The term polychlorinated biphenyls, or PCBs refers to a class of synthetic organic chemicals that are, to a large degree, chemically inert. PCBs are not found in a nature as a natural compounds and its appearance in n...The term polychlorinated biphenyls, or PCBs refers to a class of synthetic organic chemicals that are, to a large degree, chemically inert. PCBs are not found in a nature as a natural compounds and its appearance in natural environment is connected with unintentional and irresponsible human activity. PCBs have been produced on an industrial scale for more than 50 years and have been exported as chemicals in products to almost every country in the world. PCBs were commonly used as dielectric fluids in transformers and capacitors, in heat transfer and hydraulic systems. Other uses of PCBs included the formulation of lubricating and cutting oils, as plasticizers in paints. Nowadays PCBs are ranked among the compounds called POP （Persistent Organic Pollutants）. This group of hazard removable pollutants includes pesticides, dioxins and furans also. Fishes fished from August 2006 to December 2007 from lakes in north-east Poland： Lafiskie, Kisajno and Niegocin. The investigations were carried out on four fish species： roach, common bream, perch and pike. According to the preliminary mass and length measurements anticipatory treatment were realized. Subsequently fishes were analysed in accordance with National Institute of Hygiene method. According to the investigations results PCBs were found in fish muscular tissues, fished from north-east lakes. PCB level didn＇t exceed the highest acceptable daily dose （4pg-TEQ body mass/day）.展开更多
This study was motivated by the world interest in the development of advanced processes of waste decomposition, due to the need of safer decomposition processes, particularly for the POPs （Persistent Organic Polluta...This study was motivated by the world interest in the development of advanced processes of waste decomposition, due to the need of safer decomposition processes, particularly for the POPs （Persistent Organic Pollutants） and the organochlorines. A tendency observed at several countries is the adoption of progressively more demanding legislation for the atmospheric emissions from the waste decomposition processes. The suitable final disposal of hazardous organic wastes such as PCBs （Polychlorinated Biphenyls）, pesticides, herbicides and hospital residues constitutes a serious problem. In some point of their lifecycles, these wastes should be destroyed, in reason of the risk that they represent for the human being, animals and plants. The process involves a chemical reactor containing molten salts, such as sodium carbonate or some alkaline carbonates mixtures to decompose the organic waste. The decomposition is performed by submerged oxidation. Waste is injected below the surface of a turbulent salt bath along with the oxidizing agent. Decomposition of halogenated compounds, among which some pesticides, is particularly effective in molten salts. The process presents properties such as intrinsically safe control of organochlorine emissions. This work describes the process developed at IPEN/CNEN-SP （Nuclear and Energetic Research Institute/Brazilian Nuclear Energy Commission） for complete thermal decomposition of hazardous wastes through oxidation submerged in molten salts.展开更多
文摘The term polychlorinated biphenyls, or PCBs refers to a class of synthetic organic chemicals that are, to a large degree, chemically inert. PCBs are not found in a nature as a natural compounds and its appearance in natural environment is connected with unintentional and irresponsible human activity. PCBs have been produced on an industrial scale for more than 50 years and have been exported as chemicals in products to almost every country in the world. PCBs were commonly used as dielectric fluids in transformers and capacitors, in heat transfer and hydraulic systems. Other uses of PCBs included the formulation of lubricating and cutting oils, as plasticizers in paints. Nowadays PCBs are ranked among the compounds called POP （Persistent Organic Pollutants）. This group of hazard removable pollutants includes pesticides, dioxins and furans also. Fishes fished from August 2006 to December 2007 from lakes in north-east Poland： Lafiskie, Kisajno and Niegocin. The investigations were carried out on four fish species： roach, common bream, perch and pike. According to the preliminary mass and length measurements anticipatory treatment were realized. Subsequently fishes were analysed in accordance with National Institute of Hygiene method. According to the investigations results PCBs were found in fish muscular tissues, fished from north-east lakes. PCB level didn＇t exceed the highest acceptable daily dose （4pg-TEQ body mass/day）.
文摘This study was motivated by the world interest in the development of advanced processes of waste decomposition, due to the need of safer decomposition processes, particularly for the POPs （Persistent Organic Pollutants） and the organochlorines. A tendency observed at several countries is the adoption of progressively more demanding legislation for the atmospheric emissions from the waste decomposition processes. The suitable final disposal of hazardous organic wastes such as PCBs （Polychlorinated Biphenyls）, pesticides, herbicides and hospital residues constitutes a serious problem. In some point of their lifecycles, these wastes should be destroyed, in reason of the risk that they represent for the human being, animals and plants. The process involves a chemical reactor containing molten salts, such as sodium carbonate or some alkaline carbonates mixtures to decompose the organic waste. The decomposition is performed by submerged oxidation. Waste is injected below the surface of a turbulent salt bath along with the oxidizing agent. Decomposition of halogenated compounds, among which some pesticides, is particularly effective in molten salts. The process presents properties such as intrinsically safe control of organochlorine emissions. This work describes the process developed at IPEN/CNEN-SP （Nuclear and Energetic Research Institute/Brazilian Nuclear Energy Commission） for complete thermal decomposition of hazardous wastes through oxidation submerged in molten salts.
