Severe Visual Loss Caused by Inhalational Methanol Poisoning in Fireworks Production: A Report on 3 Cases

BACKGROUND Explosion injury is a common occupational injury with fireworks production. There are few reports about the relationship of severe visual loss and acute methanol poisoning in fireworks laborers. CASE SUMMARY Here we report 3 patients of visual loss caused by inhalation exposure to high concentration of methanol, who were engaged in the granulation process of fireworks manufacturing industry. They presented with severe metabolic acidosis and visual impairments, accompanied with headache, chest tightness, shortness of breath, dizziness and vomiting. One patient developed bilateral blindness and two patients improved after timely hemodialysis treatment.CONCLUSION This case report emphasizes the risk of methanol poisoning in the fireworks industry or other factories using commercial alcohol. Early hemodialysis intervention and metabolic acidosis correction are crucial for rescuing visual impairment caused by methanol exposure. The awareness and supervision of commercial alcohol are indispensable for similar industrial manufactures.

Estimates of Non-Alcoholic Food-Derived Ethanol and Methanol Exposure in Human

Food-derived alcohol is almost not in question due to its low concentration. Nevertheless, could it pose a problem for some risk groups and forensic cases? To answer this, we aimed to simultaneously evaluate ethanol and methanol ingredients of a variety of non-alcoholic foods in two different countries and estimate their possible health and forensic consequences. Alcohols in foods were analysed by headspace gas chromatography (HS-GC). Human average acute daily food consumptions and food-derived blood alcohol concentrations (BAC) were determined by using the data of the EFSA Nutrition Survey. Methanol and ethanol ingredients of similar foods varied between the two cities. Most foods produce higher methanol concentrations than the Maximum Allowable Dose Level (23 mg). Especially fruit juices lead to the critical level of ethanol for children (6.0 mg/kg bw). Based on the results, adult daily intake of selected food groups does not bear ethanol that exceeds the legal limit of BAC or the limit not allowed by the religious and does not lead to acute alcohol toxicity. But these low levels of ethanol and methanol consumed via non-alcoholic foods for life can raise the vulnerability to chronic health problems (cancer, liver cirrhosis, Alzheimer’s disease, autism, ocular toxicity, alterations in fetal development), and may lead to positive ethanol metabolite results (e. g. Ethyl glucuronide) when a low cut-off level is used. Therefore, studies on the alcohol contents of various natural and processed non-alcoholic foods along with their effects on humans, and new regulations on labeling the food products and conscious food consumption are in particular importance. It would also be important to consider unintentional alcohol consumption via non-alcoholic foods in the evaluation of clinical and forensic cases.

Toxic Effects of Methanol among Illegally Dispatched Workers at Aluminum CNC cutting process in Small-scale 3rd tier Subcontractor Factories of Smartphone Manufacturers in the Republic of Korea

An outbreak of occupational methanol poisoning occurred in small-scale 3rd tier factories of large-scale smartphone manufacturer, in the Republic of Korea, in 2016. To investigate the working environment and the health effect of the methanol exposure among co-workers of the methanol poisoning cases, we performed a cross sectional study on 155 workers at the five aluminum CNC cutting factories. Air and urinary methanol concentration were measured by gas chromatography, and health examination included symptoms, ophthalmological examinations and neurobehavioral tests. Multiple logistic regression analyses controlled for age and sex were conducted for revealing association of employment duration with symptoms. Air concentrations of methanol in factory A and E were ranged from 228.5 to 2220.0 ppm. Mean urinary methanol concentrations of the workers in each factory were from 3.5 mg/L up to 91.2 mg/L. The odds ratios for symptom of deteriorating vision and CNS increased, according to the employment duration, after adjusting for age and sex. Four cases with injured optic nerve and two cases with decreased neurobehavioral function were founded among co-workers of the victims. This study showed that the methanol exposure under poor environmental control not only produce eye and CNS symptoms but also affect neurobehavioral function and optic nerve.

The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites exposed to diluted methanol

The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites was studied after an exposure of 24 h in diluted methanol system by clamping test specimens across steel templates. The glass transition temperature ( Tg) and storage modulus increased steadily with the increase of halloysite nanoclays before and after diluted methanol exposure. The addition of nano-fillers was found to reduce liquid uptake by 0.6% in case of 1 wt% reinforcement compared to monolithic polyester. The mechanical properties of polyester-based nanocomposites were found to decrease as a result of diluted methanol absorption. After diluted methanol exposure, the maximum microhardness, tensile, flexural and impact toughness values were observed at 1 wt% of halloysite nanoclay. The microhardness increased from 203 to 294 HV (45% increase). The Young’s modulus increased from 0.49 to 0.83 GPa (70% increase) and the tensile strength increased from 23 to 27 MPa (17.4% increase). The impact toughness increased from 0.19 to 0.54 kJ/m2 in diluted methanol system (184% increase). Surprisingly, the fracture toughness of all types of nanocomposites was found to increase after exposing to diluted methanol due to plasticization effect. Scanning electron microscope images of the fractured surfaces of tensile specimens revealed that the methanol increased the ductility of the matrix and reduced the mechanical properties of the nanocomposites.

Silica Sol-Gel Entrapment of the Enzyme Chloroperoxidase

The enzyme chloroperoxidase (CPO) was immobilized in silica sol-gel beads prepared from tetramethoxysilane. The average pore diameter of the silica host structure (~3 nm) was smaller than the globular CPO diameter (~6 nm) and the enzyme remained entrapped after sol-gel maturation. The catalytic performance of the entrapped enzyme was assessed via the pyrogallol peroxidation reaction. Sol-gel beads loaded with 4 μg CPO per mL sol solution reached 9–12% relative activity compared to free CPO in solution. Enzyme kinetic analysis revealed a decrease inkcatbut no changes inKMorKI. Product release or enzyme damage might thus limit catalytic performance. Yet circular dichroism and visible absorption spectra of transparent CPO sol-gel sheets did not indicate enzyme damage. Activity decline due to methanol exposure was shown to be reversible in solution. To improve catalytic performance the sol-gel protocol was modified. The incorporation of 5, 20, or 40% methyltrimethoxysilane resulted in more brittle sol-gel beads but the catalytic performance increased to 14% relative to free CPO in solution. The use of more acidic casting buffers (pH 4.5 or 5.5 instead of 6.5) resulted in a more porous silica host reaching up to 18% relative activity.