Application of Stable Isotopes In Environmental Investigations

Application of Isotopes in Environmental
Investigations

Thomas Butler PG, CHG, CEG
Senior Hydrogeologist/Geochemist
butler@ecologic-eng.com

El Dorado Hills, CA Nevada City, CA Rocklin, CA San Andreas, CA Stockton, CA Reno, NV

Why
Isotopes?
Potential Utility at
Land Disposal
Facilities
Spatial Variability

Adapted from Training Handbook for Disposal of Non-
Non-
Designated Waste to Land Systems:
Design, Operation, and Monitoring. Water Board Training
Academy, July 2004

Thomas Butler PG, CHG, CEG 2

Why
Isotopes?
Land Disposal
Facilities
Spatial Variability

WWTF Not Present When
GW Samples Taken

Adapted from Training Handbook for Disposal of Non-
Non-
Designated Waste to Land Systems:
Design, Operation, and Monitoring. Water Board Training
Academy, July 2004


Why
Isotopes?
Land Disposal
Facilities
Spatial Variability


Outline
What is an isotope?

Why is isotope geochemistry a useful tool in
investigating environmental phenomena?

Practical examples….


Fundamentals
Isotope – One of two or more forms of an element that have the same number of
protons (atomic number) however a different number of neutrons, and thus a different
atomic mass. May be stable or radioactive


Fundamentals
Isotope Ratio:
(R) = Heavy/Light

Stable Isotopes Expressed as:
δR = (Rsample/Rref. – 1)*1000
permil (‰)

From Kendall and McDonnnell, 1998


Fundamentals

From Clark and Fritz, 1997


Fundamentals
Why are stable isotope useful? – Fingerprinting (source) and Fractionation
(changes in the isotopic values)
Fractionation
Examples:
H2O –
Evaporation
NO3 –
Denitrification
Hydrocarbons –
Degradation

From Clark and Fritz, 1997


Fundamentals of Isotope
Geochemistry

from Clark and Fritz, 1997


Stable Isotopes of Water



*from Kendall and McDonnell, 1998


Application
Water Rights Appropriation, Washoe County,
Nevada


Water Rights Appropriation
Washoe County, Nevada

-15.8/-122


-60
WF-1
W3B
W-36
W5
Coyote
-70 Biddleman Well
Biddleman Spring
WG
WS
USGS Ave Truckee River USGS Ave. Truckee River
USGS 19
-80 USGS 20 Water Recharge
USGS 21
USGS 22
USGS 23
δ H (PERMIL, VSMOW)

USGS 24
USGS 26
-90 USGS 29
USGS 30
USGS 38
USGS 47
USGS 51
USGS 53
-100 Average Local Recharge
TRCC-1
TRCC-2
2

TRCC-3

-110

-120
Typical of Groundwater
Dominated by Precipitation Recharge

-130
-18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6
δ O (PERMIL, VSMOW)
18


Application
Salinity Impacts at a Land Disposal Facility,
Solano County, California


Application –
Solano County

Sub-Regional


Application – Solano County
Sub-Regional


Application –
Solano County
Sub-Regional


Butler, 2007
Sub-Regional


Sub-
Regional


Application –
Solano County
Local



PP-3



Combined Solute and Water Isotope Data
Valuable for:
Identifying Regional Mixing Related to Agricultural
Water Sources
Fingerprinting Salinity Sources (wastewater vs. non-
wastewater)
Quantification of Regional Salinity trends
Identification of processes/source influencing
compliance wells


Application
Salinity Impacts at a Land Disposal Facility,
Yolo County, California


Application –
Yolo County


Application – Yolo County



Combined Solute and Water Isotope Data
Valuable for:
Fingerprinting Salinity Sources at Compliance Wells
(percolated pond water vs. background source)
Identification of Groundwater/Surface Water Mixing
relationships
Quantification of Chemical Changes in Effluent during
Evaporation


Application
Water Supply Investigation, San Joaquin
County, California


Supply Well, San Joaquin County


δ18O δ2H
Well/Water Source Chloride (mg/l)
(permil, VSMOW) (permil, VSMOW)

Seawater 19400 0 0

Park Supply Well 36 -10.62 -77.4

ND-72M (Shallow) 12 -10.67 -77.6

ND-72M (Deep) 2160 -8.93 -69.2

This info was then used to model a theoretical
Isotope dataconcentration = 2140 mg/l at the
Cl indicates that 89% of water
(Very similar Deep is river water
ND-72M to the measured value)


Application
Land Disposal Facility, Stanislaus County,
California


Wastewater Treatment Plant – Conventional Aerated Pond
Treatment, San Joaquin County, CA



‐20

MW‐1 MW‐2 MW‐3 MW‐4 MW‐5 A‐Line Irrigation Ditch Effluent Reservoir Influent (composite) Water Supply

‐30

‐40
δ H (permil, VSMOW)

‐50
2

‐60

‐70

‐80
0 500 1000 1500 2000 2500 3000 3500 4000
Chloride (mg/L)



‐20
MW‐1 MW‐2 MW‐3 MW‐4
MW‐5 A‐Line Irrigation Ditch Effluent Reservoir
Influent (composite) Water Supply Evaporation Model (Closed)

‐30
Transpiration of Crops
Irrigated with Effluent Groundwater

‐40

‐50
2

‐60

Irrigated with Local Groundwater
‐70

‐80
0 500 1000 1500 2000 2500 3000 3500 4000
Chloride (mg/L)



‐20
MW‐1 MW‐2 MW‐3 MW‐4
MW‐5 A‐Line Irrigation Ditch Effluent Reservoir
Influent (composite) Water Supply Transpiration/Mixing Model Evaporation Model (Closed)

‐30
Irrigated with Effluent Groundwater

100%
‐40

80%

60%
‐50

40%
2

‐60 20%

0% Transpiration of Crops
Irrigated with Local Groundwater
‐70

‐80
0 500 1000 1500 2000 2500 3000 3500 4000
Chloride (mg/L)


Application
Water Supply Investigation, Mono County,
California


Hydraulic Connectivity of Well Supply
and Surface Water – Mono County,
California
Gull Lake
Reversed Creek - Upstream of Ski Area
Ski Area Well
Spring Across from Ski Area
Test Well 1
Test Well 2


California

Gull Lake hydraulically up gradient of
supply wells and springs.
Spring

Potential Are the springs and/or supply wells in
Production hydraulic communication with the Lake?
Wells

Will production from the well likely have an
impact on lake levels?

What are the sources (or other sources) of
water to the supply wells?
Surface
Water Location GWE
Monitoring Well 1 7,556 feet
Well 2 7,566 feet
Existing
Production
Gull Lake 7,602 feet
Well


California
Gull Lake
Ski Area Well
Spring Across from Ski Area
Test Well 1
Test Well 2


California


California
-100
Gull Lake
-105 Ski Area Well
Spring-Across from Ski Area
Test Well 1
-110
Test Well 2
δ 2 H (permil, VSMO W)

-115

-120

-125

-130
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Chloride (mg/L)


California
Pumping Tests (Well 1 and Well 2)
No response in observation well during
pumping test of either Well 1 or Well 2

7602 feet
No response in Spring during Well 1
7566 feet pumping test

7556 feet There was a response in the Spring
during Well 2 pumping test


Isotopes and Landfills
San Francisco Bay Area, California


Isotopes and Landfills


Isotopes and Mines
San Francisco Bay Area, California


Processes Influencing Acid Generation and
Metals Transport – Leona Heights Sulfur Mine,
Oakland, California


Oakland, California
Exposed waste rock and acid mine
drainage (Leona Heights Sulfur
Mine, Oakland, Ca)


Oakland, California

14

12
0%
10
δ OSulfate (permil, VSMOW)

8

6 25%
4
LHSM Alameda County, Ca

Pyrite Oxidation:
2 Stoichiometric Isotope-Balance Model:
50% 1. FeS2(s) + 3.5O2 + H2O = Fe2+ + 2SO42- + 2H+ (pH>4)
0 4. δ18OSO4 = XH2O(δ18Ow + εw) + (1 – XH2O)[0.875(δ18Oa + εa) + 0.125(δ18Ow + εw)]
-2
Fe2+ + 0.25O2 + H+ = Fe3+ + 0.5H2O
(Catalyzed by bacteria at pH <4)
18

5. XH2O = (δ18OSO4 – 0.125*δ18Ow – 11.5375)/(0.875*δ18Ow – 7.4375)
PA Coal Mines

-4 75%
3. FeS2(s) + 14Fe3+ + 8H2O = 15Fe2+ + 2SO42- +16H+
-6
100%
-8

-10
-16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10
18
δ OWater (permil, VSMOW)


Oakland, California

2.50 1200
Ferrous Iron
D isso lved F erro u s Iro n Mass F lu x (m m o l/m in )

Insolation
1000
2.00

800

In so latio n (W/m 2 )
1.50

600

1.00
400

0.50
200

0.00 0
4/25/02 0:00 4/25/02 12:00 4/26/02 0:00 4/26/02 12:00 4/27/02 0:00 4/27/02 12:00 4/28/02 0:00
Date/Time Sampled (Pacific Standard Tim e)


Oakland, California

pH Lake Aliso ORP Lake Aliso Insolation
8.10 1000

7.90 800

I n s o la tio n (W /m 2 )
O R P (m V ) a n d
7.70 600
pH

7.50 400

7.30 200

7.10 0
7/3/2002 0:00 7/3/2002 12:00 7/4/2002 0:00 7/4/2002 12:00 7/5/2002 0:00 7/5/2002 12:00 7/6/2002 0:00

Date/Time

Oakland, California

250 1200
Copper Manganese Zinc Insolation

198 198 1000
191
200 181

161 161
M a ss Flux (m g /m in)

800

Inso la tio n (W /m )
2
150

600

100
72 400
66 66
49 53 53
50
200

6.6 5.6 6.9 6.3 6.9 6.3

0 0
7/3/2002 0:00 7/3/2002 12:00 7/4/2002 0:00 7/4/2002 12:00 7/5/2002 0:00 7/5/2002 12:00 7/6/2002 0:00

Date/Time


Solute Isotopes/Other Tools

commons.wikimedia.org/wiki/File:Boric-acid-2D.png
http://www.kgs.ku.edu/Publications/pic14/pic14_1.html
http://etharelkatatney.blogspot.com/2008/06/bitter-pill-to-swallow.html


Source of Boron
Wastewater
Nonmarine evaporites
Borax/NaBO4 (-1 to +7‰)

from Hoefs, 2004


Application –
Solano County
Local



PP-3


Nitrate Source



Pharmaceuticals and PCPs


Rare Earth Elements

Anthropogenic
Gadolinium

Lack of Anthropogenic
Gadolinium


Source of Recharge and Age Dating
1.00
He
Percent Relative Decrease in Solubility

0.90

0.80
Ne
0.70
Typical USA
0.60 Groundwater
Temperature

0.50 N
O
Ar
0.40
Kr
0.30
Xe
0.20
0 10 20 30 40 50
Temperature (C)


Source of Recharge and Age Dating

Isotope/Compound Decay Product Half Life Issues/Deficiencies
(yrs)

Tritium (3H) Helium-3 (3He) 12.43 Accounting for excess air and crustal
sources (6Li + n = 3H + α)

Sulfur Hexafluoride (SF6) NA NA Accounting for excess air and
potential local sources

Chlorofluorocarbons (CFCs) NA NA Reduction of the CFCs has resulted
in limited uses for recent GW
Recharge

Krypton-85 (85Kr)
Krypton-85 (85Kr) Rubidum-85 (85Rb)
Rubidum-85 (85Rb) 10.76
10.76 Large volume of water (~100 L)
Large volume of water (~100 L)

Argon-39 (39Ar)
Argon-39 (39Ar) Potassium-39 (39K)
Potassium-39 (39K) 256
256 Large volumes of water
Large volumes of water
(~1000L); specialized analysis
(~1000L); specialized analysis


Fundamentals of Isotope Geochemistry

from Clark and Fritz, 1997 from U.S. Geological Fact Sheet 134-99


The End….

http://www.youtube.com/watch?v=t5ZFoU0S5iE&NR=1


Application of Stable Isotopes In Environmental Investigations

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