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Data Evaluation Record on the anaerobic biotransforma1;ion of dimethyl disulfide in watersoil systemPMRA Submission Number C .)EPA MRID Number 4705282049520-1-4C (p. 14).Not reported.12.79 mCUmmol(2.667 mCUmL; p. 14; Table 34 p. 30).Reviewer-calculated 0.0205 mCUmmol(0.0043 pCi/mL);0.156 mg/mL [14 ]dimethyldisulfide 97.4 m4mLunlabeled dimethyl disulfide (purity 99.5%, Lot ho.:14514BA; p. 14, Table 3, p. 30).Location of the radiolabel: At each methyl C.Storage conditions of O C in darkness (p. 14; Appendix 1, p. 49).test chemical:Lot/B atch No.Analytical purity:Initial specific activity:Final specific activity:?hvsico-chemical r o e r t iofe sdimethvl disulfide:--ParameterValueMolecular weightMolecular formulaWater solubilityVapor- pressure94.2 glmoleCJ%S?.Comment--AW Absorption1 28.7 mm Hg.At 297.5 nm, molar absorptivity( E ) 37.32 (MI, cm-l).I Not reported.I Not reported.I At 25 C.MRID 470528021IIStability of compound at room temperature3ata obtained from p. 14 of the study report and Appendix 2, p. 29 in MRID 47052802.Page 6 of 37IIII

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number { .)EPA MRID Number 70528202. Water-soil collection, storage and propertiesIIDescriptionWater:Soil:Pesticide use history at the collection siteWater:Collectionprocedures forSoil:Water:Sampling depth forDetailsINot applicable; deionizedl (Milli-Q) water used as test wat&r.IRolinda, California.No pesticides or fertilizer for at least 4 years previous to cqllection.I,Not applicable.Geographic locationI(Soil:- ---II1Not reported.Not applicable.Not reworted.Not applicable.Maintained at ca. 4 O C in unsealed bags prior to use.Not applicable.Water:Soil:Water:Storage length1 3 months.Soil:Notapplicable.Water:Preparation2-mm sieved.Soil:Data obtained from p. 15; Figure 1, p. 35; Appendix 1, p. 52 of the study report.Storage conditionsPropertyTemperature ("C)WHRedox potential (mV)Oxygen concentration (%)Dissolved organic carbon (%)I--Hardness (mg CaC03/L)IIIIIIIIIIDetailsNot applicable as deionized (Milli-Q) water was used as the testwater.Not determined.1INot determined.INot determined.INot determined.IINot determined.Not determined.Electrical conductivity (mmhos/cm)Not determined.Microbial biomass/population (units)Data obtained from p. 15; Figure 1, p. 35 of the study report.Page 7 of 37III1

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number 1. .IPropertySoil texture% Sand (2000-50 km):% Silt (50-2 pm):% Clav ( 2 um):pH (soil:water, 1:1)Organic carbon (%)IOrganic matter (%)CEC (meqI100 g)Redox potential (mV)Moisture at 113 atm (%)EPA MRID Number 470528204Details1Sandy loam.Not reported.Not reported.67.40.50.86.9Not determined.Not reported.I IIIIIData obtained from p. 15; Appendix 1, p. 52 of the study report.1 Percent organic carbon determined by primary reviewer using the following formula: organic carbon (%) organic matter (%)/1.72.2 Although the study protocol specified that microbial biomass was to be determined in the test soil priortotreatment, no results were provided (Appendix 1, p. 52).B. EXPERIMENTAL CONDITIONS:1. Preliminary experiments: Preliminary experiments were conducted and determined that thestandard "flow through" test system would not be suitable (p. 8). This resulted in develdpmentof a test system that would minimize diffusion of dimethyl disulfide.In one of the experimental systems, a static KOH trapping solution was maintained insi e theincubation bottle (p. 21). LSC analysis determined that 16% of the applied radioactivit wasrecovered in the KOH solution after 8 days of incubation, and 85-91% at 16-27 days. S nce,dimethyl disulfide was not expected in the KOH solution, the study author proposed that[14c]methanethiol was being formed; however, methane thiol was known to oxidize to (limethyldisulfide (p. 21). Consequently, an internal KOH trapping solution was not used.9In an additional preliminary experiment, that appeared to utilize the trapping system useg for thedefinitive experiment, [14 ]residuesrecovered in the KOH trapping solution comprised 16.8%and 29.6% of the applied at 14 and 21 days posttreatment, respectively, with 14c02only accounting for 3.0% and 4.6% of the applied, respectively (Table 5, p. 32).2. Experimental conditions:PParameterDuration of the testWater:Details71 days.Page 8 of 37

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number { .)EPA MRID Number 47052820I1ParameterDetails1--Filteredlunfiltered water:1IType and size of filter used, if any:Water:Amount of soil andwater per treatmentSoil:1I1 35 mL (2- to 3-cm layer).Waterlsoil ratioIINominal:Actual:Application rates(mg a.i./L)1(Control conditions, if usedNo. of replicationsvIDeoxygenated (nitrc gen-sparged),deionized ( i l l i - d water)usedIas test water.ca. 25 g wet wt.ca. 1.4:l (35 rnL:ca. 25 E wet wt.).279 mg a.i./L (9.75 mg a.i.1system).280 mg a.i./L (9.81 mg a.i.135 mL water).No sterile controls were used.1IIII11IiNo sterile controls were used.IDuplicate treated water-soil systems at each collectio? interval.250-mL bottle (120composition not repseptum capTwo-stage SKC Anamg front:50 mg back, 150 mg total sorbent).1N KOH (two traps) to trap C02; the first KOH trapseptum-sealed, 60-mL borosilicate, glass vial)sorbent tube, with a second KOH trap (50 mLwashing bottle) placed after the solid sorbentFigure1. D. 35)."Systems were incubated closed and attached to a volatilestra ing system on collection.Ethanol; final concentration 0.3% based on water volu-ne (100IpL ethanol in 35 mL water).Control, if used:Treated:Test apparatus (type/materiallvolume):Details of traps for C 0 2 and organic volatiles,if any:Ir1 If no traps were used, is the system closed?Identity and concentration of co-solventI Test materialVolume of the testsolution usedltreatment:application method Application method(e.g.: mixedlnot mixed):Any indication of the test material adsorbingto the walls of the test apparatus?1 mass/populationSoil:(units) of treatedITemperature ("C):ExperimentalContinuous darkness1 conditions(YesNo):-- 100 pL.IIITest solution was applied, via glass syringe, "through" the waterlayer across the top of the soil layer.Not indicated.INo sterile controls were used.ITreated systems were not analyzed for biomass.'I1 20 f 2 C.Yes.IAt the time of preparation of the water-soil systems, sob moistureData were obtained from pp. 8-9, 14-16; Tables 1-4, pp. 28-31; Figure 1, p. 35; Appendix 1, pp. 52-53 of h e studyreuort.1 *Althoughthe study protocol specified that microbial biomass was to be determined in treated and untreited soil at,study termination, no results were provided (Appendix 1, p. 52).IIPage 9 of 37

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number { .)EPA MRID Number 470528203. Anaerobic conditions: Soil was transferred to the incubation bottles and the headspa epurged (flow rate not reported) with nitrogen for 30 seconds (p. 15). Deoxygenated (nitdogensparged), deionized (Milli-Q) water was then added over the soil and nitrogen wasthrough the water layer for 30 seconds, with a final purge of the headspace for 10the bottles were sealed and maintained at 20 2EC in darkness for "several" days (interfa1 notspecified) prior to treatment (p. 15; Appendix 1, p. 53). No determinations, such as redoxpotentials or dissolved oxygen concentrations, were made to verify that anaerobic conditionswere achieved and maintained.4. Supplementary experiments: None reported.Page 10 of 37

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number { .)EPA MRlD Number ,470528205. Sampling:Details,0 (5 min.), 3,7, 14,21 and 71 days.Duplicate treated water-soil systems at each interval.Upon sampling, the 1N KOWsolid-phase carbon tKOH volatiles traps were connected to thevia an outlet needle. An inlet needle connected th incubationbottle to a nitrogen gas-filled Atmosbag. The nitrogen gaswas then drawn (100-150 a m i n u t e , 4 hours) thrdugh theincubation bottle and traps via vacuum pump, with1 theAtmosbag re-filled with nitrogen gas as needed.Method of collection of C 0 2 and organic volatilecompounds1ISampling intervalsltimes for:Sterility check, if sterile controls are used:Redox potential, dissolved oxygen, pH:No sterile controls were used.Not measured.,Water layer and soil were separated and soil extrabted theSample storage before analysisday of collection. Any storage of water layer and/c/r soilextracts prior to ainalysis was not reported.IIOther observations, if anyNone.IIData were obtained from pp. 15-17; Table 4, p. 31; Figure 1, p. 35 of the study report.1IC. ANALYTICAL METHODS:Separation of the soil and water: Duplicate aliquots (volume not reported) of the watdr layerwere taken and analyzed for total radioactivity by LSC prior to decanting from the soil (Ipp.1718). Duplicate aliquots (volume not reported) of the 0- and 21-day water layers were adalyzeddirectly by HPLC as described below (pp. 17, 20).k'Extraction/clean uplconcentration methods: Soil was transferred to a 250-mL, wide- outhNalgene bottle and sequentially extracted once with deionized water (75 mL), followed y twicewith acetonitrile (50 mL x 2) and a final extraction again with water (50 mL, p. 17). Ea hextraction was done via mechanical shaking (mechanism type not reported) for 15 minutes; afterwhich, soil and extract were separated by centrifugation (3,500 rpm, 10 minutes).aliquots (volume not reported) of each extract were analyzedl for total radioactivity17-18).iIncubation bottle rinse. After removal of the soil, the incubation bottles were rinsed wit methanol (25 rnL) to recover any residual [14 ]residues,with duplicate aliquots (volume1notreported) analyzed for total radioactivity by LSC (p. 17).Total 14cmeasurement: Total 14cresidues were determine,dby summing the concentrdtions ofresidues measured in the water layers, soil extracts, extracted soil, bottle rinse and volatilestrapping materials (Table 4, p. 3 1).Page 11 of 37I

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number 1.IEPA MRID Number 47052820Determination of non-extractable residues: Aliquots (weight, replicates not reported) ofextracted, wet soil were analyzed for total radioactivity by LSC following combustion (pp. 1718).Determination of volatile residues: KOH solutions. Duplicate aliquots (volume not reiported)the KOH trapping solutions were analyzed for total radioactivity by LSC (pp. 17-18). Aliquotsof selected KOH solutions from the "first" trap that preceded the solid-phase carbon trai werealso analyzed by HPLC and GCMS as described below (pp. 18,20; Figure 1, p. 35).Neutralization of KOH solutions. The study author proposed that methane thiol was beingformed and re-oxidized to dimethyl disulfide (p. 21). To recover [14 ]dimethyldisulfidl formedfrom the re-oxidation of [14 ]methanethiol, aliquots of selected KOH solutions were a4usted toneutral pH with HCl, then purged with nitrogen and the released [14 ]residuesdrawn though asolid-phase (CSC) carbon trap. The nitrogen-sparged neutra lizedKOH solution was analyzed byHPLC and the solid sorbent extracted and analyzed as described below.Solid-phase (CSC) carbon trap. The trap was opened and the sorbent divided into two,approximately equal, portions; "front" and "rear" of the trap (p. 16). Each portion was dxtractedtwo to three times with hexane; extraction solvent volumes were 5.0 mL (Table 7, p. 34).Extraction was done via mechanical shaking (mechanism nod specified) for 15 minutes; afterwhich, extract was drawn off via pipette. Duplicate aliquots (volume not reported) of eachextract were analyzed for total radioactivity by LSC, and an aliquot (volume not reported of theinitial hexane extract was analyzed by HPLC and GCMS as described below (pp. 16-17).Aliquots (weight, replicates not reported) of the extracted sorbent were analyzed for totdlradioactivity by LSC following combustion (p. 17).Derivatization method, if used: None was reported.Identification and quantification of parent compound: Aliquots of the 0- and 21-day waterlayer samples, 7-day solid sorbent hexane extract, 21-day KOH trapping solution (trap thatpreceded solid-phase carbon trap), and 14- and 21-day KOH trapping solutions after pHneutralization were analyzed using reverse-phase HPLC under the following conditions: BetasilC-8 column (4.6 x 100 rnrn, 5 pm), column temperature ambient, either isocratic mobile phasecombining 0.1% formic acid in methanol (A) and 0.1% aqueous formic acid (B) at A:B, 70:30(v:v, run time 10 min.) or gradient mobile phase [percent A:B at 0-3 min. 0: 100 (v:v), 518 min.70:30, 10 min. 0:100], injection volume 50-100 pL, flow ratle 1 mllminute, and radioactivitydetector (mechanism type not specified, p. 20). Parent [14c]dimethyldisulfide was bycomparison to the retention time of labeled reference standard (Figures 7-9, pp. 41-43).Aliquots of the 14- and 21-day initial solid sorbent hexane extracts and KOH trapping solutions(same intervals) were analyzed using GCMS under the following conditions: Varian 38b0GCl1200 MS system, Supelco SPB-1 Sulfur column (0.32 lrun x 30 m, 4 p film thicknesg), flowrate 1.2 Wminute, temperature gradient 40-200 C at 4O0C/minute, electron ionization (EI), ionmode positive, electron energy -70 eV, detector and discharge voltage 1,500 V, manifoldPage 12 of 37

Data Evaluation Record on the anaerobic biotransformation of dimethyl disulfide in watersoil systemPMRA Submission Number { .)EPA MRID Number ,47052820temperature 40 C, ion source temperature 150 C, transfer line temperature 200 C, scad modecentroid, scan time 0.25 second (pp. 18-19). Parent [ 1 4 ] d i e t hdisulfideylwas identified bycomparison to the retention time of reference standard (Figures 4-5, pp. 38-39).Identification and quantification of transformation proclucts: Methanesulfonic acid (MSA).MSA was detected and quantified using reverse-phase HPLC as described for the pareqtcompound; however, a chromatogram of reference standard MSA wasFigures 8-9, pp. 42-43). Identification of MSA was confirmed viareported) in 21-day neutralized KOH solution (p. 22; Figure: 10, p. 44).chromato ram of reference standard MSA was not provided, the chromatograms of the21-daysample [I fCIMSA were comparable to chromatograms of reference standard MSA (LCbS-ESI)provided in the dimethyl disulfide aerobic soil metabolism study (Appendix 2, pp. 78-78 inMRID 47052819) submitted concurrently with this study.IMethane thiol (as re-oxidized [14 ]dimethyldisulfide) was detected and quantified via QCMSand HPLC as described for parent compound (pp. 21-22; Figure 4, p. 38; Figures 6-7, pb. 40-41;Figure 9, p. 43).Identification of 14coz. Aliquots (1 mL) of the KOH solutions were combined with 1M bariumchloride solution ( K O H : B C1:1, ,v:v) and refrigerated overnight (p. 18). The sample wereBthen vortexed for ca. 10 seconds, allowed to stand (interval not reported) and centrifugep (3,000rpm, ca. 2 minutes). Total radioactivity in the KOH solutions was determined via LSC rior toand after barium chloride precipitation. The resulting precipitate was also re-suspended in 1NHC1 solution and analyzed by LSC.I?Methane. To determine if methane was present, the volatile trapping system was modified forone of the 71-day water-soil systems in the following manner:the Atmos bag (nitrogen gas) was removed from the incubation bottle inlet,the initial KOH trapping solution of 25 mL in a septum-sealed, 60-mL borosilibate,glass vial was changed to 50 mL in a glass, gas-washing bottle, andfollowing the solid-phase (CSC) carbon trap, headspace gases were passed thro/ugh aGCIRAM oxidation reactor tube (700 C) and a second KOH trapping solutionThis system was designed to trap [14c]methanethiol and l4c02in the initial KOH trappsolution, parent [14 ]dimethyldisulfide on the solid-phase carbon sorbent, then oxidize bny[14c]methaneto 14c02.No reference compounds were reported for identifying transformation products of dimetPlyldisulfide.Detection limits (LOD, LOQ) for the parent compound and transformation produ s:Limits of Detection (LOD) and Quantitation (LOQ) were not reported.Page 13 of 37

Data Evaluation Record on the anaerobic biotransformaltion of dimethyl disulfide in watersoil systemPMRA Submission Number { .)EPA MRID Number 4705282011. RESULTS AND DISCUSSIONA. TEST CONDITIONS: After the initiation of anaerobic conditions (flooding withdeoxygenated, deionized water; static nitrogen atmosphere), the water-soil systems werdincubated for "several" days (interval not specified) prior to treatment. No determinatioljls, suchas redox potentials or dissolved oxygen concentrations, were made to verify that anaero icconditions were achieved and maintained. Additionally, no records were provided to es ablishthat the incubation temperature was maintained at 20 f 2OC throughout the study ( e d1,dp.i x51).1B. MATERIAL BALANCE: Overall recovery of radiolabeled material averaged 87.9 % 6.8%(range 72.3-97.9%, n 11) of the applied, with no consistent pattern of decline in total abpliedradioactivity throughout the incubation (DER Attachment 2, Reviewer's Comment No. 1 ).Fourhours following application of [14 ]dimethyldisulfide into the water layer ca. 67-69% of theapplied had volatilized, while the remaining [14 ]residuespartitioned between the water 'layerand sandy loam soil with mean (n 2) distribution ratios (wz1ter:soil) of 3: 1 at day 0 (4 hours)and 1:1 at 3-7 1 days (DER Attachment 2).Page 14 of 37

Data Evaluation Record on the anaerobic biotran

the water-soil system, the compound was found to degrade tlo methane thiol, methanesullfonic acid, methane and C02 with low levels of formation of bound soil residues. provided; half-lives