Document QJ9D9aBz5d7Rk3Rk4dnLvO8jk
:
AR226-0184
ATTACHMENT TO LETTER TO C. AUER DATED MAY 4, 2000: ONGOING
ENVIRONMENTAL STUDIES ON PERFLUOROOCTANESULFONATES
Physical/Chemical Properties
`sPeoatrecnhtiralegFalrudoirnogcphoetmeinctailalCfoomrbfuosrtmiatoinoBnyo-fPrfolodruicntdsat(eidnvdoilovxeisnsraevnidefwuroafrness),ul3tsMoEfnvliitreorantmuernetal
Laboratory. Expected completion: Sept. 2000. Study painp proe gresr s.
Fluorochemical Decomposition Process: Quantification and Assessment (involves
computational chemistry calculationsofbond-breaking strengthsof sulfonated
ppearpfelruionropcrhoegmriecsasls), Battelle Memorial Institute. Expected completion: Aug. 2000.
Study
Environmental Fate and Transport
Abiotic Degradation Studies (hydrolysis and indirect photolysis), 3M Environmental Laboratory. | + Expected completion: June 2000 (hydrolysis); Aug. 2000 (indirect photolysis). (Summary study
plan and screening results summary being providetod EPA)
M
Biodegradation Studies (aerobic acclimated closed bottle biodegradation, aerobic soil/sediment
2% biodegradation, pure culture aerobic, and fluorochemical decomposition process, stability in
24.a - Sasa 3H HT pen water, photodegradation), Springborn Laboratories, Inc. Expected completion: Aug. 2000.
(Summary `plan being provided to EPA) |
.
3 _ PFOS: A 96-Hour Toxicity Test with the Freshwater Alga (4nabaena flos-aquae), Wildlife
International, Ltd. Expected completion: July 2000. (Protocol being provided to EPA)
Y- PFOS: A 96-Hour Toxicity Testwiththe Freshwater Diatom (Naviculapelliculosa), Wildlife International, Ltd. Expected completion: July 2000. (Protocol being provided to EPA)
PFOS: A 96-Hour Toxicity Test with the Marine Diatom (Skeletonema costatum), Wildlife
5- International, Ltd. Expected completion: July 2000. (Protocol being provided to EPA)
( PFOS: A 7-Day Toxicity Test with Duckweed (Lemna gibba), Wildlife International, Ltd. ~ Expected completion: July 2000. (Protocol being provided to EPA)
p Ne
Phytotoxicity -- Seedling Emergence, Wildlife International, Ltd. Expected completion: July
2000. Protocol in progress.
Environmental Monitoring
Global Environmental Sampling Plan, Michigan State University. Expected completion: Dec.
2000. (Summary being provided to EPA)
004457
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Abiotic Degradation Studies of Perfluorooctane Sulfonate
Purpose of Study:
`The purpose of this investigation is to determine the abiotic degradation reactions, rates and productsofthe potassium saltof perfluorooctane sulfonate (PFOS or FC-95). These results will be used to aid in the determinationof the environmental fateofthis compound.
Significance of Study
When assessing environmental fate of production chemistries, there are four `main factors taken into account. The first factor, environmental entry, considers the rate and media into which the substance enters the environment. The. second factor, transport of the compound, concerns its physical and chemical properties such as solubility, vapor pressure and sorption to soil and sediments. These factors, when taken together, determine its movement in the environment. Third, the rateoftransformation due to environmental degradation via biotic and aebnivoitriconpmreoncteswsheesreartehetackoemnpiontuonadccooruintts,traanndsfloasrtmesidnkpsr,odpulcatcecsolilnectthse, are considered. Computer models then combine the information and are used to trace the rates of movement, transformation and distribution among the media of the environment as a function of time. Real world measurementsof the degradation products and manufactured chemistries are conducted and correlated with models. Only with al of the above information can a full environmental assessment be conducted. The present study will provide information on abiotic degradation reactions, rates and products so that the assessment will have increased reliability and exposure issues will be more completely resolved.
Objectives
`There are three primary abiotic degradation process in the environment: hydrolysis, photolysis and oxidationreduction. Each process will be studied individually in controlled experiments to identify decomposition products and to evaluate the kinetics. The resultsof these experiments, when taken as a whole, will lead to a more complete picture of the abiotic degradation of PFOS in the environment
Proposed Degradation Route and Products
tis proposed that abiotic degradation may lead to direct cleavageofthe C-S bond to produce a CF7 radical, followed by subsequent rearrangements to produce a variety of compounds. Thus, the expected degradation products may include perfluorooctanoic acid (PFOA), perfluoronated Cs olefins, and mixed Cs hydrides. This type of mechanism is unknown in the scientific literature.
'
04458
Alternatively there may be production of SO, via a sulfonite intermediate. This tsyuplefoonfammeidcehaannidssmulifsaknnatoewcnheinmitshterileist.er"at2urTehifosrsbuogtgheshtysdrtohcatarPbFonOSbamsaeyd undergo abiotic degradation. Protocol
GLP Status memObneersgooafltohfet3hiMs sctoumdmyuisnittoygaivnedftaostt,haocsceuriandtievaidnudalrselpiearbfloerdmaitnagto select environmental fate and assessment determinations. A second goal is to present the results in peer-reviewed journals for broader distribution and review of study integrity. Further, this data will be viewed by various government entities. However, these studies are research and an all-inclusive protocol cannot be written. With this notable exception, the studies will be conducted in compliance with GLP-type regulations.
Adsorption/Desorption Characteristics and Recoveries A "preliminary * adsorption/desorption study, demonstrating acceptable analyte recovery for both PFOS and PFOA will be conducted per OECD Method 106, "Adsorption/Desorption." A reportof the findings will be included in the final report, Homologues of Cs materials will be assumed to behave in a similar manner to the Ca compounds. It is assumed that possible volatile degradation compounds (e.g. olefins, hydrides etc.) will show little adsorption to the matrix or the container. Degradation products not herein predicted will not be assessed for adsorption/desorption properties if mass balance for that portionofthe study is in excess of 85% Analytical Method(s) Validation Analytical methods will be validated for each specific target material on each piece of analytical instrumentation. The methodology for method validation will be included in the final report. Data Analysis An analyst trained on software specific to that instrument on which the data will be collected will perform data work-up. Kinetic determinations, quantum tyiheeldlse,adefifnivceisetnciygactaolrcautlatthieon3sManEdnvmiercohnamneinsttailcLealbuocriadtaotriyo.n wiAlll bdeatpaewrilflorbmeed by reviewed internally in the environmental lab, externally by Dr. Robert Voyksner at tDhaveisR.esearch Triangle Institute and by Dr. Don Crosby at the Univ. of Californi--a
2
04459
Quality Control An analysis will be deemed acceptable when the following quality control criteria are met: The standard deviation of triplicate analysis is less than 8%. Spiked samples show greater than 80% recovery for all target analytes. Instrument blanks and quality control blanks show less than 10% of the lowest qquuaannttiattaitoinonmluesvtelhdaevteeramcionrerdelfaotrioenaccoheftfaircgieetntinotfh0e.a9n9aolrygsrise.ateCru.rvReessiudsueadlfsoor n the curve are less than 20%. Internal standard response must show less than an
8% standard deviation.
Sample Purity NMR, GCMS, HPLCUTMS, HPLC\MS\TOFMS, IC\CD and ICPMS will be used to analyze the PFOS used in this investigation for purity prior to use. Impurities contained in the production chemistry will be monitored for degradation. All chemicals used in the study will be logged into the environmental laboratory chemical tracking database.
Hydrolysis Studies
parAentstcuodmypoofuhnyddroalsytwiecllreaasctiinofnosrmlaetaidosntoonitnfhoesrtmaabtiilointyoonftphoesspiebrlseisrteeanccteioofn the products. In order to be representative, hydrolysis studies shoud be carried out at pH values normally found in the environment (pH 4 to 9), and under physiological conditions (pH 1 to 2). A pH 11.0 buffer will be added in the present study to better understand the behavior of FC-95 in basic solutions. Two types of Solutions wil be studied. The first study will be conducted in homogeneous solutions which contain only the fully solvated species in a buffer. The methodology for this portionofthe study is based on that used by the 3M
Environmental Laboratory and the U.S. Environmental Protection Agency* with
stheeveexnc-ewpeteikonpetrhiaotd.a tTothaelosfeeciognhdt sseerpiaersatofe tteismtes pwoililntbsewcilolnbdeucctoeldleicntebdufofveerreda ssltuurdriieess',(teharceeh tiynp5e:s1 owfastoeilr csooirlrmeisxptounrdeis)n.g tBootthhosseeriuessewdililnbaedsrournptaitoenl/edveastoerdption temperatures (50-70 C).
In dilute solutions, the rate law for a hydrolysis reaction is shownbythe
following equations. It is important to note that the equations must be modified in
solutions that are not dilute.
F -d(PFT OS) = knlPFOS)
or
n (PFOSt ), yt
FOS), 3
04460
The halflife of the compound ata specific pH is related to the rate of hydrolysis
by:
(0.693)
ty = --
Using will be
the equations monitored to
above, the concentration of calculate the hydrolysis rate
PFOS in constant
tahnedahqaluf-eloifue.s
bIfufafneyrsloss
cofalFcCul-a9t5edishoalbfsleifreveisd
the less
degradation products will than five years, a second
be determined. f the study will be initiated
over
multiple temperatures and multiple pH's to determine the kinetic order and rate of
reaction.
9.0,Aaqnudeo1u1s.0saacmcpolredsinwgilltobpeupblriesphaerdedEiPnAbugfufiedrelsionleust.ioTnhseofbupfHfe=rs1s.e5,le5c.t0e,d7.w0il,l be
HthPoLsCe IpMubSliasnhaleydsibsy.
EFPivAe-mmeithaloidq,uootrs
used because they are acceptable buffers for of PFOS at ca. 2.00 ug/ml in aqueous buffer
will be added to 40 ml VOA vials. One set of samples for each time point and
`each pH will be placed inside an orbital shaker held at a constant temperature of
50C. These will be prepared in triplicate with one additional replicate for spike
recovery data. One set of blanks, containing only the buffer at each pH and for
ttiimmee pionitnetr,vablsu,t awistehtoouft sPaFmOpSl,ewviilallaslwsiollbbeeipnuclllueddedfofroranqaulaylsiitsy. coTnthreol.saAmtplseelsewcitleld
be diluted standard,
with and
aeniatlheyrzeidsobpyroHpyPlLaCl/coMhSolfoorr
PmeFtOhSancoolncceonnttraaitniionn.g
a
suitable
internal
Slurry samples will be prepared by first wetting each of the three dried and characterized Soils with 0.01 M CaClz (1:10 soil to CaCl) in 40 mi VOA vials for atleast 24 hours at room temperature. Following this, the liquid wil be pored off and a volume of buffer (pH = 1.5, 5.0, 7.0, 9.0, and 11.0) equal to the amount of CaCl, removed will be added. A 10 uL spike of PFOS will then be added ata predetermined concentration sufficient to give a ca. 2.00 pg/ml concentration in aqueous buffer. One set of samples for each time point and each pH wil be placed inside an orbital shaker held at a constant temperature of 50C. These will be prepared in triplicate with one additional replicate for spike recovery data. One set of blanks, containing only the buffered slurry at each pH and for time point, but without PFOS, will also be includedfor quality control. At selected time intervals, a set of sample vials will be pulled for analysis. The samples will be sditlauntdeadrwdi,tcheenittrhiefrugiesdoparnopdylanaallcyozheold obrymHePthLaCn/oMlScofnotraPinFiOngSacosnucietnatbrlaetiinotne.mal
The solvents chosen for dilution and preparation of reagents (IPA and mbeeitnhganaonla,lyrezsepdecitsisvoelluyb)lea.reSowlautteiro-nssolwuibllebesodlevgenatssseindwphriicorhttohseasmupbljeect material preparation. Biodegradation of the analyte by microbial growth in the buffered media should be excluded because of the study being conducted at 50C, a
.
c04461
temperature that is forbidding for most mesophillic microorganisms (the type
found in laboratory settings)
Indirect Photolysis Studies
Due to minimal light absorption in the UV/Vis region by many 3M fluorochemicals, the indirect mechanism of photolytic decomposition will be:
studied*. The indirect mechanism can be defined as a chemical or electronic
excitation transfer froma lightabsorbing species to the target species which
sionudrucceeswisllombee utsypeed otfo cihnedmuicceadltchheafnogrem.atiIonn tohfersaedisctauldsiefsr,opmhhoytdornosgfernompetrhoexilidgeht
contained in the solution.>* These radicals in tum reacted with the.
fiuorochemicals to produce the chemical changes discussed below.
PFOS will be exposed to simulated sunlight in increasingly more "dirty" or complex environments [water spiked with hydrogen peroxide, synthetic humic water, natural lake water and soil slurries (three types of soil). These exposures will test how each environment affects the photolytic mechanism. Achieving near mass balance by accounting for all parent and product species is a necessary goal, so that meaningful comparisons between the results of each photolytic epxropdouscutrespceacniebsetao spsaerstisceudl.ateIstias nedxpoercgtaenidcthmaatteardisaolrspwtiilolnionfdubcoethchpaarnegnetsainndthe photolytic behaviorover the pure water system. However, what these effects will
be is highly speculative.
`Samplesfor the pure water portion of this investigation will be prepared as
fnogl/lmolwsw.illFibvee
atdodtewdenttoy4m0lmalliVquOoAtsvoifalPs FaOndS
sipniwkaetdewriatth
a concentration
10 pL of a 30%
of ca.
H,0,
2.0
stroilpultiicoanteiwniwtahtterw.o Fadoduirtisoentasl orfepslaimcpatleessffoorrsepaikceh rteicmoevpeoriyntdawtiall. bTewporespeatrsewdilinbe exposed to the light source, the other two will be kept dark but held at the same temperature. Four sets of blanks, containing only the analyte but without the H,0; will be set up for each time point. Again, two sets will be exposed to the light source; the two other will be kept dark but held at the same temperature. Four sets of blanks, containing the HzO; but without the analyte will be set up for each time point. Two sets will be exposed to the light source, theother two wil be kept dark but held at the same temperature. The vials will be inverted and
placed in a custom designed liquid cooling bath contained in the test chamber of
an Atlas Suntest CPS Plus light stability chamber. A xenon-arc lamp (simulated
tsiunmleigohft6)8wi-t7h2aho3u3r0snwmith--t8h0e0Hn;m0;nsootlcuhtifoinltebrewiilnlgbsepitkuemdeidn oenacfhoraapnpreoxprpioastuerevial
at 24 hour radiometer
intervals. Light interfaced to a
intensity personal
wciolmlpbueterre.coSradmepdluessinwgilla
tchoemnmerrecmioavled
and
divided for analysis by dynamic purge and trap gas chromatography/mass
spectrometry (GC/MS) for volatile degradation products. High performance liquid
chromatography/mass spectrometry (HPLC/MS) will be used for non-volatile and
s
C04462
semi-volatile analysis. lon chromatography/conductivity detection (IC/CD) will be used for sulfite, sulfate, sulfonamidic acid, trifluoroacetic acid and free fluoride analysis.
`Samples will be prepared as follows for the synthetic humic water portion of the investigation. Synthetic humic water will be prepared as per EPA pcornocceendturraet.i"onFoifvcea.to 2t.w0enptgy/mmllwiallliqbueotasdodfePdFtOo S40inmisyVnOthAe.ticFohuurmsiectwsaotfesraamtpales for each time point will be prepared in triplicate with two additional replicates for spike recovery data. Two sets will be exposed to the light source while the other two will be kept dark but held at the same temperature." Four sets of blanks, containing only the analyte but without the synthetic humic water will be set up. for each time point. Again, two sets will be exposed to the light source; the two other will be kept dark but held at the same temperature. Four sets of blanks, containing only the synthetic humic water butwithout the analyte will be set up for each time point. Two sets will be exposed to the light source, the other two will be kept dark but held at the same temperature. The vials will be inverted and placed in a custom designed liquid cooling bath contained in the test chamber of a Atlas Suntest CPS Plus light stability chamber. A xenon-arc lamp (simulated sunlight) with a 330 nm -- 800 nm notch filter will be turned on for an exposure time of 68 -71 hours. Light intensity will be recorded using a commercially built radiometer interfaced to a personal computer. Samples will then removed and analyzed by dynamic purge and trap gas chromatography /mass spectrometry (GC/MS)forvolatile degradation products. High performance liquid chromatography/mass spectrometry (HPLC/MS) will be used for non-volatile and semi-volatile analysis. lon chromatography/conductivity detection (IC/CD) will be used for sulfite, sulfate, sulfonamidic acid, trifluoroacetic acid and free fluoride analysis.
`Samples for the lake water portion of this investigation will be prepared as follows. Five to twenty mi aliquotsof PFOS in lake water at a concentration of ca. 2.0 pg/ml will be added to 40 ml VOA vials. Four sets of samples for each time point will be prepared in triplicate with two additional replicates for spike recovery data. Two sets will be exposed to the light source, the other two will be kept dark but held at the same temperature. Four sets of blanks, containing only the analyte will be set up for each time point. Again, two sets will be exposed to the light source; the twootherwill be kept dark but held at the same temperature. Four sets of blanks, containing the lake water but without the analyte will be set up for each time point. Two sets will be exposed to the light source, the other two will be kept dark but held at the same temperature. The vials will be inverted and placed in a custom designed liquid cooling bath contained in the test chamber of a Atlas Suntest CPS Plus light stability chamber. A xenon-arc lamp (simulated sunlight) with a 330 nm -- 800 nm notch filter will be tumed on for an exposure time of 68 -72 hours. Light intensity wil be recorded using a commercial radiometer interfaced to a personal computer. Samples will then removed and analyzed by dynamic purge and trap gas chromatography/mass
6
04463
spectrometry (GC/MS) for volatile degradation products. High performance liquid chromatography/mass spectrometry (HPLC/MS) will be sed for non-volatile and suesmeid-vfoolratsiullfeitaen,asluylsfiast.e, lsounlfcohnraommiadtiocgraacpihd,y/tcroinflduuocrtoiacveittiyc daectiedcatinodn f(rIeCe/fClDu)orwiidlel be analysis.
Slurry samples will be prepared by first wetting eachofthe three dried and characterized soils with 0.01 M CaCl; (1:10 soil to CaCly) in 40 ml VOA vials for
at least 24 hours at room temperature. Following this, the liquid will be pored off and a volume of water equal to the amountofCaCl, removed will be added. A 10 pL spike of PFOS will then be added at a predetermined concentration sufficient
to give a ca. 2.00 pg/ml concentration in water. The vials will then be spiked with 10 pL of a 30% HO; solution in water. Four setsofsamples for each time point
will be prepared in triplicate with two additional replicates for spike recovery data. Two sets will be exposed to the light source, the other two will be kept dark but held at the same temperature. Four setsof blanks, containing only the analyte will be set up for each time point. Again, two sets will be exposed to the light source; the twoother will be kept dark but held at the same temperature. Four
sets of blanks, containing only the soils will be set up for each time point. Again,
two sets will be exposed to the light source; the two other will be kept dark but
sheetlduaptftohreesacahmetitmeemppeorinatt.urTe.woFosuetrssweitlsobfebelxapnkoss,edcotnotatihneinlgighotnlsoyuwractee,rtwhiellobtheer two will be kept dark but held at the same temperature. The vials wil be inverted and placed in a custom designed liquid cooling bath contained in the test chamber of a Atlas Suntest CPS Plus light stability chamber. A xenon-arc lamp (simulated sunlight) with a 330 nm -- 800 nm notch filter will be tured on for an aexnpaodsduirtieontailme10ofu6L8a-l7i2quhootuorfs.a 3S0am%plHezs;, bsloalnutkisoannidn wcaotnetrrowlhsewirlel baeppsrpoipkreidatweith
every 24 hours. Light intensity will be recorded using a commercial radiometer interfaced to a personal computer. Samples will then removed and analyzed by dynamic purge and trap gas chromatography/mass spectrometry (GC/MS) for volatile degradation products. The samples for non-volatile analysis will be
dsitlauntdeadrdw,ithceenittrhiefrugiesdoparnopdylanaallcyozheold obrymheitghhapneorlfcoornmtaanicneinlgiqauisduictharbolmeaitnotgermaaplhy! mass spectrometry (HPLC/MS). lon chromatography/conductivity detection f(rIeCe/CfDlu)orwiildlebaenaulsyseids.for sulfite, sulfate, sulfonamidic acid, trifluoroacetic acid and
Oxidation/Reduction Studies
Oxidation/reduction mechanisms are well known to occur in the abiotic
doengerasdpeactiifoinc otfypmea-noyxicdlaatsisoensboyffceorrmipcoouxniddes,.'a*2r'eacTthiiosn iwnevlelstkingoatwinontowiollccfuorcuisn on natural systems. This reaction has been shown to occur in both thepresence Oabnsdearvbasteinocnes offrsoumnltihgehste(ecaxtpaelrytiimceonxtisdamtaioyn haenldp iinndeilrueccitdpahtoitoonlyosfisr)e.sults2from both
,
04464
hydrolytic and photolytic slurry studies, as the various oxides may be present in differing concentrations in the sols. Oxidation by TiOz underthe same
conditions will serve as a control experiment. >
Samples for this portion of the investigation will be prepared as follows. Five to twenty ml aliquots of PFOS in water at a concentrationofca. 10.0 pg/ml and a metal oxide concentration of 100 ug/ml will be added to 40 mi VOA vials. This gives approximately 50:1 molar excess of metal oxidesto ensure sufficient concentration to induce any possible abiotic degradation. One-haolf the vials. will be spiked with 10 uL of a 30% H;0; solution in water. Sixteen sets of `samples for each time point will be prepared in triplicate with two additional replicates for spike recovery data (eight with the iron oxides, four of which will have H,0; added and eight with TiOy, four of which will have H;0, added). Eight sets will be exposed to the light source, the other eight will bekeptdark but held atthe same temperature. Sixteen sets of blanks, containing the H,02 and metal oxide without the analyte will be set up for each time point (eight with the iron oxides, four of which will have H;0, added and eight with TiO, fourofwhich will have H.0; added). Eight sets will be exposed to the light source, the other eight will be kept dark but held at the same temperature. The vials will be inverted and placed in a custom designed liquid cooling bath contained in the test chamber of a Atlas Suntest CPS Plus light stability chamber. A xenon-arc lamp (simulated sunlight) with a 330 nm -- 800 nm notch filter will be tumed on for an exposure time of 160-168 hours with the H;0; solution being spiked in the appropriate vials at 24 hour interval. Light intensity will be recorded using a commercial radiometer interfaced to a personal computer. Samples will then be removed and analyzed by dynamic purge and trap gas chromatography/mass spectrometry (GC/MS) for volatile degradation products. High performance liquid chromatography/mass spectrometry (HPLC/MS) will be used for non-volatile and semi-volatile analysis. lon chromatography/conductivity detection (IC/CD) will be used for sulfite, sulfate, sulfonamidic acid, trifluoroacetic acid and free fluoride analysis.
Timeline The study will be conducted in the 3M Environmental Laboratory. Select
portions of this investigation have been carried out, although a complete data and kinetic work up has not been finished or reviewed. Each major portionof the. investigation will have an individual preliminary report issued. A final report, `which will ie the separate portions together, will be issued prior to September 1, 2000.
.
004465
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-
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