representative subsampling at the laboratory...representative subsampling at the laboratory: new...

RepresentativeSubsampling at theLaboratory:New Guidance From USEPA

RepresentativeSubsampling at theLaboratory:New Guidance From USEPA

Jeffrey C. MyersAugust 18, 2004Jeffrey C. MyersAugust 18, 2004

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John Wiley & Sons 1997

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THE SEVEN “DEADLY” SAMPLING ERRORS

FUNDAMENTALERROR

FE

INCREMENTEXTRACTIONERROR EE

PREPARATIONERROR PE

INCREMENTDELIMITATION

ERROR DE

GROUPING &SEGREGATION

ERROR GE

LONG-RANGEFLUCTUATION

ERROR CE2

PERIODICFLUCTUATION

ERROR CE3

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John Wiley & Sons 1997

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COMPOSITIONAL CH

DISTRIBUTIONAL DH

FORMS OF HETEROGENEITYFORMS OF HETEROGENEITY

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ZERO DIMENSIONAL LOTZERO DIMENSIONAL LOTZERO DIMENSIONAL LOT

DEFINITIONOF CH

DEFINITIONOF CH

DEFINITIONOF DH

DEFINITIONOF DH

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THE TRIAD APPROACH FROM EPA

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Uncertainties add as vectors (aUncertainties add as vectors (a22 + b + b22 = c = c22))

AA

3 X3 X

Total Uncertainty AnalyticalUncertainty

Sampling Uncertainty

CC1/3 X1/3 X

AACCBB

BB

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Sampling = 95%

Analytical = 5%Analytical = 5%

39,800 On-site41,400 Lab

500 On-site416 Lab

164 On-site136 Lab

27,800 On-site42,800 Lab

24,400 On-site27,700 Lab

1,280 On-site1,220 Lab

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6 3

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331 On-site 286 Lab

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John Wiley & Sons 1997

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John Wiley & Sons 1997

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John Wiley & Sons 1997

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MASSDFE ))(5.22( 3

2 =

� FE = FUNDAMENTAL ERROR� D = DIAMETER OF LARGEST

PARTICLE� MASS = MASS OF ANALYZED PORTION

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SAMPLE MASS APPROX. ERROR 1 gm 40% 2 gm 30% 5 gm 20% 10 gm 15% 20 gm 10% PARTICLE SIZE = 2mm

SAMPLE MASS APPROX. ERROR 1 gm 40% 2 gm 30% 5 gm 20% 10 gm 15% 20 gm 10% PARTICLE SIZE = 2mm

RELATIVE FUNDAMENTAL ERROR: PARTICLESIZE REPRESENTATION

(RAMSEY 1990)

RELATIVE FUNDAMENTAL ERROR: PARTICLESIZE REPRESENTATION

(RAMSEY 1990)

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John Wiley &

Sons 1997

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� CONING & QUARTERING� ALTERNATE SHOVELING� FRACTIONAL SHOVELING� RIFFLE SPLITTERS

� CHUTE� ROTARY

� CONING & QUARTERING� ALTERNATE SHOVELING� FRACTIONAL SHOVELING� RIFFLE SPLITTERS

� CHUTE� ROTARY

SUBSAMPLING METHODSSUBSAMPLING METHODSSUBSAMPLING METHODS

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CONING&

QUARTERING

CONING&

QUARTERING

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RIFFLE SPLITTERSRIFFLE SPLITTERS

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CORRECT ANDINCORRECTSAMPLINGDEVICES

CORRECT ANDINCORRECTSAMPLINGDEVICES

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SCOOPSCOOP

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SPATULASPATULA

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JAPANESESLABCAKE

JAPANESESLABCAKE

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CORRECT DELIMITATION WITH JAPANESE SLAB CAKES

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SUMMARY

- PIERRE GY’S SAMPLING THEORY- EPA/600/R-03/027- http://cluin.org/publications/db/db_search.cgi?new=1&title=1&submit_search=1

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Jeff MyersWashington Safety Management Solutions

jeff.myers@wsms.comhttp://www.gemdqos.com