Document 2qKZGxO00zorxnd0aEyXMyopg

AR226-048Y SOIL ADSORPTION TEsTsuesTANcE Identity: Perfluorooctanoic acid, ammonium salt; may also be referred to as PFOA ammonium salt, Ammonium perfluorooctanoate, PFO, FC-116, FC-126, FC-169, or FC-143. (Octanoic acid, pentadecafluoro-, ammonium salt, CAS# 3825-26-1) Remarks: The test sample is FC-143. It's purity was not sufficiently characterized, though current information indicates itis a mixture of 96.5 100% test substance and 0 -- 3.5% Cs, Cy, andCsperluoro analogue bceoimnpgournepdesa.teTdhpeertecsutrsruenbtstparnocceeduusreeds waansd 'b`eCs-tlaabvealielda.bleThpirsactteiscteisn.g is METHOD: Method: ~~ Adsorption-Desorption study using the approach recommended by the U.S. EPA for pesticide registration GLP (VN): No SYteaatris(tsictauldymeptehrofodrsm:ed): S1t9a7ti8stical analysis and plotting of the data was done with the MINITAB package of the 3 TRAC computer service. Temperature: ~~ 16-19C Stock and test solution preparation: Test solutions were made by `dTilhuetitnygpea osftoscoklvseonltutuisoendofto"Cm-alkaebetlheedsatomcmkosnoiluutmiopneirsfnloutornoootcetda,nonaotre.is the activity of the "C-labeled test substance. Remarks field: The Brill sandy loam soil was characterized as having 57% sand, 36% silt, 7% clay, 2.5% organic matter, 1.5% organic carbon, with pH 6.5 and cation exchange capacity of 15.3 meq,/100 gms. wSattaenrdaartdcosnolcuetnitornastioofntsheof"5C2-3lambge/lLe,d 2c9o3mpmgo/uLn,d1w6e7rmegp/rLe,p9a4remdg/inL,D..5I.2 mg/L, and 5.2 mg/L. Twenty-five ml of each solution was shaken with duplicate 5 gram samples of the soil in a 50 ml polypropylene centrifuge tubes for 24 hours on a wrist shaker at room temperature (16-19C). Desorption extraction were performed with D.1. water after the adsorption phase of the experiment. The samples from the adsorption and dmeisnourtpetsi,oanfteexrpwehriicmhe,nttshrweeeraelicqeunottrsioffugeeadcihndsiuvpideumaalltyaantt5s0ol0u0tiropnmwfeorre10 prepared for scintillation counting. From the raw counting data, compound concentrations were calculated for all of the supernatant solutions. 03614 RESULTS Ki 021 (N=1) Ko: 14 * The study report had indicated a K of 0.38. This is the coefficient of C in the regression equation, not the adsorption coefficient value, based on best fit. Taking a mean value for K based on K=(/m)/Cq, K = 0.21. The Ky value based on the initially reported organic carbon content of 1.5% and the mean value for K (Ke: = K x 100/1.5(% organic carbon) becomes 14. CONCLUSIONS The study substance is expected to exhibit high mobility in the kind of soil tested. Submitter: 3M Company, Environmental Laboratory, P.O. Box 33331, St. Paul, Minnesota, 55133 DATA QUALITY Reliability: Kiimisch ranking 3. This study lacks detail on the stock saonlaultyisoins aonfdthtehesopilurtiotyveorfiftyheth"eC-almaobuenltedretmesatinsiunbgstfaonrcme.assThbearleanwcaes. no Discrepancies in the organic carbon content are present. Use of DI water instead of CaCl. Additionally, some calculations have questionable reliability. Additional comments by Professor Stephen A. Boyd, Michigan State University, also indicate the reliability level of this study. REFERENCES 3M Technical Report "Adsorption of FC 95 and FC 143 on Soil." SK. Welsh, Project 9970612633 Fate of Fluorochemicals, Report No. 1, Feb. 27,1978 3M requested expert review by Professor Stephen A. Boyd, Michigan State University, May 19, 1993. OTHER Last changed: 5/25/00 G03615 Co " Attachedare commeonntthse 3MTechnical Report *Adsorption of FC 95 and FC 143 on Soil. SK. Welsh, Project 9970612633 FateofFluorochemicals, Report No. 1, Feb. 27, 1978" made by Professor Stephen A. Boyd, Michigan State University, dated May 19, 1993. 03616 Review of Technical Report Summary Adsorption of FC 95 and FC 143 in Soil Material and Methods Ssohrobusldlegsisvtehraencgolvaesrsieosnofpocloymetphoyulnendes,ibnubtldaoneksn('not-sgoiivle) aexnpuemreirmiecnatls.vaSltuaet.es that polypropylene `voTlhaetillairzgaetihoenadosrpascteic(k2in5g mi to in a the 50 tube) is tube, will undesirable; inflate the saonryptlioosnsecsoeofffitchieen"tC-slianbceel,thee.g.m,eftrhoomd `ccaolnccuelnattreastitohnes.amAolusnot tshoer2b4edhobuyrdmiifxfeirnegncpeerbieotdweseenemtshearibniittriaarly.andWefrinealeexqpueirliimbernitusm dsoonleutifoonr different periods of time to establish that equilibrium was reached within 24 hours? Details activity oanndtrhaedisotocchkemsioclaultipounriatryeoflatchkeinCg.-FWCha9t5. solvent was used and what is the specific `sToihle aisdewaeollf uassiwnagtaerc.ottTohnesw~a2b0a%fteorrtlheessdrdaeicnrienagsestienp sisoluuntuesucaoln.cenHtorpaetfiuolnldyutehitsodsiodrnp'ttiroenmiosnv'et as high as I'd like to see it. A 50% or greater decrease would be better. `This section generally lacks detail that would normally be required for publication. Results and Discussion `dTehmeonlsinteraartietytohafttthheeiesnottihreermishoathsebremeins slihnoewarn, otvheerlitnheearciotnycemnutsrtateixotnenrdantgoeeuqsueidl.ibrHiouwmesvoelru,tiotno `concentrations that approach the water solubility of the compound. Do you know the solubility of FC95 or FC143: If not, how were the initial solution concentrations selected? `The sorption coefficient (K) of normalized sorption coefficient FC 95 (Ke, = appears to be K/f,g) is Keg about 1 as = 1/0.025 indicated. = 40, or The organic matter og K,,, = 1.6. This tisoaexsoaimlisnoerpstoiomnecaodedfifitciioennatl isnotielsrmteodicaotnefbiermtwteheisn bKe,n.zveanleuea.ndGteonleureanlel,y,IttwhoeuKl.,d,bvealwuoersthswhhoiulled: converge within a factor of 2 to 3 for different soils. This would increase my confidence in the accuracyofthe one measured value. I've spot checked the soil concentrations of FC-95 for both the sorption and desorption experiments and I get essentially the same values. The calculations look good. The K values for FC 143 is lower than FC 95 indicating that it probably has a higher water `sTolhuebisloirtpyt.ioTnhiesohytshteerrmsiiss ilnintehaerdiensdoircpattiionng iasositnhgelrem siosrsputripvreispirnogc,esasn.d hTahsebceoennclovuesri-oinntreergparredtiendg. "three different binding mechanisms .. with stronger binding at higher concentrations and the converse at lower concentrations" is very speculative based on the single experiment. If one. examines column I "Amount Desorbed as a Percent of Amount Adsorbed" the values. range from . 03617 26 10 212 percent, 1. Environ. Qual. s1o2:i3t'2s5p-r3e3t0tybiyncKoonsclkuisnievne.anTdheCrheenisgawfhaiorloybgsoeordveddistchuissspiohnenoofmheysntaerfeosristhien iwnecalkudaecmiidcrpeosbtiiacliddeeg2r,a4d,a5t-iTo.n oTfhteheccauosmepsouofndhydsutreirensgisdesaorreptviaorni,edanadndchcaonmgpelsiciantetdheapnhdysimcaayl wanadt/eorr(cahseimsictahle pcraospeerhteirees) ocfouthled sroeislu-lstoliuntisoonilsydsitsepme.rsiFoonrseoxathmaptlea,cdleeasrorsputipoenmautsainntg dsiosltuitliloedn `could not be obtained. This can cause quenching of radioactivity in solution and other problems leading to error. b`Tahlean"cmeatyeoruiaslhobualldanmcee"asausreprtehseenatmeodunint othfe"rCe-paocrttiviistya ilnitstoleilmaitsltehaedienngd.ofTtoheobetxapienriamemnatt,erainadl add it to the measured solution concentrations. General `whereas tChoemmvaelnutes.statTedheinKt,h,e vMaaltueersiaclaslcaunldateMdethheordesuisse 1a.n5%o?rganic carbon content of 2.2% `The water solubilities latter value is wrong. are If cited as 300 mg/L the solubilities are for FC 95 truly that and > 20g/L for FC 143. different, then the sorptive Surely the properties tshheonulId wboeulvdasetlxypedcitffneroensto,rpwthioinc.h they This avraeluneotm.usItf bFeC1er4r3onheaosusa. solubility of >20,000 mg/L, `Recommendations: 1. Obtaining K, K., values on additional soils. Determine if Ko, is relatively constant. 2. Obtain a true mass balance by measuring "C-activity in soil and solution phase. 3. Interpret desorption data more cautiously. . 4. Get correct value of water solubility of FC 143. 03618 A TECHNICAL REPORT SUMMARY TO: TECHNICAL COMMUNICATIONS CENTER 201.208 (important - Hfapso pinteodn both idofepapser en wo copie0 TCC.) 2/21/78 or FEaEte6 oPCf Fluorochemicals Adsorption of FC 95 and FC 143 on soil r0o2e22 9970612633 1 0 on 3 sr Stephen K. wesn SW re 73583 Pr re Ca [---- #40673, #47704 Goer FETT Eam14 on e[ vwone os: e ese ae ConENT ORECTIVE: . To obtain an indication of FC 95 5 and FC 143 mobility in sandy loam soil. EE 4 BC - Div. Fluorochenical Soil Adsorption Mobility EFT+AaBsSeTRACT. G20rd50ers Tirseose rmforamatnions Geeraddooy oeoeTTeaeaComoo=Gor As oa rpart of the Fate of Fluorochemica.ls Project, an indication of mobility of FC 95 and FC 143 in sandy loam soil wasdesired. Adsorption-desorption experiments (after Davidsovn, 1976, and Hamaker; 1975) along with water solubility data can provide such information. The adsorption coeffints for FC 95 and FC 143 were determined to be 0.99 and 0.38, respectively. For FC 95 adsorption and desorption could be described by a'single valued function while for FC 143, they could not. Based on these data, both compounds would be judged mobile in the sandy loam soil used in this study. inemin Lin . 03619 .. 2 concustons Adsorption coefficient for FC 95 and FC 143 were 0.99 and 0.38, respectively. For FC 95, adsorption and desorption could be described by a single valued function while for FC 143, they could not, Considering adsorption coefficients, desorption characteristics and water solubilities, both compounds would be judged mobile in the sandy loam soil used in this study. INTRODUCTION AS a part of the Fate of Fluorochemicals Project, an indication of mobility of FC 95 and FC 163 in sandy loam soil vas dered. Adsorptiondesorption experiments (after Davidson, 1976, and Hamaker, 1975) along with water solubility data can provide this indication of mobility. This approach is used by the U. S. EPA in pesticide registration requirements. MATERIALS AND METHODS Duplicate S-g samples of air-dried Brill sandy loam soil (57% sand, 36% silt, 7% clay, 2.5% organic matter, 1.5% organic carbon, with pH 6.5 and C.E.C. of 15.3 meq./100g) were shaken with 25 ml of solution in 50 ml. polyPropylene centrifuge tubes for 24 hours on a wrist action shaker at room temp. (16-15%). Polypropylene tubes were used because they were found in separate experiments (3M Tech Notebook #470673, C. H. Schrandt) to absorb less FC 95 and FC 143 than glass or polyethylene tubes. Solutions were made by diluting a stock solution of each chemical. Concentrations of C-labeled FC 95 were 282 mg/1., 158 ng/1., 90 mg/1., S1mg/l., 28 mg/1., (100%, Ses, 32%, 18%, 108, 1% of stock). Concentrations of MC labeled FC 145 vere 525 mg/1., 295 mg/l. 167 ng/L, 94 mg/l. 52 mg/1., and 5.2 mg/1. 03620 : 3 After shaking the initial solutions as well as the three desorption extractions with deionized water, the samples Were centrifuged at 5000 rpm for 10 min., and three aliquots of each supernatant solution Were taken for scintillation comting. After the adsorption step, 22.5 ml of solution were recovered. Therefore, it was assumed that 2.5 ml of liquid remained with the soil in each step and this amount was accounted for in the desorption' calculations (see Results and Discussion section). In the FC 95 experinent, the supematant liquid was simply drained In the FC 143 experiment, the supernatant liquid remaining after the draining step was absorbed with a cotton swab before putting the next 25 al of liquid into the tubes. The procedures for the FC 95 and FC 143 experiments were recorded in 3M Technical Notebook #40673, p. 49 and p. 51, respectively. From the rav counting data, disintegrations per minute (OPMj and FC 95 and FC 143 concentrations were calculated for all of the supernatant solutions. Statistical analysis and plotting of the data was done with the MINITAB package of the 3M TRAC computer service. RESULTS AND DISCUSSION Fc 95 Adsorption data for FC 95 are presented in TABLE I and FIGURE 1. Comparing the regression equation of the adsorption isothern (FIGURE 1) X/m = -0.29 + 0.99 with the Freundlich equation x/m = KN, it could be esqeueanletdhatonet.he Tahdesorlpitnieoanr schoaepfeficoifentth,e aK,dsoerqputailoend 0i.s9o9thearnmds th(eNe1e)xpoinnednitc,ateN,d 0362 . 4 that FC 95 adsorption on soil would be independent of concentration. The low adsorption coefficient (K=0.99) indicated that FC 95 would be mobile, soll. di.e., it would move readily with the ground water through this sandy loam TABLE 1 A Initial FC 95 Conc., ng/L ---- 281528.120 0si..00 282080 D In TIontiatlialFCSo9l5'n (Ax 0.025 liters) 7.0500 3.9500 012...272705500000 0.0700 FC 95 ADSORPTION DATA 5 Equil. cone, C, m/l. --l. 2133430.29 7462.90 222..01 E SoTiontalatFCEqu9i5l.i,n mg (Bx 0.025 liters) 5.84750 3.35500 01..105.9552022055000 0.05000 c + Removed to x7 1175.111 1174.086 2217010 wel FY onFCSo9i5l,Adsxonr,bedug/g (D-E) x W10 wvp/em 240.8 119.0 4260550.357 38 Desorption data for FC 95 are shown in TABLE II and FIGURE 2. For comparison, desorption isotherns for the pesticide fluometuron are given in FIGURE 3. For clarity FC 95 desorption isotherms are not drawn in FIGURE 2. However, all of the data points lie very close to the adsorption isotherms indicating that adsorption and desorption could be described by a single-valued function with desorption coefficients, K', equaling the adsorption coefficient, [3 03622 Le 5 240 s a . 180 3 8 120 38 % 2 60 . a A B A RegresRs-iSoqnuarEeqnd.:= 0.98=5-0.29 + 0.99 X A = Actual Data Points B = Predicted Y Values 0 o 0 60 120 180 20 300 Equil. Conc., C, mg/1 FIGURE 1 FC 95 Adsorption Isothern This, along with the observation that approximately all of the adsorbed FC 95 was subsequently desorbed (TABLE II, Column H) indicated that binding forces were weak and would be another indication of high mobility of FC 95. Material balance data for FC. 95 are presented in TABLE III and these data indicate that all of the chemical was accounted for throughout the experiment. 03623 Lo 6 . A EqSuoillu.tioCno,nc.C, in mg/l. 213334..920000 4726..090000 22.2.010000 THBLE FC 95 DESORPTION 5 FiErqsutilD.esCoornpct.ionin mg/l. 5520..73000000 198..63000000 0.5.63000000 11 ISOTHERM DATA c SecEoqunidl.DesCoonrcp.tioinn mg/l. 194..09000000 25..53000000 01..27000000 ThiErqduilD.esCoornpct.ionin mg/l. 52..2300000000 11..3000000000 00..1600000000 E F [a 1 Amount.onASdosiolr,bed AAfmtoeurnt FoinrstSoil AAmfotuenrtSe`ocnoSndoi AmoAufntetronThiSroidl x/m ug/g Desorption, ug/g Desorption, ug/g Desorption, ug/g (Col21u61mn09..F80,0000TABLE I) 6179..64050000 -1412..50000000 -2-59..81050000 15615.370000 29.500 31.3.32000000 11.4000 "21.6.07500000 4.7000 "2"32..90500000 2.2500 pr 1.7000 029000 0.4500 *wCFiortolhmumnctshoerrF,percetG,viioonaunsdfoHrstewtpehreeinamcoeaualnccthuloacftaesdeFCi(n9S5eethiMenattsehareniea2l.ws5ayBalnadsoMCfeotlshuoomldnustiF,oSnecTtrAieBomLnEa.i)n1ing el : i + Misomption sorter : 1rc 3I 8 A i LF oF teann c EE FIGURE: 2 FC 95 DAEDSSOORRPPTTIIOONN.DA1TSAOTPHOEIRNMTS pH ur somow ne Gwopant 3 Flue 3"TM c03624 AFDLSUOORMPETTIUORNOHAONND CDEOSBOBRPSTANIDO.N ISSOOLTHIEDRMASNDFOBRROKEN LINES ARE BEST FIT FOR A A ADSORPTION AND = Lo 7 TABLE TIX FC 95 Material Balance* Total AInitial' (FCCol9u5mniDn;STolAuBtLiEonI,) mg. 73..0955000000 21..2257050000 00..07700000: FC 95 in8Solution (CatoluEmqunilE.,,"TmAgB.LE I) 35..3854570500 11..909520500 00..5055205000 FC 95 con soil at Equil., ng. G-B) 01..5290520500 00..232257050 0.14750 0.02000 FAimrosutntDeRseDomropvteidonb,y mg. 00..489674755000 00..311519000000 00..009101550000 Total G Amount DDeessoorrpbteidonbsy, Tnhgree DIE) 10..27428403 00..24345703 00..10316738 E SeAcmoonudntDesRoermpotvieodn,byng.. 00..217781070500 00..015050705000 00..003034500000 Amount RemHaining on tSoiiolns,Afmtge.r 3 (CDes-or6)p- <P ATmhoiurndtDeRseomropvteidonb,y ng. 00..100554755000 00..003260225500 00..001022225500 Amount 1Desorbed as P(e6r/cCenxt1o0f0),Amount Adsorbed --00..4152795000 -0-0..0111090750 00..01012225500 112013..688015 113064..544645 8982..735703 O"fColFuCm-n9s5 Di,n 2E,7.a5nmdlF (w2e5remlobatdadiendedplubsy 2fi.r5stml carlecmualiantiinngg frtohme amount (ng) previous step) oifn sthoelu2t.i5onmlinofeacsholruteisopnectrievmeainsitnegp afnrdomthtehne psruebvtiroaucstinsgtept.he amount (ng) 03625 oe 8 FC 143 Data for FC 143 are presented in TABLE IV and TABLE V and in FIGURE 4. The adsorption isotherm indicated FC 143 mobility similar to that of FC 95 with K=0.38 and Nl. Regression analyses were not performed on the desorption isotherns, however, the graphed data (FIGURE 4) indicated that adsorption and desorption could not be described by a single-valued function. That is, the K' and N' values for desorption would not be the same as K and N for adsorption. Subjective evaluation would indicate that the desorption coefficient K', would be much smaller than the adsorption coefficient, K, at solution concentrations greater than about 25 mg/l, since the slope of the adsorption this range. At solution concentrations less than 25 mg/l., the desorption coefficients would appear to be much greater than the adsorption coefficient. From this it would appear that two or three different binding mechanisms were involved with stronger binding occuring at the higher concentrations and the converse at lower concentrations. While this may indicate a tendency for FC 143 to be immobile at high concentrations, it would be quite mobile in any situations involving low concentrations. : Material balance data for FC 143 are presented in TABLE VI. While the two concentrations resulting in 212%and 201% desorption (last column in TABLE VI) were erratic, in general, the data indicated that all of the FC 143 was accounted for throughout the experiment. 03626 .o. TABLE IV : FC 143 Adsorption Data A Initial C143 Cone,. mg/l. 255222..65 1697..12 52.3 5.2 5 Equil. Conc, Cc, mg/l. . 247895..18 19620..23 4919 5.1 c 2 Removed By Soil [4 re x 100) SV7al0s 2p.t0 as 19 TiontaIlnicFiCal143Sol'n, (uAgx 0.025 liters) 7.3150 13.0625 4.1800 2.3525 1.3075 0.1300 E STootla'lsatC E14q3uiiln, (nB gx 0.025 liters) 6.9775 12.1450 4.0075 2.3050 1.2475 0.1275 oFnG S1o4i3l,Adsxfomr,beudg/g ( (-E) X 10Sougs/omigl) 16873..55 34.5 9.5 12.0 0.5 COJ6RY Co 10 TABLE V FC 143 Desorption Isothern Data* A ESqouliult.ionC,oneC., fn n/1 (ColumnB, Table 428759..810000 19620..230000 54.9.190000 3 iEnqufiilr.stCoDmees.orption Solutton, mg/l. IV) 2487..86000000 1170..27000000 06..61000000 c EiqnuiSle.conCodneD.esorp- EiqnuiTlh.irdConDee.sorption tion Solution, me/l. _solution, mg/l. 46..8800000000 32..4000000000 0.08100000000 32..5900000000 20..0500000000 00..2001000000 AomnouSnott,Adxs/omr,bed vals (Column , TABLE 16873..550000 349..550000 102..500000 AAmfotuerntFiornstSoiDlesorp- TV)ela Sion 15604..865000 203..205500 30..420500 3 AAmfotuenrtSeocnonSdoiDlesorp- AAfmtoeurntThoinrdSoDtelsorp- sls tion alg tion 13581..605000 89..590500 2-0..055000 13255..115000 -100..665500 -0L.355005 w#i*tCohlucmosrre,ctGi,onanfdorHtwheereamocuanltculofateFdC 1i4n3thten stahmee2.w5ayulasofCosloulmutFi,onTArBeLmEaiInVing from the previous step in each case (See Materials and Methods Section). 03628 Lo n 200 sop p70 i : _-- [EE A I EA : 3 100 >: -- -- => Le x =3 50 c 5 om A YR-=SQU-A1R6E.D3 =+ 00..39836X 28 3 5 : - -50 0 100 200 300 400 s00 Equil. Conc., C, mg/l FIGURE 4 FC 145 ADSORPTION AND DESORPTION ISOTHERSS . daSneodsloirFdptlairienoendeiisssoobtrehpsetrtimosnf.itdaAta'adssoproapirtneitsoandsfooirrspottthiheoernmT,eisspoeDtcohtteitrveneddacltoiannceespnotiarnrtaest.ieosntsiB.,matC,edD, E, GENERAL COMETS The FC 95 and FC 143 adsorption coefficients from these experiments Bay be converted to the analogous constants based on soil organic carbon conten Ky, with the equation K,( = 100 K/(% organic carbon) giving 8K, of 45 for FC 95 and 17 for FC 143 (2.2% organic carbon for this soil). Comparing these values to those in TABLE VII, it can bo seen that FC 95 and FC 143 are at the low end of the spectrum, again indicating high mobility of these compounds. 03629 : 12 TABLE VI FC 143 MATERIAL BALANCE A Total FC 143 (ICnonilgtu.imanlDl,y in Solution Table IV) 71.3.30165250 - 42..13850205 - 1.030s75 5 FC 143 in Solution (CaotluEmqnuiEl,.,TABmgL.E IV) 162..91747550 42..03007550 1.02.417257 c FC 143 on Soil a(tA Eq-uilB.), mg. 00..93157755 00..10742755 00..00062050 oD FAimrosutntDeRseomropvteidonb,y mg. 00..0089342550 00..0076232755 00..0004337050 c sToortbaeld AbmyouTnhticeDe- Desorptions, mg (D+E+F) 00..2211280 00..11060983 0.0.00055350 E SAmeocuonntd. DReesmoorvpetdiobny, mg. 00..0066130000 00..0052085205 0.0.000061725 H SoAinlounAtfteRrema3inDiensogrpo-n tions, mg. C-G 00..617265755000 0-.00.00533225500 0-.0.000062572550 Yor TAhmiorudntDReesmoorvpetdionb,y ng. 00..007656275500 00..004068570500 00..000030500205 I ApmeorucnetntDeosforAbmeoduntasAd- sorbed (G/C x 100) 2662..384195 21928..110186 28081..705000 F"CCol24u3mnsinD,27E.,5 amlnd (F25wmelreadodbetdainpeldusby2.5finrlstrceamlaciunliantginfgromthepraemvoiuonuts (sntge)p)of Oifn tshoelut2.i5onmlinofeacsholurteisopnectrievmeainsitnegp afnrdomthtehne psruebvtiroaucstinsgtept.he amount (ng) 03630 oo. 13 TABLE VII CofmopraraisSoenleoctfeAddsGorroupptioofn CPoeesftfiicciideensts (Hamaker andThompson} 1972) Chemical Koc - (nobile) C(hFlCorMa3nbe-n- = === ono?1)2.8 2(,C4-9D5 - = = woo.t.352) BPrroompahcainl 7s1 SMionnauzrionne 83 135 DPircohplaozbienneil 152 164 AChtlroarzoipnreopham 214752 APrnoemtertyonne 300 380 " DPiruornoetnryne 185 5 s13 + CPhalroarqouaxturon 240,,908060 _ = (imobile) DOT 243,000 The small amounts adsorbed and ease of desorption is consistent with the relatively high water solubility of FC 95 (300 mg/1) and Fc 143 (>20 g/1.) and with the chemical nature of the molecules - organic salts which ionize in aqueous solution: CF) 505K CF C0, NH, : FC 95 FC 143 03631 1 / Terns DPM - Disintegrations per minute - Concentration of chemical in solution at equilibrium x/m - Concentration of chemical adsorbed on soil at equilibrium RZ - Coefficient of determination KX - Adsorption coefficient K' = Desorption coefficient N - Exponential tem in Freundlich Equation . N' - Exponential tern for desorption equation Koc - Adsorption coefficient based on soil organic carbon content References DavidPseosnt,icJi.deM.M,oveetm.entalT.,hro1u9g75h,SoUEis1eFs.oAfU-.So6iSl.6PEP0aAr,a7me2te-rs7fo5r -De0scr0ib3in.g DavidisnonS,oiJl.s,"M.,pre1s9e76n,ted"VeatrtiScyamlpoMsoivuemmeonntNoannbdioDliosgtirciablutTiroannsopforOtrgaanndics . STOfrtaannsfdoarrsdatsi,onGaoifthPeorlslbuutragn,tsWDo.n,MLaand y 1a1n-d13, W1a9te7r,6.st National Berea Hamakienr,thJe. SoW.ilanEdnvJi.roMm.enTth.ompsCo.n,A. 191.72.Gor"iAndgsoarnpdtiJo.n Wi.nROarsgakneicr (Cheedmsic)a:ls farce]Dekker, Tnc., N. Y. HamakCehre,micJa.lsW,.,Hu1n9a75n,He"aIlnttherapnrdetathteionEnovfirSoomielntL,eaAchiCnoglleEcxtpieornimeonftsD,o"w Sicnienti- Fic Papers, Vol. 1, Dow Chemical USA, Midland, Wich. 48630 ~~ ' 03632