Toxic radioactive elements

The principal among radioactive materials are the following isotopes °Co, °Sr, °Y, ° Ru, Cs, Ce, Pm, 238,239,240py Ra, and so on. The groups of toxic radioactive elements are presented in Table 5.1. Approximately 95% of radioactive pollutants are concentrated in the upper soil layer. Individual radioactive nucUdes are present in the soil in different forms. Depending on the soil composition, 8%-30% of radioactive nuclides are present in exchange forms, 2%-10% of them are in water-soluble forms, and 60%-85% in tightly bounded forms (Table 5.2). 

Nuclear-physical methods ai e the basic ones in controlling environmental pollution which results from nucleai -power complexes and power plants work. Oil and gas production leads to the extraction of radio nuclides of natural origin in considerable amounts, which later spread from oil-slimes and water wastes in the neighborhoods of oil and gas producing entei prises. Similaidy, toxic and radioactive elements can pollute environment in case of mineral deposits extraction. 

The chemistry, and hence hazards, of hot, or radioactive, elements parallels that of their cold isotopes. However, the radiation poses additional toxicity hazards. A qualitative classification of selected isotopes in terms of their toxicity is given in Table 10.2. The biological effects of ionizing radiation stem mainly from damage to individual cells following ionization of the water content. Oxidizing species, e.g. hydrogen peroxide. 

The dust and powder of thulium are explosive and toxic if inhaled or ingested. As with all radioactive elements, thuhum can cause radiation poisoning. 

Years of working with radioactive elements in the lab left Marie and Pierre Curie very sick as well. In 1934, Marie Curie died of a blood disease caused by exposure to radiation. When scientists examined her lab notebooks many decades later, they uncovered her glowing and toxic fingerprints everywhere. 

One of the most common topics asked of those who work with the actinides relates to handling procedures. The radioactive nature of these elements does require the use of special facilities, processes, and precautions. However, working with radioactive elements in subcritical quantities is as safe, if not safer, than handling many of the toxic chemicals found in a typical synthetic laboratory. The primary advantage in handling radioactive material is the ease with which these elements can be detected. Unlike other toxic chemicals, for example, lead, thallium, arsenic, and so on, a simple survey (seconds) with a radiation detector will show if containment of the material has been lost, where it is, and approximately how much is present. With appropriate monitoring, virtually no uptake of radioactive material occurs, and if any personnel contamination does occur, it is quickly detected and treated. 

Groudev, S. N., Spasova, 1.1., and Georgiev, P. S. (2001). In situ bioremediation of soils contaminated with radioactive elements and toxic heavy metals. Int. J. Miner. Process. 62, 301-308. 

Iyer, R. H. (2003). Separation and recovery of radioactive and non-radioactive toxic trace elements from aqueous industrial effluents. Indian J. Exp. Biol., 41, 1002-11. 

It should be noted that radioactive contaminants are not to be compared with their stable chemical counterparts. For example, because of the unchangeable character of the nuclear disintegration phenomenon, the natural purification processes which restore chemical and biological balances in the environments of living" things, would have no effect on the radio-toxic properties of the radioactive elements. The time required for accumulations of strontium-90 to decay to background levels, would... 

The toxicity indices are not measures of hazards, in part because they take no account of the barriers that isolate these wastes from the biosphere or of the behavior of different radioactive elements with respect to these barriers. However, the long-term toxicities of the high-level reprocessing wastes are due to radium, which is the same element that controls the ore toxicity. The long-term radium toxicity of the reprocessing wastes is considerably less than the radium toxicity of the ore. It seems reasonable that high-level wastes can be geologically... 

The table summarizes our knowledge about the essentiality, toxicity and isotopes of elements. It can be seen that the toxicity of elements depends on their chemical form. The isotopes of elements are rare cosmogenic nuclides. Nuclear fuel reprocessing, as well as reactor accidents, may release them to the biosphere. The isotopes are used as a radioactive tracer in medical practice. 

H5. Exposure of Earth life or human assets on Earth to toxic, radioactive, or energetic elements of the mission hardware [Al]... 

Because calcium and bicarbonate are non-toxic and widely available, co-precipitation of radioactive or toxic trace elements with calcite is a reasonable strategy to clean up industrial or radioactive waste solutions (Curti, 1999). Because mixed flow reactors can process a continuous stream of solution they might be employed to remove radioactive Co or radioactive Sr from a solution by co-precipitation with calcite. The reactor would mix a bicarbonate-rich solution with a calcium-rich solution containing the trace element, which would be trapped in the precipitating calcite. Let p (= be the fraction of M or Tr that... 

The remainder of the ore, containing most of the radioactivity and nearly all the rock material, becomes tailings, which are emplaced in engineered facilities near the mine (often in the mined-out pit). Tailings contain long-lived radioactive materials in low concentrations and toxic materials such as heavy metals however, the total quantity of radioactive elements is less than in the original ore, and their collective radioactivity will be much shorter-lived. These materials need to be isolated from the environment. 

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