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Bulletin of the World Health... Apr 2022Multiple environmental health issues resulting from pollution and climate change threaten public health in India.
PROBLEM
Multiple environmental health issues resulting from pollution and climate change threaten public health in India.
APPROACH
The Government of India recognized the need for a permanent environmental health research institute; the Indian Council of Medical Research therefore established the National Institute for Research in Environmental Health in Bhopal in 2010. Scientists at the institute assessed the multiple long-term health effects of exposure to methyl isocyanate, and are now conducting research on a wide array of locally relevant environmental health issues.
LOCAL SETTING
The Union Carbide India Limited pesticide factory in Bhopal was the site of a methyl isocyanate gas leak in 1984, which affected half a million people. The Indian Council of Medical Research set up a coordinating unit in the immediate aftermath, which was upgraded to the Bhopal Gas Disaster Research Centre in 1986 and then the Centre for Rehabilitation Studies in 1995.
RELEVANT CHANGES
Scientists at the institute undertake environmental monitoring and health risk assessment studies among communities located near polluted areas, such as industrial areas. They are also assessing the training needs of practising physicians, with the aim of developing a curated curriculum to meet the deficiencies in environmental health education in the country.
LESSONS LEARNT
Environmental legislation was introduced in the wake of the disaster and a research institute in environmental health was established. Researchers at the institute have recognized the importance of engaging communities in environmental health research, as well as knowledge dissemination to relevant stakeholders.
Topics: Academies and Institutes; Environmental Exposure; Environmental Health; Environmental Pollution; Humans; India; Industry
PubMed: 35386553
DOI: 10.2471/BLT.21.286680 -
Environment International Apr 2022We report on the concentration ranges and combustion source-related emission profiles of organic and inorganic species released during 34 major industrial fires in the...
We report on the concentration ranges and combustion source-related emission profiles of organic and inorganic species released during 34 major industrial fires in the UK. These episodic events tend to be acute in nature and demand a rapid public health risk assessment to indicate the likely impact on exposed populations. The objective of this paper is to improve our understanding of the nature, composition and potential health impacts of emissions from major incident fires and so support the risk assessment process. Real world monitoring data was obtained from portable Fourier Transform Infrared (FTIR) monitoring (Gasmet DX-4030/40) carried out as part of the UK's Air Quality in Major Incidents service. The measured substances include carbon monoxide, sulphur dioxide, nitrogen dioxide, ammonia, hydrogen chloride, hydrogen bromide, hydrogen fluoride, hydrogen cyanide, formaldehyde, 1,3-butadiene, benzene, toluene, xylenes, ethyl benzene, acrolein, phosgene, arsine, phosphine and methyl isocyanate. We evaluate the reported concentrations against Acute Exposure Guideline Values (AEGLs) and Emergency Response Planning Guidelines (ERPGs), as well as against UK, EU and WHO short-term ambient guideline values. Most exceedances of AEGL or ERPG guideline values were at levels likely only to cause discomfort to exposed populations (hydrogen cyanide, hydrogen chloride, hydrogen fluoride and formaldehyde), though for several substances the exceedances could have potentially given rise to more serious health effects (acrolein, phosphine, phosgene and methyl isocyanate). In the latter cases, the observed high concentrations are likely to be due to cross-interference from other substances that absorb in the mid-range of the infrared spectrum, particularly when the ground level plume is very concentrated.
Topics: Acrolein; Air Pollutants; Benzene; Environmental Monitoring; Fires; Formaldehyde; Humans; Hydrochloric Acid; Hydrogen; Phosgene
PubMed: 35231840
DOI: 10.1016/j.envint.2022.107152 -
Environmental Analysis, Health and... Sep 2021Methyl isocyanate (MIC), a low molecular weight synthetic aliphatic compound, having an isocyanate group (-NCO), has industrial application. In this study, the effects...
Methyl isocyanate (MIC), a low molecular weight synthetic aliphatic compound, having an isocyanate group (-NCO), has industrial application. In this study, the effects of methyl isocyanate and its mechanism on outer membrane protein of Escherichia coli were observed using experimental and computational methods. In vitro exposure of N-succinimidyl N-methylcarbamate (NSNM) a synthetic analogue of MIC on E. coli to a final concentration of 2 mM was found to affect the growth curve pattern and changes in cell morphology. Molecular docking studies of MIC and NSNM with E. coli outer membrane protein (OmpW, OmpX, OmpF OmpA), and periplasmic domain (PAL) were performed. The in-silico results revealed that outer membrane protein OmpF showed the highest negative binding energy, i.e. ∆G -4.11 kcal/mole and ∆G -3.19 kcal/mole by NSNM and MIC as compared to other proteins. Our study concludes that methyl isocyanate retains lethal toxicity which leads to cell death due to the membrane protein damage of E. coli membrane.
PubMed: 34428861
DOI: 10.5620/eaht.2021020 -
Organic Process Research & Development Dec 2020The cyclic azodicarbonyl 4-methyl-1,2,4-triazoline-3,5-dione (MTAD) is a versatile and powerful reagent used mainly in cycloaddition chemistry. Though known for more...
The cyclic azodicarbonyl 4-methyl-1,2,4-triazoline-3,5-dione (MTAD) is a versatile and powerful reagent used mainly in cycloaddition chemistry. Though known for more than 50 years, its unsafe preparation, as well as purification by sublimation, hampered its widespread applicability on a larger scale. Herein we report a scalable and safe route to MTAD, which avoids the generation of methyl isocyanate. Moreover, we demonstrate that sublimation can be circumvented by the application of judicious oxidation conditions, followed by simple filtration. Overall, up to 25 g of MTAD was prepared in a single batch from commercial starting materials in three steps, with recrystallization serving as the only purification in the sequence. When employed in dearomative methodologies, the MTAD obtained by this protocol displayed synthetic efficiency equivalent to that of MTAD purified by sublimation.
PubMed: 33958851
DOI: 10.1021/acs.oprd.0c00470 -
Environmental Science and Pollution... Apr 2021Methylcarbamoyl mercapturic acid (MCAMA, N-acetyl-S-(N-methylcarbamoyl)-L-cysteine) is a urinary metabolite of N,N-dimethylformamide and methyl isocyanate, which are...
Characterization of US population levels of urinary methylcarbamoyl mercapturic acid, a metabolite of N,N-dimethylformamide and methyl isocyanate, in the National Health and Nutrition Examination Survey (NHANES) 2005-2006 and 2011-2016.
Methylcarbamoyl mercapturic acid (MCAMA, N-acetyl-S-(N-methylcarbamoyl)-L-cysteine) is a urinary metabolite of N,N-dimethylformamide and methyl isocyanate, which are volatile organic compounds that are harmful to humans. N,N-dimethylformamide exposure causes liver damage, and methyl isocyanate inhalation damages the lining of the respiratory tract, which can increase risk of chronic obstructive pulmonary disease and asthma. This study characterizes urinary MCAMA levels in the US population and explores associations of MCAMA concentrations with select demographic and environmental factors. We used liquid chromatography tandem mass spectrometry to measure MCAMA in urine collected from study participants ≥ 12 years old (N = 8272) as part of the National Health and Nutrition Examination Survey 2005-2006 and 2011-2016. We produced multiple regression models with MCAMA concentrations as the dependent variable and sex, age, fasting time, race/ethnicity, diet, and cigarette smoking as independent variables. Cigarette smokers and nonsmokers had median urinary MCAMA concentrations of 517 μg/g creatinine and 127 μg/g creatinine, respectively. Sample-weighted multiple regression analysis showed that MCAMA was positively associated with serum cotinine (p < 0.0001). Compared to non-exposed participants (serum cotinine ≤ 0.015 ng/mL), presumptive exposure to second-hand tobacco smoke (serum cotinine > 0.015-≤ 10 ng/mL and 0 cigarettes smoked per day) was associated with 20% higher MCAMA (p < 0.0001). Additionally, smoking 1-10 cigarettes per day was associated with 261% higher MCAMA (p < 0.0001), smoking 11-20 cigarettes per day was associated with 357% higher MCAMA (p < 0.0001), and smoking > 20 cigarettes per day was associated with 416% higher MCAMA (p < 0.0001). These findings underscore the strong association of tobacco smoke exposure with urinary MCAMA biomarker levels.
Topics: Acetylcysteine; Biomarkers; Child; Cotinine; Dimethylformamide; Humans; Isocyanates; Nutrition Surveys; Tobacco Smoke Pollution
PubMed: 33398732
DOI: 10.1007/s11356-020-12135-7 -
Ciencia & Saude Coletiva Oct 2020There is credible evidence that the 1984-Bhopal-methyl isocyanate (MIC)-gas-exposed long-term survivors and their offspring born post-exposure are susceptible to...
There is credible evidence that the 1984-Bhopal-methyl isocyanate (MIC)-gas-exposed long-term survivors and their offspring born post-exposure are susceptible to infectious/communicable and non-communicable diseases. Bhopal's COVID-19 fatality rate suggests that the MIC-gas tragedy survivors are at higher risk, owing to a weakened immune system and co-morbidities. This situation emboldened us to ponder over what we know, what we don't, and what we should know about their susceptibility to COVID-19. This article aims at answering these three questions that emerge in the minds of public health officials concerning prevention strategies against COVID-19 and health promotion in the Bhopal MIC-affected population (BMAP). Our views and opinions presented in this article will draw attention to prevent and reduce the consequences of COVID-19 in BMAP. From the perspective of COVID-19 prophylaxis, the high-risk individuals from BMAP with co-morbidities need to be identified through a door-to-door visit to the severely gas-affected regions and advised to maintain good respiratory hygiene, regular intake of immune-boosting diet, and follow healthy lifestyle practices.
Topics: Betacoronavirus; COVID-19; Communicable Disease Control; Coronavirus Infections; Disasters; Disease Susceptibility; Environmental Exposure; Humans; Immunocompromised Host; India; Isocyanates; Pandemics; Pneumonia, Viral; SARS-CoV-2; Self Care; Survivors; Vulnerable Populations
PubMed: 33027359
DOI: 10.1590/1413-812320202510.2.28682020 -
The Journal of Chemical Physics Aug 2020The vacuum-ultraviolet threshold photoelectron spectrum of methyl isocyanate CHNCO has been recorded from 10.4 eV to 12 eV using synchrotron radiation and a coincidence...
The vacuum-ultraviolet threshold photoelectron spectrum of methyl isocyanate CHNCO has been recorded from 10.4 eV to 12 eV using synchrotron radiation and a coincidence technique allowing for a mass-discrimination of the photoelectron signal. A significant improvement is achieved over previous investigations as this experimental setup leads to a much more resolved spectrum. Ten sharp peaks and a broad feature spanning 1.2 eV were recorded. This spectrum consists of X̃A←X̃ A and ÃA←X̃ A ionizing transitions. For the former, the adiabatic ionization energy was determined experimentally to be 10.596(6) eV; for the latter, its value was estimated to be 10.759(50) eV. Seven sharp peaks could be assigned to vibrational modes of the cation X̃A and neutral X̃ A ground electronic states involving only the NCO group atoms. Theoretical modeling of the threshold photoelectron spectrum has proven difficult as methyl isocyanate is a non-rigid molecule displaying large amplitude internal rotation of the methyl group and ∠CNC bending mode, leading to the quasi-symmetry. With the help of ab initio calculations, a theoretical model in which these two large amplitude motions are included in addition to the five small amplitude vibrational modes involving NCO group atoms is proposed. Comparison with the experimental spectrum shows that the broad feature and the strongest peak line positions are well accounted for; their intensities are also fairly well reproduced after adjusting a few parameters.
PubMed: 32828110
DOI: 10.1063/5.0017753 -
The Journal of Physical Chemistry. A Aug 2020The reaction of CHNC with OH radicals was studied in smog chamber experiments employing PTR-ToF-MS and long-path FTIR detection. The rate coefficient was determined to...
The reaction of CHNC with OH radicals was studied in smog chamber experiments employing PTR-ToF-MS and long-path FTIR detection. The rate coefficient was determined to be = (7.9 ± 0.6) × 10 cm molecule s at 298 ± 3 K and 1013 ± 10 hPa; methyl isocyanate was the sole observed product of the reaction. The experimental results are supported by CCSD(T*)-F12a/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ quantum chemistry calculations showing the reaction to proceed primarily via electrophilic addition to the isocyanide carbon atom. On the basis of the quantum chemical data, the kinetics of the OH reaction was simulated using a master equation model revealing the rate coefficient to be nearly independent of pressure at tropospheric conditions and having a negative temperature dependence with = 4.2 × 10 cm molecule s at 298 K. Additional quantum chemistry calculations on the CHNC reactions with O and NO show that these reactions are of little importance under atmospheric conditions. The atmospheric fate of methyl isocyanide is discussed.
PubMed: 32663395
DOI: 10.1021/acs.jpca.0c05127 -
Risk Analysis : An Official Publication... Sep 2020Model averaging for dichotomous dose-response estimation is preferred to estimate the benchmark dose (BMD) from a single model, but challenges remain regarding...
Model averaging for dichotomous dose-response estimation is preferred to estimate the benchmark dose (BMD) from a single model, but challenges remain regarding implementing these methods for general analyses before model averaging is feasible to use in many risk assessment applications, and there is little work on Bayesian methods that include informative prior information for both the models and the parameters of the constituent models. This article introduces a novel approach that addresses many of the challenges seen while providing a fully Bayesian framework. Furthermore, in contrast to methods that use Monte Carlo Markov Chain, we approximate the posterior density using maximum a posteriori estimation. The approximation allows for an accurate and reproducible estimate while maintaining the speed of maximum likelihood, which is crucial in many applications such as processing massive high throughput data sets. We assess this method by applying it to empirical laboratory dose-response data and measuring the coverage of confidence limits for the BMD. We compare the coverage of this method to that of other approaches using the same set of models. Through the simulation study, the method is shown to be markedly superior to the traditional approach of selecting a single preferred model (e.g., from the U.S. EPA BMD software) for the analysis of dichotomous data and is comparable or superior to the other approaches.
Topics: Bayes Theorem; Dose-Response Relationship, Drug; Isocyanates; Nitrosamines; Risk Assessment; Uncertainty
PubMed: 32602232
DOI: 10.1111/risa.13537 -
RSC Advances Apr 2020Isocyanurates are cyclic trimers of isocyanate molecules. They are generally known as highly thermostable compounds. However, it is interesting how the thermal...
Isocyanurates are cyclic trimers of isocyanate molecules. They are generally known as highly thermostable compounds. However, it is interesting how the thermal stabilities of the isocyanurate molecules will be altered depending on the substituents of their three nitrogen atoms. We performed computational investigations on the thermochemical behaviors of isocyanurate molecules with various alkyl and phenyl substituents. The cyclotrimerization processes of isocyanates are highly exothermic. Our best estimate of the enthalpy change for the cyclotrimerization of methyl isocyanate into trimethyl isocyanurate was -66.4 kcal mol. Additional negative cyclotrimerization enthalpy changes were observed for -alkyl-substituted isocyanates. This trend was enhanced with an extension of -alkyl chains. Conversely, low negative cyclotrimerization enthalpy changes were shown for secondary and tertiary alkyl-substituted isocyanates. The -alkyl-substituted isocyanurates were shown to be stabilized due to attractive dispersion interactions between the substituents. Meanwhile, the branched alkyl-substituted isocyanurates were destabilized due to the deformation of their isocyanurate rings. For various alkyl-substituted isocyanates, the sum of the deformation energy of the isocyanurate ring and the intramolecular inter-substituent nonbonding interaction energies was found to be linearly correlated with their cyclotrimerization energies. The cyclotrimerization energy for phenyl isocyanate was shown to have significantly deviated from the linear relationship observed for the alkyl-substituted isocyanurates. This is probably attributable to a remarkable change in the orbital resonance interactions during the cyclotrimerization of phenyl isocyanate to triphenyl isocyanurate.
PubMed: 35493671
DOI: 10.1039/d0ra02463e