Designation: D 422 - 63 (Reapproved 1972)" AStandard Method forParticle-Size Analysis of Soils1

This standard is issued under the fixed designation 0422. the number immediate!* following the definition indicate* the >ear ofanginal adoption or. m the cue of revision, the year ofiast revision. A number in p«rentheses indicates the year of law reapproval. Asuperscript epsilon Id indicates an editorial chanfe since the last revijion or reapproval.

" NOTE—Section : *as added editonally and jubsequent sections renumoered in July I9W

1. Scop*I. l This method covers the quantitative determination of

the distribution of particle sizes in soils. The distribution ofparticle sizes larger than 75 urn (retained on the No. 200sieve) is determined by sieving, while the distribution ofparticle sizes smaller than 75 urn is determined by asedimentation process, using a hydrometer to secure thenecessary data (Notes I and 2).

SIOTE i—Separation may be made on the No. 4 (4.75-mm). No. 40(425-um). or No. 200 (75-um) sieve instead of the No. 10. For whateversieve used, the sue shall be indicated in the report

NOTE 2—Two types of dispersion devices are provided: (/) ahigh-speed mechanical stirrer. and (2) air dispersion. Extensive invesu-gattons indicate that air-dispersion devices produce a more positivedispersion of plank soils below the 20-um sue and appreciably lessdegradation on all sizes when used with sandy soils. Because of thedefinite advantages favoring air dispersion, its use is recommended. Theresults from the two types of devices differ in magnitude, dependingupon sod type, leading to marked differences in particle sue distribu-tion, especially for sizes finer than 20 urn.

2. Referenced Documents2A ASTM Standards:D 421 Practice for Dry Preparation of Soil Samples for

Particle-Size Analysis and Determination of SoilConstants2

E 11 Specification for Wire-Cloth Sieves for TestingPurposes3

E 100 Specification for ASTM Hydrometers*

3. Apparatus3.1 Balances—\ balance sensitive to 0.01 g for weighing

the material passing a No. 10 (2.00-mm) sieve, and a balancesensitive to 0.1 % of the mas* of the sample to be weighed forweighing the material retained on a No. 10 sieve.

3.2 Stirring Apparatus—Either apparatus A or B may beused.

3.2.1 Apparatus A shall consist of a mechanically oper-ated stirring device in which a suitably mounted electricmotor turns a vertical shaft at a speed of not less than 10 000rpm without load. The shaft shall be equipped with a

1 This mctnod it under the juwdfctio* of ASTM Commute* D-H on Sod andRock and a the direct ropomtefcty of Subcowmmtc D11.03 on Texture,PlaaieJty. and Density Charactcrijua of Soda,

Cuntnt edition approved Nov. 21. 196* Origraaly pubfatad 1935. Replac*D 422-62.2 Annul Book afASTH SroMta*. Vol 04.0ft.1 Annual Joe* of ASTM Suit***, Vol 14.02.

'A™u43o<* of ASTM Slander*, V<* 14,01,

replaceable stirring paddle made of metal, plastic, orrubber, as shown in Fig, 1. The shaft shall be of such ithat the stirring paddle will operate not less than "* m.mm) nor more than I1/: in. (38.1 mm) above the bottcthe dispersion cup. A special dispersion cup conform;either of the designs shown in Fig. 2 shall be provided tcthe sample while it is being dispersed.

3.2.2 Apparatus B shall consist of an air-jet dispecup3 (Note 3) conforming to the general details shown i3 (Notes 4 and 5).

Nort 3—The amount of air required by an air-jet dispersionof the order of 2 fWmia: some small air compressor* are not cap:supplying sufficient air to operate a cup.

NOTT 4—Another air-type dispersion device, known as a disptube developed by Chu and Davidson at Iowa State College, ha;shown to give results equivalent to those secured by the air-jet dispcups. When it is used, soaking of the sample can be done isedimentation cylinder, thus eliminating the need for transferorslurry. When the air-dispersion tube is used, it shall be so mdicathe report.

Non 3—W«er may condense in air lines when not in use,water must be removed, either by using a water trap on the air line.blowing the water out of the line before using any of the idispersion purposes.

3.3 Hydrometer—An ASTM hydrometer, graduateread in either specific gravity of the suspension or gram:litre of suspension, and conforming to the requirementhydrometers 151H or 152H in Specifications E 100. Dirsions of both hydrometers are the same, the scale beinjonly item of difference.

3.4 Sedimentation Cylinder—A glass cylinder essent18 in. (457 mm) in height and 21/: in. (63.5 mm) in diamand marked for a volume of 1000 mL. The inside diarrshall be such that the 1000-mL mark is 36 * 2 cm froirbottom on the inside

3.5 Thermometer—A thermometer accurate to(0.5-Q.

3.6 Sieves—A series of sieves, of square-mesh woven-cloth, conforming to the requirements of Specification £A full set of sieves includes the following (Note 6):

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3-m. (75-mm)2-in. (50-mm)I'-i-in. (3^ 5-mm)I-in. (25.0-mm)".-in. (I9.0-mm)"fin. (9 5-mm)No. * (4.75-mm)

No. 10 a.OO-mm)No. :0 (350-wm(No. *0 (425-t»m)No. 60(250-um)No. !40(I06tin)No. :00(75-nm)

NOTE 6—A set of sieves giving uniform spacing of points for thegraph, a required in Section 17, may be used if desired. This set consistsof the following neves:

3-m. (75-rnm)l"j-m. (37.3-mm)"•-in. (19.0-mm)Vm. (9.5-mm)Vo. 4 (4.75-mm)No. 8 (2.36-mm)

No. l6(l.lS-mn)No. 30 (600->un>No. 50 (MChim)No. I00(l50-tiin)No. :<» (75-tim)

3.7 Water Bath or Constant-Temperature Room—A.water bath or constant-temperature room for maintainingthe soil suspension at a constant temperature during thehydrometer analysis. A satisfactory water tank is an insulatedtank that maintains the temperature of the suspension at aconvenient constant temperature at or near 68T (20*Q.Such a device is illustrated in Fig. 4. In cases where the workis performed in a room at an automatically controlledconstant temperature, the water bath is not necessary.

3.S Beaker—A beaker of 250-raL capacity.3.9 Timing Device—*, watch or clock with a second

hand.

4. Dispersing Ageat4.1 A solution of sodium hejumetaphospoate (sometimes

called sodium metaphosphate) shall be used ia distilled ordemineralized water, at the rate of 40 g of sodiumhexametaphosphate/litre of solution (Note 7).

Son 7—Solutions of this salt if acidic, slowly reven or hydraivz*back to the orthophosphau fora with a resultant decrease ia dispeniv*action. Solutions should bi preptnd frequently (at lea* once • month)or adjusted to pH of I or 9 by mean of sodium carbonatt. BonJeac ininf solutions should havt the date of prepuvtio* marked on

:4.2 All 'water used shall be either distilled or

emineralized water. The water for a hydrometer test snail

h--ZS'dian.——|

in. 1.333

28M

3.7595.2

na a

be brought to the temperature that is expected to prevailduring the hydrometer test For example, if the sedimenta-tion cylinder is to be placed in the water bath, the distilled ordemineralized water to be used shall be brought to thetemperature of the controlled water bath; or, if the sedimen-tation cylinder is used in a room with controlled tempera*ture, the water for the test shall be at the temperature of theroom. The basic temperature for the hydrometer test is 68*F(20'Q, Small variations of temperature do not introducedifferences that are of practical significance and do notprevent the use of corrections derived as prescribed.

5.

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5. Test Sample5.1 Prepare the test sample for mechanical analysis as

outlined in Practice D421. During the preparation proce-dure the sample is divided into two portions. One portioncontains only particles retained on the No. 10 (2.00-mm)sieve while the other portion contains only particles passingthe No. 10 sieve. The mass of air-dried soil selected forpurpose of tests, as prescribed in Practice D421, shall besufficient to yield quantities for mechanical analysis asfollows:

5.1.1 The size of the portion retained on the No. 10 sieveshall depend on the maximum size of particle, according tothe following schedule:

NommaJ Diameter ofLineu Piructa.

in. (mm)'/i (9.5)V. (19.0)

1 (25.4)I1/: (38.1)2 (50.S)3 (76.2)

Approximate MinimumMax of Portion, f

50010002000300040005000

5.1.2 The size of the portion passing the No. 10 sieve shallbe approximately 115 g for sandy soils and approximately .65g for silt and clay soils.

5.2 Provision is made in Section 5 of Practice D421 forweighing of the air-dry soil selected for purpose of tests, theseparation of the soil on the No. 10 sieve by dry-sieving andwashing, and the weighing of the washed and dried fractionretained on the. No» 10 sieve. From these two masses thepercentages retained and pasting the No. 10 sieve can becalculated in accordance with 12.1.

NOTE 8—A cheek oa the ma» values tad tht thorouahnese atpulverization of tht clods may be secured by *ti$fain$ the portionplaint the No. 10 neve and adding this vthie to tht m*j§ of the washedtnd oven-dried portion retained oa tht No. 10 sieve.

SIEVE ANALYSIS OF PORTION RETAINED ON NO. !•<roe-M) SIEVE

6. Proeedwe6.1 Separate the portion retained on the No. 10 (2.00-

mm) sieve into a series of fractions using the 3-in. (75-mra).

re

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3S«

TO. 4 InamtteoJ Water IMt

2-in. (50-mm), IVj-in. (37.5-mra), 1-in. (25.0-mm). '(19.0-mm), ft-in. (9.5-mm), No. 4 (4.75-mm), and Ncsieves, or as many as may be needed depending onsample, or upon the specifications for the material utest

6.2 Conduct the sieving operation by means of a laand vertical motion of the sieve, accompanied by a jajaction in order to keep the sample moving continuouslythe surface of the sieve. In no case turn or manipifragments in the sample through the sieve by hand. Contsieving until not more than 1 mast % of the residue >sieve passes that sieve during 1 min of sieving. N*mechanical sieving is used, test the thoroughness of sieby using the hand method of sieving as described above

6.3 Determine the mast of each fraction on a balconforming to the requirements of 3.1. At the emweighing, the sum of the masses retained on all the s:used should equal dosety the original mass of the quasieved.

89

3R3U0735

0 422HYDROMETER XND SfEVg ANALYSIS OF PORTION

P VSSI.NG THE NO. 10 (2.00-mm) SIEVE

7. Determination of Composite Correction for HydrometerReading

7.1 Equations for percentages of soil remaining in suspen-sion, as given in 14.3, are based on the use of distilled ordemineralized water. A dispersing agent is used in the water,however, and the specific gravity of the resulting liquid isappreciably greater :han that of distilled or demineralizedwater.

7 .1 .1 Both soil hydrometers are calibrated at 68"F (20"C),and variations in temperature from this standard tempera-ture produce inaccuracies in the actual hydrometer readings.The amount of the inaccuracy increases as the variationfrom the standard temperature increases,

7. l .2 Hydrometers are graduated by the manufacturer tobe read at the bottom of the meniscus formed by the liquidon the stem. Since it is not possible to secure readings of soilsuspensions at the bottom of the meniscus, readings must betaken at the top and a correction applied.

7.1.3-The net amount of the corrections for the threeitems enumerated is designated as the composite correction,and may be determined experimentally.

7.2 For convenience, a graph or table of compositecorrections for a series of 1* temperature differences for therange of expected test temperatures may be prepared andused as needed. Measurement of the composite correctionsmay be made at two temperatures spanning the range ofexpected test temperatures, and corrections for the interme-diate temperatures calculated assuming a straight-line rela-lonship between the two observed values.

7.3 Prepare 1000 mL of liquid composed of distilled ordemineralized water and dispersing agent in the sameproportion as will prevail in the sedimentation (hydrometer)test. Place the liquid in a sedimentation cyclinder and thecylinder in the constant-temperature water bath, set for oneof the two temperatures to be used. When the temperature ofthe liquid becomes constant, insert the hydrometer, and,after a short interval to permit the hydrometer to come to thetemperature of the liquid, read the hydrometer at the top ofthe meniscus formed on the stem. For hydrometer 151H thecomposite correction is the difference between this readingand one: for hydrometer 152H it is the difference betweenthe reading and zero. Bring the liquid and the hydrometer tothe other temperature to be used, and secure the compositecorrection as before.

8. Hygroscopic Mobtw*3.1 When the sample is weighed for the hydrometer test

weigh out an auxiliary portion of from 10 to 15 g in a smallmetaJ or glass container, dry the sample to a constant mass inan oven at 230 ± 9*F (110 ± 5'C), and weigh again. Recordthe masses.

9. DispenkM of Soil SunpIt9.1 When the soil is mostly of the clay and silt sizes, weightt a sample of air-dry soil of approximately 50 g. When the

i>oii is mostly sand the sample should be approximately 100g.

9.2 Place the sample m the 250-mL beaker and co'.er *;*.125 mL of sodium hexamctaphospriate solution (40 g,iiStir until the soil is thoroughly wetted. Allow to soak for «least 16 h.

9.3 At the end of the soaking period, disperse the samplefurther, using either stirring apparatus A or 8. If stimngapparatus A is used, transfer the soil - water slurry from thebeaker into the special dispersion cup shown in Fig. 1.washing any residue from the beaker into the cup *tthdistilled or demineralized water (Note 9). Add distilled ordemineralized water, if necessary, so that the cup is morethan half full. Stir for a penod of 1 min.

NOTE 9—A large size syringe is a convenient device for handling thewater m the washing operation. Other devices include the wash-waterbottle and a nose with nozzle connected to a pressurized distilled watertank.

9.4 If stirring apparatus B (Fig. 3) is used, remove theCover cap and connect the cup to a compressed air supply bymeans of a rubber hose. A air gage must be on the linebetween the cup and the control valve. Open the controlvalve so that the gage indicates 1 psi (7 kPa) pressure (Note10). Transfer the soil - water slurry from the beaker to theair-jet dispersion cup by washing with distilled ordemineralized water. Add distilled or demineralized water, ifnecessary, so that the total volume in the cup is 250 mL, butno more.

MOTE 10—The initial air pressure of 1 psi is required to prevent tbesoil • water mixture from entering the air-jet chamber when the matureis transferred to the dispersion cup.

9.5 Place the cover cap on the cup and open the aircontrol valve until the gage pressure is 20 psi (140 kPa).Disperse the soil according to the following schedule:

Plasticity IndexUnder 56 to 20Over 20

Dispersion Penod.mm

51015

Soils containing large percentages of mica need be dispersedfor only 1 min. After the dispersion period, reduce the gagepressure to I psi preparatory to transfer of soil • water slurryto the sedimentation cylinder.

10. HyditMMter Test10.1 Immediately after dispersion, transfer the soil - water

slurry to the glass sedimentation cylinder, and add distilledor demineralized water until the total volume is 1000 mL.

10.2 Using the palm of the hand over the open end of tbecylinder (or a rubber stopper in the open end), turn thecylinder upside down and back for a period of I min tocomplete the agitation of the slurry (Note 11). At the end of1 min set the cylinder in a convenient location and takehydrometer readings at the following intervals of time(measured from the beginning of sedimentation), or as manyas may be needed, depending on the sample or the specifica-tion for the material under test: 2, 5. 15, 30, 60, 250, and1440 min. If the controlled water bath is used, the sedimen-tation cylinder should be placed in the bath between the 2-and 5-min readings.

Nora II—TV number of turn during this minute ihould &*approximately 60, counting tht turn upsxte down and back as two turn*

90

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. „, soil remaining in the bottom of the cylinder dunnf the first fewshould be loosened by vigorous shaking. of the cylinder while it is

n the invened position.10.3 When it is desired to take a hydrometer reading.

carefully insert the hydrometer about 20 to 25 s before thereading is due to approximately the depth it will have whenthe reading is taken. As soon as the reading is taken, carefullyremove the hydrometer and place it with a spinning motion,„ a graduate of clean distilled or demineralized water.

NOTE 12— It is important to remove the hydrometer immediatelyif.tr each reading Readings shall be taken at the top of the meniscusformed by the suspension around the stem, since it is not possible to

readinp at the bottom of the meniscus.

10.4 After each reading, take the temperature of thesuspension by inserting the thermometer into the suspen-sion.

11. Sieve Analysis11.1 After taking the final

the suspension to a No. 200 rwater until the wash water is -.the No. 200 sieve to a suitable230 ± 9*F (110 ± 5'Q andportion retained, using as mar.for the material, or upon the specification of the materialunder test

0422

TASL£ 1 ValuM ofGri

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Mro«ntig> of so* rwnanng r susowisan *

drometer reading, transfer•) sieve and wash with tap

Transfer the material on•vainer, dry in an oven at

.-.e a sieve analysis of the•ves as desired, or required

CALCULATIONS AND REPORT

12. Sieve Analysis VtlM* for the Portico Covscr thai tbtNo. 10 (2.00-mm) Steve

12.1 Calculate the percentage passing the No. 10 sieve bydividing the mass passing the No. 10 sieve by the mass of souoriginally split on the No. 10 sieve, and multiplying the resultby 100. To obtain the mass passing the No. 10 sieve, subtractthe mass retained on the No. 10 sieve from the original mass.

12.2 To secure the total mass of soil passing the No. 4(4.75-mm) sieve, add to the mass of the material passing theNo. 10 sieve the mass of the fraction passing the No. 4 sieveand retained on the No. 10 sieve. To secure the total mass ofsoil passing the >4>in. (9.5-ram) sieve, add to the total mass ofsoil passing the No. 4 sieve, the mass of the fraction passingthe Vi-in. sieve and retained on the No. 4 sieve. For theremaining sieves, continue the calculations in the samemanner.

12.3 To determine the total percentage pissing for eachsieve, divide the total mast passing (see 12.2) by the totalmass of sample and multiply the result by 100.

13. Hygroscopic Mobtwt Comedo* Factor13.1 The hydroscopk moisture correction factor is the

ratio between the mass of the oven-dried sample and theair-dry mass before drying. It is a number less than one,except when there is no hygroscopic moisture.

H. Perceotafts of Soil la Sasptasioa)14.1 Calculate the oven-dry mass of soil used in the

hydrometer analysis by multiplying the sir-dry man by thehygroscopic moisture correction factor.

14.2 Calculate the mass of a total sample represethe mass of soil used in the hydrometer test, by divncoven-dry mass used by the percentage passing the(2.00-mm) sieve, and multiplying the result by 10value is the weight W in the equation for perremaining in suspension.

14.3 The percentage of soil remaining in suspensiolevel at which the hydrometer is measuring the densirsuspension may be calculated as follows (Note 1hydrometer 151H:

?-1(100000/JP) x G/(G - (7,)K* - G,)NOTV 13—The bracketed portion of the equation for hyc

151H is constant for a series of readinp and may be calculatedthen multiplied by tb« portion in the parentheses.For hydrometer 1S2H:

100where:a » correction faction to be applied to the reac

hydrometer 152H. (Values shown on the sccomputed using a specific gravity of 2.65. Corfactors are given in Table 1),

P » percentage of soil remaining in suspension at that which the hydrometer measures the densitysuspension,

R » hydrometer reading with composite correctkplied (Section 7),

W m oven-dry mas* of soil in a total test samplesented by mass of soil dispersed (see :4.2), g,

<7 • specific gravity of the soil particles, andG, - specific gravity of the liquid in which soil partic

suspended. Use numerical value of one icuuuaca m the equation. In th; 5m instan<posiHMe variation produces no womcant effetin the second instance, the composite correctioiis based on a value of one for </,.

15.15.1 The diameter of a partide corresponding

percentage indicated by a given hydrometer reading scalculated according to Stokes' law (Note 14), on th<that a particle of this diameter was at the surfacesuspeasioa at the begtstamcot* sedimentation and hadto the level at which the hydrometer is measuring the cof the suspenaioa. According to Stokes* law:

D - V{30n/9SO(G - 0,)J x L/T

91

f lR300737

J

*here:D *

G0,

diameter of particle, mm.coefficient of viscosity of the suspending medium (inthis case water) in poises (varies with changes intemperature of the suspending medium),distance from the surface of the suspension to thelevel at which the density of the suspension is beingmeasured, cm. (For a given hydrometer and sedimen-tation cylinder, values vary according to the hydrom-eter readings. This distance is known as effectivedepth (Table 2)),interval of time from beginning of sedimentation tothe taking of the reading, mm.specific gravity of soil particles, andspecific gravity (relative density) of suspending me-dium (value may be used as 1.000 for all practicalpurposes).

NOTE 14 — Since Stokes' law considers the terminal velocity of asingle sphere falling in an infinity of liquid, the sizes calculated representthe diameter of spheres that would Tail at the same rate as the soilpanicles.

15.2 For convenience in calculations the above equationmay be written as follows:

Dwhere:K » constant depending on the temperature of the suspen-

sion and the specific gravity of the soil particles. Valuesof K for a range of temperatures and specific gravitiesare given in Table 3. The value of AT does not change fora series of readings constituting a test, while values of Land T do vary.

1 5.3 Values of D may be computed with sufficient accu-racy, using an ordinary 10-in. slide rule.

NOTE 12 — The value of L is divided by ruanftn«^ -and fl -scale*.the square root beinf indicated on the 0-scak. Without ascertaining thevalue of the square root it may be multiplied by K, using either the C- ora-scale.

16. Siert Analysis Values) for Porto* Finer thaa No, 19(2.00-ma) Start

16.1 Calculation of percentages passing the vinous sievesused in sieving the portion of the sample from the hydrom-eter test involves several step*. The first step is to calculatethe mass of the fraction that would have been retained on theNo. 10 sieve had it not ben removed. This mast is equal tothe total percentage retamed oa the No. 10 sieve (100 minustotal percentage pasBosj) times the mass of the total samplerepresented by the mass of soil used (as calculated in 14.2),and the result divided by 100.

16.2 Calculate next the total mast passing the No. 200sieve. Add together the fractional masses retained on ail thesieves, including the No. 10 sieve, and subtract this sum fromthe mass of the total sample (as calculated in 14.2).

16.3 Calculate next the total masses passing each of the^ther sieves, in a manner similar to that given in 12.2.

16.4 Calculate last the total percentages passing by di-viding the total mass passing (as calculated in 16.3) by thetotal mass of sample (as calculated in 14.2), and multiply the-result by 100.

0422

TA8CC 2•4

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ActualHydroffntar

1 0001 0011 0021.0031 0041006

10081 0071 OOt

009.010

011012013014.019

016.017018019020

021.022.023.024.029

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031.032033.034.039038

1.037.1.03S

VahM* o< Sff»rtv« Oeptft Based on Hydronwtf arxt•JMUnemarlnn CyHrxtar <x Spcortod Sac*-*•r 151H

L. an18.319015.815.515.2is.o14.714414213.913.7

13.413.112.912.912.3

12.111811 S11311.0

10.710.910.21009.7

9.49.23.98.83.4

8.178787.37.08.88.96.2

Hytjrom

Actual Effteov*Hyurcmeiaf Otpttt.

adin (.. cni01234S

973910

11 .12131419

1817181920

2122232429

2827282930

16,318.118.015315.815.5

15315.2150148147

14514314214013.8

13.713.513313.213.0

12.912.712.912.412.2

12.011.911.711511 4

(t«r 1S2HActual

f«aong.3132333439

3837383940

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H R 3 Q Q 7 3 8

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10410210 1999,7

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8.83,68.48,38.1

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TA8UE 3 VtK** o« K for UM m ggmtton for Computing DiwMMr of Ptrtefc In

xi* tom»

T«nw«r<turt.•c1617181920

2122232425

2627282930

So«ate Ofwmy of So* PtrteW2.49

0.015100.015110.014920.01474001456

0,014380014210014040013840.01372

0.013570013420.013270013120.01298

2.50001 $050014M0,014670.014490,01431

0014140013970013810013650.01349

0.013340.013190.013040.012900.01276

2.550014410,014620014430,014250.01408

0.013910013740,01358001342001327

0.013120012970.012830.012690.01258

2.600014570.014390.014210.014030.01388

0.013890.013530.013370.013210.01308

0.012910.012770.012840.012490.01238

2650.014380.014170.013990.013820.01388

0,013480.013320.013170.013010.01288

0.012720.012580012440.012300.01217

2.700.014140.013980.013780.013810.01344

0.013280.013120,012970.012820.01287

001 2530.012390.01 2580.012120.01199

2.750.013940,013780013580.013420,01323

0.013090.012940.012790.012840.01249

0.0123S0.012210,012080.011980.01182

2.800013740,011560.013390.13230.01307

0.012910.012780.012610.012480.01232

0,012180.012040.011910.011780,01165

200'0010010,01001

0010,01001001001

001001001001001

of the test results shall be made, plotting the diameter? of theparticles on a logarithmic scale as the abscissa and thepercentages smaller than the corresponding diameters to anarithmetic scale as the ordinate. When the hydrometeranalysis is not made on a portion of the soil, the preparationof the graph is optional, since values may be secured directlyfrom tabulated data.18. Report

1 g. 1 The report shall include the following:18.1.1 Maximum size of panicles,18.1.2 Percentage passing (or retained on) each sieve,

which may be tabulated or presented by plotting on a graph(Note 16),

18.1.3 Description of sand and gravel particles:1 8. 1 .3. 1 Shape — rounded or angular,18.1.3.2 Hardness — hard and durable, soft, or weathered

and friable,18.1.4 Specific gravity, if unusually high or low,18.1.5 Any difficulty in dispersing the fraction passing the

No. 10 (2.00-mm) sieve, indicating any change ia type andamount of dispersing agent, and

18.1.6 The dispersion device used and the length of thedispersion period.

NOTE 16— This tabulation of piph tepiumu tbt fradatioa of thesampk tested. If ptrtcte* Itrfa tbaa ttaott oootaiiMd in the arapferemoved before testing, tiM report dull » «•• pviai the unouat and

18.2 For material teattd for compliance with definitespecifications, the ftMtkm called for ia such specification*shall be reported. TBcftiedoiis smaller thaa the No. 10 sieveshall be read from the graph.

18.3 For materials for which compliance with definitespecifications is not indicated and when the soil is composed

almost entirely of particles passing the No. 4 (4.7!sieve, the results read from the graph may be reporfollows:(/) Gn*L pMU« J-ia. tad reMiiMd oa No. 4 B«W(2) Sud. pout No. 4 am tad retiuMd oa No. 200 or*

(a) Coint Mad. pMatu No. 4 MV« ud retatiMd oeNo. lOira

(6) Mediu* aad, pMBOf No. 10 mt*i ud resaaid onN0.40MVt

(c) Fu* ud. pM»m No. 40 *tvt tad muMd oa No.200 •ret

(J) Sih«a.0.074tt>O.OOJmm(¥) O*y mzt, mute duo 0.003 ma

fVJLWf^ CTMfly ttttm 0,001 ""•

18.4 For materials for which compliance with d<specifications is not indicated and when the soil comaterial retained on the No. 4 sieve sufficient to reqsieve analysis on that portion, the results may be reporfollows (Note 17):

SIEVI ANALYSIS

SicvtSbtPcrUQt

PUBE

J-ia.2-im.

l-ia.Ma,

No. I0(2.00«a)No.No.

HYDROMETER ANALYSIS0.074 am0.005 ••0.001 mm ..

Sort 17— No, I (2.3<-mm) aad No. 50 (300^a)subnmtad for No. 10 and Na 40

7/x A/ntftctfi SocMjf fot rMfiHD1 tntfUMTV or tMt

/to potttontfMf

rtytttof tfw wtffdtx of Any mort

a graph.

If not rrfeh

to 4S7MJ«H /n«r

or flor

f lR300739

Designation: 0 421 - 85

Standard Practice forDry Preparation of Soil Samples for Particle-Size Analysis andDetermination of Soil Constants1

This standard is issued under the fixed designation D •42!: the number immediately following the designation indicates the vear oforiginal adoption or. in the case of revision, the year of last revision. A number m parentheses indicates the year of last rsapprsvil, ^superscript epsilon i<) indicates an editorial change since the last revision or reapproval.

1. Scope1.1 This practice covers the dry preparation of soil sam-

ples as received from the field for panicle-size analysis andthe determination of the soil constants.

1.2 This standard may involve Hazardous materials, oper-ations, and equipment. This standard does not purport toaddress all of the safety problems associated with its use. It isthe responsibility of whoever uses this standard to consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.

2. Referenced Documents2.1 ASTM Standards:D2217 Practice for Wet Preparation of Soil Samples for

Panicle-Size Analysis and Determination of SoilConstants2

E 11 Specification for Wire-Cloth Sieves for TestingPurposes3

3. Significance and Use3.1 This practice can be used to prepare samples for

particle-size and plasticity tests where it is desired to deter-mine test values on air-dried samples, or where it is knownthat air drying does not have an effect on test results relativeto samples prepared in accordance with Practice D 2217.

4. Apparatus4.1 Balance, sensitive to 0.1 g.4.2 Mortar and Rubber-Covered Pestle, suitable for

breaking up the aggregations of soil particles.4.3 Sieves—A series of sieves, of square mesh woven wire

cloth, conforming to Specification E l l . The sieves requiredare as follows:

No. 4(4.75-mm)No. 10 (2.00-mm)No. 40 (423-tim)

4.4 Sampler—A riffle sampler or sample splitter, forquartering the samples.

5. Sampling5.1 Expose the soil sample as received from the field to the

' This practice is under the jurisdiction of ASTM Committee D-18 on Soil andRock and is the direct responsibility of Subcommittee D18.03 on Texture,Plasticity, and Density CtancMnincs of Soils.

Current edition approved July 26. 1985. Published September 198J. OnpiuUypublished as D 421 - 35 T. Last previous edition D42I - 58(1978)".

Annual Book of ASTM Standards. Voi 04.08.1 Annual Book of ASTM Standards. Vol 14.02.

air at room temperature until dried thoroughly. Break up theaggregations thoroughly in the mortar with a rubber-coveredpestle. Select a representative sample of the amount requiredto perform the desired tests by the method of quartering orby the use of a sampler. The amounts of material required toperform the individual tests are as follows:

5.1.1 Panicle-Size Analysis—For the particle-size anal-ysis, material passing a No. 10 (2.00-mm) sieve is required mamounts equal to 115 g of sandy soils and 65 g of either siltor clay soils.

5.1.2 Tests for Soil Constants—For the tests for soilconstants, material passing the No. 40 (425-um) sieve isrequired in total amount of 220 g, allocated as follows:

Test GramsLiquid limitPlastic limnCentnfute moisture equivalentVolumetric shrinkageCheck tests

10015103065

6. Preparation of Test Sample6.1 Select that portion of the air-dried sample selected for

purpose of tests and record the mass as the mass-of the totaltest sample uncorrected for hygroscopic moisture. Separatethe test sample by sieving with a No. 10 (2.00-mm) sieve.Grind that fraction.retained on the No. 10 sieve in a mortarwith a rubber-covered pestle until the aggregations of soilparticles are broken up into the separate grains. Thenseparate the ground soil into two fractions by sieving with aNo. 10 sieve.

6.2 Wash that fraction retained after the second sievingfree of all fine material, dry, and weigh. Record this mass asthe mass of coarse material. Sieve the coarse material, afterbeing washed and dried, on the No. 4 (4.75-mm) sieve ancrecord the mass retained on the No. 4 sieve.

7. Test Sample for Particle-Size Analysis7.1 Thoroughly mix together the fractions passing the No

10 (2.00-mm) sieve in both sieving operations, and by themethod of quartering or the use of a sampler, select a portionweighing approximately 115 g for sandy soils and approxi-mately 65 g for silt and clay soil for particle-size analysis.

8. Test Sample for Soil Constants8.1 Separate the remaining portion of the material passing

the No. 10 (2.00-mm) sieve into two parts by means of a No40 (425-um) sieve. Discard the fraction retained on the No40 sieve. Use the fraction passing the No. 40 sieve for thedetermination of the soil constants.

84

f tR30-07 l *0

0421

Tht Amtrtcm Soowy for Ttstinq tr*i Mtttnta Mm no position ruptcttng trm vt/Mity of my o*tw* rights usirtKt <n connectionwith tny Mm n*nt>or*a in tfia itvatrt. Ustn of this sttfiava in nomsiy tOvma tntt atttrmmttion at trm v«y«3<tv.o/ any sixnptt** eight*, iMttmntttol intnng*r*nt of iucn ngtrti. 4-t nvinty ttmr own rtteonai&lity.

This sttfOtA » mtftet to rtvuion K tny timt Oy tfi» rtsconnblt r*c/>mca/ corrmmtt va must ot rtvttwtd «v«ry livt /Mrs va'I not rtviita. Htm" rtOCforifT or witMrtwn, Your cor^mvut tit invitia vtfmr lor rtvisan of tnu sttnatra or lor sdditionti sttnetraiina sflouia o* ***Mt*0 to ASTM H9*Joo«T«r». Your commtms -Milt rKtnt cvttul coMiairition tr t mttung of tt* wecrisiOMtecnmcu comrmnw*, wfticn you mty antrxi. 'I you fa* Irtot four comments ft«v» not rtcuvta • Itir nttrinq you srtoua mtut yourjifws «mwn to ttit ASTU Comrmntt on Stindva*. 1918 ft«ci St.. PhiltdttpHa. ft* 19103.

mg. asfterand

3

PROCEDURESIN SEDIMENTARY

PETROLOGY

Edited by

ROBERT E. CARVER

University of GeorgiaAthens, Georgia

ENVIRONMENTAL PROTECTION AGENCYANNAPOLIS F;=LD OFFICE

ANNAPOLIS SCIENCE CENTERANNAPOLIS, MARYLAND 21401

WILEY-INTERSCIENCE

A Division of John Wiley & Sons, Inc.New York • London • Sydney • Toronto

A R 3 0 Q 7 l * 2

CHAPTER 3

SIEVE ANALYSIS

ROY L. INGRAM

University of North Carolina, Chapel Hill, North Carolina

The distribution of sizes of sedimentary particles with intcrmediatrdiameters in the range of 1/16 to 16 mm (sand and fine gravel) ismost commonly determined by sieving. In the United States, theUnited States Standard sieves or the Tyler Standard sieves (Table 1)are used by most workers.

TABLE 1 Sieve openings

WentworthScale,mm

16

8

Phi Scale

-4.00-3.75-3.50-3.25-3.00-2.75-2.50-2.25

V^Scale,mm

16.00013.45411.314

9.5148.0006.7275.6574.757

U.S. Standard"

Opening,mm

16.013.511.2

9.518.006.735.664.76

Mesh.

3*4

PermissibleVariation

Averaget %

33333333

Maxi.f %

666666

1010

Tyler6

Mesh

ZVt33V44

49

A R 3 0 G 7 1 4 3

TABLE 1 Sieve openings (Continued)

-«*=ft- :z.'~".A.'

*8B-

u*.w

-P%-! :* >~- -! a*w.-

Jlfe*C

ET-^s-*1"!t*«?:'

•>=AV.»511•.T-"-±^

'ii-«s.*^^.,. -We-.

ifSMa --

Tf^^^_#f

A.S.T.M., 1966, pp. 447-448.'W. S. TylerCo., 1967, p. 10.

i¥*

WentworthScale,mm

4

2

1

1/2

1/4

1/8

1/16

1/32

Phi Scale

-2.00-1.75-1.50-1.25-1.00-0.75-0.50-0.25

0.000.250.500.751.001.251.501.752.002.252.502.753.003.253.503.754.004.254.504.755.00

4V/2~ Scale,mm

4.0003.3642.8282.3782.0001.6821.4141.1891.0000.8410.7070.5950.5000.4200.3540.2970.2500.2100.1770.1490.1250.1050.0880.0740.0620.0530.0440.0370.031

i

U.S. Standard"

Opening,mm

4.003.362.832.382.001.681.411.191.00

0.8410.7070.5950.5000.4200.3540.2970.2500.2100.1770.1490.1250.1050.0880.0740.0630.0530.0440.037

Mesh

5678

101214161820

PermissableVariation

Average± %

33

. 3

Maxi.•f %

Tyier b\Mesh

i10 | 51010

67

3 10 ! 83n

3355

25 53035404550607080

100120140170200230270325400

55555

101010101515

Q

101214

1620

15 j 241515252525

5 ' 255 | 25

28 '3235 ;42 :

486065 ,

6 40 80 '66667

7777

' 40 | 100 j4040406060606060

115150170 ,200 j250 j270 1325 j400 i

i1

nings (Continued)

U.S. Standard" ] .

«g. >

0036,83.38.00.68.41.19.00341707595500.420.354.297.2501.210•.1771.149U25U055.0883.0740.063D.0530.0440.037

Irlesh .-

5678

101214161820253035404550678

10012014017020023C27C

t 32!40(

Perrmsjabie j •Variation

Average± %

33333

, 3335555555555666667

1 7) 7> 7) 7

Maxi.+ % |

10101010

101010101515151515252525252540404040406060606060

Fyler b

Mesh

5 ;6 17 '8 '

i9 '

10 ,12 !1416 i20 .24 128 132354248 .60 16580

100115-150 I170200250270325400

PRELIMINARY TREATMENT 51

Before a sediment is sieved, the individual particles must beseparated from one another. Clay, cementing agents, and soluble saltsmust be removed. Sediments containing cementing agents thatcannot be removed without altering the individual particles cannotbe analyzed by sieving (e.g., most silica-cemented sandstone or mostcarbonate-cemented clastic limestones).

For sieve analysis, most sediments can be placed in one of threecategories: (A) sediment contains clay and cementing agents, (B)sediment contains clay, but does not need to be freed of cementingagents or pigments, and (C) sediment contains no clay, cementingagents, or soluble salts. All the steps in the procedure below shouldbe done for Type A sediments. Only those steps marked with a Qneed be done for Type B sediments. Only those steps marked with aA need be done for Type C sediments.

As the purposes and requirements of sieve analysis and the natureof sediments are variable, however, au o: the- steps should beconsidered and decisions made on each sample or suite of samples asto which steps will be performed or eliminated.

PRELIMINARY TREATMENT

D A 1. Dry sediment in air or in a 40°C oven.At higher temperatures any clay present may be baked into a

bricklike substance, thus making dispersal of the clay difficult.Temperature-sensitive minerals such as halloysite will also be alteredat higher temperatures.

Q A 2. Break all clumps. Mash with fingers; use wooden or rubberpestle in a mortar; or use a wooden rolling pin. Use enough force toseparate the grains, but avoid breaking individual grains.

D A 3. Mix sediment thoroughly and split to get the desiredweight of sample. The exact size of sample that should be useddepends on several factors: the size and sorting of the sediment, theshape and roundness of the grains, the number of screens that will beused, the shaking time. Consequently exact weights cannot bespecified. As a preliminary guide the following approximate weightsa« suggested: fine gravel—500 gm; coarse sand—200 gm; medium

32 SIEVE ANALYSIS

sand-100 gm; fine sand-25 to 50 gm. About 15 gm (range of 5 to25 gm) of material finer than 1/16 mm is needed if a pipette orhydrometer analysis is to be made. Another split may be necessarvfor the analysis of this fine material. Any of several alternateprocedures may be used.

Coning and Quartering

Pour the sample on a flat surface so as to form a cone (Fig. 1). Usea straight edge and separate the cone into four quarters. Push asidetwo of the alternate quarters. Mix the remaining two quarters andform another cone. Continue the quartering process until the desiredsize sample is obtained. Do not attempt to get a sample of an exactsize. For example, if a 100 gm sample is wanted, a sample within therange of 75 to 125 gm will usually be acceptable.

Fif. 1 Splitting sample by coning and quartering. (After W. S. Tyler Co., 1967.p. 13)

JALYS1S

gm. About 15 gm (range of 5 to16 mm is needed if a pipette or:. Another split may be necessaryitcrial. Any of several alternate

e so as to form a cone (Fig. 1). Useone into four quarters. Push asideix the remaining two quarters andquartering process until the desiredttempt to get a sample of an exactnple is wanted, a sample within thebe acceptable.

PRELIMINARY TREATMENT 53Mechanical Sample Splitters

A variety of types of mechanical sample splitters are available; themost common type is shown in Fig. 2. Pouring the sample throughthe splitter will divide the sample in half. Replace one of the panscontaining one-half of the sample with a clean pan, and pour this halfthrough the splitter again. The clean pan will then receive one-fourthof the original sample. Repeat as needed to get the desired weight ofsample.

Overloaded sieves do not separate efficiently. If the weight on anyscreen exceeds the values shown in Table 2, a smaller size split of thesample should be obtained and re-sieved.

D A 4. Weigh the split sample to the nearest 0.01 gm. Record onform for recording sieve analysis, line 6 (Fig. 3).

Some workers use a small (about 10 gm) split of the sample anddetermine the moisture content of the sample by heating in a 110°C

I quartering. (After W. S. Tyjer Co.. 1967. Fig. 2 Sample splitter (From W. S. Tyler Co., 1967, p. 13)

f lR300.7k '7"

54 SIEVE ANALYSIS

oven for 2 hours and cooling in a desiccator. The weight of thesample to be sieved is then corrected for the moisture content. Thissupposedly more accurate method, however, may well result in a lessprecise analysis because of the rapid absorption of moisture by thesample between the desiccator and the balance (Folk, 1968, p. 38).

TABLE 2 Maximum sieve loads on 8-in. diameter sieves.Based on the conservative interpretation, extrapolation,

and combination of the works of Shergold (1946), Whitby (1958),and McManus( 1965).

Sieve Size Adjacent Sieves Differ Bv

Phi-2.00-1.75-1.50-1.25-1.00-0.75-0.50-0.250.000.250.500.751.001.251.501.752.002.252.502.753.003.293.503.754.004.254.504.755.00

ram 1/4 Phi4 40 g

363431

2 28262422

1 20181716

1/2 14131211

1/4 10983

1/8 7665

1/16 5544

1/32 3

1/2 Phi 1 Phi80 g 160 g

, 68

56 110

48

40 80

34

28 60

24

20 40

17

15

!2

10 20

8

7 15

VSIS

i desiccator. The weight of theI for the moisture content. This

wever, may well result in a less. absorption of moisture by thethe balance (Folk, 1968, p. 38).

s on 8-in. diameter sieves,pretation, extrapolation,ergold (1946), Whitby (1958),(1965).______________

:ent Sieves Differ By1/2 Phi 1 Phi

80 g

68

56

48

'0

34

28

24

20

17

15

12

10

8

7

160 g

110

80

60

40

20

15

REMOVAL OF SUBSTANCES THAT INTERFERE WITH DISPERSAL 55

When using the nonmoisture correction technique, all materialsshould remain exposed to the air until equilibrium is reached withthe moisture in the air.

REMOVAL OF SUBSTANCES THAT INTERFEREWITH DISPERSAL

The decision as to whether or not to remove carbonates, organicmatter, iron oxides, or soluble salts depends on the purpose of theanalysis and the composition of the sample. '

SIZE ANALYSIS BY SIEVING

1. Sample No.. .2. Analyst, .3. Date. _4. Summarvof Preliminary Treatment, Dispersal, etc..

.; Concentration. .; Vol..5. Dispersant added ______6. Weight o~f untreated sample _______________________7. Weight of sample after removal of carbonates, organic matter, irono xides_______________________________________

8. SiPhi

eve Opmm

emngMesh

Grade Size Wt.Retai-itd Weight % Cumulative %

Fig. 3 Form for recording sieve analysis.

56 SIEVE ANALYSIS

I!

Removal of CarbonatesThis procedure is not recommended if mineralogical studies are

be made on the sample.5. Place the sample in a 250- to 600-ml beaker. Add 25 ml distill

or deionized water and stir.6. Add 10% HC1 slowly until effervescence stops.If carbonate material is abundant, the addition of 10% HCI v

eventually result in a very large volume of liquid. When the beake:nearly full, concentrated acid may be added very slowly or the excliquid may be decanted or siphoned off.

7. Heat to 80 to 90°C. Add HCI until effervescence stops. A m.exact procedure is to add HCI until a pH of 3.5 to 4 is reached ;maintained. The pH can be checked by using: (a) a pH meter, 'bpH indicator solution on a spot test plate (e.g., brom phenol bindicator solution), (c) pH paper. Methyl orange indicator pawhich changes from yellow in a neutral solution to orange at pHto 4.4 and red below pH 3.1 is recommended.

8. If much carbonate material is present, the dissolved calciions will interfere with the dispersal of the sample, will hinderremoval of organic matter with the HjOj treatment, andprecipitate as calcium oxalate in the iron removal treatment. Wsample with very dilute HCI (about 0.1%). Repeat washing twcthree times. The liquid can be tested for calcium by making a sramount of the liquid in a test tube alkaline to litmus paper vammonium oxalate. A white precipitate of calcium oxalate will ftif much calcium is present.

Washing can be done in several ways: (a) transfer sediment toor more centrifuge tubes using the wash solution in a wash bottlea rubber policeman. Stir thoroughly. A rubber stopper smaller tthe inside of the centrifuge tube attached to a glass stirringmakes a good stirrer (Fig. 4). Centrifuge and decant liquid abovesediment cake, (b) If the material is essentially all sand or coarselet the sediment settle in the beaker and decant or siphon offliquid, (c) Place porcelain filter candle in beaker and remove liewith suction or vacuum pump (Fig. 5). The sediment that cakethe filter is removed by applying back pressure.

f lR300750

YSIS

d if mineralogical studies are to

0-ml beaker. Add 25 ml distilled

vescence stops., the addition of 10% HC1 willline of liquid. When the beaker is: added very slowly or the excessoff.until effervescence stops. A more. a pH of 3.5 to 4 is reached andi by using: (a) a pH meter, (b) a;st plate (e.g., brom phenol blue

Methyl orange indicator paper,utral solution to orange at pH 3.1•nm< 'd,is present, the dissolved calciumial of the sample, will hinder thethe HjOj treatment, and will

.he iron removal treatment. Washut 0.1%). Repeat washing two ored for calcium by making a smallibe alkaline to litmus paper withpitate of calcium oxalate will form

.vays: (a) transfer sediment to onewash solution in a wash bottle anddy. A rubber stopper smaller thane attached to a glass stirring rodtrifuge and decant liquid above theis essentially all sand or coarse silt,

iker and decant or siphon off theandle in beaker and remove liquidig. 5). The sediment that cakes ontack pressure.

GUu rod

Fig. 4 Stirrer for use incentrifuge tubes, grad-uate cylinders, and 10on.

?if. 5 Filtration* using porcelain filter. (From Krumbein and Pettijohn, 1938,P-67)

57

58 SIEVE ANALYSIS

&R-4»fc

rinH

-.5fVf»W -£!&*"

^.^:**^^"

Removal of Organic Matter (Jackson, Whitting, and Pennington.,1949, pp. 77-81)

This procedure will seldom remove all the organic matter, but isstill very helpful in dispersing the sediment. This procedure may bestopped after any step, when most of the organic matter has beenremoved.

D 9. If little organic matter is present, place the sample in 3.400-ml beaker and add 100 ml of 6% H2O2 slowly and with constantstirring. Cover and heat to 40°C for 1 hour. Bring to a brief boil atthe end of the heating period to remove excess H2O2 •

10. If much organic material is present, do the following:(a) Remove excess clear liquid by decantation after gravity

settling or centrifuging.(b) Add 30% H2Oj very slowly while stirring until frothing

stops. Do not let sample froth over. Avoid contact of skinwith 30% H2 O2 , for this reagent will cause burns.

(c) Heat to 40°C on a hot plate for 10 minutes. It may benecessary to remove sample from heat and to cool with a

.jet of cold water to prevent frothing over. Use a largerbeaker if samples consistently froth over.

(d) Evaporate to a thin paste but not to dryness. Add 10 to30 ml 30% H2O2 , cover with watch glass, and digest at 40to 60°C for 1 to 12 hours. Repeat until organic matter isremoved.

(e) Bring to a brief boil to remove excess H2 O2 .

Removal of Iron Oxides (Leith, 1950, pp. 174-176)11. Place sample in a 400-ml beaker and add water to make a

volume of about 300 ml.12. Place aluminum (a cylinder of sheet aluminum is preferable.

but any form of recoverable aluminum will do) in beaker.13. Add 15 gm oxalic acid (powder or concentrated solution

containing 15 gm) and boil gently for 10 to 20 minutes. Add moreoxalic acid as needed to remove all the iron.

Removal of Soluble Salts14. Remove excess liquid by decanting after centrifuging or

gravity settling, or by filtering. If the liquid is turbid with suspended

SALYSIS

:kson, Whitting, and Pennington.

ove all the organic matter, but issediment. This procedure may be>t of the organic matter has been

i present, place the sample in a% H2O2 slowly and with constantDr 1 hour. Bring to a brief boil atnove excess H 2O 2 .resent, do the following:quid by decantation after gravity

lowly while stirring until frothing: froth over. Avoid contact of skin; reagent will cause burns,

plate for 10 minutes. It may beiple fr~rn heat and to cool with a•even,, othing over. Use a largerently froth over.:te but not to dryness. Add 10 tor with watch glass, and digest at 40urs. Repeat until organic matter is

emove excess H2 O2 •

1950, pp. 174-176)beaker and add water to make a

r of sheet aluminum is preferable,num will do) in beaker,powder or concentrated solution

v for 10 to 20 minutes. Add more1 the iron.

decanting after centrifuging orthe liquid is turbid with suspended

DISPERSAL 59

clay, digest by placing tube or beaker containing the sediment in aboiling water bath to cause flocculation. For suspensions that resistflocculation, add a very- small amount of NaCl.

15. Wash (see step 8) two to five times. Stop if clay starts todisperse. Recent marine sediments should be washed until chloride-free. A drop of 4% silver nitrate in the filtrate will form a whiteprecipitate of silver chloride if chlorine is present.

If a large number of marine samples are to be processed, removal ofthe salts by dialysis is recommended (Miiller, 1967, pp. 33—34) sothat many samples may be processed at once. Place each sample in adialyzer bag and place in a large container filled with water. Thewater in the container should be changed frequently. Fastest resultsare obtained if water flows continuously through the container. Theprocess may take several days for marine clays.

•

Drying and Weighing

16. Dry sample in air or in a- 40°C oven. If no clay is present, thedrying may be done in a 100°C oven. The drying process will bespeeded up if the sample is spread out in a thin layer on a large watchglass, aluminum plate, and so on.

17. Let sample come to equilibrium with the moisture in the roomair (about 1 hour).

18. Weigh sample to nearest 0.01 gm and record on line 7 of Fig.3. This is the weight that is used in calculating percentages aftersieving.

DISPERSAL

If the sample contains no clay and. little silt, the dispersalprocedure may be eliminated. For accurate work, however, thesample should be dispersed, for sand grains often have an almostinvisible coating of clay particles. The dispersal procedure shouldresult in the replacement of all exchangeable cations held by the claywith sodium ions and in the removal of other ions that hinderdispersal.

D 19. Place sample in a 400-ml beaker and add 200 ml of distilledor deionized water.

f l R 3 0 0 7 5 3

60 SIEVE ANALYSIS

D 20. Add a volume of 10% Calgon equal to we, where w is theweight of the sample and c is the estimated percent of clay. In otherwords, add 1 ml of 10% Calgon for each gram of estimated clay. If indoubt, overestimate the percent clay. Record on line 5 in Fig. 3.Until a person has some experience in estimating the percentage ofclay, it is perhaps advisable to follow the recommendations of ASTMSpecification D422-63 (1963, p. 208) and add a constant 50 ml of10% Calgon to each sample.

The amount of and the kind of dispersing agent that will give thebest dispersal depend on the amount of clay, the type of claymineral, and the kinds of adsorbed ions. Usually this information willnot be known. The work of Rolfe, Miller, and McQueen (1960) hasshown that some clays need an amount of dispersing agent equal to10% by weight of the amount of clay. For best dispersal theoptimum amount of dispersing agent to add must be determined byexperimentation for either too little or too much will decrease theamount of dispersal. Fortunately, the dispersal curve for Calgon has arather broad, flat top, so. that not using the optimum amount ofdispersing agent will not introduce a very large error.

Dispersing agents commonly used are sodium hexamctaphosphate(Calgon), sodium tripolyphosphate, tetrasodium phosphate, sodiumcarbonate, sodium hydroxide, sodium oxalate, sodium silicate, andammonia. Ten percent solutions of any of these may be used, butCalgon is usually considered the best overall dispersing agent. Calgonhas the added advantage of complexing calcium ions that may be insolution rather than forming insoluble calcium precipitates, whichthe carbonate and oxalate dispersing reagents do.

D 21. Let soak overnight. Then pour into the dispersion cup of amechanical analysis stirrer (Fig. 6) and mix for 1 to 5 minutes. Afaster but less efficient alternate is to boil the suspension gently for15 minutes and then to mix in the stirrer for 5 minutes (sand) to 30minutes (clay).

For samples that resist dispersal, centrifuge, decant clear liquid,and repeat steps 20 and 21. The decanted liquid will often containthe substances that interfered with dispersal so that the clay willdisperse merely by shaking it in distilled or deionized water.

LYSIS

gon equal to we, where w is thetimated percent of clay. In other.'ach gram of estimated clay. If inay. Record on line 5 in Fig. 3.: in estimating the percentage of-v the recommendations of ASTM08) and add a constant 50 ml of

lispersing agent that will give thelount of clay, the type of clay:ms. Usually this information willMiller, and McQueen (1960) has

ount of dispersing agent equal toof clay. For best dispersal thent to add must be determined bytie or too much will decrease thehe dispersal curve for Calgon has an using the optimum amount ofa very large error.:d are sodium hexametaphosphatec, tet >dium phosphate, sodiumlium oxalate, sodium silicate, andof any of these may be used, but>cst overall dispersing agent. Calgonlexing calcium ions that may be inoluble calcium precipitates, whichng reagents do.i pour into the dispersion cup of a5) and mix for 1 to 5 minutes. Ais to boil the suspension gently forhe stirrer for 5 minutes (sand) to 30

sal, centrifuge, decant clear liquid,; decanted liquid will often contain.vith dispersal so that the clay will, is tilled or deionized water.

SEPARATION OF FRACTION TO BE SIEVED 61

Fig. 6 Mechanical analysis itirrer.

SEPARATION OF FRACTION TO BE SIEVED

The fraction to be sieved may be separated by wet sieving (steps22-24) or by decantation (steps 25-28).

Separation by Wet SievingD 22. Pour the dispersed sediment onto a wet 1/16-mm screen set

over a large' runnel. Make certain that all the sediment has beenwashed from the dispersion cup (use a wash bottle). If the silt andclay are to be analyzed, collect the sediment that passes through thescreen in a 1000-ml cylinder.

O 23. Wash the residue on the screen with distilled or demineral-ized water from a wash bottle. Continue washing until nearly all fines

f l R 3 0 0 7 5 5

62 SIEVE ANALYSIS

are washed through screen. Do not exceed 1000 ml if the finefraction is to be analyzed.

D 24. Dry sand on sieve in a 110°C oven, over a hot plate or underan infrared drying lamp. The sieve may be damaged if heated higherthan 150°C.

Often the 1/16 mm screens need to be made available for otheruses as soon as possible. An alternate drying procedure is to use awash bottle and transfer the sand on the sieve into a large funnellined with rapid-filtering filter paper. The sand is then dried on thefilter paper.

Let sample remain heated or store in a desiccator until ready forsieving.

Separation by Decantation25. Pour the dispersed sample into one or more test tubes.

centrifuge tubes, high-form beakers, or small graduated cylinders.Stir well and let settle for the time required for a 1/32 mm particleto settle to the bottom (see Table 3).

TABLE 3 Time for quartz particle to settle 10 cm in water"

Diameter TemperaturePhi44.55

mm1/16

1/32

000

.062

.044

.031

15°C0 min12

32 sec5

10

20s C0 min01

29 sec5755

250 min01

°C25 sec5142

300 min01

=C23 sec4531

a For a distance of settling(s) other than 10 cm, multiply above times by j/10.

26. Carefully decant liquid above sediment cake. Collect liquid ina 1000-ml cylinder if the fines are to be analyzed.

27. Transfer .all sediment to one container. Add distilled ordemineralized water (usually 10 cm above the sediment cake). Stirwell. Let settle for required time (see Table 3) and decant. Repeatuntil decanted liquid is clear, usually about five times. After the firstthree settlings, dispersal is often helped by using water adjusted topH 10 with the dispersing agent (about 1 ml of 10% dispersingsolution per liter of water to give a 0.01% solution).

28. Dry sample in a 110°C oven, over a hot plate or under aninfrared drying lamp. The drying time will be decreased greatly if the

HR300756

SIS

exceed 1000 ml if the fine

Dven, over a hot plate or undery be damaged if heated higher

3 be made available for other• drying procedure is to use a

the sieve into a large funnelThe sand is then dried on the

in a desiccator until ready for

into one or more test tubes,or small graduated cylinders.

squired for a 1/32 mm particle

SIEVE ANALYSIS

sediment is transferred to a large funnel lined with rapid-filteringfilter paper and the sediment dried on the filter paper. Let sedimentremain heated or store in a desiccator until ready for sieving.

SIEVE ANALYSIS

For efficient sieving the sample must be composed of individualdry grains. According to Bartel (1960, in Miiller, 1967, p. 65) with asurface moisture as little as 1%, adhesion forces exist that canovercome the weight of grains smaller than 1 mm.

D A 29. Build up a nest of clean screens for subdivisions desiredwith the coarsest screen on top. Half-height screens will allow a largernumber of screens to be used at one time. A lid should be put on thetop and a pan at the bottom of the nest of sieves.

D A 30. Pour dry sediment onto top screen in nest. Make certainthat all sediment passes the top screen.

« to se 10 cm in water

Temperature_________25°C 30 C

29 sec 0 min57 055 1

25 sec5142

0 min01

23 sec4531

cm, multiply above times by j/10.

sediment cake. Collect liquid inbe analyzed.ie container. Add distilled or\ above the sedrr.er.t cake). Stirsee Table 3) and decant. Repeatv- about five times. After the first:lped by using water adjusted to(about 1 ml of 10% dispersing',01% solution).n, over a hot plate or under anne will be decreased greatly if the Fig. 7 Ro-Tap mechankai shaker. (From W. S. Tyier Co., 1967, p. 15)

f l R 3 G 0 7 5 7

64 SIEVE ANALYSIS

D A 31. Place in Ro-Tap mechanical shaker (Fig. 7) and shake for10 minutes.

Most workers have accepted 10 minutes of shaking in a Ro-Tap asan arbitrary standard, although some use 15 minutes. A long shakingtime will result in more material passing through each screen(Whitby, 1958, p. 4); but because of inaccuracies in sieves (Table 1Ulong shaking times result primarily in the near mesh-size particlespassing through the too-large holes (Miiller, 1967, p. 75). The bestsieving is one in which the sum total p{ the inaccuracies caused bythe fines not passing through a sieve and by the coarse materialpassing through oversize holes is the smallest.

D A 32. Empty each sieve onto a large (15 x 15 in.) sheet ofpaper. The removal of sand is helped by striking the rim of the sievewith either the palm of the hand or the wooden handle of a screenbrush along the general direction of the diagonals of the wire meshand brushing the bottom of the sieve with a sieve brush. Use a softbrass wire sieve brush on sieves coarser than 100 mesh. For sievesfiner than 100 mesh, use only a nylon bristle sieve brush. Be carefulnot to push wires apart.

D 33. Add the fines passing the bottom (1/16 mm or smaller)screen to the cylinder containing the fines in step 22 or 26.

OA34. Weigh each fraction to the nearest 0.01 gm. Makecalculations as shown on Fig. 3. If determined, the weight shown online 7 will be used as the sample weight in determining percentages.

CARE OF SIEVES

O A 35. After each use all sieves should be carefully cleaned (seestep 32) and stored.

36. Occasionally, more thorough cleaning of the screens may beneeded (W. S. Tyler Co., 1967, p. 19).

(a) Wash sieves in warm soapy water using the special sievenylon and brass sieve brushes.

(b) If this treatment fails to remove most of the lodgedparticles,, dip sieves in a boiling^5% solution of acetic acidand then use sieve brushes on sieves. Wash sieves thor-oughly to remove the acid. - ; ~ ~ a_.

in**- ' O

• - • • • . oCO

" . • -• en.

ALYSIS

nical shaker (Fig. 7) and shake for

minutes of shaking in a Ro-Tap asme use 15 minutes. A long shakingrial passing through each screen• of inaccuracies in sieves (Table 1),ily in the near mesh-size particles,es (Muller, 1967, p. 75). The besttotal of the inaccuracies caused by

sieve and by the coarse materialic smallest.to a large (15 x 15 in.) sheet oftped by striking the rim of the sieve1 or the wooden handle of a screeni of the diagonals of the wire meshsieve with a sieve brush. Use a softcoarser than 100 mesh. For sievesnylon bristle sieve brush. Be careful

the bo»rom (1/16 mm or smaller)the fi. in step 22 or 26.

to the nearest 0.01 gm. MakeIf determined, the weight shown on

: weight in determining percentages.

ves should be carefully cleaned (see

ugh cleaning of the screens may be,. 19).soapy water using the special sieve

brushes.ills to remove most of the lodgedi a boiling 5% solution of acetic acidbrushes on sieves. Wash sieves thor-acid.

TESTING SIEVES 65

ACCURACY OF SIEVES

Three different types of sieves may be purchased. Most commer-cially available sieves are manufactured to meet the tolerancesestablished under ASTM Specifications £11-61. (See Table 1.) TheNational Bureau of Standards will, for a fee, check a set of sieves andwill certify them if they meet ASTM specifications. The manufac-turer selects matched sieves to give results for a given sample that arecomparable to those obtained from the manufacturer's Master Sieves.Matched sieves are the most accurate available.

TESTING SIEVES

Sieves may be checked for accuracy in several different ways(ASTM, 1966, and W. S. Tyler Co., 1967, p. 39).

Use of Standard SamplesThe use of calibrated glass spheres is recommended for checking

and determining the effective sieve openings. Calibrated glass spheresmay be obtained from the Supply Division, National Bureau ofStandards, Washington, D. C. Three standard samples are nowavailable at $9.50 each: No. 1017, 0.050 to 0.230 mm; No. 1018,0.210 to 0.980 mm; and No. 1019, 0.90 to 2.55 mm. Instructionsare provided for using the glass spheres in calibrating sieves.

For routine checking of sieves each laboratory should maintain itsown standard sample. A set of sieves should be checked periodicallywith a standard size split of the standard- sampfc to see if the setcontinues to zrve^he same results, A new set of sieves- can also be

Slfca^ * * . ••

checked against the standard to see if the sets give comparableresults. If they do not, calibration factors can be calculated for eachsieve that will make the results comparable.

Measurement of OpeningsSeveral methods of measuring openings are given in ASTM

Specification £11-61. One method is to use a microscope and measurethe openings. Six nonoveriapping fields of view are selected. In each

S R 3 0 0 7 5 9

66 SIEVE ANALYSIS

field measure at least 50 openings perpendicular to the wires, withthe openings being'located in a diagonal direction across the field(Fig. 8). The openings in three of the fields should be measured atright angles to those in the ocher three fields. Tabulate the resultsand check against Table 1.

REFERENCES

American Society for Testing Materials, 1963, Grain size analysis ofsoils, D422-63, pp. 203-214, in 1967 Book of ASTM Stand-ards, Pt. 11, Philadelphia.

___, 1966, Sieves for testing purposes, Ell-61, pp. 446—452, in1966 Book of ASTM Standards, Pt. 30, Philadelphia.

Folk, R. L., 1968, Petrology of sedimentary rocks, Hemphills,Austin, Texas, 170 pp.

Jackson, M. L., L. D. Whitting, and R. P. Pennington, 1949,

x\

FSf. ft Testing neve* by micrmcopk measurement of opening* located alongdiagonalrof opening*.

H R 3 Q Q 7 6 Q

\LYSIS

jerpendicular to the wires, withgonal direction across the fieldhe fields should be measured athree fields. Tabulate the results

ials, 1963, Grain size analysis ofin 1967 Book of ASTM Stand-

rposes, Ell-61, pp. 446—452, inPt. 30, Philadelphia,sedimentary rocks, Hemphills,

. and R. P. Pennington, 1949,

tevurcment of openings located along

REFERENCES 67

Segregation procedures for mineralogical analysis of soils, SoilSci. Soc. Am. Proc., 14, 77-81.

Krumbein, W. C. and F. J. Pettijohn, 1938, Manual of sedimentarypetrology, Appleton-Cemury-Crofts, 549 pp.

Leith, C. J., 1950, Removal of iron oxide coatings from mineralgrains,/. Sed. Pet.. 20, 174-179.

McManus, D. A., 1965, A study of maximum load for small diameterscreens,/. Sed. Pet., 35, 792-796.

Mliller, German, 1967, Sedimentary petrology, Part I, Methods insedimentary petrology, translated by Hans-UIrich Schmincke,Hafner Publishing Co., 283 pp.

Rolfe, B. N., R. F. Miller, and I. S. McQuee 360, Dispersioncharacteristics of montmorillonite, kaolinitc ..id illite clays inwaters of varying quality and their contr;i with phosphatedispersants, U.S. Ceol. Surv. P.P. 334-G, pp. 229-273.

Shergold, F. A., 1946, The effect of sieving loading on the results ofsieve analysis of natural sands, Soc. Chemical Industry Trans., 65,245-249.

Whitby, K. T., 1958, The mechanics of fine sieving, pp. 3-24, inSymposium on particle size measurement, ASTM Spec. Publ. No.235, Philadelphia, 303 pp.

W. S. Tyler Co., 1967, Testing sieves and their uses (Handbook 53),W. S. Tyler Co., Mentor, Ohio, 48 pp.

f l R 3 0 0 7 6 i .-..,-r-r

(TIG & ALLARDICEi glycerol and ethylene

ir the identification of

• s for X-ray diffraction

idards for quantitative12:400-406.ondon.

13 Bulk Density1

G. R. BLAKEUniversity of MinnesotaSt. Paul, Minnesota

K. H. HARTGEUniversity of HanoverHanover, Federal Republic of Germany

13-1 GENERAL INTRODUCTION

Soil bulk density, ps is the ratio of the mass of dry solids to the bulkvolume of the soil. The bulk volume includes the volume of the solidsand of the pore space. The mass is determined after drying to constantweight at 105 °C, and the volume is that of the sample as taken in thefield.

Bulk density is a widely used value. It is needed for converting waterpercentage by weight to content by volume, for calculating porosity andvoid ratio when the particle density is known, and for estimating theweight of a volume of soil too large to weigh conveniently, such as theweight of a furrow slice or an acre-foot

Bulk density is not an invariant quantity for a given soil. It varieswith structural condition of the soil, particularly that related to packing.For this reason it is often used as a measure of soil structure. In swellingsoils it varies with the water content (Hartge, 1965, 1968). In such soils,the bulk density obtained should be accompanied by the water contentof the soil at the time of sampling.

The determination usually consists of weighing and drying a soilsample, the volume of which is known (core method) or must be deter-mined (clod method and excavation method). These methods differ inthe way the soil sample is obtained and its volume determined. A differentprinciple is employed with the radiation method. Transmitted or scat-tered gamma radiation is measured; and with suitable calibration, thedensity of the combined gaseous-liquid-solid components of a soil massis determined. Correction is thflp necessary to remove the componentsof density attributable to liquidlind gas. that are present The radiationmethod is an. in. situ method.

'Paper no. 11718 of the Scientific Journal Series, Minnesota=*|ricultual ExperimentStation, St Paul. MN.Copyright 1986 O American Society of Atronomy—Sod Seine* Society of America. 677South Sefot Road Madison. WI 53711, USA. Methods of Soil Analysis. Pan I. Physicaland Mintnlogical Methods—Agronomy Mooofnpo no. 9 (2nd Edition)

343

J6 R 3 0 0 7 6 2 il

bituminous and gravelly matenal. More recently the excavation methodhas found use in ullage research, or where surface soil is often too looseto allow core sampling, or where abundant stones preclude the use ofcore samplers. Radiation methods have been used since the 1950s, par-ticularly in soil engineering.

Bulk density is expressed in SI units or units derived from them. Themost straightforward would be kg m"3. However, derived units such astons m~3, g cm"3, or Mg m~3, which are numerically equal to each other,may be more convenient, as they give values for soils which vary fromabout 1.2 to 1.7 (rather than from 1200 to 1700, as when units of kg m"3

are used). Obsolete terms such as "volume weight" (weight • volume"1)and "bulk specific gravity" or "apparent specific gravity" are sometimesfound in the older literature and in some foreign language literature.Specific gravity terms are relative densities, i.e. density of a substancewith respect to water at 4°C, and are nearly equal numerically to bulkdensity. At standard gravitation (g - 9.8 m s~2), kilogram weight andkilogram mass are equal, and under this condition "volume weight" isnumerically equal to bulk density. In many engineering and commercialapplications, bulk density is expressed in Ib ft"3, which one may convertto g cm"3 by dividing by 62.4 (which is the mass, in pounds, of a cubicfoot of a substance whose density is unity, i.e., water at 4 °C).

13-2 CORE METHOD

13-2.1 Introduction

With this method, a cylindrical metal sampler is pressed or driven*into the soil to the desired depth and is carefully removed to preserve aknown volume of sample as it existed in situ. The sample is dried to105 °C and weighed. The core method is usually unsatisfactory if morethan an occasional stone is present in the soil.

13-2.2 Method

Core samplers vary in design from a thin-walled metal cylinder to acylindrical sleeve with removable sample cylinders that fit inside. Sam-plers are usually designed not only to remove a relatively undisturbedsample of soil from a profile, but also to hold the sample during transportand eventually during further measurements in the laboratory, such aspore-size distribution or hydraulic conductivity. For the latter measure-ment it is desirable to have core diameters not less than 75 mm andpreferably 100 mm to minimize the effect of disturbed soil interfacingthe cylinder wall. For the same feason it is desirable that the height ofthe cylinder not exceed the

t i t i f eu V1JC 1UJ1VJI.

inner :o accept aedge at the lowediameters of thethe lower end, trsurface of the ouable in slightly diServices, UMC I

Where densimined, one can oon a pickup truesoil and removetslit running mosia rounded krufeSegments typicaland placed in ccthe probe modeltensions for grea'are available froSt., Fort Col.insStreet, Chickash;60202.

Fig. 13-1. Typical dcfor bulk density.

8 R 3 Q 0 7 6 3

BLAKE it HARTGE BULK DENSITY 365

/ years. Excavationsoil engineers for

excavation methodil is often too loose>reclude the. use ofnee the 1950s, par-

•ed from them. Therived units such as.'qua! to each other,Is which vary fromnenunitsofkgm"3

weight • volume"1)ity" are sometimeslanguage literature.sity "f a substance

illy to bulkm weight and

(lume weight" isand commercial

:h one may convertpounds, of a cubic

- at 4 °Q.

s pressed or driven,oved to preserve asample is dried to.atisfactory if more

metal cylinder to alat fit inside. Sam-itiveiy undisturbed>le during transportlaboratory, such asthe ' T measure-

tha*.ioilt t

5 mm andinterfacing

t the height of

A widely used and very satisfactory sampler consists of two cylindersfitted one inside the other. The outer one extends above and below theinner to accept a hammer or press at the upper end and to form a cuttingedge at the lower. The inside cylinder is the sample holder. The insidediameters of the two cylinders when nested are essentially the same atthe lower end, the inner being fitted against a shoulder cut on the innersurface of the outside cylinder. Figure 13-1 shows such a sampler (avail-able in slightly different design from the Utah State University TechnicalServices, UMC 12, Logan, UT 84322).

Where densities at various depths in a soil profile are to be deter-mined, one can obtain samples with a hydraulically driven probe mountedon a pickup truck, tractor, or other vehicle. The probe is forced into thesoil and removed hydraulicaUy. The probe tube has a 2- to 3-cm wideslit running most of the length of the tube, through which one can inserta rounded knife or spatula to slice off segments of the soil as desired.Segments typically 10 cm in length are cut and removed from the tubeand placed in containers for transport to the laboratory. Depending onthe probe model, samples can be taken to about l-m depth, though ex-tensions for greater depths are available for many models. Probe samplersare available from Giddings Machine Co., P.O. Drawer 2024, 401 PineSt., Fort Collins, CO 80522; A. D. Bull Enterprizes, 1904 South 21stStreet, Chickasha, OK. 73018; or Soiltest Inc., 2205 Lee St., Evanston, IL60202.

Ftf. 13**» Typical double cylinder.for bulk dtoaty.

t itmpter, for obtaining soil sunpier'

.Hill

Numerous hand-driven samplers have been described in the litera-ture. Some of the more accessible ones are described by Luiz {19471,Jamison etal. (1950), and U.S. Department of Agriculture (1954, p. 159).Mclnryre (1974) describes types of core samples and their properties andgives additional references,

13-U.l PROCEDUREThe exact procedure for obtaining the samples depends on the kind

of sampler used. The following steps apply when the widely known dou-ble-cylinder sampler is used.

Drive or press the sampler into either a vertical or horizontal soilsurface far enough to fill the sampler, but not so far as to compress thesoil in the confined space of the sampler. Carefully remove the samplerand its contents so as to preserve the natural structure and packing ofthe soil as nearly as possible. A shovel, alongside and under the sampler,may be needed in some soils to remove the sample wuhout disturbance.Separate the two cylinders, retaining the undisturbed soil in the innercylinder. Trim the soil extending beyond each end of the sample holder(inner cylinder) flush with each end with a straight-edged knife or sharpspatula. The soil sample volume is thus established to be the same asthe volume of the sample holder. In some sampler designs, the cuttingedge of the sampler has an inside diameter slightly less than the sampleholder, so as to reduce friction as the soil enters the holder. In these cases,determine the diameter of the cutting head and use this to calculate thesample holder volume. Transfer the soil to a container, place it in anoven at 105 °C until constant weight is reached, and weigh it The bulkdensity is the oven-dry mass of the sample divided by the sample volume.

13-2.2.2 COMMENTSIt is not necessary that soil be kept undisturbed during transport to

the laboratory and drying. A single sample cylinder can be reused if eachsample is transferred to another container. It is often desired, however,to make other measurements such as pore-size distribution, conductivity,or water retention in addition to bulk density on the same samples. Theserequire that they be kept undisturbed, each sample being transported inthe sample cylinder in which it was taken. Thus one must provide forsufficient cylinders. Frequently other measurements to be made in thelaboratory require that samples be kept at field water-content In thatcase cylinders must be placed in containers that do not permit loss ofwater during transport Waxed paper or plastic containers with lids aresatisfactory for this purpose.

Core samples should be taken in soils of medium water content Inwet soils, friction along the sides of the sampler and vibrations due tohammering are likely to result in viscous flow of the soil and thus incompression of the sample. When this occurs the sample obtained isunrepresentative, being more dense than the body of the soil. Compres-

sion may occur;',is taken, one shothe sampler is ;h<One can only rousample is changir

In dry or hardthe sample, and athe sampler intoshattering. Closeestimate whethersoils, soil level irthe sample is to

Bulk densityof soil, drying arcavation. In the:the hole with sarrubber-balloon rrinto the excavaticavation is justequal to the volidone it is possibvolume. Mensurmine the volumi

13-

13-3.2.1 SPECI.

13-3.2.1.1.2205 Lee Street,1. A metal funn

on the stem,sand contain*

2. A standard sabe fairly umfconsequent e;and retained

3. A template ccsquare, with

4. Scales to wei

4 HARTGE BULK DENSITY 367

the litera-itz (1947),

IX P. 159).jerries and

n the kindnown dou-

- zontal soilI m press the

-1 ne samplerpad ' of« er,

bance.inner

holderfe or sharpie same as

?^the cuttingJt~ the sample:hese cases,ilculate thece it in an:. The bulk>le volume.

-ansport toisedifeachl. however,nductivity,pies. Theseisported injrovide forlade in thent. In thatmit loss ofith !: •'- are

tent Indue. to

thus inobtained is. Compres-

- t

sion may occur even in dry soils if they are very loose. Whenever a sampleis taken, one should carefully observe whether the soil elevation insidethe sampler is the same as the undisturbed surface outside the sampler.One can only roughly estimate in this manner whether the density of thesample is changing because of sampling.

In dry or hard soils hammering the sampler into the soil often shattersthe sample, and an actual loosening during sampling may occur. Pressingthe sampler into the soil usually avoids the vibration that causes thisshattering. Close examination of the soil sample usually allows one toestimate whether serious shattering occurs. And, as in the case of wetsoils, soil level inside and outside the sampler must remain the same ifthe sample is to be considered satisfactory, (see also Mclmyre, 1974.)

13-3 EXCAVATION METHOD

13-3.1 Introduction

Bulk density is determined in this method by excavating a quantityof soil drying and weighing it, and determining the volume of the ex-cavation. In the sand-funnel method, the volume is determined by fillingthe hole with sand, of which the volume per unit mass is known. In therubber-balloon method, the volume is determined by inserting a ballooninto the excavation and filling it with water or other fluid until the ex-cavation is just full The volume of the excavated soil sample is thenequal to the volume of the fluid dispensed. If the excavation is carefullydone it is possible simply to measure its dimensions and calculate thevolume. Mensuration apparatus is described that enables one to deter-mine the volume of an irregular excavation.

13-3.2 Method (ASTM, 1958, p. 422-441)

13-3.2.1 SPECIAL APPARATUS13-3.2.1.1. Sand-Funnel Apparatus (see Fig. 13-2) (Soiltest, Inc.,

2205 Lee Street, Evanston, IL 60202).1. A metal funnel 15 to 18 cm at its largest diameter, fitted with a valve F~"

on the stem. Attached to the stem when the funnel is inverted is asand container.

2. A standard sand that is clean, dry, and free-flowing. Particle size should:be fairly uniform to avoid possible separation in the dispenser withconsequent error in calibration. Sand particles passing a no. 20 sieveand retained on a no. 60 neve are recommended (0.841-0.25 mm).

3. A template consisting of a thin, flat, metal plate approximately 30 cmsquare, with a hole 10 to 12 cm in diameter in its center."

4. Scales to weigh to 5 g,f t R 3 0 0 7 6 6

361 BLAKI 4 HAHTGE

Fig. 13-2. Apparatus for sand-funnel technique of determining soil bulk density in place.

13-3.2.1.2. Rubber-Balloon Apparatus.1. A thin-walled rubber balloon (may be purchased from Barr Inc., 1531

First Street, Sandusky, OH 44870. and the Anderson Rubber Co.. 310-T N. Howard Street, P.O. Box 170 Akron, OH 44309).

2. A 1000-cm3 graduated cylinder and a water container.3. A template, described in section 13-3.2.1.1 (3).

Rubber-balloon density apparatus is available from several manu-facturers supplying soil testing equipment. (One-supplier is Soiltest, Inc.,2205 Lee Street, Evanston, IL 60202.) The apparatus made commerciallyhas the convenience of a volumetrically calibrated water container-dis-penser, with suction facilities for returning the water to the container forre-use (Fig. 13-3).

13-3.2.1 J Mensuration Apparatus.1. Tape measure marked in millimeters.2. Flat metal plate approximately 50 cm square, with 30 to 40 evenly

spaced holes forming a grid through which the tape measure can beinserted. Alternatively, 3 wooden beams 3 by 3 by 80 cm with 5-cmmarkings may be used.

3. Four wood stakes approximately 10 cm long, one end sharpened.4. Scales to weigh to approximately 10 g,

13-3.2,2. PROCEDURE13-3.2.2.1. Sand-Fannti Procedure. Level the soil surface and re-

move loose soil at the test site. Place the template on the soil. Excavatea soil sample through the center hole of the template, leaving a hole witha diameter of approximately 12 cm and a depth of approximately 12 cm,

BLLX

Fig. 13-3. Apparnique.

or other valuRecover all eloose soil thathe oven-dryweighing it.

Determinlevel of the tnecessary, buflowing sand,plate, as is dolem of levelirfree flow of <being subtrac

Determirweighing it t<sand by lettiiflow as in thefrom it, deterof sand dispc

13-3.2.2.the templatethe precedinithe balloonvolume of w;markings toplaced on a

s*

-fJa

vKE & HARTGE BULK DENSITY 369

iity m place.

Barr Inc., 1531J^ubbcrCo., 310-

several manu-is Soiltest, Inc.,e commerciallyr container-dis-ie container for

JO to 40 evenlymeasure can be3 cm with 5-cm

d sharpened.

face and re-!>il. Excavate

, hole withiximately 12 cm.

Fif. 13-3. Apparatus for determining soil bulk density in place bv the rubber-balloon tech-nique. •

or other value as desired. A large spoon is convenient for excavating.Recover all evacuated soil in a container, being careful to include anyloose soil that has fallen in from the sides of the excavation. Determinethe oven-dry soil mass including stones by drying the soil to 10S °C andweighing it

Determine the volume of the test hole by filling it with sand to thelevel of the bottom of the template. Level the sand with a spatula ifnecessary, but disturb it as little as possible to avoid packing the free-flowing sand. (Dispensing the sand through a runnel placed, on the tem-plate, as is done with commercially available equipment, avoids the prob-lem of leveling the sand. The excavation as well as the funnel is filled byfree flow of sand, the predetermined weight required to fill the funnelbeing subtracted as a tare;)

Determine the weight of sand required to fill the test excavation byweighing it to the nearest 5 g. Precalibrate the mass-to-volume ratio ofsand by letting sand fail from a similar height and at a similar rate offlow as in the test procedure. Using the calibration curve or values derivedfrom it, determine the volume of the excavation from the measured massof sand dispensed*

Rnbbcr-Ballooft Procedvt. Level the soil surface, placethe template on the surface, and excavate a soil sample as described inthe preceding section. Place the rubber bgtapn in the test hole and fillthe balloon with water to the bottom or^R template. Determine thevolume of water required to the nearest 2 cm1. (A I000-cm3 graduate hasmarkings to 10 cm1, but one can estimate to 2 cm1 if the graduate isplaced on a horizontal surface.)

f lR300768

370 BLAKE * HAATGE

Calculate bulk density from the oven-dry mass of the excavated sam-ple and the volume of the test excavation.

13-3.2.2.3. Mensuration Procedure. Prepare the soil surface as de-scribed in previous procedures. Drive wooden stakes into the soil at fourcorners of a square about 40 cm on a side, allowing them to project I to3 cm above the soil surface. Place the metal plate on the stakes. Measurethe distance from the upper surface of the plate to the soil surface througheach of the holes. Remove plates and excavate soil from an area about30 by 30 cm to a depth of 10 cm. Weigh the soil including stones. Removean aliquot of reasonable size for determination of water content anddiscard the remainder. Replace the plate on the stakes and measure thedistance from the top of the plate to the excavated surface through eachof the holes as before.

If wooden beams are used in place of a meul plate. ;lace two beamsparallel, each resting on two stakes. With the third beam, bridge acrossthe other two and fr^m this datum, measure distance to the soil surfaceon a 5-cm grid using care that the tape is perpendicular to the beam. Asabove, excavate the soil sample and again measure distance from thethird beam to excavated soil surface on a 5-cm grid. Weigh the soilincluding stones. Remove an aliquot for ws:;r-content measurement anddiscard the remainder of the excavated son.

Calculate bulk density, ph from the we:ght of the soil corrected tooven dryness and the volume of the excavated soil. The volume is de-termined by summing the volumes around each depth measurement asfollows:

whered — depth after excavation,

do ~ depth before excavation, andA "• area covered by each measurement of the ruler. If holes are on

5-cm centers in the plate or measurements are made at 5-cmcenters with the wooden beams, A - 25 cm1.

By subsequent excavation of deeper layers in the same holes, one candetermine bulk density deeper in the profile by measurements from thesame datum.

13-3.2.3 COMMENTSBulk density can be estimated accurately by excavation methods car-

ried out carefully. Holes should have smooth, rounded walls. Protrudingstones should be included in the sample, care being used to round andsmooth the area from which stones are taken. A heavy pair of scissorscan be used to cut roots at the wail surface so the surrounding soil isundisturbed.

The relatively large sample (a cylinder of 12-cm diameter and of 12-cm depth- has a volume of 1357 cm1) has the advantage that small errors

BLTJC DE.NSITY

T«bltjl3-l. C

Soil material

Brown i*nd. trtct sBrown silt «nd clayBrown wad tad gti

som* tilt, trie* <±Brown till

Brown send, trie* 3Brown silt tad clayBrown sand and gn

scea silt, trace elBrown ial* A positive valu« L

in measuring w;advantage is theof 5 ..-m1 in liquia bulk density ofto perhaps 2 cmarises in determbottom of the teThe volume ofa considerably sneglected.

An error ofbulk density islikely to resultlevel at the botiresult in an err'required to assufor the dispensi

If one assunmethod and m>mulative error <volume measur

A comparisby Mintzer (19<

The bulk ctheir mass and

8 R 3 Q Q 7 6 9

"Tj£

(LAKE it HARTGE

i excavated sam-

nl surface as de-o the soil at four

—. n to project 1 to-- stakes. Measure

1 surface through•n an area about. stones. Removeiter content andand measure theice through each

.- place two beams! m, bridge acrossJ > the soil surface

to i* Seam. Asstan rom the

'eigh the soillUrement and

soil corrected toie volume is de-measurement as

If holes are on• made at 5-cm

e holes, one can•ments from the

on methods car-alls. Protrudingd to round andpair -f scissors

rour. j soil is

and of 12-small errors

BULK DENSITY

Table 13-1. Comparison of surface nuclear gauge and sand-con* method fordetermining Mil bulk density (Mintzer. 1961).

371

Soil mat* rial

Brown sand, trace siltBrown silt and clayBrown sand and gravel,

some silt, trace dayBrown till

Brown sand, tract siltBrown silt and clayBrown sand and gravel,

some silt trace dayBrown till

Number ofcomparisons

Wet bulk density, p*.94

64

Dry bulk density, <\94

64

Meaadifference

2.030.89

1.01-1.19

2.057.21

1.48-0.39

Extremedifference

-0.25-4.28-0.64-1.87

-2.27-7.75-3.97-1.60

-1.21-4.985.51-9.27

-1.71-8.32-4.53-3.21

t A poeitive value indicataa nuclear method gave higher bulk density value.

in measuring water volumes or sand weights are insignificant The dis-advantage is the lack of discrimination to a localized horizon. An errorof 5 cm3 in liquid volume will give an error of 0.005 in a sample havinga bulk density of 1.36 g cm"3. Though one determines the water dispensedto perhaps 2 cm3, a much greater source of error in water measurementarises in determining when the water in the excavation is level with thebottom of the template. Extreme care and judgment are required in this.The volume of the balloon itself, being of the order of 2 cm1, will givea considerably smaller error than the volume measurement, and can beneglected.

An error of 7 g in weighing the sand gives an error of 0.005 if thebulk density is 1.36 g cm ~J. As in the balloon technique, greater error islikely to result in the precision with which one can determine the sandlevel at the bottom of the template. An error of 1 mm in this level willresult in an error of 0.01 in the bulk density. Extreme care is thereforerequired to assure that the sand level is at the template bottom. The needfor the dispensing runnel in reducing this error is obvious.

If one assumes an excavation of 30 by 30 by 10 cm in the mensurationmethod and measures depth 36 times on a 5-cm grid, assuming a cu-mulative error of 1 mm in each of the depth measurements the error involume measurement is 1%.

A comparison of the sand-funnel and radiation methods was madeby Mintzer (1961), and the results are summarized in Table 13-1.

13-4 CLOD METHOD

13-4.1 Introduction

The bulk density of clods, or coarse peds, can be calculated fromtheir mass and volume. The volume may be determined by coating a

S R 3 0 0 7 7 0

37-2

clod of known weight with a water-repellent substance and by weighingtt first, in air, then again while immersed in a liquid of known density,making use of Archimedes' principle. The clod or ped must be sufficientlystable to cohere during coating, weighing and handling.

13-4.2 Method

13-4.2.1 SPECIAL APPARATUS1 . A balance, modified to accept the clod suspended below the balance

arm by means of a nylon thread or thin wire, to allow weighing theclod when it is suspended in a container of liquid.

2. A fine nylon thread or 28 to 30 gauge wire, to attach the clod to thebalance. A fine nylon hairnet makes a good container for the clod.

3. Saran solution. Dissolve 1 pan by weight of Saran resin (Dow SaranF-31O, Dow Chemical Co., Suite 500/ Tower No. 2, 1701 West GolfRoad, Rolling Meadows, IL 60008) in 7 parts by weight of methylethylketone in a 1 -gallon container in sufficient quantities to fill the con-tainer about three-quarters full. Manufacturer's instructions for safehandling of solvents should be carefully followed. Dissolution requiresabout an hour, with vigorous stirring. Since the solvent is flammableand explosive when its vapors are mixed with air, either hand-stirringor use of an air-driven stirrer should be employed in a well ventilatedhood. The solution can be stored for long periods if kept in a tightlyclosed container to prevent evaporation of the solvent

13-4.2.2 PROCEDURESecure the clod with two loops of the thread or wire, loops being at

right angles to one another, leaving sufficient thread or wire to connectto the balance arm. Weigh the clod and thread. Holding it by the thread,dip the clod into the saran solution. Suspend it in air under a hood for1 5 to 30 min to allow the solvent to evaporate. Repeat dipping and dryingone or more times as needed, to waterproof the clod. Weigh the clod,with its coating and the thread. Weigh it again when it is suspended inwater and note the water temperature. Determine the tare weight of thethread or wire. To obtain a correction for water content of the soil, breakopen the clod, remove an aliquot of soil, and weigh the aliquot beforeand after oven-drying it at 105 °C.

Calculate the oven-dry mass of the soil sample WM as follows, fromthe water content of the aliquot removed from the clod after other weightsare taken:

where,P, - di

W' MB rt *^t ^*

^u «• n<

^ - wPP - di

13-4.2.3 CC

The clo-other methc- ot take the

Extremtof sod. Clodfor these arsoil masses,

Ifbubblor if the w<clod, and th

Brashergested that1 part resingave the de

Precisicfor the diffethe error is

Using cgives a stansingle measby using laia greater nistandard de

Severalincluding p

where 9 - water content of the subsample in g/g andof clod or ped in air at its original water content.

Calculate bulk density as follows:

- net weightThetra

soil variesbration, nrradiation c

SLAKE & HARTCE

and by weighingf known density,jst be sufficiently

BULK DENSITY 373l!

elow the balancelow weighing the

h the clod to theer for the clod,•esin (Dow Saran,1701 West Golf.htofmethylethyles to fill the con-tractions for safessoluf'on requires/ent ammabie

hand-stirring'ell ventilated

:ept in a tightly

/em

ent.

~ ire. loops being ator wire to connectng it by the thread,- under a hood fordipping and dryingi. Weigh the clod,it is suspended intare weight of thet of the soil, breakthe aliquot before

dl as follows, fromafter other weights

W.„ — net weight

where/>„ - density of water at temperature of determination,

^o<u ~ oven-dry weight of soil sample (clod or ped),W^ - net weight of clod or ped in air,

Pflpw - net weight of soil sample plus saran in water,W^ - weight of saran coating in air, and

PP — density of saran.

13-4.2J COMMENTSThe clod method usually gives higher bulk-density values than do

other methods (Tisdall, 1951). One reason is that the clod method doesnot take the interclod spaces into account

Extreme care should be exercised to get naturally occurring massesof soil. Gods on or near the soil surface are likely to be unrepresentative,for these are often formed by packing with ullage implements. Naturalsoil masses, or coarse peds, that are more representative should be sought

If bubbles appear on the saran when the sample is weighed in wateror if the weight in water increases with time, water is penetrating theclod, and the sample must be discarded.

Brasher et al. (1966) first proposed use of saran coating. They sug-gested that for clods with large pores, a more viscous saran solution of1 pan resin to as little as 4 parts methylethyl ketone could be used. Theygave the density of saran to be 1.3 g cm'3.

Precision in calculating the bulk density would require a correctionfor the difference of the weight of the wire in air and in water. However,the error is negligible with thread or a 28-gauge wire.

Using clods as small as 40 g oven-dry weight and weighing to 10 mggives a standard deviation in the bulk density with 23 replications of asingle measurement of 0.07 g cm'3 (Hartge, 1963). This can be reducedby using larger clods or by weighing to 1 mg or both. Obviously, usinga greater number of samples for a determination would also reduce thestandard deviation.

Several other substances have been used to seal the clod against water,including paraffin, rubber, wax mixtures, and oils.

13-5 RADIATION METHODS

13-5.1 IntndKtiM

The transmission of gamma radiation through soil or scattering withinsoil varies with soil properties, including bulk density. By suitable cali-bration, measurements of either transmission or scattering of gammaradiation can be used to estimate bulk density.

I

• '

Ii5

i i

•I-'

374 BLAKE 4HAHTGE

In the transmission technique,,two probes at a fixed spacing are low-ered into previously prepared openings in the soil. One probe containsa Geiger tube, which detects the radiation transmitted through the soilfrom the gamma source located in the second probe. The scattering tech-nique employs a single probe containing both gamma source and detectorseparated by shielding in the probe. It can be used either at the soil surfaceor placed in a hole, depending on design of the equipment

Radiation methods have several advantages, among which are min-imum disturbance of the soil, short time required for sampling, acces-sibility to subsoil measurement with minimum excavation, and the pos-sibility of continuous or repeated measurements at the same point.

Both transmission and scattering techniques measure the bulk densityof all components combined. The densities of gaseous components areinsignificant in comparison to those of the solid or liquid components,and can therefore be ignored. It is necessary, however, to determine thewater content of the soil at sampling time and to apply a correction toobtain bulk density on a dry soil basis.

13-5.2 Methods

13-5.2.1 SPECIAL APPARATUS

Transmission apparatus is supplied by Troxler Electronics Labora-tories, P.O. Box 12057, Comwallis Road, Research Triangle Park, NC27709, following a design by Vomocil (1954). A design, including a dis-cussion of the theory of the method, calibration, and methods of makingmeasurements was included in the first edition of Methods of Soil Anal-ysis, Part 1 (Blake, 1965).

Scattering apparatus is supplied by Troxler Electronic Laboratories,P.O. Box 12057, Cornwallis Road, Research Triangle Park, NC 27709and by Soiltest Inc., 2205 Lee Street, Evanston, IL 60202.

13-5.2.2 PROCEDUREIt is recommended that the instructions supplied with the commercial

apparatus be followed. One may also wish to refer to the first edition ofMethods of Soil Analysis, Pan 1 (Blake, 1965).

13-5.2J COMMENTSThere is some radiation hazard with these methods. Gamma photons

are high-energy radiation. Some will pass through several centimeters oflead shielding. Comrr.* iy available equipment, as well as designs de-scribed in the literature, reduce the hazard to safe levels. But it is im-.portant to adhere strictly to time limits, distances, and other conditionsdescribed by the manufacturers. One should be equipped for and knowl-edgeable in means of checking the equipment for radiation levels ac-

BLTJtD

cordingequipm

Sin<on prottwo-prcexactly

Mirand thecomparsurfacewas use

Am. Soc,Mat.

Blake. GI. A

Brasher,to ccSci.

Z.FHirtK.1

Jamwon.SoU

LuttJ.Mclntyr

demsoiJsFur

Mintzer.detemea54.

TisdalLJ. A

U. S. I>sod!

Vomocu

.AK£ & HARTGE

pacing are low-probe containshrough the soilscattering tech-•ce and detector

_ the soil surface_ -nt.

which are min-ampling, acces->n, and the pos-ame point.the bulk density:omponents areid components,

- 3 determine thei a correction to

J

BULK DENSITY 375

ironies Labora-angle Park, NC

^including a dis--Miods of making

ds of Soil And-

c Laboratories,ark, NC 27709

i the commercial- first edition of

amma photonscentimeters of

1 as designs de-. But it is im-

ihei ditionsfor ana knowl-

levels ac-^^n 1

cording to the way it is handled in actual sampling. If there is doubt, theequipment should be checked for safety by a competent testing laboratory.

Since radiation transmitted from a source to a detector is dependenton probe spacing or sample thickness, care must be exercised with thetwo-probe sampler to assure that access holes are parallel and spacedexactly as in the calibration.

Mintzer (1961) reported comparisons of the surface-density probeand the sand-cone method on four engineering projects. He reported hiscomparisons on both the wet and dry bulk-density bases. He used asurface neutron meter for water content where the surface-density probewas used. His results are summarized in Table 13-1.

13-6 REFERENCES

Am. Sac Test Mater. 1958. Procedures for testing soils. American Society for Testing andMaterials, Philadelphia.

Blake, G. R. 1965. Bulk density. In C A. Black et ai. (ed). Methods of Mil analysis. Pan1. Agronomy 9:383-390.

Brasher. B. R., O. P. Franzmeier. V. Valassis. and S. E pavidson. 1966. Use of Saran Resinto coat natural soil clods for bulk density and moisture retention measurements. SoilSri. 101:108.

Harttt, K. H. 1965. Vergleich der Schrumpfung ungestorter Boden und gekneteter Fasten.Z. Friedr. Wilh. Univ. Jena, (math-nat. Reihe) 14:53-57.

Hartge, K. H. 1968. Heterogenitit des Bodens oder Queilung? Trans. Int. Congr. Soil ScL.9th 3:591-597. ^

Jamison. V. C. H. H. Weaver, and L F. Reed, 1959. A hammer-driven soil core sampler.Soil So. 69:487-496.

Lutz, J. F. 1947. Apparatus for collecting undisturbed soil samples. Soil Sd. 64:399-401.Mclntyre, D. S. 1974. Soil sampiinc techniques for physical measurements, chapter 3: Bulk

density, chapter 5; sad Appendix 1. In}. Loveday (ed.) Methods of analysis of irritatedsoils. Technical Communication no. 54, Comw. Bur. Soils, Comw. Atnc. Bureaux.Farnham Royal, Bucks,

Mintzer, S. 1961. Comparison of nuclear and sand-cone methods of density and moisturedeterminations for four New York State soils. In Symposium on nuclear methods formeasuring soil density and moisture. Am. Soc Testing Mater., Spec Tech. Pub. 293:45-J »

TisdaliA.L 1951. Comparison of methods of determining apparent density of soils. AustJ. Agric Raa, 1349-354.

U. S. Department of Agriculture. 1954. Diagnosis and improvement of saline and alkalisoils. USDAHandb. 60.

Vooocil, J. A. 1954. In situ measurement of soil bulk density. Agric Eng. 35:651-654.

I

Designation: 02216-80 vi A/twor Mwerw St*n*«

Standard Method forLaboratory Determination of Water (Moisture) Content of Soil,Rock, and Soil-Aggregate Mixtures1

This naadard is issued under the fixed demnaooo 0 22IS: the number immediately followtnc tbe deuinanoo indicates th* yew ofonpml adoption or. in the case of revision, (he yew of tut revtaon. A aumber in pwembeta indicates tbe yew of lax reapprov*!. Auipencntx epoloa d) indicates in ediionai change tiaee the last revision or reapejrovtl.

1. Scop*1.1 This method covers the laboratory determination of

the water (moisture) content of soil, rock, and soil-aggregatemixtures by weight For simplicity, the word "material"hereinafter refers to either soil, rock, or soil-aggregate mix-tures, whichever is most applicable.

1.2 The water content of a material is defined as the ratio,expressed as a percentage, of the mass of "pore" or "free"water in a given mass of material to the mass of the solidmaterial particles.

1.3 This method does not give true representative resultsfor. materials containing significant amounts of halloysite,montmorillonite, or gypsum minerals; highly organic soils;or, materials in which the pore water contains dissolved solids(such as salt in the case of marine deposits). For a materialof the previously mentioned types, a modified method of• *ing or data calculation may be established to give results

osistent with the purpose of the test

2. Summary of Method2.1 The practical application in determining the water

content of a material is to determine the mass of waterremoved by drying the moist material (test specimen) to aconstant mass in a drying oven controlled at 110 ± S*C andto use this value as the mass of water in the test specimen.The mass of material remaining after oven-drying is used asthe mass of the solid particles.

3. Sigaifkaac* ta4 Us*3.1 For many soil types, the water content is one of the

most significant index properties used in establishing a cor*relation between soil behavior and an index property.

3.2 The water content of a sod is used in almost everyequation expressittg thtrphaat relationships of air, water, andsolids in a given volume of material.

3.3 In fine-grained (cohesive) soils, the consistency of agiven soil type depends on its water content The watercontent of a soil, along with its liquid and plastic limit, isused to express its relative consistency or liquidity index.

• IT* actkrf • luder tfat junsdictto* of ASTM ConBiOM D-lt am Sat M*Rack tad • tie draa r««pooattSty at SuejcoamhMt Dll.OJ c* TOOMM. Ptabeinr

01 SOUaVMsy 30, 19KL Pubittrt July I MO. Or*M«y pot

O ait-71.• DZZU-OT.

3.4 The term "water" as used in geotechnical engineeringis typically assumed to be "pore" or "free" water and notthat which is hydrated to the mineral surfaces. Therefore, thewater content of materials containing significant amounts ofhydrated water at in-situ temperatures or less than 110'C cube mi^^ftflJTitj

3.5 The term "solid particles" as used in geotechnicalengineering, is typically assumed to mean naturally occurtucmineral particles that are not readily soluble in water. Thei*fore, the water content of materials containing extraneoamatter (such as cement, etc), water-soluble matter (such asalt) and highly organic matter typically require special treat-ment or a qualified definition of water content

4. ApperatM4.1 Drying Oven, thermostatically-controlled, preferably of

the forced-draft type, and maintaining a uniform temperatuAof 110 * S*C throughout the drying chamber.

4.2 Balances, having a precision (repeatability) of ±0.011for specimens having a mass of 200 g or less, ±0.1 g Tospecimens having a mass of between 200 and 1000 g, or 11g for specimens having a mass greater than 1000 g.

4.3 Specimen Containers—Suitable containers made <4material resistant to corrosion and a change in mass up*repeated heating, cooling, and cleaning. Containers witclose-fitting lids shall be used for testing specimens havinf'mass of less than about 200 g; while for specimens ha vim1

mass greater than about 200 g, containers without lids a*be used (Note 1). One container is needed for each'content determination.

Nort t—Thipurpow of ck)«c4ittiatlidii» to prevent U» of mo^

motion firm tat atmMptat foilowiac drying and before (Sail w^ing, <,

4.4 Desiccator—A desiccator of suitable size (a conventsize is 200 to 230-mm diameter) containing a hydrous &gel This equipment is only recommended for use ***containers having dole-fitting lids are not used. See 7.4.1.1

5. SaaalMS.I Keep tbe samples that are stored prior to testinf

noncorrodibie airtight containers at a temperatureapproximately 3 and 30*C and in an area that preventscontact with sunlight

3.2 The water content determination should be dot*

ft(i5?aii

itiaii

262 f l R 3 0 0 7 7 5

and

-10'Ccti

technics

r.Then.traneo*(such*

rerabryoJ

3.1 I forg,or±|

ass upoiicrs witkhaving ihaving!lids miycb water

; orption 4inal weis>

oussffiaise wha: 7.4.1.

" testing •• Oeiwcflntsdina

practicable after sampling, especially if potentially_ le containers (such as steel thin-walled rubes, paintetc.) or sample bags are used.

Test Specimen(.1 For water contents being determined in conjunction__ another ASTM method, the method of specimen seiec-

jjoo specified in that method controls.6,2 The manner in which the test specimen is selected and

i- required mass is basically dependent on the purpose (ap-plication) of the test, type of material being tested, and the

of sample (specimen from another test, bag, tube, split-etc.). In all cases, however, a representative portion of

total sample shall be selected. If a layered soil or more__ one soil type is encountered, select an average portioniodividual portions or both, and note which portion(s) was

__ in the report of the results.6.2.1 For bulk samples, select the test specimen from the

material after it has been thoroughly mixed. The mass ofjgoist material selected shall be in accordance with the follow-ing table:CM Retaining More Than About 10 % of Recommended Minimum Ma* of

Sampfc Moist Specimen, g100 to 200XX) to XX)500 to 1000

1500 to 30003000 to 10 000

6.22 For small (jar) samples, select a representative por-tion in accordance with the following procedure:

6.2.2.1 For coherionless soils, thoroughly mix the material,then select a test specimen having a mass of moist materialm accordance with the table in 6.2.1. See Note 2.

6.2.22 For cohesive soils, remove about 3 mm of materialfrom the exposed periphery of the sample and slice it in half(to check if the material is layered) prior to selecting the testjpecimen. If the soil is layered see 6.2. The mass of moistmaterial selected should not be less than 25 g or should be inaccordance with the table in 6.2.1 if coarse-grained particlesare noted. (Note 2).

6.3 Using a test specimen smaller than the minimum massindicated previously requires discretion, though it may beadequate for the purpose of the test A specimen having amast less than the previously indicated value shall be notedm the report of the resata.

2.0 mm (No. 10) i4.75 mm (No. 4) neve19 mm31 mm76 ma

ritiaa with a small mattepaitklt, it is appropriate not to

02216Non 3—To assist in the oven-drying of large test specimens, they

should be placed in containers having a large surface area (such u pans)and the material broken up into smaller aggregations.

Non 4-Tbe time required to obtain constant mass will vary depend-ing on the type of material, size of specimen, oven type and capacity.and other fitcion. The influence of these factors generally can be estab-lished by good judgment sod experience with the materials being testedand tbe apparatus being used. In most cases, drying a test specimen overnight (about 16 h) is sufficient. In cases where there is doubt concerningthe adequacy of drying, drying should be continued until tbe mass aftertwo successive periods (greater than lh h) of drying indicate an insignifi-cant change (tas than about 0.1 %). Specimens of sand may often bedried to constant mass in a period of about 4 h. when a forced-draft ovenis used.

Non 3—Oven-drying at 110 ± 5*C does not always result in watercontent values related to the intended use or the basic definition especiallyfor r?««»r*h containing gypsum or other minerals having significantamounts of hydrated water or for soil containing a significant amount oforganic material. In many cases, and depending on tbe intended use forthese types of matitriali, it might be more applicable to maintain thedrying oven at 60 ± 5*C or use a vacuum desiccator at a vacuum ofapproximately 133 Pa (10 mm Hg) and at a temperature ranging between23 and 60*C for drying. If either of these drying methods are used, itshould be noted in the report of tbe results.

Non 6—Since some dry materials may absorb moisture from moistspecimens, dried specimens should be removed before placing moistspecimens in the oven. However, this requirement is not applicable ifthe previously dried specimens will remain in tbe drying oven for anadditional time period of about 16 h.

7.4 After the material has dried to constant mass removethe container from the oven and replace the lid. Allow thematerial and container to cool to room temperature or untilthe container can be handled comfortably with bare handsand the operation of the balance will not be affected byconvection currents. Determine the mass of the containerand oven-dried material using the same balance as used in7.2. Record this value.

7.4.1 If the container does not have a lid, weigh the con-tainer and material right after their temperatures are suchthat the operation of the balance will not be affected byconvection currents or after cooling in a desiccator.

Non 7—Cocting in a desiccator is recommended since it preventsabsorption of moisture from tbe atmosphere during cooling.

8. Calcmiadosi8.1 Calculate the water content of the material as follows:

- wt)\ x 100 - x 100Non 2—In many

ssg a relatively lafsjt —— „,—— - , . — ~rr- ~rinclude this particle m ta* tM sparimrn If this occurs, it should be w

•otod in tbe report of tterMta. W

T «> • . - - '. rTOCMW* W,7.1 Select representative test specimens in accordance with W,

Section 6. "<7.2 Place the moist specimen in a dean, dry container of

known mast (Note 3), set the Bd securely in position, and^Btrminc the mass of the container>iu^ moist material usinga appropriate balance (4.2). Record these values.

7.3 Remove the lid and place the container with moistmaterial in a drying oven maintained at 110 ± 5*C and dryto a constant mass (Notes 4,5, and 6).

wherewater content, X,mass of container and moist specimen, g,mass of container and oven-dried specimen, g,mass of container, g,mass of water, g, andmass of solid particles,!.

9.9.1 The report (data sheet) shall include the following:9.1.1 Identification of tbe sample (material) being tested,

by boring number, sample number, test number, etc.9.1.2 Water content of the specimen to the nearest O.I %

or 1 %, Af^fiM^g on the purpose of the test

263 f l R 3 0 0 7 7 6

9.1.3 Indication of test specimen having a mass less thanthe minimum indicated in Section 6.

9.1.4 Indication of test specimen containing more than•• soil type (layered, etc).. 1.5 Indication of the method of drying if different from

oven-drying at 110 ± 5*C.

022199.1.6 Indication of any material (size and amount) ex-

cluded from the test specimen.10. Precision and Accuracy

10.1 Requirements for the precision and accuracy of thistest method have not yet been developed.

TT* A/n**ar Socfcfy far Tmeng *a Ux**» tarti no pantten molding ttm raMMy ct my p*w» rights MMTM fe canrweifenwtfi my nm umiKorno M m* mtratrl. uttn at trn» tttrutni art ocprMKy «vi»«g am OMmwnF*t** ngtn, **3 tf» run at inMngtmun at tuefi ngfa, m tranty tfwr own r

in of mt v«M«y <* any weft

il net rvtttta. wtfwinfl 1/uuM 0» idaN«»itf fa ASTM HttDqutfttn. Your common wH nct*v e**U oen«Mn0an « • /rwMng at tht ntonmNi

ITM^W yourtrwnam. wftcft you m«y «r«r«. ltyautmt ttm your comrtuna «€V» nor f*c«»»d *I9T0 A«« St.. PMiMW|pA«. 19103.

264 3 R 3 0 Q 7 7 7

1

Attachment 6

— 1. Sieves must be calibrated/checked according to Attachment 3from "Procedures in Sedimentary Petrology", as detailed onpages 65-67. Sieves must be calibrated with standard samplesor measurement of openings and must meet specifications ofTable 1. Narrative must describe procedure and data packagemust contain sieve accuracy testing results.

2. Samples must be prepared for analysis by ASTM D-421(Attachment 2).

_ 3. Grain size analysis by ASTM D-422 (Attachment 1) . Analysismust follow ASTM D-422 and must employ both sieve andhydrometer analysis as specified.

4. Percent moisture must be determined as per Section 8 of themethod.

5. Report requirements and data specifications are detailed inSection 18 of the method.i .

6. Laboratory must comply with purge file requirements.Contact SMO for details.

/IR300778

Attachment 7

Data package must include: all raw data, all instrument and/orequipment calibration results, calculations, blank results,duplicate results, chain-of-custody forms, SAS request forms, SASpacking list(s), or traffic report(s), copy of airbill(s)confirming sample receipt, and copies of analyst's logbooks (signedby analyst) with date and time of sample preparation and analysis.

The cover page and all sample reports forms MUST be labeled withthe complete EPA sample number as it appears on chain-of-custodyand CLP paperwork.

The case narrative must document all problems encountered and thesubsequent resolutions. List instrumentation and methods employedfor analysis.

For grain size distribution, the deliverables required in ASTMD422-63, Section 18 must be included. Also, include NBS Class "s"weight specifications for accuracy. Include balance check resultsof the actual balance reading for each weight used. Plots ofparticle size raw data must be included in the data package.

Graphical report of Grain Size must be done as per Section 18.12 ofmethod.

Results of balance check must be reported.

flR300779

U.S. ENVIRONMENTAL PROTECTION AGENCY SAS NUMBERCLP SAMPLE MANAGEMENT OFFICEP.O. BOX 818 - ALEXANDRIA, VIRGINIA 22313PHONE: 703/557-2490 - FTS/557-2490

SPECIAL ANALYTICAL SERVICESClient Request

Regional Transmittal Telephone Request

A. EPA Region/Client;EPA-REGION III-ARCS III

B. RSCC Representative; COLLEEN WALLING

C. Telephone Number; (301) 266-9180

D. Date of Request:___________

E. Site Name; AIW FRANK, CHESTER COUNTY, PA

Please provide below description of your request for SpecialAnalytical Services under the Contract Laboratory Program. Inorder to most efficiently obtain laboratory capability for yourrequest, please address the following considerations, ifapplicable. Incomplete information may result in a delay in theprocessing of your request. Please continue response on additionalsheets, or attach supplementary information as needed.

l. General Descrition of analytical services requested:

Analysis of 10 sediment samples for TOC by the method listedin Item 7.

2. Definition and number of work units involved (specify whetherwhole samples or fractions; whether organics or inorganics;whether aqueous or soil and sediments; and whether low,medium, or high concentration):

10 low concentration sediment samples for the above analysis.

3. Purpose of analysis (specify whether Super fund (enforcement orremedial action), RCRA, NPDES, etc.):

RI/FS - ARCS III

** SAS Approved By (signature):Date:

Q R 3 0 0 7 8 Q

4. Estimated date(s) of collection:

To be determined.

5. Estimated date(s) and method of shipment:

To be determined.

samples will be shipped overnight by overnight air carrier.This schedule is tentative and is dependant on the projectremaining on schedule. Sampling may continue into the week of

•

6. Number of days analysis and data required after laboratoryreceipt of samples:

Samples must be analyzed within 28 days of VTSR for eachsample. Written results within 35 days of the receipt of thelast sample.

7. Analytical protocol required (attach copy if other thanprotocol currently used in this program):

TOG - Method 29.3.5.2 from "Methods of Soil Analysis",Agronomy No. 9.

The method is attached.

8. Special technical instructions (if outside protocolrequirements, specify compound names/ GAS numbers/detection limits/ etc.):

For TOG, perform duplicate analysis on one of every 10samples or fractions thereof. Standardize the instrumentaccording to manufacturer's instructions.

9. Analytical results required (if known/ specify format for datasheets/ QA/QC reports/ Chain-of-Custody documentation/ etc.).If not completed, format of results will be left to programdiscretion:

Raw data, calculations, data sheets, blank results, duplicateresults, signed and dated chain-of-custody documentation, SASpacking list, copy of the air bill confirming sample receipt,SAS packing list, and SAS request form. In addition, for theTOG narrative, include a description of process utilized anddescription of problems encountered. Also include analystlogbook pages, .and weights and volumes used.

10. other (use additional sheets or attach supplementaryinformation/ as needed):

Laboratory must comply with purge file requirements.Contact SMO for details.

11. Name of sampling/handling contact:

Jeff Orient - NUS Corporation(412)-788-1080.

SR30078I

**»

12. Data Requirements:Precision Desired

Parameter________Detection Limit_____(+/-% or Concentration)

TOG (soil) 10 mg/kg ± 30%

TOG (water) 1 ppm ±20%

13. QC Requirements:Limits

Audits Required Frequency of Audits (Percent or Concentration)Blanks (TOC) 1/10 Below detection limit

Duplicate (TOC) 1/10 ± 30% RPD

Soil TOC certified standard 1/10 95% CI - report true values

Balance check with NBS Class "S" weights - report reults.

14. Action Required if Limits are Exceeded:Re-analyze samples once more and report both sets of data.

15. Request Prepared By:

Gregory L. Zimmerman - NUS Corporation - (412) 788-1080.June 6, 1991.

16. Request Reviewed By (CRL use only):Date:

Please return this request to the Sample Management Office as soonas possible to expedite processing of your request for SpecialAnalytical Services. Should you have any questions or need anyassistance, please contact your local Regional representative atthe sample Management Office.

fl.R300782

iRBON AND ORGANIC MATTER 19-3 ORGANIC CARBON 565

ers of this reagent adds 6 meq15% CaCOj in a 2-g soil sam-

3« present to ensure completesing > 3 ml of the 2N reagenti equivalent, it is preferable toreagent.

COMBUSTION

special apparatus listed in sec-

°7o: Bubble SO, through dis->btained. Keep the bottle well

sample that passes through ad of known water content to areviously ignited and cooled.IjSOj solution. After several• leaving the boat overnight inpellets. Repeat the treatment0,.lie C by one of the dry com-l). Report the C present in the

Soil Extracts

29-2.3.3.1.

tl, depending on the organic Cand add 1 ml of the HjSO,-in boiling water, and direct a

of the liquid in the flask. Re-il or less. Add five or six glass•oceed with the determination

29-3.4.4 COMMENTS

Drying of extracts is best accomplished in 100-ml flasks of the Kjeldahltype. A 2-liter beaker conveniently holds four flasks.

29-3.5 Rapid Bichromate Oxidation Techniques

29-3.5.1 INTRODUCTION AND PRINCIPLES

Schollenberber (1927) first proposed that the organic matter in soil maybe oxidized by treatment with a hot mixture of K2Cr2O7 and H2SO4 accord-ing to Eq. [9].

2 Cr2O,J- + 3 C° + 16 H* = 4 Cr3* + 3 CO2 + 8 H2O. [9]

After the reaction, the excess Cr,O,2- is titrated with Fe<NH4)2(SC>4)2'6H2O,and the Cr2(V~ reduced during the reaction with soil is assumed to beequivalent to the organic C present in the sample. It must be emphasizedthat all methods based on analysis of Cr2O7

l" remaining or Cr3* formed as-sume that C in soil organic matter has an average valence of zero. Althoughmost dichromate oxidation procedures described since the original Schol-lenberger method have involved chromic acid solutions or mixtures of con-centrated H2SO4 and aqueous K2Cr2O, solutions (Table 29-3), the use ofother oxidants has been proposed. Degtijareff (1930) suggested that a mix-ture of H2O2 and chromic acid be used to oxidize organic matter. However,Walkley and Black (1934) conclusively established that the addition of H2O2to chromic acid procedures gave fictitiously high values for organic C be-cause H2O2 reduces Cr2C>72~ in acid solution. Tinsley (1950) and Kalembasaand Jenkinson (1973) proposed that the chromic acid mixture used to oxi-dize organic C compounds be 9 and 4.5 , respectively, with respect toHiPO.. There is no evidence, however, to suggest that oxidation mixtures

Table 29-3. Digestion reagents used in various rapid dichromate methods_______________for organic C determinations._______________

Digestion reagent concentrationMethod

Schollenberger(1927)Tyurin(1931)Walkley & Black (1934)Anne (1945)Tinsley (1950)Mebiusl 19601Kalembasa & Jenkinson (1973)Nelson & Sommers (1975)Modified Mebius (described here)

K,Cr,O,t

0.350.400.330.160.400.2670.200.400.20

H.SO,—— N ———

3618252215201821.621.6

H.PO,

_--—9_5_-

t Based on Cr,0,'~ + 14H* = 2CrJ' + 7H,O + 6e'half reaction.

f lR300783

566 CARBON AND ORGANIC MATTER

containing Hi PCX are more efficient in oxidizing organic matter comparedwith K2Cr2O7-H:SO4 mixtures. The oxidizing mixture used in most pro-posed methods is between 0.16 to 0.3SN in K2Cr2O, and 15 to 25N in H2SO4(Table 29-3). However, Tyurin (1931), Tinsley (1950), and Nelson andSommers (1975) used an aqueous H2SO4 mixture that was 0.4/V in KjCrjOi,whereas Schollenberger (1927) used concentrated H2SC>4 (-36A/) as the sol-vent for KjCr2O7.

Schollenberger (1927) suggested that the soil-H2SO4-K2Cr2O7 mixturebe heated in a Pyrex test tube over a flame until the solution temperaturereached 175°C, at which time heating was discontinued. Later investigatorsrealized that the time and temperature of heating was critical and must bestandardized. Degtjareff (1930), Tyurin (1931), Schollenberger (1945), andJackson (1958) suggested that the soil-chromic acid mixtures should beheated in test tubes submerged in H2SO4 or oil baths for 10 min at 165°C, 5min at about 170°C, 5 min at 140°C, and 5 min at 155°C, respectively. Onthe other hand, Walkley and Black (1934) recommended that heat of dilu-tion of H2SO4 was satisfactory for oxidizing organic matter and that no ex-ternal heat was needed. More recently, other investigators have found thatan extended period of heating is required to obtain quantitative oxidationof organic C compounds by chromic acid (Anne, 1945; Tinsley, 1950;Mebius, 1960; Kalembasa & Jenkinson, 1973). Tinsley proposed that a coldfinger condenser fitted on an Erlenmeyer flask be used to prevent loss ofwater during the heating period, whereas the other workers usedErlenmeyer flasks fitted with Liebig condensers. Heating time varied from20 min to 2 hours, and the temperature of heating (boiling point of acidsolution) was dependent on the H2SO4 concentration in the oxidation mix-ture. Recently, Nelson and Sommers (1975) proposed that soil-chromic acidmixtures be heated under reflux in Folin-Wu nonprotein N tubes placed inan Al block on a hot plate. Heating time and temperature recommendedwere 30 min and 150°C, respectively.

Diphenylamine was the first oxidation-reduction indicator used for thetitration of excess Cr2(V with Fe2* (Schollenberger, 1927,1931, 1945; Alli-son, 1935). Later studies suggested that the diphenylamine endpoint couldbe improved by addition of HjPO4, NaF, or HF before titration (Schollen-berger, 1931, 1945; Walkley & Black, 1934), and these substances werewidely used in dichromate titrations. Peech et al. (1947) established thatbarium diphenylamine sulfonate in combination with HjPO4 was as effec-tive and more stable compared with diphenylamine and has been used as anindicator in other procedures (Tinsley, 1950). Jackspn (1958) recommendedthat o-phenanthroline be used as an indicator in Cr2O7

2" titrations becausethe color change (formation of the complex with Fe2*) occurs at higheroxidation-reduction potential compared with diphenylamine. A mixture ofo-phenanthroline and H,PO4 is normally used to give a good endpoint;however, the indicator has been successfully used without HjPO4 addition.A problem with o-phenanthroline is that the indicator tends to be absorbedby some suspended soil materials, obscuring the color change at the end-point. Therefore, the diluted chromic acid-soil mixture is often passedthrough a fast filter paper on a Buchncr funnel before titration. Simakov

29-3 ORGANIC CARBON

(1957) proposed that AAprCr2(V~ titrations with Fethranilic acid gives a verycurrently the indicator of c

Other methods of titrtors have been used to estirslight excess of Fe1* to tbtitrate the Fe2* with KMnCcedure, the only reagent thamounts of Fe2* and Cr2Cendpoint in the titration ofcurately by monitoring tcalomel electrodes attach1973). The endpoint of thewith0.02mloftitrant.

The amounts of Cr2<matter may also be estimaition or centrifugation (C.used to determine the amowith soil (Graham, 1948;Bolt, 1974; Gupta et al., 1quantitated at wavelengthlated to organic matter co1948; Sims & Haby, 197colorimeter to measure Crcentrifugation, thereby icuvette. In a comparison <that determine CrJ*, Metsthe preferred procedure.

Dichromate methodsnot give complete oxidatioactive forms of organic Cfound that on the averagecovered by the heat of dilltion factor of 1.32 be used

Table 29-4. Correction factomethod as detenru

Reference

Bremner & Jenkinson (1960s)Kalembasa & Jenkinson (1973Orphanos (1973)RichteretaL(1973)Nelson & Sommers (1975)

HR30078I4

ARBON AND ORGANIC MATTER

lizing organic matter compareding mixture used in most pro-.zCr,O, and 15 to 25Nin HjSO4nsley (1950), and Nelson andtture that was 0.4yVin K2CrjO7,•ated H2SO4 (- 36AO as the sol-

e soil-H2SO4-K2Cr2O7 mixtureuntil the solution temperature

iscontinued. Later investigatorssating was critical and must beII), Schollenberger (1945), andomic acid mixtures should be)il baths for 10 min at 165 °C, 5min at 155°C, respectively. Onecommended that heat of dilu-organic matter and that no ex-r investigators have found,that> obtain quantitative oxidation1 (Anne, 1945; Tinsley, 1950;t). Tinsley proposed that a coldask be used to prevent loss ofas the other workers usedsers. H<-a' '-e time varied fromheating foiling point of acidnitration in the oxidation mix-•roposed that soil-chromic acidi nonprotein N tubes placed innd temperature recommended

eduction indicator used for theiberger, 1927, 1931, 1945; Alli-diphenylaminc endpoint couldHF before titration (Schollen-l), and these substances were

et al. (1947) established thattion with H,PO4 was as effec-amine and has been used as anJackson (1958) recommended

r in Cr2O72~ titrations because

x with Fe2*) "-"urs at higherdiphenylarr,,.. .*. -nixture of

sed to give a good endpoint;used without H5PO« addition.ndicator tends to be absorbedthe color change at the end-

-soil mixture is often passednel before titration. Simakov

29-3 ORGANIC CARBON 567

(1957) proposed that N-phenylanthranilic acid be used as an indicator inCrjCV" titrations with Fe2*. Mebius (1960) confirmed that /V-phenylan-thranilic acid gives a very sharp and clean endpoint, and this compound iscurrently the indicator of choice for CrjO7

2~ titrations.Other methods of titration not involving oxidation-reduction indica-

tors have been used to estimate unreacted Cr2O72~. One approach is to add a

slight excess of Fe2* to the Cr2O72'-H2SO4-soil mixture and then back-

titrate the FeJ* with KMnO« (Smith & Weldon, 1941). In this titration pro-cedure, the only reagent that requires standardization is KMnO< if the sameamounts of Fe2* and Cr2O7

2~ are added to both samples and blanks. Theendpoint in the titration of Cr2O7

J" with Fe2* may also be estimated very ac-curately by monitoring the oxidation-reduction potential with Pt andcalomel electrodes attached to a potentiometer (Raveh & Avnimelech,1973). The endpoint of the titration involves a voltage change of -400 mVwith 0.02 ml of titrant.

The amounts of Cr:O72" remaining after reaction with soil organic

matter may also be estimated by colorimetry after removal of soil by filtra-tion or centrifugation (Carolan, 1948). Conversely, colorimetry may beused to determine the amounts of Cr1* formed from the reaction of Cr2Or2"with soil (Graham, 1948; Sinha & Prasad, 1970; Sims & Haby, 1971; DeBolt, 1974; Gupta et al., 1975; Baker, 1976). The green color due to Cr3* isquantitated at wavelength of 600 nm, and the absorbance is normally re-lated to organic matter concentration in soil by a standard curve (Graham,1948; Sims & Haby, 1971; De Bolt, 1974). Baker (1976) used a probecolorimeter to measure Cr3* absorbance directly in the reaction vessel aftercentrifugation, thereby avoiding a transfer into a spectrophotometercuvette. In a comparison of the methods that quantitate CrjO7

2" and thosethat determine Cr3*, Metson (1956) indicated that measurement of Cr3* isthe preferred procedure.

Dichromate methods that use heat of dilution or minimal heating donot give complete oxidation of organic compounds in soil although the mostactive forms of organic C are converted to COj. Walkley and Black (1934)found that on the average about 76% of the organic C in 20 soils was re-covered by the heat of dilution procedure, and they proposed that a correc-tion factor of 1.32 be used to account for unrecovered organic C. However,

Table 29-4. Correction factors for organic C not recovered by the Walkley and Blackmethod as determined for surface soils by various investigators.

Number of Qrgtadc C recovery Averagesoils ——————————— correction

Reference studied Range Average factor

Bremner & Jenkiason (1960a)Kalembasa & Jenkinson (1973)Orphanos (1973)RichteretaJL(1973)Nelson & Sommers (1975)

1522121210

/<57-9246-8069-7979-8744-88

8477758379

1.191.301.331.201.27

A R 3 0 0 7 8 5 ,

56! CARBON AND ORGANIC MATTER

the actual recoveries of organic C from the soils tested varied from 60 to86%. Allison (1960) reviewed available information on the recovery of or-ganic C in a wide variety of soils by the Walkley and Black procedure andshowed that the average recovery with different groups of soils varied from63 to 86% and that the correction factor varied from 1.16 to 1.59. Table29-4 gives data on the correction factor found to be required for theWalkley and Black procedure in investigations carried out during recentyears. Recoveries of organic C by the Walkley and Black technique werehighly variable, and the correction factor appropriate for individual soilsvaried from 1.09 to 2.27. The average correction factor appropriate for agroup of soils varied from 1.19 to 1.33. The above clearly indicate thatCriO7J"-HjSO4 methods that involve minimal heating give variable recoveryof organic C from soils. An average correction factor found for a group ofsoils may be applicable to the "average" soil in the group but will give er-roneous values for many soils in the group. Therefore, procedures such asthe Walkley and Black should be considered to give approximate or semi-quantitative estimates of organic C in soil because of the lack of an appro-priate correction factor for each soil analyzed. If an experimentally de-termined correction factor is not available for a particular group of soils,the use of 1.3 as the factor appears most reasonable over a range of soils.Methods that involve extensive heating, such as those of Tinsley (1950) orMebius (1960), do not require a correction factor because all of the organicC in the soil is oxidized to CO2. However, methods that involve minimalheating (e.g., Schoilenberger, 1927) require a small correction factor (e.g.,1.15) to account for unreacted organic C.

The rapid dichromate methods are subject to interferences by certainsoil constituents that lead to spurious results in some soils'(Walkley, 1947).Chloride, ferrous iron, and higher oxides of manganese have been shown toundergo oxidation-reduction reactions in chromic acid mixtures leading toincorrect values for organic C. The presence of significant amounts of Fe2*or Cl" in soil will lead to a positive error, whereas MnO2 will result in anegative error and low values for organic C.

Chloride interferes with dichromate methods through the formation ofchromyl chloride, as indicated in Eq. [4], which results in consumption ofCtiOi1'. Chloride interference may be eliminated by washing the soil free ofCl" before analysis or by precipitating the Cl' as AgCl by addition ofAg;SO4 to the digestion acid (Walkley, 1947; Quinn & Salomon, 1964). Al-ternatively, Walkley (1947) found that Eq. [10] may be used to correct or-ganic C values for soils having a Cl/C ratio of s 5:1:

Organic C in soil (%) = (Apparent % C in soil) - (% C1V12). [10]

When present in soil, Fe2* will be oxidized to FeJ* by Cr2O72', as indi-

cated in Eq. [11], resulting in a positive error in the analysis, i.e., givinghigh values for organic C content:

Cr20,2' + 6Fe2* + 14H* = 2Cr3* + 6Fe3* + 7H2O. [HI

29-3 ORGANIC CARBON

Appreciable Fe2* may be presresult when dichromate metht(Lee, 1939). However, Walkleyduced soils before analysis resudetermination of the organicwell-aerated soils are so small ithat no detectable interferencesamples may also lead to DOSTherefore, care should be takeor steel equipment before analy

The higher oxides of Mn (dizable substances when heated

2MnO2 + C9 +

Therefore, any reactive MnO2are analyzed by dichromate tecamounts of MnO2 and othereluded that in most soils the qusmall because only the freshlyreactions. Even in highly mangMnO2 present is able to comp«compounds. Therefore, interfe:ous error in the vast majority of

Other problems associatedtions about the average oxidaticweight of Q and recovery of hiAll dichromate methods assureoxidation state of zero and an ereacted with dichromate accordiiconducted to evaluate this assumethods using extensive heatintained with wet or dry combusgests that this assumption is re.involve little or no external hepresent in carbonized material:soot). For example, Walkley (18od recovered only 2 to 11 % of tdetailed study, Bremner and JeiBlack method gave low recovematerials, whereas methods invlenberger and Tinsley gave sub:organic C from such material:methods cannot be used to quarsoils or to discriminate betweenganic matter because organic Cthe chromic acid mixture. There

A R 3 Q 0 7 8 6

CARBON AND ORGANIC MATTER

he soils tested varied from 60 toi formation on the recovery of or-Valklcy and Black procedure andferent groups of soils varied fromvaried from 1.16 to 1.59. Tabler found to be required for the;ations carried out during recentalkley and Black technique were' appropriate for individual soilsrrection factor appropriate for aThe above clearly indicate that

nal heating give variable recoveryction factor found for a group ofsoil in the group but will give er-p. Therefore, procedures such asred to give approximate or semi-because of the lack of an appro-alyzed. If an experimentally de-t for a particular group of soils,reasonable over a range of soils.jch as those of Tinsley (1950) orfactor because all of the organic

r, methods that involve minimal•e a small correction factor (e.g.,

ibject to interferences by certainIts in some soils (Walkley, 1947).>f manganese have been shown to;hromic acid mixtures leading toce of significant amounts of Fe2*, whereas MnO2 will result in a

ethods through the formation ofwhich results in consumption ofinated by washing the soil free ofhe Cl" as AgCl by addition of7; Quinn & Salomon, 1964). Al-[10] may be used to correct or-

of<;5:l:

'o C in soil) - (<7o C1V12). [10]

lized to Fe3* by Cr2(V, as indi-rro» in the analysis, i.e., giving

29-3 ORGANIC CARBON 569

-f 6Fe3* + 7H2O. [HI

Appreciable Fe2* may be present in highly reduced soils, and errors mayresult when dichromatc methods are applied to such soils before drying(Lee, 1939). However, Walkley (1947) found that thorough air-drying of re-duced soils before analysis resulted in oxidation of Fe2* to Fe3* and accuratedetermination of the organic C present. The amounts of Fe2* present inwell-aerated soils are so small relative to the amounts of organic C presentthat no detectable interference is likely. Metallic iron (Fe°) present in soilsamples may also lead to positive interferences in dichromate methods.Therefore, care should be taken to ensure that soils are not ground with Fe'or steel equipment before analysis.

The higher oxides of Mn (largely MnO2) compete with Cr2O72~ for oxi-

dizable substances when heated in an acid medium according to Eq. [12].

2MnO2 + C° + 8H* = CO2 + Mn2* + 4H2O. [12]

Therefore, any reactive MnOj present will give a negative error when soilsare analyzed by dichromate techniques. Although soils contain substantialamounts of MnO2 and other higher oxides of Mn, Walkley (1947) con-cluded that in most soils the quantity of reactive (reducible) oxides of Mn issmall because only the freshly precipitated MnO2 will take part in redoxreactions. Even in highly manganiferous soils, only a small fraction of theMnO2 present is able to compete with Cr2O,2" for oxidation of organic Ccompounds. Therefore, interference from MnO2 is not thought to be a seri-ous error in the vast majority of soils.

Other problems associated with dichromate methods involve assump-tions about the average oxidation state of organic C in soils (i.e., equivalentweight of C) and recovery of highly reduced forms of organic C from soils.All dichromate methods assume that the organic C in soil has an averageoxidation state of zero and an equivalent weight of 3 g per equivalent whenreacted with dichromate according to Eq. [9] even though no studies have beenconducted to evaluate this assumption. However, the fact that dichromatemethods using extensive heating give organic C values similar to those ob-tained with wet or dry combustion where CO2 is determined directly sug-gests that this assumption is reasonably correct. Dichromate methods thatinvolve little or no external heating give very poor recovery of organic Cpresent in carbonized materials (e.g., charcoal, graphite, coal, coke, andsoot). For example, Walkley (1947) found that the Walkley and Black meth-od recovered only 2 to 11 % of the organic C present in such materials. In adetailed study, Bremner and Jenkinson (1960b) found that the Walkley andBlack method gave low recovery (<36%) of organic C from carbonizedmaterials, whereas methods involving external heat such as those of Schol-lenberger and Tinsley gave substantial (55-110%) and variable recovery oforganic C from such materials. The authors concluded that dichromatemethods cannot be used to quantitatively recover carbonized materials fromsoils or to discriminate between C in carbonized materials and C in soil or-ganic matter because organic C recovery varied with the time of heating ofthe chromic acid mixture. Therefore, unreliable results for organic C will be

flft300787

570 CARBON AND ORGANIC MATTER

obtained if dichromate methods are applied to soils containing significantamounts of carbonized materials. Dry combustion methods are most appro-priate for soils containing large amounts of elemental C.

29-3.5.2 WALKLEY-BLACK PROCEDURE (Walkley, 1946; Peech et al., 1947;Greweling & Peech, 1960)

29-3.5.2.1 Reagents.1. Potassium dichromate (KjCrzO,), 17V: Dissolve 49.04 g of reagent-grade

K2Cr2O7 (dried at 105°C) in water, and dilute the solution to a volume of1,000ml.

2. Sulfuric acid (H2SO4), concentrated (not less than %%): If Cl" is presentin soil, add Ag2SO, to the acid at the rate of 15 g/liter.

3. Phosphoric acid (HjPO4), concentrated.4. o-Phenanthroline-ferrous complex, 0.025A/: Dissolve 14.85 g of o-phen-

anthroline monohydrate and 6.95 g of ferrous suifate heptahydrate(FeSO4«7H2O) in water. Dilute the solution to a volume of 1 ,000 ml. Theo-phenanthroline-ferrous complex is available under the name of Fer-roin from the G. Frederick Smith Chemical Co. (Columbus, Ohio).

5. Barium diphenylamine sulfonate: Prepare a 0.16% aqueous solution.This reagent is an optional substitute for no. 4.

6. Ferrous suifate heptahydrate (FeSO4«7H2O) solution, 0.5N: Dissolve140 g of reagent-grade FeSO««7H2O in water, add 15 ml of cone sulfuricacid (HjSO.), cool the solution, and dilute it to a volume of 1,000 ml.Standardize this reagent daily by titrating it against It) ml of 17V potas-sium dichromate (K2Cr2O,), as described below.29-3.5.2.2 Procedure. Grind the soil to pass through a 0.5-mm sieve,

avoiding Fe or steel mortars. Transfer a weighed sample, containing 10 to25 mg of organic C, but not in excess of 10 g of soil, into a 500-ml wide-mouth Erlenmeyer flask. Add 10 ml of IN K2Cr2O,, and swirl the flaskgently to disperse the soil in the solution. Then rapidly add 20 ml of coneH2SO4, directing the stream into the suspension. Immediately swirl the flaskgently until soil and reagents are mixed, then more vigorously for a total of1 min. Allow the flask to stand on a sheet of asbestos for about 30 min.Then add 200 ml of water to the flask, and filter the suspension if experi-ence shows that the endpoint of the titration cannot otherwise be clearly dis-cerned. Add 3 to 4 drops of o-phenanthroline indicator, and titrate the solu-tion with 0.5JVFeSO4. As the endpoint is approached, the solution takes ona greenish cast and then changes to a dark green. At this point, add theferrous suifate heptahydrate drop by drop until the color changes sharplyfrom blue to red (maroon color in reflected light against a white back-ground). Make a blank determination in the same manner, but without soil,to standardize the Cr,O7

2". Repeat the determination with less soil if >75%of the dichromate is reduced.

Calculate the results according to the following formula, using a cor-rection factor/ = 1 .30 or a more suitable value found experimentally:

29-3 ORGANIC CARBON

Organic C, «7o =

29-3.5.2.3 Comments.titrant for excess CrjCV" in <The Smith and Weldon (1941)Cr2(V with Fe2*, and subseqsolution may also be used toreduction indicators that havtdiphenylamine sulfonate ancCr2CV reduced to Cr3* by nestimated colorimetrically.

29-3.5.3 MODIFIED MEBIUS

29-3.5.3.1 Special App.1.

2.

Erlenmeyer flasks (125 nground-glass joints (CornirWest condensers (30 cm) fglass joints at the lower enc

3. Electric hot plate extract!dividual rheostat controlsMulti-Unit Extraction Hea

29-3.5.3.2 Reagents.

1. Potassium dichromate soliK2Cr2O7 (oven-dry) in 200 i

2. Sulfuric acid (H2SO4), cone3. Ferrous ammonium sulf

6H2O], 0.2N: Dissolve 78cone H2SO4, and dilute to Iized daily because of slow c

4. Indicator solution: Dissol*0.107 g of sodium carbonat

29-3.5.3.3 Procedure. \containing not greater than 8flask.. Add exactly 10 ml of O.f(H2SO4 may be added by burtand place on a preheated elect:five soil samples to be heatecblanks are unheated mixturesH2SO4) for each day that anFe(NH4)2(SO4),.6H,O soluticblank. Gently boil each samplbetween the hot plate and botto cool for about 15 min, an

N AND ORGANIC MATTER

jils containing significantmethods are most appro-taJC.

ey, 1946; Pcechetal., 1947;

49.04 g of reagent-gradee solution to a volume of

in %%): If Cl- is present/liter.

ssolve 14.85 g of o-phen-us sulfate heptahydratevolume of 1,000 ml. Theunder the name of Fer-Columbus, Ohio).16% aqueous solution.

Jlution, 0.5/V: Dissolved 15 ml of cone sulfurica volume of 1,000 ml.

inst 10 ml of IN potas-

Jirough a 0.5-mm sieve,mple, containing 10 to»il, into a 500-ml wide-)7, and swirl the flaskidly add 20 ml of coneicdiately swirl the flaskigorously for a total oftos for about 30 min.e suspension if experi-therwise be clearly dis->r, and titrate the solu-, the solution takes on^t this point, add thecolor changes sharplyigainst a white back-mer, but without soil,vith less soil if >75<7o

formula, using a cor-experimentally:

29-3 ORGANIC CARBON

(meq K,Cr,O, - meq Fe 500(0.003X100)571

Organic C, % = g water-free soil x/. [13]

29-3.5.2.3 Comments. Ferrous ammonium sulfate is also a suitabletitrant for excess Cr2O,2' in conjunction with the Walkley-Black method.The Smith and Weldon (1941) modification involving complete reduction ofCr2O7

2' with Fe2*, and subsequent back-titration of excess Fe2* with MnOrsolution may also be used to estimate unreacted Cr2O7

2". Other oxidation-reduction indicators that have provided satisfactory results include bariumdiphenylamine sulfonate and JV-phenylanthranilic acid. The amounts ofCr2O7

2~ reduced to Cr3* by reaction with soil organic matter may also beestimated colorimetrically.

29-3.5.3 MODIFIED MEBIUS PROCEDURE

29-3.5.3.1 Special Apparatus.1. Erlenmeyer flasks (125 ml) fitted with female standard-taper 24/40

ground-glass joints (Corning 5000 or Kimble 26510).2. West condensers (30 cm) fitted with male standard-taper 24/40 ground-

glass joints at the lower end (Corning 2800 or Kimble 18190).3. Electric hot plate extraction unit (six plates per unit) fitted with in-

dividual rheostat controls (Labconco 60300, Precision 65500, Lab-LineMulti-Unit Extraction Heater, or equivalent).

29-3.5.3.2 Reagents.1. Potassium dichromate solution (K2Cr2O7), 0.5N: Dissolve 24.5125 g of

K2Cr2O7 (oven-dry) in 200 ml of deionized water, and dilute to 1 liter.2. Sulfuric acid (H2SO4), concentrated, not less than 96%.3. Ferrous ammonium sulfate hexahydrate solution [Fe(NH.,)2(SO4)2«

6H20], 0.27V: Dissolve 78.390 g of Fe(NH,):(SO4)2«6H2O in 50 ml ofcone H2SO4, and dilute to 1 liter with deionized water (must be standard-ized daily because of slow oxidation).

4. Indicator solution: Dissolve 0.100 g of /V-phenylanthranilic acid and0.107 g of sodium carbonate (Na2CO3) in 100 ml of water.

29-3.5.3.3 Procedure. Weigh an amount of < 100-mesh soil (< 0.5 g)containing not greater than 8 mg of organic C into a 125-ml Erlenmeyerflask. Add exactly 10 ml of O.SNKjCrjO, solution and 15 ml of cone HjSO,(HjSO, may be added by burette). Attach the flask to the West condenser,and place on a preheated electric hot plate. Include a blank in each group offive soil samples to be heated and at least two unboiled blanks (unboiledblanks are unheated mixtures of 10 ml of Q.SN K2Cr2O7 and 15 ml of coneH2SO4) for each day that analyses are performed. The normality of theFe(NH4)2(SO«)2»6H2O solution is determined by titrating the unboiledblank. Gently boil each sample for 30 min, and then insert an asbestos padbetween the hot plate and bottom of the Erlenmeyer flask. Allow the flaskto cool for about 15 min, and rinse the inside of the condenser with de-

f lR300789

U.S. ENVIRONMENTAL PROTECTION AGENCY SAS NUMBERCLP SAMPLE MANAGEMENT OFFICEP.O. BOX 818 - ALEXANDRIA, VIRGINIA 22313PHONE: 703/557-2490 - FTS/557-2490

SPECIAL ANALYTICAL SERVICESClient Request

Regional Transmittal Telephone Request

A. EPA Region/ClientlEPA-REGION III-ARCS III

B. RSCC Representative; COLLEEN WALLING

C. Telephone Number: (301) 266-9180

D. Date of Request:_____________

E. Site Name: AIW FRANK. CHESTER COUNTY. PA

Please provide below description of your request for SpecialAnalytical Services under the Contract Laboratory Program. Inorder to most efficiently obtain laboratory capability for yourrequest, please address the following considerations, ifapplicable. Incomplete information may result in a delay in theprocessing of your request. Please continue response on additionalsheets, or attach supplementary information as needed.

1. General Descrition of analytical services requested:

Analysis of 43 soil samples for pH, and Oxidation-ReductionPotential (Eh) by the methods listed in Item 7.

2. Definition and number of work units involved (specify whetherwhole samples or fractions; whether organics or inorganics;whether aqueous or soil and sediments; and whether low,medium, or high concentration):

43 low concentration soil samples for the above analysis.

3. Purpose of analysis (specify whether Superfund (enforcement orremedial action), RCRA, NPDES, etc.):

RI/FS - ARCS III

SAS Approved By (signature):Date:

f t R 3 0 0 7 9 0

4. Estimated date(s) of collection:

To be determined.

5. Estimated date(s) and method of shipment:

To be determined.

Samples will be shipped overnight by overnight air carrier. Thisschedule is tentative and is dependant on the project remaining onschedule. Sampling may continue into the week of

6. Number of days analysis and data required after laboratoryreceipt of samples:

pH and Eh must be analyzed within 48 hours of VTSR for eachsample. Written results are due within 35 days of the receiptof the last sample.

7. Analytical protocol required (attach copy if other thanprotocol currently used in this program):

pH - SW846-9045.

Eh - ASTM D-1498. A slurry will have to be created usingdeionized water if the moisture content of the sedimentis not high enough to allow the Eh to be measured. Stirfor at least half an hour. Refer to SW9045 Section 7.2.

All methods are attached.

8. Special technical instructions (if outside protocolrequirements/ specify compound names/ CAS numbers/ detectionlimits/ etc.):

See Attachment 1.

9. Analytical results required (if known/ specify format for datasheets/ QA/QC reports/ Chain-of-Custody documentation/ etc.).If not completed/ format of results will be left to programdiscretion:

See Attachment 2.

10. Other (use additional sheets or attach supplementaryinformation/ as needed):

Laboratory must comply with purge file requirements.Contact SMO for details.

11. Name of sampling/handling contact:

Jeff Orient - NUS Corporation(412)-788-1080.

12. Data Requirements:

Parameter ___ Detection LimitPrecision Desired

(+/-% or Concentration)

pH buffer check standard (1/10) should be within 0.05 pH units.

13. QC Requirements:Limits

Audits Required___Frequency of Audits (Percent or Concentration)

pH audit Material (EPA or 1/10commercially available)

95% CI (include truevalues with data)

Duplicate (Eh and pH) 1/10 + 10 mv/ + 0.3 pH units

.Eh 1/10 -(only if water has been added)

Blank should not registeran Eh.

pH meter calibration daily

E14. Action Required if Limits are Exceeded:

Re-analyze samples once more and report both sets of data andall associated QC.

15. Request Prepared By:

Gregory L. Zimmerman - NUS Corporation - (412.) 788-1080June 6, 1991; revised September 6, 1991.

16. Request Reviewed By (CRL use only):Date:

jr

Please return this request to the Sample Management Office as soonas possible to expedite processing of your request for SpecialAnalytical Services. Should you have any questions or need anyassistance, please contact your local Regional representative atthe Sample Management Office.

AR30Q792

ATTACHMENT 1

Calibrate pH meter using 4.0, 7.0 and 10.0 buffers. Indicateexpiration date for each buffer with lot number. Document dates ofanalysis and submit written worksheet of results.

flR300793

ATTACHMENT 2

Raw data, calculations, data sheets, blank results, duplicateresults, signed and dated chain-of-custody documentation, SASpacking list, copy of the air bill confirming sample receipt, andSAS request form. Narrative must include description of theprocess used to obtain the Eh readings and the weights and volumesused.

Provide all certified reference materials (audits) sheets frommanufacturer with true values and lot numbers.

J

METHOD 9045

SOIL pH

1.0 SCOPE AND APPLICATION

1.1 Method 9045 1s an electrometric procedure which has been approvedfor measuring pH 1n calcareous and noncalcareous soils.

2.0 SUMMARY OF METHOD

2.1 The soil sample 1s mixed either with Type II water or with a calciumchloride solution (see Section 5.0), depending on whether the soil 1sconsidered calcareous or noncalcareous. The pH of the solution 1s thenmeasured with a pH meter.

3.0 INTERFERENCES

3.1 Samples with very low or very high pH may give Incorrect readings onthe meter. For samples with a true pH of >10, the measured pH may beincorrectly low. This error can be minimized by using a low-sodium-errorelectrode. Strong add solutions, with a true pH of <1, may give incorrectlyhigh pH measurements.

3.2 Temperature fluctuations will cause measurement errors.

3.3 Errors will occur when the electrodes become coated. If anelectrode becomes coated with an oily material that will not rinse free, theelectrode can either (1) be cleaned with an ultrasonic bath, or (2) be washedwith detergent, rinsed several times with water, placed in 1:10 HC1 so thatthe lower third of the electrode 1s submerged, and then thoroughly rinsed withwater.

4.0 APPARATUS AND MATERIALS

4.1 pH Meter with means for temperature compensation.

4.2 Electrodes;4.2.1 Calomel electrode.4.2.2 Glass electrode.

4.2.3 A codaination electrode can be employed instead of calomel orglass.

4.5 Beaker: 50-mL.

9045 - 1RevisionDate September 1986

flR300795

4.6 Volumetric flask: 2-L1ter.

4.7 Volumetric flask: l-L1ter.

S.O REAGENTS

5.1 ASTM Type II waterimpurities.

(ASTM D1193): Water should be monitored for

5.2 Primary standard buffer salts are available from the National Bureauof Standards (NBS) and should be used 1n situations where extreme accuracy isnecessary. Preparation of reference solutions from these salts requires somespecial precautions and handling, such as low-conductivity dilution water,drying ovens, and carbon-dioxide-free purge gas. These solutions should bereplaced at least once each month.

5.3 Secondary standard buffers may be prepared from NBS salts orpurchased as solutions from commercial vendors. These commercially availablesolutions, which have been validated by comparison with NBS standards, arerecommended for routine use.

5.4 Stock calcium chloride solution (CaCl?). 3.6 M: Dissolve 1059 g ofCaCl2'2H20 1n Type II water in a 2-l1ter volumetric flask. Cool the solution,dilute 1t to volume with Type II water, and mix 1t well. Dilute 20 ml of thissolution to 1 liter with Type II water 1n a volumetric flask and standardize1t by titrating a 25-mL aliquot of the diluted solution with standard 0.1 N

using 1 ml of 5% I Crtty as the Indicator.

5.5 Calcium chloride (CaCl2), 0.01 M: Dilute 50 ml of stock 3.6 M CaCl2to 18 liters with Type II water. If the pH of this solution 1s not between 5and 6.5, adjust the pH by adding a little Ca(OH)2 or HC1. As a check on thepreparation of this solution, measure Its electrical conductivity. The speci-fic conductivity should be 2.32 + 0.08 mmho per cm at 25*C.

6.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING

6.1 All samples must be collected using a sampling plan that addressesthe considerations discussed 1n Chapter Nine of this manual.

6.2 Samples should be analyzed as soon as possible.

7.0 PROCEDURE

7.1 Calibration;

7.1.1 Because of the wide variety of pH meters and accessories,detailed operating procedures cannot be incorporated Into this method.Each analyst must be acquainted with the operation of each system andfamiliar with all Instrument functions. Special attention to care of theelectrodes 1s recommended.

9045 - 2Revision 0Date September 1986

3AR300796

7.1.2 Each instrument/electrode system must be calibrated at aminimum of two points that bracket the expected pH of the samples and areapproximately three pH units or more apart. Repeat adjustments onsuccessive portions of the two buffer solutions until readings are within0.05 pH units of the buffer solution value.7.2 Sample preparation and pH measurement of noncalcareous soils;

7.2.1 To 20 g of soil 1n a 50-mL beaker, add 20 ml of Type II waterand stir the suspension several times during the next 30 m1n.

7.2.2 Let the soil suspension stand for about 1 hr to allow most ofthe suspended clay to settle out from the suspension.

7.2.3 Adjust the electrodes 1n the clamps of the electrode holderso that, upon lowering the electrodes Into the beaker, the glasselectrode will be Immersed just deep enough Into the clear supernatantsolution to establish a good electrical contact through the ground-glassJoint or the fiber-capillary hole. Insert the electrodes Into the samplesolution 1n this manner. For combination electrodes, Immerse just belowthe suspension.

7.2.4 If the sample temperature differs by more than 2*C from thebuffer solution, the measured pH values must be corrected.

7.2.5 Report the results as "soil pH measured 1n water."

7.3 Sample preparation and pH measurement of calcareous soils;7.3.1 To 10 g of soil 1n a 50-mL beaker, add 20 mL of 0.01 M CaCl2

(Step 5.5) solution and stir the suspension several times during the next30 m1n.

7.3.2 Let the soil suspension stand for about 30 m1n to allow mostof the suspended clay to settle out from the suspension.

7.3.3 Adjust the electrodes 1n the clamps of the electrode holderso that, upon lowering the electrodes Into the beaker, the glasselectrode will be Immersed well Into the partly settled suspension andthe calomel electrode will be Immersed just deep enough Into the clearsupernatant solution to establish a good electrical contact through theground-glass joint or the fiber-capillary hole. Insert the electrodeInto the sample solution 1n this manner.

7.3.4 If the sample temperature differs by more than 2*C from thebuffer solution, the measured pH values must be corrected.

7.3.5 Report the results as "soil pH measured 1n 0.01 M

9045 - 3RevisionDate September 1986

flR300797

8.0 QUALITY CONTROL

8.1 Duplicate samples and check standards should be analyzed routinely.8.2 Electrodes must be thoroughly rinsed between samples.

9.0 METHOD PERFORMANCE

9.1 No data provided.

10.0 REFERENCES

10.1 None required.

9045 - 4RevisionDate September 1986

SR300798

METHOD

SOIL PH

7 1

if1

Calibrate•ach

i«trum«nt/ilrctroae

«y*tem

7.3. 1Add

C»CJi«olutlonto «otl: stir

7.3.2

7.Z. t

Add Tyo« IIwater to soil:

• tir

Let•oil suip*n*ion

stand for*30 ain

7. a. a

Let *oll•o»p«n«lon

•t*nd for 1 hr

9045 - 5Revision pDate September 1986

3R300799

METHOD sensSOIL OH

(Cent )nu«a)

Insert• lectroo,. Into••mple solution

7.3.4

Corr«ct«i«»»ured pH

values

••mole *nObuffer solutiontemos

by Z 'C7

Insert•Icctroaes into««mpl« solution

7.3.S

Report result*

Do ••mole «nobuffer solution

9045 - 6Revision 0Date September 1986

AR300800