Document 91Dz8o4gBmkg3gYNOV2nnLZv5
SOIL ADSORPTION
TEST SUBSTANCE
Identity:N-methylperfluorooctanseulfonamidoethanolm;ay alsobe referredtoas N-MEFOSE Alcohol,FC-790, or FM-3925. (1Octanesulfonamide,N-methyl-1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8heptadecafluoro-N-(2-hydroxyethyClA)S-,# 24448-09-7)
Remarks:
Materialisan off-whitew,axy solid.Sample purityand lot number were notrecorded.
METHOD
Method: Adsorption-desorptiosntudiesdeveloped usingprocedures
describedby Davidson, 1976 and Hamaker, 1975. GLP (Y/N): No
Year (study performed): 1979
Statisticalmethods:
Statisticaalnalysisand plottingof the data was
done withthe MINITAB package ofthe 3M TRAC computer service.
Temperature: 16-190C duringthe 24-hoursofwrist-actiosnhaker
exposure.
Stock and testsolution preparation: The stocksolutionused was an
aliquotfrom the24-hour sample taken duringthewater solubilisttyudyon
N-MEFOSE Alcohol.This solutionwas preparedby theViethmethod and
gave a concentrationof2.16 mg/L. Test solutionwsere made by diluting
aliquotsof thestocksolution.
Remarks field: The Brilslandy loam soilwas characterizeads having
57% sand, 36% silt7,% clay,2.5% organicmatter,2.2% organiccarbon,
withpH 6.5 and cationexchange capacityof 15.3meq./l00 g. Standard
solutionsof N-MEFOSE alcoholwere prepared indeionizedwater at
concentrationsof2.16 mg/L, 1.21 mg/L, 0.691 mg/L, 0.389 mg/L, 0.216
mg/L, and 0.022 mg/L. Fortymi ofeach solutionwas shaken with5 gram
samples ofthesoilina 50 ml glasscentrifugteubesfor24 hours in
duplicateon a wristshaker at room temperature(16-190C).
Desorptionextractionwsere performed withdeionizedwater afterthe adsorptionphase ofthe experiment.The samples from theadsorption -anddesorptionexperimentswere centrifugedindividualalty3000 rpm for 30 minutes,and each supernatantsolutionwas decanted offintoglass sample vials.
Supernatantsolutionswere analyzed by extractinwgithethylacetateand runningGC.
RESULTS
K: 77 K..: 3,500*
Remarks field: The lineasrhape oftheadsorptioinsothermindicated thatN-MEFOSE alcoholadsorptionon soilwould be independent of concentrationinsolution.
The studyreporthad calculatedusing theformula:Kc = 100 K/% organiccarbon.
CONCLUSIONS
The studysubstance isexpected toexhibitlow mobilityinthe kindofsoil tested.
Submifter: 3M Company, EnvironmentalLaboratory,P.O. Box 33331, St. Paul,Minnesota,55133
DATA QUALITY
ReliabilityK:limischranking3. Study isusingan inaccuratesolubility value and thepurityofthe testsubstance isnot sufficientclhyaracterized. The analyticamlethodology was not validatedt,hereforethereisno way to evaluatethe accuracyofthe reportedanalyticarlesults.Itwas noted in the reportthata high percentage of FM 3925 was adsorbed onto the glass used intheexperiment.No attemptwas made to correctforthislossof testsubstance inthe calculationosfsorptiontosoil.The ViethMethod of -perpadnga saturatedsolutionwould disproportionatedliyssolvethe more solublecomponents of N-MEFOSE alcoholwhich isnota pure material. The studywas notperformed induplicatea,nd the soilwas not analyzed toverifythe amount remaining.Additionalltyh,e followingare summarized comments made by ProfessorStephen Boyd, Michigan StateUniversity:
Use ofoven driedsoilsnot recommended. Should be air-drieadnd characterizedformoisturecontent.
Use ofdeionizedwater fordesorptionexperimentsisnot recommended as itcauses the soiltodisperse.Use diluteCaC12-
Ethylacetate extractionot validated.
Did not establishthatthe sorptionisothermislinear.
There isno evidenceforelectrostatfiocrcesbeing involvedinsoilbinding of FM 3925.
REFERENCES 3M TechnicalReport "AdsorptionofFM-3925 on Soil."S.K. Welsh and C.H. Schrandt,Project9970612631 Fate ofFluorochemicals,Report No. 013, March 22,1979. Review ofTechnicalReport Summary. Adsoprtionof FM 3925 on Soil. ProfessorStephen A. Boyd, Michigan StateUniversityM,ay 19, 1993.
OTHER Last changed: 5/17/00
Attachedarecomments on the3M TechnicalReport "Adsorptionof FM-3925 on Sofl.S.K. Welsh and C.H. Schrandt,Project9970612631 Fateof FluorochemicalsR,eport No. 13,Mar. 22, 1979" made by ProfessorStephenA. Boyd, Mchigan StateUniversityd,atedMay 19, 1993.
Review of TechnicalReportSummary Adsorptionof FM 3925 on Soil
Materialsand Methods
I would not recommend oven dryingsoils.Use airdriedsoilsand do a separatemoisture determinatio(noven drying)to getthe moisturecontent.
Solubilitwyas determinedearliears 2.3 ppm.
Desorptionexperimentsshouldprobablyuse diluteCaCI2 solutionisnsteadof deionizedwater which willcause the soiltodisperse.
The extractionproceduredescribedutilizinegthylacetateneeds validation.The percent recoveriesof FM 3925 from standardsolutionshouldbe reported.
The sorptionisothermonly extendstoan equilibriucmoncentratioonf about0.22 ppm which is10 timeslower thanthewater solubili(tSy,)ofFM 3925. The isothermneedstobe extended to 0.5 S,,o,r greater,i.e.,equilibriumaqueousconcentrationaspproachingS,,,T.his istheonly way to establisthhelinearitoyf the isotherm.I'm againnot certainof the meaning of the desorptionexperiments.Iwould notdraw any major conclusionrsegardingmobilityfrom those data.
There isabsolutelnyo evidenceforelectrostatfiocrcesbeinginvolvedin soilbindingof FM 3925. This ispure conjectureand almostcertainlwyrong. The onlyelectrostatmiecchanism would be toprotonatetheN of FM 3925 to createa cationicspeciesthatcould interacwtith negativelcyhargedsitesin soilclaysand soilorganicmatter.The pKa of FM 3925 would indicatethelikelihooodf that.The linearisotherms(iftheyare infactlinear)sug@gesstolute partitioninogtadsorptiobny electrostatfiocrces.SolutepartitioniinngvolvesdissolutioonfFM 3925 inamorphous soilorganicmatter.The magnitudeofthesorptioncoefficien(tK,.)depends on therelativseolubilitoyfFM 3925 in soilorganicmatterand water.The K, valuesreported forFM 3925 is3500 (100K/% organiccarbon = 100 x 330/2.2).The K valuereportedwas 77 so itshouldbe: K.. = 100 x 77/2.2= 3500. This may be a reasonablvealuealthoughit would be easiertoevaluateiftheK,,,w.as known. Gareen and Kaiickhoff(1990,Pesticideisn the SoilEnvironment,Chapter4, SorptionEstimatesforModeling,SoilScienceSocietyof America, Madison, WI) givetheempiricaelquation:
Log K. = -0.68log S (,gg/mlx)4.273
which usingthe solubilitoyf 2.3 yieldsa predictedK, of about 10,000so itsatleastclose. Equationslikethisusingsolubilitioefssolidsthathaven'tbeen correctedformeltingpoint,i.e., convertedtosupercooledliquidsolubilitigeisv,eprettyrough estimates.I thinkyou couldget a betterestimateifyou knew K.,,.
Recommendations
1. Measure the octanol water partitioncoefficient,relate measured S to Y%,,.via Chiou's equation:
logK,,.= -0.862log S,,+, 0.710
remembering S, of a solidshouldbe convertedto supercooledliquidsolubilitiyfthe meltingpointismuch over 100*C.
2. Extend range of equilibriumaqueousconcentrationtso approach& in the sorption isothermexperiments.Test othersoilstoevaluate
3. Determine thepKa of FM 3925 toevaluatelikelihooodf electrostatiincteractions.
amm Form6747.11-A
TECHNICAL REPORT SUMMARY
Date
3/22/79
TO:TECHNICAL COMMUNICATIONS CENTER - 201-2CN (importa-ntIfreporitsprintoendbothsideosfpapers,endtwocopietsoTCC.)
Division Project
Environmental Laboratory (EE & PC)
Fate of Fluorochemicals
Report Title
Adsorption of FM-3925 on Soil
To
A. N. Welter
Author(s)
--
-,:-@,Y-tL)
11 Stephen K. Wels@)& C. H. Schrandt
Notebook-BeferenoL------
#51050
SECURITY III-
F-I Open (Company Conf iden tial)
'LI. Closed (Special Authorization)
KEYWORDS: (Selectterms from 3M Thesaurus. Suggest other applicableterms.)
EE & PC Fluorochemical
CURRENT OBJECTIVE:
To obtain an indication
3M CHEMICAL REGISTRY
of FM-3925 mobility
-Dept Number
0535
Project N umber
9970612631
We-p-or-t-gum-b*r
013
-Employee Number(s)
073583, 113152
No. of Pages Includina Covershost
11
New Chemicals Reported
Yes
[3a No
in a sandy loam soil.
REPORT ABSTRACT: (200-250vvordsT)hisabstracitnformatioinsdistributbeyd thetechnicaClommunicationsCenterto aler3tM'ersto Company R&D. ItisCompany confidentimaalterial.
To obtain an indication of mobility of FM-3925 in a sandy loam soil, adsorption/desorption experiment.s similar to those of Davidson, 1976, and of Ha-make-r,1975, were; conducted. FM-3925 was judged to be immobile based on an adsorption coefficient of 77; leis.than 15% desorption with three desorption extractions; and water solubility of only 2.16 mg/l.
Information Liaison
initials: 15
FM-3925;
-2-
3/22/79
CONCLUSIONS
The adsorption coefficient for FM-3925 was 77. Considering the adsorption coefficient, desorption characteristics, and water solubility, FM-3925 would be judged immobile in the sandy loam soil used in this study.
INTRODUCTION
As a part of the Fate of Fluorochemicals Project, an indication of mobility of FM-3925 in sandy loam soil was desired. Adsorption-desorption experiments (after Davidson, 1976 and Hamaker, 1975) along with water solubility data can provide this indication of mobility. This approach is used by the USEPA in pesticide registration requirements.
MATERIALS AND METHODS
Duplicate 5-g samples of oven-dried (1030 C.) Brill sandy loam soil (57% sand, .36% silt, and 7% clay, with 2.5% organic matter, 2..2%organic carbon, with @H 6.5 and CtC -of-15.3 meg/100 g) were shaken with 40 ml of solution in 50 ml glass centrif0uge tubes for 24 hours on a wrist-action shaker at room temperature (16-19 C.). Glass tubes were used because it was believed, based on prior experience, that glass would adsorb less FM-3925 than polypropylene or polyethylene tubes.
Solutions were made by diluting a stock solution of the chemical. The stock solution was the 24-hour sample from the second Vieth study of water solubility (46269-53 and 48277"8). Concentrations of FM-3925 were 2.16 mg/l, 1.21 mg/l, 0.691 mg/l, 0.389 mg/l, 0.216 mg/l, and 0.022 mg/l (100%, 56%, 32%, 18%, 10%, and 1% of stock).
After shaking:-theinitial solutions, as well as the three desorption extractions with deionized water, the samples were centrifuged at 3000 rpm for 30 minutes, and each supernatant solution was decanted off into glass *sample vials.
After removing the 40 ml of initial solution for analysis, 40 ml of DI water was put into the tubes for the first desorption extraction. Similarly, the second and third desorption extractions were conducted.
The samples, now in glass sample vials, were analyzed by first adding 5 ml. of Burdick and Jackson distilled in glass ethyl acetate to each vial, mixing on a Genie Vortex Mixer at maximum speed for 30 seconds, and centrifuging at 2500 rpm for 10 minutes. The ethyl acetate layer (about 1 ml) was then drawn off with a transfer pipet to a clean vial and then two more extractions were conducted with 2 ml of ethyl acetate each followed by mixing and centrifuging as above, and the ethyl acetate layers from each successive extraction were combined in the same clean vial. Then, 15 ml of ethyl acetate was added, and the extracts were evaporated to near dryness under nitrogen and then transferred to 4-ml concentrator tubes and brought up to 1 ml with ethyl acetate. After transferring to automatic sampler vials, gas chromatograms were run on duplicate 5-jilinjections of the extracts. GC equipment and conditions included:
FM-3925
-3-
3/22/79
Colum - 61 x 1/811O.D. stainless steel, 10% Carbowax 20M on 60/80 mesh
Chromasor0b W-AW; Chromatogr0aph"HP 5713, Ni 63 Detector; Conditions - Inject
Port 200 0
C., Detector 300
C.
Flow 35 cc4min. Ar/CH
95/5, Oven temp.
175 for 16 min., then up to 2;00 C. at 32 /min. for i min.
Statistical analysis and plotting of the data was done with the MINITAB package of the 3M TRAC computer service.
RESULTS AND DISCUSSION
Adsorption data for FM-3925 are given in TABLE I. The amount of FM-3925 removed from solution by the soil (Column C) was 83-90% of the initial amount at the various starting (initial)concentrations.
Equilibrium concentrations in solution (C) in mg/l are shown in Column B, and amounts adsorbed on the soil (x/m) in jigFM-3925 per gram soil are shown in Column F. The regression equation of the adsorption isotherm shown in FIGURE 1 was x/m = -1.7 + 77C, so'that the adsorption coefficient, K, was 77. The linear shape of the adsorption isotherm indicated that FM-@3925adsorption on soil would be independent of concentration in solution. The high percentage adsorbed and the relatively high adsorption coefficient indicated that FM-3925 would be immobile in this sandy loam soil.
Desorption data are given in TABLE II,and the desorption isotherms are shown in FIGURE 1. Of the amounts initially adsorbed on the soil, less than 15% was removed by the three desorption extractions with water (TABLE II, Column I). This small amount of desorption is also shown by the -fairlyhorizontal slopes of the desorption isotherms compared with the slope of the adsorption isotherm. This very small amount of desorption was another indication of the immobility of FM-3925.
The large amount adsorbed and the small amount desorbed suggests strong binding of FM-3925 to soil particles by intermolecular interactions involving electrostatic forces.
The adsorption coefficient based on soil organic carbon, K , fbr FM-392S would oc
be 3,500 (100 K/% organic carbon = lOOx330/2.2). Compared with K values for a selected group of pesticides and other fluorochemicals (TABLE 1?1), 3,500 is quite high and is another indication of low mobility of FM-3925.
These adsorption and desorption data, along with the low water solubility o f FM-3925 (2.16 mg/1), provide good evidence that FM-3925 would have very low mobility in the sandy loam soil used in this study.
In a @lcontrol"using the full-strength stork solution and.no soil, it was found that 53% of the FM-3925 was -r6moved'frord@olution (100 x (2.1-6-1.007)/2.16), being adsorbed on the glass tubes (TABLE IV) . Of the amount'adso-rbed,20% (100 x (46.1-37.1)/46.1)was subsequently desorbed in three desorption extractions with DI water (the desorption isotherm is shown in FIGURE 2).
FM-3925
-4-
3/22/79
This control experiment indicated that a considerable portion of the FM-3925 removed from solution (TABLE I, Column C) was being adsorbed on the glass
rather than on the soil. In order to correct for this in the calculations, it would be necessary to conduct such controls at each of the initial concentrations. While such a correction would make it truly a "soil adsorption" experiment, it probably wouldn't change the conclusions. The % removed "by soil" would be lower, and the amounts on the soil (TABLE I, Column F) would be lower moving the adsorption isotherm down, but the adsorption coefficient (the slope of the isotherm) may not change. Likewise, the desorption isotherms may be shifted down without changing the desorption coefficients. Also, since there is no carbon in the glass, the adsorption coefficient based on organic carbon content of the soil, Koc' should remain the same.
TERMS
c
- Concentration of chemical in solution at equilibrium
X/M
- Concentration of chemical adsorbed on soil at equilibrium
2
R
- Coefficient of determination
K
- Adsorption coefficient
Koc - Adsorption coefficient based on soil organic carbon content
REFERENCES
Davidson, J. M., et al, 1975, Use of Soil Parameters for Describing Pesticide Movement Through Soils, USEPA, EPA-660-2/75-009.
Davidson, J. M., 1976, "Vertical Movement and Distribution of Organics in Soils," Presented at Symposium on Nonbiological Transport and Transformation of Pollutants on Land and Water, at National Bureau of Standards, Gaithersburg, MD, May 11-13, 1976.
Hamaker, J. W., 1975, "Interpretation of Soil Leaching Experiments," in glemicals, Human Health and the Environment, A Collection of Dow Scientific Papers Vol. 1, Dow Chemical USA, Midland, MI 48640.
Hamaker, J. W. and J. M. Thompson, 1972. "Adsorption" in Organic Chemicals in the Soil Environment. C. A. I. Goring and J. W. HaEker 7ed!@.) Marcel Dekker, Inc., NY.
SKW/CHS/cen
TABLE I .FM-3925 ADSORPTION
DATA
A Initial FM 3925
Conc., mg/l
2.160 (100%) 1.210 (56%) 0.691 (32%) 0.389 (18%) 0.216 (10%) 0.022 (1%)
B Equil. Conc.,
C, mg/l
0.2135 + 0.0516 0.1455 + 0.0106 0.0940 + 0.0156 0.0490 + 0.0042 0.0370 + 0.0028
c Removed by Soil & Glass Tubes A-B
x 100 A
90
88
86
87
83
D Total FM 3925 In Initial Solln, mg (A x 0.04 liters)
0.0864
0.0484
0.0276
0.0156
0.0086
E Total FM 3925 In Solln at Equil., mg (B x 0.04 liters)
0.00854
0.00582
0.00376
0.00196
0.00148
F FM 3925 Adsorbed on Soil, XVM,Ilg/g (D-E ldisgi.
15.57
8.52
4.78
2.72
1.43
*All samples at the 1% initial concentration were below the detectable limit and these were not included in the calculations.
TABLE II FM-3925 DESORPTION ISOlliERM DATA
A Equil. Conc. in
Solution, C, mg/l
(Table 1, Column B)
0.2135 + 0.0516 0.1455 + 0.0106 0.0940 + 0.0156 0.0490 + 0.0042 0.0370 + 0.0028
B Equil. Conc. in First Desorption
mg/l
0.1160 + 0.0057 0.0585 + 0.0035 0.0310 + 0.0057 0.0165 + 0.0007 0.0050 + 0.0057
c Equil. Conc. in Second Desorption
mg/i
0.0605 + 0.0021 0.0410 0.0130 + 0.0028 0.0100 0.0010 + 0.0
D Equil. Conc. in Third Desorption
mg/l
0.0525 + 0.0134 0.0260 0.0080 + 0.0099 0.0080 + 0.0 0.0035 + 0.0035
E Amount Adsorbed
on Soil, x/m lig/g (Table 1, Column F)
15.57 8.52 4.78 2.72 1.43
F Amount on Soil
After First Desorption, ug/g
14.64 8.05 4.53 2. 59 1.39
G Amount on Soil
After Second Desoation, lig/g
14'.16 7.72 4.43 2.51 1.38
H Amount on Soil
After Third Desorption, pg/g
13.74 7.S2 4.36 2.44 1.35
I
Percent Desorbed
(E-H)
E
100
12 12 9 10 5
TABLE III
COMPARISON OF ADSORPTION COEFFICIENTS FOR A SELECTED GROUP OF PESTICIDES (Hamaker and Thompson, 1972)
Chemical
K
oc
(mobile) (immobile)
Chloramben (FC-143 - - - - - - - - - - - -
12.8 17)
2,4-D
32
(FC-95 - - - - - - - - - - - - - 45)
Propham
51
Bromacil
71
Monuron
83
Simazine
135
Propazine
152
Dichlobenil
164
Atrazine
172
Chloropropham
245
Prometone
300
Ametr)rn
380
Diuron
485
Promet-ryne
513
(FM 3925 - - - - - - - - - - 3,500)
Chloroxuron
4,986
(FM 3422 - - --- - - - - - - 15,0001
Paraquat
2.0,000
DDT
243,000
14.0+ 12. 0+ 10. 0+
13.4 + 10 C R' 0.950
x/m 2
R
-1.7 + 77 C 0.972
0
8.0+
B B---
bo
x/m = 7.4 + 7.9 C
6.0+
2= R 0.886
0 4.0+
0
c x/m 4.4 + 4.6,C
2 R 0.968
- DW 2.0+
x/m 2.4 + 5.9 c
2= R 0.838
x/m = 1.4 + 1.6 C
R2 0.635
0.0+
---------------------------------------------------
0.0(10
0.060
0.120
0.240
0.30'0
Equilibrium Concentration in Water Phase, C, mg/l
FIGURE I FM-3925 ADSORPTION AND DESORPTION
ISOTHERMS
--@PLAT
C41 C42
C41 46.0+
44.0+
to
40.0+
(D 0
38.0+
x/m 38.2 + 8.OC R2 0.885
36.0+
----------------------------------------------C-4-2---
0.40
0.80
0.20
0.60
1.00
Equilibrium Concentration in Solution,.C,mg/l
FIGURE 2
FM-3925 DESORPTION FROM GLASS TUBE
------------------- --- --------------
TABLE IVFM-3925 DESORPTION FROM GLASS TUBE DATA
Initial First Desorption Second Desorption Third Desorption
Equilibrium Conc. in Solution, C, mg/l
1.007 0.141 0.043 0.042
Amount Remaining on Tube, x/m,-pgLTe
46.1 40.5
38.8 27.1
APPENDIX I
RAW FM-3925 SOIL ADSORPTION (pg/l)
DATA
Initial FM-3422 Conc., lig/l
Equil. Conc., C, @g/l A & B are Duplicate Samples, Duplicate--Injectionsinto GC
2160 (100%) 1210 (56%) 691 (32%)
389 (18%) 216 (10%
21.6 (1%)
A
176,177 136,140 104,105 52,52
39,38 <5
B
250 154,151 85,80 46,45
35,34 <5
Equil. Conc. in First Desorption A & B are Duplicate Samples, DAMlicate Injections into GC
A
B
120,119 56,56 28,25 16,16 <5,<S
<5
112,112 62,59 35,3S 16,17
9,9 <5
Equil. Conc. in Second Desorption A & B are Duplicate Samples) Duplicate Injections into GC
A
B
59,59 42,40
11 10,9
<5 @<5
62,62 15
<5,<S <5
Equil. Conc. in Third Desorption A & B are Duplicate Sanplesp Duplicate Injections into GC
A
B
60,63 26,26 <5,<S
8,8 6,6 <5
44,42 -
15,15 8,8 <5,<S <5
Control
Control
A
B
Initial lst2nd 3rd
815,872 185,191
86,84 82
1140,1200 96,94 <5,<S <5,<S
APPENDIX II
AVERAGES OF DUPLICATE INJECTIONS -FROM APPENDIX I
Equil. Conc. ug/l
A
B
177
250
138
153
105
83
52
46
39
35
First Desorption
A
B
120
112
56
61
27
35
16
17
<5
9
Second Desorption
A
B
59
62
41
-
11
10
<5
<5
Third Desorption
A
B
62
43
26
-
<5
is
8
8
6
<5
Initial First Desorption Second Desorption Third Desorption
Control
A
B
844 Ug/l 188 85 82
1170 ug/i
95 <5 <5
Mean + S.D.
1007 + 231 141.5-+ 65.8
43 +-59.4 41.5-+ 57.3