INL RESEARCH & DEVELOPMENT

Securing the Nationʼs 

energy, natural 

resource, sustainability, 

and security needs requires 

significant advancement in 

understanding the interactions between fluids, natural 

materials, and contaminated 

media. INLʼs Geochemistry 

Research Group is advancing the scientific basis for 

addressing societyʼs most 

critical problems by developing fundamental understanding of coupled processes in 

complex subsurface environments, and scaling interactive 

biogeochemical processes 

from laboratory experiments 

to field applications.

Areas of research

Fluid flow and mineral precipitation/dissolution

The rate of fluid flow through 

porous and fractured media 

depends on the nature of 

pore space. Pore space can 

be drastically altered by the 

formation of precipitates or 

the dissolution of minerals. 

Such precipitation reactions 

are often undesirable because 

they can clog the aquifer and 

hinder the delivery of amendments into contaminated aquifers or impede the extraction 

of potable water or energy 

from subsurface reservoirs. 

INLʼs Geochemistry Group 

studies coupled flow and mineral precipitation to determine 

better methods for controlling 

the precipitation and flow of 

fluids in the subsurface. Such 

controls will improve remediation strategies and optimize 

energy extraction. INL is 

investigating the potential use 

of nested dipole well arrays to 

deliver and mix fluids in the 

subsurface. The application 

of biologically 

mediated hydrolysis of urea is 

also studied to 

control the rate 

and distribution 

of calcium carbonate precipitation and the 

co-precipitation 

of contaminants.

Pertubation 

geochemistry 

using reactive gases

Perturbation 

geochemistry is 

the deliberate and 

transient manipulation of 

subsurface chemistry to effect 

a lasting change on subsurface 

properties that persists when 

the system returns to ambient conditions. Introducing 

liquid solutions to the vadose 

zone to generate the necessary 

chemical transitions might 

mobilize the contaminants 

deeper into the vadose zone. 

Further, small-scale preferential flow in the physically 

and chemically heterogeneous 

media results in the amendments being inadequately 

distributed. Another method 

of perturbing vadose zone 

geochemistry is to manipulate 

the composition of soil gas. 

Diffusion coefficients of gases 

are orders of magnitude larger 

than aqueous diffusion coefficients; thus, the amending 

gases can be rapidly distributed in the subsurface and the 

scaling of laboratory results 

to field-scale vadose zone 

problems is more reasonably 

attainable. Researchers are 

determining the efficacy of 

applying such gaseous amendments to coprecipitate Sr. 

Decontamination of 

building surfaces

The Geochemistry Group 

has been working with other 

INL researchers to combine 

modeling, laboratory, and engineering expertise to develop 

new approaches for removing 

up to 99.9% of radioactive 

fallout from common building 

material surfaces – many of 

which are made of geologic 

materials. Geochemical modeling of laboratory experiments indicates that much of 

the decontamination process 

is limited by mass transfer 

from the bulk material to the 

surface of the building material. Based on these results, 

new techniques are being 

developed to improve and 

accelerate decontamination of 

common building materials.

In-situ treatment of arsenic

Arsenic is a naturally occurring toxic substance that can 

appear in drinking water supGeochemistry Reseach

Mesoscale column for measuring 

vadose zone CO2 transport.

Experiment to create mixing zone where 

solution is supersatured with calcite (at left); 

and tomographic image of calcite precipitation 

at the interface (at right).
INL RESEARCH & DEVELOPMENT

05-GA50193-51

For more information

INL is a U.S. Department of Energy 

national laboratory operated by 

Battelle Energy Alliance

plies. In response to health 

concerns from exposure to 

arsenic in drinking water, the 

Environmental Protection 

Agency is lowering the arsenic drinking water standard 

from 50 μg/L to 

10 μg/L. This new standard 

will impact many water 

providers in the western 

U.S., particularly in regions 

that depend on groundwater. 

INLʼs Geochemistry Group is 

developing cost-effective in 

situ methods to lower arsenic 

concentrations in water supply wells so wells with more 

than 10 mg/L arsenic will 

meet the new standard.

Geochemical reactivity in 

variably saturated 

porous media

Experimental package with 

column (at left) and fraction 

collector (at right) used in 

geocentrifuge vadose zone 

reactivity experiments.

Improved understanding 

of contaminant migration 

processes through the vadose zone is required for 

DOE to provide defensible 

computational models, better 

define long-term stewardship 

requirements, and help design 

effective barriers to vadose 

zone contaminant migrations. 

Conceptual models of contaminant migration in heterogeneous, variably saturated, 

porous media are improving. 

One aspect the INL investigates is the dependence of the 

reactivity in variably saturated 

porous media being dependent on the moisture content 

of the medium. A key and 

novel aspect of the proposed 

research involves INLʼs new 

two-meter geocentrifuge. 

This experimental approach 

using a geocentrifuge has 

distinct advantages over conventional methods. First, data 

is collected over much shorter 

time periods than conventional one-gravity techniques, and 

results in a more complete 

evaluation of various chemical conditions and materials. 

Second, controlling acceleration of the sample allows 

manipulation of the water 

content and the velocity in the 

soil columns.

Carbon sequestration

Emerging concern about the 

connection between global 

climate change and CO2 emissions has generated interest 

in better carbon management 

– including sequestration in 

subsurface geological formations. INL in collaboration 

with Montana State University, the University of Idaho, 

and Battelle Pacific Northwest 

Division, has embarked on 

a multi-year investigation of 

sequestration in mafic rocks 

and enhanced coal bed CO2

sequestration. The program 

will result in a field pilot demonstration.

Dr. George Redden 

Geosciences Research

(208) 526-0765

George.Redden@inl.gov

Dr. Mark Ankeny 

Geosciences Manager 

(208) 526-5748 Mark.

Ankeny@inl.gov

Experimental package with column (at left) and fraction collector 

(at right) used in geocentrifuge vadose zone reactivity experiments.