(originally aired 07-26-12) U.S. EPA and many state agencies are investigating fracking in Marcellus Shale’s impact on environmental water quality. Public outcry has led to drafting legislation. Increased levels of bromide in drinking water systems correlate to higher levels of brominated disinfection byproducts. Trace metals (i.e., arsenic, selenium, lead), important constituents of flowback water, must be accurately determined for regulatory compliance, challenging due to high levels of dissolved salts which can cause physical and spectral interferences. Here, experts discuss monitoring and measuring anion concentrations in water from recycling impoundments, the typical constituents reported for Marcellus Shale fracking operations, flowback water preparation, and ICP-OES and ICP-MS metals analysis.

1. Anions and Metals Analysis for Waters
Impacted by Hydraulic Fracturing
Richard Jack, Ph.D.
Manager, Global Market Development
The world leader in serving science
1

2. Hydraulic Fracturing (Fracking) Controversy
2

3. Hundreds of Known Chemicals in Fracking Solutions
• Hundreds of chemicals in fracking solutions
• 50,000 mg/L salt (10–20x sea water)
• The EPA has narrowed the list of compounds down to less than 20.
• The EPA is in the process of developing analytical methods for these target compounds.
3

4. Pennsylvania Regulations for Wastewater from Fracking
• In lieu of the trace analysis described in Subsection b, the chemical
analysis of wastewater produced from the drilling, completion and
production of a Marcellus Shale or other shale gas well must include the
following: Acidity
Ethylene Glycol
pH
Alkalinity (Total as CaCO3)
Aluminum
Ammonia Nitrogen
Arsenic
Barium
Benzene
Beryllium
Biochemical Oxygen
Boron
Bromide
Cadmium
Calcium
Chemical Oxygen Demand
Chlorides
Chromium
Cobalt
Copper
Gross Alpha
Gross Beta
Hardness (Total as
CaCO3)
Iron – Dissolved
Iron – Total
Lead
Lithium
Magnesium
Manganese
MBAS (Surfactants)
Mercury
Molybdenum
Nickel
Nitrite-Nitrate Nitrogen
Oil & Grease
Phenolics (Total)
Radium 226
Radium 228
Selenium
Silver
Sodium
Specific Conductance
Strontium
Sulfates
Thorium
Toluene
Total Dissolved Solids
Total Kjeldahl Nitrogen
Total Suspended Solids
Uranium
Zinc
• Additional constituents that are expected or known to be present in the
wastewater.
*Note: All metals reported as total.
4

5. Monitoring Environmental Impact
• Public concern poses a challenge to environmental laboratories.
• Some contaminants do not have approved EPA analytical methods.
• Matrix issue—hypersaline fracking waters can affect analysis of certain
compounds.
• Robust analytical methods needed to assess environmental impact from
fracking processes.
• Following speakers will discuss inorganic analysis methods for anions
and metals.
5

6. Thermo Scientific Dionex Ion Chromatography (IC)
Systems for Anion and Cation Analysis
Reagent-Free™ IC (RFIC™) Systems
Dionex
ICS-2100
Dionex
ICS-4000
Dionex
ICS-5000
Dionex
ICS-1600
Dionex
ICS-900
Starter Line
IC System
Compact Design
Chem. Suppression
DCR Mode
6
Dionex
ICS-1100
Basic Integrated
RFIC System
Compact Design
Electr. Suppression
Integrated Sample Prep
Eluent Regeneration
Standard
Integrated RFIC
System
Compact Design
Electr. Suppression
LCD Front Panel
Column Heater
Integrated Sample Prep
Eluent Regeneration
Superior
Integrated
RFIC System
Compact Design
Eluent Generation
RFIC Gradient
Electr. Suppression
LCD Front Panel
Column Heater
Integrated Sample Prep
Capillary High-Pressure
Integrated RFIC System
Capillary HPIC™
Eluent Generation
RFIC Gradient
Multiple Detectors,
Including
Electrochemical (ED)
and Charge (QD)
Premier
Modular RFIC System
Capillary HPIC
Modular
Flexible
Single or Dual Channel
Eluent Generation
Proportioned and
RFIC Gradients
Multiple Detectors
Multiple Thermal Zones

7. Thermo Scientific Dionex IonPac Anion-Exchange
Columns
Column
Dionex IonPac™
AS19
0.4 × 250 mm
2 × 250 mm
4 × 250 mm
Recommended hydroxide-selective column for inorganic
anions and oxyhalides, e.g., trace bromate in drinking
water
Dionex IonPac
AS18
0.4 × 250 mm
2 × 250 mm
4 × 250 mm
High capacity hydroxide-selective column for the analysis
of common inorganic anions
Dionex IonPac
AS18-Fast
0.4 × 150 mm
2 × 150 mm
4 × 150 mm
Hydroxide-selective column for fast analysis of common
inorganic anions
Dionex IonPac
AS23
2 × 250 mm
4 × 250 mm
Recommended carbonate-based column for inorganic
anions and oxyhalides, e.g., trace bromate in drinking
water (better solution for Dionex IonPac AS9-HC users)
Dionex IonPac
AS22
7
Formats
Primary Application
2 × 250 mm
4 × 250 mm
Recommended carbonate-based column for fast analysis
of common inorganic anions (better solution for Dionex
IonPac AS14, AS14A and AS4A users)

8. Comparison of Hydroxide and Carbonate Eluent for
Separation of Common Anions
05
.
A
4
1
8
91
0
Column/Eluent: A) Dionex IonPac AS19
using hydroxide eluent
B) Dionex IonPac AS23
using carb/bicarb eluent
1
1
Detection:
7
µ
S
A
6
2
3
Peaks
5
02
.
07
.
B
4
1
µ
S
8
1
1
1
0
8
5
µg/L
11.3
5.1
9.5
• Both eluents show excellent anion
separation.
567
–01
.
0
1. Fluoride
2. Chlorite
8.8
3. Bromate
4.7
4. Chloride
5. Nitrite
6. Chlorate 13.5
7. Bromide
8. Nitrate
9. Carbonate
10. Sulfate
11. Phosphate
B
9
3
2
Suppressed conductivity
1
0
1
5
Minutes
2
0
2
5
3
0
• Trace anions are well resolved.
• Hydroxide does not show the water dip.

9. AA, ICP and ICP-MS—Speed and Detection Limit
> 1ppb
DL
Higher Cost
< 1ppt DL
ICP-OES
ICP-MS
60s for 10 elements
Speed
120s for 10 elements
Rugged Multielement
Technique
Sensitive Multielement
Technique
Furnace AA
20 mins for 10 element
Single Element
Technique
9
Flame AA
300s for 10 element
Ppm DL
Single Element
Technique
> 100ppt DL
Detection
Limit

10. Complete Inorganic Elemental Analysis
He
H
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
V
Rb
Sr
Y
Zr
Nb
Mo Tc
Cs
Ba
La
Hf
Ta
W
Re
Fr
Ra
Ac
Ce
Pr
Nd Pm Sm
Th
Pa
Cr
Mn
U
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Ru Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Os
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Pu Am Cm
Bk
Cf
Es
Fm
Md
No
Lw
Fe
Np
Ir
AA/ICP/ICP-MS
ICP/ICP-MS
ICP-MS
Not measurable
Unstable elements
IC
IC is also used for additional anions, such as oxyhalides, SO4 and NO3.
10

11. Anion Analysis of Water Associated with
Unconventional Natural Gas Extraction
John F. Stolz, Ph.D, Duquesne University, Pittsburgh, PA

12. What is Marcellus Shale?
www.getmoneyenergy.com/wp-content/uploads/2010/01/shale-gas-basins-in-usa.jpg

13. Horizontal Drilling and Fracking
http://app1.kuhf.org/userfiles/hydraullic_fracturing_natural_gas.gif

16. Produced Water
High Total Dissolved Solids (60–250,000 mg/L)
Chloride, bromide, strontium, barium
Gaudlip et al., 2008. SPE 119898

18. The System
 Thermo Scientific Dionex ICS-1100 with:

DS6 Heated Conductivity Cell

AS-DV Autosampler
 Thermo Scientific Dionex DAD-3000 UltiMate 3000 Diode Array
Detector (UV-vis)
 Thermo Scientific Dionex OnGuard II M Cartridge
 Thermo Scientific Dionex IonPac AS-22 Anion Exchange
Column

20. Running Conditions
Eluent:
4.6 mM sodium carbonate/
1.4 mM sodium bicarbonate
Flow Rate:
0.25 ml/min
Samples:
Filtered 0.22 um (PES filter0)
Run Time:
20 min
Conductivity
Range:
0–1500 uS/cm
UV-vis:
195 nm (ch 1), 200 nm (ch 2),
205 nm (ch 3), 215 (ch 4)

21. Standards (Retention Time):

Bromide (6.887 min)

Floride (3.377 min)

Chloride (4.847 min)

Nitrate (7.654 min)

Nitrite (6.201 min)

Phosphate (10.534 min)

Sulfate (11.781 min)

Arsenate (19.05 min)

Arsenite (4.357 min)

Monomethylarsonic acid (9.967 min)

Dimethylarsonic acid (2.623 min)

23. Five-Point Calibration Curves:
a: 0.5, 1, 2.5, 5, 10 ppm
Bromide, Floride, Chloride
b: 2.5, 10, 25, 50, 100 ppm
Nitrate, Nitrite, Phosphate, Sulfate
c: 10, 50, 100, 250, 500 uM
Arsenate, Arsenite, Monomethylarsonic acid,
Dimethylarsonic acid

26. Table 1: Anion data for impoundment water, coal mine effluent, and freshwater stream water
Unit
Conductivity
pH
Sulfate
Nitrate
Bromide
Chloride
Arsenic
uS cm-3
mg/L
mg/L
mg/L
mg/L
ug/L
Field Sample
Impoundment
Water
Sample #1
Field Sample
Impoundment
Water
Sample #2
Field Sample
Coal Mine
Effluent
Sample #3
Field Sample
Freshwater
Stream
Fonner Run
Field Sample
Freshwater
Stream
Bates Run
102,864
5.38
8.64
ND
255
30,683
BDL
61,477
5.67
10.21
ND
226
27,700
BDL
6,400
7.53
3,826
1.81
14.25
1,241
BDL
387
7.91
25.07
0.11
ND
1.29
BDL
476
7.67
24.46
0.58
ND
6.00
BDL
ND - not detected
J.L. Eastham, 2012
BDL - below detection limit

27. Conclusions
 The Dionex ICS-1100, equipped with the DS6 Heated
Conductivity Cell provides a rapid means for separation
and detection of anions (e.g., Cl, Br) commonly found in
flowback and produced water associated with
unconventional shale gas extraction.
 Produced water from Marcellus Shale is higher in
chloride and bromide but lower in sulfate, and can be
distinguished from coal wastewater and natural streams.
 The addition of the Dionex DAD-3000 UltiMate™ 3000
Diode Array Detector in tandem with the Conductivity Cell
allowed for the detection of additional anions, e.g., As(III),
and arsenic speciation.

28. Hydraulic Fracturing
Flowback Water Analysis
by ICP-OES and ICP-MS
Joelle Streczywilk
Senior Group Leader
Geochemical Testing

29. Outline







The importance of trace analysis of flowback water
Sample preparation
Choosing an analysis technique
Analysis using the Thermo Scientific iCAP 6500
Duo View ICP Spectrometer
Minimizing physical interferences
Managing spectral interferences
Summary

30. Importance of Flowback Water
Trace Analysis




Gas exploration and development is growing
quickly and analysis techniques should evolve with
the Marcellus industry.
Flowback water is the main source of wastewater
from Marcellus shale gas drilling.
Flowback water can be treated and reused or
treated and discharged.
Metals analysis is essential for many reasons:
–
–
–
Ensures that treatment processes are functioning properly.
Meets discharge or storage requirements.
Assesses the hazards that could be related to a spill or leak.

31. Sample Preparation





EPA Method 200.2 is adequate for most flowback
samples.
Use 1% nitric and 0.5% hydrochloric acid digestion
(a nitric only digestion may be preferred if analysis
will be conducted by ICP-MS).
Reduce sample to approximately 20% of original
volume at 85 °C.
Cover sample with watch glass and reflux for 30
minutes.
Fill to original volume with DI water.

32. Sample Preparation



Flowback waters can
be saturated with salts
and precipitation may
occur.
Precipitation will lead
to inaccurate results
for both major and
trace element analysis.
Avoid crystallization by
diluting the sample
prior to digestion.

33. Analysis Techniques



ICP-OES and ICP-MS
Governed by the elements of interest, detection
limits required and the makeup of the sample
The constituents and permitting needs of flowback
water vary greatly so analysis techniques should
be sample specific.

34. Flowback Water Analysis by ICP-MS


Uranium analysis should be conducted on the
ICP-MS because uranium is a heavy isotope with
a simple spectrum and a slight interference from
206Pb16O (ICP-OES: weak signal and severe
2
interference).
Many other analytes of interest may be analyzed
on the ICP-MS with caution due to interferences
and high total dissolved solids (TDS). The use of
reaction or collision cells can minimize or resolve
many interference issues.

35. ICP-MS Spectral Interferences

Isobaric overlaps: some isotopes occur at the
same mass number.
–
–

Choose and monitor alternate isotopes.
Correction equation
Polyatomic overlaps: dimers, oxides, hydrides, etc.
–
Dynamic or empirical correction equations (may not be
accurate depending on the intensity of the interference)

36. ICP-MS Physical and
Matrix Interference

High TDS (some flowback waters are over 10%
TDS)
–
–
–

Viscosity—consistent aerosol formation is desired
Plasma loading—reduces ions generated by the plasma
Instrument drift—clogs cones
Minimized by internal standards, robust plasma
conditions, keeping dissolved solids below 0.5%
–
Dilutions: introduce error, raise practical quantitation limit
(PQL), detector life

37. Flowback Water Analysis
by ICP-OES


Most analytes of interest in flowback water can be
analyzed accurately with ICP-OES.
iCAP™ 6500 Duo View ICP Spectrometer has the
advantage of viewing the plasma both axially and
radially.
–
Enables the analysis of trace metals at low and high
concentrations simultaneously

38. ICP-OES Line Selection

Line sensitivity
–
–
–
–
Is based on detection limit required.
Avoid lines that require complex spectral correction
algorithms.
Select a radial or an axial view of the plasma.
Line switching is available for analyte measurements that
are found at both high and low concentrations (extends
linear range).

39. Flowback
Example
on iCAP 6500
• Diluted prior to
digestion
• ^ and * on Barium and
Strontium: peak
saturation
• ChkFail: check table
limit (Ba, Sr, Ca, Li, Mg
and Na)
• Sodium defaulted to
the low line (linearity
and interfering element
corrections [IECs])
• RSDs less than 3% for
all analytes above the
MDL

40. Minimizing Physical Interferences





Avoidance: dilute if possible
High solids nebulizer to minimize “salting out”
effects (Noordermer v-groove)
Humidify argon stream
Intelligent rinse
Use of internal standard

41. Internal Standard Compensation

Plasma loading from flowback waters
–
Readings are generally suppressed
Calibration
Blank Cts/S
Flowback
Sample Cts/S
Internal Standard
Recovery
Low axial Sc
4122
3486
85%
High radial Sc
19812
17357
88%
High axial Sc
405400
313240
77%

42. Flowback Water and Calibration
Blank Comparison
Low axial Sc 227
Low axial Se 196

43. Managing Spectral Interferences

Background interference
–

Routine and relatively easy to deal with
Direct spectral overlap
–
Avoidance

–
Use different line(s)
Complete a full spectral interference study

Trace metals should be studied at a concentration of at least
1000 µg/mL of interferant

44. Interfering Element Corrections

IECs may be calculated, but should be checked
after every calibration.
–


Use multiple check solutions.
IECs must not be used if the interferer
concentration is above the linear range.
IECs should be calculated quarterly and with each
nebulizer or torch change.

45. Spectral Interferences



Spectral tables can be helpful but not
depended on.
A matrix study is also important for flowback
water sample analysis.
Conduct fullframe analyses of all views in use
(high radial, low axial, and high axial).

46. Low Axial View of a Flowback
Sample with Blank Subtraction

47. Fullframe of 1000 µg/mL Strontium

48. Summary





The complex matrices of flowback waters make
accurate trace analysis difficult.
ICP-OES analysis is more conducive to multielement determinations for both high and most low
analyte concentrations.
ICP-MS is required only for uranium, however it can
be used to determine most other elements as well.
Avoidance is the key with both techniques.
If avoidance is impossible, caution must be used in
every determination.