1、Designation: E 2686 09Standard Test Method forVolatile Organic Compound (VOC) Solvents Absorbed/Adsorbed By Simulated Soil Impacted by PesticideEmulsifiable Concentrate (EC) Applications1This standard is issued under the fixed designation E 2686; the number immediately following the designation indi
2、cates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method simulates the application
3、 of an emul-sion of a pesticide emulsifiable concentrate (EC) to soil withhigh organic matter (corn cob granules) and to soil with highinorganic matter (clay granules) and determines the amount ofsolvent retained by the granules, and withheld from theatmosphere, before and after exposure to 40C in a
4、 ventedoven. The granules simulate two extremes of soil composition,and the 40C exposure simulates high temperature weathering.Solvent loss from organic substrates other than corn cob mayalso be determined by repeating the 40C exposure tests withthe chosen substrate replacing corn cob. The results w
5、ith corncob, however, are a reference that must be reported with thealternate substrate results. The difference in solvent content ofthe granules before and after weathering is an indication of theemission of the solvent from soil impacted by emulsions orsolutions during pesticide applications using
6、 common practicessuch as spraying and drip irrigating. Analysis of the granulesfor solvent content is by high pressure liquid chromatography(HPLC), gas chromatography (GC), or other methods testedand proven to be accurate and reproducible.NOTE 1Since it evaluates soil surface sorption, this test met
7、hod willunderestimate soil sorption from pesticide applications made below thesoil surface. Sub-soil surface treatments may include, but are not limitedto, mechanical soil injection and soil incorporation applications. In thesecases, the increased depth of the sub-soil treatments reduce the soil sur
8、faceexposure and facilitate increased levels of soil sorption.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is th
9、eresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 Other Standards:240 CFR 51.100(s) Protection of EnvironmentRequirements for Preparation, Adoption, and
10、 Submittal ofImplentation PlansDefinitions3. Terminology3.1 Definitions:3.1.1 absorb, va process in which one material (theabsorbent) takes in, and retains, through its pores and inter-stices the molecules of another material (the absorbate).3.1.2 adsorb, va process in which one material (theadsorbe
11、nt) attracts to, and retains on, its surface the moleculesof another material (the adsorbate).3.1.3 emulsifiable concentrate, na single-phase liquidsystem having the property of forming an emulsion whenmixed with water.3.1.4 emulsifying agent, na surfactant that promotes thesuspension of one liquid
12、in another.3.1.5 gas or liquid chromatography, na process in whicha chemical mixture carried by a mobile liquid or gas isseparated into components as a result of different affinities ofthe components for the liquid or gas and the adsorbing mediumthrough which they pass.3.1.6 inorganic matter, nsubst
13、ances of mineral origin thatare not characterized by primarily carbon-based structures.3.1.7 organic matter, nin soil, organic matter consists ofplant and animal material that is in the process of decompos-ing.3.1.8 tropospheric ozone, nan air pollutant formed by thesunlight catalyzed reaction betwe
14、en hydrocarbons and nitrogenoxides present in the troposphere, the layer of the atmosphereclosest to the earths surface.3.1.9 volatile organic compound (VOC), nany compoundof carbon, excluding carbon monoxide, carbon dioxide, car-bonic acid, metallic carbides or carbonates, and ammonium1This test me
15、thod is under the jurisdiction of ASTM Committee E35 onPesticides and Alternative Control Agents and is the direct responsibility ofSubcommittee E35.22 on Pesticide Formulations and Delivery Systems.Current edition approved April 1, 2009. Published June 2009.2Available from U.S. Government Printing
16、Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.carbonate, which participates in atmospheric photochemicalreact
17、ions; excluded is a list of organic compounds which havebeen determined to have negligible photochemical reactivity(40 CFR 51.100(s).3.1.10 volatilize, vto pass off as vapor; to evaporate.4. Summary of Test Method4.1 A pesticide EC (emulsifiable concentrate) is simulatedwith a concentrate consisting
18、 only of solvent plus emulsifyingagent(s). The concentrate is then mixed with water, and theemulsion is applied to corn cob granules (organic substrate)and montmorillonite clay granules (inorganic substrate), whichabsorb/adsorb the liquid.4.2 Other organic substrates, like corn stover, straw, orspha
19、gnum peat, for example, may simulate the harvest debrisfrom some crops better than corn cob, and the test method canbe used with any of this type substrate replacing corn cob. Caremust be taken to select a substrate appropriate for the crop ofconcern, and the results with corn cob are a reference th
20、at mustbe reported with the alternate substrate results. The treatedgranules are placed in a vented 40C oven in uncapped bottles.The uncapped bottles allow for loss of the solvent by volatil-ization. Each bottle is left in the oven for a different, and everincreasing, time period. The time period fo
21、r the first bottle maybe as little as two hours, and that for the last bottle may be asmuch as one-hundred twenty hours or longer. After the 40Cexposure, the granules are analyzed to determine the amount ofsolvent still retained. Successive time periods continue untilthe amount of solvent found in t
22、wo or more successive samplesindicates more exposure time is not expected to cause signifi-cantly more loss of solvent. Analysis is by high pressure liquidchromatography (HPLC), gas chromatography (GC), or othermethods tested and proven to give accurate and reproducibleresults.5. Significance and Us
23、e5.1 This test method is designed specifically for emulsionsof pesticide emulsifiable concentrates.5.2 This test method provides information on theabsorption/adsorption of solvents by simulated organic soil andinorganic soil impacted by pesticide EC emulsion applications.5.3 The amount of solvent lo
24、st by volatilization at 40C asdetermined by this method is an indirect measure of theatmospheric availability of the solvent to potentially react withnitrogen oxides to form tropospheric ozone, a major airpollutant.6. Apparatus6.1 Balance, sensitivity of 0.01 g.6.2 Roller System, two or more rollers
25、 with a drive bed,capable of rotating a glass bottle or jar, about 1 to 4 L in size,at 20 to 60 r/min.6.3 Glass bottle or jar, round, with screw-thread cap, for usewith roller system. Typical size is 1 to 4 L.6.4 Oven, vented, mechanical convection, 40 6 2C, 2.0 ft3minimum inside capacity, 50 to 90
26、air exchanges per hour.6.5 125-mL laboratory media bottles, glass, round, outsidediameter about 55 mm, height about 123 mm, inside diameteropening about 30 mm, with screw-thread caps. An example isWheaton brand, available from many laboratory supply com-panies.6.6 Apparatus required by the analytica
27、l test method.7. Reagents and Materials7.1 Corn cob granules, 20/40 Mesh7.2 Montmorillonite clay granules, LVM, 12/24 Mesh.7.3 Solvent to be tested.7.4 Emulsifying agent(s) suitable for emulsifying the sol-vent.7.5 Reagents and materials required by the analytical testmethod.8. Hazards8.1 Before tes
28、ting, read the precautionary statements onproduct labels and the Material Safety Data Sheets (MSDS).Take proper precautions to prevent skin contact and inhalationof fumes or dust. Take care to prevent contamination of thesurrounding area. Always wear the appropriate safety equip-ment and, where indi
29、cated, wear respiratory devices approvedby the National Institute of Occupational Safety and Health(NIOSH) for the product being tested.8.2 Store, handle, and dispose of test materials with consid-eration for health and environmental safety, and in accordancewith federal, state, and local regulation
30、s.9. Sampling, Test Specimens, and Test Units9.1 The uniform mixing of the roller system procedureensures any size sample taken from the roller system jar is arepresentative sample. Do not use riffling to reduce a grosssample of the treated granules to a representative, suitable size.Significant vol
31、atilization of the solvent may occur duringriffling or any other time the granules are not in a sealedcontainer.10. Preparation of Apparatus10.1 For all apparatus, see the manufacturers instructionsfor proper operation and maintenance.11. Calibration and Standardization11.1 See the analytical test m
32、ethod to be used for determin-ing solvent content for information relative to calibration andadjustment of the apparatus necessary for the use of themethod.11.2 See the analytical test method for the standardizationand use of reference standards and blanks used in the method.12. Procedure12.1 Prepar
33、e an emulsifiable concentrate consisting only ofsolvent plus emulsifying agent(s). A typical formula is 90 to92 % solvent and 8 to 10 % emulsifying agent(s). Check theemulsion performance by adding 1 part concentrate to 14 partswater. Stir the mixture to form the emulsion. The emulsionshould form ea
34、sily, remain free of separation for 15 min, andre-emulsify easily after sitting 24 h. If the concentrate does notmeet these performance limits, reformulate using a differentemulsifying agent(s). Keep the concentrate and the emulsion inclosed containers, regardless of the ambient temperature, toE2686
35、092prevent loss of solvent by volatilization. Open the containersonly for the time needed to perform a necessary task.12.2 Analyze the concentrate for weight % solvent, usingthe same analytical method to be used for the treated granules.Repeat the analysis. The two analyses must not differ morethan
36、4 % from each other. Use the average to calculate themakeup of the emulsion to be used for treating the granules.12.3 Prepare one batch of emulsion treated corn cob gran-ules and one batch of emulsion treated clay granules asdescribed below. These are the primary sampling units. Testunit samples are
37、 sub-units taken from these primary units.12.4 Keep all treated granules in closed containers, regard-less of the ambient temperature, to prevent loss of solvent byvolatilization. Open the containers only for the time needed toperform a necessary task.12.5 Typically, the desired weight % solvent in
38、granules foranalysis by HPLC or GC is about 1% %. A suggested protocolfor the preparation of granules with 1 % solvent is as follows:Prepare a concentrate of 90 % solvent plus 10 % surfactant(s).Add 1.1 parts concentrate to 14 parts water. Add the resultingemulsion to 85 parts granules and mix to un
39、iformity. Deter-mine the initial solvent content of the granules by extracting asample with a suitable analytical solvent followed by analysisof the extract. The weight of the sample, or test unit, for 40Cexposure and subsequent analysis is the weight determined tobe nominal for the analytical metho
40、d.12.6 Begin preparation of the two batches of treated gran-ules by adding untreated granules to the glass bottle or jar to berotated on the roller system. The granules should fill one-fourthto one-half the container for the best mixing by rotation tooccur.12.7 Add the emulsion to the granules in th
41、ree equalincrements using enough total emulsion to give good distribu-tion of the liquid but not enough to wet the granules to the pointof significantly changing their flow properties. Use a transferpipette to add the emulsion to the inside wall of the containerwhile the container is being tilted an
42、d rotated by hand. The goalis to spread the liquid in a thin film on the wall so that the liquiddoes not contact the granules in a concentrated area as wouldhappen by just pouring the liquid on the granules. Concentrat-ing the area where the liquid contacts the granules may causeclumps, which then r
43、equire extra mixing care to re-fragment .12.8 Add the first emulsion increment, promptly cap thecontainer, and place it on the roller system at, typically, 30 to50 r/min for a good cascading motion that gives good mixingof the granules inside. Rotate 10 min. Repeat the incrementadditions of emulsion
44、 and 10 min rotating two more times.12.9 Use an analytical method tested and proven to giveaccurate and reproducible results. HPLC and GC methods havebeen used successfully.12.10 Determine by trial and error the number of successivetime periods needed for tracking the loss of solvent from thegranule
45、s by volatilization at 40C to a plateau indicating furtherloss is not expected to be significant. A minimum of fivesuccessive time periods is needed to conclude the plateauoccurs; two of those periods must be 0 h and 72 h. Tracking iscompleted when the results from any two of three successivetime pe
46、riods do not differ from each other by more than theaccuracy of the test method. See 15.2 for repeatability andreproducibility standard deviation and the 95 % repeatabilityand reproducibility limits on the difference between testresults.In the rare event it is concluded that a plateau for loss byvap
47、orization will not be seen, the half-life for biodegradationof the solvent in soil can be used as a second tier end-point.Stop the testing after exposure time at 40C equals 33 thebiodegradation half-life. The determination of soil biodegrada-tion half-life, itself, is beyond the scope of this test.1
48、2.11 A suggested sequence of successive time periods at40C for starting trial and error tests is: 0 h, 8 h, 24 h, 48 h, 72h, 96 h, and 120 h.12.12 A suggested testing protocol is as follows: Preparethree sets of seven 125-mL media bottles containing the treatedgranules. Trial and error results may r
49、educe or increase thenumber of samples actually needed.12.13 Weigh the empty bottle and cap to the nearest 0.01 g.Add a test unit (nominal weight) of granules to the bottle.Typically, the nominal weight of granules for HPLC analysis is5 g, and the nominal weight for GC analysis is 5 to 20 g. Usethe nominal weight specified by the analytical method for all40C exposures and solvent extractions.12.14 Weigh the bottle and granules and cap to the nearest0.01 g. Determine the exact weight of the granules to thenearest 0.01 g.12.15 For each set of seven bottles, lab
