Document jyGmBZjj0r8JXorK991dO261N
SOIL ADSORPTION - REVISED
TEST SUBSTANCE
Identity:
Perfluorooctanesulfonate; may also be referred to as PFOS or FC-95. (1Octanesulfonicacid, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-, potassiumsalt, CAS # 2795-39-3)
Remarks: The test substance is a white powder. Sample was re-crystalizedfrom a
productionlot of FC-95. Purity determined to be 97.9% by LC/MS, IH-HMR, 19F-NMR and elemental analyses techniques.
METHOD
Method: Based on OECD 106
GLP (Y/N): Yes Year completed: 2001. Amended report issued 2002 Statistical methods: Statisticalanalysis and plottingof the data was done according to OECD Method 106 using Microsoft Excel. Temperature: Room Temperature (19-30C) Stock and test solution preparation: The test concentrationsand conditionswere determined in a Preliminary experiment. For the definitiveexperiment, test solutionswere made by dilutinga stock solutionof un-radiolabeled Perfluorooctanesulfonateto a final test substance concentration of approximately 0.5 mg/L in aqueous 0.01 M CaCI2.
Soil Characteristics:
SoilClass
Clay
I ClayLoam
I I SandyLoam
',
I'
River Sediment
Source
KittsonCounty, MN
GrandForks CountyN, D
GrandForks CountyN, D
GrandForks CountyN, D
Lot Number
00-2407
00-2405
99-2564
00-2406
Physical Description
1.00mmair-
1.00rnmair-
1.00mmair- 1.00mmair-
dried0, -6"deep dried,0-6"deep dried,0-6"deep dried,0-6"deep
% Organic Carbon
% Sand
% Silt
% Clay CEC (meq/100g)
2.6% 16% 22% 620/0 54.5
2.6% 21% 46% 33% 24.7
2.8% 58% 220/0 200/0 23.3
1.3% 390/0 420/0 19/o 17.5
pH in0.01M
7.2
6.0
7.81
7.7
CaClz
Domestic Sludge
NIST,from DePnOveTrW,CO
2781
200 mesh, osvteenr-idlizrieedd,
Not analyzed.
Not analyzed
Not analyzed
Not analyzed
Not analyzed
Not
analyzed
1Value is for pH in water not pH in 0.1M CaCI2
Test Conditions:
Adsorption Kinetics: Replicatestudysamplescontainingthesoils(orsedimentsor sludges)wereequilibratedby shakingforat least12 hoursat roomtemperaturewith0.01 M CaCI2. Studysamplesweredosedwiththetestsubstanceat approximatel0y.5 mg/L andplacedonan orbitalshaker. Replicatesetsof thesestudysampleswere removedat designatedtimepointsthroughouat 48 hourtimeperiod.Studysampleswerethen preparedandanalyzedforthetargetanalyte.The adsorptionkineticswere determined usingthisdata.The lastsetof studysamples(48 hour)were savedand usedfor the desorptionkineticsportionof themethod.
Desorption Kinetics (One concentration): Afterthe adsorptionkinetics experimentt,he48 hourstudysampleswerecentrifugedand theaqueousphase removed. The volumeofsolutionremovedwas replacedbyan equalvolumeof0.01 M CaCI2withoutestsubstance.The newmixturewasagitateduntilthedesorption equilibriumwas reached, Duringa 48-hourperiod,at definedtimeintervalss, mall aliquotsof theaqueousphasewere removedand analyzedforthetargetanalyte.The desorptionkineticswere determinedusingthisdata.
RESULTS
Soil Type
Clay Clay Loam
Loam IRhm"Sediment DomestScSludge
Adsorption Kinetics of PFOS, 1:5 Soil:Solution Ratio, 48 Hour Time Point
Average Distribution coefrmient, Ka, L/Kg
Percentage of Organic Carbon in
Soil
Average Organic Carbon normalized Adsorption Coefficient, K=,=,L/Kg
18.3
2.8
704
9.72
2.6
374
35.3
Z8
7.42
1.3
1260 571
<0.120
Not available
Not calculable
The data indicatethatadsorptionoccurredwithinthefirstfew hoursofexposureand the testsubstanceconcentratiodnidnotvarysignificanUayfter16 hours.
Apparent Desorption Kinetics of PFOS, 1:5 Soil:Solution Ratio, 48 hour Time Point
So_Ty_
I_rpUo, CodrcientK, ,,,=U_
C_
47.1
Clay Loam
15.8
Sandy Loam
34.9
River Secllme_
10.0
Dorm==Skk,Jge
<237
The riversedimentdisplayedthe mostdesorptionat 39% after48 hours,The sludgesamplesdid not desorba detectableamountof testsubstance. Desorptionthat didoccurwas accomplished ratherquick/y;afterthe 8 hourtime pointthe test substanceconcentrationdid not vary significanlly.
Adsorption Isotherms
sobtype
Clay ClayLoam
LogKa_F
1.40 1.15
KLa/=KFg(1)' 25.1 14.0
Regress1io/nnconstant, 0.884 0.841
RegressionnConstant, 1.13 1.19
SandyLoam
1.45
28.2
0.829
1.21
RiverSediment 0.939
8.70
0.989
1.01
Sludge 2.53
338
1.26
0.795
(1) FreundlicahdsorptiocnoefficienTt.heunitsfortheisothermassumtehatthetermn=l. Moreaccurateltyh,e unitsare(pgl"ltn(L)_'_Kg'_)
Desorption Isotherms
SoilType Clay
LOgKd=F KL_/=KFg(1)' Regressi1oInnConstant,
2.02
105
0.860
RegressionnConstant, 1.16
ClayLoam
1.78
60.2
0.954
1.05
Sandy Loam RiverSediment
1.97 1.65
94.0 44.6
0.985 1.02
1.02 0.981
DomestiScludge 3.50
3130
0.977
1.02
(2) (]) F_el.md]ichdesorptloncoef6cJe'_L . Theunitsfortheisothermassumtehatthetermn=l. More accurateltyh,eunitsare(pgl"l/n(L)l_Kg'l)
Freundlichadsorptionisotherms relate the amount of test substance adsorbed on the soil to the amount present in the aqueous solution at equilibrium. The values calculatedfor the regressionconstant indicatethat the data obtainedfor the test substance over two orders of magnitude is slightlynon-linear.
CONCLUSIONS
Perfluorooctanesulfonate(PFOS) appeared to adsorb to all of the soillsedimentlsludge matrices tested. In either case, adsorption or desorption, an equilibriumis achieved in less than 24 hours,with substantialadsorption (>50%) occurring in some of the time 0
samples after approximately 1-minuteof contact.
Submitter. 3M Company, Environmental Laboratory,P.O. Box 33331, St. Paul, Minnesota, 55133
DATA QUALITY
Reliability: Klimisch ranking 1.
REFERENCES
3M Technical Report "SoilAdsorption/DesorptionStudy of Potassium Perfluorooctanesulfonate(PFOS)'. Mark E. Ellefson, Project Number E00-1311, Final Report Completion Date June 4, 2001. Amended Report CompletionDate May 24, 2002.
OTHER
Last Changed: June 12, 2002