Radium-226

Radiation Toxicology, Ionizing and Nonionizing

B.R. Scott , in Encyclopedia of Toxicology (Third Edition), 2014

Radium-Punch Painters

Radium, as radium-226 and radium-228, was used in luminous paints in the period 1920–1950. Large amounts of radium were ingested by painters of watch and instrument dials as they tipped their brushes by mouth to achieve a fine point. The radium, one time ingested, behaves chemically like calcium and, therefore, deposits in significant quantities in os mineral, where it is retained for a very long time. Beingness an α-emitting radionuclide, the radium irradiates bone surface-lining cells and has resulted in an excess incidence of osteogenic sarcomas. Of interest in these patients has been the observation of a very large 'applied dose threshold' (and related dose-rate threshold) from radium-226, below which bone cancers practise not announced to occur. This has besides been observed in some experimental brute studies.

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AIR–Ocean INTERACTION | Gas Exchange

P.D. Nightingale , in Encyclopedia of Atmospheric Sciences, 2003

Radon

Radioactivity of radium-226 ( 226Ra) to the gas radon-222 (222Rn) occurs within the water column and radon is therefore transferred from the surface mixed layer to the temper. A mass budget tin can exist made of the 'missing' radon by assuming steady land with deeper waters and a value for one thousand Rn can be derived. The mean value for k COii obtained using this technique is about 14   cm   h−one (corrected from m Rn by assuming northward0.five). The radon data show a large amount of besprinkle with wind speed and the technique has shortcomings in that the status of steady state is rarely fulfilled.

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The Atmosphere and Associated Processes

Grady Hanrahan , in Central Concepts in Ecology Chemistry, 2012

Deposition of Radionuclides

Recall our give-and-take in Chapter 4 on the alpha decay of Radium-226 to Radon-222 and its power to be distributed through soils. Much of the Radon-222 concentration emanates from the soils to the temper, with additional sources emanating from groundwater, and from a lesser extent, the oceans ( Appleby and Piliposian, 2010). As was shown in Figure 4.ten, Radon-222 decays via a number of curt-lived isotopes to Atomic number 82-210. This readily occurs in the atmosphere, although Lead-210 has a relatively brusque lifetime. Individual Lead-210 atoms become attached to airborne particulate thing and are removed both by wet and dry degradation. An illustrated instance of the global balance of Radon-222 and Pb-210 in the atmosphere is shown in Effigy 6.x. To extend our word above, the Radon-222 inventory is balanced past the emission charge per unit from soils (labeled as A L F) and the rate of decay of Pb-210. Considering Pb-210, its inventory is balanced past the rate of production by Radon-222 disuse and the rate of loss (A E P) past fallout dorsum to the Earth's surface. Ultimately, the distribution of Radon-222 entering the atmosphere from dedicated sources is influenced by advection, diffusion, and radioactive decay processes.

Figure 6.10. An illustrative example of the global balance of Radon-222 and Pb-210 in the temper.

 Modified from (Appleby and Piliposian, 2010) with permission from ILM Publications.

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Pollution, Indoor Air

D. Schwela , in Encyclopedia of Toxicology (Third Edition), 2014

Radon

Radon (222 Rn) is an odorless and colorless natural radioactive gas. It is produced during the radioactivity of radium-226, itself a decay product of uranium-238 found in many types of crustal materials, i.e., rocks and soils. 222Rn has a short half-life (3.8 days) and decays into a series of solid particulate products known as radon progenies or daughters, about of which have fifty-fifty shorter half-lives (30 min or less). Other isotopes of radon also occur naturally, but due to differences in one-half-life and dosimetry, their health significance is minimal compared to that from exposure to 222Rn.

The main source of indoor air radon is the soil and rock beneath a edifice, from which the gas penetrates indoors, primarily through cracks or openings in the foundation or basement, including bleed and utility access areas. Some well (footing) h2o in areas having high soil radium content may also exist a source of indoor radon, as may natural gas or building materials containing radium. Often radon levels indoors tend to be highest in the lowest levels of a edifice, from which the gas tin can then permeate the entire structure. Arithmetic hateful radon concentrations in European countries range from nigh xxx to 140 Bq m− 3. In Russia, radon levels range between nineteen and 230 Bq grand− 3; in the U.s. average levels are around 50 Bq m− 3; in Canada and Argentina levels around 35 Bq m− 3 take been observed. In South and Due south-East Asian countries 222Rn arithmetic mean levels range between 16 and sixty Bq yard− iii. Considering of the skewed distribution of radon levels the geometric mean concentrations range 20–50% lower.

Depending on the geological compositions and socioeconomic considerations, recommended indoor activity levels vary from state to state. Many countries have ready an activeness level of 200 Bq k− 3 at which mitigation measures should be taken to reduce radon levels at home. In the European Customs, the action level is 400 Bq m− 3. In Canada the action level is set at 800 Bq m− 3. The highest acceptable level of residential radon in the United States has been set by the US EPA at 150 Bq m− 3, but almost 5–x% of homes in the United States exceed this benchmark.

The take a chance from radon exposure is essentially due to inhalation of its progeny, which tin can attach to abundant sources of particles in indoor air that and then act as carriers of these radioactive particles into the respiratory tract. Radon accounts for up to 50% of the total internal dose from all natural background radiations sources and this, in turn, is due almost completely to 2 of its progeny, namely, polonium-218 and polonium-214, that decay via the release of alpha particles. Alpha particles lodged in the airways of the lung can impairment the cells lining the airways, thus inducing lung cancer.

Radon exposure in the home likely substantially increases lung cancer risk in either nonsmokers or smokers. Radon is classified by IARC equally a Group I man carcinogen. The average excess relative risk, based on xxx years boilerplate radon exposure of smokers, ex-smokers, and lifelong nonsmokers is virtually 16% per increment of 100 Bq yard− iii. As the relative risk of lung cancer at whatsoever given radon concentration is approximately 26-fold higher in electric current smokers than in lifelong nonsmokers, the absolute run a risk of lung cancer due to radon is appreciably higher for current and ex-smokers than for lifelong nonsmokers. The WHO estimated the excess lifetime risks (by the age of 75 years) to correspond to a unit risk of 0.6 × ten−five per Bq m− three for lifelong nonsmokers and 15 × 10−5 per Bq m− iii for smokers. In consequence, for the direction of the radon challenge, the WHO International Radon Projection has recommended a reference level of 100 Bq m− iii to minimize health hazards due to indoor radon exposure.

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Pollution, Air Indoor

Dieter Schwela , Dimitrios Kotzias , in Encyclopedia of Toxicology (Second Edition), 2005

Radon

Radon (Rn-222) is an odorless and colorless natural radioactive gas. It is produced during the radioactive decay of radium-226, itself a decay production of uranium-238 establish in many types of crustal materials, that is, rocks and soils. Rn-222 has a short one-half-life (3.8 days) and decays into a serial of solid particulate products, known equally radon progeny or radon daughters, all of which have even shorter one-half-lives (∼30  min or less). Other isotopes of radon too occur naturally, but due to differences in half-life and dosimetry their health significance is minimal compared to that from exposure to Rn-222.

The main source of indoor air radon is the soil and stone below a building, from which the gas penetrates indoors, primarily through cracks or openings in the foundation or basement, including bleed and utility admission areas. Some well (ground) water in areas having high soil radium content may also be a source of indoor radon, as may natural gas or building materials containing radium. Ofttimes radon levels indoors tend to be highest in the everyman levels of a building, from which the gas can then permeate the entire structure. Arithmetics mean radon concentrations in European countries range from ∼xxx to 140   Bq   m−three. In Russia, radon levels range between nineteen and 230   Bq   m−3; in the Usa boilerplate levels are effectually 50   Bq   thou−3. Considering of the skewed distribution of radon levels the geometric mean concentrations range 20–50% lower. Many countries have set an activity level of 200   Bq   chiliad−3 at which mitigation measures should be taken to reduce radon levels at home. In the European Community, the activity level is 400   Bq   m−3. The highest adequate level of residential radon has been fix by the United states EPA at 150   Bq   thousand−iii, but ∼v–10% of homes in the Us exceed this benchmark.

The run a risk from radon exposure is substantially due to inhalation of its progeny, which can adhere to abundant sources of particles in indoor air that then act as carriers of these radioactive particles into the respiratory tract. Radon accounts for up to 50% of the total internal dose from all natural background radiations sources and this, in turn, is due virtually completely to two of its progeny, namely, polonium-218 and polonium-214, which decay via the release of α-particles. Alpha particles, while lodged in the airways of the lung tin can damage the cells lining the airways, thus inducing lung cancer.

Radon exposure in the home probable essentially increases lung cancer risk in either nonsmokers or smokers. According to a nationwide Swedish epidemiological study of lung cancer due to radon exposure, the attributable proportion of lung cancer related to residential radon exposure ranges between ii% and 5% for lifetime exposure to 25   Bq   chiliad−three, five–9% for lifetime exposure to l   Bq   m−iii, and 9–17% for lifetime exposure to 100   Bq   one thousand−three. The WHO estimated that these owing proportions of lung cancer correspond to a unit risk of 3–6×10−5  per   Bq   m−3. The (Usa) National Academy of Sciences, in 1998, has estimated that betwixt 15   400 and 21   800 lung cancers per yr in the United States can be attributed to radon exposure. Furthermore, the private risk may increment if other cancer-associated factors, especially cigarette smoke, are also present.

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Radium

Southward.C. Gad , in Encyclopedia of Toxicology (Third Edition), 2014

Exposure and Exposure Monitoring

Radium is a silvery-white radioactive metal found in most soils and rocks, although unremarkably present in minor quantities. Virtually anybody is exposed to depression levels of radium in inhaled air and ingested water and food. The concentrations of radium-226 and radium-228 in drinking water are generally low, simply there are specific geographic regions where high concentrations of radium occur due to geologic sources. Radium is a product of uranium and thorium breakdown and is present in all uranium ores. It undergoes spontaneous disintegration to form radon. People living most industries that burn coal or other fuels or in areas where uranium is abundant tin can expect to have higher exposures to both radium and radon. Miners and people living or working around radioactive waste disposal sites are as well exposed to higher levels of radium than the general public.

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The Role of H2o in Anarchistic in Situ Free energy Resource Extraction Technologies

Tanya J. Gallegos , ... Marker Engle , in Food, Energy, and Water, 2015

Reuse of Wastewaters from Uranium ISR Operations

The untreated wastewaters from ISR processes are classified as by-product. Equally such, reuse of untreated wastewaters in agriculture is problematic due to radionuclides and other potentially toxic constituents. Table 1 lists typical water qualities of various waste streams and treatment effluents expected at future ISR sites. 65,77 Table 1 shows an expected typical range of Ra-226 concentrations of waste streams from <5 to 300   pCi per liter (pCi/L Ra-226) 65 with some time to come ISR sites projecting as high as 3000   pCi/Fifty Ra-226 in wastewaters. 72 Wastewater extracted during post-ISR groundwater restoration slated for disposal represents the largest potential water volumes for reuse in agriculture or other applications, but some challenges remain. For example, reuse would demand advanced treatment to meet reuse standards and suitable and (or) economic methods for treatment of reject brines such equally (1) land available for evaporation of waste brines, (ii) wells available for disposal of waste brines, or (3) economic methods to concentrate waste brines into smaller volumes. Furthermore, fifty-fifty with avant-garde treatment, a major restriction to reuse could stem from high Ra-226 concentrations similar to the projected concentrations of thirty   pCi/L Ra-226 that persist in the "make clean" RO permeate water in Tabular array 1. This concentration is on the order of six times higher than the acceptable MCL established by EPA of v   pCi/L Ra-226. 81 So, not merely is Ra-226 a problem for reuse of untreated waters in agriculture, but information technology could also exist a problem in RO-treated waters. Since Ra-226 decays to radon-222 (Rn-222) gas, this further suggests that Rn-222 may also pose a pregnant barrier to both recycling and reuse. Some other issues related to reuse of ISR wastewater are similar for beneficial reuse of produced waters discussed in particular in the next section.

Table 1. Projected Wastewater Quality for Disposal via Class I Deep Disposal Wells and Land Application and Reinjection

Analyte Grade I Deep Wells (Untreated) a Land Application (Post-obit IX/Radium Removal) a Reinjection
Water Softener Brine Resin Rinse Elution Drain Yellowcake Wash Water Restoration Wastes RO Permeate b
pH 6.5–7.v half-dozen.5
Total dissolved solids, TDS 1000–5000 200
Conductivity, μS/cm 1500–6000 300
Alkalinity as CaCOthree 100
Bicarbonate 600–900 400–700 fifty–300 150
Calcium 3000–5000 200–1000 0
Carbonate 500–800 300–600 &lt;1
Chloride fifteen,000–20,000 10,000–15,000 12,000–15,000 4000–6000 300–1300 15
Magnesium 1000–2000 fifty–300
Potassium 10
Sodium 10,000–xv,000 6000–11,000 6000–8000 3000–4000 380–720 100–500 50
Sulfate 100–200 500–2000 15
Sodium adsorption ratio 2–6 (Unitless)
Arsenic 0.one–0.iii 0.01 0
Barium 0.4
Cadmium 0.3
Chromium 0.4
Copper 0.3
Iron 0.two
Molybdenum &lt;0.ane
Nickel 0.three
Selenium 0.05–0.15 &lt;0.2 0
Uranium &lt;1 1–3 5–10 3–5 &lt;one 0
Vanadium &lt;x
Lead-210, pCi/L &lt;10
Radium-226, pCi/50 &lt;v 100–200 100–300 20–50 fifty–100 &lt;sixty 30
Thorium-230, pCi/L &lt;5 50–100 10–30 x–20 50–150 &lt;100
U-natural, pCi/L &lt;300
Gross alpha, pCi/Fifty 2000–3000
Gross beta, pCi/L 2500–3500

Values in milligrams per liter, unless otherwise noted. RO, reverse osmosis.

a
Ref.65.
b
Ref.77.

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Thermoplastic Containers for Disposal of Radioactive waste

Ranvijay Kumar , Rupinder Singh , in Reference Module in Materials Science and Materials Engineering, 2020

High-Level Waste material

The treatment and transportation high level radioactive required the shielding in the course of robust containers to preclude the exposure. It is necessary to take proper cooling of loftier-level nuclear waste before disposal. The waste material is termed equally the hazards if information technology contains nuclides of thorium-230, radium-226, radon-222, and polonium-210. The high-level wastes are more often than not geological formulations such equally stable, deep body of water sub-seabed durable containers. Due to the high radioactivity level, the high-level wastes tending with much more careful handling and shielding. Information technology should be noted that high-level radioactive waste can be sustained for the k of the years and then that it must deposit non-public streams ( U.s. Nuclear Regulatory Committee; Nuclear Energy Bureau, 1989).

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NUCLEAR Chemistry

Therald Moeller , ... Clyde Metz , in Chemistry: With Inorganic Qualitative Analysis, 1980

8.6 Half-life

A convenient fashion of characterizing a radioactive isotope is by its half-life—the time it takes for one-half of the nuclei in a sample of a radioactive isotope to disuse. For example, consider an isotope with a half-life (t 1/two) of 10 years. Suppose 100 one thousand of this isotope is put away today. X years from today l yard of the original isotope will remain, along with the more than stable decay products. 10 years subsequently that, 25 g of the original isotope will exist left, and so on.

A radioactive decay curve for radium-226, which has a one-half-life of approximately 1600 yr, is given in Figure eight.half dozen. Half-lives of radioactive isotopes range from a few microseconds to as long every bit x15 yr (Table eight.ane).

FIGURE eight.6. Radioactive decay curve for 88 226Ra . This isotope has a one-half-life of approximately 1600 yr.

Table eight.one. Some radioisotope half-lives

Sodium-24, iron-52, and cobalt-60 are produced in accelerators for use in medical handling or diagnosis. Strontium-90, iodine-131, and cesium-137 have been introduced to the atmosphere equally fallout from nuclear weapons testing.

Isotopes Half-life
Radioisotopes produced on earth by catholic rays
i 3H (tritium) 1226 yr
6 14C 5770 twelvemonth
Natural radioisotopes
nineteen 10K one.three × 109 yr
60 144Nd 5 × tenxv year
90 232Th ane.39 × 1010 yr
92 235U 7.13 × 108 yr
92 238U 4.49 × tenix yr
Bogus radioisotopes
11 24Na 15 60 minutes
26 52Fe 8.3 hr
27 60Co 5.26 twelvemonth
38 90Sr 28 twelvemonth
35 87Br 5.5 sec
53 131I 8.1 days
55 137Cs 30 yr
94 239Pu 24,000 yr

Ingenious use has been made of carbon-14 to determine the age of institute and animal relics. The concentration of carbon-14 on Earth is kept relatively constant past a residuum between its rate of formation by cosmic ray neutron (due north) bombardment of nitrogen

vii 14 North + n → 6 14 C + ane 1 H

and its rate of decay by emitting electrons (due east −)

half-dozen 14 C → vii 14 Due north + east −

Every bit long every bit a plant or animal lives, it contains the same proportion of 6 14C equally its surroundings. But equally presently as a plant stops utilizing CO2 or an fauna stops eating carbon-containing plants, its supply of 6 14C is no longer replenished, and the ratio of radioactive 6 xivC to nonradioactive six 12C begins to subtract. From the one-half-life of carbon-xiv—5770 twelvemonth—and the measured ratio of 6 14C/half-dozen 12C, the age of the institute or creature remains can be calculated (Section 15.11). This procedure is known as radiocarbon dating.

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A Survey of Regulatory Aspects of Food Packaging

S. Ebnesajjad , in Plastic Films in Food Packaging, 2013

Section 179.21: Sources of Radiation Used for Inspection of Food, for Inspection of Packaged Food, and for Controlling Food Processing

Sources of radiations for the purposes of inspection of foods, for inspection of packaged food, and for decision-making food processing may exist safely used nether the following atmospheric condition:

a.

The radiations source is one of the following:

1.

X-ray tubes producing X-radiations from operation of the tube source at a voltage of 500   kV peak or lower.

2.

Sealed units producing radiation at energy levels of not more 2.two million electron volts (MeV) from 1 of the following isotopes: americium-241, cesium-137, cobalt-sixty, iodine-125, krypton-85, radium-226, and strontium-xc.

three.

Sealed units producing neutron radiation from the isotope californium-252 (CAS Reg. No. 13981-17-4) to mensurate moisture in nutrient.

4.

Machine sources producing X-radiations at energies no greater than 10   MeV.

5.

Monoenergetic neutron sources producing neutrons at energies non less than 1   MeV but no greater than 14   MeV.

b.

To assure safe use of these radiation sources:

1.

The label of the sources shall bear, in addition to the other information required by the Act:

i.

appropriate and accurate information identifying the source of radiation

ii.

the maximum energy of radiation emitted by Ten-ray tube sources

three.

the maximum energy of X-radiation emitted past machine source

iv.

the minimum and maximum energy of radiation emitted by neutron source

ii.

The label or accompanying labeling shall bear:

i.

adequate directions for installation and use

2.

a statement that no food shall be exposed to radiations sources listed in Paragraph (a) (one) and (two) of this section so as to receive an captivated dose in excess of 10   Gy

iii.

a argument that no food shall be exposed to a radiation source listed in Paragraph (a)(3) of this department so as to receive an absorbed dose in excess of 2   mGy

iv.

a statement that no food shall be exposed to a radiation source listed in Paragraph (a)(4) of this section so as to receive a dose in backlog of 0.5   Gy

v.

a statement that no food shall exist exposed to a radiation source listed in Paragraph (a)(5) of this department so as to receive a dose in backlog of 0.01   Gy

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