ASTM D3976-1992(2005) Standard Practice for Preparation of Sediment Samples for Chemical Analysis《化学分析用沉淀样品制备的标准实施规范》.pdf

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1、Designation: D 3976 92 (Reapproved 2005)Standard Practice forPreparation of Sediment Samples for Chemical Analysis1This standard is issued under the fixed designation D 3976; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes standard procedures for prepa-ration of test samples (including the removal of occluded w

3、aterand moisture) of field samples collected from locations such asstreams, rivers, ponds, lakes, and oceans.1.2 These procedures are applicable to the determination ofvolatile, semivolatile, and nonvolatile constituents of sedi-ments.1.3 This standard does not purport to address all of thesafety co

4、ncerns, if any, associated with its use. It is theresponsibility 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. For a specificprecautionary statement, see Note 3.2. Referenced Documents2.1 AS

5、TM Standards:2D 596 Guide for Reporting Results of Analysis of WaterD 1129 Terminology Relating to WaterD 1192 Specification for Equipment for Sampling Waterand Steam in Closed Conduits3D 3370 Practices for Sampling Water from Closed Con-duitsD 4410 Terminology for Fluvial Sediment3. Terminology3.1

6、DefinitionsFor definitions of terms used in this prac-tice, refer to Terminologies D 1129 and D 4410.4. Summary of Practice4.1 Samples collected (see Practices D 3370 and Specifica-tion D 1192) in the field are screened to remove foreign objectsprior to homogenization for chemical examination and an

7、aly-sis. Large objects are mechanically removed and small ones areeliminated by sieving the sample through a 10-mesh (2-mmopenings) sieve.4.2 Wet, sieved samples are mixed for preliminary homog-enization, then allowed to settle to remove most of theoccluded water.4.3 Moisture determinations are made

8、 on separate samplesfrom those analyzed for volatile or semivolatile constituents.4.4 Analyses for volatile constituents are made using wet,settled samples from which supernatant liquid has been re-moved by decantation. The results are corrected to those thatwould have been obtained on samples dried

9、 to constant weightat 105 6 2C, on the basis of a moisture determination usinga separate sample.4.5 Analyses for semivolatile constituents (for example,mercury) are made on samples previously dried at a tempera-ture found to be adequate for the purpose, and specified in thecorresponding analytical p

10、rocedure.4.6 Analyses for nonvolatile constituents are made onsamples previously dried to constant weight at 105 6 2C.4.7 A flow diagram, outlining typical procedures, is shownin Fig. 1.5. Significance and Use5.1 The chemical analysis of sediments, collected from suchlocations as streams, rivers, po

11、nds, lakes, and oceans canprovide information of environmental significance.5.2 Sediment samples are inherently heterogeneous in thatthey contain occluded water in varying and unpredictableamounts and may contain foreign objects or material notordinarily considered as sediment, the inclusion of whic

12、hwould result in inaccurate analysis.5.3 Standard methods for separating foreign objects tofacilitate homogenization will minimize errors due to poormixing and inclusion of extraneous material.5.4 Standardized procedures for drying provide a means forreporting analytical values to a common dry weigh

13、t basis.6. Preliminary Treatment of Field Samples6.1 The analytical sample is arbitrarily defined as that whichpasses a 10-mesh (approximately 2-mm openings) sieve. Thepurpose of this is to provide a basis for discrimination ofsediment and foreign objects or materials. Stainless steel or1This practi

14、ce is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology,and Open-Channel Flow.Current edition approved July 1, 2005. Published August 2005. Originallyapproved in 1980. Last previous edition approved in 2001 as D 3

15、976 92 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 B

16、arr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.nylon sieves may be used when inorganic constituents are to bedetermined. Stainless steel or brass sieves are suitable for usewhen organic substances are to be determined.NOTE 1For inorganic analyses, stainless steel siev

17、es are acceptableprovided the mesh is not soldered or welded to the frame. For organicanalyses, organic materials such as rubber or plastics should not be usedin the storage or handling of samples.6.2 Sieve dry samples without further pretreatment andfollow the procedures given in 7.3, 7.4,or7.5, or

18、 a combina-tion thereof, as appropriate.6.3 Vigorously stir wet field samples, which may havesettled during transit, to incorporate as much field water aspossible, thereby facilitating subsequent wet sieving.NOTE 2Do not add additional laboratory water since this may extractconstituents or otherwise

19、 change the composition of the sediment.However, it is permissible to slurry the sediment with a minimum quantityof field water collected with the sample, when necessary, to facilitatewet-sieving.6.4 Pass the wet sample, preferably as a slurry, through thesieve (plastic or stainless steel). The bott

20、om of an appropriatesize Erlenmeyer flask may be used to gently press the sedimentthrough the sieve, as necessary.6.4.1 Manually remove foreign objects such as stones,twigs, leaves, trash, etc., which would obviously not passthrough the sieve and which may interfere with the sievingoperation.6.5 Mix

21、 the sieved material by stirring and allow it to settlefor subsequent removal of supernatant liquid.6.5.1 Store the material, as prepared above, in contact withits supernatant liquid, until time of use for chemical examina-tion.NOTE 3Precaution: Samples intended for both organic and inorganiccompoun

22、d analysis may undergo changes in composition during storage.The analytical method should specify the conditions necessary to assurerequisite stability. In the absence of specific instructions, storage at atemperature of 4C or lower for a period of time not to exceed 1 week isrecommended, although i

23、t is known that microbiological activity does notcease under these conditions.7. Preparation of Analytical Samples7.1 Decant the supernatant liquid from the settled sedimentprepared in accordance with Section 6. Save the supernatantliquid for separate analysis of any suspended material, asnecessary.

24、7.2 Mix the sediment, using a glass rod or porcelain spatula,to minimize stratification effects due to differential rates ofsettling.7.3 Remove a number of small portions (at least ten) fromrandom locations in the sample container and composite themto obtain a representative sample of size suitable

25、for determi-nation of moisture (see Section 9), or for drying to preparematerial for analysis of semivolatile or nonvolatile constitu-ents.7.4 Determine volatile constituents, using wet samples pre-pared in accordance with 7.3.7.5 Determine semivolatile and nonvolatile constituents,using samples pre

26、pared in accordance with 7.3 and Section 8.FIG. 1 Flow diagram for Sediment-Sample TreatmentD 3976 92 (2005)27.5.1 Disaggregate the dried material by gently crushingany lumps or clumps in a mortar. Mix the disaggregatedmaterial and prepare a composite sample resulting fromremoval of a number of smal

27、ler portions as indicated in 7.3.The use of freeze drying facilitates sample disaggregation.8. Drying Procedure8.1 Use a sample prepared in accordance with directionsgiven in Section 7.8.2 Accurately weigh 5 to 10 g (61 mg) or 10 to 25 g (610mg) of the sediment into a previously tared porcelain dish

28、,weighed with the same accuracy.8.2.1 When a limited amount of sample is available, themoisture may be determined on 1- to 2-g samples, weighedwith an accuracy of 60.1 mg. The use of samples smaller than1 g is not recommended for moisture determination.8.3 Transfer the dishes containing the weighed

29、sediment toan oven and dry for2hasfollows:8.3.1 For determination of semivolatile constituents, use thetemperature (tC) specified in the analytical procedure for thatconstituent. For determination of nonvolatile constituents use105 6 2C.8.4 Cool in a desiccator, then weigh the dried samples withthe

30、same accuracy as the wet sample.8.5 Repeat drying at hourly intervals, to a constant weight.9. Moisture Correction and Calculations9.1 The possibility of loss of volatile constituents dictatesthe drying procedure that should be used, prior to chemicalanalysis. Volatile constituents are usually deter

31、mined usingundried samples. Semivolatile constituents must be determinedusing samples dried at a temperature at which no significantlosses occur. Nonvolatile constituents are analyzed usingsamples dried at 105 6 2C.9.2 Report all analytical values (see Method D 596), regard-less of how measured, on

32、the basis of a sample dried at 105 62C to facilitate correlation of data.9.3 The following equations are useful to correct analyticalresults, C (weight percent, g/g, etc.), obtained on an undriedsample or one partially dried at tC, to the basis of one dried at105 6 2C.9.3.1 Test Method ACalculate vo

33、latile constituents asfollows:Cv5 Cvl/100 2 % moisture105! (1)where:Cv= dry basis, andCvl= wet basis.9.3.2 Test Method BCalculate semivolatile constituents asfollows:Csv5 Csvl100 2 % moisture!/100 2 % moisture105!where:Csv= dry basis, andCsvl= dried at tC.10. Keywords10.1 chemical analysis; nonvolat

34、ile constituents; prepara-tion; sediment samples; semivolatile; volatileASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of

35、 any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments ar

36、e invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not rec

37、eived a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 3976 92 (2005)3