### MEMORANDUM

TO: Lisa Biddle , EPA

Karen Milam, EPA

FROM: Sarah Yates

, ERG

DATE: June 6

, 201 6

SUBJECT: Radio act ive Material s in the Unconventional Oil and Gas (UOG) Industry

( DCN SGE 01185 )

T his memorandum describes UOG extraction wastewater concentrations for certain radioactive materials fo r the Technical Development Document for Effluent Limitations Guidelines and Standards for Oil and Gas Extraction (TDD) ( DCN SGE0 1188). Radioactive materials, such as radium, radon, and uranium, have been detected in wastewater generated by the UOG extraction industry (DCN SGE00241, DCN SGE 01188 ). Specifically, this memorandum provides background information about radioactive materials in UOG extraction wastewater, including general background about radioactivity and how it is measured, issues related to the analysis of radioactive materials in UOG extraction wastewater, ongoing studies

, and potential concerns about radioactive materials in UOG extraction wastewater. The Crosswalk Memorandum between Proposed and Final Technical Development Document for Effluent Limitations Guidelines and Standards for Oil and Gas Extraction: Tables and Figures (DCN SGE01334) contains a crosswalk of all ta bles and figures in the TDD. Appendix F of the TDD contains the name of the relevant supporting memorandum for each TDD table and figure

, where applicable. This memorandum is organized into the following sections:

 Section 1.0 Background: radioactivity and how it is measured

 Section 2.0 Measurement of radioactivity in UOG ext raction industry wastewater

 Section 3.0 Studies of radioactive material in UOG extraction industry wastewater

 Section 4.0 radioactive materials in UOG extraction wastewater and associated

concerns

 Section 5.0 describes ERG’s quality a ssurance procedures.

 Section 6.0 lists the references used for these analyses.

For definitions of common terms used throughout the TDD, the supporting memoranda,

an d memoranda attachments, please refer to the Glossary in the introduction of the TDD.

1.0 B ACKGROUND : R ADIOACTIVITY AND H OW IT IS M EASURED
Radioactivity and Ionizing R adiation. Radioactivity is the property of some unstable atoms that causes them to spontaneously decay and give off energy (radiation) as particles or
rays. This phenomenon is known as radioactive decay. Because the r adiation emitted duringMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 2

radioactive decay has enough energy to break chemical bonds, it is refer red to as ionizing radiation. The three main kinds of ionizing radiation are ( DCN SGE00 936 ) : 1

 A lpha p articles , which include two protons and two neutrons (essentially a helium nucleus);

 B eta p articles , which are essentially high

- speed electrons; and

 G amma r

ays and x

- rays , which are pure energy (photons).

The descriptions of these types of ionizing radiation provided below are taken from Keenan 1971 (DCN SGE00 179 ) and EPA’s radiation protection website (DCN SGE00936)

. Alpha particles emitted from a given nuclide 2 have energies confined to a few discrete values, so that the energies of alpha particles can identify the nuclide from which they are emitted. Some nuclides emit alpha particles at more than one speed. For example 226 Ra (radium

226) emits alpha pa rticles at either 1.517e9 or 1.488e9 centimeter/second ( cm/sec ) . The emission of the slower particle is followed by the emission of a gamma ray, such that equal energy is emitted in each case. The loss of an alpha particle reduces the mass of the nucleus a nd also changes the atom to a different element (the number of protons determines the element). For example, when radium

- 226 ( 226 Ra) emits an alpha particle, it loses two protons and two neutrons

. The atomic mass is reduced from 226 to 222 and the 226 Ra at om becomes an atom of 222 Rn ( radon

- 222 ) , a radioactive gas.

Beta particle e mission occurs when the ratio of neutrons to protons in the nucleus is too high. In this case, an excess neutron transforms into a proton

, which stays in the nucleus

, and a beta particle (high speed electron) is ejected energetically. Unlike alpha particles, beta particles are emitted at all possible speeds (term of art: beta spectrum) . When the ejection of the beta particle does not rid the nucleus of sufficient energy, the nucle us releases the remaining excess energy in the form of gamma radiation. Like alpha particle emission, emission of a beta particle also changes the atom to a different element . For example, 228 Ra (radium

- 228) is a beta emitter. During its radioactive decay, a neutron in the nucleus conver ts to a proton and the nucleus emits a beta particle. The number of protons increases from 88 to 89, changing the atom from radium
to actinium ( DCN SGE00936 ) . Even though the atom is a different element

, because neutrons and protons have the same mass, the atom retains the same atomic mass number : beta decay
converts 228 Ra to 228 Ac ( actinium

- 228 )

.
Gamma radiation emission occurs when the nucleus of a radioactive atom has too much energy. It often follows the emission of a beta particle and can also follow the emission of an alpha particle (there are no pure gamma emitters) . In either case, the energies of the gamm a radiation from a given nuclide are limited to a few discrete values, that is, discrete wavelengths

, and can be used to identify the nuclide

.

1 Other kinds of ionizing radiation exist but are not germane to this discussion (e.g., neutrons).

2 Nuclide is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons

, its number of neutrons , and its energy state. An element is a substance in which all atoms have the same number of protons; atoms of the same element with different numbers of neutrons have differing atomic w eights and are called isotopes ( DCN SGE00 179). 226 Ra and 22 8 Ra are isotopes of radium with atomic weights of 226 and 228, respectively.Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 3

Measuring R adioactivity

. Radioactivity is measured using electronic detectors coupled to instrumentation used to count the number of atomic disintegrations per unit of time

. Whether a radioactive material emits alpha particles, beta particles, or gamma rays, the quantity of radioactive material is expressed in terms of its radioactivity (or simply its activity), in units of measure of the curie (Ci) or becquerel (Bq) ( DCN SGE00977 )

.

A curie (Ci) i s a non

- SI unit for radioactivity

, defined as 37 billion disintegrations per second 3 . Thus, a radioactive sample that has an activity of 74 billion disintegrations per secon d has an activity of 2 curies. The curie is a very large unit for quantities found in the environment. Scientists use the following fractions of a curie as well :

 Picocuries (pCi) are 1 trillionth of a curie (1 x 10

- 12 Ci). Picocuries are used in measuring the typically small amount of radioactivity in air and water.

 Other fractions such as millicuries (mCi), or 1/1000 Ci and nanocuries (nCi), or 1 billionth of a curie, are used as needed ( DCN SGE00936 )

.

A Becquerel (Bq) is the SI unit for radioactivity and is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. Therefore, the Becquerel is the same as an inverse second (s

- 1 ). The conversion between Becquerel and curie is 1 Ci = 3.7 × 10 10 Bq.

Measuring Radiation . The units for exposure in air are the roentgen ( R ) and coulomb/kilogram (C/kg). There are also similar units for measuring absorbed dose in tissue (rad and Gray) and dose equivalent for the absorbed dose and biological effects (rem and Sievert)

. Instrumentation for Detecting Radioactivity. The energy of radioactive decay can be detected by a variety of instruments that quantify the amount of radioactivity present in a sample (the disintegrations per second). Some techniq ues can also measure the detected energy and identify the radioactive isotope that is emitting the radiation. The following descriptions of

common radioactivity measurement techniques are take n from U.S. EPA, 2011 ( DCN SGE00937 )

. Liquid Scintillation Cou nting

– a radioactive sample is mixed with solvent and chemicals that emit light pulses when they are excited by radiation. This technique is t ypically used to measure the radioactivity of beta emitting radionuclides, such as 3 H (tritium). With analysis of the energy of the emitted radiation and the duration of pulses, liquid scintillation counters can identify the alpha and beta emitting isotopes present in a sample.

Gas Fl ow Proportional Cou nting

– a radioactive sample causes a gas inside a detector tube to ionize and release electrons. The released electrons move to the anode and the signal is recorded. Gas proportional counters are sensitive detectors for alpha and beta particle emissions and are u sed for EPA Method 900.0 (gross alpha and gross beta radi oactivity screening)

.

3 The curie was originally a comparison of the activity of a sample of radioactive material to the activity of one gram of radium, which at the time was measured as 37 billion disintegrations per second. When more accurate techniques measured a slightly different activity for radium, the reference to radium was dropped ( DCN SGE00936 ).Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 4

Alpha Spectr ometry

– alpha particles emitted from a radioactive sample collide with atoms in a germanium or silicon crystal detector, releasing electrons that are amplified and detected as an electric pulse. Because nuclides emit alph a particles at discrete energies, alpha spectrometry can sometimes identify the radionuclide in a purified sample, in add ition to counting its activity.

Gamma Spectr ometry

– crystal detectors interact with gamma rays from a radioactive sample by absorbing energy and re

- emitting it as light. Crystals used for gamma ray detectors include thallium

- doped sodium iodide and high

- purity germanium (HPGe). HPGe crystals must be cooled to liquid nitrogen temperature 4 for use in gamma spectrometry. HPGe detectors can distinguish energy of gamma ray sources and identify the radionuclides in a sample. Activity of radionuclides that emit only alpha particles and beta particles with no accompanying gamma radiation will not be detected by gamma spectrometry.

Naturally Occur ring Radioactive Materials . Certain radionuclides occur naturally in minerals and rocks in the earth’s crus t

. As radioactive elements decay, the parent elements form

new elements (progeny or daughter products )

. I f the progeny are also radioactive

, they will continue to decay in a chain that continues until a stable (non

- radioactive) end product is reached. Uranium and thorium are naturally occurring radioactive elements found in trace amounts in most rocks and soils ( DCN SGE00782, DCN SGE00783 ) , includi ng formations from which UOG resources are extracted

. Urani u m and thorium decay chains include radium, radon, and other radionuclides, and ultimately re ach a stable non

- radioactive lead isotope that does not decay further ( DCN SGE00795 ). Uranium and thorium decay chains are depicted in Figure 1

- 1

. Other naturally

- occurring elements that are non

- series radionuclides include 40 K ( potassium

- 40) and 87 Ru ( rubidium

- 87)

. 40 K is often present in mineral samples. Rubidium is also ubiquitous and used in dating mineral samples.

4 Liquid nitrogen held at atmospheric p ressure maintains a temperature of −321 o F /

− 196 o C, its boiling point.Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 5

Figure 1

- 1 . Decay Chains for ( A. ) 238 U and ( B. ) 232 ThMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 6

Naturally occurring radioactive material (NO RM) is a term often used to refer collectively to material that contains radionuclides at concentrations found in nature. Radionuclides found in NORM associated with UOG extraction include uranium, thorium, and their respective decay products (DCN SGE00 795 ). The term technologically enhanced naturally occurring radioactive materials (TENORM) is now used to distinguish clearly between radionuclides as they occur naturally (NORM) and NORM radionuclides that human activity has concentrated or exposed to the en vironment (TENORM) ( DCN SGE00973 , DCN SGE01126 )

. Examples of human activity that exposes and/or concentrates NORM are oil and gas extraction, mining, and w ater and wastewater processing.

The radioactive elements uranium and thorium commonly occur in the sa me sedimentary sandstones and shale formations as UOG resources (DCN SGE00241). For example, Rowan et al., 2011 (DCN SGE00241) studied radi um content in a UOG formation ( the M arcellus Shale, an organically

- rich black shale). They explain that organic carbo n, the source of oil and gas, is known to play a role in concentrating uranium. As shown in the de cay chains depicted in Figure 1

- 1, 238 U ( uranium

- 238 ) decays to 226 Ra , while 232 Th decays to 228 Ra . Water found in the pores of UOG formation rocks (i.e., formation water) is typically highly saline and found in oxygen

- poor, reducing environments. Uranium and thorium are poorly soluble under these conditions, but radium solubility is enhanced (DCN SGE0 0241). For this reason, formation water is relatively enriched in radium isotopes compared to their parent nuclides, 238 U and 232 Th (DCN SGE00975)

.
2.0 M EASUREMENT OF R ADIOACTIVITY I N UOG E XTRACTION W ASTEWATER
Chapter C.3 of the TDD (DCN SGE 01188 ) presents the concentrations of 226 Ra, 228 Ra, and the parameters gross alpha and gross beta in UOG extraction wastewater

. This section discusses the methods used for measuring radioactivity in UOG e xtraction wastewater reported in the TDD.

2.1 EPA Approved Test Procedures for Radioactive Materials in Wastewater

EPA identifies approved test procedures (methods) for the analysis of pollutants in
wastewater in 40 CFR Part 136. EPA requires the use of t hese test procedures whenever the

wa ste constituent is required to b e measur ed for NPDES permit applications and NPDES permit compliance reports. As shown in Table 2

- 1 , fo r radioactive materials, 40 CFR Part 136 includes test procedures for:

 G ross alpha and gross beta radioactivity (Method 900.0) ;

 A lpha emitting radioisotopes of 223 Ra

, 224 Ra and 226 Ra (Method 903.0) ; and

 226 Ra , radon emanation technique (Method 903.1).Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 7

Table 2

- 1

. List of Approved Radiologic Test Procedures

Parameter and U nits Method EPA Reference 1 Alpha

- Total, pCi per liter Proportional or Scintillation Count er 900.0
Beta

- Total, pCi per liter Proportional Counter 900.0 Radium Total, alpha emitting isotopes, pCi per liter Proportional Counter 903.0

226 Ra , pCi per liter Scintillation Counter 903.1 Source: 40 CFR Part 136. Table IE

. 1 Prescribed Procedures for Measurement of Radioactivity in Drinking Water, EPA

- 600/4

- 80

- 032 (1980), U.S. Environmental Protection Agency, August 1980. Appendix B provides method for measuring alpha and beta counting error.

EPA does not have an approved method for measuring uranium and thorium in
wastewater . EPA approved methods are de scribed in this section

. 900.0 Gross Alpha and Gross Beta Radioactivity Summary: This method covers the measurement of gross alpha and gross beta particle activities. The method is a screening technique for alpha and beta particle activities

. An aliquot of a preserved sample is ev aporated to a small volume and transferred quantitatively to a tared 2

- inch stainless steel counting planchet. The sample residue is dried to constant weight, reweighed to determine dry residue weight, and then counted for alpha and/or beta radioactivity u sing a gas

- flow proportional counting system or scintillation detector system . Counting efficiencies for both alpha and beta particle activities are selected according to the amount of sample solids from counting efficiency vs. sample solids standard curve s.
Interfere nce Issues: Alpha and beta particles have lower energy than gamma radiation with limited ability to pass through solids. Because Method 900.0 requires drying a standard volume water sample, a sample with high salt concentration typical of some UOG wastewater will produce a thick solids residue

. To ensure the alpha and beta particles in the sample can be counted, the solids thickness must be limited by reducing the sample volume. This reduces the method sensitivity, making it difficult to measure low levels of radioactivity in a sample of highly saline UOG wastewater

.

As further explained in DCN SGE00974 : “The amount of [suspended and dissolved] solids in a sample limits the size of sample that can be processed and thereby the sensitivity of the measurement. Method 900.0 restricts residue thickness for gross alpha measurements to a maximum of 5 mg/cm 2 . In a 50

- mm diameter stainless

- steel planchet, this is equivalent to 100 milligrams of solid residue. While this method is applicable to samples which generally hav e solids content under 500 mg/L ... [ UOG wastewater ] samples may have solids content in the hundreds of thousands of mg/L and sample sizes would be restricted to a small fraction of a milliliter in order not to exceed the maximum residue t hickness

. For this reason, the capability of the method to detect activity could be decreased by a factor of one

- thousand and the ability of the evaporation approach to detect radioactivity in

... [ UOG wastewater ] becomes questionable at best.”

903 .0 Alpha

- E mitting Radium Isotopes Summary: This method covers alpha emitting radioisotopes of radium : 22 3 Ra

, 22 4 Ra

, and 226 Ra

. R adium in a water sample is collected by co

-Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 8

precipitation with barium and lead sulfate, and purified by re

- precipitation from ethylenediaminetetracetic acid ( EDTA ) solution. Citric acid is added to the sample to assure that complete interchange occurs before the first precipitation step. The final barium sulfate ( BaSO 4 ) precipitate, which includes 226 Ra

, 22 4 Ra , and 22 3 Ra is alpha counted to determine the total disintegration rate of the radium isotopes.

Interference Issues: Because Method 903.0 requires a co

- precipitation of radium with barium sulfate, high test sample concentrations of Group II elements (magnesium, calcium,
stron tium, barium) will interfere with the radium recovery and result in inaccurate
measurements. As shown in TDD Table s C

- 16 and C

- 17

, Group II element concentrations in UOG extraction wastewater can reach hundreds of thousands of mg/L, so that the accuracy of Method 903.0 for UOG wastewater may be reduced.

903.1 226 Ra , Radon Emanation T echnique

. Summary: This method is specific for 226 Ra

, and is based on the emanation and scintillation counting of 22 2 Rn , a daughter product of 226 Ra

. 226 Ra in the water sample is concentrated and separated by coprecipitation on barium sulfate. The precipitate is dissolved in EDTA reagent, placed in a sealed bubbler and stored for ingrowth of
22 2 Rn . After ingrowth, the gas is purged into a scintillation cell. When the short

- lived 22 2 Rn daughters are in equilibrium with the parent ( after about four hours ), the scintillation cell is counted for alpha activity.

All of t he alpha

- emitting radium isotopes 226 Ra

, 22 4 Ra , and 22 3 Ra undergo decay to radon isotopes. However, only the progeny of 226 Ra

, 22 2 Rn

, has a half

- life long enough to be useful for analytical measurements. The other radon isotopes have half

- lives of less than one minute. Thus when the 22 2 Rn is separated from all the other radium isotopes, the other radon progeny decay qui ckly enough so that they do not interfere with the measurement of 22 2 Rn and its progeny.

Interference Issues: The method reports that t here are no radioactive interferences in this method

. Because t he method requires a co

- precipitation of radium with barium sulfate, high test sample concentrations of Group II elements (magnesium, calcium, strontium, barium) may interfere with the radium recovery and result in inaccurate measurements. As shown in TDD Table C

- 16 and C

- 17, Group II element concentrations in UOG extraction wastewater can reach hundreds of thousands of mg/L , so that the accuracy of Method 903. 1 for UOG wastewater may be reduced.

2.2 EPA Approved Test Procedures for Radioactive Materials in Drinking Wate r
Only the methods listed in Table 2

- 1 are approved for use in the NPDES permit program

. EPA has additional approved test procedures for radiological parameters in dr inking water that researchers have applied to UOG wastewater. These methods includ e test procedures for:

 22 8 Ra in drinking water (method 904.0);

 Gamma emitting radionuclides in drinking water (method 901.1).

904 .0 228 Ra Summary: This method covers the measurement of 22 8 Ra in drinking water

. Although it is not approved for use in the NPDES program, researchers have used it to measure
22 8 Ra in UOG wastewater. R adium in the water sample is collected by co

- precipitation with barium a nd lead sulfate and purified by re

- precipitation from EDTA solution. Both 226 Ra andMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 9

22 8 Ra are collected in this manner. After a 36 h ou r ingrowth of 22 8 Ac from 22 8 Ra , the 22 8 Ac is carried on yttrium oxalate, purified

, and beta counted. If 226 Ra is also desired, the activity in the supernatant can be reserved for co

- precipitation on barium sulfate, dissolv ed in EDTA and stor ed for ing rowth in a sealed radon bubbler (see Method 903.1).

Interference I

ssues: Because the Method 904.0 require s a co

- precipitati on of radium with barium sulfate, high test sample concentrations of Group II elements (magnesium, calcium, strontium, barium) will interfere with the radium recovery and result in inaccurate

m easurements. As shown in TDD Table C

- 16 and C

- 17, Group II element concentrations in UOG extraction wastewater can reach hundreds of thousands of mg/L , so that the accuracy of Method 904.0 for UOG wastewater may be reduced.

901.1 Gamma Emitting Radionuclides in Drinking Water Summary: This method covers the use of gamma spectroscopy for the measurement of gamma photons emitted from radionuclides without separating them from the sample matrix. This technique is used to measure concentrations of specific gamma emitters in a drinking water sample. Although it is not

a pproved for use in the NPDES program, researchers have used it with modern gamma spectrometers to measure 226 Ra and 22 8 Ra in UOG wastewater. The method requires :

 The container configuration for the standards and the samples to be identical (i.e., geometry of the sample wit h respect to the detector), and

 The sample to be properly acidified and not contain any sediment.

Interference Issues: Interferences result from the presence of more than one gamma emitting radionuclide in the sample. Resolution of modern (HPGe) detectors is very good; however, they cannot resolve gamma

- ray energies that are within ~ 0.5 kiloelectron volt ( keV ) of each other. Evaluation of the spectra by a trained spectroscopist is necessary to ensure proper reporting.

2.3 Development of Methods for Determination of Gross Alpha and Gross Beta and Radium Levels Specific to UOG Extraction Wastewater

B ecause of the generally high ionic strength ( i.e., salt concentration) of UOG extraction wastewater, the accuracy of methods such as EPA M ethod s 900.0, 903.0

, and 904.0 is questionable for analysis of UOG extraction wastewater. To address the se difficulties , EPA and other researchers are developing methods tailored to UOG extraction w astewater

. This section summarizes published results of th e development of two methods specific to UOG extraction
wastewater.

Gross Alpha and Gross Beta Activity. In response to the difficulty of applying approved methods to UOG extraction wastewater samples, EPA’s National Analytical Radiation Environmental Lab oratory and National Exposure Researc h Center cooperated in the development of the Rapid Radiochemical Method for Gross Alpha and Gross Beta Activity in Flowback and Produced Water from Hydraulic Fracturing Operations (FPWHFO) ( DCN SGE00974 ) . As reported i n this document , the optimized method consists of measuring activity of alpha emitters by two methods (liquid scintillation counting and gamma spectrometry) . The results of these measurement methods, described further below, may be summed to representMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 10

tota l gross alpha. Beta emission activity of 22 8 Ra is measured separately by gamma s pectrometry
, as described below (DCN SGE00974)

. Thorium (Th), uranium (U), and polonium ( Po ) Gross Alpha by L iquid S cintillation C ounting

. A 300 mL sample is trea ted with permanganate in ammonia cal solution to coprecipitate all radionuclides in the naturally occurring series. The mixture is settled and the supernatant solution discarded. The residue is dissolved in hydrochloric acid and passed through a TRU ResinTM column (Eichrom Technologies, LLC, Lisle, IL).Thorium, uranium

, and polonium are eluted from the resins using ammonium oxalate. The eluent is transferred to a liquid scintillation vial as the final sample test source and counted in the alpha emission regio n of the liquid scintillation spectrum. The final sample test so urce is counted for 30 minutes.

226 Ra Alpha by Gamma Spectrometry. A sample test source of 3 L is counted directly by gamma ray spectrometry. The activity concentration of 226 Ra is determined by gamma ray analysis using a specified energy gamma ray region ( the 186 keV photopeak ) and assumes no significant amount of 235 U ( uranium

- 235 ) c ompared to the amount of 226 Ra in the sample 5 . The sample is counted for 12 hours or long enough to achieve the re quired method uncertainty.

228 Ra Beta by Gamma Spectrometry

. The sample test source of 3 L is counted directly by gamma ray spectrometry. In addition to 22 8 Ra being determined indirectly by analysis of its first
progeny , 22 8 Ac

, several other radionucli des are determined directly by their gamma ray emission and others may be determined indirectly through analysis of a parent or progeny radionuclide that is a gamma ray emitter. The sample is counted for 12 hours or long enough to achieve t he required meth od uncertainty.

The method developers noted that additional work was needed to optimize and validate portions of the method . Also, because the activity of samples containing natural decay chain activity, especially 226 Ra and 22 4 Ra , changes over time due to radioactive ingrowth and decay processes, questions about timing of wastewater generation, sample collection, preparation and counting must be addressed ( DCN SGE00974 )

.

226 Ra and 228 Ra

. R esearchers from the University of Iowa examined alternative methods for determining radium levels in UOG extraction wastewater

. Working with a sample of Marcellus shale wastewater from northeastern Pennsylvania, Nelson et al

. , 2014 (DCN SGE00975)

, found that barium sulfate coprecipitation, the basis for EPA method 903.0, r esulted in very poor recovery of radium (<1% of spiked activity of 226 Ra )

. The researchers explored four alternative methods and determined that HPGe gamma spectroscopy was the most promising method for determining levels of 226 Ra in UOG extraction wastewater, using a 3 L sample (stabilized with agar) counted for 17 hours. Researchers are continuing to evaluate the use of an electronic radon detector (Durridge RAD7) to quantify radium by measuring radon decay products. Although counting times wit h th e radon detector method are shorter than HPGe gamma spectroscopy , sufficient hold time for radon ingrowth, 4 to 30 days, is required. R esearchers are continu ing development of this method.

5 Gamma

- ray spectrometry may also be used to determine t he activity of the 226 Ra beta

- gamma emitting progeny

, 214 Pb (lead

- 214) and 214 Bi (bismuth

- 214); however, these emissions are no t included in the quantitation of 226 Ra by the method described in DCN SGE00974

.Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 11

3.0 S TUDIES OF R ADI OA CTIVE M ATERIAL IN UOG E XTRACTION W ASTEWATER

The fo llowing subsections describe studies related to radioactivity in the UOG industry

. This is not a comprehensive review but includes studies that EPA identified during the development of the pretreatment standards for UOG extraction wastewater

.
3.1 P ennsylvania Department of Environmental Protection (PA DEP ) TE NORM Study ( DCN SGE 01028 )

In January 201 5

, PA DEP announced the results of a study of radioactive elements in UOG extraction wastewater, sludge, and drill cuttings. Liquid and solid s amples were analyzed for alpha, beta, and gamma radiation and gas samples were analyzed for radon using the following methods ( DCN SGE0 1028 ) :

 EPA Method 901.1: Gamma spectroscopy to identify TENORM radionuclides;

 DOE Health and Safety Laboratory (HASL) 300: Alpha spectroscop y to identify isotopic uranium and isotopic thorium; and

 EPA Method 900 .0: Gross alpha and gross beta.

In samples of flowback fluid and produced water, 226 Ra concentrations were elevated, ranging up to 26,600 pCi/L. 22 8 Ra was also detected in these samples, at up to 1,900 pCi/L. Although PA D E P concluded

, “ ...[ t] here is little potential for radiological exposure to workers and members of the public from handling and temporary storage of [flowback fluid and] produced water on natural gas well sites ,” they did conclude “...[t]here is a potential for radiological environmental impacts from spills of produced water [and flowback fluid] on natural gas well sites and from spills that could occur from the transportation and delivery o f ...[these] fluid[s]. ”

At ten POTWs, PADEP sampled treated and untreated wastewater and wastewater treatment sludge (filter cake). Six of the 10 POTWs are considered influenced (POTW

- I) by having received wastewater from the oil and gas ( O&G ) industry, mainly the effluent of CWTs. Four of the sampled POTWs never received wastewater from the O&G industry. Because the measured concentrations shown in Table 3

- 1 are higher than concentrations found in surface water (see TDD Table C

- 20) and soil ( D CN SGE01028 Table 2

- 2), there may be some potential for radiological contamination by discharges from POTWs treating UOG extraction wastewater.

Table 3

- 1. Radium Concentrations, Influent vs

. Effluent for Six POTWs receiving Oil and Gas W astewater Sample Description 226 Ra (pCi/L) 228 Ra (pCi/L) Influent, Unfiltered (Average) 190 28.1 Effluent, Unfiltered (Average) 103 10.4 Source: DCN SGE01028 Table 4

- 18
Samples of filter cake from the six POTWs receiving O& G wastewater showed “Ra

- 226 and Ra

- 228 present above typical background concentrations in soil. The average Ra

- 226 result was 20.1 pCi/g with a large variance in the distribution, and the maximum result was 55.6 pCi/g.Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 12

The average Ra

- 228 result was 8.32 pC i/g, and the maximum result was 32.0 pCi/g Ra

- 228.” (DCN SGE01028)

PADEP concluded, “...[t]here is little potential for radiological exposure to workers and members of the public from handling and temporary storage of filter cake at POTW

- I’s. However, there is a potential for radiological environmental impacts from spills and the long

term disposal of POTW

- I filter cake ” . (DCN SGE01028)

3.2 A rgonne National Laborator ies (A NL ) Bakken NORM S tudy

The North Dakota Department of Health contracted Argonne National Labo ratories to conduct a risk assessment of radioactive waste generated from UOG drilling in North Dakota’s Bakken formation. North Dakota does not allow disposal

, within the state, of radioactive waste containing greater than or equal to 5 pCi/L. However, No rth Dakota has experienced problems with trucking companies illegally dumping radioactive waste , including waste generated from the management of UOG extraction wastewater ( DCN SGE00968, DCN SGE00970)

. The study focused on the concentrations of radioactive elements in UOG industry solid
waste generated during the management of UOG wastewater (e.g., scale, sludge, filter cakes, filter socks) and provided background information on TENORM waste streams. It also evaluated the radiological doses associated with a number of scenarios associated with oil and gas well site operations, improperly managed wastes, transportation of TENORM, and disposal of TENORM in Industrial Waste and Special Waste Landfills

. S tudy results were released in November 2014 ( DCN SGE0 1018 )

. The study supported revisions to North Dakota’s rules for radioactive waste disposal (DCN SGE01 333 )

.

4.0 R ADIOACTIVE M ATERIALS IN UOG E XTRACTION W ASTEWATER AND A SSOCIATED

C ONCERNS
Oil and gas formations contain varying levels of NORM resulting from uranium decay, which may be transferred to UOG extraction wastewater. This section presents the concentrations of radioactive constituents compiled for the TDD, discusses, in general term s, the harm caused by ionizing radiation (whether from UOG extraction wastewater or other sources)

, and discusses the particular concerns associated with TENORM in UOG extraction wastewater.

4.1 Radioactive Materials Measured in UOG Extraction Wastewater

The EPA identified only limited radioactive constituent concentration data for UOG extraction wastewater. As presented in Table 4

- 1 6 , most available da ta characterize produced water from the Marcellus formation; limited data were available from the Niobrara formation.
226 Ra and 22 8 Ra are both found in UOG produced water in both of these UOG formations , with
226 Ra concentrations generally two to five time s greater than 22 8 Ra concentrations. The EPA also identified li mited data about radioactivity in drilling wastewater 7 ; Table C

- 18 in the TDD (DCN

6 The generation of the data in Table 4

- 1 is explained in the Unconventional Oil and Gas (UOG) Produced Water Volumes and Characterization Data Compilation memorandum ( DCN SGE 01184). This memorandum includes a description of the unde rlying data sources, data analysis, and QC procedures.

7 Information about radioactive constituent concentrations in UOG drilling wastewater can be found in the Unconventional Oil and Gas (UOG) Drilling Wastewater memorandum (DCN SGE01181).Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 13

SGE 01188 ) presents a summary of 5 data points for gross alpha and gross beta concentrations in UOG drilling wa stewater from the Marcellus shale formation

.

Table 4

- 1 . Concentrations of Radioactive Constituents in UOG Produced Water

Parameter Formation Method(s) Range a (pCi/L) Median

(pCi/L) Number

of Data Points Number

of Detects Gross alpha Marcellus 900.0 4.7

- 24,000 8,700 103 101 Gross alpha Niobrara 900.0 300

- 820 1,800 3 3
Gross beta Marcellus 900.0 0.66

- 1,700 1,600 94 92
Gross beta Niobrara 900.0 170

- 420 760 3 3

226 Ra Marcellus 901.1 Mod., 903.0, 903.1, γ

spectrometry 10

- 88,000 1,700 74 74

226 Ra Niobrara 901.1 Mod. 960

- 3,300 620 3 3

228 Ra Marcellus 901.1. 903.0, 904.0, γ

spectrometry 15

- 16,000 470 73 72

228 Ra Niobrara 901.1 Mod. 400

- 1,100 330 3 3

a

– Range values represent the 10 th and 90 th percentile values of the data Source: DCN SGE 01184

4.2 General Information about Harm Caused by Ionizing Radiation

Ionizing radiation is known to harm living tissue in humans and other organisms. The extent of harm depends on route s and duration of exposure and the energy and types of ionizing radiation (alpha and beta particles and gamma rays). Radiation exposure can occur externally, when the radiation source is outside of the organism. External exposure is of particular concern f or radionuclides that emit gamma rays which have sufficient energy to penetrate containers, clothing, and skin. Internal exposure is a greater concern for radionuclides (such as radium) that emit alpha and beta particles. Although alpha and beta particles do not penetrate far into tissue, inside the body they will deposit their energy in a small volume of tissue, causing greater damage ( DCN SGE01 020). Internal exposure results mainly from ingestion (e.g., drinking water, food) and inhalation (e.g., inhaling a radioactive gas such as radon or contaminated dust).

All of the radionuclides present in UOG wastewater generate ionizing radiation that is potentially harmful to human health and the environment; however, a s discussed previously, because of their greater solubility in UOG formation water 8

, radium isotopes (particularly 226 Ra and 22 8 Ra ) are present in UOG wastewater at higher concentrations than other radionuclides (DCN SGE00975) . Further, radium is of particular concern because its chemical behavi or is similar to calcium, magnesium and other Group II elements. Whereas external radiation is instantaneous (i.e., does not remain in the body after the exposure)

, internal deposition of radionuclides can present a hazard for long periods of time after the initial exposure. Because it behaves similarly to calcium, ingested radium may be stored in the body and can replace calcium in tissues, particularly bone. Long

- t erm internal exposure to radium increases the risk of developing bone and other cancers. Because radium readily accumulates in the body, it is

8 Formation wa ter is water that occurs naturally within the pores of rock.Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 14

considered to pose a greater cancer risk than m ost other radioactive elements (DCN SGE00980 ). Additionally, near

- surface radium deposits may be a source of indoor radon in the future if homes are built over radium

- contaminated soils.

In addition to potential harm to human health, radium that accumulates in river and stream sediments could harm benthic organisms. Warn er, et al write, “Bioaccumulation of radium is known to occur in freshwater fish [and] invertebrates...Radium also accumulates in freshwater plants...” (DCN SGE00629).

4.3 Potential Concerns Associated with TENORM in UOG Extraction Wastewater

Transfer of TENORM t o the environment may result from management of UOG extraction wastewater. UOG operators use three primary practices to manage UOG extraction wastewater (DCN SGE 01188 ):

 Dispose of wastewater via underground injection for disposal wells (“disposal wells”);

 Reuse /recycle wastewater in subsequent fracturing jobs; and

 Transfer wastewater to a centralized waste treatment (CWT) facility.

While implementing these practices, radioactive materials may be removed from the wastewater stream in sludges that accumula te in tanks and equipment, during filtration of suspended solids from wastewater, or by chemically changing radium from a soluble to insoluble form during wastewater treatment. The following bullets summarize the potential concerns identified in the litera ture associated with TENORM during the management of UOG extraction
wastewater.

 Build

- up of Radioactive Elements in Scale

– During transport of UOG extraction wastewater, radium may precipitate with other scale

- contributing constituents (e.g., calcium, str ontium) resulting in a TENORM

- containing scale in pipes and valves (DCN SGE00622). Conventional oil and gas (COG) wastewaters, which have constituents similar to UOG wastewater, have been documented to generate radioactive scale. As discussed in DCN SGE001 36, in studies of the COG industry, the American Petroleum Institute found the highest concentrations of radioactivity in wellhead piping scale. Radium concentrations measured in the scale on pipes and valves used to manage COG extraction wastewater averag ed 480 pCi/g, ranging up to 400,000 pCi/g, depending on regional geology (DCN SGE00 136 ). 226 Ra and 22 4 Ra

, contained in the scale

, decay into radon gas and present an inhalation hazard when workers contact the scale. Buildup of 210 Pb (lead

- 210) and 210 Po ( polonium

- 210) in thin films and scales on the interior of equipment on natural gas wells and equipment are also a concern. P eople working with scale

- encrusted equipment, pipes, and valves may be exposed to radiation, either externally or internally via inh alation or inge stion of radioactive materials.

 Sludge and Filter Residues

– As reported in DCN SGE01018 , “T ENORM

contaminated sludges can accumulate in the bottom of vessels that are used toMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 15

store or otherwise manage

... [UOG extraction wastewater] , includin g water

storage tanks, oil/water separators, and heater treaters. Sludges typically are composed of solid debris, such as sand, scale, or rust particles, that settle out of the production stream. The primary

... [radionuclides of concern] in sludges in the Un ited States are 226 Ra

, 22 8 Ra , and their decay products

... Typically, the radium takes the form of a co

- precipitate with sulfate or carbonate deposits. In addition, filters that are used to separate particulates from produced water generate a solid waste refe rred to as filter cake. This material is likely to have a similar composition to the sludge that is removed from produced water storage and handling equipment.... Disposable filter socks are used to filter particulates out of produced water prior to transpor t and disposal. These filters accumulate sludges and scales over time and must be changed and disposed of on a regular basis. In the past year, the improper disposal of these filter socks has been a problem in the State of North Dakota ”. (DCN SGE00970)

 Ra dioactivity in Discharges of UOG Extraction Wastewater from Treatment Plants

– The treatment technologies used by wastewater treatment plants may not remove all of the pollutants contributing to radioactivity. As a result, these pollutants will be discharg ed to surface waters. Researcher s measured sediment concentrations at the point of discharge from a brine treatment facility that accepted UOG extraction wastewater. They found 226 Ra at 8,732 Bq/kg (236 pCi/g) and 22 8 Ra at 2,072 Bq/kg, (56 pCi/g) about 200 times greater than upstream and background sediment concentrations. The researchers speculated that the contaminated sediments could pose ecological risks, particularly to benthic organisms (DCN SGE00629)

.

 Site Contamination Potential

– Solid wa stes generated during management of UOG wastewater (e.g., drill ing wastewater filter residues, scale, sludge, treatment residuals) may contain TENORM. These wastes are often disposed of at the drilling site or in landfills. Improper disposal may lead to so il and/or groundwater contamination and/or airborne releases of radon gas (DCN SGE00622)

.

5.0 Q UALITY C ONTROL P ROCEDURES
All of the analyses presented adhered to the Environmental Engineering Support for Clean Water Regulations Programmatic Quality Assurance Project Plan (PQAPP) (DCN SGE00957) and the Unconventional Oil and Gas (UOG) Supplemental Quality Assurance Project Plan (SQAPP) (DCN SGE00 958 ), including collecting, evaluating, and analyzing existing data and information about radioactive materials in t he UOG industry.

Specifically, ERG used the procedures described in Section 4 of the PQAPP to gather and manage existing data in support of the rulemaking. ERG staff entered reference information for relevant sources into the UOG Literature Review database . The ERG index keeper reviewed all reference information, assigned each reference a Document Control Number (DCN ), imported the reference information into the UOG Project File Index database, and saved referenced files in the Electronic Project File folde r.Memorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 16

ERG also used the procedures described in Section 3 of the SQAPP when collecting existing data for use in the UOG rulemaking. ERG used a combination of sources, including reports, papers, and online databases from state regulatory agencies such as depar tments of environmental protection and oil and gas commissions. As shown in Table 6

- 1 , ERG assigned a source flag (A, B, C or D) to all references used in these analyses.

ERG defines each source flag as follows:

 Source Flag A

- J ournal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes);

 Source Flag B

- Documents prepared by a verified 9 source that include citation information (e.g., operator reports, vendor documents, university publications);

 Source Flag C

- Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, conference presentations); and

 Source Flag D

- Documents prepared by a source that could not be verified and that do not include citation information.

ERG collected data and information that were specific to the radioactive elements, analysis procedures, and UOG wastewater of concern

. The references were reviewed for relevance and comparabil ity, and summarized for use in this memo. ERG searched for the best available information, and all but three sources qualify as Source Flag A, as described above. Beginning with federal, state, and local government reports and documents, ERG conducted a th orough literature search, with a particular interest in recent sources and sources that used the EPA Methods of interest (900.0, 901.0, 903.0, 903.1, and 904.0) . Where available, ERG included information from site visits and industry meetings.

6.0 R EFERENCES

Table 6

- 1 lists the sources ERG used along with their DCN and source flag.

Table 6

- 1. References

DCN Source Citation Source Flag a
SGE00136 U.S. EPA. 2011. Oil and Gas Production Wastes.

https://www.epa.gov/radiation/tenorm

- oil

- and

- gas

- production

- wastes A

SGE00179 Keenan, Charles W. and Jesse H. Wood. General College Chemistry. Chapter 14 Nuclear

Changes. Harper & Row Publishers, Inc., New York. 1971. A

SGE00241 Rowan, E.L., et al. 2011. Radium content of oil and gas field prod waters in the N orthern

App Basin. USGS Scientific Investigations Report 2011

– 5135. A

SGE00544 Marcellus Shale Coalition (MSC) and PA Independent Oil and Gas Association

(PIOGA). 2013. Fiel d Sampling Plan. B

SGE00622 U.S. Geological Survey (USGS). 2013. Water Resources and Shale Gas/Oil Production

in the Appalachian Basin. (August). A

9 ERG considered sources as “verified” if we were able to find information about the author outside of the reference document. ERG primarily verified information by looking for company/organizati on websites that confirmed the author’s affiliation with the UOG industryMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 17

Table 6

- 1. References

DCN Source Citation Source Flag a
SGE00629 Warner et al. 2013. Impacts of Shale Gas Wastewater Disposal on Water Quality in

Western PA. Environmental Science & Technology 47(20):11849

– 11857 A

SGE00782 U.S. EPA. 2012. (October 1). Available online at:

https://www.epa.gov/radiation/radionuclide

- basics

- uranium A

SGE00783 U.S. EPA. 2014. Thorium. (February 28). Available online at:

https://www.epa.gov/radiation/radionuclide

- basics

- thorium A

SGE00793 ERG. 2014. Unconventional Drilling/Hydraulic Fracturing and Natural Radioactivity

Webinar Notes. (July 3) C

SGE00795 U.S. EPA. 2012. About TENORM. (August 30). Available online at:

https://www.epa.gov/radiation/technologically

- enhanced

- naturally

- occurring

radioactive

- materials

- tenorm

. A

SGE00936 Understanding Radiation. Available online at:

https://www.epa.gov/radiation/radiation

- basics

. A

SGE00937 U.S. Environmental Protection Ag ency (U.S. EPA). 2011. Enhancing Radiological

Laboratory Testing for Radionuclides in Drinking Water Training. A

SGE00957 ERG. 2013. Environmental Engineering Support for Clean Water Regulations

Programmatic Quality Assurance Project Plan (PQAPP). A

SGE00958 ERG. 2014. Unconventional Oil and Gas (UOG) Supplemental Quality Assurance

Project Plan (SQAPP). A

SGE00968 Glatt, Dave; Tillotson, Steve. 2014. Contractor Selected for Cleanup of Filter Socks in

Noonan A

SGE00970 Donovan, Lauren. 2014. Bismarck Tribune Second dump site reported in Divide County. D
SGE00973 U.S. EPA. 2013. Radiation Glossary. A
SGE00974 U.S. EPA. 2014. D e v e l o pm e nt of Rapid Radiochemical M e th o d for Gross Alpha &

Gross Beta Activity Concentration in Flowback & Produced Waters from HF Operations A

SGE00975 Nelson, A. et al. 2014. Matrix Complications in the Determination of Radium Levels in

Hydraulic Fracturing Flowback Water from Marcellus Shale. A

SGE00977 USNRC. 2013. Measuring Radiation. A
SGE00978 PA DEP. 2014. PA DEP TENORM Study

- Update 2nd Quarter 2014 Update. A
SGE00979 PA DEP. 2013. Sampling and Analysis Plan Part II Quality Assurance Project Plan A
SGE00980 USGS. 2014. Trace Elements National Synthesis Project Radium Frequently Asked

Questions. A

SGE01018 Har ton, C. 2014. Radiological Dose And Risk Assessment of Landfill Disposal of

TENORM in North Dakota A

SGE01020 U.S. EPA. 2012. Radiation Protection Health Effects. A
SGE01028 PA DEP. 2015. Technologically Enhanced Naturally Occurring Radioactive Materials

(TENORM) Study Report. A

SGE01126 U.S. EPA. 2015. Assessment of the Potential Impacts of Hydraulic Fracturing for Oil

and Gas in Drinking Water Resources. ORD. A

SGE01181 ERG. 2016. Unconventional Oil and Gas (UOG) Drilling Wastewater Memorandum A
SGE01184 ERG. 2016. Unconventional Oil and Gas (UOG) Produced Water Volumes and

Characterization Data Compilation Memorandum A

SGE01188 U.S. EPA. 2016. Technical Development Document for Effluent Limitations Guidelines

and Standards for Oil and Gas Extraction. AMemorandum: Radioactive Material in the UOG Extraction Industry Wastewater

June 6 , 201 6 Page 18

Table 6

- 1. References

DCN Source Citation Source Flag a
SGE01 333 North Dakota. Regulation and Licensing of Technologically Enhanced Naturally

Occurring Radioactive Material Chapter 33

- 10

- 23

. A

SGE01334 ERG. 2016. Memorandum Providing a Crosswalk between Tables and Figures in the

Proposed and Final Technical Development Document for Effluent Limitations Guidelines and Standards for Oil and Gas Extraction

. A

a

— Source Flag A

- J ournal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes). Source Flag B

- D ocuments prepared by a verified source that include citation information (e.g., operator reports, vendor documents, university publications); Source Flag C

- Documents prepared by a verified source that do not include citation i nformation (e.g., operator reports, vendor documents, conference presentations); and Source Flag D

- Documents prepared by a source that could not be verified and that do not include citation information.