Inorganic carbon and CO2 from karst springs and mine waters · 2018-03-07 · Geomorphology and...

WEST VIRGINIA UNIVERSITY DEPARTMENT OF GEOLOGY AND GEOGRAPHY

Inorganic carbon and CO2 from karst springs and mine waters

Thermal-mineral Spring

Karst SpringCoal mine drainage

PCO2 pCO2

mg-CO2/L

mg-C/L

mM-CO2mM-DIC

ePCO2

eCO2

Log PCO2

Alk

TAlk

Dorothy J. Vesper


Acknowledgements

My (Mostly) Willing CO2 discussants: Harry Edenborn (DOE-NETL), Ellen Herman (Bucknell Univ.), Charles Cravotta (USGS), Gwen Macpherson (Univ. Kansas), Louis McDonald (West Virginia Univ.), Rosemary Capo (Univ. Pittsburgh), my students (posters today), Bucknell students, PITT students….

Multiple funding sources: WVU Appalachian Freshwater Initiative (funded by the National Science Foundation under Award Number 1458952).

National Energy Technology Laboratory’s Regional University Alliance (NETL-RUA), a collaborative initiative of the NETL, under the RES contract DE-FE0004000.

Tortuguero Spring,Vega Baja, Puerto Rico


1-slide primer on CO2 – H2O SystemLo

g [s

pec

ies]

6.3

5

10

.33

H2CO3* HCO3- CO3-2

H+ OH-

DICDissolved inorganic carbon (DIC):

𝐷𝐼𝐶 = 𝐻2𝐶𝑂3∗ + 𝐻𝐶𝑂3

− + [𝐶𝑂3−2]

[H2CO3*] = [H2CO3]aq + [CO2]aq

But [CO2]aq >> [H2CO3]aq so

[H2CO3 *] [CO2]aq

Alkalinity: The equivalents per liter of acid (eq/L) to titrate to the CO2-equivalence point in the CO2-H2O system:

𝐴𝑙𝑘𝑎𝑙𝑖𝑛𝑖𝑡𝑦 = 𝐻𝐶𝑂3− + 2 𝐶𝑂3

−2 ≅ [𝐻𝐶𝑂3−]

In eq/L, assuming carbonate alkalinity controls


2nd slide of 1-slide primer on CO2 – H2O System

pHDICAlkalinity (carb)H2CO3*HCO3

-

CO3-2

CO2(aq)PCO2

If you know 2 …. you know them all

To speciate the CO2-H2O system (that is, to know all of these)


Why do CO2 & DIC concentrations matter?

• Mineral solubility … cave geology

• Photosynthesis-respiration cycles (connects organic & inorganic cycles)

• Terrestrial inorganic carbon balances >>>>


Terrestrial inorganic carbon balances

DICATMOSCO2 from atmosphere

(including soil gas)

DICGEO

DIC released from rocks (geologically

sequestered carbon)

Ground Water

Dissolved CO2

HCO3

(alkalinity)

Surface Water

pH

low

>6

Released to atmosphere

Dissolved export from

watershed

Sulfuric acid can drive this


S-driven cave formation – Carlsbad, Lechuguilla, Frasessi

Lechuguilla Caves (NPS) Carlsbad Caverns (Wikipedia)

Grotto di Frasessi, Italy


Measuring DIC and CO2 in water

• Lab analysis of DIC

• Back calculate PCO2 from carbonate equilibria • DIC

• Alkalinity

• Field measurements using meters, CarboQC

From alkalinity & pH:

𝑃𝐶𝑂2 =𝑎𝐻 𝛾𝐻𝐶𝑂3

− 𝐻𝐶𝑂3−

𝐾𝐶𝑂2 𝐾1

From DIC & pH:

𝐶𝑂2 (𝑎𝑞) =[𝐷𝐼𝐶]

1 +𝐾1

𝑎𝐻 𝛾𝐻𝐶𝑂3+

𝐾1 𝐾2𝑎𝐻2 𝛾𝐶𝑂3

Assumptions, adjustments, potential for loss


Can we take direct field CO2 measurements?

• NDIR detection systems

• CarboQC

https://www.instrumentation2000.com/vaisala-gm70d.html

https://www.anton-paar.com/be-en/products/details/filling-device-pfd/

https://www.marinetechnologynews.com/news/turner-designs-launch-sense-513082

Fink et al. (2017) Identifying hysteresis patterns by detecting trends in calculated and directly measured CO2

concentrations (GSA Poster)Anton Paar CarboQC

Vaisala NDIR Sensor

Turner C-Sense (NDIR)

Vaisala

Turner


Comparing methods for some local mine waters

Calculated Alk > Measured Alk

BUT…Location #8 has Alk=0 and CO2 = 3.13 mM


CO2 measured/estimated in some different settings

• ZERT: Kharaka et al. 2010• Travertine: Pentecost 2005• Coal mines: Mayo et al. 2000;

Vesper et al. 2016• Mineral springs: Cartwright et

al. 2002• Chymayo: Keating et al. 2010• Volcanic springs: Chiodini and

Frondini 2001• Yellowstone gysers:

Nordstrom Darrell et al. 2005• Karst springs and streams:

Vesper et al. 2009Zert

Site

Trav

erti

ne

Co

al M

ine

s

Min

eral

Sp

r

Ch

ymay

o

Vo

lcan

ic S

pr

Yello

wst

on

e

Kar

st S

pr

Kar

st s

tr

CO

2(m

M)

Atmos.Equilib.


Coal mines in PA and WV (Vesper et al. 2016)

Atmos.Equilib.(0.38 mM)


What is the range of CO2? How variable is it?

Lamberts Run

Wingfield Pines

Marian Meadows & Lynn


Thoughts moving forward.

• CO2 has been used as a useful means for understanding flow in karst for generations – but there are more applications

• Letting sulfuric acid drive carbonate dissolution has greater impact on carbon cycling then letting carbonic acid drive dissolution.

• We need better tools for measuring CO2 in water

• Mine waters sulfuric-acid formed cave systems (geomicrobio?)

• We don’t understand much about how S-C-pH systems change spatially, temporally, or along a flowpath


Units and terminology – a special request

PCO2 vs. pCO2

Px is the partial pressure of gas x

pX = -log [X]

(pH, pOH, pKa, pe…)


Thank you

Gas bubbles at Old Sweet Spring

[CO2] ~ 300 mg-CO2/L[CO2] ~ 6.8 mM CO2

[CO2]~ 82 mg-C/L

PCO2 ~ 0.2 atmLog PCO2 ~ -0.70ePCO2 ~ 636 (assumes 10-3.5 atm)

pCO2 = -log[6.8] = -0.83


References

• Cartwright I, Weaver T, Tweed S, Ahearne D, Cooper M, Czapnik K, Tranter J. 2002. Stable isotope geochemistry of cold CO2-bearing mineral spring waters, Daylesford, Victoria, Australia: sources of gas and water and links to waning volcanism. Chemical Geology185: 71-91.

• Chiodini G, Frondini F. 2001. Carbon dioxide degassing from the Albani Hills volcanic region, Central Italy. Chemical Geology 177 (1-2): 67-83.

• Deffeyes KS. 1965. Carbonate equilibria: a graphic and algebraic approach. Limnology and Oceanography 10 (3): 412-426.• de Montety V, Martin JB, Cohen MJ, Foster C, Kurz MJ. 2011. Influence of diel biogeochemical cycles on carbonate equilibrium in a

karst river. Chemical Geology 283 (1–2): 31-43.• Hunt CW, Salisbury JE, Vandemark D (2011) Contribution of non-carbonate anions to total alkalinity and overestimation of pCO2 in

New England and New Brunswick rivers. Biogeosciences 8(10):3069-3076• Keating EH, Fessenden J, Kanjorski N, Koning DJ, Pawar R. 2010. The impact of CO2 on shallow groundwater chemistry: observations

at a natural analog site and implications for carbon sequestration. Environmental Earth Science 60 (3): 521-536.• Kharaka Y, Thordsen J, Kakouros E, Ambats G, Herkelrath W, Beers S, Birkholzer J, Apps J, Spycher N, Zheng L, Trautz R, Rauch H,

Gullickson K. 2010. Changes in the chemistry of shallow groundwater related to the 2008 injection of CO2 at the ZERT field site, Bozeman, Montana. Environmental Earth Sciences 60 (2): 273-284.

• Mayo AL, Petersen EC, Kravits C. 2000. Chemical evolution of coal mine drainage in a non-acid producing environment, Wasatch Plateau, Utah, USA. Journal of Hydrology 236 (1-2): 1-16.

• Nordstrom DK, Ball JW, McCleskey RB. (2005) Ground water to surface water: chemistry of thermal outflows in Yellowstone National Park. In: Inskeep WP, McDermott TR (eds) Geothermal Biology and Geochemistry in Yellowstone National Park. Montana State University Thermal Biology Institute, Bozeman, MT, p 73-91

• Palmer AN 2007. Cave Geology. Dayton, OH: Cave Books.• Pentecost A 2005. Travertine. Berlin: Springer-Verlag.• Vesper DJ, Grand RV, Ward K, Donovan JJ. 2009. Geochemistry and implications for structural control in a spring-dense karst

watershed, the Appalachian Great Valley, West Virginia, USA. Environmental Geology 53 (3): 667-678.• Vesper DJ, Moore JE, Adams JP. 2016. Inorganic carbon dynamics and CO2 flux associated with coal-mine drainage sites in

Blythedale PA and Lambert WV, USA. Environmental Earth Sciences 75 (4): 340.• White WB 1988. Geomorphology and Hydrology of Karst Terrains. New York: Oxford University Press.

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Inorganic carbon and CO2 from karst springs and mine waters · 2018-03-07 · Geomorphology and...

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