 ῌ
J. Jpn. Soc. Soil Phys.
!# 3
No. +**, p. /+- ,**/

 *ῌPer Moldrup**
The Emerging Role of Soil Physics in Environmental Engineering
Toshiko KOMATSU* and Per MOLDRUP*** Department of Biological and Environmental Science, Graduate School of Science andEngineering, Saitama University, ,// Shimo-Okubo, Sakura-ku, Saitama --2῍2/1*, Japan** Department of Life Sciences, Section for Environmental Engineering,
Aalborg University, DK-3*** Aalborg, Denmark
Abstract
Historically, soil physics research in Japan and worldwide has focused on soil-water physics
with a majority of studies on cultivated surface soils, and with the objective of optimizing watersupply to plants and minimize leaching of pesticides and nutrients below the root zone. Recently, transport, fate and emissions of greenhouse gases such as carbon dioxide and methane is anarea where rapidly growing environmental concerns about global warming and climate e#ects
has provided new challenges for soil physicists.
Another important challenge originates from the increasing problems in most urban areas withcontaminated sites, where soil and groundwater have been polluted with EICs (Environmental
Impact Chemicals) including gasoline and chlorinated compounds. To respond to these challenges, a broader focus in soil physics research and more emphasis on soil physical properties andprocesses in an environmental engineering perspective is needed.
Improved understanding and better predictive models together with reliable in-situ measurement methods for a larger variety of soil physical parameters can give soil physicists a major role
within the rapidly emerging research ﬁeld that combines environmental engineering and polluted
soil science ; soil environmental engineering.

Detailed knowledge of soil physical processes in all

three soil compartments (the soil-air, water and particle phases) is the platform for soil environmental engineering, including :῍ Realistic calculations of transport and fate of EICs at contaminated soil sites
῍ Risk assessments concerning indoor and outdoor air and groundwater pollution
῍ Development and optimization of remediation methods for soil and groundwater
In this perspective, future soil physics research should focus on chemical di#usion, sorption,
release, and convective transport in both the soil-water and soil-air phases and, also, evaluate thesigniﬁcance of particle-facilitated chemical transport through soil. As examples of less investigated soil physical parameters that are key parameters in soil environmental engineering, we
advocate the importance of gas and solute di#usivity, air permeability, and vapor sorption
coe$cients in relation to both risk assessment and to remediation by soil vapor extraction andpump and treat methods.
For soil environmental engineering purposes, not only the surface soil but the entire vadosezone between the soil surface and the groundwater table should be considered during studies of*   :

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6soil physical parameters.

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The dominating role of soil-physical processes in controlling andoptimizing biodegradation of pollutants during soil remediation should be investigated andhighlighted. With this emerging role of soil physics in environmental engineering combinedwith the rapid developments in process understanding and non-destructive measurement equipments, we are on the brink of an exciting new era in soil physics.
Key words : Soil Physics, Environmental Engineering, Fate and Transport of Chemicals, Environmental Impact Chemicals (EICs), Soil Remediation'+ῌ ΐῒ῔῕῎῍῏ῐῑ῎   

  
!"#$ῌFundamentals of Soil Physics. +32*

%& ' (    )*+' ,-.

ῌApplications of Soil Physics. +32*
ῌIntroduction to Soil Physics. +32,
ῌEnvironmental Soil Physics. +332

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4567 !8)(all Academic Press). F0 Jury and Horton K,**.L i Warrick

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General soil physical characteristics

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Relative number of polluted soil sites exceeding the environmental soil quality standard (datafrom Ministry of the Environment, ,**/).

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8

Fig. ,

Frequency of detected contaminants at +*2, polluted soil sites in Japan (,**-. -). (data from
Ministry of the Environment, ,**/).

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Fate and transport of Environmental Impact Chemicals (EICs).

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Fig. .

The three physical phases (solids, water, air) of a soil system. Environmental
Impact Chemicals (EICs) can distributeamong the three phases and can betransported by all three phases (colloidfacilitated transport, solute transport,
and gas transport).

Soil physical and physical-chemical processes and measurement methods

Processes in soils

Parameters

Measurement methods*

Unsaturated and satu- unsaturated and saturated TDR (Time Domain Reﬂectometry) and mini-TDR
rated water ﬂow
hydraulic conductivity
Solute dispersion and dif- dispersivity and solute dif- EC sensors (electrical conductivity sensors),
fusionfusivity
HPLC micro-column method**, and undisturbed
half-cell methods***
Air and gas transport

air permeability, gas di#u- air permeameter, GC micro-column method****,
sivityand gas di#usion chambers

Heat transport

thermal conductivity

heat probes

Physical / Physical-chem- linear or Freundlich sorp- batch and column set-ups, and HPLC and GC
ical sorption (hydropho- tion coe$cient, vapor sorp- micro-column methods****bic sorption)
tion coe$cient* Dane and Top (,**,), ** Komatsu (,**,), *** Olesen (,***), **** Yamaguchi (Komatsu) (+331).

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M* SVE ~IN: O\5

=1I 7Iversen, et al., ,**-8 \795[K=1
I 7Yamaguchi (Komatsu), et al., +3318 \7ῌ FPAB$ EICs ,& G<= 7Yamaguchi (Komatsu), et al, +3338 SVE ~I῍ :\ῌ\F 'XF`iHhi- 7Poulsen, et al., +332, +3338 Zly owI῎ Fῌ'X 7H8 ~I)&-., 

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I$ dI3 SVE ~I&&3e:$ 7e.g. Moldrup, et al., ,**- a, Poulsen, et al.,,**., Moldrup, et al., ,**., Moldrup, et al., ,**- b8* ῎ N:
~I@

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¸¹ῌYº : !"#$%&'()*+$./Fig. /

Schematic illustration of a Soil Vapor Extraction (SVE) system.

Fig. 0 11

Schematic illustration of a pump and treat system setup.

Yamaguchi (Komatsu), et, 0xy%z21I{()%bc|21

Komatsu, et al.,

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 !"#$%&'()*+,-.
!"/&0123456789:;<Society of America Journal, 01 (+) : -,῍.*.
Moldrup, P., Olesen, T., Komatsu, T., Yoshikawa, S.,
Schjῌnning, P. and Rolston, D.E. (,**- b) : Model-=>*-.2?@ABC@;D EF?@ing di#usion and reaction in soils : X. A unifying

G!"EF*+HI*J=. ABC@K-.

model for solute and gas di#usivity in unsaturat-!"(@L MNOPQN=KRST<ed soil. Soil Science, +02 (/) : -,+῍--1.
Moldrup, P., Olesen, T., Yoshikawa, S., Komatsu, T.

ῌ ῏ ῎ ῍and Rolston, D.E. (,**.) : Three-porosity model

Dane, J.H. and Topp, G.C. eds. (,**,) : Methods of Soilfor predicting the gas di#usion coe$cient inAnalysis : Part . : Physical Methods, SSSA Book

undisturbed soil. Soil Science Society of America

Series No. /, Madison, WI.

Journal, 02 (-) : 1/*῍1/3.

Hillel, D. (+332) : Application of Soil Physics to Re-

Motoshita M., Komatsu, T., Moldrup, P., de Jonge, L.

mediation of Hazardous Waste Sites, Envi-

W., Ozaki, N. and Fukushima. T. (,**-) : Soil con-ronmental Soil Physics, Part III, Chapter , : 011῍

stituent facilitated transport of phosphorus from

03*, Academic Press.

a high-p surface soil, Soils and Foundations, .-Iversen, B.V., Moldrup, P., Schjῌnning, P. and Ja-(-) : +*/῍++/.

cobsen, O.H. (,**-) : Field application of a porta-

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ble air permeameter to characterize spatial vari- V,**+W : *J!"T

ability in air and water permeability. Vadoseu !@{| No. 012 ῌῌ῍+3 : +++῍+,,.

Zone Journal, , : 0+2῍0,0.
Jury, W.A. and Horton, R. (,**.) : Soil Physics, 0th
edition, John Wiley & Sons.

EFU V,**.W : XY +0 Z[EF\]  V+331W : EF?@¡¢] p. 1-.

Olesen, T., Moldrup. P., Yamaguchi, T., Nissen, H.H.
http : //www.

and Rolston, D.E. (,***) : Undisturbed half-cell

env.go.jp/policy/hakusyo/hakusyo.php-?kid^

method for measuring the solute di#usion coe$-,+3

cient in unsaturated soil. Soil Science, +0/ (++) :EFUEF_(`aEFb V,**/W : XY +. Zc!"
deῌfghijkflmn*+deoLp6 http : //www.env.go.jp/water/report/h+0῍

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Pepper, L., Gerba, C.P. and Brusseau, M.L. (+330) :Pollution Science, Academic Press.
Poulsen, T.G., Moldrup, P., Worsten, H. and Jacobsen,*//index.html.
Kersting, A.B., Efurd, D.W., Finnegan, D.L., Rokop, D.

O.H. (,**.) : Predicting three-region unsaturatedJ., Smith, D.K. and Thompson, J.L. (+333) : Migra-

hydraulic conductivity from three soil-water re-tion of plutonium in ground water at the Nevada

tention points. Soil Science, +03 (-) : +/1῍+01.

Test Site. NATURE -31 (1 JANUARY) : /0῍/3.

Poulsen, T.G., Moldrup, P., Schjῌnning, P., Mas-

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Komatsu, T., Kawashima, H., Motoshita, M., Moldrup,smannn, J.W. and Aa. Hansen, J. (+332) : Gas permeability and di#usivity in undisturbed soil :Soil Vapor Extraction implications. ASCE Jour-P., Ozaki, N. and Fukushima, T. (,**,) Retarda-

nal of Environmental Engineering, +,. (+*) : 313῍tion of multiple Environmental Impact Chemi-

320.

cals in soils : Direct measurements by impulse

Poulsen, T.G., Moldrup, P., Yamaguchi, T., Schjῌnn-

type HPLC Micro-column method. Environmen-

ing, P. and Aa. Hansen, J. (+333) : Predicting soil-

tal Engineering Research -3 : +01῍.2,. VEF?@

water and soil-air transport properties and their78{|We#ects on soil vapor extraction e$ciency.

Moldrup, P., Yoshikawa, S., Olesen, T., Komatsu, T.
and Rolston, D.E. (,**- a) Air permeability in un-

Ground Water Monitoring & Remediation, +3(-) : 0+῍1*.

disturbed volcanic ash soils : Predictive model

Schelde, K. Moldrup, P., Jacobsen, O.H., de Jonge, H.,

test and soil structure ﬁngerprint. Soil Sciencede Jonge, L.W. and Komatsu, T. (,**,) : Dif-ῌ : 

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fusion-limited mobilization and transport of nat-

Environmental Engineering Research, -0 : .11῍ural colloids in macroporous soil. Journal of.2,.

Vadose Zone Hydrology, + (+) : +,/῍+-0.

Yamaguchi (Komatsu), T., Inoki, H. and Moldrup,

Soil Science Society of America (,**+) : Glossary

P. (+331) : Gas chromatography micro-columnof Soil Science Term, http : //www.soils.org/

method for measuring retardation of volatile or-sssagloss/.

ganic chemical gas transport in soils. JSCE Jour-

USACE (US Army Corps of Engineers) (+33/) : Military Programs Engineer Manuals, +++*῍+῍.**+,
http : //www.usace.army.mil/inet/usace-docs/
eng-manuals/cemp.htm.
Warrick, A.W. (,***) : Soil Physics Companion, CRC
Press.
Yamaguchi (Komatsu), T., Poulsen, T.G., Moldrup, P.

nal of Environmental Systems and Engineering//3 (VIII-,) : +-῍,,. 
Yamaguchi, T., Moldrup, P. and Yokosi, S. (+323) :Using breakthrough curves for parameter estimation in the convection-dispersion model ofsolute transport. Soil Science Society of America
Journal, /- (0) : +0-/῍+0.+.

and Fukushima, T. (+333) : Predictive model for
adsorption of volatile organic chemicals in soils.

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