High Nitrate Research Articles

The interaction between dietary nitrates/nitrites intake and gut microbial metabolites on metabolic syndrome: a cross-sectional study.

Metabolic syndrome (MetS) prevalence has increased globally.The evidence shows thatdiet and gut microbial metabolites includingtrimethylamine N-oxide (TMAO) and kynurenine (KYN) play an important role in developing MetS. However, there is a lack of evidence on associations between between diet and these metabolites. This study aimed to investigate the interaction between dietary nitrate/nitrite and gut microbial metabolites (TMAO, KYN) on MetS and its components. This cross-sectional study included 250 adults aged 20-50 years. Dietary intake was assessed using food frequency questionnaires (FFQ), and serum TMAO and KYN levels were measured. MetS was defined usingthe National Cholesterol Education Program Adult Treatment Panel (NCEP ATP III) criteria. The ATPIII index revealed an 11% prevalence of metabolic syndrome among the study participants. After adjusting for confounders, significant positive interactions were found: High animal-source nitrate intake and high TMAO levels with elevated triglycerides (TG) (p interaction = 0.07) and abdominal obesity (p interaction = 0.08). High animal-source nitrate intake and high KYN levels with increased TG (p interaction = 0.01) and decreased high-density lipoprotein cholesterol (HDL) (p interaction = 0.01).Individuals with high animal-source nitrite intake and high TMAO levels showed increased risk of hypertriglyceridemia (OR: 1.57, 95%CI: 0.35-2.87, p = 0.05), hypertension (OR: 1.53, 95%CI: 0.33-2.58, p = 0.06), and lower HDL (OR: 1.96, 95%CI: 0.42-2.03, p = 0.04). Similarly, high animal-source nitrite intake with high KYN levels showed lower HDL (OR: 2.44, 95%CI: 1.92-3.89, p = 0.07) and increased risk of hypertension (OR: 2.17,95%CI: 1.69-3.40, p = 0.05). Conversely, Negative interactions were found between high plant-source nitrate/nitrite intake with high KYN and TMAO levels on MetS and some components. There is an interaction between dietary nitrate/nitrite source (animal vs. plant) and gut microbial metabolites (TMAO and KYN) on the risk of of MetS and its components. These findings highlight the importance of considering diet, gut microbiome metabolites, and their interactions in MetS risk assessment.

Impact assessment of the effects of the former uncontrolled landfill of Sidi Yahya Oujda (Morocco) on groundwater using physicochemical, geological and electrical triple approaches

This study is part of the geophysical mapping of the former site of the uncontrolled Sidi Yahya Oujda landfill. It also aims to show the contribution of the integrated interpretation of geological and geophysical data in the diagnosis of illegal dump sites. The application was made on the rehabilitated site of the former uncontrolled Oujda landfill located in Sidi-Yahya, which was closed in 2005. Geological and geophysical studies by electrical resistivity tomography (TRE) were carried out at the site level. Nine 475 m long TRE profiles with an investigation depth of up to 110 m were generated to image the subsoil. Analysis of the physicochemical and metallic composition of the leachate from this site and the groundwater taken from 3 nearby wells revealed significant pollution of the leachate with a COD of 12780 mg. O2/L and a BOD5 of 525.34 mg. O2/L. The groundwater had high electrical conductivity (average of 3.9 mS/cm), chloride content (710 mg/L average) and nitrate content (74.62 mg/L average). The metal concentrations in the leachate and groundwater far exceeded the Moroccan standards, with high average values for zinc (619.22 μg/L), copper (318.12 μg/L), nickel (233.76 μg/L), chromium (169.16 μg/L), L) and iron (12940 μg/L). Geologically, a context was highlighted with lateral lithological variations and the presence of faults. The waste/leachate layer has low resistivity values (<10 Ω m) and a thickness of up to 25 m. It rests on terrains of different geological natures. In the southern part of the site, there is a layer of red clay with a thickness of up to 50 m and low resistivities (<10 Ω m), which overlies a layer of limestone with high resistivity values (>100 Ω m). In the northern part, we encounter a discontinuous and thin layer of fractured dolomites with resistivities greater than 50 Ω m. This layer of dolomite rests on a layer of clays.

A Circum‐Antarctic Plankton Isoscape: Carbon Export Potential Across the Summertime Southern Ocean

AbstractThe Southern Ocean accounts for ∼30% of the ocean's CO2 sink, partly due to its biological pump that transfers surface‐produced organic carbon to deeper waters. To estimate large‐scale Southern Ocean carbon export potential and characterize its drivers, we measured the carbon and nitrogen isotope ratios of surface suspended particulate matter (δ13CSPM, δ15NSPM) for samples collected in summer 2016/2017 during the Antarctic Circumnavigation Expedition (364 stations). Concurrent measurements of phytoplankton community composition revealed the dominance of large diatoms in the Antarctic and nano‐phytoplankton (mainly haptophytes) in open Subantarctic waters. As expected, δ13CSPM was strongly dependent on pCO2, with local deviations in this relationship explained by phytoplankton community dynamics. δ15NSPM reflected the nitrogen sources consumed by phytoplankton, with higher inferred nitrate (versus recycled ammonium) dependence generally coinciding with higher micro‐phytoplankton abundances. Using δ15NSPM and a two‐endmember isotope mixing model, we quantified the extent of nitrate‐ versus ammonium‐supported growth, which yields a measure of carbon export potential. We estimate that across the Southern Ocean, 41 ± 29% of the surface‐produced organic carbon was potentially exported below the seasonal mixed layer during the growth season, with maximum export potential (50%–99%) occurring in the Antarctic Circumpolar Current's southern Boundary Zone and near the (Sub)Antarctic islands, reaching a minimum in the Subtropical Zone (<33%). Alongside iron, phytoplankton community composition emerged as an important driver of the Southern Ocean's biological pump, with large diatoms dominating regions characterized by high nitrate dependence and elevated carbon export potential and smaller, mainly non‐diatom taxa proliferating in waters where recycled ammonium supported most productivity.

Transcriptome analysis of differentially expressed genes in rice seedling leaves under different nitrate treatments on resistance to bacterial leaf blight.

Nitrogen (N), as one of the most abundant mineral elements in rice, not only is the primary limiting factor for rice yield, but also impacts plant disease resistance by modulating plant morphology, regulating biochemical characteristics, as well as enhancing metabolic processes. Bacterial blight, a severe bacterial disease caused by Xanthomonas oryzae pv. oryzae (Xoo), significantly impairing rice yield and quality. Previous studies have shown that moderate application of nitrate nitrogen can improve plant disease resistance. However, further exploration is urgently required to investigate the involvement of the nitrate nitrogen signaling pathway in conferring resistance against bacterial leaf blight. In this study, we employed transcriptome sequencing to analyze the differentially expressed genes under various concentrations of nitrate supply duringrice bacterial blight infection. Our research reveals that nitrate nitrogen supply influences rice resistance to bacterial leaf blight. Through transcriptomic profiling of rice leaves inoculated under different nitrate nitrogen concentrations, we identified 4815 differentially expressed genes (DEGs) among four comparison groups, with notable differences in DEG enrichment between low and high nitrate nitrogen conditions, with some members of the NPF family implicated and we preliminarily elucidated the molecular regulatory network in which nitrate nitrogen participates in bacterial leaf blight resistance. Our findings provide a novel insight into a mechanism involving the nitrate nitrogen drive wider defense in rice.

Simultaneous determination of six nitroaromatic compounds and three anions in environmental matrices using a liquid chromatography-ion chromatography coupled system

Nitroaromatic compounds are used extensively in various fields such as dyes, pesticides, spices, pharmaceuticals, and explosives. However, the residual raw materials of these compounds accumulate in the environment and pose serious risks to human health. Chronic exposure to low concentrations of nitroaromatic compounds can cause anemia, cancer, and organ damage. Currently, Fenton oxidation and natural bioremediation are the processes most often used to eliminate nitroaromatic compounds from environmental water and soil. According to previous research, the presence of inorganic anions such as chloride, nitrite, and nitrate ions in the environmental matrix exerts an inhibitory effect on the biodegradation of nitroaromatic compounds. Furthermore, high nitrate levels in drinking water can lead to the production of nitrosamine carcinogens, which affect ecological safety and human health, in water bodies. Thus, the simultaneous determination of nitroaromatic compounds and chloride, nitrite, and nitrate ions in environmental soil and water matrices is critical for selecting appropriate nitroaromatic compound degradation methods and monitoring surface water quality. Traditional detection methods require two sample pretreatment steps and two instrumental analytical techniques to determine nitroaromatic compounds and inorganic anions in environmental matrices; moreover, these methods are time consuming, labor intensive, and error prone. Therefore, in this study, a method that combines high performance liquid chromatography (HPLC) and ion chromatography (IC) was developed to simultaneously detect nitroaromatic compounds and anions in environmental matrices. In this method, sample enrichment was achieved through bulk injection and enrichment column collection, which greatly simplified the pretreatment process. The HPLC instrument was connected to the IC instrument using two six-way valves and an enrichment column. The system operation can be divided into four stages: (A) sample loading to the quantitative ring, (B) separation of nitroaromatic compounds and anions, (C) enrichment of anions in an AG20 column, and (D) simultaneous determination of nitroaromatic compounds and anions by HPLC and IC, respectively. The time of the anions flowing out of the C18 column was determined by directly connecting the C18 column to a conductivity detector. Based on the retention times of the anions, the switching time of the six-way valve was optimized to ensure that the anions completely entered the IC column, thereby ensuring the accuracy of the method. During the chromatographic analysis stage, nitroaromatic compounds were separated and analyzed by HPLC system with a mobile phase composed of potassium phosphate buffer (pH 7.0) and acetonitrile (60∶40, v/v) at a flow rate of 1.0 mL/min; in the IC system, the anions were separated and analyzed using a 20 mmol/L sodium hydroxide aqueous solution as the mobile phase under a suppression current of 50 mA. Both anions and nitroaromatic compounds exhibited strong linear correlations within certain concentration ranges, with correlation coefficients greater than 0.993. The recoveries of the nitroaromatic compounds and anions ranged from 88.20% to 105.38% at three spiked levels, with relative standard deviations ranging from 2.0% to 11.5%. The contents of six nitroaromatic compounds and three anions in five surface water and five soil samples were determined using the developed method. Although no nitroaromatic compounds were detected in these samples, the three anions were detected at contents ranging from 0.41 to 55.3 mg/L in surface water samples, and 0.56 to 30.2 mg/kg in soil samples. Methodological validation and actual sample detection demonstrated that the proposed method has a high degree of automation, simple operation, good repeatability, high accuracy, wide applicability, and high sensitivity. Thus, this method is suitable for the rapid determination of chloride, nitrite, nitrate ions and nitroaromatic compounds in soil and water and can be extended to the simultaneous determination of inorganic ions and organic matters in other samples.

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.

Mixotrophic denitrification: A study on the removal of high nitrate concentration from piggery wastewater by biofilter reactors

The treatment of piggery wastewater through anaerobic fermentation and subsequent irrigation on farmland has been found to pose a risk of nitrate-nitrogen pollution in groundwater, thereby posing potential threats to human health. The scientific investigation of employing heterotrophic/autotrophic (mixotrophic) denitrification as a means to address the issue of farm wastewater containing elevated levels of nitrate nitrogen has garnered significant attention. This study employed sulfur monomers, limestone, and corn cob as microbial carriers within a biofilter system to facilitate the heterotrophic denitrification process of piggery wastewater fermentation broth. The efficacy of mixotrophic denitrification was found to surpass that of sulfur-limestone autotrophic denitrification in the treatment of nitrate-nitrogen wastewater with elevated concentrations of nitrate-nitrogen. This was evidenced by higher rates of denitrification, as well as reduced production of sulphate ions and alkalinity. The experiments on mixotrophic denitrification reaction observed a positive correlation between the content of corn cob and the relative abundance of microbial flora. Specifically, the relative abundance of Proteobacteria at the phylum level showed an increasing trend. Additionally, there was a proportional increase in the relative abundance of various other flora at the genus level.

Assessment of nitrate contamination of domestic wells and remedial treatment by electrocoagulation

Natural water contaminated with nitrates can pose serious problems for human health and aquatic ecosystems. Thus, effective, and low-cost treatment systems that can be implemented on both large and small scales are needed. The main goals of this work were to quantify nitrate pollution of groundwater (i.e., underground well water used for drinking purposes), to identify its causes, to evaluate the performance of the electrocoagulation (EC) process in nitrate removal, optimizing the treatment procedure using synthetic water, and to estimate the process cost. A total of thirty domestic wells, located in Sidi Bel Abbes city in North-West Algeria, used for drinking water were subject to sampling. Results indicated that most of the wells had nitrate contents that exceeded the World Health Organization (WHO) guideline value as well as the Algerian permissible limit of 50 mg.L−1, with a maximum NO3- concentration of 162 mg.L−1. The pollution was presumed to be due to agricultural activity, human and animal waste, and the nature of the soil. The EC treatment tests with aluminum electrodes exhibited a high nitrate removal efficiency of 90% at a current density of 5.12 mA.cm−2, electrolysis time 15 min, pH 8.8, agitation speed 400 rpm and at an initial nitrate concentration of 50 mg.L−1. Under optimum operating conditions, nitrate removal was 88% for an initial [NO3-] of 87 mg.L−1 in groundwater. The operating cost was estimated at 0.27 US $/m3 or 0.12 US $/Kg nitrate removed. The findings from this study showed that EC is an economically viable technique for dealing with nitrate contamination for small-scale water treatment applications.

Oxygen vacancy-regulated nanorod array electrodes for boosting the electrocatalytic synthesis of ammonia from nitrate wastewater.

The adsorption of nitrate is the key to enhancing the electrocatalytic nitrate reduction reaction (NitRR). Herein, a typical hydrolysis-coupled redox (HCR) reaction has been designed to prepare unique 3D Cu/Fe2O3 core-shell nanorod array cathodes with controllable oxygen vacancy concentrations for NitRR. The optimal Cu/Fe2O3-13 achieves a high nitrate conversion of 99.10% and ammonia selectivity of 98.30%. The outstanding electrochemical performance is attributed to the enhancement mechanism of OVs and a unique nanorod array structure with a high density of surface-exposed OVs and high-throughput transport pathways for ion-aspects.

Health Risk Assessment of Nitrate in Drinking Water with Potential Source Identification: A Case Study in Almaty, Kazakhstan.

Infant mortality in Kazakhstan is six times higher compared with the EU. There are several reasons for this, but a partial reason might be that less than 30% of Kazakhstan's population has access to safe water and sanitation and more than 57% uses polluted groundwater from wells that do not comply with international standards. For example, nitrate pollution in surface and groundwater continues to increase due to intensified agriculture and the discharge of untreated wastewater, causing concerns regarding environmental and human health. For this reason, drinking water samples were collected from the water supply distribution network in eight districts of Almaty, Kazakhstan, and water quality constituents, including nitrate, were analyzed. In several districts, the nitrate concentration was above the WHO and Kazakhstan's maximum permissible limits for drinking water. The spatial distribution of high nitrate concentration in drinking water was shown to be strongly correlated with areas that are supplied with groundwater, whereas areas with lower nitrate levels are supplied with surface water sources. Based on source identification, it was shown that groundwater is likely polluted by mainly domestic wastewater. The health risk for infants, children, teenagers, and adults was assessed based on chronic daily intake, and the hazard quotient (HQ) of nitrate intake from drinking water was determined. The non-carcinogenic risks increased in the following manner: adult < teenager < child < infant. For infants and children, the HQ was greater than the acceptable level and higher than that of other age groups, thus pointing to infants and children as the most vulnerable age group due to drinking water intake in the study area. Different water management options are suggested to improve the health situation of the population now drinking nitrate-polluted groundwater.

Irrigation and nitrogen fertiliser optimisation in protected vegetable fields of northern China: Achieving environmental and agronomic sustainability

Globally, sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO3−) losses from protected vegetable field systems. Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems. The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China. The treatments applied at each field site were: 1) a high N and high irrigation input treatment (HNHI); 2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI). Results showed that the mean annual leached total nitrogen loads from the HNHI, LNHI and LNLI treatments were 325, 294 and 257 kg N ha−1 in the fluvo-aquic soil, 114, 100 and 78 kg N ha−1 in the cinnamon soil and 79, 68 and 57 kg N ha−1 in the black soil, respectively. The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas. A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8% of the variation of leached N loads, respectively. Correspondingly, reducing irrigation water by 21.5% decreased leached N loads by 20.9%, while reducing manure N and chemical N inputs by 22 and 25% decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.

Boosting the Electroactivity of Porous Ni2P/Pd6P Nanorods for Nitrate to Ammonia Through Hydrogen Spillover Effect

AbstractIn contrast to the energy‐intensive Haber‐Bosch process, the electroreduction of nitrate to ammonia presents a promising alternative. In this work, the Ni2P/Pd6P nanorods (named NiPdP‐NR) are successfully synthesized by using a simple phosphating process with NiIIPdII‐dimethylglyoxime complex (NiIIPdII‐DMG) nanorods as the precursor. Density functional theory calculations and electrochemical experiments prove that the introduction of Pd facilitates hydrogen spillover from Pd to Ni2P modulates the surface electronic structures, and therefore improves the catalytic kinetics of nitrate reduction ultimately. According to the dynamic experiment, the as‐prepared NiPdP‐NR shows high nitrate conversion efficiency (90.6%), selectivity of NH3 (93.4%), high Faradic efficiency (92.6%), and NH3 yield rate (0.908 mmol h−1 mgcat−1) for the nitrate reduction.

Comparative Analysis of Leaf Vegetable Productivity, Quality, and Profitability among Different Cultivation Modes: A Case Study

In recent years, vegetable production has been in the transitional stage from traditional cultivation mode to modern cultivation mode. Therefore, evaluating the actual productivity and economic benefits of different cultivation modes is instructive for leafy vegetable production. This research chose a vegetable production company (Shanghai, China) as a demonstration case to cultivate various leaf vegetables under different cultivation modes (hydroponic, substrate, and soil cultivation). By investigating the yield and quality of vegetables, as well as all production costs and selling prices, we drive a comparative evaluation of comprehensive features and economic benefits of different cultivation modes. The results showed that leafy vegetables cultivated by hydroponic mode gain the highest fresh weight at the early growth stage, but the greatest unit yield (0.98~1.21 kg·m−2) emerged under the soil cultivation mode. Vegetables grown under substrate mode had the best comprehensive quality with high soluble solids content and low nitrate content. The unit costs of the soilless cultivation modes (8.26~10.3 CNY·m−2) were 3–4-fold higher than that of soil cultivation, mainly due to the high fixed costs and input costs, especially for substrate mode. According to actual prices, the soil cultivation mode had the highest economic benefits as a whole (4.83~8.83 CNY·m−2), and only hydroponic cabbage which had comparable yield gained considerable benefits (8.94 CNY·m−2). Quality-based pricing scheme can make substrate mode achieve profitability. The pricing scheme that guarantees a 40% revenue is within acceptable limits for consumers. Based on this actual production case, it can be concluded that a low unit yield of hydroponic mode and a high unit cost of substrate mode are the predominant factors affecting their profitability and economic viability.

Unveiling the power of COD/N on constructed wetlands in a short-term experiment: Exploring microbiota co-occurrence patterns and assembly dynamics

Constructed wetlands (CWs) are a cost-effective and environmentally friendly wastewater treatment technology. The influent chemical oxygen demand (COD)/nitrogen (N) ratio (CNR) plays a crucial role in microbial activity and purification performance. However, the effects of CNR changes on microbial diversity, interactions, and assembly processes in CWs are not well understood. In this study, we conducted comprehensive mechanistic experiments to investigate the response of CWs to changes in influent CNR, focusing on the effluent, rhizosphere, and substrate microbiota. Our goal is to provide new insights into CW management by integrating microbial ecology and environmental engineering perspectives. We constructed two groups of horizontal subsurface flow constructed wetlands (HFCWs) and set up three influent CNRs to analyse the microbial responses and nutrient removal. The results indicated that increasing influent CNR led to a decrease in microbial α-diversity and niche width. Genera involved in nitrogen removal and denitrification, such as Rhodobacter, Desulfovibrio, and Zoogloea, were enriched under medium/high CNR conditions, resulting in higher nitrate (NO3--N) removal (up to 99 %) than that under lower CNR conditions (<60 %). Environmental factors, including water temperature (WT), pH, and phosphorus (P), along with CNR-induced COD and NO3--N play important roles in microbial succession in HFCWs. The genus Nitrospira, which is involved in nitrification, exhibited a significant negative correlation (p < 0.05) with WT, COD, and P. Co-occurrence network analysis revealed that increasing influent CNR reduced the complexity of the network structure and increased microbial competition. Analysis using null models demonstrated that the microbial community assembly in HFCWs was primarily driven by stochastic processes under increasing influent CNR conditions. Furthermore, HFCWs with more stochastic microbial communities exhibited better denitrification performance (NO3--N removal). Overall, this study enhances our understanding of nutrient removal, microbial co-occurrence, and assembly mechanisms in CWs under varying influent CNRs.

Investigating the applicability and assumptions of the regression relationship between flow discharge and nitrogen concentrations for load estimation

The regression relationship between water discharge rates and nutrient concentrations can provide a quick and straightforward way to estimate nutrient loads. However, recent studies indicated that the relationship might produce large biases in load estimates and, therefore, may not be applicable in certain types of cases. The goal of this study is to explore the theoretical reasons behind the selective applicability of the regression relationship between flow rates and nitrate + nitrite concentrations. For this study, we examined daily flow and nitrate + nitrite concentration observations made at the outlets of 22 watersheds monitored by the Heidelberg Tributary Loading Program (HTLP). The statistical relationship between the flow rates and concentrations was explored using regression equations offered by the LOAD ESTimator (LOADEST). Results demonstrated that the use of the regression equations provided nitrate + nitrite load estimates at acceptable accuracy levels (NSE≥0.35 and |PBIAS|≤30.0%) in 14 watersheds (64 % of 22 study watersheds). The regression relationships provided highly biased results at eight watersheds (36 %), implying their limited applicability. The heteroscedasticity of the residuals led to the high bias and resulting inaccurate regression, which was commonly found in watersheds where low flow had high nitrate + nitrite concentration variations. Conversely, the regression relationships provided acceptable accuracy for watersheds that had a relatively constant variance of the nitrate + nitrite concentrations. The results indicate that the homoscedasticity of residuals is the key assumption to be satisfied to estimate nitrate + nitrite loads from a statistical regression between flow discharge and nitrate + nitrite concentrations. The transport capacity (capacity-limited) concept implicitly assumed in the regression relationship between flow discharge and nitrate + nitrite concentrations is not always applicable, especially to agricultural areas in which nitrate + nitrite loads are highly variable depending on management practices (supply-limited). The findings suggest that the regression relationship should be carefully applied to areas in which intensive agricultural activities, including crop management and conservation practices, are implemented. Thus, the transport capacity concept is reasonably regarded to contribute to the homoscedasticity of residuals.

CONTAMINAÇÃO POR NITRATO EM ÁGUAS DE POÇOS RASOS DESTINADAS AO CONSUMO HUMANO EM ICOARACI, MUNICÍPIO DE BELÉM, ESTADO DO PARÁ

The research aims to assess the water quality of shallow wells utilized by the local inhabitants of the Parque Guajará neighborhood, located in the Icoaraci District of Belém Municipality, State of Pará. This assessment was conducted in accordance with the criteria delineated by Ordinance GM/MS nº 888, an edict established by the Ministry of Health. In the year 2016, a series of samples were collected from 15 specifically chosen shallow wells. This sampling was arranged to align with the distinct climatic patterns of the region, spanning the rainy season (January and May) and the drier period (August and October). The investigation analyzed the following parameters: pH, electrical conductivity, nitrite, ammonium, and nitrate content. During the time of the sample collection phase, recorded pH values oscillated between 3.93 and 6.42, while the measurements of electrical conductivity exhibited a peak at 527 µS/cm. Notably, ammonium concentrations peaked during the rainy season at 6.01 mg/L, whereas nitrite levels reached their peak during the less rainy season at 0.44 mg/L. High nitrate levels were particularly observed, predominantly during the rainy season, increasing up to 64.03 mg/L. Signs of a nitrification process could be seen within the samples from two wells under investigation. Statistical analysis highlighted positive correlations between electrical conductivity and nitrate levels, as well as between pH and ammonium concentrations. Based on these data, it became evident that nitrate contamination was pervasive in the residual groundwater of the shallow wells. This nitrate contamination, a fundamental concern throughout the sampling period, under scored the significant influence of septic tank systems on the analyzed water. This contamination, in turn, threatens the well-being of the people who depend on these water sources for consumption, thereby requiring urgent attention.

Weak magnetic carriers reduce nitrite accumulation and boost denitrification at high nitrate concentrations by enriching functional bacteria and enhancing electron transfer

Biological denitrification is the dominant method for NO3− removal from wastewater, while high NO3− leads to NO2− accumulation and inhibits denitrification performance. In this study, different weak magnetic carriers (0, 0.3, 0.6, 0.9 mT) were used to enhance biological denitrification at NO3− of 50–2400 mg/L. The effect of magnetic carriers on the removal and mechanism of denitrification of high NO3− was investigated. The results showed that 0.6 and 0.9 mT carriers significantly enhanced the TN removal efficiency (>99%) and reduced the accumulation of NO2− (by > 97%) at NO3− of 1200–2400 mg/L 0.6 and 0.9 mT carriers stimulated microbial electron transport by improving the abundances of coenzyme Q-cytochrome C reductase (by 4.44–23.30%) and cytochrome C (by 2.90–16.77%), which contributed to the enhanced elimination of NO3− and NO2−. 0.6 and 0.9 mT carriers increased the activities of NAR (by 3.74–37.59%) and NIR (by 5.01–8.24%). The abundance of narG genes in 0.6 and 0.9 mT was 1.47–2.35 and 1.38–1.75 times that of R1, respectively, and the abundance of nirS genes was 1.49–2.83 and 1.55–2.39 times that of R1, respectively. Denitrifying microorganisms, e.g., Halomonas, Thauera and Pseudomonas were enriched at 0.6 and 0.9 mT carriers, which benefited to the advanced denitrification performance. This study suggests that weak magnetic carriers can help to enhance the biological denitrification of high NO3− wastewater.

Phosphoregulation in the N-terminus of NRT2.1 affects nitrate uptake by controlling the interaction of NRT2.1 with NAR2.1 and kinase HPCAL1 in Arabidopsis.

NRT2.1, the major high affinity nitrate transporter in roots, can be phosphorylated at five different sites within the N- and the C-terminus. Here, we characterized the functional relationship of two N-terminal phosphorylation sites, S21 and S28, in Arabidopsis. Based on a site-specific correlation network, we identified a receptor kinase (HPCAL1, AT5G49770), phosphorylating NRT2.1 at S21 and resulting in active nitrate uptake. HPCAL1 itself was regulated by phosphorylation at S839 and S870 within its kinase domain. In the active state, when S839 was dephosphorylated and S870 was phosphorylated, HPCAL1 was found to interact with the N-terminus of NRT2.1, mainly when S28 was dephosphorylated. Phosphorylation of NRT2.1 at S21 resulted in a reduced interaction of NRT2.1 with its activator NAR2.1, but nitrate transport activity remained. By contrast, phosphorylated NRT2.1 at S28 enhanced the interaction with NAR2.1, but reduced the interaction with HPCAL1. Here we identified HPCAL1 as the kinase affecting this phospho-switch through phosphorylation of NRT2.1 at S21.

Comparative evaluation of biometrical and biochemical characteristics of three Rumex representatives: &lt;i&gt;Rumex acetosa&lt;/i&gt; L., &lt;i&gt;Rumex sanguineus&lt;/i&gt; L. and &lt;i&gt;Rumex confertus&lt;/i&gt; Willd.

Increase in green vegetables popularity in nutrition and medicine promotes investigations of new cultivar and hybrid biochemical parameters. Nutritional value and antioxidant status of three Rumex representatives: Rumex acetosa L. (Krupnolistny cv.), Rumex sanguineus L. (prospect genotype) and Rumex confertus Willd. were studied. Antioxidant defense parameters (total antioxidant activity, polyphenol and ascorbic acid content) decreased in accordance to: Rumex sanguineus L. &gt; Rumes confertus Willd. &gt; Rumex acetosa L. Thus the ascorbic acid content in bloody dock (R. sanguineus) reached 129 mg/100 g which was 1.48 times higher than in Russian dock (R. confertus) and 3.17 times higher than in garden sorrel (R. acetosa). The total chlorophyll content was also the highest in bloody dock (17.74 mg/g d.w.) compared to 15.88 mg/g in R. confertus and 13.07 mg/g in R. acetosa leaves. The new R. sanguineus genotype was characterized by high decorative properties and demonstrated twice higher oxalic acid content compared to R. acetosa, Krupnolistny cv., and 1.5 times higher value than in R. confertus. High decorative and medicinal value of R. sanguineus was connected to a great extent with the intensive anthocyanin accumulation reaching 7.2% and high nitrate content. The results of the present study indicate high prospects of R. sanguineus genotype utilization in landscape design, food industry and medicine.

Comparison of avian diversity between managed and unmanaged wetlands in Patna, Bihar, India

Abstract We compared the bird diversity of a managed (Rajdhani Jalashay) and an unmanaged wetland (Mustafapur) in Patna, Bihar, India. We recorded bird species by using point counts and fixed-route monitoring. At Rajdhani Jalashay, a total of 73 species were recorded, of which 15 species were winter visitors. Two species were in the Near-threatened category: Ferruginous Duck (Aythya nyroca) and Alexandrine Parakeet (Psittacula eupatria), while the others were of least concern. At Mustafapur wetland, 67 species were recorded with 11 species as winter visitors. Simpson’s species diversity index was 0.78 at Rajdhani Jalashay, and 0.81 at Mustafapur wetland. The number of species of waders was 17 at Mustafapur wetland and 11 at Rajdhani Jalashay. The total number of Lesser Whistling-duck (Dendrocygna javanica), a resident bird was almost double (526) at Mustafapur wetland than that at Rajdhani Jalashay (234). The nitrate level was twice higher and the phosphate level was four times higher at Mustafapur wetland than those at Rajdhani Jalashay. The difference in species number and composition between the two wetlands may be attributed to the eutrophication resulting from high nitrate and phosphate levels at Mustafapur wetland. Unfortunately, the Mustafapur wetland is under threat due to human influences. The protection and sustainable management of natural wetlands is required for saving the biodiversity of the area.