tenorm tenorm sources: summary table · geothermal energy waste scales (fact sheet) 10 132 254 oil...

TENORM Sources: Summary Table | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/sources_table.htm

1 of 3 9/14/2007 10:33 AM

TENORMRecent Additions | Contact Us | Print Version Search:

EPA Home > Radiation > Programs > TENORM >TENORM Sources: Summary Table

Radiation Home

Programs Home

TENORM Home

Basic Information

Frequent Questions

TENORM Sources

Working With Other Organizations

Regional TENORM Contacts

Glossary

Publications

Laws & Regulations

Guidance

Related Links

Radiation Home News Information Topics Programs Visitors'Center Site Map

TENORM Sources: Summary Table

The summary table below provides a range of reported concentrations, and average concentration measurements ofNaturally-Occurring Radioactive Materials (NORM) that become concentrated in various wastes and materials. Once the NORM isconcentrated or exposed by human activities, such as mining, it is classified as TENORM (Technologically-Enhanced, Naturally-Occurring Radioactive Materials).This is not a comprehensive list, as TENORM radiation is known to occur in manyother materials, but should provide a general sense of the hazardsposed by this class of radioactive substances.

Note:

Unless otherwise noted, the radiation level of each waste is shown in the units pCi/gram. For comparisonpurposes, the average level of radium in soil rangesfrom less than 1 to slightly more than 4 pCi/gram. "NA"indicates data is not available.

Source: Radiation Level [pCi/g]

low average high

Soils of the United States 0.2 NA 4.2

Geothermal Energy Waste Scales (fact sheet)

10 132 254

Oil and Gas Production Wastes (fact sheet)

Produced Water [pCi/l] 0.1 NA 9,000

Pipe/Tank Scale <0.25 <200 >100,000

Water Treatment Wastes (fact sheet)

Treatment Sludge [pCi/l] 1.3 11 11,686

Treatment Plant Filters NA 40,000 NA

Waste Water Treatment Wastes (fact sheet)

Treatment Sludge [pCi/l] 0.0 2 47

Programs

Programs Home

WIPP Oversight

Yucca Mtn. Standards

Mixed Waste

Federal Guidance

Naturally Occurring Radioactive Materials

Radon

Radionuclides in Water

SunWise

Rad NESHAPs

Regional Programs

MARSSIM

MARLAP

Cleanup: Technologies & Tools

Risk Assessment

Radiation Emergency Response

Clean Materials

Laboratories


2 of 3 9/14/2007 10:33 AM


Treatment Plant Ash [pCi/l 0.0 2 22

Aluminum Production Wastes (fact sheet)

Ore (Bauxite) 4.4 NA 7.4

Product 0.23

Production Wastes NA 3.9-5.6 NA

Coal and Coal Ash (fact sheet)

Bottom Ash 1.6 3.5-4.6 7.7

Fly Ash 2 5.8 9.7

Copper Production Wastes ( fact sheet)

0.7 12 82.6

Fertilizer Production Wastes (fact sheet)

Ore (Florida) 7 17.3-39.5 6.2-53.5

Phosphogypsum 7.3 11.7-24.5 36.7

Phosphate Fertilizer 0.5 5.7 21

Gold and Silver Extraction Wastes ( fact sheet)

Rare Earths (Monazite, Xenotime, Bastnasite) Extraction Wastes (fact sheet)

5.7 NA 3224

Titanium Production Wastes (fact sheet)

8.0 24.5

Rutile 19.7 NA

Ilmenite NA 5.7

Wastes 3.9 12 45

Uranium Mining Wastes (fact sheet)

Uranium Mining Overburden

low hundreds

Uranium In-Situ LeachateEvaporation Pond

3 30 3000

Solids 300

Zircon Extraction Wastes (fact sheet)


3 of 3 9/14/2007 10:33 AM


68

Wastes 87 1300

[Top of Page ]

Radiation Home · News · Topics · Information · Programs · Visitors' Center · Site Map

EPA Home | Privacy and Security Notice | Contact Us

Last updated on Friday, April 27th, 2007URL: http://www.epa.gov/radiation/tenorm/sources_table.htm

Aluminum Production Wastes | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/aluminum.htm

1 of 2 9/14/2007 10:34 AM


EPA Home > Radiation > Programs > TENORM > Aluminum Production Wastes

Radiation Home

Programs Home

TENORM Home

Basic Information

Frequent Questions

TENORM Sources



Glossary

Publications

Laws & Regulations

Guidance

Related Links


Aluminum Production Wastes

Waste muds created by the extraction of alumina from its ore, bauxite,may contain low levels of Naturally-Occurring Radioactive Materials (NORM) usually:

uraniumthoriumradiumtheir radioactive decay products.

The NORM becomes concentrated in the production wastes, which are then classified as TENORM (Technologically-Enhanced Naturally-Occurring Radioactive Materials).

Source Radiation Level [pCi/g] low average high

Ore (Bauxite) 4.4 NA 7.4

Product 0.23

Production Wastes NA 3.9-5.6 NA

Radiation in TENORM Summary Table

The only ore beneficiation operations performed at these bauxite mines include crushing and grinding. Water used fordust suppression, mine dewatering, and surface runoff results in the generation of a small volume of wastewater.This water is neutralized by lime and then discharged into nearby streams (EPA78a).

Bauxite refineries produce alumina (Al2O3) which is used primarily as a feedstock for the aluminum reduction industry.In 1989, five facilities in the United States engaged in domestic alumina production (EPA90). The locations and oresources for these facilities are shown in Table B.7-4. Thetotal annual production capacity for the domestic bauxite refining industry, as reported by these facilities, was approximately 4.9 million MT. The total reported 1988production of alumina was 4.1 million MT, which was about 84 percent of U.S. capacity (EPA90).

Bauxite ore is processed at an alumina plant using the Bayer or modified Bayer processes. Dried bauxite is mixed with a

Programs

Programs Home

WIPP Oversight


Mixed Waste

Federal Guidance


Radon


SunWise

Rad NESHAPs

Regional Programs

MARSSIM

MARLAP


Risk Assessment

Radiological Emergency Response

Clean Materials

Laboratories

Aluminum Production Wastes | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/aluminum.htm

2 of 2 9/14/2007 10:34 AM

caustic liquor in slurry tanks, transferred to heated digesters where additional caustic is added to dissolve the alumina from the bauxite. The alumina can then be furtherprocessed, transferred, or sold to another facility. The liquoris then pumped through settling tanks to remove the bauxite residue. This spent bauxite residue, called "red mud", isplaced in a tailings impoundment near the plant. Red mud insome plants is further processed to remove sodium aluminum silicate in the form of pure chemical grade alumina hydrates. This waste product is called "brown mud".Hydrated aluminum oxide is precipitated from the liquor and heated in rotary kilns to drive off water to produce aluminum oxide.

The refinery muds (both red and brown mud) dry to a solidwith very fine particle size (about 1 μm) and containsignificant amounts of iron, aluminum, calcium, and sodium.They may also contain trace amounts of elements, such asbarium, boron, cadmium, chromium, cobalt, gallium, lead,scandium, and vanadium, as well as NORM. The types andconcentrations of minerals present in the muds depend onthe composition of the ore and processing conditions. Thematerial is caustic and no secondary use has been made ofthe impounded muds. The EPA has identified elevatedarsenic (16μg/g) and chromium (374 μg/g) concentrations insome mud samples (EPA 90). However, muds might beused for land reclamation, for the construction of site damsor embankments, or as a feed material for other extractionprocesses because of the high iron content (20 to 50percent).



Last updated on Wednesday, November 15th, 2006URL: http://www.epa.gov/radiation/tenorm/aluminum.htm

Coal Mining Wastes and Coal Ash | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/coalandcoalash.htm

1 of 2 9/14/2007 10:34 AM


EPA Home > Radiation > Programs > TENORM >Coal Mining Wastes and Coal Ash

Radiation Home

Programs Home

TENORM Home

Basic Information

Frequent Questions

TENORM Sources



Glossary

Publications

Laws & Regulations

Guidance

Related Links


Coal Ash

Coal contains trace quantities of the naturally occurring radionuclides:

uraniumthoriumpotassiumtheir radioactive decay products including radium.

The presence of radium in coal is known to vary over two orders of magnitude depending upon the type of coal and region from which it has been mined.

When coal is burned, minerals including most of theradionuclides do not burn and as a result are concentrated in theash. Coal ash generally consists of fly ash, bottom ash, and boiler slags.

Utility and industrial boilers are estimated to generate about 61 million metric tons (MT) of coal ash per year. Of this total amount, nearly 20million MT are used in a variety of applications instead of being sent to disposal facilities, primarily:

additive in concretestructural fillroad construction.

The amount of ash generated during combustion is primarily dependent upon the mineral content of the coal and type of boiler.

The table below lists typical radiation levels in coal ash:

Wastes Radiation Level [pCi/g] low average high

Bottom Ash 1.6 3.5-4.6 7.7

Fly Ash 2 5.8 9.7


Programs

Programs Home

WIPP Oversight


Mixed Waste

Federal Guidance


Radon


SunWise

Rad NESHAPs

Regional Programs

MARSSIM

MARLAP


Risk Assessment


Clean Materials

Laboratories

Coal Mining Wastes and Coal Ash | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/coalandcoalash.htm

2 of 2 9/14/2007 10:34 AM



Last updated on Wednesday, November 15th, 2006URL: http://www.epa.gov/radiation/tenorm/coalandcoalash.htm

U.S. Geological Survey Fact Sheet FS-163-97 October, 1997

Introduction

Coal is largely composed of organic matter, but it isthe inorganic matter in coal—minerals and trace ele-ments—that have been cited as possible causes of health,environmental, and technological problems associatedwith the use of coal. Some trace elements in coal arenaturally radioactive. These radioactive elements includeuranium (U), thorium (Th), and their numerous decayproducts, including radium (Ra) and radon (Rn). Al-though these elements are less chemically toxic than othercoal constituents such as arsenic, selenium, or mercury,questions have been raised concerning possible risk fromradiation. In order to accurately address these questionsand to predict the mobility of radioactive elements dur-ing the coal fuel-cycle, it is important to determine theconcentration, distribution, and form of radioactive ele-ments in coal and fly ash.

Abundance of Radioactive Elements inCoal and Fly Ash

Assessment of the radiation exposure from coal burn-ing is critically dependent on the concentration of radio-active elements in coal and in the fly ash that remainsafter combustion. Data for uranium and thorium contentin coal is available from the U.S. Geological Survey(USGS), which maintains the largest database of infor-mation on the chemical composition of U.S. coal. Thisdatabase is searchable on the World Wide Web at:http://energy.er.usgs.gov/products/databases/CoalQual/intro.htm . Figure 1 displays the frequencydistribution of uranium concentration for approximately2,000 coal samples from the Western United States andapproximately 300 coals from the Illinois Basin. In themajority of samples, concentrations of uranium fall inthe range from slightly below 1 to 4 parts per million(ppm). Similar uranium concentrations are found in a vari-ety of common rocks and soils, as indicated in figure 2.Coals with more than 20 ppm uranium are rare in the UnitedStates. Thorium concentrations in coal fall within a similar1–4 ppm range, compared to an average crustal abundanceof approximately 10 ppm. Coals with more than 20 ppmthorium are extremely rare.

During coal combustion most of the uranium, tho-rium, and their decay products are released from theoriginal coal matrix and are distributed between the gas

phase and solid combustion products. The partitioningbetween gas and solid is controlled by the volatility andchemistry of the individual elements. Virtually 100 per-cent of the radon gas present in feed coal is transferredto the gas phase and is lost in stack emissions. In con-trast, less volatile elements such as thorium, uranium,and the majority of their decay products are almost en-tirely retained in the solid combustion wastes. Modernpower plants can recover greater than 99.5 percent of thesolid combustion wastes. The average ash yield of coalburned in the United States is approximately 10 weightpercent. Therefore, the concentration of most radioac-tive elements in solid combustion wastes will be approxi-mately 10 times the concentration in the original coal.Figure 2 illustrates that the uranium concentration of mostfly ash (10 to 30 ppm) is still in the range found in somegranitic rocks, phosphate rocks, and shales. For example,

900

780

660

540

420

300

180

60

≤1(1,2)

(2,3)(3,4)

(4,5)(5,6)

(6,7)(7,8)

(8,9)(9,10)

(10,11) (12,13)(11,12) (13,14) >15

URANIUM CONCENTRATION IN WHOLE COAL (ppm)

(14,15)

NU

MB

ER

OF

OB

SE

RVA

TIO

NS

Western United States

NU

MB

ER

OF

OB

SE

RVA

TIO

NS

≤1(1,2)

(2,3)(3,4)

(4,5)(5,6)

(6,7)(7,8)

(8,9)(9,10)

(10,11) (12,13)(11,12) (13,15)

>15

URANIUM CONCENTRATION IN WHOLE COAL (ppm)

NU

MB

ER

OF

OB

SE

RVA

TIO

NS

Illinois Basin

120

100

80

60

40

20

0

Figure 1. Distribution of uranium concentration in coal from twoareas of the United States.

Radioactive Elements in Coal and Fly Ash:Abundance, Forms, and Environmental Significance

the Chattanooga Shale that occurs in a large portion ofthe Southeastern United States contains between 10 and85 ppm U.

Forms of Occurrence of RadioactiveElements in Coal and Fly Ash

The USGS has a current research project to investi-gate the distribution and modes of occurrence (chemicalform) of trace elements in coal and coal combustionproducts. The approach typically involves (1) ultrasensitive chemical or radiometric analyses of particlesseparated on the basis of size, density, mineral or mag-netic properties, (2) analysis of chemical extracts thatselectively attack certain components of coal or flyash, (3) direct observation and microbeam analysis ofvery small areas or grains, and (4) radiographic tech-niques that identify the location and abundance of ra-dioactive elements.

Most thorium in coal is contained in common phos-phate minerals such as monazite or apatite. In con-trast, uranium is found in both the mineral and organicfractions of coal. Some uranium may be added slowlyover geologic time because organic matter can extractdissolved uranium from ground water. In fly ash, theuranium is more concentrated in the finer sized par-ticles. If during coal combustion some uranium is con-centrated on ash surfaces as a condensate, then thissurface-bound uranium is potentially more susceptibleto leaching. However, no obvious evidence of sur-face enrichment of uranium has been found in the hun-dreds of f ly ash particles examined by USGSresearchers.

The above observation is based on the use of fis-

sion-track radiography, a sophisticated technique forobserving the distribution of uranium in particles assmall as 0.001 centimeter in diameter. Figure 3 in-cludes a photograph of a hollow glassy sphere of flyash and its corresponding fission track image. Thediameter of this relatively large glassy sphere is ap-proximately 0.01 cm. The distribution and concen-tration of uranium are indicated by fission tracks,which appear as dark linear features in the radiograph.Additional images produced by USGS researchersfrom a variety of fly ash particles confirm the prefer-ential location of uranium within the glassy compo-nent of fly ash particles.

Health and Environmental Impact ofRadioactive Elements Associated WithCoal Utilization

Radioactive elements from coal and fly ash may comein contact with the general public when they are dispersedin air and water or are included in commercial products thatcontain fly ash.

The radiation hazard from airborne emissions of coal-fired power plants was evaluated in a series of studiesconducted from 1975–1985. These studies concludedthat the maximum radiation dose to an individual livingwithin 1 km of a modern power plant is equivalent to aminor, perhaps 1 to 5 percent, increase above the radia-tion from the natural environment. For the average citi-zen, the radiation dose from coal burning is considerablyless. Components of the radiation environment that im-pact the U.S. population are illustrated in figure 4. Naturalsources account for the majority (82 percent) of radia-tion. Man-made sources of radiation are dominated bymedical X-rays (11 percent). On this plot, the averagepopulation dose attributed to coal burning is includedunder the consumer products category and is much lessthan 1 percent of the total dose.

Fly ash is commonly used as an additive to con-crete building products, but the radioactivity of typi-cal fly ash is not significantly different from that ofmore conventional concrete additives or other build-ing materials such as granite or red brick. One ex-treme calculation that assumed high proportions offly-ash-rich concrete in a residence suggested a dose en-hancement, compared to normal concrete, of 3 percentof the natural environmental radiation.

Another consideration is that low-density, fly-ash-rich concrete products may be a source of radon gas.Direct measurement of this contribution to indoor radonis complicated by the much larger contribution from un-derlying soil and rock (see fig. 4). The emanation ofradon gas from fly ash is less than from natural soil of

Figure 2. Typical range of uranium concentration in coal, fly ash,and a variety of common rocks.

URANIUM CONCENTRATION (ppm)

Basaltic rock

U.S. coals

Common shales

Granitic rock

Fly ash = 10x U.S. coals

Phosphate rock

Black shales

0.1 1.0 10 100 1000

Figure 3. Photograph (left) of a hollow glassy fly ash particle (0.01 cm diameter) and its fission track radiograph (right). Uraniumdistribution and concentration are indicated by the location and density of dark linear fission tracks in the radiograph.

8%

COSMIC8%

TERRESTRIAL

INTERNAL11%

RADON55%

MAN-MAD

E18%

NAT

UR

AL

82%

CONSUMER

PRODUCTSOTHER <1%

MEDICALX rays

Nuclear

Medicine

4%

11%

3%

Figure 4. Percentage contribution of various radiation sourcesto the total average radiation dose to the U.S. population.

similar uranium content. Present calculations indicatethat concrete building products of all types contributeless than 10 percent of the total indoor radon.

Approximately three-fourths of the annual produc-tion of fly ash is destined for disposal in engineered sur-face impoundments and landfills, or in abandoned minesand quarries. The primary environmental concern asso-ciated with these disposal sites is the potential for ground-water contamination. Standardized tests of theleachability of toxic trace elements such as arsenic, sele-nium, lead, and mercury from fly ash show that the amountsdissolved are sufficiently low to justify regulatory classifi-cation of fly ash as nonhazardous solid waste. Maximumallowable concentrations under these standardized tests are100 times drinking water standards, but these concentrationlimits are rarely approached in leachates of fly ash.

The leachability of radioactive elements from fly ashhas relevance in view of the U.S. Environmental ProtectionAgency (USEPA) drinking water standard for dissolvedradium (5 picocuries per liter) and the proposed additionof drinking water standards for uranium and radon by

the year 2000. Previous studies of radioelement mobil-ity in the enviroment, and in particular, in the vicinity ofuranium mines and mills, provide a basis for predictingwhich chemical conditions are likely to influence leach-ability of uranium, barium (a chemical analog for ra-dium), and thorium from fly ash. For example,leachability of radioactive elements is critically influ-enced by the pH that results from reaction of water withfly ash. Extremes of either acidity (pH<4) or alkalinity(pH>8) can enhance solubility of radioactive elements.Acidic solutions attack a variety of mineral phases thatare found in fly ash. However, neutralization of acidsolutions by subsequent reaction with natural rock or soilpromotes precipitation or sorption of many dissolved el-ements including uranium, thorium, and many of theirdecay products. Highly alkaline solutions promote dis-solution of the glassy components of fly ash that are anidentified host of uranium; this can, in particular, increaseuranium solubility as uranium-carbonate species. For-tunately, most leachates of fly ash are rich in dissolvedsulfate, and this minimizes the solubility of barium (andradium), which form highly insoluble sulfates.

Direct measurements of dissolved uranium and ra-dium in water that has contacted fly ash are limited to asmall number of laboratory leaching studies, includingsome by USGS researchers, and sparse data for naturalwater near some ash disposal sites. These preliminaryresults indicate that concentrations are typically belowthe current drinking water standard for radium (5picocuries per liter) or the initially proposed drinking wa-ter standard for uranium of 20 parts per billion (ppb).

U.S. Department of the InteriorU.S. Geological SurveyFact Sheet FS-163-97

Dr. Robert B. Finkelman, U.S. Geological SurveyNational Center, Mail Stop 95612201 Sunrise Valley Drive, Reston, VA 20192703-648-6412; e-mail: [email protected]

Dr. Robert A. Zielinski, U.S. Geological SurveyDenver Federal Center, Mail Stop 973Denver, Colorado 80225(303) 236-4719; e-mail: [email protected]

For more information please contact:

Summary

Radioactive elements in coal and fly ash should notbe sources of alarm. The vast majority of coal and themajority of fly ash are not significantly enriched in ra-dioactive elements, or in associated radioactivity, com-pared to common soils or rocks. This observationprovides a useful geologic perspective for addressing so-cietal concerns regarding possible radiation and radonhazard.

The location and form of radioactive elements in flyash determine the availability of elements for leachingduring ash utilization or disposal. Existing measurementsof uranium distribution in fly ash particles indicate auniform distribution of uranium throughout the glassyparticles. The apparent absence of abundant, surface-bound, relatively available uranium suggests that the rateof release of uranium is dominantly controlled by therelatively slow dissolution of host ash particles.

Previous studies of dissolved radioelements in theenvironment, and existing knowledge of the chemicalproperties of uranium and radium can be used to predictthe most important chemical controls, such as pH, onsolubility of uranium and radium when fly ash interactswith water. Limited measurements of dissolved ura-nium and radium in water leachates of fly ash and innatural water from some ash disposal sites indicatethat dissolved concentrations of these radioactive ele-ments are below levels of human health concern.

Suggested Reading:

Tadmore, J., 1986, Radioactivity from coal-fired power plants: A review: Journal of Environmental Radioactivity,v. 4, p. 177–204.

Cothern, C.R., and Smith, J.E., Jr., 1987, Environmental Radon: New York, Plenum Press, 363 p.Ionizing radiation exposure of the population of the United States, 1987: Bethesda, Md., National Council on

Radiation Protection and Measurements, Report 93, 87 p.Swaine, D.J., 1990, Trace Elements in Coal: London, Butterworths, 278 p.Swaine, D.J., and Goodarzi, F., 1997, Environmental Aspects of Trace Elements in Coal: Dordrecht, Kluwer Academic

Publishers, 312 p.

DE

PA

RTM

ENT OF THE INTERIO

R

U.S

. GEOLOGICAL SUR

VE

Y

U.

S.

DE

PA

RTM ENT

ROI

RE

TNI

EHTFO

March 3,9481

Fertilizer Production Wastes | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/fertilizer.htm

1 of 3 9/14/2007 10:35 AM


EPA Home > Radiation > Programs > TENORM > Fertilizer Production Wastes

Radiation Home

Programs Home

TENORM Home

Basic Information

Frequent Questions

TENORM Sources



Glossary

Publications

Laws & Regulations

Guidance

Related Links


Fertilizer and Fertilizer Production Wastes

The phosphate ore used for the production of phosphate for fertilizers typically contains Naturally-Occurring Radioactive Materials (NORM), such as radium and other radionuclides and creates large amounts of radon.During the production of phosphoric acid, most of the radium ends up in process wastes, known as "phosphogypsum." Because the naturally-occurring radionuclides are concentrated in physphogypsum by human activity, it is a TENORM (Technologically-Enhanced Naturally-Occurring Radioactive Materials) waste. A small fraction of the radium accompanies the product, phosphoric acid, and ends up in commercial fertilizer.

Phosphate Fertilizer

The yearly consumption of fertilizers in the U.S. averagedclose to 5 million metric tons (MT) between 1984 and 1993. While phosphate fertilizers are not assumed to be waste, they do contain some of the naturally-occurring radium (Ra-226) found in phosphate ores.

The concentration of Ra-226 varies from five to 33 pico Curies per gram (pCi/g), depending upon the type of fertilizer blend and the origin of the phosphate rock. The averageRa-226 concentration in fertilizers used in this assessment ofthe impact of their use on soil concentrations is 8.3 pCi/g.

Fertilizer application rates are known to vary depending upon the type of crops and soils. A typical phosphate fertilizerapplication rate is about 40 kg per hectare. Fertilizers areavailable in over 100 different blends with varying concentrations of nitrogen, phosphorus, and potassium. The resulting increase in soil concentrations of Ra-226 isonly on the order of 0.002 pCi/g for 20 years of repeated fertilizer applications. By comparison, natural soils contain radium in concentrations ranging from 0.1 to 3 pCi/g.


Phosphate Fertilizer 0.5 5.7 21

Fertilizer Production Wastes

Phosphogypsum is a the primary byproduct of the wet-acid

Programs

Programs Home

WIPP Oversight


Mixed Waste

Federal Guidance


Radon


SunWise

Rad NESHAPs

Regional Programs

MARSSIM

MARLAP


Risk Assessment


Clean Materials

Laboratories


2 of 3 9/14/2007 10:35 AM

process for producing phosphoric acid from phosphate rock.It is largely calcium sulfate and has been given the namephosphogypsum. (Gypsum is the common trade name for calcium sulfate, a common building material.) Phosphate production generates very large volumes ofphosphogypsum, which is stored in huge piles called "stacks" that cover hundreds of acres in Florida andother phosphate-processing states.

The table below shows the range of activity in fertilizer production wastes:


Phosphate Ore (Florida) 7 17.3-39.5 6.2-53.5

Phosphogypsum 7.3 11.7-24.5 36.7


Since there are large quantities of phosphogypsum waste, the industry encourages its use in order to minimize the disposal problem. Past and current uses of phosphogypsuminclude:

agricultural: fertilizer and soil conditionerbackfill for road constructionconcrete additive.

The most use of phosphogypsum is in agricultural applications.

Agricultural

Phosphogypsum has been used in agriculture as a source of calcium and sulfur for soils that are deficient in these elements. When the phosphogypsum is used as a fertilizer, itis simply spread on the top of the soil. When used for pH adjustment or sediment control, it is tilled into the soil.

The activity of phosphogypsum used for agricultural purposes may not exceed 10 pCi/g. An estimated 221,000 metric tons of phosphogypsum are taken from the phosphogypsum stacks and used in agriculture each year (. There is no limitation on the amount of material that can be applied and farmers do not have to maintain certificates or application records.

Road Construction

Phosphogypsum was used previously in road construction.Currently, this use is banned under the EPA final rule issuedon June 3, 1992, which amends 40 CFR 61 Subpart R (EPA92).

New Uses

In response to the need for new ways to make use of


3 of 3 9/14/2007 10:35 AM

phosphogypsum, EPA has provided a process by whichresearchers may apply for approval from EPA for new uses. In addition, the state of Florida has created an independentstate research agency, Florida Institute of Phosphate Research (FIPR) charged with investigating ways tominimize adverse environmental impacts of the phosphateindustry.

Resources

Rad-NESHAPs, Subpart R: Radon from Phophogypsum StacksThis site provides information on EPA's National Emission Standards for Hazardous Air Pollutants: Radionuclides that apply to radon emissions from phosphogypsum stacks. It also provides information on the formation of phosphogypsum, the stacks, and potential uses for thematerial.



Last updated on Wednesday, November 15th, 2006URL: http://www.epa.gov/radiation/tenorm/fertilizer.htm

Geothermal Energy Production Waste Scales | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/geothermal.htm

1 of 2 9/14/2007 10:34 AM


EPA Home > Radiation > Programs > TENORM > Geothermal Energy Production Waste Scales

Radiation Home

Programs Home

TENORM Home

Basic Information

Frequent Questions

TENORM Sources



Glossary

Publications

Laws & Regulations

Guidance

Related Links


Geothermal Energy Production Waste Scales

Using geothermal energy requires drilling deep holes (boreholes)andinserting pipes for pumping high-temperature fluids from the ground.The rocks that contain the high-temperature fluids may also containminerals, which tend to form a scale inside the pipes and productionequipment. If the rocks also contain radionuclides, such as radium,the mineral scale, production sludges, and waste water will containTENORM.

Geothermal energy currently makes a relatively minor contribution to total U.S. energy production. The primary geothermal developmentsites in the U.S. are the Geysers, in Sonoma County in northern California, and the Imperial Valley in southern California. The onlysignificant TENORM wastes from geothermal power production are the solid wastes originating from the treatment of spent brines such as in Imperial Valley. The hot saline fluids from geothermal reservoirsin that area may have a dissolved solids content approaching 30 percent by weight. The estimated annual generation rate ofgeothermal energy production waste is 54 thousand metric tons.

Because of unsuitable physical characteristics, solid geothermal wastes are not reused, but disposed of in solid waste landfills. A few facilities are also considering process of these wastes to extract valuable minerals (gold, sliver, and platinum).

The table below shows the estimated average activity in geothermal wastes, based on data from southern California geothermal power production facilities:

Wastes Radiation Level [pCi/g] low average high

Geothermal Energy Waste Scales

10 132 254


Programs

Programs Home

WIPP Oversight


Mixed Waste

Federal Guidance


Radon


SunWise

Rad NESHAPs

Regional Programs

MARSSIM

MARLAP


Risk Assessment


Clean Materials

Laboratories

Geothermal Energy Production Waste Scales | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/geothermal.htm

2 of 2 9/14/2007 10:34 AM



Last updated on Wednesday, November 15th, 2006URL: http://www.epa.gov/radiation/tenorm/geothermal.htm

Oil and Gas Production Wastes | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/oilandgas.htm

1 of 2 9/14/2007 10:33 AM


EPA Home > Radiation > Programs > TENORM > Oil and Gas Production Wastes

Radiation Home

Programs Home

TENORM Home

Basic Information

Frequent Questions

TENORM Sources



Glossary

Publications

Laws & Regulations

Guidance

Related Links


Oil and Gas Production Wastes

The rocks that contain oil and gas deposits often contain water aswell. The water dissolves minerals and radionuclides, such as radium,that are in the rocks. (These Naturally Occurring Radioactive Materials are commonly referred to as, NORM.) Radium and other radionuclides and their radioactive decay products becomeconcentrated in production wastes:

pipe scale that tends to form inside oil and gasproduction pipes and equipmentlarge volumes of waste watersludges that accumulate in tanks or pits.

These waste are classified as TENORM (Technologically-Enhanced, Naturally-Occurring Radioactive Materials).

The types of waste generated by the petroleum industry include pipe scale, sludge, and equipment or components contaminated with radium. It is estimated that the industry generates about 150,000cubic meters or 260,000 metric tons of such waste yearly.

Field surveys have shown that petroleum pipe scale may have very high Ra-226 concentrations, in some cases more than 400,000 pCi/g.Some of this waste is retained in oil and gas production equipment, while some of the scale and sludge is presently being removed and stored in drums. The industry disposes of scale and sludge wastesremoved from oil and gas production equipment and also discards associated contaminated components.

The table below shows the range of activities in these wastes:

Wastes Radiation Level [pCi/g]low average high

Produced Water [pCi/l] 0.1 NA 9,000

Pipe/Tank Scale <0.25 <200 >100,000


Programs

Programs Home

WIPP Oversight


Mixed Waste

Federal Guidance


Radon


SunWise

Rad NESHAPs

Regional Programs

MARSSIM

MARLAP


Risk Assessment


Clean Materials

Laboratories

Oil and Gas Production Wastes | Radiation Protection | US EPA http://www.epa.gov/radiation/tenorm/oilandgas.htm

2 of 2 9/14/2007 10:33 AM



Last updated on Wednesday, November 15th, 2006URL: http://www.epa.gov/radiation/tenorm/oilandgas.htm

Thorium Containing Welding Rod (1990s) http://www.orau.org/ptp/collection/consumer%20products/weldingrod.htm

1 of 3 9/14/2007 10:32 AM

Thorium Containing Welding Rod (1990s)General

Thoriated welding rods are used as electrodes intungsten inert gas (TIG) welding in which the rod serves as a "nonconsumable" electrode. The rod isactually consumed during use, but it does not act as a filler that binds two pieces of metal together. Therate of consumption is approximately 0.1 to 0.3mg/minute for typical currents but it can be as highas 50 to 60 milligrams per minutes for the maximum rated currents. This consumption probably involvesvolatilization and the loss of tiny droplets at theelectrode tip. Because TIG welding is expensive, itsis limited to those situations that require high qualityresults (e.g., the aircraft and petrochemical industries).

By weight, the rods are usually 1 or 2 % thoriumoxide (thoria) although higher concentrations, up to 4 %, have been used. The rods are color coded toindicate the thoria content: yellow indicates 1 %, andred indicates 2 %. The color usually appears as aband at one end of the rod (like that in the photo tothe right). While they range from 0.25 to 6.35 mm indiameter and 7.6 to 61 cm long, a “typical” rodwould be about 2.4 mm in diameter, 15 cm long, andcontain 0.23 grams of thorium. Estimates over thelast two decades put the annual production at 1 to 5million electrodes.

Thorium is added to the tungsten because it increasesthe current carrying capacity of the electrode and itreduces contamination of the weld. In addition, it iseasier to start the arc and the latter is more stable.

The radiological concern is the inhalation of airborne thorium. Thorium gets into the air because of thevolatilization discussed earlier and the grinding that is necessary to put a point on the electrode prior to use.As a result of this concern, it is expected that the thorium in the rods will eventually be replaced bylanthanum or cerium oxide.

Airborne Thorium Concentrations

During welding operations, Ludwig et al measured thorium concentrations of < 7 x 10-9 to 5 x 10-6 uCi/m3 with a geometric mean of 3 x 10-8 uCi/m3. The concentrations measured during AC welding operationswere approximately 30 times those measured during DC welding.

Vinzents et al. measured a respirable concentration of 2 x 10-5 uCi/m3 during the grinding of rods with a 4


2 of 3 9/14/2007 10:32 AM

% thorium content (the respirable fraction was 0.3). The conditions selected for the study were a “worstcase” scenario. Ludwig et al reported an airborne concentration of 5 x 10-6 uCi/m3 during the grinding.Crim and Bradley reported 6.3 x 10-7 uCi/m3 while Jankovic et al reported 1.4 x 10-6 uCi/m3 . Based on this data, NUREG-1717 concluded that a typical concentration during grinding was 2.3 x 10-6 uCi/m3.

Dose Estimates

Detailed dose estimates are described in NUREG-1717. The conclusion was that the maximum individualdoses resulted from routine welding and grinding operations. The estimated doses due to transportation anddistribution were relatively small.

1. Doses from grinding.

The grinding of the rod to form a pointed end can take anywhere from 20 to 60 seconds depending on theskill of the grinder. For welders that grind their own rods, this can take a minute or even longer. Individualswho specialize in this activity can complete the task much quicker. At a large facility, e.g., with 50 welders,a grinder might handle as many as 150 rods per day (ca. 3 per day per welder). For the purpose of the calculations, NUREF-1717 assumed that the particle size AMAD was 1 um.

An individual welder sharpening his own rods was estimated to receive 20 mrem per year. This would be reduced by a factor of ten or so if a local exhaust system was used.

A dedicated grinder sharpening rods for 200 hours per year without the benefit of a local exhaust systemwas estimated to receive approximately 800 mrem.

2. Doses from Welding Operations

As NUREG-1717 acknowledges, any estimation of the dose due to welding operations is highly speculative.Assumptions have to be made about the amount of thorium becoming airborne, the amount of time spentwelding, the effect of the welder’s mask, the ventilation rate, the size distribution of the particulates, etc.

Assuming that 1000 hours per year were spent in actual welding operations, NUREG-1717 estimated thatthe dose would be 20 mrem per year for DC operations and 500 mrem per year for AC operations. Theseestimates assume that no local exhaust system was used. Should local exhaust be employed, the estimateddoses would be a factor of ten or so lower. The external exposure due to beta particles and gamma rays wasdetermined to be an insignificant fraction of the dose due to inhalation.

3. Dose from Carrying Welding Rods in Pocket

The estimated effective dose equivalent to an individual carrying three thoriated welding rods (0.9 gthorium) in a shirt pocket for 2000 hours (40 hrs/week x 50 weeks/year) was 8 mrem..

Pertinent Regulations

10 CFR 40.13 Unimportant quantities of source material (2003)

(c) Any person is exempt from the regulation in this part and from the requirements for a license set forth insection 62 of the Act to the extent that such person receives, possesses, uses, or transfers: . . .

(1) Any quantities of thorium contained in . . . (iii) welding rods,

References


3 of 3 9/14/2007 10:32 AM

Breslin, A.J., and Harris, W.B. Use of Thoriated Tungsten Electrodes in Inert Gas Shielded Arc Welding –Investigation of Potential Hazard. American Industrial Hygiene Association Quarterly 13 (4); 1952.

Ludwig, T., Schwab, D., Seitz, G., and Siekmann, H. Intakes of Thorium While Using Thoriated TungstenElectrodes for TIG Welding. Health Physics 77 (4): 462-469; 1999.

NCRP. Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources.NCRP Report No. 95; 1987.

Nuclear Regulatory Commission. Systematic Radiological Assessment of Exemptions for Source andByproduct Materials. NUREG-1717. June 2001.

Radioactive Consumer Products Museum Directory

Last updated: 07/25/07 Copyright 1999, Oak Ridge Associated Universities

tenorm tenorm sources: summary table · geothermal energy waste scales (fact sheet) 10 132 254 oil...

Documents