Hydrogen Cyanide Concentration Research Articles

Validation of KASP Markers Associated with Hydrogen Cyanide in Fresh Cassava Roots in Uganda Cassava Germplasm

Low hydrogen cyanide (HCN) concentration is a high-priority trait for cassava varieties targeting their fresh and dry product profiles. To be acceptable, varieties bred and developed for these market segments must meet international safety standards for maximum acceptable residual levels of cyanide in cassava food and food products. The discovery of molecular markers that co-segregate with low HCN has not yet resulted in widespread usage in marker-assisted selection (MAS) in breeding programs. To deploy these HCN markers in regular MAS, assessing their reliability in various genetic backgrounds is crucial. The aim of this study was to assess the predictive accuracy of trait specific markers for HCN. The study used six HCN kompetitive allele-specific polymerase chain reaction (KASP) markers that had previously been developed in a Brazilian population and verified in segregating West African cassava populations. For most markers used in the study, the average call rate was more than 91.7%. Three markers—snpME00404, snpME00405 and snpME00406—showed a significant co-segregation of genotypes with the HCN phenotype. On average, genotypes that carried at least one copy of the favourable allele had lower HCN scores. The proportion of phenotypic variance accounted for by the three most important markers was 14% (snpME00406), 17% (snpME00405) and 27% (snpME00404). The validation of identified HCN SNP-markers marks a significant step in their deployment to support selection and advancement decisions in cassava breeding programs.

Comparative Study of the Proximate and Phytochemical Analysis of Polyalthia Longifolia (Fresh Bark and Leaves Leaves)

Proximate and phytochemicals are chemical components that are derived from plants through metabolic activities, Polyalthia longifolia is a very important plant. The phytochemical analysis results obtained for the bark for alkaloid, saponins, flavonoid, total phenol, hydrogen cyanide and terpenoid are as follows; 8.13, 9.31, 9.41. 42.7, 0.01 and 4.47 and for the leaves. 4.84, 3.21, 7.14, 2.96, 1.73 and 4.11 respectively. the proximate results carried out on its bark using standard procedures shows it contains (%) carbohydrate 51.7, moisture content 12.8, ash content 10.52, crude fibre 15.31 and crude protein 7.22 and the proximate results for leaves 4.48, 3.21, 7.14, 2.96 and 4.11 respectively for carbohydrate, moisture content, ash content, crude fibre and crude protein. This result shows that the plant is a good source of saponin, alkaloid, phenols, and terpenoids which contribute to the nutritive and medicinal potency of the plant. The concentration of hydrogen cyanide in the plant leaves and bark is not significant and therefore will have no lethal effect and can easily be detoxified but comparatively the leaves contain more cyanide than the bark which could be related to the moisture content, the total penol in the bark is also significantly higher than the leaves which show its effectiveness as an anti microbial agent. The high percentage of carbohydrate shows that the plant can be a good source of energy for both humans and animals. This plant has several benefits like anti-cancer, anti-oxidants and anti-haemohorrds and can be used to reduce fibroid, it is applicable industrially as food preservatives, cosmetics and sweetners,

Advancing CO2 to CO conversion: Detailed impact analysis of atmospheric molecules in an ultrashort pulse laser filament plasma reactor

AbstractCapturing carbon dioxide (CO2) and transforming it into valuable fuels offers a dual benefit: the potential to reduce atmospheric CO2 levels and decrease our dependency on fossil fuels. Plasma‐assisted CO2 to carbon monoxide (CO) conversion stands out within the various CO2 recycling methods, with research primarily emphasizing its energy efficiency and conversion efficacy. However, investigations of CO2 conversion under real air conditions are relatively scarce, and the effects of the other atmospheric molecules on the CO2 conversion process require further exploration. We have induced plasma chemical reactions by generating ultrashort pulse laser filaments inside a sealed‐off cavity with variable air pressures. Simultaneously, we applied mid‐infrared laser absorption spectroscopy to monitor the time evolution of the reaction products. The peak CO2‐to‐CO conversion ratio was achieved at an air pressure of 8000 Pa, which resulted in a CO concentration of 82 ppm. The experimental results suggested that nitrogen (N2) plays a promoting role in CO2‐to‐CO conversion, while the presence of oxygen (O2) seems to hinder the process. The hydroxyl radical (OH) arising from water molecules (H2O) limits the accumulation of CO at lower air pressures. However, at higher air pressures, the reduced OH radical concentration shows negligible impact on the CO2‐to‐CO conversion ratios. In addition, the study revealed that atmospheric plasmas produce a high concentration of hydrogen cyanide (HCN), which is directly proportional to the levels of ambient humidity. This research contributes to the development of strategies to mitigate the production of harmful gases like HCN in CO2 conversion, thereby promoting the ecofriendly conversion of atmospheric CO2.

Magnetic Susceptibility and Hydrogen Cyanide Levels as Proxy Indicator for Gold Mining Pollution in River Sediment

Sumbawa’s Kuris River is one of the rivers contaminated by the island’s traditional gold mine. In order to detect contaminant levels, we examine the magnetic susceptibility, HCN levels, and the heavy metal contents on the river’s surface sediment. Environmental pollution has been widely assessed using a combination of magnetic properties and geochemical analysis. The goals of this research are to discover how magnetic susceptibility (χ) can be used as a first-order proxy for pollution. The relation between susceptibility and HCN is of particular interest, as this is a major contaminant associated with gold mining. The surface sediment samples were collected at ten different locations along the rivers. The magnetic susceptibility was determined using the Bartington MS2B, and the hydrogen cyanide (HCN) concentration was determined using Argentometric titration. The element content was determined by an Atomic Absorption Spectrometer (AAS). The low-frequency magnetic susceptibility (χlf) ranges from 71 to 115×10-8 m3/kg, with an average of 97×10-8 m3/kg, and the χfd(%) analysis ranges from 2% to 4%. The presence of spherical iron oxides, which are indicative of combustion byproducts, was also confirmed by SEM. The samples have low magnetic susceptibility but high levels of Hg and HCN. AAS results showed high Fe, Zn, and Cu concentrations in river sediments, with more variable concentrations of Hg, Mn, As, Cr, and Au. Because Fe, Cu, As, Hg, and HCN have a significant Pearson’s correlation with χfd(%), this parameter can be a useful indicator for contamination caused by gold mining waste.

Atmospheric distribution of HCN from satellite observations and 3-D model simulations

Abstract. Hydrogen cyanide (HCN) is an important tracer of biomass burning, but there are significant uncertainties in its atmospheric budget, especially its photochemical and ocean sinks. Here we use a tracer version of the TOMCAT global 3-D chemical transport model to investigate the physical and chemical processes driving the abundance of HCN in the troposphere and stratosphere over the period 2004–2016. The modelled HCN distribution is compared with version 4.1 of the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) HCN satellite data, which provide profiles up to around 42 km, and with ground-based column measurements from the Network for the Detection of Atmospheric Composition Change (NDACC). The long-term ACE-FTS measurements reveal the strong enhancements in upper-tropospheric HCN due to large wildfire events in Indonesia in 2006 and 2015. Our 3-D model simulations confirm previous lower-altitude balloon comparisons that the currently recommended NASA Jet Propulsion Laboratory (JPL) reaction rate coefficient of HCN with OH greatly overestimates the HCN loss. The use of the rate coefficient proposed by Kleinböhl et al. (2006) in combination with the HCN oxidation by O(1D) gives good agreement between ACE-FTS observations and the model. Furthermore, the model photochemical loss terms show that the reduction in the HCN mixing ratio with height in the middle stratosphere is mainly driven by the O(1D) sink with only a small contribution from a reaction with OH. From comparisons of the model tracers with ground-based HCN observations we test the magnitude of the ocean sink in two different published schemes (Li et al., 2000, 2003). We find that in our 3-D model the two schemes produce HCN abundances which are very different to the NDACC observations but in different directions. A model HCN tracer using the Li et al. (2000) scheme overestimates the HCN concentration by almost a factor of 2, while a HCN tracer using the Li et al. (2003) scheme underestimates the observations by about one-third. To obtain good agreement between the model and observations, we need to scale the magnitudes of the global ocean sinks by factors of 0.25 and 2 for the schemes of Li et al. (2000) and Li et al. (2003), respectively. This work shows that the atmospheric photochemical sinks of HCN now appear well constrained but improvements are needed in parameterizing the major ocean uptake sink.

Online Detection of HCN in Humid Exhaled Air by Gas Flow-Assisted Negative Photoionization Mass Spectrometry.

Hydrogen cyanide (HCN) is a well-known toxic compound in many fields. The trace amount of endogenous HCN in human exhalation has been associated with the presence of Pseudomonas aeruginosa (PA) infection in cystic fibrosis (CF) patients. Online monitoring of HCN profile is promising to screen PA infection rapidly and accurately. In this study, a gas flow-assisted negative photoionization (NPI) mass spectrometry method was developed for monitoring the single-exhalation HCN profile. The sensitivity could be optimized by introducing helium to eliminate the humidity influence and reduce the low mass cutoff effect, with improvements of a factor 150 observed. By employing a purging gas procedure and minimizing the length of the sample line, the residual and response time were greatly reduced. The limit of detection (LOD) of 0.3 ppbv and time resolution of 0.5 s were achieved. HCN profiles of exhalations from different volunteers before or after gargling with water were detected to show the performance of the method. All profiles showed a sharp peak and a stable end-tidal plateau, representing the concentration of oral cavity and end-tidal gas, respectively. The HCN concentration based on the plateau of the profile showed better reproducibility and accuracy, which indicates this method has potential application in the detection of PA infection in CF patients.

Quantification of Elevated Hydrogen Cyanide (HCN) Concentration Typical in a Residential Fire Environment Using Mid-IR Tunable Diode Laser.

A versatile portable tunable diode laser based measurement system for measuring elevated concentrations of hydrogen cyanide (HCN) in a time-resolved manner is developed for application in the fire environment. The direct absorption tunable diode laser spectroscopy (DA-TDLAS) technique is employed using the R11 absorption line centered at 3345.3 cm-1 (2989.27 nm) in the fundamental C-H stretching band (ν1) of the HCN absorption spectrum. The measurement system is validated using calibration gas of known HCN concentration and the relative uncertainty in measurement of HCN concentration is 4.1% at 1500 ppm. HCN concentration is measured with a sampling frequency of 1 Hz, in gas sampled from 1.5 m, 0.9 m, and 0.3 m heights in the Fireground Exposure Simulator (FES) prop at the University of Illinois Fire Service Institute, Champaign, Illinois. The immediately dangerous to life and health (IDLH) concentration of 50 parts per million (ppm) is exceeded at all the three sampling heights. A maximum concentration of 295 ppm is measured at the 1.5 m height. The HCN measurement system, expanded to measure HCN simultaneously from two sampling locations, is then deployed in two full-scale experiments designed to simulate a realistic residential fire environment at the Delaware County Emergency Services Training Center, Sharon Hill, Pennsylvania.

Cyanide Poisoning.

Cyanide Poisoning.

Terahertz sensing with high sensitivity and substance identification capability using a novel High-quality resonance supported by a thin structured silicon film

We propose and numerically investigate a novel gas sensing structure with large sensitivity and the capability of substance selectivity, as well as high compactness based on the terahertz spectroscopic technique, by using a novel high-quality resonance, which is designed to match the absorption characteristic frequency of the target chemical. The resonance is achieved by employing the concept of bound state in the continuum (BIC), supported by a simple structure of silicon slab perforated by an interdigitated slot array with alternating slot width. An example of the detection of a toxic gas of HCN (hydrogen cyanide) was demonstrated and it is shown that a HCN concentration as low as 2 ppm in air under the atmospheric pressure of 1 atm can be detected with a slab thickness less than 100 μm. The selectivity of this assembled structure is also confirmed by introducing non-target Hydrogen bromide (HBr) gas, with no transmission drop at the original resonance. It refers to the conclusion that this structure shows great potential for practical applications for both gas identification and concentration monitoring.

Rapid measurements of hydrogen cyanide concentration in combustion gas via terahertz spectroscopy

The development of a real-time measurement system to determine the concentrations of combustion gases mixed with smoke particles in fire environments is an essential technical issue in the fire safety field. In this study, the absorption line for the J = 8–7 rotational transition at 708.9 GHz of hydrogen cyanide (HCN) produced by the combustion of silk is rapidly measured in a 1 m cell during repeat scans (seven times a minute) via terahertz spectroscopy. The obtained time profile of HCN concentrations agrees well with the time profile obtained via Fourier transform infrared (FT-IR) spectroscopy. The maximum concentrations derived via terahertz spectroscopy are consistent with those derived via FT-IR within an accuracy of 10%. The minimum sensitivity of HCN is 100 ppm as detected via terahertz spectroscopy. The repetition rate, the accuracy, and the sensitivity for the scans demonstrate the potential of terahertz spectroscopy to rapidly diagnose combustion gas flow concentrations in fire environments.

Sulfur, fresh cassava root and urea independently enhanced gas production, ruminal characteristics and in vitro degradability

BackgroundTotal fresh cassava root (FCR) production was 275 million tonnes in 2018 which equals 61.1 % of the total production, and Thailand produced 10.7 % FCR of the total production. FCR is one of the main energy source for ruminant. The limitation of FCR utilization is due to the presence of hydrogen cyanide (HCN). The study aimed to evaluate the effect of sulfur, urea and FCR at various levels on in vitro gas production, ruminal fermentation and in vitro degradability. The study hypothesized that: (1) sulfur, urea and FCR have no interaction effect and (2) effect of FCR and urea is related to sulfur addition.ResultsThe study aimed to elucidate the optimum level of elemental sulfur, fresh cassava root (FCR) and urea and their effect on in vitro gas production, ruminal fermentation, thiocyanate concentration, and in vitro degradability. A 3 × 2 × 4 in a completely randomized design were conducted. Factor A was level of sulfur at 0 %, 1 and 2 % of concentrate dry matter (DM), factor B was level of urea at 2 and 4 % of concentrate DM, and factor C was level of the FCR at 0, 200, 300 and 400 mg DM of the total substrate. The study found that elemental sulfur, urea and FCR had no interaction effect on the kinetics of in vitro gas, ruminal fermentation, HCN and in vitro degradability. Elemental sulfur supplementation (P < 0.05) significantly increased the in vitro gas produced from an insoluble fraction (b), in vitro DM degradability and either neutral detergent fiber (NDF) or acid detergent fiber (ADF) degradability and propionate (C3) concentration while decreased the ruminal HCN concentration. Urea levels showed a (P < 0.05) significant increase of the potential extent of in vitro gas production, ruminal ammonia nitrogen (NH3-N) and total volatile fatty acid (TVFA). Fresh cassava root supplementation (P < 0.05) significantly increased the in vitro gas produced from an immediate soluble fraction (a), in vitro gas produced from insoluble fraction, in vitro gas production rate constant, total VFA, C3 concentration and HCN while decreased ruminal pH, acetate and butyrate concentration. It could be concluded that 2 % elemental sulfur, 4 % urea and 300 mg FCR showed a greater effect on in vitro gas production, ruminal fermentation and HCN reduction.ConclusionsThe study found that elemental sulfur, urea, and FCR had no interaction effect on the kinetics of in vitro gas, total in vitro gas, ruminal fermentation, and HCN concentration. It could be concluded that 2 % elemental sulfur, 4 % urea, and 300 mg FCR showed a greater effect on in vitro gas production, ruminal fermentation, and HCN reduction.

Toxic Blood Hydrogen Cyanide Concentration as a Vital Sign of a Deceased Room Fire Victim-Case Report.

Carbon monoxide (CO) and hydrogen cyanide (HCN) are two common toxic products of combustion. HCN concentrations of fire victims are not routinely determined in most legal medicine services in Romania. We present the case of a room fire victim in which we evaluated the concentrations of HCN and carboxyhemoglobin (COHb), their contribution to the mechanism of death, and the possibility that HCN concentration can be interpreted as vital sign. COHb was determined by spectrophotometry. HCN was spectrophotometrically determined with ninhydrin in postmortem blood samples after its removal with 20% phosphoric acid and uptake into a solution of potassium carbonate. The presence of ethyl alcohol was determined by gas chromatography. The COHb concentration was 6.15%, while the blood HCN concentration was 1.043 µg × mL−1 and the total HCN was 1.904 µg × ml−1. A blood alcohol content of 4.36 g‰ and a urine alcohol content of 5.88 g‰ were also found. Although the fire produced a considerable amount of soot, and there were signs of inhalation of soot particles, the COHb level cannot be interpreted as a vital sign. Toxic concentrations of HCN and total HCN can be interpreted as a vital sign and indicates a contributive effect of HCN in the mechanism of death.

A portable NDIR sensor for rapid detection of hydrogen cyanide in environment

Cyanide pollution refers to the environmental pollution caused by cyanide and its compounds. As a derivative of cyanide, the leakage and excessive discharge of hydrogen cyanide will cause great harm to the surrounding animal and plant environment. Rapid detection of hydrogen cyanide can avoid some unnecessary environmental pollution. Based on the principle of non dispersive infrared(NDIR) detection, the infrared absorption of hydrogen cyanide at 3.0 μm and 14.3 μm was selected as the qualitative and quantitative basis. Two NDIR sensors were designed to detect 3.0 μm and 14.3 μm infrared absorption respectively after assembly. The standard curve between the concentration of hydrogen cyanide and the voltage response value was determined, and the performance of the two sensors was tested. Their detection ranges is 10ppm-3000ppm and 22ppm-3000ppm respectively. The maximum response time is less than 11s and RSD < 2%. After comparing the performance of the two sensors, the display values of the different sensors were processed. Finally, the two sensors were assembled into one sensor, the hydrogen cyanide concentration was displayed with one indication and different gases were mixed with hydrogen cyanide to pass into the gas chamber, which improved the anti-interference ability.

Research progress of quartz-enhanced photoacoustic spectroscopy based gas sensing

Laser spectroscopy based techniques have the advantages of high sensitivities, high selectivities, non-invasiveness and in situ, real-time observations. They are widely used in numerous fields, such as environmental monitoring, life science, medical diagnostics, manned space flight, and planetary exploration. Owing to the merits of low cost, compact volume and strong environment adaptability, quartz-enhanced photoacoustic spectroscopy (QEPAS) based sensing is an important laser spectroscopy-based method of detecting the trace gas, which was invented in 2002. Detection sensitivity is a key parameter for gas sensors because it determines their real applications. In this paper, focusing on the detection sensitivity, the common methods for QEPAS are summarized. High power laser including amplified diode laser by erbium doped fiber amplifier (EDFA), and quantum cascade laser are used to improve the excitation intensity of acoustic wave. The absorption line of gas molecules located at the fundamental bands of mid-infrared region is adopted to increase the laser absorption strength. Micro-resonator is employed to enhance the generated acoustic pressure by forming a standing wave cavity. Quartz tuning forks (QTFs) with low resonant frequency are used to increase the accumulation time of acoustic energy in itself. Multi-pass strategy is utilized to amplify the action length between laser beam and target gas in the prongs of QTF. The advantages and disadvantages of the above methods are discussed respectively. For the issues in real applications, the all-fiber strucure in near-infared region and mid-infrared region and miniaturization using three-dimensional(3D) printing technique for QEPAS sensor are summarized. A QEPAS technique based multi-gas sensor is used to quantify the concentration of carbon monoxide (CO), carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;), hydrogen cyanide (HCN), and hydrogen chloride (HCl) for post-fire cleanup aboard spacecraft, which is taken for example for the real application.Finally, the methods of further improving the sensitivity of QEPAS sensor are proposed.

Nutritional and Anti-Nutritional Factors in Vicia sativa L. Seeds and the Variability of Phenotypic and Morphological Characteristics of Some Vetch Accessions Cultivated in European Countries.

Simple SummaryThis study was designed to determine the contents of nutrients and some anti-nutritional factors in the seeds of common vetch (Vicia sativa L.) and the variation of phenotypic and morphological traits in field studies of 44 European accessions, originating from Russia, Ukraine, Poland, the Czech Republic, the Slovak Republic, Hungary, and Germany and grown in the same soil-climate conditions. The results of the research showed that common vetch seeds may be valuable protein-rich feed stuff, but their nutritional usefulness is limited by the presence of anti-nutritional factors.Agricultural research has traditionally focused on staple crops, while relatively little attention has been given to minor crops. Therefore, this study aimed to determine the nutrient contents and some anti-nutritional factors in the seeds of common vetch (Vicia sativa L.) and the variation of phenotypic and morphological traits in field studies of 44 European accessions, originating from Russia, Ukraine, Poland (east and east-central Europe), the Czech Republic, the Slovak Republic, Hungary (south-central Europe), and Germany (west-central Europe) and grown in the same soil-climate conditions. A three-year field study was conducted from 2010 to 2012. Accessions originating from west-central Europe flowered three days earlier than those from south-central Europe. They also had the lowest seed number per pod (5.9) but the highest thousand seed weight (58 g) (p < 0.05). Vetch lines coming from south-central Europe contained the highest level of crude protein in comparison with vetch seeds originating from west-central Europe (353 vs. 324 g kg−1, respectively) (p < 0.05), but the latter had the highest essential amino acid index value (75 vs. 71 in west-central Europe and south-central Europe, respectively) (p < 0.05). The highest protein level was noted in the seeds of Slovak origin (average 358 g kg−1), whereas the lowest protein level (324 g kg−1) was determined in the Russian and German lines. Vetch grain fat was rich in linoleic (53%) and linolenic (14%) acids. The best n-6/n-3 fatty acid ratio (4) and the highest α-linolenic acid level were exhibited by the Slovak and Polish accessions (p < 0.05). The seeds of vetch accessions from east, east-central, and south-central Europe contained higher levels of (p < 0.05) iron than those originating from west-central Europe. The concentration of tannins, trypsin inhibitors, and hydrogen cyanide reached on average 8, 3, and 81 mg kg−1, respectively. The highest hydrogen cyanide (HCN) levels was determined in the accessions of German and Russian origin (126 and 119 mg kg−1, respectively), and the lowest values were noted in the Slovak and Polish lines (50 and 67 mg HCN kg−1, respectively). Furthermore, the Polish accessions contained the lowest levels of tannins and trypsin inhibitors. Common vetch seeds may be valuable protein feed/food stuff, but their nutritional usefulness is limited by the presence of anti-nutritional factors, especially HCN, which is difficult to remove. Further selection in this direction may be postulated.

Large-scale genome-wide association study, using historical data, identifies conserved genetic architecture of cyanogenic glucoside content in cassava (Manihot esculenta Crantz) root.

Manihot esculenta (cassava) is a root crop originating from South America that is a major staple in the tropics, including in marginal environments. This study focused on South American and African germplasm and investigated the genetic architecture of hydrogen cyanide (HCN), a major component of root quality. HCN, representing total cyanogenic glucosides, is a plant defense component against herbivory but is also toxic for human consumption. We genotyped 3354 landraces and modern breeding lines originating from 26 Brazilian states and 1389 individuals were phenotypically characterized across multi-year trials for HCN. All plant material was subjected to high-density genotyping using genotyping by sequencing. We performed genome-wide association mapping to characterize the genetic architecture and gene mapping of HCN. Field experiments revealed strong broad- and narrow-sense trait heritability (0.82 and 0.41, respectively). Two major loci were identified, encoding for an ATPase and a MATE protein, and contributing up to 7 and 30% of the HCN concentration in roots, respectively. We developed diagnostic markers for breeding applications, validated trait architecture consistency in African germplasm and investigated further evidence for the domestication of sweet and bitter cassava. Fine genomic characterization revealed: (i) the major role played by vacuolar transporters in regulating HCN content; (ii) the co-domestication of sweet and bitter cassava major alleles are dependent upon geographical zone; and (iii) the major loci allele for high HCN in M.esculenta Crantz seems to originate from its ancestor, M.esculenta subsp. flabellifolia. Taken together, these findings expand our insights into cyanogenic glucosides in cassava roots and its glycosylated derivatives in plants.

Hydrogen cyanide and mycotoxins: Their incidence and dietary exposure from cassava products in Anyigba, Nigeria

While cassava products are important in addressing food security crises in Africa, they are not exempted from recurring food safety concerns. This research determined consumption, incidence, and concentrations of hydrogen cyanide (HCN), total aflatoxins (AFs), ochratoxin A (OTA) and fumonisins (FBs) in cassava product (casava flour, fufu and gari) among residents of Anyigba, Nigeria, and also estimated dietary exposure to the toxins from the foods. Consumption data from 82 households showed that 89%, 68% and 94% of the residents consume cassava flour, fufu, and gari, respectively. Average daily intake for individuals was 0.751, 0.111, and 0.120 kg of cassava flour, fufu, and gari respectively. The highest incidence and concentration of HCN were found in cassava flour, with %TDI (EDI) of 33.3% (0.03 mg/kg.bw/day). Weekly, residents are exposed to 0.0371, 0.0077 and 0.0224 μg/kg.bw of OTA, and daily to 0.0315, 0.0043, 0.0060 μg/kg.bw of AFs and 0.0000, 0.0025, 0.0004 μg/kg.bw of FBs from consumption of cassava flour, fufu, and gari, respectively. The mycotoxins also co-occurred in the food products.

Quantitative evaluation of hydrogen cyanide content, chemical and functional properties of gari from Akwanga, Nasarawa State, Nigeria

Ingestion of cyanohydrins has been linked to acute and chronic toxicities even death on several occasions in Nigeria. The need for periodic evaluation of cassava based food products to ensure compliance to standard specifications is therefore imperative. This study was conducted to investigate the concentration of hydrogen cyanide and other quality parameters of gari samples collected from Akwanga main market in the month of July, 2019. A total of 21 samples of gari (16 white and 5 yellow varieties) were collected using systematic random sampling techniques. Hydrogen cyanide, proximate compositions, physicochemical and functional properties were carried out following standard procedures. Results showed that white and yellow gari contained hydrogen cyanide in the range of 3.68–19.37 mg/kg and 13.32–16.17 mg/kg respectively. High moisture (11.38–16.74%) and crude fibre (1.51–3.44%) contents were recovered in some white gari and all the yellow gari samples. The results obtained for pH (4.44–5.95) and titratable acidity (0.11–0.67%) indicated low acid concentrations in both gari varieties. The bulk density, water absorption capacity, swelling index and least gelation capacity varied significantly in white and yellow gari samples as from 0.12–0.87 g/mL, 4.06–5.40 mL/g, 0.47–4.40 and 3.00–6.70% respectively. The concentrations of hydrogen cyanide in all the samples were higher than maximum value (2.0 mg/kg) considered as National Standard Specifications for gari coupled with high moisture contents above the safe level which might predispose them to mould growth that could render them unsafe for human consumption.

Defining the specific formation coefficient and the critical partial density of hydrogen cyanide and carbon monoxide at the fire indoors

Introduction . Modern mathematical models of the distribution of toxic gases use the values of specific coefficients of formation of only three gases. It is not considered the whole spectrum of toxic gases produced during the combustion of synthetic materials. Therefore, the experimental study of the process of hydrogen cyanide formation is an important task. Aims and purposes. The purpose of this article is to develop a methodology for obtaining initial data on the release of hydrogen cyanide. These data are necessary to calculate the time of blocking evacuation ways. To achieve it, the value of the critical concentration of hydrogen cyanide was justified. The experimental unit was modernized and experimental studies of partial densities of hydrogen cyanide and carbon monoxide, as well as specific coefficients of their release, were carried out during combustion of modern cable products. Methods . An experimental method is used to study the process of formation of hydrogen cyanide and carbon mono­xide during the combustion of samples of cable products in a modernized small-size experimental unit. The results were analyzed. Results . The critical value of the partial density of hydrogen cyanide, presented in normative documents, on the basis of analysis of data given in the literature sources, is substantiated. Experimental dependences between the time of testing and partial densities of hydrogen cyanide and carbon monoxide, as well as their specific coefficients of release, were obtained. This study reveals that the experimental value of the partial density of hydrogen cyanide reaches a critical value. That fact justifies the need to calculate the time of blocking the escape routes with con­sidering influence of hydrogen cyanide. Conclusion . The modernization of the experimental unit makes it possible to obtain experimental dependencies on the time of partial densities of hydrogen cyanide and carbon monoxide, as well as specific coefficients of their separation. This makes it possible to update (by HCN and CO) the existing database of typical fire load and to calculate the time of blocking the escape routes in case of combined effects of the above mentioned gases. When calculating fire risks in case of the burning of modern cable products, it is necessary to determine the time of blocking evacuation routes by hydrogen cyanide.

Human continuous hydrogen cyanide inhalation predictor with a physiologically based pharmacokinetic (PBPK) model.

Hydrogen cyanide (HCN) is volatile and highly toxic with acute and chronic effects on humans. Gaseous HCN enters the atmosphere from natural processes or industrial activities, which lead to human exposure. Effective intervention in cases of HCN inhalation requires an efficient diagnostic tool. The existing physiologically based pharmacokinetic (PBPK) model for HCN cannot clearly simulate continuous HCN inhalation or predict HCN levels in inhaled air. The current study presents a PBPK model for continuous inhalation of HCN, called Human Continuous Cyanide Inhalation Predictor (HCCIP). Since existing data on pharmacokinetics of HCN inhalation are limited, HCCIP utilizes extensive data from the current authors' PBPK model on cyanide ingestion. The structure of HCCIP comprises the lungs, kidneys, liver, and slowly perfused tissue. In both the human body and in exhaled air, HCCIP features the ability to predict concentration-time courses of cyanide. Moreover, HCCIP can predict HCN concentration in inhaled air from known blood cyanide levels. After completion, the results of HCCIP were validated against preexisting published datasets. The simulation results agreed with these datasets, validating the model. The HCCIP model is an effective tool for assessing risk from continuous HCN inhalation, and HCCIP extends the capabilities of air dispersion modeling, such as AERMOD or CALPUFF, to assess HCN risk from specific release sources.