1、Designation: D 3974 81 (Reapproved 2008)Standard Practices forExtraction of Trace Elements from Sediments1This standard is issued under the fixed designation D 3974; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、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 These practices describe the partial extraction of soils,bottom sediments, suspended sediments, and waterborne ma-terials t
3、o determine the extractable concentrations of certaintrace elements.1.1.1 Practice A is capable of extracting concentrations ofaluminum, boron, barium, cadmium, calcium, chromium, co-balt, copper, iron, lead, magnesium, manganese, molybdenum,nickel, potassium, sodium, strontium, vanadium, and zinc f
4、romthe preceding materials. Other metals may be determined usingthis practice. This extraction is the more vigorous and morecomplicated of the two.1.1.2 Practice B is capable of extracting concentrations ofaluminum, cadmium, chromium, cobalt, copper, iron, lead,manganese, nickel, and zinc from the p
5、receding materials.Other metals may be determined using this practice. Thisextraction is less vigorous and less complicated than PracticeA.1.2 These practices describe three means of preparingsamples prior to digestion:1.2.1 Freeze-drying.1.2.2 Air-drying at room temperature.1.2.3 Accelerated air-dr
6、ying, for example, 95C.1.3 The detection limit and linear concentration range ofeach procedure for each element is dependent on the atomicabsorption spectrophotometric or other technique employedand may be found in the manual accompanying the instrumentused. Also see various ASTM test methods for de
7、terminingspecific metals using atomic absorption spectrophotometrictechniques.1.3.1 The sensitivity of the practice can be adjusted byvarying the sample size (14.2) or the dilution of the sample(14.6), or both.1.4 Extractable trace element analysis provides more infor-mation than total metal analysi
8、s for the detection of pollutants,since absorption, complexation, and precipitation are the meth-ods by which metals from polluted waters are retained insediments.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This stan
9、dard 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-bility of regulatory limitations prior to use.2. Referenced Documents2.1 A
10、STM Standards:2D 887 Practices for Sampling Water-Formed DepositsD 1129 Terminology Relating to WaterD 1193 Specification for Reagent Water3. Terminology3.1 Refer to Terminology D 1129.4. Summary of Practices4.1 The chemical portion of both practices involves aciddigestion to disassociate the elemen
11、ts complexed in precipi-tated hydroxides, carbonates, sulfides, oxides, and organicmaterials. Surface but not interstitially bound elements will bedesorbed in the case of clay mineral particulates. The silicatelattices of the minerals are not appreciably attacked (1-5).34.2 These practices provide s
12、amples suitable for analysisusing flame or flameless atomic-absorption spectrophotometry,or other instrumental or colorimetric procedures.5. Significance and Use5.1 Industrialized and urban areas have been found todeposit a number of toxic elements into environments wherethose elements were previous
13、ly either not present or werefound in trace amounts. Consequently, it is important to be ableto measure the concentration of these pollution-depositedelements to properly study pollution effects.5.2 This procedure is concerned with the pollution-relatedtrace elements that are described in 4.1 rather
14、 than those1These practices are under the jurisdiction of ASTM Committee D19 on Waterand are the direct responsibility of Subcommittee D19.07 on Sediments, Geomor-phology, and Open-Channel Flow.Current edition approved Oct. 1, 2008. Published November 2008. Originallyapproved in 1981. Last previous
15、edition approved in 2003 as D 3974 81 (2003)1.2For 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.3The boldface n
16、umbers in parentheses refer to the references at the end of thesepractices.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.elements incorporated in the silicate lattices of the mineralsfrom which the sediments were derived. These pol
17、lution-related trace elements are released into the water and read-sorbed by the sediments with changes in general water quality,pH in particular. These elements are a serious source ofpollution. The elements locked in the silicate lattices are notreadily available in the biosphere (1-8).5.3 When co
18、mparing the trace element concentrations, it isimportant to consider the particle sizes to be analyzed (8, 9).5.3.1 The finer the particle the greater the surface area.Consequently, a potentially greater amount of a given traceelement can be adsorbed on the surface of fine, particulatesamples (4). F
19、or particle sizes smaller than 80 mesh, metalcontent is no longer dependent on surface area. Therefore, ifthis portion of the sediment is used, the analysis with respect tosample type (that is, sand, salt, or clay) is normalized. It hasalso been observed that the greatest contrast between anoma-lous
20、 and background samples is obtained when less than80-mesh portion of the sediment is used (4, 5).5.3.2 After the samples have been dried, care must be takennot to grind the sample in such a way to alter the naturalparticle-size distribution (14.1). Fracturing a particle disruptsthe silicate lattice
21、and makes available those elements whichotherwise are not easily digested (6). Normally, aggregates ofdried, natural soils, sediments, and many clays dissociate oncethe reagents are added (14.3 and 15.2).6. Interferences6.1 The only interferences are those encountered in the finaldetermination of me
22、tals using atomic-absorption spectropho-tometry or other instrumental or colorimetric procedures.7. Apparatus7.1 Digestion BeakersUse only beakers made of borosili-cate glass or TFE-fluorocarbons.7.2 WatchglassesUse ribbed watchglasses to cover thedigestion beakers. These covers should fit loosely t
23、o allowevaporation of the digestion medium.7.3 Filter PaperThe qualitative grade paper employedshould be a fast filtering, hardened, ashless paper retaining bothcoarse and gelatinous precipitates.7.4 Sieves, nylon, 10, 20, and 80-mesh.7.5 Petri Dishes, large.7.6 Freeze-Drier.7.7 Polyethylene or Poly
24、propylene Bottles, wide-mouth,125-mL capacity.7.8 Suction Filtration Apparatus, 0.45-m filter.7.9 Automatic Shaker.7.10 Volumetric Flasks, 50 mL and 100-mL capacity.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in tests.Acids must have a low-metal content or should bedoubly d
25、istilled and checked for purity. Unless otherwiseindicated, all reagents shall conform to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety.48.2 Purity of WaterReferences to water shall be under-stood to mean reagent water conforming to SpecificationD 1193, Ty
26、pe II. The water shall be free of metallic contami-nants.8.3 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl). The acid must be low in metallic ions.8.4 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3). The acid must be low in metallic ions.8.5 Metal Solutions, StockPrepare
27、metal stock solutions,each containing 1000 mg/L of a metal of interest and eithernegligible or known concentrations of interfering metals.9. Precautions9.1 Digest the samples only in a laboratory ventilation hood.10. Sampling10.1 Collect the sediments using an appropriate technique(see Practice D 88
28、7).10.2 Retain and store that portion of sediment which passesthrough a nylon, 10-mesh sieve, 1-mm particle size (5.3).10.3 Store the sample in plastic bags or plastic bottles thatcan be tightly sealed. Immediately pack and cool the samplesfor shipping.10.4 Store samples at 4C if analysis is to be p
29、erformedwithin 1 week. Otherwise, store the samples at 20C untilanalyzed.11. Glassware Cleaning11.1 Immerse all glassware and implements in a hot solutionof HCl (1 + 1) for 3 to 5 min.11.2 Second, immerse all glassware and implements inHNO3(1 + 1) for 3 to 5 min.11.3 Rinse all glassware and implemen
30、ts repeatedly withwater following the acid washes.12. Sample Preparation12.1 Completely thaw frozen samples before unsealing.12.2 Preparation of the samples for analysis may involvecompositing, splitting, or subsampling (5.3.2).12.3 Drying Samples:12.3.1 Preparation IFreeze-drying is rapid and resul
31、ts inloose samples. See the apparatus instruction manuals forfurther information.12.3.2 Preparation IIAir-drying at room temperature isaccomplished by spreading the samples out on petri dishes anddrying to constant weight. This procedure requires a long timeto complete and the sample must be covered
32、 to avoid dustcontamination.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and
33、the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D 3974 81 (2008)212.3.3 Preparation IIIAccelerated air-drying the samples,for example, 95C is followed by allowing the samples to coolin a desiccator. Dry to constant weight. Often constant
34、 weightmay be achieved by drying overnight, however, constantweight must be obtained for consecutive measurements. Whenanalyzing for more volatile metals, use the temperature recom-mended for that specific method.13. Percent Solids Determination13.1 Using desiccated, tared-beakers, weigh the well-mi
35、xedwet samples from 12.2 or 12.3. Record the weights.13.2 Dry overnight or to constant weight at 105C and allowthe samples to cool in a desiccator.13.3 Reweigh the beakers and samples. Determine thepercent solids as described in 16.1.14. Digestion Practice A14.1 Crush the sample to facilitate weighi
36、ng if a hardaggregate is formed during drying (5.3 and 12.3).14.2 Weigh4gofdried sample into a 250-mL beaker.Record the sample weight to the nearest 0.1 mg. Include anempty beaker in each analysis set as a reagent/glassware blank.14.3 Add the following to each sample and the blank:14.3.1 Water, 100.
37、0 mL.14.3.2 Concentrated HNO3(sp gr 1.42), 1.0 mL.Afoamingreaction indicates the presence of carbonates; in this case addthe acids slowly.14.3.3 Concentrated HCl (sp gr 1.19), 10 mL.14.4 Cover the beakers with ribbed watchglasses and heaton a hot plate at 95C. To prevent splattering do not allow the
38、solutions to boil or bump.14.5 Remove each beaker from the hot plate when thesolution remaining is 10 to 15 mL. Allow the contents to coolto room temperature.14.6 Filter each solution and quantitatively transfer thesolution to a 50-mL volumetric flask and dilute to volume.15. Digestion Practice B15.
39、1 Weigh 1.0000 g of dried sediment and place in a125-mL polypropylene wide-mouth bottle. For low-level traceelements use up to 10 g of sediment sample. Include an emptybottle as a reagent/glassware blank with each set of samples.15.2 Add 95 mL of water and 5.0 mL of HCl (sp gr 1.19) tothe sample and
40、 to the blank bottle and cap tightly. In the caseof a foaming reaction, which indicates the presence of carbon-ates, add the acidic solution slowly.15.3 Shake at room temperature in a mechanical shaker 16h (overnight).15.4 Filter solution by suction filtration or filter paper.Quantitatively transfer
41、 the solution to a 100-mL volumetricflask and dilute to volume.16. Calculation16.1 Use the following equation to determine the percentsolids of the sample (Section 13):B 5MN3 100 (1)where:B = percent solids of the sample,M = dry weight of the sample (13.3), andN = wet weight of the sample (13.1).16.
42、2 Calculate the concentration of the element for each drysample as follows:C 5Q 2 S!VU(2)where:Q = concentration of the element in the digested solutiong/mL,S = concentration of the trace element found in the reagent/glassware blank (14.2 and 15.1), g/mL,V = volume of extract from 14.6 and 15.4,U =
43、weight of the sample corrected to a dried sample at105C, g, andC = trace element per gram of dry sample, g.16.3 Use the following equation to determine the concen-tration of the metal in the wet sample (13.1):A 5 C 3B100(3)where:A = metal per gram of wet sample, g,B = percent solids of the sample, a
44、ndC = trace element per gram of dry sample (16.2), g.17. Keywords17.1 extraction; sediments; toxic; trace elementsD 3974 81 (2008)3REFERENCES(1) Inland Waters Directorate, Analytical Methods ManualEnvironment,Canada Inland Waters Directorate, Water Quality Branch, Ottawa,Canada.(2) Rubin, A. J., Aqu
45、eous Environmental Chemistry of Metals, Ann ArborScience Publishers, Inc., Ann Arbor, Mich., 1974.(3) Agemian, H. and Chau,A. S. Y., “Evaluation of Extraction Techniquesfor the Determination of Metals in Aquatic Sediments,” Analyst,Vol101, 1976, pp. 761767.(4) Agemian, H., and Chau, A. S. Y., “A Stu
46、dy of Different AnalyticalExtraction Methods for Nondetrital Heavy Metals in Aquatic Sedi-ments,” Archives of Environmental Contamination and Toxicology,Vol6, 1977, pp. 6982.(5) Bradshaw, P. M. D., Thomson, I., Smee, B. W. and Larson, J. O., “TheApplication of Different Analytical Extractions and So
47、il Profile Sam-pling in Exploration Geochemistry,” Journal of Geochemical Explo-ration, Vol 3, 1974, pp. 209225.(6) Malo, B. A., “Partial Extraction of Metals from Aquatic Sediments,”Environmental Science and Technology, Vol II, No. 3, 1977, pp.277282.(7) Burrell, D. C., Atomic Spectrometric Analysi
48、s of Heavy Metal Pollut-ants in Water, Ann Arbor Science Publishers Inc., Ann Arbor, Mich.,1974.(8) Oliver, B. G., “Heavy Metal Levels of Ottawa and Rideau RiverSediments,” Environmental Science and Technology, Vol 7, 1973, pp.135137.(9) Hawkes, H. E., and Webb, J. S., Geochemistry in Mineral Explor
49、ation,Harper and Row, New York, N.Y., 1962.ASTM 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 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
