa seed powder via RSM techniques

Humans utilize water for a variety of purposes, which needs the treatment. The study explores the use of blended cactus and Moringa seed powder as coagulants to reduce phosphate and nitrate levels in surface water. Samples was collected from the Kitto River in the Oromiya region, Jimma, Ethiopia, were analyzed using various tools. A jar test was used to investigate the study using blended powder of cactus and Moringa under different operating parameters. In this study, pH (5−9), settling time (30–50 min), stirring speed (40–50 rpm), and dosage ratio (50 %C to 50 %M, 25 % C to 75 %M, and 75 % C to 25 % M) were used to analyze the removal % of NO3-, and PO43-. The highest removal efficiency was achieved with a dosage ratio of 3 (75 % M: 25 % C), a pH of 7, a settling time between 40 to 50 min, and a stirring speed of less than 50 rpm. The removal efficiencies closely matched the predicted values (92.6 %, 88.31 %) and actual values (99.46 %, 92.32 %) for PO43- and NO3- respectively. Hence, the finding showed that blended cactus with Moringa seed increases the effectiveness of phosphate and nitrate reduction.

The Effectiveness of Moringa Oleifera Seed Powder and Mixing Time (Fast-Low Speed) Using Jartest in Reducing Nitrate Levels in River Water

Background:Moringa oleiferais a fast-growing, long-lived plant that blooms throughout the year and can withstand extreme arid conditions. Objective:This study aims to examine the effectiveness of Moringa oleiferaseed powder in reducing nitrate levels in river water. Method:The research method employed in this study involved analysis using the Paired Sample Statistical Test. Result:The statistical test results revealed a significance value of 0.017 (p < 0.05) and a mixing time variation significance of 0.011 (p < 0.05). These values indicate that the null hypothesis (H0: there is no relationship between the independent and dependent variables) is rejected, while the alternative hypothesis (Ha: there is a relationship between the independent and dependent variables) is accepted. This implies a significant difference in the reduction of nitrate levels between the pretest and posttest data, demonstrating that the use of Moringaseed powder is effective in reducing nitrate levels. Conclusion:This study concludes that the administration of Moringaseed powder at a dose of 400 mg/L, with a mixing time of 2 minutes at a fast speed (80 rpm) and 20 minutes at a low speed (40 rpm), is most effective in significantly reducing nitrate levels in river water. Keywords:Moringa oleifera; nitrate levels; river water; Indonesia

Tracing pesticide dynamics: High resolution offers new insights to karst groundwater quality

Generally, karst aquifers and springs are highly susceptible to contamination due to the high permeability and, therefore, groundwater flow velocities. The often thin soil cover, accompanied by dolines, can lead to fast infiltration of precipitation water loaded with mobilized contaminants such as pesticides and their transformation products. To date, continuous, temporally highly resolved in-situ monitoring to decipher concentration dynamics for a broad range of pesticides is missing. Therefore, a transportable HPLC-HRMS/MS system (MS2field) was positioned at two karst study sites in the Swiss Jura. Water samples were collected and analyzed for pesticides and their transformation products in-situ every 20 min for 6 weeks in 2021 and 8 weeks in 2022. During the spraying season in 2021, six rain events at site 1 and three at site 2 in 2022 were captured. Concurrently, the water quality parameters electrical conductivity, pH, nitrate, turbidity, and water level, were monitored continuously at high temporal resolution. Further, bacterial cell counts were monitored via online flow cytometry.In 2021, several pesticides and pesticide transformation products were detected in peak concentrations after rain events, of which metamitron showed the highest concentration of up to 1000 ng/L. In one rain event, the Swiss federal and EU drinking water limit of 100 ng/L was exceeded for up to 38 h. Compared with highly frequent MS2field samples collected every 20 min, 42-hours composite samples severely underestimated peak concentrations for all compounds, especially for labile ones. Therefore, it was demonstrated that exceedences of the regulatory limit would have been missed if just composite sampling would have been conducted. Peak concentrations of pesticides coincided with peaks in nitrate concentration and bacterial cell counts following rain events. The correlation analysis showed strong correlations between the three analyzed contaminants (pesticides, nitrate and bacteria), and the proxy parameters electrical conductivity, and pH. The investigation of a second spring revealed similar dynamics indicating that these can be expected in other karst aquifers as well.

Impact of Droughts on Served Drinking Water Disparities in California, 2007-2020.

Objectives. To quantify the impact of droughts on drinking water arsenic and nitrate levels provided by community water systems (CWSs) in California and to assess whether this effect varies across sociodemographic subgroups. Methods. I integrated CWS characteristics, drought records, sociodemographic data, and regulatory drinking water samples (n = 83 317) from 2378 water systems serving 34.8 million residents from 2007 to 2020. I analyzed differential drought effects using fixed-effect regression analyses that cumulatively accounted for CWS-level trends, income, and agricultural measures. Results. CWSs serving majority Latino/a communities show persistently higher and more variable drinking water nitrate levels. Drought increased nitrate concentrations in majority Latino/a communities, with the effect doubling for CWSs with more than 75% Latino/a populations served. Arsenic concentrations in surface sources also increased during drought for all groups. Differential effects are driven by very small (< 500) and privately owned systems. Conclusions. Impending droughts driven by climate change may further increase drinking water disparities and arsenic threats. This underscores the critical need to address existing inequities in climate resilience planning and grant making. (Am J Public Health. 2024;114(9):935-945. https://doi.org/10.2105/AJPH.2024.307758).

Removal of nitrate and phosphate by aquatic plants during aquarium‐based ornamental fish production

AbstractObjectiveThe rising demand for ornamental fish and plants in aquariums is met through industrial production. However, higher production densities may negatively impact water quality (such as ammonia, nitrate, nitrite, and dissolved oxygen levels), thus impacting production. This can be mitigated by utilizing specific aquatic plants to promote sustainable ornamental fish production. This study aimed to determine how the water quality in ornamental fish tanks can be improved using two floating aquarium plant species: Najas grass Najas guadalupensis and Java moss Taxiphyllum barbieri.MethodsThe efficiency of nitrate and phosphate filtration by the two plant species was determined in aquariums containing Endler Guppies Poecilia wingei. The duration of the study was 4 weeks, and the water quality parameters were measured weekly. The growth rates of the two plants were measured at the beginning and end of the study period.ResultNajas grass effectively maintained lower nitrate and phosphate levels while showing robust growth. By week 4, nitrate levels in control tanks rose to 33.75 and 35.00 mg/L in the two independent experiments, while nitrate in tanks with Najas grass only reached 8.75 and 11.50 mg/L. Phosphate levels in control tanks increased to 2.42 and 2.40 mg/L compared to 1.075 and 1.05 mg/L in tanks with Najas grass. In single‐species tanks, Najas grass showed a 1.6‐fold biomass increase, while Java moss showed a 1.2‐fold increase. In tanks with both species, Najas grass biomass increased significantly, whereas Java moss biomass decreased.ConclusionThe superior competitive ability of Najas grass (allelopathy and increased nutrient uptake) underlies the findings of this study and indicates that this species is a better option for maintaining low levels of nitrate and phosphate in aquarium water. This finding can contribute to creating a cleaner and healthier environment for fish species involved in industrial ornamental fish production and trade.

Exploring alternative measurement methods and greenness metrics for nitrate levels in coconut water: android application and mid-infrared spectroscopy approaches

Exploring alternative measurement methods and greenness metrics for nitrate levels in coconut water: android application and mid-infrared spectroscopy approaches

Tracing Mine Water Flows in a Dolomite Quarry, South Africa, Using Hydrochemistry and Stable Isotopes

South Africa has a growing population, a relatively dry climate, and abundant mining activity, all of which increase the importance of water management. The Mooiplaas Dolomite Quarry, south east of Pretoria, has been mining metallurgical grade dolomite since 1969, within the productive karst aquifers of the Malmani Subgroup, Transvaal Supergroup. This study was conducted to elucidate the flow of water around the site, including the mine water and groundwater. The site was investigated by sampling precipitation, surface water, groundwater, and mine water for hydrochemical and stable isotope analysis from 2011 to 2017, totalling over 400 samples. Levels of nitrate in groundwater and mine water were marginally above drinking water limits, from explosives residues, and ammonia in the nearby Hennops River was unacceptably high due to municipal sewage outfalls, but otherwise, water quality was very good. Alkalinity from rock weathering, aided by crushing of dolomite, was the main control on water chemistry. Combined analysis of dissolved matter (TDS, nitrate, Mg, etc.) suggested that the dewatering of the mine and resultant recharge from the slimes dams caused an aerated zone of groundwater, which mixed with regional groundwater flowing beneath the site. Stable isotopes, with an evaporated signature from the mine open water bodies, also showed how mine operations cause recharge to groundwater and subsequent seepage back into the pit lakes. The mine appears not to contaminate the regional groundwater; however, mine designs should avoid situations where process water flows via groundwater back into pits, causing excessive dewatering costs.

Improved determination of nitrate isotopes in irrigated agricultural areas and Bayesian mixing model quantification of nitrate sources and fate

Technological advancements in isotope techniques have been widely utilized in environmental pollution research, particularly for the monitoring of nitrate pollution in water. The utilization of pretreatment with an aqueous nitric acid solution offers numerous advantages in analyzing isotopic composition; however, there is still room for improvement regarding conversion efficiency, reduced reaction time, and cost control. In light of this, this study proposes an enhanced chemical conversion method that involves mitigating the interference caused by the nitrogen azide reaction during the pretreatment process, optimizing the purge gas to remove interfering factors, and improving the inlet device for measuring nitrous oxide. The improved method was applied to determine nitrate isotopes in the Ulansuhai Basin, Inner Mongolia and its reliability was verified through analytical results obtained from bacterial denitrification methods. The mean δ15N-NO3- and δ18O-NO3- values determined using the chemical transformation method were 4.85‰ and 23.44‰, respectively. Compared with the previous method, the improved method enhanced the maneuverability of precise control, the pretreatment time was reduced from 2 to 3 hours to 1.5 hours, and the experimental cost was scaled down to half of the original one. In addition, the contribution of each source was calculated by combining nitrate isotopes with a Bayesian stable isotope mixing model. It was found that manure sewage accounted for (50.1±22.6) % while soil nitrogen sources contributed (25.1±20.4) % to nitrate levels in Ulansuhai Lake's water. The chemical conversion methods successfully improved within this study can also be applied to other watersheds or regions. These research findings provide a valuable theoretical foundation for managing nitrogen sources within watersheds.

Spatial and seasonal pattern of microbial nitrate reduction in coastal sediments in the Vistula River plume area, Gulf of Gdańsk

Estuaries can remove and/or retain land-derived nitrogen (N) and act as filters buffering N loads to the open sea. The N coastal filter can be seasonally variable depending on water temperature and transported loads, two factors acting in synergy and strongly influenced by climate change. The capacity of sediments to mitigate riverine N loads was investigated at four sites in the Vistula River plume area (Gulf of Gdańsk, Southern Baltic Sea). Samplings were carried out in two contrasting seasons: spring and summer, characterized by different water temperatures and nitrate (NO3-) levels. Inorganic N fluxes, and rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in intact sediment cores by means of dark incubations and 15N-nitrate concentration-series experiments. Sampling sites were selected along a gradient of depth (5 to 24 m), that was also a gradient of sediment organic matter content. In both seasons, denitrification rates increased along with depth and from spring (6.5 ± 7.0 µmol m-2 h-1) to summer (20.4 ± 15.4 µmol m-2 h-1), despite lower NO3- concentrations in summer. In spring, at higher NO3- loading, denitrification was likely limited by low water temperature, and elevated sediment oxygen penetration. Coupled denitrification-nitrification prevailed over denitrification of water column NO3- across all sites and seasons, contributing to over 80% of the total denitrification. Notably, no anammox was detected at the sampling sites. DNRA exhibited low to undetectable rates in spring, especially at the shallowest sites. However, during summer, N recycling via DNRA increased and ranged from 0.7 to 14.9 µmol m-2 h-1. The denitrification efficiency (DE), calculated as the ratio between molecular nitrogen (N2) flux and dissolved inorganic N effluxes from sediments, ranged from 0 to 37% in spring, whereas in summer DE did not exceed 16%. Despite the dominance of denitrification over DNRA, the analyzed sediments acted as weak N buffers under in situ dark conditions. However, concentration-series experiments suggested high potential denitrification capacity, exceeding 400 µmol m-2 h-1, in response to short-term, large riverine inputs of NO3-.

CO2 emission and physiological aspects of sugarcane ratoon as interactive functions of nitrogen and silicon applications

Sugarcane is the primary renewable energy source in Brazil, necessitating efficient and sustainable production practices. This study assessed the impact of nitrogen sources and their combination of silicon as foliar application on carbon dioxide (CO2) emissions and physiological characteristics of sugarcane cultivated in tropical environment. The experiment was conducted using the second sugarcane ratoon (variety CTC-04), as 2x5 factorial design, with two sources of N-fertilizer (urea and calcium ammonium nitrate - CAN, association with DMPSA − 3,4-dimetilprirazol succínico, nitrification inhibitor) and different silicon concentrations such as 0, 150, 300, 450, and 600 g ha−1. Photosynthetic leaf gas exchange, water use efficiency, pigments, CO2 emissions (ECO2), ammonium and nitrate levels in the soil were observed. The results were subjected to analysis of variance using the F test along with polynomial regression and mean comparison tests. Using urea as a source of nitrogen, there was an increase in internal CO2 concentration of the plants by 19% in relation to treatment with calcium ammonium nitrate association with DMPSA (CAN + DMPSA). Nevertheless, urea increased ECO2 emissions into the atmosphere by up to 15.3% higher compared to CAN + DMPSA application. Foliar application of Si (300 g ha−1) reduced plant transpiration rate (21%), irrespective the source of N-fertilizer utilized. Thus, it is concluded that the use of calcium ammonium nitrate associated with a nitrification inhibitor is an interesting strategy for reducing CO2 emissions, as well as Si is capable of reducing the plant’s transpiration rates, making it efficient in the use of water.

Effect of water quality on causes of calf mortality in cattle-farm-associated epidemics

Abstract. Poor-quality drinking water plays a detrimental role in the suppression of calf immunity, giving rise to an increased rate of calf mortality. The present study aims to evaluate the causes of calf mortality in beef and dairy farms in relation to drinking water quality (DWQ). A convenience sample of 132 Egyptian cattle farms suffering from emerging epidemics was surveyed by collecting drinking water samples for physicochemical and microbial analysis and using a questionnaire to record hygienic risk factors affecting calf health. Statistical analysis correlates water parameters with rates of calf diarrhea, respiratory problems, severe depression, sudden death and mortality. High percentages of water sample quality parameters, e.g. pH, total dissolved solids (TDSs), hardness, chloride, nitrate, sulfate, total colony count (TCC) and total coliform count (TCFC), are above permissible limits. Water parameters, except pH, show a significant moderate positive correlation with causes of calf mortality (ρ 0.331–0.66) in winter and summer. Each cause of calf mortality was predicted by a specific water parameter, and the water nitrate level was the highest predictor, with the highest values (β = 0.504–0.577), followed by the water TDS, sulfate and microbial levels. Weak to moderate correlation (ρ 0.151–0.367) was found between calf mortality causes and some hygienic risk factors such as operation type, calf housing, calf feeders, bedding type, water source, water pipe type, drinker lining and wheel dipping. We could conclude that DWQ greatly affects causes of calf mortality, but we cannot exclude some farm hygienic risk factors.

Effect of Substituting Soybean Meal in Oreochromis niloticus Diets with Pumpkin (Cucurbita maxima) Seed Cake on Water Quality, Growth, Antioxidant Capacity, Immunity, and Carcass Composition.

A 10-week feeding experiment was performed to determine the impacts of partial substitution of soybean meal (SB) with pumpkin seed cake (PSC) in Oreochromis niloticus diets on water quality, growth rate, antioxidant capacity, immunity, and carcass composition. One hundred and fifty tilapia fish (average weight, 11.93 ± 0.17 g) were randomly allocated to five diets. The first diet (the basal diet) contained 420 g of SB per kg of feed. The remaining four diets, namely, D1, D2, D3, and D4, had SB partially replaced by PSC at 10%, 20%, 30%, and 40%, respectively. The results revealed that D4 and D1 significantly improved dissolved oxygen levels, while water temperature, pH, total ammonia, and nitrate levels were not significantly affected. Replacing SB with PSC significantly improved specific growth performance indicators and feed conversion compared to the control, with the D4 group showing the best values. Increasing PSC levels decreased serum glucose, aspartate aminotransferase, alanine aminotransferase, cholesterol, and triglyceride levels. In contrast, the D4 group had higher globulin, albumin, total protein, and lysozyme serum levels. Moreover, fish-fed PSC had significantly increased superoxide dismutase, glutathione peroxidase, and catalase activities and significantly decreased malondialdehyde levels. Increasing PSC substitution levels in fish diets increased the ash and crude lipid contents in the bodies of the fish, while crude protein and moisture decreased. In conclusion, replacing SB with PSC in fish diets significantly enhances growth performance, feed conversion, and fish health. Moreover, the findings suggest that PSC can be a promising alternative protein source for sustainable aquaculture practices.

Association between hydrochemical parameters and microbial community structure in rivers of the Republic of Tatarstan

Microbiota plays an important role in the aquatic ecosystem, maintaining balance through its ability to utilize and synthesize various substances. Anthropogenic pollution affects the composition of the aquatic microbiota, thereby disrupting the stability of the system. In this work, a comprehensive analysis of the hydrochemical parameters of the rivers of Tatarstan was carried out together with the microbiome. This has enabled the identification of bacteria that can be used as bioindicators of pollution in aquatic ecosystems. It was found that the abundance of the cyanobacteria Synechococcaceae was reduced in samples with high organic matter content, and the abundance of Microcystaceae was increased with high levels of total phosphorus and phosphates. There is also evidence that members of the Proteobacteria phylum can be bioindicators of high nitrate levels in water.

Nitrate in Gravity Feed System (GFS) Water and Health Risk Assessment in Orang Asli Village in Rembau, Negeri Sembilan

Introduction: To determine the health risk assessment due to exposure to nitrate in Gravity Feed System (GFS) water in the Orang Asli Village of Rembau, Negeri Sembilan. Methods: This study involved 48 respondents who fulfilled the inclusion and exclusion criteria. Respondents with a filtration system installed in their houses were excluded from the study. A modified questionnaire was used to obtain the socio-demographic data. All collected water samples were analyzed using a HANNA Instruments multimeter with an attached nitrate electrode. Results: Nitrate in drinking water did not exceed the maximum limit of 45 mg/L set by health authorities. It ranged from 2.15 to 7.65 mg/L, with a mean ± standard deviation of 4.99 ± 1.37 mg/L. Further to this, the minimum and maximum pH values were 6.57-7.10. It was interpreted that there was no significant association between the concentration of nitrate and pH value in drinking water. The Hazard Quotient (HQ) calculation recorded that all respondents recorded an HQ of less than 1, indicating no cancer risk to consumers. Conclusion: The nitrate levels in GFS water are relatively low and do not threaten human health. However, it is recommended to conduct assessments on a regular basis to guarantee the levels within the permissible limit of the Malaysian National Drinking Water Quality Standard (NDWQS).

Comparing Vegetation and Substrate Performances on Nutrient Removal and Biomass Establishment Using a Natural Swimming Pool Experiment

Natural swimming pools (NSPs) rely on the interaction of bog vegetation, bacteria, and substrate to maintain water quality. Nitrogen (N) and phosphorus (P) levels in NSPs are critical because of their involvement in eutrophication. We conducted a 15-week greenhouse study to address the significant literature gap regarding nutrient removal capabilities of substrates and vegetation in the low-nutrient environment of NSPs. We used mass balance analyses to compare the performances of four substrates [river gravel (control), recycled glass, expanded clay, expanded shale] and two plant species [blue flag iris (Iris versicolor) and lizard’s tail (Saururus cernuus)] under two flow conditions: free water surface and subsurface flow. At the end of the experiment, except for the recycled glass group, all other substrate groups reduced water nitrate (NO3) levels to less than 30 mg⋅L−1, the standard of the 2011 Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau (FLL) guidelines. However, only the expanded clay group closely approached the P standard (≤0.01 mg⋅L−1). Expanded clay and expanded shale demonstrated potential as substrates for NSP bogs. The final aboveground biomass dry weight was strongly negatively correlated with the final NO3 and P water concentrations. However, direct plant uptake proved insufficient to remove all nutrient inputs, especially for P. Except for the recycled glass group (34%), a significant portion of N (79%–90%) from total N added was removed by aboveground biomass. However, P uptake by biomass was substantially lower (18%–37%). With acceptable vigor and biomass accumulation, blue flag iris may be a suitable species for vegetated NSPs, whereas lizard’s tail is not because of uncertain establishment. Compared with controlling N, managing P for FLL standards in NSPs will be more challenging. Our work begins to fill the essential gap in the NSP literature regarding nutrient removal capabilities of substrates and vegetation. Future work should continue to study alternative substrates and plant species for P removal, particularly in field conditions and over longer periods.

Bimetallic Pd‐Sn Catalytic Electrodes from Deep Eutectic Solvents for Selective Nitrate Reduction Toward Nitrogen

AbstractNitrate is one of the most widespread water contaminants globally. Nitrate levels in groundwater and surface water can rise to unhealthy levels as a result of nitrogen fertilizer runoff from lawns and farms. This research aims to selectively convert nitrate to gaseous nitrogen using Palladium‐Tin (Pd‐Sn) bimetallic electrodes electrodeposited on stainless‐steel (SS). Inductively coupled plasma optical emission spectrometry, scanning electron microscope, and X‐ray diffraction are used to analyze the composition, surface morphology, and crystal structure of the electrodes. The XRD analysis reveals that the Pd‐Sn/SS electrode has a crystalline nature when a Pd molar ratio &gt;0.5 while an amorphous phase is detected over a Pd molar ratio (≤0.5). The electrochemical nitrate reduction is carried out in a 0.1 M HClO4 / 8 mM NaNO3 solution for 5 h using electrodes prepared in deep eutectic solvent (DES) system. The Pd0.93Sn0.07/SS electrode shows the best catalytic performance in terms of high nitrate conversion of 97%, N2 selectivity of 88%, and N2 yield of 86% compared to counter electrodes. These findings demonstrate a considerable impact of the electrode preparation process on nitrogen conversion, selectivity, and yield.

Using selectivity to evaluate aqueous- and resin-phase denitrification during biological ion exchange.

An increased fertilizer application for agricultural purposes has resulted in increased nitrate (NO3-) levels in surface water and groundwater around the globe, highlighting demand for a low-maintenance NO3- treatment technology that can be applied to nonpoint sources. Ion exchange (IEX) is an effective NO3- treatment technology and research has shown that bioregeneration of NO3- laden resins has the potential to minimize operational requirements and brine waste production that often prevents IEX application for decentralized treatment. In this work, batch denitrification experiments were conducted using solutions with low IEX selectivity capable of supporting the growth of denitrifying bacteria, while minimizing NO3- desorption from resins, encouraging resin-phase denitrification. Although only 15% of NO3- was desorbed by the low selectivity solution, this initial desorption started a cycle in which desorbed NO3- was biologically transformed to NO2-, which further desorbed NO3- that could be biotransformed. Denitrification experiments resulted in a 43% conversion rate of initially adsorbed NO3-, but biotransformations stopped at NO2- due to pH limitations. The balance between adsorption equilibria and biotransformation observed in this work was used to propose a continuous-flow reactor configuration where gradual NO3- desorption might allow for complete denitrification in the short retention times used for IEX systems.

Circular Sensing of Nitrate Levels in Water With Flexible Screen-Printed Sensors on Biodegradable Cellulose Substrate

Circular Sensing of Nitrate Levels in Water With Flexible Screen-Printed Sensors on Biodegradable Cellulose Substrate

Short-term climate change influence on surface water quality impacts from agricultural activities.

Climate change is a global phenomenon that directly affects agriculture by altering crop yield, nutritional quality, pests, and plant diseases. The North Aegean Basin located in Turkey has considerable agricultural importance due to its fertile soils. Agricultural activities have increased significantly and uncontrollably in the last decade, resulting in dramatic changes in nitrate and phosphorus levels in surface water within the watershed. Changes in climatic conditions have the potential to impact the quantity and quality of water resources. Best management practices (BMPs) are presently utilized as a planning tool to enhance the quality of water resources. To develop policies in this regard, it is necessary to evaluate the effectiveness of BMPs. To this end, this study aims to investigate the potential effect of climate change on the surface water quality of the North Aegean Basin. For the period between 2010 and 2030, global climate data retrieved from Concentration Pathway (RCP) scenarios 4.5 and 8.5 and regionally downscaled were used to feed the Soil and Water Assessment Tool (SWAT) model. The various potential BMP scenarios were developed and simulated in the hydrological model by considering the effects of climate change. The RCP4.5 scenario reduced the precipitation by 15.11%, while the RCP8.5 scenario reduced the precipitation by 10.97%. Decreased precipitation also affected the runoff and the nutrient loads and concentrations. As a result of the RCP4.5 simulation, TP and TN concentrations increased by 24.42% and 58.45%, respectively, in the IST_KEN014 station. Improvements were observed in TN and TP concentrations with the effect of applied BMP simulations. Also, the results revealed that the applied BMP scenarios may contribute to considerable reductions in nutrient loads. Considering the RCP4.5 scenario, BMPs reduced TN loads in the basin by 2.42-10.97%, while reducing TP loads by around 3.60-16.81%. Considering the RCP8.5 scenario, the BMPs reduced the TN loads in the basin between 2.21 and 10.04%, while they reduced the TP loads between 3.57 and 16.67%.

A comprehensive evaluation of water quality and its potential health risks using physicochemical indices in coastal areas of the Gulf of Suez, Red Sea

The Gulf of Suez plays a significant role in Egypt's economy and strategic position in the region, making it a critical waterway domestically and internationally due to being an essential hub for Egypt's oil and gas industry, housing numerous offshore oil and gas fields in the region. This paper aimed to comprehensively present the environmental status of the Gulf of Suez, the Red Sea, and pollution sources using one of the most fundamental ways to evaluate a water body. The Water Quality Index (WQI) measures nitrate levels in marine water and determines their potential harm to human health and the ecosystem. Excessive amounts of nitrate can pose non-carcinogenic health risks. Trophic state index (TSI), trophic index (TRIX), and Organic Pollution Index (OPI) are practical applications for surface water quality investigation and categorization based on contamination level. Principal Component Analysis (PCA), and Cluster Analysis (CA), were used to get better information for the studies on the water quality of surface waters. This study tested 38 subsurface locations during February 2021 for physical, chemical, microbiological, and nutritional salts. The WQI revealed that 71.23% of seawater samples were classified as having good water quality. However, TRIX and TSI metrics indicated eutrophication, with an average mean of 55.20, categorizing the water quality fairly. OPI values ranged between (3.50–3.75) which can be classified as moderate water quality. Finally, the current study's findings indicated the NO3− non-carcinogenic health hazards (HQ < 1) in all groups, but children are at a higher risk of NO3− exposure. Therefore, it can be concluded that Periodic assessments of water quality and strict regulations are necessary to safeguard this vital resource from pollution and ensure the well-being of future generations.