ASTM D3976-1992(2010) Standard Practice for Preparation of Sediment Samples for Chemical Analysis《制备化学分析用沉淀样品的标准操作规程》.pdf

1、Designation: D3976 92 (Reapproved 2010)Standard Practice forPreparation of Sediment Samples for Chemical Analysis1This standard is issued under the fixed designation D3976; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o

2、f 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 practice describes standard procedures for prepa-ration of test samples (including the removal of occluded wate

3、rand 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 The values stated in SI units are to be regarded asstandard. No

4、other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, 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-bilit

5、y of regulatory limitations prior to use. For a specificprecautionary statement, see Note 3.2. Referenced Documents2.1 ASTM Standards:2D596 Guide for Reporting Results of Analysis of WaterD1129 Terminology Relating to Water3D1192 Guide for Equipment for Sampling Water and Steamin Closed Conduits4D33

6、70 Practices for Sampling Water from Closed ConduitsD4410 Terminology for Fluvial Sediment3. Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice, refer to Terminologies D1129 and D4410.4. Summary of Practice4.1 Samples collected (see Practice D3370 and Specifica-tion D1192) in

7、the field are screened to remove foreign objectsprior to homogenization for chemical examination and analy-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-eni

8、zation, then allowed to settle to remove most of theoccluded water.4.3 Moisture determinations are made 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

9、-moved by decantation. The results are corrected to those thatwould have been obtained on samples dried to constant weightat 105 6 2 C, on the basis of a moisture determination usinga separate sample.4.5 Analyses for semivolatile constituents (for example,mercury) are made on samples previously drie

10、d at a tempera-ture found to be adequate for the purpose, and specified in thecorresponding analytical procedure.4.6 Analyses for nonvolatile constituents are made onsamples previously dried to constant weight at 105 6 2 C.4.7 A flow diagram, outlining typical procedures, is shownin Fig. 1.5. Signif

11、icance and Use5.1 The chemical analysis of sediments, collected from suchlocations as streams, rivers, ponds, lakes, and oceans canprovide information of environmental significance.5.2 Sediment samples are inherently heterogeneous in thatthey contain occluded water in varying and unpredictableamount

12、s and may contain foreign objects or material notordinarily considered as sediment, the inclusion of whichwould 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.

13、4 Standardized procedures for drying provide a means forreporting analytical values to a common dry weight basis.1This practice 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 ed

14、ition approved June 15, 2010. Published December 2010. Originallyapproved in 1980. Last previous edition approved in 2005 as D3976 92 (2005).DOI: 10.1520/D3976-92R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual B

15、ook of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copy

16、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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

17、a basis for discrimination ofsediment and foreign objects or materials. Stainless steel ornylon 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

18、 steel sieves 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.

19、4,or7.5, or 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 o

20、r otherwise 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

21、). The bottom 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 sievingoperat

22、ion.6.5 Mix 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 inorg

23、aniccompound 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 4 C or lower for a period of time not to exceed 1 week isrecommended

24、, although it 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,

25、asnecessary.FIG. 1 Flow diagram for Sediment-Sample TreatmentD3976 92 (2010)27.2 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 co

26、ntainer and composite themto obtain a representative sample of size suitable 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

27、7.3.7.5 Determine semivolatile and nonvolatile constituents,using samples prepared in accordance with 7.3 and Section 8.7.5.1 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 num

28、ber of smaller 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 por

29、celain dish,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, weighed withan accuracy of 60.1 mg. The use of samples smaller than 1 gis not recommended for moisture determination.8.3 Transfer the dishes containing th

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

31、les withthe 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 u

32、sually determined 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 2 C.9.2 Report all analytical values (see Method D596), regard-less of how m

33、easured, on the basis of a sample dried at 105 62 C 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 2 C.9.3.1 Test Method

34、 ACalculate volatile 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 anal

35、ysis; nonvolatile 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 t

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38、s have not received 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 mul

39、tiple 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D3976 92 (2010)3