1、Designation: D 5435 03Standard Test Method forDiagnostic Soil Test for Plant Growth and Food ChainProtection1This standard is issued under the fixed designation D 5435; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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. Scope*1.1 This test method covers the determination of quantity(Q) and intensity (I) results for several elements in soils, spoi
3、ls,fly-ash, and other soil substitutes to ascertain their suitabilityfor the growth of vegetation and possible adverse effects ofmetals on the food chain.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety problems, if an
4、y, 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 653 Terminology Relating to Soil, Rock, and Conta
5、inedFluids2D 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and Construction2E 617 Specification for Laboratory Weights and PrecisionMass Standards32.2 EPA Standard:U.S. EPA Method 3050 A23. Summary of Test Me
6、thod3.1 A representative sample material to be tested is air dried,sieved to pass a 2-mm screen, equilibrated for 16 to 20 h withthe soil test solution containing the optimum activities (I) ofH3O+,Ca+,Mg+,K+and DTPA (diethyl-enetriaminepentaacetate) to render a small exchange of metalsfrom the solid
7、 phase to the solution phase. This test method iscalibrated with respect to pH, K, Ca, Mg, H/(Ca + Mg)1/2,Mg/K, Ca/Mg, Mn, Fe, Cu, Zn, Al, Pb, Ni, and Cd. In additionto the exchangeable or labile amounts (Q), or both, of the sameelements, comparable levels of the negative logarithm valuesanalogous t
8、o pH may be calculated using the ligand constantsfor the respective elements.4. Significance and Use4.1 The bioavailability of chemical elements is poorlyrelated to the chemical composition of soils and plant growthmedia containing a mineral or any type of adsorbed phase. Thechemical potential (pi f
9、or element, i,) is an intensity parameter(I), and the sorbed amount in equilibrium with the soil solutionis a measure of the quantity (Q). These parameters for eachelement (essential or toxic) should be measured in the presenceof other elements at or near the desired intensity. This testmethod is th
10、e only method that generates these results simul-taneously for several elements. The computer software allowsthese values to be related to the total sorbed quantities of thedifferent elements. For many substrates, it has been found thatthe theory for the method holds to the degree that vegetationhas
11、 been established on many non-soil substrates and soil-water-food chain problems have been evaluated by this testmethod. This test method has been used on many sites inPennsylvania and other locations to monitor the effect ofsewage sludge applications on land as a source of essentialelements for pla
12、nts with no harmful effects on the food chain.It has also been used to evaluate synthetic soils produced fromfly-ash alone or as a component of coal refuse for theestablishment of vegetation on mine spoils, coal refuse piles,and abandoned mine lands.4.2 The quality of the result produced by this sta
13、ndard isdependent on the competence of the personnel performing it,and the suitability of the equipment and facilities used.Agencies that meet the criteria of Practice D 3740 are generallyconsidered capable of competent and objective testing/sampling/inspection/ and the like. Users of this standard
14、arecautioned that compliance with Practice D 3740 does not in1This test method is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.22 on Soil as a Mediumfor Plant Growth.Current edition approved July 10, 2003. Published July 2003. Orig
15、inallyapproved in 1993. Last previous edition approved in 1998 as D 543593(1998).2Available from Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.3Annual Book of ASTM Standards, Vol 14.02.1*A Summary of Changes section appears at the end of this standard.Copyright AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.itself assure reliable results. Reliable results depend on manyfactors; Practice D 3740 provides a means of evaluating someof those factors.5. Interferences5.1 Quality control in reagent preparation
17、 is more difficultthan for methods that involve fewer elements and compounds.External contamination is a problem to be anticipated. Rubberis a source of Zn and Cd contamination. Rubber gloves used toremove glassware from an acid bath must be removed forsubsequent rinse procedures. The blank solution
18、 should betested for Na and other elements. Often the superfloc containsNa which should be removed by use of a cation exchange resin.In addition the filter paper should be checked for Na.5.2 The cross contamination from glassware is a seriousproblem. All glassware is soaked in 1 + 1 HNO3for 2 h; rin
19、sedwith distilled water three times followed with rinsing indistilled, deionized water three times. Remove rubber glovesafter first rinsing with distilled water to prevent contaminationwith Zn.5.3 The testing solution should be prepared fresh everyweek. Limited studies indicate that the relative amo
20、unts of thedifferent elements desorbed from soils by DTPA change as theprepared solution ages.5.4 The effect of Ca and other ions on the atomic absorptiondetermination of Cd is significant and requires that an adjust-ment be made. Background correction will eliminate thissource of error.5.5 The TEA
21、(triethanolamine) is used to prevent excessivedissolution of trace metals from high p-H soils. The buffercapacity is not sufficient, however, to prevent a reflection ofsoil acidity on trace element availability in soil.5.6 For some soils the colorimetric determination of phos-phorus is not adequate
22、because of the development of turbiditywith stannous chloride used as the reducing agent or when P isvery near the detection limit of 1 m/L. Other reducing agentsas proposed by Watanabe and Olsen (1)4or the isobutyl alcoholextraction method as proposed for water soluble P (see section12.9) have been
23、 used with limited success on these samples.6. Apparatus6.1 No. 10 Sieve, (U.S. Sieve Series Standard 2 mm)constructed from polyethylene.6.2 Erlenmeyer Flasks, 125-mL capacity with polyethylene-covered rubber stoppers or equivalent.6.3 Rotating Shaker, 150 rpm for 125-mL flasks.6.4 Filter Funnels,11
24、cm.6.5 Filter Paper,515 cm in diameter.6.6 Sample Storage Bottles, 50 mL polyethylene.6.7 pH Meter, with reference and glass electrodes, that isaccurate to 60.02-pH units when standardized against pH 4.01and pH 7.00 buffers.6.8 Precise Automatic Diluter, for use with soil test solu-tions and standar
25、ds 1:50 in SrCl2solution for Mg and Cadeterminations by flame AA or ICP.6.9 Automatic Diluter, accurate, calibrated, for diluting soiltest solutions that are above the range of the working standards.6.10 Atomic Absorption or ICP Spectrometer, equippedwith background correction.6.11 Colorimeter, with
26、 2-cm light-path cells or autoanalyzerfor colorimetric analyses.6.12 Analytical and Top-Loading Balances, accuracy to beverified using Specification E 617 weights.6.13 50-mL Test Tubes, 15-mL Volumetric Pipettes, and 1-mL Measuring Pipettes, for use in P determinations.6.14 50-mL Erlenmeyer Flasks,
27、10-mL Volumetric Pipettes,and 1-mL Measuring Pipettes, for S determination.6.15 Various Beakers, Erlenmeyer flasks, graduated cylin-ders, volumetric pipettes, flasks, storage bottles, magneticheating and stirring unit, refrigerator, and other equipment asrequired for preparing and storing stock solu
28、tions, soil testsolutions, reagents, and standards.6.16 Computer FacilitiesComputer software that is com-patible with IBM-PC and mainframe computers is available toproduce the chemical potentials (negative logarithm of theactivity of respective ions in soil or substrate solutions) isavailable. The s
29、oftware is beneficial in producing output thatprovides decision support for users of this test method.7. Reagents and Materials7.1 Stock SolutionsPrepare the following stock solutionsby dissolving the indicated amount of the pure salt in purewater and diluting to 1 L:Stock Solution Amount of Salt pe
30、r Litre of Solution0.10 M NaCl 5.84 g of NaCl0.25 M KCl 18.64 g of KCl1.00 M MgCl2203.31 g of MgCl26H2O2.00 M CaCl2294.04 g of CaCl22H2O0.010 M KH2PO41.3609 g of KH2PO41000 mg/1 s 5.435 g of K2SO4The use of the above reagents to prepare stock solutionsenables a more constant pH to be achieved when T
31、EA is addedthan the use of compounds considered to provide standards ofmore accurate composition. Since the chloride salts are notsuitable for primary standards, they should be compared withreliable, primary standards and the volumes used are adjustedto meet the required final concentrations.7.2 Pri
32、mary StandardsUse commercial primary standardsfor AA or ICP applications, or both, or prepare 1000-mg/Lstock solutions of Al, Zn, and Cd by dissolving 1.000 g of thepure metal in 50 mL of 1:1 concentrated HCl-water mixtureand diluting to 1 L with pure water. Prepare 1000 mg/L stocksolutions of Mn, F
33、e, Ni, and Cu by dissolving 1.000 g of thepure metal in 1:1 concentrated HNO3-water mixture anddiluting to 1 L with pure water.7.3 DTPA, diethylenetriaminepentaacetic acid.7.4 TEA (0.0275 M TEA)Dissolve 4.101 g of TEA in purewater and dilute to 1 L.7.5 Superfloc-127 Solution, 1 %To 700 mL of pure wa
34、terin a 1-L beaker on a magnetic stirring unit, slowly add 10.0 gof Superfloc-127, a small portion at a time, with continuousstirring and gentle heating. Cover the beaker with a watch glassand allow this solution to stir overnight. Transfer this solutionquantitatively to a 1-L volumetric flask and d
35、ilute to 1 L. Storethis solution in the refrigerator. Dilute 10 mL of the solution to4The boldface numbers in parentheses refer to a list of references at the end ofthis test method.5S if not, adjust theamount of 0.0275 M TEA and pure water used to obtain a pHof 7.3 6 0.05 in a final volume of 50.0
36、mL of soil test solution.Greater precision can be achieved by working with 1-Lvolumes for 20 samples at a time.10.2 Baker Soil Test Equilibration Weigh 5.000 g of soil( 2 mm) into a 125-mL Erlenmeyer flask. Add to the flask theamount of pure water needed to obtain a pH of 7.3 6 0.05 anda final volum
37、e of 50.0 mL with no soil present as determinedin the blank preparation step (see 10.1). Add 5.0 mL of soil testsolution to the flask. Add to the flask the amount of 0.0275 MTEA needed to obtain a pH of 7.3 6 0.05 and a final volumeof 50 mL with no soil present as determined in the blankpreparation
38、step (see 10.1). Stopper the blank and sample flaskswith plastic stoppers and place on a rotating shaker for1hat150 oscillations per minute. Allow the flasks to stand for anadditional 21 to 23 h and filter the samples through filterpaper.510.3 pHDetermine the pH of an aliquot of sample using apH met
39、er and glass and reference electrodes standardizedagainst pH 4.01 and 7.0 buffers.10.4 Elemental AnalysisThe actual analysis of samplewill vary with instrumentation. Na and K may be analyzed byflame emission spectroscopy; for Ca and Mg by Flame AA, thetest solution and standards may need to be dilut
40、ed 1:50 in theSrCl2diluting solution using a precise automatic diluter. BothCa and Mg may be determined by Flame AA. All otherelements may be determined by Flame or Flameless AA, orboth, depending on the concentrations in solution as well as byICP.10.5 Na and KThese two elements are easily determine
41、din the blank and soil test solution samples by flame emissionspectroscopy.10.6 Mg and CaDilute the standards and blank and soiltest solutions samples 1:50 in the SrCl2diluting solution usinga precise automatic diluter. Determine the concentrations ofthese elements in the blank and samples by atomic
42、 absorptionspectrophotometry or by ICP.10.7 Al, Mn, Fe, Ni, Cu, Zn, and Cd Determine theconcentration of these elements in the blank and soil testsolution samples by atomic absorption spectrophotometry.10.8 PAdd 0.5 mL of the ammonium molybdate reagentto 15.00 mL each of blank and soil test solution
43、 samples andeach P standard, and mix. Add 0.3 mL of the stannous chloridereagent, mix, and read the absorbencies on a colorimeter at660-mu using a cell with a 2-cm light path after 6 but before 11min.10.9 Sulfate, SAdd 1 mL of acid seed reagent to 10.00 mLof blank and sample soil test solutions and
44、each S standard,mix, and add 0.5 g of BaCl22H2O crystals (20 to 60 mesh).Let stand for exactly 1 min, mix until the crystals are dissolved,and read the absorbencies on a colorimeter at 420 mu between2 and 8 min using a cell with a 2-cm light path.11. Calculation11.1 Report the results in the units o
45、f the standards for P, K,Ca, and Mg. For the trace elements, report the soil levels arereported (solution levels: x 10.0). If filtrates are diluted, thedilution factor must be applied.11.2 Computer programs are available to perform the itera-tive calculations required to produce values for pH, pK, p
46、Ca,pMg, pFe, pMn, etc. The validity of these conversions has beenverified using numerous samples from research investigationsand thousands of user samples. Use of this computerized expertsystem provides an intensity value, and a desorbed quantityamount for most elements and relative intensity values
47、 for K,Ca, Mg, and H. In addition, data for Total Sorbed Metals by theD5435034U.S. Environmental Protection Agency (EPA) method is in-cluded. See Footnote7for information regarding the computerprogram. The iterative procedure may also be performed usingprogram GEOCHEM-PC (2, 3).7See Footnote 10 for
48、informa-tion regarding the computer program to provide the decisionsupport output from the database for the method.12. Interpretation of Results12.1 For those that do not have access to the computerprograms Table 2 shows interpretation offered with respect toplant growth and food-chain protection.12
49、.2 As indicated in 11.2, the Baker Soil Test8softwareallows the inclusion of total sorbed metals by U.S. EPAMethod 3050A. The above interpretative data represent “smallexchange” calibration values from the existing data for over10 000 samples. The numbers given here do not refer to totalmetal content of a soil sample or the results by U.S. EPAMethod 3050A, and should not be compared with previouslypublished ranges of soil element concentrations. Critical levelsfor the quantity values presented above, based on field re-sponse data, varies with crops and local field cond
