1、Designation: D 3974 81 (Reapproved 2003)e1Standard 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 las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTESection 17 on Keywords was added editorially in June 2003.1. Scope1.1 These practices describe the partial extraction of soils
3、,bottom sediments, suspended sediments, and waterborne ma-terials to 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, mo
4、lybdenum,nickel, potassium, sodium, strontium, vanadium, and zinc fromthe 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
5、, cobalt, copper, iron, lead,manganese, nickel, and zinc from the preceding 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-d
6、rying.1.2.2 Air-drying at room temperature.1.2.3 Accelerated air-drying, 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 accompa
7、nying the instrumentused. Also see various ASTM test methods for determiningspecific 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 e
8、lement analysis provides more infor-mation than total metal analysis 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 This standard does not purport to address all of thesafety concern
9、s, 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 ASTM Standards:D 887 Practice for Sampling Water-Formed De
10、posits2D 1129 Terminology Relating to Water3D 1193 Specification for Reagent Water33. Terminology3.1 Refer to Terminology D 1129.4. Summary of Practices4.1 The chemical portion of both practices involves aciddigestion to disassociate the elements complexed in precipi-tated hydroxides, carbonates, su
11、lfides, 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).44.2 These practices provide samples suitable for analysisusing flame or flameless ato
12、mic-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 previously either not present or werefound in trace amounts. Con
13、sequently, it is important to be ableto measure the concentration of these pollution-depositedelements to properly study pollution effects.1These practices are under the jurisdiction of ASTM Committee D19 on Waterand are the direct responsibility of Subcommittee D19.07 on Sediments, Geomor-phology,
14、and Open-Channel Flow.Current edition approved June 10, 2003. Published July 10, 2003. Originallyapproved in 1981. Last previous edition approved in 1999 as D 3974 81 (1999).2Annual Book of ASTM Standards, Vol 11.02.3Annual Book of ASTM Standards, Vol 11.01.4The boldface numbers in parentheses refer
15、 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.5.2 This procedure is concerned with the pollution-relatedtrace elements that are described in 4.1 rather than thoseelements incorporated
16、 in the silicate lattices of the mineralsfrom which the sediments were derived. These pollution-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 lo
17、cked in the silicate lattices are notreadily available in the biosphere (1-8).5.3 When comparing 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
18、of a given traceelement can be adsorbed on the surface of fine, particulatesamples (4). For 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 cl
19、ay) is normalized. It hasalso been observed that the greatest contrast between anoma-lous 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 natu
20、ralparticle-size distribution (14.1). Fracturing a particle disruptsthe silicate lattice 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. Inte
21、rferences6.1 The only interferences are those encountered in the finaldetermination of metals 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 Watchglasse
22、sUse ribbed watchglasses to cover thedigestion beakers. These covers should fit loosely to 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, nyl
23、on, 10, 20, and 80-mesh.7.5 Petri Dishes, large.7.6 Freeze-Drier.7.7 Polyethylene or Polypropylene 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 Reagents Reagent grad
24、e chemicals shall beused in tests.Acids must have a low-metal content or should bedoubly distilled and checked for purity. Unless otherwiseindicated, all reagents shall conform to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety.58.2 Purity of WaterReferences
25、 to water shall be under-stood to mean reagent water conforming to SpecificationD 1193, Type 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 n
26、itric acid(HNO3). The acid must be low in metallic ions.8.5 Metal Solutions, StockPrepare 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 ho
27、od.10. Sampling10.1 Collect the sediments using an appropriate technique(see Practice D 887).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. Immedia
28、tely pack and cool the samplesfor shipping.10.4 Store samples at 4C if analysis is to be performedwithin 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 g
29、lassware and implements inHNO3(1 + 1) for 3 to 5 min.11.3 Rinse all glassware and implements 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 su
30、bsampling (5.3.2).12.3 Drying Samples:12.3.1 Preparation IFreeze-drying is rapid and results 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 cons
31、tant weight. This procedure requires a long timeto complete and the sample must be covered to avoid dustcontamination.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical
32、Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D 3974 81 (2003)e1212.3.3 Preparation IIIAccelerated air-drying the samples,for example, 95C is fo
33、llowed by allowing the samples to coolin a desiccator. Dry to constant weight. Often constant 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 m
34、ethod.13. Percent Solids Determination13.1 Using desiccated, tared-beakers, weigh the well-mixedwet 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 s
35、olids as described in 16.1.14. Digestion Practice A14.1 Crush the sample to facilitate weighing 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 r
36、eagent/glassware blank.14.3 Add the following to each sample and the blank:14.3.1 Water, 100.0 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 wi
37、th ribbed watchglasses and heaton a hot plate at 95C. To prevent splattering do not allow thesolutions 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 tran
38、sfer thesolution to a 50-mL volumetric flask and dilute to volume.15. Digestion Practice B15.1 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 wit
39、h each set of samples.15.2 Add 95 mL of water and 5.0 mL of HCl (sp gr 1.19) tothe sample and 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 (
40、overnight).15.4 Filter solution by suction filtration or filter paper.Quantitatively transfer 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
41、of the sample,M = dry weight of the sample (13.3), andN = wet weight of the sample (13.1).16.2 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 th
42、e reagent/glassware blank (14.2 and 15.1), g/mL,V = volume of extract from 14.6 and 15.4,U = 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
43、):A 5 C 3B100(3)where:A = metal per gram of wet sample, g,B = percent solids of the sample, andC = trace element per gram of dry sample (16.2), g.17. Keywords17.1 extraction; sediments; toxic; trace elementsD 3974 81 (2003)e13REFERENCES(1) Inland Waters Directorate, Analytical Methods ManualEnvironm
44、ent,Canada Inland Waters Directorate, Water Quality Branch, Ottawa,Canada.(2) Rubin, A. J., Aqueous 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 A
45、quatic Sediments,” Analyst,Vol101, 1976, pp. 761767.(4) Agemian, H., and Chau, A. S. Y., “A Study 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
46、, I., Smee, B. W. and Larson, J. O., “TheApplication of Different Analytical Extractions and Soil 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
47、and Technology, Vol II, No. 3, 1977, pp.277282.(7) Burrell, D. C., Atomic Spectrometric Analysis 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 Techno
48、logy, Vol 7, 1973, pp.135137.(9) Hawkes, H. E., and Webb, J. S., Geochemistry in Mineral Exploration,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 st
49、andard 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. Your comments are 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 me
