radiochemistry webinars actinide chemistry series ... · –osha hazard alert –mined in ia, wi...

National Analytical Management Program (NAMP)

U.S. Department of Energy Carlsbad Field Office

In Cooperation with our University Partners

Radiochemistry Webinars Environmental/Bioassay Radiochemistry Series

Unconventional Drilling/Hydraulic Fracturing and

Natural Radioactivity

Meet the Presenters… Michael K. Schultz, PhD

Dr. Schultz is an Associate Professor in the Department of Radiology at the University of Iowa, with secondary appointments in the Free Radical and Radiation Biology; Human Toxicology; and Medical Scientist Training Programs. Dr Schultz also co-directs the Radiochemistry Program in the Department of Chemistry. His research interests in environmental radioactivity focus on naturally occurring radioactive material (NORM) associated with liquid and solid waste resulting from unconventional drilling and hydraulic fracturing. This year, Dr. Schultz has been invited to speak on this topic at the American Chemical Society National Meeting, the National Environmental Monitoring Conference, and ASTM International. A recent article (Nelson et al., Env Sci Techn Let, March 11, 2014) was selected for an ACS Editor’s Choice Award and the article, first authored by PhD graduate student and Presidential Fellow Andrew Nelson, is featured on the cover of the journal. Funded by the University of Iowa’s Center for Health Effects of Environmental Contaminants, Dr. Schultz's laboratory (with collaborator Tori Forbes, Department of Chemistry) has begun field studies on the environmental geochemical behavior of NORM in natural surface water systems impacted by unconventional drilling and hydraulic fracturing operations and waste treatment facilities. Mike earned his PhD in Oceanography at Florida State University, studying the environmental radiochemistry of anthropogenic and natural radionuclides in terrestrial and aquatic systems.

2

Andy Nelson, MS Andy Nelson earned a B.A. in biochemistry from the University of Colorado in 2009 and an M.S. in environmental engineering from the Colorado School of Mines in 2010. As a research assistant in the Department of Molecular, Cellular, and Developmental Biology (MCDB) at the University of Colorado, Mr. Nelson studied free radical signaling mechanisms relevant in aging and tumor progression. In 2012, Andy was awarded the University of Iowa Presidential Graduate Fellowship to pursue a PhD in the Interdisciplinary Human Toxicology Program. He is currently a doctoral candidate under the mentorship of Dr. Schultz, with whom he studies radioactivity associated with unconventional drilling (hydraulic fracturing and horizontal drilling) of shale gas. Much of Mr. Nelson’s work to date has focused on developing methods that are suitable for monitoring levels of naturally occurring radioactive materials (NORM) present in wastes generated by unconventional natural gas exploration. Andy’s research has helped develop partitioning models that will be used in the development of sound waste management strategies for solid and liquid wastes generated by unconventional drilling.

Radioactivity and Unconventional

Drilling Michael K. Schultz, PhD Andrew W. Nelson, MS

National Analytical Management Program (NAMP)

U.S. Department of Energy Carlsbad Field Office

TRAINING AND EDUCATION SUBCOMMITTEE

C:/Documents and Settings/medinad/Desktop/Plutonium, Element 54/Paviet-Hartmann Lead In Slides.pptx#2. Slide 2

Disclaimer

Certain products and manufacturers are mentioned during this presentation for the purpose of fostering understanding.

Reference to these commercial products and manufacturers in this presentation does not constitute recommendation or endorsement of the products.

4

5

Radiochemistry

Unconventional Drilling Hydraulic Fracturing

Outline

• Background on “fracking”? – Why, Where, What and How

• Source of radioactivity

• Geochemical considerations

• Methods to detect NORM in flowback

• Considerations for: – Liquid waste – Solid waste

• Future research needs

6

Increasing Global Energy Demand

7

http://www.eia.gov

Unconventional Drilling Rapidly Expanding in U.S.

8

http://www.eia.gov

Major U.S. Natural Gas Plays

9

http://www.eia.gov

Global Shale Formations

10

http://www.eia.gov

What is Fracking?

11

“Fracking” =

Hydraulic Fracturing ≈

Unconventional Drilling

5 Major Stages of Hydraulic Fracturing

12

http://www2.epa.gov/hfstudy/hydraulic-fracturing-water-cycle

Stage 1: Water Acquisition

• Water Usage – Up to 55,000 m3 (15 million

gallons) per well

• Concern – Straining water resources

• Arid states concerned • Growing concern elsewhere

– Unknown contribution to radioactivity • Recycling fluids?

13

Stage 2: Chemical Mixing

14

• Caustics and toxics –Hydrochloric acid –Proprietary chemicals –Antimicrobials –Unknown interactions with NORM

• Sand –Crystalline silica –OSHA hazard alert –Mined in IA, WI

https://www.osha.gov/dts/hazardalerts/hydraulic_frac_hazard_alert.html

Stage 3: Well Injection

15


Radioactive Solid Waste 16

• Bit Cuttings

– 250,000 kg/well

– Trucks turned away from landfills

– Radiation alarms set off

https://www.rigzone.com/training/insight.asp?insight_id=294&c_id=24

http://www.post-gazette.com/local/marcellusshale/2013/08/22/Marcellus-Shale-waste-trips-more-radioactivity-alarms-than-other-products-left-at-landfills/stories/201308220367

Stage 4: Flowback/Produced Water 17

Thousands of cubic meters (millions of gallons) produced fluids per well

Radioactive Produced Fluids

18

• Documented High Levels of Ra

> 670 Bq/L 226Ra

(18,000 pCi/L)

> 95 Bq/L 228Ra

(2,500 pCi/L)

Stage 5: Disposal/Treatment of Waste 19

• Solids (250000 kg/well) – Municipal landfills • Radiation alarms

– Hazardous waste landfills

• Fluids – POTWs – Industrial treatment

facilities – Deep surface injection – Recycling – Transportation

considerations • Trucking • Barges?

Where does the radioactivity come from?

20

1. Radioactive Tracers – Most common are gamma emitters • 46Sc, 140La, 56Mn, 24Na, 124Sb, 192Ir, 99Tcm, 131I, 110Agm, 41Ar, 133Xe

– Measure flow rates & inter well connections – Short half-lives (hours to days)

2. Naturally Occurring Radioactive Materials – Present in the formation • 238U (uranium) series • 232Th (thorium) series • 235U (actinium) series

– Long half-lives, decay products, differing chemistries

http://www-pub.iaea.org/MTCD/publications/PDF/Pub1171_web.pdf

Marine Black Shales

21

http://pubs.usgs.gov/pp/0356c/report.pdf

http://written-in-stone-seen-through-my-lens.blogspot.com/2011/01/lace-crab.html

• Ancient marine environments

• High organic matter

• High associated U levels

General Shale Geochemical Characteristics 22

• Reducing environment (anoxic)

• Microbial sulfate reduction

– Low sulfate concentrations

• High salt

– Evaporite

– Unclear where all the salt from Marcellus originates

General Chemistry of Uranium Series

23

http://metadata.berkeley.edu/nuclear-forensics/Decay%20Chains.html

• U redox sensitive (+6 soluble, +4 immobile)

• Pa particle reactive

• Th particle reactive

• Ra soluble in low-sulfate (SO42-) brine

• Rn short-lived gas

• Po isotopes short-lived, redox sensitive, particle reactive

• Bi isotopes short-lived, supported by Pb isotopes

• Pb isotopes short-lived (exception 210Pb, which can accumulate in brine)

Case Study — Marcellus Shale

• One of the largest natural gas plays in the U.S.

• Underlies multiple states

• Regulation differs state to state

– NY “fracking’ moratorium

– OH, WV, PA allow

24

http://www.marcellus.psu.edu/

http://www.eia.gov/todayinenergy/detail.cfm?id=14091

NORM in the Marcellus Shale

25

http://www.eia.gov/todayinenergy/detail.cfm?id=14091

• Marine Black Shale

• Devonian Age

– 350-400 million yrs old

• Radioactive decay products assumed in secular equilibrium

Lessons from NORM Analysis of Marcellus Flowback

26

Matrix

27

Ba:Ra ≈ 109

Analyte Concentration (mg/L)

Chloride 146,667

Strontium 36,333

Sodium 29,333

Calcium 13,000

Barium 9,000

Magnesium 853

Manganese 3

Iron 43

Total Solids 277,666

Suspended Solids 783

Scheme for Analysis

Gamma Emitters: 228Ac, 226Ra, 224Ra, Pb and Bi isotopes, 235U, 208Tl, 234Th

Special Case:

226Ra, 222Rn

Alpha Emitters (excluding Ra): Po Isotopes, U isotopes, 228Th, 230Th, 232Th

28

Liquid Scintillation

Alpha Spec

HPGe Gamma Spec

Rad7

29

BaSO4 MnO2

610 B

q/L

670 B

q/L

Wet Chemical Methods

Not Effective

Analysis of Alpha Emitters

30

• Isotope dilution alpha spectrometry

– U

– Th

– Po

• Wet chemistry effective

– Pre-concentrations (ex: MnO2, FeOH3)

– Chromatography (ex: Eichrom® Resins)

– Microprecipitations (ex: CeOH3)

Simplifying the Matrix (MnO2)

31

0.25 – 1L FBW

Precipitate Chromatography

Complex

Digest Wash/Dissolve

Add Tracers Add KMnO4

Method Summary

• Polonium Recoveries (81 ± 9 %)

Autodeposition slow

Considered alternatives

• Uranium Recoveries (63 ± 8 %)

• Thorium – Recoveries (85 ± 9 %)

32

Ingrowth of 210Pb and 210Po in Flowback

33

*H. Bateman, Proc. Cambridge Philos. Soc. 1910 (15) 423-427

Uranium—Low Levels in Flowback

34

*[226Ra= 670 Bq/L]

35

Ingrowing 228Th in Flowback

36

Partitioning Model

Th-234

U-238

Daughter recoil

U(IV)-234

Th-230 Ac-228 Th-228

Ra-224

Daughter recoil Insoluble

Thorium Series

Uranium Series

Brine

Rock

Rock

Th-232

Pb-210

Fissure

U-234

Ra-226

Rn-222

Rn-222

Po-210 ?

Ra-228

Th-234

U-238

Daughter recoil

U(IV)-234

Th-230

Ra-226

Ac-228 Th-228

Ra-224

Daughter recoil Insoluble

Thorium Series

Uranium Series

Brine

Rock

Rock

Th-232

Pb-210

Fissure

Rn-222

Po-210

Rn-222

U-234

Ra-228

The Big Picture 37

38

Importance of Partitioning Decay Product Ingrowth in Flowback

*closed system

39

Ingrowth Occurs for Many Years

Special Considerations for Liquid Waste

• Enriched in Ra isotopes – Can lead to Ra contamination

• Rn generators – Inhalation hazards?

• Ra decay products ingrowth unavoidable

• Ra decay products have different chemistry – Ra treatments (ex: sulfate

precipitations) • May not remove decay products • 210Pb, 210Po, and 228Th of concern • Difficult to detect

40

41

Liquid Waste in Marcellus Region

• Industrial Treatment

– Occurs in PA, WV, OH

– Ra decay products

– Occupational exposure?

– Surface Water Contamination?

• Underground Injection & Recycling Flowback

– Ra decay products

– Occupation exposure?

– Unclear fate of NORM after injection

onlinelibrary.wiley.com/doi/10.1002/wrcr.20096/pdf

Special Considerations with Solid Waste

• Bit cuttings coming from reduced environment to oxidizing surface –Increase mobility of select

radionuclides • U4+

U6+ • Po speciation? • Fe and Mn adsorptive surfaces may

change

• 234U, 210Po, 232Th, 230Th, 228Th not detected by gamma-ray meters –Note: 234U enriched by

alpha-recoil, thus cannot assume 1:1 234U:238U activity

42

http://www.theguardian.com/environment/2011/jun/27/water-shortages-threaten-renewable-energy

• Billions of kgs bit cuttings

• Interstate transfer

• Most bit cuttings go to landfills

• Emerging reports of radioactivity alarms at landfills

– Unclear which isotopes

– Unclear what level of alpha emissions

• Concerns of radioactivity leaching

Solid Waste in Marcellus Region

43

http://www.triplepundit.com/2014/04/west-virginia-landfill-wastewater-shows-elevated-radioactivity-due-fracking-authorities-report/

Future Research Needs

On-going studies in the Schultz and Forbes Labs:

Other important questions:

• Bench studies on the behavior of NORM in bit cuttings from Marcellus Shale

• Field studies on the environmental fate and equilibrium status of Ra decay products

• What levels of 222Rn are released from landfills and wastewater treatment facilities accepting unconventional drilling waste?

• What is the potential/extent of bioaccumulation of NORM from unconventional drilling waste?

Thank you! Questions? • State Hygienic Laboratory at UIowa

– Dr. Michael Wichman – Marinea Mehrhoff – Dustin May

• Schultz and Forbes Labs (UIowa) – Dr. Michael K Schultz – Dr. Tori Z Forbes – Eric Eitrheim – Andrew Knight

• EMS – Robert Shannon – Dr. Robert Litman

45

Questions and Answers

Question and Answer #1

• With the high level of salts in Marcellus shale, will K40 NORM also have high level of radioactivity to consider?

• Certainly 40K will be present in formations with high levels of K. We do not focus in the study of 40K as directly decays to stable isotopes. Consequently partitioning processes of 40K will not result in apparent increases of radioactivity like observed for the Ra decay series. Our gamma spectrometry results suggest that levels of 40K are 10 Bq/L, approximately 2 orders of magnitude lower than the levels of 226Ra (670 Bq/L)

Question and Answer #2 • The reference that was mentioned from USGS should be on a bibliography if not

part of the handout. The links for some are accessed by clicking on them. There are some interesting follow on discussions well beyond this topic. How would we add these to the potential that might be studied by these researchers? One example is that when the flowback water is received at a POTW, the facility, which typically does not understand the chemistry for the radionuclides has several issues to deal with and these include: 1) Buildup of precipitates within the facility and occupational radiation exposure of personnel. 2) Disposal of liquid and solid wastes. The liquids need to meet Clean Water Act concentration guidelines and the solids that go to a landfill need to meet disposal (Form U) requirements.

• The USGS manuscripts may be accessed at the following links: Rowan et al. 2011 http://pubs.usgs.gov/sir/2011/5135/ Swanson 1961 http://pubs.er.usgs.gov/publication/pp356C We agree there are many potential questions to be addressed about occupational exposures. We cannot comment on the policies regarding waste management of liquid and solid wastes; however, we would like to point out that solid and liquid wastes from the oil and natural gas industry (as well as NORM wastes) may be regulated differently from state to state.

http://pubs.usgs.gov/sir/2011/5135/

http://pubs.usgs.gov/sir/2011/5135/

http://pubs.er.usgs.gov/publication/pp356C




• There are a number of companies that are receiving permits to evaluate, handle and then authorize NORMs and TENORMS for disposal. Companies like Austin Masters Services from Pottsville, PA, state that they have methods to evaluate radioactivity in closed trucks and clear them for processing and disposal. In your professional opinion, do technologies exist to evaluate radionuclides in complex, enclosed wastes such as drill cuttings and produced water?

• We suspect that these wastes are monitored by the gamma emissions. To truly quantitate the levels of gamma emitters in these wastes, an assumption about the distribution of the radionuclides in the wastes (i.e., are the wastes sorbed to the inside surface of the truck or equally distributed) and the geometry (i.e. is the truck square or cylindrical) of the truck is required.

Question and Answer #4 • How many tons of drill cuttings are generated for a single horizontal

well? How much liquid waste is generated during this stage? Is the crystalline silica more hazardous once it is covered with chemicals used in hydraulic fracturing? Should we be concerned about hazards other than simple silicosis?Why are they concentrating on flow back when it appears that produced water and drill cuttings seem to be more problematic?

• The number of kilograms (not sure which unit of ton you are referring to: metric? Short?) from each well will vary. Some estimates suggest on average 250,000 kg per well, though keep in mind this will depend on a number of factors including the length of the well, the width of the well, the properties of the formation(s), etc. Liquid wastes greatly vary from well to well, depending on a multitude of factors. We hesititate to give a firm number as these number are so variable. For more information on silicosis as it relates to hydraulic fracturing, please visit https://www.osha.gov/dts/hazardalerts/hydraulic_frac_hazard_alert.html. Crystalline silica is not our area of expertise, but keep in mind that without exposure, there is no health risk. Exposure to crystalline silica is mostly an inhalation hazard.




• As a student of atmospheric science, I would like to know if you know of any work that has been done regarding radioactive materials in the atmosphere through natural gas? What questions would you want to see addressed in this area?

• Fallout of Pb-210/Po-210 by Rn-222 gas in the atmosphere is a well known phenomenon. It will be interesting to see what levels of Rn-222 are released during flaring of natural gas from shale reservoirs.


• How does the incidence of radioactive materials in shale deposits compare to other kinds of excavations?

• Shale deposits and other organic rich formations appear to have higher levels of U due to various enrichment processes. This is advantageous to natural gas/oil exploration by use of gamma-ray logs. Solid wastes from these organic rich formations may be enriched in NORM. There are many excavations from other types of formations, however, the incidence of NORM in these other formations is outside our realm of expertise.


• Do the folks that work in the industrial wastewater treatment facilities that receive flowback wastes have their personal dose monitored?

• We cannot comment on whether personal dose meters are worn; however, we suspect chronic inhalation of Rn-222 and its alpha-emitting decay products will pose a greater exposure risk than gross gamma or beta exposures.

Question and Answer #8 • A very valuable point regarding 212Pb. It is controlled by 224Ra not

228Ra. This issue is important to clarify so that misrepresentation does not occur. What is of direct interest to this issue: what are the ratios of 224Ra to 228Ra in the brines? In drinking waters, on rare occasion, 224Ra can be substantially enriched by factors 2X, 3X, or even slightly more.

• We found that levels of 228Ra (measured by 228Ac) were 76 Bq/L one week after receipt in the lab. Levels of 224Ra by direct measurement were complicated by interferences from Pb/Bi isotopes; however, the 224Ra decay product 212Pb was 2.4 Bq/L. Assuming 212Pb were in equilibrium with 224Ra (i.e., no disequilibrium introduced by 220Rn), this would suggest levels of 224Ra were significantly lower than those of 228Ra. Not knowing the exact date when the sample was extracted from the formation, it is difficult to time correct the ratios of 224Ra to 228Ra at the time of extraction. Thus, we cannot comment (particularly due to the short half-life of 224Ra), what the ratio was at the time of extraction. This is a topic that warrants further investigation as it could also potentially be used as a forensics tool (like the 228Ra/228Th ratios) to determine when fluids were released from a well.


• The partitioning is dependent on the pH and red-ox potential of the fluid in the horizontal part of the drilling. How can you get an estimation about the conditions down there? sampling will change the parameters, or do you have sampling possibilities without change in pressure or temperature?

• You raise some great points. We did not collect this sample, so we are interpreting it with the information that we have available. Certainly more investigations are warranted to determine how pH, redox, temperatures, and pressures change over time and how this will affect the partitioning of NORM.

Question and Answer #10 • What are the observed activity concentration ranges in all of your samples

and approximate distributions of values among all samples for: - Ra-226 - Ra-228 - Pb-210 - Po-210 - Rn-222

• Levels of Ra-226 were approximately 670 Bq/L. For more information on this topic, please refer to the following article: Nelson et al. “Matrix Complications in the Determination of Radium Levels in Hydraulic Fracturing Flowback Water from Marcellus Shale”Environmental Science & Technology Letters 2014 1 (3), 204-208 For Ra-228, please refer to comment 8. For levels of Pb-210, Po-210, and Rn-222 we hesitate to report a single value as these are moving targets. Initially Po-210 and Pb-210 were below detection limits, but over time they steadily increase in the sample as predicted by the Bateman equation. Rn-222 can be removed from the sample, but it will grow-in at a rate related to its own half-life until all the 226Ra has been removed or decayed away.


• What kind of concentration factors of NORM are you seeing with recycling of fracking water?

• We have not done any analyses of recycled flowback water. This is certainly a topic we find very interesting and one that warrants further investigation.


• How much does the chemistry of different shale formations affect the partitioning of the various NORMs? In other words, what kind of variations in fracking-associated NORM are you seeing in different plays?

• We have only investigated the NORM/chemistry in the Marcellus Shale. It will be interesting to see whether the lessons we have learned from the Marcellus Shale generally apply to the partitioning of NORM in other formations. Note that different formations are hydraulically fractured with different blends of fluids that may alter the fate of NORM within the formation and alter which NORM emerge from depth.


• Would land application of flowback water or drill cuttings be environmentally safe at some levels of NORM?

• Limiting exposure to radioactive materials is a good idea. Note that different individuals will have different tolerances for radioactive exposures. The potential health risks of application of NORM on land will not only depend on the levels of NORM, environmental conditions, but also the characteristics of the population exposed. Determining whether NORM disposal on land is safe, extends beyond the science, and includes social, political, and population distribution considerations.

Question and Answer #14 • I’m interested to know the loading conditions of the

sample prior to the TRU/TEVA separation. Also, what are the valence states of Po and U from the load solution? If you can provide any specifics of the TRU/TEVA separation scheme I would appreciate it. I’m curious because I have not seen a TRU/TEVA tandem arrangement.

• This is the topic of a forthcoming publication. We will share this information as soon as it is published.

Question and Answer #15 • I understand that Radium is soluble in low-sulfate brines, so it makes sense that

(in the Marcellus Shale formation) flowback water will have a higher concentration of Ra-226 compared to bit cuttings, and the total activity in the flowback water will increase over time as the Ra-226 decay products grow in. My question is, why doesn’t the same increase in activity levels occur with bit cuttings? My understanding is that the bit cuttings are considered to be in secular equilibrium, and typically don’t contain nearly as much Ra-226 as the flowback, but since the bit cuttings contain the parent isotopes of Ra-226, wouldn’t the bit cuttings still exhibit some sort of increase in activity over time as Ra-226 and the subsequent decay products are produced?

• The increase in flowback is observed because decay products are not soluble. Thus there is a partitioning process that is followed by natural ingrowth over time. We have not yet completed analyses of bit cuttings. With bit cuttings we expect there will be radium adsorbed to the surface of the minerals as well as contained in the rocks. Presumably some of the radium will be contained with in the rocks. As radium in the rocks decays, its decay product radon would likely be trapped and unable to partition away from the original source of radium. Thus there would be no increase in radioactivity, because the maximum radioactivity would already be established due to the lack of partitioning within the rocks. We are certainly interested in investigating the behavior of adsorbed radionuclides on bit cuttings.

Upcoming NAMP Radiochemistry

Webinars

• Introduction to the Fuel Cycle – June 26, 2014

• Front End: Uranium Mining, Milling, Enrichment and UO2 Production – July 24, 2014

• Environmental and human contamination in the Front End of the Fuel Cycle for Uranium Mining and Milling – August 21, 2014

Visit the NAMP website at www.wipp.energy.gov/namp