Permissible Levels Research Articles

Phenomenon of ignition and explosion of high-entropy alloys of systems Ti-Zr-Hf-Ni-Cu, Ti-Zr-Hf-Ni-Cu-Co under quasi-static compression

The phenomenon of ignition and explosive failure of specimens from high-entropy alloys (HEAs) of systems Ti-Zr-Hf-Ni-Cu, Ti-Zr-Hf-Ni-Cu-Co at quasi-static compression tests was found. It physical model is proposed. It is exhibited that the reason for this phenomenon is the release of energy of the oxidation reaction; such reaction is initiated due to the heat released ahead of the shear crack tip at brittle fracture of the specimens under quasi-static compression. It is shown that ignition and failure by explosion are the specific features of brittle fracture for high-entropy alloys containing Ti-Zr-Hf, in general. This phenomenon is realised when certain critical levels of strength and ductility of these alloys are reached. The importance of these critical levels of strength and ductility lies in the fact that they predetermine the maximum permissible level of strength and brittleness for this class of HEAs, above which they lose their structural and functional properties, turning to the energetic alloys capable of explosive release of a significant amount of thermal energy. This specific feature of the high-entropy alloys containing Ti-Zr-Hf outlines the scope of their application and defines the boundary separating structural and functional high-entropy alloys from energetic high-entropy alloys.

Temporal trends of risks in consumption of wild and farmed mussels in 2013–2019 in the Saldanha Bay area (South Africa)

The levels of 24 macro- and microelements in mussels were determined by the instrumental neutron activation analysis. The samples were collected during the period of 2013–2019 on three sites with different natural features in the Saldanha Bay area. The safety of mussel consumption was calculated using several different approaches: considering maximum permissible levels for seafood, maximum tolerable consumption rates, target hazard quotients and hazard indices. In general, the wild and farmed mussels demonstrated low levels of risk for human health during the entire studied period, except for intakes of such elements as Fe and Zn in several cases. Based on the applied approaches, Cr, Fe, Ni, Zn, As and I in wild mussels can pose possible health risks to potential consumers in several cases during 2013–2019. It was concluded that the safe level of weekly consumption rate should be less than 100 g/week per person, according to the highest calculated values of concentrations. Possible symptoms of deficiency and excess of elements and their levels and significance for human health are considered. The content of wild and farmed mussels from the Saldanha Bay is influenced by the seasonal natural and anthropogenic factors, including sea disturbance, coastal runoff, and harbor traffic.

Elevated Uptake and Translocation Patterns of Heavy Metals in Different Food Plants Parts and Their Impacts on Human Health.

Irrigation with contaminated wastewater is a common practice in cultivation of crops and vegetables in many developing countries due to the scarcity of available fresh water. The present study has investigated the transfer and mobilization trends of heavy metals in different crops and vegetables plants grown in contaminated soil and waterbody. The translocation patterns of metals from polluted sources into different organs of plants bodies such as roots and edible parts and associated health risks have been evaluated simultaneously. Total of 180 different environmental samples including food plants, agricultural soil, and irrigation water were collected and analyzed. Heavy metal concentrations (Fe, Ni, Mn, Pb, Cu, Cd, As) in water, soil, and different parts of crops and vegetable plants were compared with the permissible levels reported by FAO/WHO, EU, and USEPA. Different metals contents within the food plants were found to be in the order of Fe > Mn > Ni > Cu > Pb > Cd > As. Pollution load index (PLI) data indicate that soil is highly polluted with Cd as well as moderately contaminated by As and Cu. Bioconcentration factor (BCF) analysis showed excessive accumulation of some heavy metals in crops and vegetables. Target hazard quotient (THQ) and target carcinogenic risk (TCR) analysis data showed higher carcinogenic and non-carcinogenic risks for both adult and children from the consumption of metal-contaminated food items. The results of metal pollution index (MPI), estimated daily intake (EDI), and hazard index (HI) analyses demonstrated the patterns of metals pollution in different food plants.

Analysis of heavy metals and pathogen levels in vegetables cultivated using selected water bodies in urban areas of the Greater Accra Metropolis of Ghana

Open-surfaced water sources have been used to irrigate vegetable farms in cities. Open-surface water often contains unmonitored concentrations of health-threatening contaminants that pose health risks, especially when used to produce vegetables for human consumption. However, information on levels of heavy metals and faecal coliform bacteria in such vegetables in selected sites, especially in Greater Accra Metropolitan Area (GAMA) of Ghana is rare. This study examines the levels of heavy metals and faecal coliform in two vegetables-lettuce and bell pepper - that were cultivated using open-surface wastewater from drains and constructed reservoirs at different locations of the GAMA. Using concurrent mixed methods, questionnaires were administered to 67 vegetable farmers, followed by the collection of vegetable samples from three urban farm sites, Haatso and Dzorwulu and Weija irrigation scheme site (WISS) for laboratory analysis. The concentrations of Lead (Pb), Mercury (Hg) and Cadmium (Cd) were determined using atomic absorption spectroscopy after microwave digestion of the vegetables while total faecal coliform was quantified using MacConkey-Endo broth method. The results from all three sites showed that the concentrations of Cd (=0.001 μg/mg) and Pb (=0.005 μg/mg) in lettuce were within the World Health Organization's (WHO) permissible levels. However, the Hg (≥0.309 μg/mg) and faecal coliform (>5 count/100 ml) in the vegetables from all three sites exceeded the WHO permissible limits. Therefore, consumers of vegetables from such urban farms are exposed to health risks associated with Hg and faecal coliforms. There is the need to intensify education on the health risks of consuming vegetables produced from open-surface water sources from the observed sites. The enforcement of existing phytosanitary standards to enhance food safety and the quality of urban vegetables is also recommended.

Assessment of ecological and health risk impact of heavy metals contamination in stream sediments in Itapaji-Ekiti, SW Nigeria

BackgroundHeavy metal contamination in aquatic ecosystems is a major environmental and health concern globally. This study assessed the ecological and health risks associated with heavy metal pollution in stream sediments in Itapaji-Ekiti, Southwest Nigeria. The study contributes collectively to a comprehensive understanding of the geochemical dynamics and contamination factors affecting the studied stream sediments. MethodsHeavy metals study was conducted on stream sediments within the geographical confines of sheet 244, Ado map. Seventeen stream sediment samples were obtained from various sites and subjected to analysis to determine the concentrations of heavy metals such as lead (Pb), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), barium (Ba), arsenic (As), nickel (Ni) and vanadium (V) using X-ray Fluorescence (XRF). The results showed that the concentrations of these metals exceeded permissible levels at most sampling sites, indicating significant contamination of the stream sediments. The concentrations and pollution levels of the heavy metals from selected sampling sites were documented for ecological and health risk evaluations. ResultThe findings revealed that the concentrations of these metals surpassed acceptable thresholds at the majority of sampling locations, indicating significant contamination of the stream sediments. The concentrations of heavy metals, specifically Cr and Cd, exhibit moderate contamination, while Pb and Ba demonstrates a significant contamination factor with moderate to extreme degree of contamination. Several ecological risk indices were calculated to evaluate the potential ecological risks. The results revealed that the stream sediments posed considerable to very high ecological risks at most sites based on the risk quotient, contamination factor and pollution load index. The non-carcinogenic and carcinogenic risk assessments for heavy metals in stream sediments exposed potential health risks, especially for children, indicating the need for protective measures. The cumulative cancer risk, particularly for adults, raised concerns about the overall health implications of prolonged exposure to the heavy metal concentrations in the streams. ConclusionThe study also evaluated ecological and health risks, revealing potential risks from heavy metals. Hazard and cancer risk assessments suggested the increasing potential of heavy metals to pose health risks, particularly for inhabitants of the area.

Comparative Analysis of Histamine in Fresh and Processed Fish Sold in Jordanian Market

Food poisoning from histamine, a biogenic amine formed due to the decarboxylation of histidine by bacteria in fish and fish products, has become a pivotal concern in food safety. This study measured the concentration of histamine in various fish products available in the Jordanian market, but manufactured in multiple countries, utilizing an Enzyme-Linked Immunosorbent Assay (ELISA). The ELISA kit and the protocol were provided by Veratox for histamine. Approximately 93.69% of the samples tested positive for the presence of histamine, with levels ranging between 0.317 and 230.41 mg/kg. Solely 0.9% of the samples exceeded the maximum permissible level established by the European Union (EU) and only 4.5% of the fish samples were free of histamine. The Principal Component Analysis (PCA) revealed that the type of fish was the most significant source of variability in histamine concentration, explaining 31.2% of the variability. Conversely, the sample weight accounted for the least variability (only 20.2%), implying that it has little or no effect on the concentration of histamine in the fish samples.

Physico-Chemical Quality Assessment of Ground Water in Kathmandu Valley and Siraha District

A key element in maintaining human health is the quality of drinking water which is a vital component of natural resources. This study was conducted to assess the ground water quality in the Kathmandu Valley and Siraha district from October 2022 to March 2023 in the Water Engineering and Training Centre, Ratopul, Kathmandu. A total of 123 water samples were collected from various wells and borings around the Kathmandu Valley and Siraha district and were subjected to physicochemical investigation following the standard techniques for water sample collection and analyzed by methods as described in the American Public Health Association (1998). The pH, conductivity, turbidity, ammonia concentration, and iron content were found to exceed National Drinking Water Quality Standard guidelines value in 21.95%, 3.25 %, 53.65 %, 47.15 %, and 18.7 % of total water samples respectively. All water samples had total hardness and chloride levels within the acceptable range. The arsenic content of all samples except one well water sample from Siraha was found within a permissible level. The findings suggest that water quality is not satisfactory, which could lead to various water-borne illnesses. Therefore, proper water purification techniques should be used before consumption.

Soil Contamination and Biomarkers in Ucides cordatus in Mangroves from Baía de Todos os Santos, Bahia, Brazil

The aim of the present study was to analyze the response to exposure to pollutants (trace elements and organic pollutants) using biomarkers (micronucleated cells and glutathione S-transferase and catalase activity) in uçá crab Ucides cordatus. The study was carried out at four sites: Cacha Prego (CP) and Ponta Grossa (PG), areas with low anthropic activity; and Ilha de Maré (IM) and Pitinga (PT), areas affected by industrial activity. At each site, soil and crab samples were collected to analyze the contents of potentially toxic elements (total concentration and chemical partitioning of trace elements), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). Both total concentrations and geochemical fractions of Cu, Zn, and Ni in soils were significantly higher in IM. Likewise, higher reactive Pb contents were observed in mangroves both in IM and in PG. Values above quality limits were observed for organic pollutants (PAHs) in soils from CP and PT, while PCB contents were below the maximum permissible levels. Metals in crabs also showed spatial variations, with higher Cu concentrations in all tissues in IM and PT and higher Ni concentrations in hepatopancreas in PT during the dry season. PAH values in crabs did not show spatial variations; however, crustaceans with contents above maximum limits in their muscle tissue were found in CP. Crabs from the Baia de Todos Santos showed different responses in biomarker expression, with higher enzymatic activity and greater numbers of micronucleated cells in crabs from IM, suggesting oxidative stress and genotoxicity in this mangrove forest.

Sustainable Production of Carboxymethyl Cellulose: A Biopolymer Alternative from Sugarcane (Saccharum officinarum L.) Leaves

This study explores the potential of sugarcane (Saccharum officinarum L.) leaves (SCLs), a significant agricultural waste, for the sustainable production of carboxymethyl cellulose (CMC) utilizing an innovative approach of carboxymethylation with monochloroacetic acid and varying sodium hydroxide (NaOH) concentrations (ranging from 20 to 60 g/100 mL). The optimal carboxymethylation condition was identified as 40 g/100 mL NaOH, which yielded the highest degree of substitution (DS = 0.86). Furthermore, a higher ash content in the obtained CMC indicated significant carboxymethyl substitution within the structure. The chemical structure of cellulose and the resulting polymers were characterized using Fourier transform infrared spectroscopy (FTIR). The FTIR spectrum exhibited characteristic peaks of carboxymethyl groups and their salts at wavenumbers of 1588–1591 cm−1 and 1413–1415 cm−1, respectively. The analyses from X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) revealed detailed insights into the crystallinity and morphology of carboxymethyl cellulose (CMC). The levels of heavy metals, including arsenic, lead, cadmium, and mercury, in the purified CMC were assessed using inductively coupled plasma mass spectrometry (ICP-MS) and were found to be within the recommended WHO/FAO limits, except for lead, which exceeded permissible levels. The prepared CMC demonstrated high purity at 99.34%, surpassing the 98.00% purity requirement for commercial-grade CMC. This product exhibits strong potential for diverse industrial applications, including paper coating, textile sizing and printing, ceramic glazing, and various uses in the oil industry.

LITEC: An experimental facility for the validation of the IFMIF-DONES Impurity Control System

The Impurity Control System (ICS) of IFMIF-DONES is devoted to assuring lithium purity. After its circulation through the target, some undesired products will contaminate the lithium: deuterium, hydrogen, tritium, and beryllium. In addition, due to the high velocity of the flowing lithium, the target assembly, piping system, and other auxiliaries are subjected to a significant corrosion rate, thus leading also to the presence of metallic impurities in the liquid lithium (iron, nickel, molybdenum…). Finally, nitrogen, oxygen, and carbon will also be present.These impurities may compromise the operation of the facility: they may enhance the erosion/corrosion effect, shortening the operational life of equipment; they may be activated having an important impact on safety strategy, maintenance, and operational procedures; finally, the erosion caused to the target nozzle may produce fluid perturbations affecting to different aspects: fluid-dynamics, cavitation, and thermo-mechanics.The ICS extracts a fraction of the liquid from the DONES main lithium loop to be purified in dedicated traps, to maintain impurities below permissible levels to achieve the required safety and operational conditions.The validation of the ICS at a relevant circuit size will be performed in a new experimental facility called LITEC (The LIthium TEchnologies CIEMAT loop). It consists of a forced circulation lithium circuit. An electromagnetic pump provides a wide operational range for testing all the purification systems envisioned in the ICS. It has four test sections, where trap prototypes will be installed. An injection system also foresees the possibility of introducing impurities to simulate realistic IFMIF-DONES conditions. Finally, a specific branch will monitor online and offline the impurities.LITEC will contribute significantly to clarifying key aspects of the design and operation of IFMIF-DONES lithium systems and will be a reference facility for research activities in lithium technologies. In this work, its engineering design, operational parameters, and characteristics are presented.

Through bond energy transfer (TBET)-based chemosensor with large Stokes shift for colorimetric and fluorogenic determination of Fe3+ in aqueous system and intracellular imaging application

Chemosensor based on through-bond energy transfer (TBET) mechanism with triazaborolopyridinium (TBP) fluorophore as energy donor and rhodamine fluorophore as energy acceptor was designed, and its Fe3+ ion sensing properties were investigated in aqueous media. Prominent change of solution from yellow to pink and turn-on fluorescence emission was realized by employing Fe3+ selective recognition to form a Fe3+-rhodamine conjugate giving rise to emission at 590 nm with a large Stokes shift (210 nm) under the excitation at 380 nm. This sensor was highly selective and sensitive for distinguishing Fe3+ ions from other common cations. Interestingly, the achieved chemosensor exhibits the detection limits of 32 ppb and 14 ppb for chromogenic and fluorometric analysis, respectively, which are lower than the WHO and U.S. EPA permissible levels in drinking water. The reversible behavior of the Fe3+-sensor complex with the alternate additions of hydrazine and Fe3+ could establish the potential reusability. Moreover, the sensor has also been successfully applied for imaging the presence of Fe3+ ions in living cells.

Оптимизация регулирующих воздействий на основе дифференцированного подхода к управлению качеством атмосферного воздуха и риском здоровью населения

The study focuses on substantiating the most optimal regulatory actions aimed to minimize health risks caused by airborne exposures within Rospotrebnadzor activities including the Clean Air Federal project and the ongoing experiment on setting quotas for emissions. The aim of this study was to comparatively assess effectiveness of regulatory actions as regards specific subjects (exemplified by heat-power engineering objects) with or without use of differentiated approaches to managing ambient air quality and health risks. We analyzed a database on priority sources of ambient air pollution in an analyzed area; performed a hygienic assessment of ambient air quality relying on computed data and also estimated contributions made by specific chemicals and objects to the total pollution; calculated population health risks; implemented an algorithm for substantiating optimal regulatory actions aimed to mitigate health risks under airborne exposures; comparatively analyzed activities stipulated by the Complex plan and suggested optimal regulatory actions identified by solving the optimization task. We conducted a reconnaissance stage-by-stage assessment of effectiveness of air protection activities over 2019–2023 relying on hygienic indicators and risk levels. As a result, we established that implementation of air protection activities and a reduction in total emissions of more than 20 pollutants by heat-power engineering objects would not ensure significant improvement of environmental conditions in the analyzed area considering their share contributions. Safe standards would still be violated in residential areas with levels of chemicals reaching 6.25 single MPL and 7.0 average annual MPL. An optimal sufficient result, considering this share contribution, would be a reduction in emissions from all heat-power engineering objects by 3.47 thousand tons of 10 specific chemicals. This is lower than a reduction planned within the Complex plan on total emission reduction (18.1 thousand tons). To ensure conformity with safe standards that stipulate chemical levels in ambient air and to achieve permissible risk levels, it is necessary to apply a differentiated approach to reductions in emissions (by 1.06 thousand tons overall), which targets specific chemicals, at other sources of ambient air pollution. Use of a differentiated approach to selecting optimal regulatory actions as regards all sources of ambient air pollution considering their share contributions will make it possible to define priority environmental protection activities, adjust the Complex plans and ensure conformity with safe standards and permissible risk levels in all residential areas.

Optimization of regulatory actions based on a differentiated approach to managing ambient air quality and health risks

The study focuses on substantiating the most optimal regulatory actions aimed to minimize health risks caused by airborne exposures within Rospotrebnadzor activities including the Clean Air Federal project and the ongoing experiment on setting quotas for emissions. The aim of this study was to comparatively assess effectiveness of regulatory actions as regards specific subjects (exemplified by heat-power engineering objects) with or without use of differentiated approaches to managing ambient air quality and health risks. We analyzed a database on priority sources of ambient air pollution in an analyzed area; performed a hygienic assessment of ambient air quality relying on computed data and also estimated contributions made by specific chemicals and objects to the total pollution; calculated population health risks; implemented an algorithm for substantiating optimal regulatory actions aimed to mitigate health risks under airborne exposures; comparatively analyzed activities stipulated by the Complex plan and suggested optimal regulatory actions identified by solving the optimization task. We conducted a reconnaissance stage-by-stage assessment of effectiveness of air protection activities over 2019–2023 relying on hygienic indicators and risk levels. As a result, we established that implementation of air protection activities and a reduction in total emissions of more than 20 pollutants by heat-power engineering objects would not ensure significant improvement of environmental conditions in the analyzed area considering their share contributions. Safe standards would still be violated in residential areas with levels of chemicals reaching 6.25 single MPL and 7.0 average annual MPL. An optimal sufficient result, considering this share contribution, would be a reduction in emissions from all heat-power engineering objects by 3.47 thousand tons of 10 specific chemicals. This is lower than a reduction planned within the Complex plan on total emission reduction (18.1 thousand tons). To ensure conformity with safe standards that stipulate chemical levels in ambient air and to achieve permissible risk levels, it is necessary to apply a differentiated approach to reductions in emissions (by 1.06 thousand tons overall), which targets specific chemicals, at other sources of ambient air pollution. Use of a differentiated approach to selecting optimal regulatory actions as regards all sources of ambient air pollution considering their share contributions will make it possible to define priority environmental protection activities, adjust the Complex plans and ensure conformity with safe standards and permissible risk levels in all residential areas

Научное обоснование среднегодовой предельно допустимой концентрации ванадия пентоксида в атмосферном воздухе по критериям допустимого риска

Relevance of this study is determined by the sanitary-epidemiological legislation of the Russian Federation with stipulated requirements to create hygiene standards for environmental factors ensuring their safety for people. These hygienic standards should guarantee absence of impermissible lifetime health risks. Divanadium pentoxide is a chemical that should be mandatorily regulated in ambient air under long-term exposure due to its wide prevalence and high toxicity. An average annual MPL for divanadium pentoxide was established by using systemic analysis of research literature and regulatory documents. According to selection results, three key epidemiological studies were taken for further analysis. They provided evidence of adverse effects produced by divanadium pentoxide on human health (the respiratory organs in particular) under chronic inhalation exposure. When analyzing a study design, we paid special attention to description of observation groups, values of exposure and nature of its effects, adverse health outcomes caused by exposure to divanadium pentoxide as well as to a type and a value of a point of departure. We calculated a value of the total (complex) uncertainty factor in order to establish an average annual maximum permissible level of the analyzed chemical. As a result, we suggest a scientifically substantiated (among other things, as per permissible health risk levels) average annual maximum permissible level for divanadium pentoxide, which equals 0.0001 mg/m3. This level is safe for human health under lifetime exposure. It is noteworthy that this level corresponds to ‘low uncertainty’, which indicates its high safety for human health.

Scientific substantiation of average annual maximum permissible level of vanadium pentoxide in ambient air as per permissible health risk

Relevance of this study is determined by the sanitary-epidemiological legislation of the Russian Federation with stipulated requirements to create hygiene standards for environmental factors ensuring their safety for people. These hygienic standards should guarantee absence of impermissible lifetime health risks. Divanadium pentoxide is a chemical that should be mandatorily regulated in ambient air under long-term exposure due to its wide prevalence and high toxicity. An average annual MPL for divanadium pentoxide was established by using systemic analysis of research literature and regulatory documents. According to selection results, three key epidemiological studies were taken for further analysis. They provided evidence of adverse effects produced by divanadium pentoxide on human health (the respiratory organs in particular) under chronic inhalation exposure. When analyzing a study design, we paid special attention to description of observation groups, values of exposure and nature of its effects, adverse health outcomes caused by exposure to divanadium pentoxide as well as to a type and a value of a point of departure. We calculated a value of the total (complex) uncertainty factor in order to establish an average annual maximum permissible level of the analyzed chemical. As a result, we suggest a scientifically substantiated (among other things, as per permissible health risk levels) average annual maximum permissible level for divanadium pentoxide, which equals 0.0001 mg/m3. This level is safe for human health under lifetime exposure. It is noteworthy that this level corresponds to ‘low uncertainty’, which indicates its high safety for human health.

Smartphone-Facilitated In-Situ Hearing Aid Audiometry for Community-Based Hearing Testing.

Hearing loss prevalence is increasing, with an estimated 2.5 billion people affected globally by 2050. Scalable service delivery models using innovative technologies and task-shifting are World Health Organization priorities to improve access to hearing care, particularly in low- and middle-income countries. Smartphone-facilitated audiometry in the community using hearing aids covered by noise-attenuating ear cups ("in-situ") could support more accessible hearing care when provided by less trained individuals such as community health workers (CHWs). This study aimed to determine the validity of this method for potential hearing aid fitting. Study objectives included determining the maximum permissible ambient noise level (MPANL), inter-device reliability, clinical threshold accuracy, reliability, and performance in real-world settings. Experiment 1: 15 normal-hearing adult participants were evaluated to determine MPANLs for circumaural Peltor 3M earcups covering Lexie Lumen hearing aids with smartphone-facilitated in-situ audiometry. MPANLs were calculated by measuring the difference in attenuation between thresholds obtained with standard headphones and in-situ hearing aids. Experiment 2: Pure-tone frequency and intensity output of 14 same-model Lexie Lumen hearing aids were measured to determine inter-device reliability. Pure-tone stimuli were measured and analyzed to determine sound pressure levels in decibels and pure-tone frequency when connected to a test box 2cc coupler. Experiment 3: 85 adult participants were tested in a sound booth to determine the accuracy of automated in-situ pure-tone audiometry (PTA) compared to clinical PTA (500, 1000, 2000, 3000, 4000, 6000 Hz) facilitated by an audiologist. The first 39 participants were tested twice to determine test-retest reliability. Experiment 4: In a community setting, 144 adult participants were tested with automated in-situ audiometry facilitated by CHWs using a smartphone app. These participants were subsequently tested with automated mobile PTA (500, 1000, 2000, 4000 Hz). An additional 44 participants were tested twice to determine test-retest reliability. Experiment 1: MPANLs of the Peltor 3M earcup-covered hearing aids were higher than standard headphones across all frequencies, ranging from 24 to 47.3 dB SPL. Experiment 2: Inter-device performance reliability was high, with all inter-device differences across all intensities and frequencies less than 3 dB. Frequency output was consistent and differed less than 0.7% between devices. Experiments 3 and 4: 85.2% and 83.3% of automated in-situ audiometry thresholds were within 10 dB of thresholds obtained in the sound booth and in a community setting, respectively. Acceptable test-retest intraclass correlation coefficient (ICC) was evident across all thresholds obtained in a sound booth (ICC = 0.85 to 0.93) and in a community setting (ICC = 0.83 to 0.97). Smartphone-facilitated in-situ audiometry allows for reliable and valid community-based testing. A simple smartphone user interface and automated in-situ audiometry allow CHWs with minimal training to facilitate the testing. With the additional capability to program hearing aids via the smartphone after the initial test, this approach would have the potential to support widespread access to personalized hearing aid fittings facilitated by CHWs in low- and middle-income countries. This approach also supports self-fitting options based on in-situ thresholds, enabling testing and fitting via over the counter hearing aids.

Кластерный подход в изучении рисков здоровью населения, обусловленных контаминацией пищевых продуктов тяжелыми металлами

Food products are a source of energy and essential substances but also of anthropogenic contaminants such as heavy metals. The aim of the study was to assess population health risks posed by contamination of food products with heavy metals, taking into account peculiarities of food preferences. An epidemiological study of actual nutrition of adult population of Samara region was conducted, the sample size was 1,856 people. At the first stage, using factor analysis, respondents' adherence to a certain model of food preferences was established; at the second stage, 5 homogeneous groups (clusters) of people with similar types of nutrition were formed using cluster analysis. The first cluster included individuals with maximum commitment to a high level of consumption of all studied foods; the second cluster was characterized by commitment to consumption of high-calorie foods such as baked goods, confectionery, sausages, potatoes, eggs, and cheese. Individuals from the cluster 3 showed a distinct preference for consumption of vegetables, fruit and dairy products. Individuals from the cluster 4 had no special preferences for any of the studied foods. The fifth cluster included people who had maximum preference for meat and meat products, smoked meats, pickles and salted fish. The content of cadmium, mercury, lead, and arsenic in food products was assessed via atomic absorption and photometric methods. The study relied on using social and hygienic monitoring data from the Samara Regional Rospotrebnadzor (Federal Service for Surveillance on Consumer Rights and Human Wellbeing) collection. Risk assessment of carcinogenic and non-carcinogenic effects was carried out in each of the five formed clusters taking into account modern methodological approaches. It was found that in all food clusters, the hazard coefficients for intake of contaminants in median concentrations and in the 90th percentile did not exceed permissible levels. In all clusters, the endocrine system was most at risk (HI = 1.68 ÷ 1.25). For all clusters, carcinogenic risk (for median concentrations) was created by arsenic both at the individual and the population level. The risk was the highest for people whose diets were characterized by high levels of consumption of high-calorie products. Cluster approach makes it possible to identify the most vulnerable groups of population in terms of risk burden for making managerial decisions and carrying out preventive measures.

Assessment of total aflatoxin and ochratoxin A in poultry feed ingredients by thin-layer chromatography and enzyme-linked immunosorbent assay.

This study was conducted to evaluate the prevalence of total aflatoxin (AF) and ochratoxin A (OTA) in poultry feed ingredients under different environmental conditions during the summer and winter seasons, while the hygiene quality of the feed ingredient was assessed through viable fungal count (VFC). A total of 288 poultry feed ingredients (n = 96 each) samples were collected from different poultry shops, which were initially analyzed for the presence of AF and OTA through thin layer chromatography (TLC) and then confirmed the contamination concentration through the enzyme-linked immunosorbent assay method. The results of the current study confirmed the incidence of contamination with AF and OTA by TLC and ELISA methods. The contamination level of AF ranged from 26.09 to 50.56 (mean = 41.22 ± 9.45) μg/kg, whereas the contamination level of OTA ranged from 50.13 to 6.21 (mean 42.60 ± 6.21) μg/kg. The contamination level of AF was found to be above the permissible level set by the Food and Drug Administration (20 μg/kg), whereas the contamination level of OTA was below the permissible limits. Moreover, the VFC values were also below the recommended level. The results showed that the association between AF, OTA, and moisture content was significant (p < 0.05). Mycotoxin contamination was significantly (p < 0.05) highest in the winter season. These findings suggested that continuous monitoring regimes might prevent mycotoxin contamination in poultry feed ingredients.

Cluster approach to the study of population health risks posed by contamination of food products with heavy metals

Food products are a source of energy and essential substances but also of anthropogenic contaminants such as heavy metals. The aim of the study was to assess population health risks posed by contamination of food products with heavy metals, taking into account peculiarities of food preferences. An epidemiological study of actual nutrition of adult population of Samara region was conducted, the sample size was 1,856 people. At the first stage, using factor analysis, respondents' adherence to a certain model of food preferences was established; at the second stage, 5 homogeneous groups (clusters) of people with similar types of nutrition were formed using cluster analysis. The first cluster included individuals with maximum commitment to a high level of consumption of all studied foods; the second cluster was characterized by commitment to consumption of high-calorie foods such as baked goods, confectionery, sausages, potatoes, eggs, and cheese. Individuals from the cluster 3 showed a distinct preference for consumption of vegetables, fruit and dairy products. Individuals from the cluster 4 had no special preferences for any of the studied foods. The fifth cluster included people who had maximum preference for meat and meat products, smoked meats, pickles and salted fish. The content of cadmium, mercury, lead, and arsenic in food products was assessed via atomic absorption and photometric methods. The study relied on using social and hygienic monitoring data from the Samara Regional Rospotrebnadzor (Federal Service for Surveillance on Consumer Rights and Human Wellbeing) collection. Risk assessment of carcinogenic and non-carcinogenic effects was carried out in each of the five formed clusters taking into account modern methodological approaches. It was found that in all food clusters, the hazard coefficients for intake of contaminants in median concentrations and in the 90th percentile did not exceed permissible levels. In all clusters, the endocrine system was most at risk (HI = 1.68 ÷ 1.25). For all clusters, carcinogenic risk (for median concentrations) was created by arsenic both at the individual and the population level. The risk was the highest for people whose diets were characterized by high levels of consumption of high-calorie products. Cluster approach makes it possible to identify the most vulnerable groups of population in terms of risk burden for making managerial decisions and carrying out preventive measures.

Heavy Metals Contaminants in Honey and Dry-Cured Meat Sold in Northern Nigeria Markets

Honey and dry-cured meat are common products for consumption and export in Nigeria but with a paucity of reports on their chemical contamination status. The occurrence of heavy metal residue in honey and dry-cured meat (Kilishi) for export in Kano and the Federal Capital Territory (FCT), Abuja, Nigeria and their safety status were investigated. The toxic metals profile in ninety samples of each animal product was established by Atomic Absorption Spectrometry (AAS, M5 Thermo Fisher Scientific, USA). The mean prevalence of Copper (Cu) in the honey samples from Kano Central was statistically higher than from other locations. Cadmium (Cd) contaminants occurred in the products at a range of 0.001-0.041 mg kg-1. Lead (Pb) and Cobalt (Co) were below detectable levels in all the samples. Due to the relatively high profile of Cu in both products, Cr in honey and Cd in the dry-cured meat, which was slightly higher than the permissible level in humans by the World Health Organization, there is a health risk concern. The Nigerian regulatory entities should always routinely monitor and enforce the set legislative laws to ensure a safe animal product for local consumption or export in Nigeria.