Guideline Values Research Articles

EVALUATION OF WATER POLLUTION STATUS OF TRIYUGA RIVER IN UDAYAPUR DISTRICT, NEPAL

The present investigation has been conducted to assess the status of physiochemical and microbiological parameters to understand the present scenario of water quality at Triyuga River water at Belaka municipality of Udayapur district, Nepal. The temperature ranged from 180C to 200C, the TDS value ranged from 89 mg/L to 112 mg/L and were below the WHO guideline value of 1200 mg/L, the pH values of the surface water sources in the present study were found to be alkaline ranging above from 7.6 to 7.9 were found within the range of WHO guideline value of 6.5-8.5. Similarly the values of dissolved oxygen ranged from 6.4 mg/L to 10.4 mg/L and were above the WHO guideline value of 5 mg/L, the bicarbonate (HCO3) value ranged from 105 mg/L to 125 mg/L and were below the WHO guideline value of 125-350 mg/L, the values of Nitrate ranged from 3 mg/L to 5 mg/L and were below the WHO guideline of 50 mg/L, the values of Nitrite ranged from 0.3 mg/L to 0.5 mg/L, the value of Ammonium ranged from 0 mg/L to 0.3 mg/L, the values of Iron ranged from 1 mg/L to 1.5 mg/L and were above the WHO guideline of 0.3 mg/L and the phosphate was not detected in all the three different sites of surface water samples. The fecal coliform was found to be positive in all the samples and the value of fecal coliform recorded was 15, 15 and 21 MPN/100ml in Site I, II and III respectively.

Human health risk assessment and uncertainty analysis of silver nanoparticles in water.

Despite frequent detection in environmental waters, literature which quantifies the health risk of silver nanoparticles (Ag NPs) through oral ingestion is scarce. This study compiled literature data to find the removal of Ag NPs from different treatment schemes (i.e., natural, engineered, or hybrid). Ag NP concentrations were found either in surface water or in groundwater based on where the effluent of treatment schemes was discharged, i.e.,either in surface water or in groundwater. Monte-Carlo simulation was carried out for probabilistic assessment of health risks for children for two hypothetical exposure scenarios: (a) ingesting river water while swimming and (b) drinking groundwater. Bio-accessible fraction, dietary metal adsorption factor, and concentrations of silver ions were incorporated to simulate realistic situations. Different treatment schemes were ranked for their nanoparticles' removal efficiency with respect to (i) exceedance probability from guideline value and (ii) health risk to children. Hybrid treatment combinations, i.e., conventional primary and secondary treatment units followed by nature-based units (constructed wetlands and soil aquifer treatment), were ranked the best. The health risk value was found to be less than 1, with the 99th percentile value less than 10-3 in all cases. The maximum allowable concentration of Ag NPs was found to be as low as 1.43 mg/L for groundwater, suggesting probable potential for risk. Uncertainty analysis revealed that the uncertainty of the influent NPs concentration in raw wastewater contributes > 99% to the variance of the hazard index. The results of this work indicate that the use of natural treatment technologies with existing engineered treatments provides higher nanoparticle removal from wastewater without the requirement of any tertiary treatment unit.

The association between clustering based on composition of volatile organic compound in indoor air and building-related symptoms

Volatile organic compounds (VOCs) have been suspected to cause building-related symptoms (BRSs). Although some studies investigated the association between BRSs and VOCs in indoor air, those results were inconsistent. This study investigated the contamination status of VOCs in the indoor air of 154 houses in Japan. Additionally, these samples were grouped by hierarchical clustering analysis based on the VOC composition, and the relationship between a VOC cluster and the BRSs was investigated. The median concentration of the sum of VOCs (ΣVOCs) was 140 μg m−3 (range: 18–3500 μg m−3). The levels of acetaldehyde in four samples and p-dichlorobenzene in one sample exceeded the guideline value. As a result of the hierarchical clustering analysis, the samples in this study were divided into six characteristic clusters based on the VOC composition. The ΣVOCs in cluster 1 were significantly lower than those in other clusters. In cluster 2, acyclic and aromatic hydrocarbons were dominant. Cluster 3 had a relatively high proportion of limonene. In cluster 4, the concentrations and composition ratios of α-pinene were higher than those of other clusters. In cluster 5, p-dichlorobenzene accounted for 42 %–72 % of the total VOCs. Cluster 6 had a relatively high proportion of decamethyl cyclopentasiloxane. This clustering likely depended on the construction of houses and lifestyles. As a result of logistic regression analysis, cluster 5 was associated with the cough symptoms of the BRSs. The results of the present study suggest that investigating the association between VOCs and BRSs is necessary to consider not only total concentrations such as TVOC and ΣVOCs but also VOC composition.

Toxicity of herbicides to the marine microalgae Tisochrysis lutea and Tetraselmis sp.

Pesticides are ubiquitous in the catchments of the Great Barrier Reef (GBR) and regularly discharge into the nearshore waters. Effective management of pesticides requires suitable water quality guideline values (WQGVs), and further ecotoxicological data for many pesticides are needed to improve the reliability of environmental risk assessments. To help address this issue, toxicity thresholds were determined to two species of tropical marine microalgae Tisochrysis lutea and Tetraselmis sp. for a suite of herbicides detected in the GBR. Photosystem II (PSII) herbicides significantly reduced growth with no effect concentration (NEC) and 10% effect concentration (EC10) values spanning two orders of magnitude from 0.60 µg L−1 for diuron to 60 µg L−1 for simazine across both species. However, growth was insensitive to the non-PSII herbicides. The NEC/EC10 thresholds for most herbicide-microalgae combinations were greater than recent WQGVs intended to protect 99% of species (PC99); however, metribuzin was toxic to T. lutea at concentrations lower than the current PC99 value, which may have to be revisited. The toxicity thresholds for alternative herbicides derived here further inform the development of national and GBR-specific WQGVs, but more toxicity data is needed to develop WQGVs for the > 50 additional pesticides detected in catchments of the GBR.

The Drawback of Optimizing Air Cleaner Filters for the Adsorption of Formaldehyde

Air cleaners with activated carbon (AC) filters for the adsorption of gaseous pollutants are often used to improve indoor air quality. As formaldehyde is a common and health-relevant indoor air pollutant, many testing standards for air cleaners, such as GB/T 18801:2015, require the cleaning efficacy to be tested with this substance. This often persuades manufacturers to optimize the employed filters specifically for formaldehyde. However, in regions where indoor formaldehyde levels are far below the guideline values, other gaseous pollutants might be more relevant. Thus, the question arises of whether the optimization for formaldehyde can have a negative impact on the adsorption of other gases. To address this question, the clean air delivery rate (CADR) of an air cleaner was determined for different test gases with either a standard AC filter or an AC filter modified for improved formaldehyde adsorption. Although the modified AC filter performed substantially better for formaldehyde, a strong reduction in the CADR was observed for toluene and nitrogen dioxide. This is a drawback for situations in which these gases are more problematic than formaldehyde. The findings suggest using either specialized filters for different applications or blends of different adsorbants to find the best compromise for the most relevant pollutants.

Voice use of nurses working in the intensive care unit during the COVID-19 pandemic

ObjectiveThis study aimed to investigate the voice use of nurses working in intensive care units (ICUs) and their perception of acoustic environments. Setting and sampleThe research was conducted in four different hospitals in China during the COVID-19 pandemic. A total of 60 ICU nurses were recruited for their voice use monitoring and 100 nurses participated in the survey. Research methodologyFirstly, voice-related parameters such as voice level (SPL, dB), fundamental frequency (F0, Hz), and voicing time percentage (Dt, %) were measured using a vocal monitor. To collect data, a non-invasive accelerometer was attached to the participants' necks during their working hours. Secondly, the perception of the ICU acoustic environment was assessed using semantic differential. ResultsThe results showed that nurses spoke approximately 0.9–4 dB louder to patients and colleagues in ICUs compared to quiet rooms, and their fundamental frequency (F0) significantly increased during work. The voice levels of nurses were influenced by background noise levels, with a significant correlation coefficient of 0.44 (p < 0.01). Furthermore, the background noise levels ranged from 58.1 to 73.9 dBA, exceeding the guideline values set by the World Health Organisation (WHO). The semantic differential analysis identified ‘Stress’ and ‘Irritation’ as the two main components, indicating the prevalence of negative experiences within ICUs. Implications for clinical practiceThis study highlights the potential risk of voice disorders among ICU nurses. The findings also underscore the importance of implementing strategies to reduce noise levels in ICUs to reduce voice disorders among nurses.

Potential ecological risk from heavy metals in surface sediment of lotic systems in central region Peru

High Andean rivers are fragile ecosystems in the face of various threats, including heavy metal contamination. The objective of this study was to evaluate the potential ecological risk of heavy metals in surface sediment of lotic systems in the central region of Peru. Composite samples of surface sediments were collected from the Chía and Miraflores rivers and the concentrations of heavy metals were determined. The ecological risk analysis was carried out based on the contamination indexes and confirmed by the modified degree of contamination (mCd). The concentration of heavy metals in the sediment of the Chía river was in the following descending order: Fe &amp;gt; Mn &amp;gt; Zn &amp;gt; V &amp;gt; Pb &amp;gt; Cr &amp;gt; Ni &amp;gt; Cu &amp;gt; Mo &amp;gt; Hg, y en el río Miraflores fue: Fe &amp;gt; Mn &amp;gt; Zn &amp;gt; Ni &amp;gt; V &amp;gt; Cr &amp;gt; Cu &amp;gt; Pb &amp;gt; Hg &amp;gt; Mo. The mean concentration of Cu, Cr, Fe, Mn, Mo, Ni, Pb, and V in the sediment samples in both rivers did not exceed the threshold values of the continental crust concentration, nor the interim sediment quality guidelines of the Canadian Council of Ministers of the Environment. However, the mean concentration of Hg exceeded the guideline values in the Miraflores river and the likely effect (0.7 mg.kg−1) adverse effects. The values of the enrichment factor (EF), contamination factor (CF), geoaccumulation index (Igeo), and pollution load index (PLI) indicated low contamination in the sediments of the rivers studied, being confirmed by the modified degree of contamination (mCd). Finally, the risk assessment showed that heavy metals in the sediments presented a low potential ecological risk.

Greenhouse gas emissions and their trends over the last 3 decades across Africa

Abstract. A key goal of the Paris Agreement (PA) is to reach net-zero greenhouse gas (GHG) emissions by 2050 globally, which requires mitigation efforts from all countries. Africa's rapidly growing population and gross domestic product (GDP) make this continent important for GHG emission trends. In this paper, we study the emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in Africa over 3 decades (1990–2018). We compare bottom-up (BU) approaches, including United Nations Convention Framework on Climate Change (UNFCCC) national inventories, FAO, PRIMAP-hist, process-based ecosystem models for CO2 fluxes in the land use, land use change and forestry (LULUCF) sector and global atmospheric inversions. For inversions, we applied different methods to separate anthropogenic CH4 emissions. The BU inventories show that, over the decade 2010–2018, fewer than 10 countries represented more than 75 % of African fossil CO2 emissions. With a mean of 1373 Mt CO2 yr−1, total African fossil CO2 emissions over 2010–2018 represent only 4 % of global fossil emissions. However, these emissions grew by +34 % from 1990–1999 to 2000–2009 and by +31 % from 2000–2009 to 2010–2018, which represents more than a doubling in 30 years. This growth rate is more than 2 times faster than the global growth rate of fossil CO2 emissions. The anthropogenic emissions of CH4 grew by 5 % from 1990–1999 to 2000–2009 and by 14.8 % from 2000–2009 to 2010–2018. The N2O emissions grew by 19.5 % from 1990–1999 to 2000–2009 and by 20.8 % from 2000–2009 to 2010–2018. When using the mean of the estimates from UNFCCC reports (including the land use sector) with corrections from outliers, Africa was a mean source of greenhouse gases of 262221863239 Mt CO2 eq. yr−1 from all BU estimates (the subscript and superscript indicate min–max range uncertainties) and of +263717615873 Mt CO2 eq. yr−1 from top-down (TD) methods during their overlap period from 2001 to 2017. Although the mean values are consistent, the range of TD estimates is larger than the one of the BU estimates, indicating that sparse atmospheric observations and transport model errors do not allow us to use inversions to reduce the uncertainty in BU estimates. The main source of uncertainty comes from CO2 fluxes in the LULUCF sector, for which the spread across inversions is larger than 50 %, especially in central Africa. Moreover, estimates from national UNFCCC communications differ widely depending on whether the large sinks in a few countries are corrected to more plausible values using more recent national sources following the methodology of Grassi et al. (2022). The medians of CH4 emissions from inversions based on satellite retrievals and surface station networks are consistent with each other within 2 % at the continental scale. The inversion ensemble also provides consistent estimates of anthropogenic CH4 emissions with BU inventories such as PRIMAP-hist. For N2O, inversions systematically show higher emissions than inventories, on average about 4.5 times more than PRIMAP-hist, either because natural N2O sources cannot be separated accurately from anthropogenic ones in inversions or because BU estimates ignore indirect emissions and underestimate emission factors. Future improvements can be expected thanks to a denser network of monitoring atmospheric concentrations. This study helps to introduce methods to enhance the scope of use of various published datasets and allows us to compute budgets thanks to recombinations of those data products. Our results allow us to understand uncertainty and trends in emissions and removals in a region of the world where few observations exist and where most inventories are based on default IPCC guideline values. The results can therefore serve as a support tool for the Global Stocktake (GST) of the Paris Agreement. The referenced datasets related to the figures are available at https://doi.org/10.5281/zenodo.7347077 (Mostefaoui et al., 2022).

Characterization of Dominant Hydrogeochemical Processes in Groundwater in Onitsha Area, Southeastern Nigeria

The characterization of the dominant hydrogeochemical processes in groundwater in Onitsha area, southeastern Nigeria was carried out. This is to identify the dominant mechanisms responsible for the evolution and the chemical composition of the water sources. A total of fifteen (15) groundwater samples were collected from different locations in the study area in August 2022 and these samples were subjected to chemical analysis using standard methods. The results indicated that the water quality parameters were within the World Health Organization acceptable limits for drinking quality although turbidity in six of the samples exceeded the guideline values. The hydrochemical facies were determined using various plots. Piper diagrams indicated that Ca2+ - Mg2+ - Cl- – SO42- was the dominant facies with Ca2+ and Cl- as the dominant ions. The Durov diagram indicate recharge water in limestone and sandstone aquifers and influenced by important ion exchange reactions. However, the Gibbs plots mainly plotted in the rock dominance zone indicating that the major processes controlling water chemistry in the study area were water-rock interaction and dissolution of rock minerals. The ionic ratio plots were employed to determine the mechanisms and reactions prevalent in the study area that influenced the water chemistry. Na/Cl plot indicated that the excess of Cl- over Na+ was balanced by Ca2+ and Mg2+ while the depletion of Na+ with respect to Clindicated ion exchange reaction which could be attributed to silicate weathering confirming the Na/Cl plot conclusions. The relative abundance of anionic facies shows that Cl- + SO42- were more abundant than HCO3- and the plot of Ca2+ + Mg2+ ions against HCO3- ions depict samples with excess Ca2+ + Mg2+. However, Ca2+ +Mg/HCO3 ratio was less than one (&lt;1) and indicated fresh recharge water.

Trace metals in commercial seafood products (canned, pickled and smoked): Comparison, exposure and health risk assessment

This study used inductively coupled plasma and mass spectrometry, followed by microwave digestion, to assess the concentration of six trace metals (Cr, Ni, As, Cd, Hg, and Pb) in three canned products (tuna in oil [TIO], sardine in oil [SIO], and mackerel in oil [MIO]), two pickled products (prawn pickle [PP] and fish pickle [FP]), and one smoked product (masmin) collected from Tuticorin market, southern India. Trace metal (TM) levels in canned, pickled, and smoked fish varied from 0.01 to 1.48, 0.009 to 0.94, and 0.08 to 4.13 mg/kg, respectively. The concentration of TMs in the seafood was observed in the following order: As > Cr > Pb > Ni > Cd > Hg. Regarding their accumulation in the seafood products, masmin showed the highest levels followed by SIO, MIO, TIO, FP, and PP. The results revealed that smoked products showed higher TM concentrations, followed by canned and pickled products. The level of TMs in seafood products was below the maximum residue limit set by the European Commission (EC/1881/2006) and the Food Safety and Standards Authority of India (FSSAI). Risk assessment for consumer health implied that the evaluated target hazard quotient (THQ < 1), hazard index (HI < 1), and target cancer risk (TCR < 1.E−04) values did not exceed their guideline values and did not cause non-carcinogenic and carcinogenic health impacts through seafood product consumption. The pollution index (Pi) values of TMs in seafood products ranged from 0.01 to 0.7, with As and Cd showing the lowest and highest values, which were below 0.7, indicating their safety for consumption. The metal pollution index (MPI) for TMs in seafood ranged from 9.E−05 to 0.007, with the lowest and highest values associated with PP and TIO products. The MPI value for seafood products was below 1, signifying low TMs accumulation, suggesting the safety of seafood for consumption. The maximum seafood meal consumption limit (CRmm) was calculated, showing that adults can safely consume > 16 meals/month without chronic or acute toxicity. The results of this study suggest that the accumulation of TMs in the analyzed seafood product was below the health guidelines and pollution index values, making it suitable for smooth domestic and international export as well as safe consumption.

A robust method for the determination of lead in water samples using flow injection hydride generation atomic absorption spectrometry

Flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) is a sensitive technique for the quantification of trace amounts of lead. However, plumbane generation is not straightforward and usually HG methods for lead are not robust enough for routine analysis. The optimum pH range for Pb HG is very narrow, so strict control of the acidity of the reaction medium is required for reliable results and in some cases even acid concentrations used for sample preservation can interfere. Moreover, some elements, like Cu, can interfere in the HG reaction suppressing the Pb signal. In this paper we report the development and validation of a method for the determination of Pb in water samples that is robust towards acidity and Cu levels usually found in water samples.All hydride generation parameters were optimized, but special emphasis was put on robustness. The use of borate as a buffer significantly improved the robustness of the method towards acidity, compared to the typical non-buffered HG. Furthermore, the interference of Cu, Sb and Sn in the HG reaction was overcome using thiocyanate as a masking agent. Other elements do not interfere at levels typically found in water samples. The limit of quantification achieved (0.9 μg L−1) is below the current guideline value for Pb in drinking water (10 μg L−1). The linearity of the method was verified between the LOQ and up to 15 μg L−1. An analytical frequency of 25 samples per hour with 3 measurement replicates each was achieved. The method was applied to the analysis of 50 water samples. The concentrations found ranged from <LOD (0.3 μg L−1) and up to 88.8 μg L−1.The proposed method is robust, cost-effective, easily automated and does not require unconventional or expensive equipment. It can be applied for routine analysis of different types of water samples.

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.

Variation in Resource Supply of Mortuary for Autopsy at Tertiary Care Center - A Nation-Wide Survey

Mortuaries and medicolegal services are essential support services to the administration of healthcare. There is a lack of information and uniformity regarding various resource supplies especially day to day consumables for medico-legal services in India. For this reason, a study was undertaken to evaluate the current status of mortuaries and resource supplies for autopsy work as well as the elements that contribute to it. A cross sectional study was conducted in several Indian tertiary care facilities using both qualitative and quantitative methods of data analysis. 74 faculty members from 71 institutes, including 5 AIIMS and AFMC Pune, participated in this study using data from 61 districts across 19 states and the union territories. Information about these health care institutions was gathered using a Google form that included 18 carefully crafted questions with options to observe and interview the faculties who are directly related to autopsy work. Across all the health care facilities we looked and discovered a wide range in resource availability and reluctance on the part of the institute to provide various resources for postmortem services. Polythene and cloth to wrap the body after the postmortem were arranged by relatives and NGOs in 34% and 46% of institutes, respectively; even in 14% of institutes, containers for the preservation of viscera have been arranged by relatives of the deceased. In 57% of institutes, doctors and 45% of institute mortuary workers are not receiving any postmortem allowance; in 30% of institutes, doctors received less than 500 rupees; and in 22% of institute mortuary workers received less than 50 rupees. In 39% of institutes, mortuary workers are outsourced by the institute on a temporary basis, and in 24% of institutes, departmental sweepers are employed as mortuary workers. Most mortuaries did not have adequate and trained human resources. Thus the present study attempts to highlight the variation of resource supply for medico-legal cases in autopsy block, mortuary workers, their recruitment method, and the lowest rank of investigating officer handling PM, highlights the value of uniform guideline for these services at institute, state or national level.

Nepridržavanje pedijatara primarne zdravstvene zaštite u Srbiji najnovijih upustava za lečenje akutnog i hroničnog kašlja kod dece

Introduction: Cough is the most frequent symptom in children and can indicate various pathological conditions. Several international guidelines have been published with a purpose of standardizing and improving the assessment and management of cough. Non-adherence to guidelines often leads to a suboptimal quality of patient care. Our aim was to investigate the adherence of Serbian primary care pediatricians to the latest international guidelines on cough diagnosis and management. Methods: The study included pediatricians working in primary health care centers in Serbia. They were given a questionnaire designed by a team of pediatric pulmonologists which included questions about the choice of diagnostic and therapeutic approaches in acute and chronic cough. Results: Most of primary care pediatricians assessed the value of international guidelines as fair. However, nearly 70% stated that they prescribed herbal syrup for acute cough. Chronic cough is treated mostly with ivy extract, bronchodilators and antihistamines. A majority of doctors declared positive opinion of herbal medicaments and negative opinion of alternative medicine. About 73% stated that they did not use the chest x-ray as a part of diagnostic procedure. Conclusion: Serbian pediatricians do not adhere to international guidelines in relation to diagnosis and treatment of cough. The reasons for non-adherence to guidelines should be further investigated.

Hydro-chemical characteristics and groundwater quality evaluation in south-western region of Bangladesh: A GIS-based approach and multivariate analyses

The study focuses on the chemistry of groundwater and if it is suitable for drinking and for use in agriculture using water quality indices, GIS mapping, and multivariate analyses in Sharsa Upazila, Jashore district, Bangladesh. In this study, the concentration of NH4+, K+, Ca2+, EC, Turbidity overstep BDWS drinking standards in 69 %, 14 %, 100 %, 40 % (WHO), 73 % of samples respectively. The value of Water Quality Indices (WQI) results inferred that the maximum specimen was held good quality for drinking uses, and the values distributed central eastern part to the south-eastern part were good quality water in the selected studied area. The study area's PH, EC, SAR, Na (%), TH, and NO3− values were mapped using GIS tools to show their spatial distribution. The cluster and correlation matrix analyses are used to validate for Principle Component Analysis (PCA). The five PCA results exhibited that the presence of EC, turbidity, K+, SO42− and NO3− was significant and was caused by both geogenic (rock weathering and cation exchange) and anthropogenic (agrochemicals, animal feedback) factor. According to the hydro-geochemical data, the maximum number of samples is of the Ca–Mg–HCO3–Cl type and is dominated by rocks. The irrigation water indices like MH, KR, SAR, and %Na indicate show high-quality groundwater for irrigation purposes. Most of the samples were satisfactory and compiled with WHO and Bangladeshi criteria for standard drinking water guideline values.

Local electrochemical sample acidification for the detection of Pb2+ traces.

Electrochemical detection of pollutants (e.g. heavy metals) in real samples often requires the adjustment of pH to allow optimal sensitivity. Such sample pretreatment can be challenging for on-site applications as it implies the use of valves, pumps and storage of base or acid solutions. We report here the use of an electrochemical approach for the control of water sample pH. It offers the possibility for local pH adjustment while simultaneously detecting Pb2+, whose detection sensitivity is pH dependent. An effective electrochemical method through local electrochemical acidification is performed to detect Pb2+ within a desired pH range without the need to add chemical reagents. Local acidification is based on water electrolysis. An anodic potential is applied to an acidifier to rapidly electrogenerate protons. This allows the sample pH to be tailored to the optimal detection condition. Reduction of the Pt oxide layer formed on the acidifier is key to obtain repeatable results in Pb2+ detection. On-site sample acidification is combined with anodic stripping voltammetry to reach a detection limit of 6 ppb (30 nM), which is lower than the World Health Organization guideline value for Pb2+ level in drinking water.

Проблема изложения требований норм в области пожарной безопасности в России

Purpose. The analysis of regulatory documents and scientific publications is presented, describing the discharge parameters of automatic fire extinguishing installations, as well as criteria for their design. The analysis is presented in chronological order of the documents' editions. In compliance with the requirements of regulatory documents in the field of fire safety, facilities under protection are provided with automatic fire extinguishing installations (AFEI). The currently valid regulatory documents do not specify the fire load, according to which groups of premises are classified and types and methods of fire extinguishing agents discharge are determined. The above mentioned makes it necessary to analyze the regulatory and scientific literature with the objective of further defining a unified methodology for designing automatic fire extinguishing installations. Methods. The authors have carried out a chronological analysis of special literature in order to identify the stages of AFEI discharge parameters development. All types of fire extinguishing installations, which are subject to the requirements of regulatory documents, have been studied. Findings. Based upon the outcomes of the study in question, it is possible to make a conclusion that at present the regulatory documents governing the requirements for automatic fire extinguishing installations lack current data on modern substances and materials, and therefore the methods described in this paper may be inaccurate and sometimes crucial when determining AFEI characteristics. Research application field. The outcomes of the given research may be used by: – scientific institutions within various structures and departments as the base for development of guideline values of fire load as well as requirements to AFEI working conditions; – educational institutions within various structures and departments in the course of teaching and learning activities; – manufacturers producing fire equipment intended to provide fire safety at the protected facilities of various purposes. Conclusions. The given problem may be solved be means of updating fire load parameters with the help of different software systems, as well as full-scale experiments. This will allow determining the actual fire load parameters and effective characteristics of automatic fire extinguishing installations for modern buildings and premises.

Diagnostic Value of American Thyroid Association Guidelines,American College of Radiology Thyroid Imaging Reporting and Data System,and Chinese Thyroid Imaging Reporting and Data System Alone and Combined With BRAFV600E Mutation in Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance

Objective To explore the diagnostic efficacy of American Thyroid Association(ATA)guidelines,American College of Radiology Thyroid Imaging Report and Data System(ACR-TIRADS),and Chinese Thyroid Imaging Reporting and Data System(C-TIRADS)alone and combined with BRAFV600E mutation in atypia of undetermined significance/follicular lesion of undetermined significance(AUS/FLUS).Methods A total of 138 patients who underwent ultrasound-guided fine needle aspiration(FNA)in the Chinese PLA General Hospital from January 2020 to May 2023 were selected.The clinicopathological and ultrasound characteristics were retrospectively analyzed for each nodule.Each nodule underwent preoperative BRAFV600E mutation testing and was diagnosed according to the ATA guidelines,ACR-TIRADS,and C-TIRADS.The diagnostic efficacy of ATA guidelines,ACR-TIRADS,and C-TIRADS alone and combined with BRAFV600E mutation was assessed based on the results of histopathological diagnosis.Results The 138 AUS/FLUS thyroid nodules included 45(32.6%)benign ones and 93(67.4%)malignant ones.The patient age(t=1.444,P=0.151),gender(χ2=0.259,P=0.611),and location of nodules(χ2=2.055,P=0.358)had no statistical significance for the differentiation between benign and malignant nodules,while nodule size(Z=2.500,P=0.012),echo(χ2=14.693,P<0.001),composition(χ2=17.075,P<0.001),aspect ratio ≥1(χ2=9.477,P=0.002),and microcalcification(χ2=6.892,P=0.009)were of significance for the differentiation.When applied alone,BRAFV600E mutation showed high specificity(95.56%)and positive predictive value(95.65%).Among the three ultrasound grading systems,ACR-TIRADS had the highest sensitivity(χ2=37.923,P<0.001;χ2=40.462,P<0.001)and accuracy(χ2=81.595,P<0.001;χ2=76.912,P<0.001),while C-TIRADS had the highest specificity(χ2=11.746,P<0.001;χ2=21.235,P<0.001).However,the three systems showed no statistically significant difference in the diagnostic efficiency when applied alone(Z=1.177,P=0.239;Z=0.213,P=0.831;Z=1.016,P=0.310).The combination of BRAFV600E mutation with ACR-TIRADS or C-TIRADS improved the diagnostic efficacy of BRAFV600E mutation in distinguishing the benign and malignant AUS/FLUS nodules(Z=2.107,P=0.035;Z=2.752,P=0.006).The combination of ATA guidelines with BRAFV600E mutation increased the diagnostic accuracy of BRAFV600E mutation(χ2=20.679,P<0.001),while it had no statistically significant difference in distinguishing the benign and malignant AUS/FLUS nodules(Z=1.321,P=0.186).The combination of ATA guidelines,ACR-TIRADS,or C-TIRADS with BRAFV600E mutation improved the diagnostic efficacy of ultrasound grading systems for AUS/FLUS nodules(Z=2.770,P=0.006;Z=2.770,P=0.006;Z=2.890,P=0.004).Specifically,ACR-TIRADS combined with BRAFV600E mutation showed the highest sensitivity(χ2=4.712,P=0.030;χ2=4.712,P=0.030),while C-TIRADS combined with BRAFV600E mutation showed the highest accuracy(χ2=77.627,P<0.001;χ2=85.827,P<0.001).However,there were no statistically significant differences in diagnostic performance between the combinations(Z=1.276,P=0.202;Z=0.808,P=0.419;Z=1.615,P=0.106).Conclusion ATA guidelines,ACR-TIRADS,and C-TIRADS combined with BRAFV600E mutation can improve the diagnostic efficacy of BRAFV600E mutation or ultrasound grading system alone in AUS/FLUS nodules,which can facilitate the further management and treatment of such patients.

Identifying the source and fate of boron in geothermal water: Evidence from B/Na and B isotopes

High level dissolved B, which poses risks to human health, has been widely observed in geothermal water. In the Guide Basin, NW China, a series of geothermal water samples along a fault show a wide range of B contents ranging from 3.14 to 8.33 mg/L, which are higher than the WHO Guideline value equaling 2.4 mg/L in drinking water. To identify the sources and fate of B, we conduct a comprehensive analysis of hydrochemistry and stable isotopes (D, 18O and 11B) of three thermal fields representing three stages of hydrogeochemical evolution (stages I, II and III). From stage I to III, there are trends of increasing mineral dissolution, which is supported by increasing mean reservoir temperature and concentrations of conservative elements (Cl, Na, K, Li and Si). Geothermal water in stage I with meteoric origin and the lowest reservoir temperature has the highest B/Na resulting from silicate dissolution and falls on the mixing line between granitoids and cold water on the plot of δ11B versus 1/B, showing the control of silicate dissolution. However, geothermal water in stage III has lower Ca, B Sr and B/Na than that in stage II. Because of the occurrence of other processes, geothermal water in stages II and III deviates from the LMWL. Compared with geothermal water in stage I, the increased Sr/Ca and decreased B/Ca show that B are removed by both coprecipitation and vapor separation. With the aid of B isotopes, we find vapor separation dominates in stage II, whereas carbonate precipitation dominates in stage III. Overall, a combined use of three isotopes (H, O and B) and three element ratios (B/Na, B/Ca and Sr/Ca) leads to a complete understanding of B cycle and hydrogeochemical evolution in hydrothermal systems.

Beneficial and adverse effects of dam construction in canal tannery wastewater effluent with a high content of chromium in Hazaribagh, Bangladesh

BackgroundBlockage to divide downstream canals into upstream canals, into which tannery wastewater including a high concentration of trivalent chromium [Cr(III)] is directly discharged, has been constructed in Hazaribagh, a tannery built-up area in Bangladesh. However, there has been no study to verify the environmental significance of blockage construction for water pollution of Cr in nature. MethodsConsecutive fixed area monitoring for a total of 164 water samples collected outside and inside Hazaribagh from 2014 to 2023 was carried out to clarify the effects of stagnant and flowable canal water in the presence or absence of blockage on Cr(III) and hexavalent Cr [Cr(VI)] concentrations. ResultsSince pollution of Cr(III) and Cr(VI) in Buriganga River (outside Hazaribagh) was not serious, this study then focused on their pollution in canal water (inside Hazaribagh) in the nonblockage period, blockage construction period and blockage destruction period. As expected, the mean Cr(III) concentration in downstream canal water samples in the blockage construction period was more than 98% lower than that in the upstream canal water samples in the same period, while the concentrations were comparable in downstream and upstream canal water samples in the nonblockage period and blockage destruction period. Unexpectedly, the mean concentration of Cr(VI) in the upstream canal water samples in the blockage construction period was 38.6-fold and 3.3-fold higher than that in the downstream canal water samples and the Cr(VI) guideline value by the US-EPA, respectively. ConclusionThis study demonstrated for the first time not only a merit of decreased Cr(III) pollution but also a demerit of increased Cr(VI) pollution in stagnant water derived from blockage construction in natural environments. This bitter lesson obtained by the enclosure of Cr(III)-polluted water is globally applicable for water pollution of Cr(III), which is used in various industries including the leather industry.