RESUMO
Microorganisms developing in the liner of the spent fuel pool (SFP) and the fuel transfer channel (FTC) of a Nuclear Power Plant (NPP) can form high radiation resistant biofilms and cause corrosion. Due to difficulties and limitations to obtain large samples from SFP and FTC, cotton swabs were used to collect the biofilm from the wall of these installations. Molecular characterization was performed using massively parallel sequencing to obtain a taxonomic and functional gene classification. Also, samples from the drainage system were evaluated because microorganisms may travel over the 12-meter column of the pool water of the Brazilian Nuclear Power Plant (Angra1), which has been functioning since 1985. Regardless of the treatment of the pool water, our data reveal the unexpected presence of Fungi (Basidiomycota and Ascomycota) as the main contaminators of the SFP and FTC. Ustilaginomycetes (Basidiomycota) was the major class contributor (70%) in the SFP and FTC reflecting the little diversity in these sites; nevertheless, Proteobacteria, Actinobacteria, Firmicutes (Bacilli) were present in small proportions. Mapping total reads against six fungal reference genomes indicate that there is, in fact, a high abundance of fungal sequences in samples collected from SFP and FTC. Analysis of the ribosomal internal transcribed spacer (ITS) 1 and 2 regions and the protein found in the mitochondria of eukaryotic cells, cytochrome b (cytb) grouped our sample fungi in the clade 7 as Ustilago and Pseudozyma. In contrast, in the drainage system, Alphaproteobacteria were present in high abundances (55%). The presence of Sphingopyxis, Mesorhizobium, Erythrobacter, Sphingomonas, Novosphingobium, Sphingobium, Chelativorans, Oceanicaulis, Acidovorax, and Cyanobacteria was observed. Based on genomic annotation data, the assessment of the biological function found a higher proportion of protein-coding sequences related to respiration and protein metabolism in SFP and FTC samples. The knowledge of this biological inventory present in the system may contribute to further studies of potential microorganisms that might be useful for bioremediation of nuclear waste.
Assuntos
Cianobactérias/genética , Fungos/efeitos da radiação , Proteobactérias/genética , Tolerância a Radiação/efeitos da radiação , Biofilmes , Brasil , Corrosão , Cianobactérias/efeitos da radiação , Fungos/genética , Centrais Nucleares , Proteobactérias/efeitos da radiação , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/efeitos da radiação , Resíduos Radioativos/efeitos adversos , Microbiologia da ÁguaAssuntos
Formulação de Políticas , Resíduos Radioativos , Segurança , Humanos , New Mexico , Plutônio/efeitos adversos , Liberação Nociva de Radioativos/prevenção & controle , Liberação Nociva de Radioativos/estatística & dados numéricos , Resíduos Radioativos/efeitos adversos , Medição de Risco , Segurança/estatística & dados numéricosRESUMO
Radioactive lightning rods (RLR) were manufactured and installed in Brazil for almost two decades, before they were prohibited in 1989. Structures protected by this type of lightning preventers included residential buildings, schools, commercial and industrial facilities, among others. It is estimated that about 3.4 TBq of 241Am were used by manufacturers, and a total of 75,000 pieces with a mean activity of about 46 MBq were in the market. While only a fraction of the total has been recovered, the almost twenty thousand pieces already collected at the Nuclear and Energy Research Institute (IPEN) had their sources successfully separated from the remaining recyclable metal scrap and are now encapsulated in lead containers for final disposal.
Assuntos
Amerício/efeitos adversos , Resíduos Radioativos , Gerenciamento de Resíduos , Amerício/análise , Brasil , Humanos , Raio , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Resíduos Radioativos/efeitos adversos , Resíduos Radioativos/análise , Gerenciamento de Resíduos/métodosRESUMO
Radioactive lightning rods were manufactured in Brazil until 1989, when the licenses for using radioactive sources in these products were lifted by the national nuclear authority. Since then, these rods have been replaced by the Franklin type and collected as radioactive waste. However, only 20% of the estimated total number of installed rods has been delivered to the Brazilian Nuclear Commission. This situation causes concern, since there is the possibility of the rods to be disposed as domestic waste. In Brazil, 64% of the municipal solid waste is disposed at garbage dumps without sufficient control. In addition, (241)Am, the radionuclide most commonly employed, is classified as a high-toxicity element, when incorporated. In the present study, (241)Am migration experiments were performed by means of a lysimeter system, in order to evaluate the risk of contamination caused by radioactive lightning rods disposed as common solid waste. (241)Am sources removed from lightning rods were placed inside lysimeters filled with organic waste that was collected at the restaurant of the Instituto de Pesquisas Energéticas e Nucleares. The generated leachate was periodically analyzed, and characteristics such as pH, redox potential, solid content and the concentration of the radioactive material were determined. The equivalent dose for members of the public was calculated considering ingestion of contaminated drinking water as the major path of exposure. Estimated doses were about 20-times below the effective dose limit of 1 mSv year(-1) for members of the public as recommended by the International Commission on Radiological Protection. This suggests the radiation risk caused by lightning rods disposed at uncontrolled garbage dumps to be low. It should be noted, however, that the number of investigated lightning rods was quite small. The results of this study might therefore not be entirely representative and should be interpreted with care. They provide, however, a very first basis for characterizing the transfer of (241)Am from lightning rods to the human food chain.
Assuntos
Amerício/análise , Contaminação Radioativa de Alimentos/análise , Resíduos de Alimentos , Amerício/efeitos adversos , Brasil/epidemiologia , Exposição Ambiental/efeitos adversos , Substâncias Perigosas/efeitos adversos , Substâncias Perigosas/análise , Humanos , Resíduos Industriais/efeitos adversos , Resíduos Industriais/análise , Monitoramento de Radiação , Resíduos Radioativos/efeitos adversos , Resíduos Radioativos/análise , Radioisótopos/efeitos adversos , Radioisótopos/análise , Medição de Risco , Poluentes Químicos da Água/análise , Contaminação Radioativa da Água/efeitos adversos , Contaminação Radioativa da Água/análiseRESUMO
Radiation hazards in dental practice have long been recognized, and the dangers from ionising radiation during dental radiography are discussed elsewhere. Continuing legislation will undoubtedly help reduce the risk of over-exposure and accidents. Nevertheless, it is of some concern that radiation safety is still ignored by some: for example, one recent survey in the UK showed that not all radiography sets conformed to modern safety standards. However, the profession also has reason to be concerned about more public radiation hazards that may affect them, and their families and others, and may, without denying the importance of dental radiation protection, have far greater effects on health. Well-known examples of domestic radon exposure occurred in the UK, particularly in the Lake District and the South West, and the nuclear reactor accidents--notably at Chernobyl in 1986.
Assuntos
Acidentes , Césio/efeitos adversos , Cloretos , Doenças da Boca/etiologia , Lesões por Radiação/etiologia , Resíduos Radioativos/efeitos adversos , Brasil , Candidíase Bucal/etiologia , Humanos , Púrpura/etiologia , Estomatite Aftosa/etiologiaRESUMO
8 patients with bone marrow failure after a caesium-137 radiation accident were treated with recombinant human granulocyte-macrophage colony stimulating factor (rHuGM-CSF). The 7 who were evaluable had prompt increases in granulocytes and bone marrow cellularity. 2 patients died of radiation toxicity and haemorrhage and 2 of bacterial sepsis acquired before the start of rHuGM-CSF treatment. 4 patients survive, including 2 who were treated early and never became infected. This therapeutic approach to radiation-induced granulocytopenia may therefore be useful after radiation and nuclear accidents.