Simulation of Heavy Metal TrUse of Scale FacUse o Sca e acVariable Sorpt

Han Xiao1, Jürgen Böttc

1Institute of Soil Science, Leibniz Unive2Dept. of Environmental Sciences, Un

ransport in Unsaturated Soil: ctors to Quantify cto s to Qua t ytion Isotherms

cher1, and Jiří Šimůnek2

rsity of Hannover, Hannover, Germany

niversity of California, Riverside, USA

Spatial variability of heaSpatial variability of heaPrecipitationp

Water flow and

Object: Quantification of sorption 

avy metal transportavy metal transport

 solute transport

to quantify heavy metal transport

Footprint of scalingFootprint of scaling

Mill i il it f il t tMiller similarity for soil water reten

Tillotson & Nielsen functional norm

Boettcher scale factors for sorption

ti 1956ntion 1956

malization 1984

n 1997

increasing sorption intensity

Scaling rulesScaling rules

(Boettcher 199

Scaling of sorption isothScaling of sorption isoth

ReferencDer

Scale facDer

Der

Derpro

hermherm

ce sorption isothermrived from mixed soil samplesctorsrived from soil physicochemical

rived from mixed soil samples

rived from soil physicochemical perties

Scaling procedureScaling procedure

Di t liDirect scaling procedure

Calculated MeanCalculated Mean sorption isotherm

Calculated scale factors

I di t liIndirect scaling procedure

Sorption isotherm d i d f i d ilderived from mixed soil 

samples

Scale factors transformed  from soil properties using linear p p g

regression

Water flow and heavy mWater flow and heavy mmetal transportmetal transport Sampling locationSampling location

L i l d l d i l t iLuvisol developed in loess materiaGermany

source : Google

l i L th h Hl in Lathwehren, Hannover, 

e Maps

Laboratory worksLaboratory works Soil properties & FreunSoil properties & Freun

pH CECeff Corg sand clay

‐ % % %‐ % % %

MeanTopsoil 6.9 96.8 1.18 3.8 11

MeanSubsoil 7.2 72.9 0.31 3.3 12

% % % % %

CV*Topsoil 2 40 10 9 1

Subsoil 2 42 17 13 2Subsoil 2 42 17 13 2

Coefficient of variationUnit of K is [µg1‐nLn/kg], unit of n is [‐]

dlich parametersdlich parametersK K K

y silt Feox Alox Mnox n(Cd)

n(Zn)

n(C

% []^ [] [% [] [] [

1 85 2617 581 356 14070.81

74980.51

241.

2 85 2621 603 228 22710.80

135090.49

121.

% % % % % % %

12 4 4 10 347

245

36

10 5 6 17 33 17 410 5 6 17 6 7 9

Direct scaling procedurDirect scaling procedur

Cd Zn

e topsoile topsoil

Cu

ndirect scaling procedundirect scaling procedu

Adj. R2 =0.513 Adj. R2 =0

pH Ox Fe pH Corg

Cd αin Zn 

ure topsoilure topsoil

0.505 Adj. R2 =0.443

sand pH CEC Corg

αin Cu αin

Reference isotherm andReference isotherm andHeavy Horizon Sample Direct scaling proHeavy metal

Horizon Sample size

Direct scaling pro

R‐SI*

Cdtopsoil 50 13 S=1394C0.8

subsoil 50 16 S=2248C0.7

Zntopsoil 50 14 S=7482C0.5

subsoil 50 14 S=13638C0

Cutopsoil 50 5 S=245C1.33

subsoil 50 10 S=118C1.64

& coefficient of variation& coefficient of variationReference sorption isothermScale efficiencySorption isotherm derived from mixed sample

d Scale factorsd Scale factors

ocedure Indirect scaling procedureocedure Indirect scaling procedure

SE^Adj. R2 SImixed

#

%%80 85 10 0.513 S=1398C0.83

79 92 13 0.503 S=2229C0.77

51 88 11 0.505 S=8709C0.49

.49 75 7 0.248 S=15612C0.44

3 72 3 0.443 S=275C1.30

4 89 8 0.612 S=161C1.59

Modeling with HYDRUSModeling with HYDRUSInfiltration 250

SS0mm per year

Cμg/L

Tyr

Cd 100 500

Zn 8000 500

Cu 2000 100

Scenarios I with originaScenarios I with origina

Cd

Zn

0

Zn

0

Cu

0

l sorption equilibriuml sorption equilibrium

100 μg/L 

8000 μg/L μg

2000 μg/L 

Scenarios II with directScenarios II with direct 

Cd

Zn

0

Zn

0

Cu

0

scaling procedurescaling procedure

100 μg/L 

8000 μg/L μg

2000 μg/L 

Scenarios III with indireScenarios III with indire

Cd

Zn

0

Zn

0

Cu

0

ect scaling procedureect scaling procedure

100 μg/L 

8000 μg/L μg

2000 μg/L 

ComparisonComparison

CdCdI

II

II

•Cu

•

ZnZn

I

Between different scenariosScenario I > Scenario II > Scenario Between different heavy metals

Zn(88%) > Cd (85%) > Cu(72%)

SummarySummary

h t l t t i b i lheavy metal transport is obviously

Direct scaling procedure: scale factvariability of heavy metal transporCu.Cu.

Indirect scaling procedure: predictIndirect scaling procedure: predict

i bl variable. 

tors can describe the spatial t well for Zn, not so well for Cd and 

ion accuracy must be improvedion accuracy must be improved.

Thanks for your attentioThanks for your attentioonon

Input α in HYDRUS 2Dput α USwith Cd direct scaling