ANTHROPOGENIC DISASTERS ON BULGARIAN TERRITORY: CHEMICAL ACCIDENTS ON LAND AND AT SEA

Natural and anthropogenic disasters become more frequent worldwide. As technology advances, the risk of major industrial accidents increases. Often accidents in the chemical and oil industry, in agriculture, or during transportation, lead to mass poisoning and extensive environmental pollution. The particularities of the medical support in case of such chemical incidents are challenging the healthcare system. The article aims to analyze the chemical accidents and the measures taken to reduce their effect in Bulgaria and in the Black sea aquatory. Historical and documentary methods have been used to gather information on disasters and accidents in Bulgaria, where toxic chemicals have been released into the environment, causing material damage and human casualties. We have researched and analyzed various articles and publications in Bulgarian and foreign scientific journals on the subject. Major industrial and transport accidents in the last 50-60 years on land and water had been selected from the literature sources. Both the reasons that led to them and the measures which were taken to eliminate the consequences were discussed. The major industrial accidents with a release of industrial toxic substances into the environment are relatively common and result in contaminating large areas and many casualties. Chemical accidents at sea are indicative of the need for joint action by different organizations to quickly overcome and avoid environmental impact. The risk of industrial poisonous substances entering the environment is significant and measures to avoid such accidents have to be taken, as well as training of a wide range of health professionals and the general public on the proper behaviour in case of a chemical disaster.

Recognition and Status of Response Equipment Related to Chemical Accidents and Terrorism

This study analyzes the perception, status, and problems of domestic firefighters related to chemical accidents and chemical terror response equipment. “How to use on-site response facilities and equipment” was 10% when “0 times” and 28.4% when “1 to 4 times,” indicating that the importance of the ‘experience’ category is greatly increased when there is a lack of relative experience. As for whether measurement equipment is retained, 20.0% of negative responses in the ‘special structure’ were found to differ in function by “Duty.” The effects of equipment-related proficiency and preference appear to be differences in equipment primarily held by special and chemical rescue teams. Problems with on-site response will require advisory experts on post-processing and analyses and the training of professional firefighters. Accordingly, through intensive interest and analyses in the field of special disaster responses, securing expertise, and fostering professional personnel, these problems can be addressed.

Assessment of Soil Contamination by Gas Cloud Generated from Chemical Fire Using Metabolic Profiling and Associated Bacterial Communities

Chemical accidents have frequently occurred in South Korea as a result of the huge amount of chemicals being used in various industries. Even though fire accidents accounted for 71.9% of chemical accidents during 2008–2018 in South Korea, most ecological research and investigation has focused on leakage accidents since most fire or explosion gases are diffused out and disappear into the atmosphere. In this study, the possibility of soil contamination by toluene combustion is proposed. A fire simulation batch test was performed and identified the combustion by-products such as methylbenzene, ethylbenzene, ethynylbenzene, benzaldehyde, 1-phenyl-1-propyne, naphthalene, 2-methylindene using gas chromatography coupled with mass spectrometry (GC–MS). Naphthyl-2-methyl-succinic acid, a metabolic intermediate of naphthalene metabolism derived from the combustion product of toluene, was also discovered in field soil and the secondary metabolites such as streptomycin 6-phosphate, 3-Nitroacrylate, oxaloacetate using LC–MS. Moreover, Streptomyces scabiei, participating in naphthalene metabolism, was also discovered in filed soil (contaminated soil) using 16s rRNA sequencing. As a result, bacterial stress responses in field soil (contaminated soil) affected by gas cloud were identified by discovering metabolites relating to bacterial self-defense action such as fatty biosynthesis. This study draws a conclusion that soil can be polluted enough to affect bacteria by gas cloud and soil bacteria and can encounter stress for a long term even though toluene and its combustion products had already decomposed in soil.

Study on Evaluation Model of Emergency Rescue Capability of Chemical Accidents Based on PCA-BP

The emergency management of chemical accidents plays an important role in preventing the expansion of chemical accidents. In recent years, the evaluation and research of emergency management of chemical accidents has attracted the attention of many scholars. However, as an important part of emergency management, the professional rescue team of chemicals has few evaluation models for their capabilities. In this study, an emergency rescue capability assessment model based on the PCA-BP neural network is proposed. Firstly, the construction status of 11 emergency rescue teams for chemical accidents in Shanghai is analyzed, and an index system for evaluating the capabilities of emergency rescue teams for chemicals is established. Secondly, the principal component analysis (PCA) is used to perform dimension reduction and indicators’ weight acquisition on the original index system to achieve an effective evaluation of the capabilities of 11 rescue teams. Finally, the indicators after dimensionality reduction are used as the input neurons of the backpropagation (BP) neural network, the characteristic data of eight rescue teams are used as the training set, and the comprehensive scores of three rescue teams are used for verifying the generalization ability of the evaluation model. The result shows that the proposed evaluation model based on the PCA-BP neural network can effectively evaluate the rescue capability of the emergency rescue teams for chemical accidents and provide a new idea for emergency rescue capability assessment.