STATISTICS ON THREE REGULATED ASBESTIFORM

AMPHIBOLES: LENGTH, WIDTH AND ASPECT RATIO

B. LI, PhDN.C. BATTA, MS, RPIH

S. C. SU, PhDN. K. BATTA, PE

BATTA LABORATORIES, INC.

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SIGNIFICANT PHYSICAL PROPERTY OF ALL

AMPHIBOLES:

CLEAVAGE

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AMPHIBOLE CRYSTAL FRAGMENTS BREAK PREFERABLY ALONG

CLEAVAGE PLANES BY:• Crushing• Milling• Grinding

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HOW BIG A ROLE CAN CLEAVAGE PLAY IN

DEFINING FIBER DIMENSIONS IN TERMS OF:• LENGTH•WIDTH• ASPECT RATIO

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AND MOST IMPORTANTLY:• SAMPLE PREPARATION• FIBER COUNT• WEIGHT ESTIMATE

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EXPERIMENTAL DESIGNMATERIAL• NIST STANDARD – ANTHOPHYLLITE

AND A MIXTURE OF TREMOLITE AND ACTINOLITE

• USING THE MIXTURE RATHER THAN EACH OF TREMOLITE AND ACTINOLITE WAS DETERMINED BASED ON THEIR CLOSE SIMILARITY IN PHYSICAL PROPERTY AND STATISTICAL BEHAVIOR OF FIBER DIMENSIONS AT THE BEGINNING OF THIS STUDY

METHOD• METHOD: INSTANT PLM PREP AND

MANUAL GRINDING WITH TIME INTERVALS OF: 0 (instant prep), 5, 15, 30, 60 AND 120 MINUTES

• TIME INTERVALS (i.e. 5, 15, … minutes) WERE INTENDED TO APPROXIMATE DIFFERENT SETTINGS OF MACHINE GRINDERS OR PULVERIZERS

MEASUREMENT• MEASUREMENT & RECORDING: PLM (0-

15) AND TEM (15-120) FOR LENGTH, WIDTH AND FIBER END SHAPES

• ALL FRAGMENTS (INCLUDING BUNDLES) WERE NON-SELECTIVELY, BUT SEPARATELY MEASURED REGARDLESS WHETHER THEY ARE IN THE FORMS OF CLUSTERS OR MATRICES (NOT SO COMMON IN THIS PREP DUE TO PURITY).

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RESULTS

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AVERAGE LENGTH CHANGE THROUGH

TIME

Fiber Length Change Through Time

0.00

50.00

100.00

150.00

200.00

250.00

0 5 10 15 30 60 120

Grinding Time (minute)

Leng

th in

Mic

ron

ANTHOPHYLLITE

TREMO-ACTINOLITE

0.00

0.50

1.00

1.50

2.00

2.50

3.00

15 30 60 120

AnthophylliteTremolite

PLM

TEM

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AVERAGE WIDTH CHANGE THROUGH

TIME

Fiber Width Change Through Time

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

0 5 10 15 30 60 120

Grinding Tim e (m inute)

Wid

th in

Mic

ron

ANTHOPHYLLITE

TREMO-ACTINOLITE

0.000.100.200.300.400.500.600.700.80

15 30 60 120

AnthophylliteTremolite

PLM

TEM

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ASPECT RATIO DISTRIBUTION OVER

TIME - ANTHOPHYLLITE

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14

15

16

17

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CHANGE IN AVERAGE ASPECT RATIO THROUGH

TIME

Change in Aspect Ratio Through Time

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0 5 10 15 30 60 120

Grinding Tim e (m inute)

Asp

ect R

atio

ANTHOPHYLLITE

TREMO-ACTINOLITE

0.000.501.001.502.002.503.003.504.004.505.00

15 30 60 120

AnthophylliteTremolite

PLM

TEM

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ASPECT RATIO DISTRIBUTION OVER

TIME FOR TREMOLITE AND ACTINOLITE IS

SIMILAR TO ANTHOPHYLLITE

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HOW DOES CHANGE IN FIBER LENGTH AND

ASPECT RATIO AFFECT WEIGHT AND COUNTS?

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FIRST:

HOW DO ASPECT RATIOS VARY WITH AMPHIBOLE

SPECIES?

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ANTHOPHYLLITEPLM

TEM

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TREMO-ACTINOLITEPLM

TEM

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SECOND:

HOW DO THESE CHANGES AFFECT ASBESTOS

COUNTS AND WEIGHT BY ANALYTICAL METHODS?

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IMPACT ON COUNTS FOR ANTHOPHYLLITE

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IMPACT ON COUNTS FOR TREMO-ACTINOLITE

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IMPACT ON WEIGHT/MASS FOR

ANTHOPHYLLITE

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IMPACT ON WEIGHT/MASS FOR TREMO-ACTINOLITE

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WHO MADE SUCH A “MASS”?

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CLEAVAGE?

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CLEAVAGE BEHAVIOR EXHIBITED BY FIBER

ENDS SHAPES

Variation in End Shapes Over Time: Tremo-Actinolite

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

0 5 10 15 30 120

Grinding Time

Per

cent

age

of O

ccur

renc

e

Rhombic Ends

Square Ends

PLM

TEM

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What Have We Learned So Far?

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CONCLUSION• CLEAVAGE IS AN INTRINSIC PROPERTY OF

ALL AMPHIBOLES• DIRECTLY OR INDIRECTLY IMPACTING ON

LENGTH, CLEAVAGE DICTATES ASPECT RATIO BEHAVIOR DURING SAMPLE PREP

• METHODS OF PREP CAN HAVE SIGNIFICANT IMPACT ON FIBER COUNTS AND WEIGHT

• METHOD ACCURACY IS A FUNCTION OF METHODS OF PREPARATION

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SUGGESTED CORRECTIVE ACTIONS• ACKNOWLEDGE THE EXISTENCE OF CLEAVAGE FIBERS. IN

ANOTHER WORD, CLEAVAGE FIBERS ARE ASBESTOS FIBERS AS LONG AS THEY MEET THE FIBER DEFINITION

• VARIOUS PREPARATION METHODS HAVE TO BE EVALUATED QUANTITATIVELY USING AN APPROACH SIMILAR TO THIS STUDY FOR THEIR IMPACT ON COUNTS AND WEIGHT ESTIMATE

• ANALYTICAL METHODS HAVE TO BE CHOSEN BASED ON PREP METHODS FOR OPTIMAL ACCURACY

• CLIENTS AND THE PUBLIC HAVE A RIGHT TO KNOW WHAT PREP METHODS WERE CHOSEN AND HOW THEY AFFECT THEIR RESULTS

• ALTHOUGH IT WAS KNOWN THAT GRINDING OR PULVERIZING WOULD HAVE IMPACT ON FIBER COUNTS OR WEIGHT ESTIMATE, UNCERTAINTY OR A CONVERSION FACTOR HAS TO BE QUANTITATIVELY DETERMINED AND REPORTED WITH THE RESULTS ACCORDING TO THE PREP METHOD ADOPTED

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THANK YOU ALL!

WHAT WE DO AT BATTA LABORATORIES

• ASBESTOS ANALYSIS (PLM, PCM & TEM)

• CHEMISTRY (ALL REGULATED METALS)

• RESEARCH AND DEVELOPMENT• INTERNSHIP PROGRAM• PUBLIC OUTREACH PROGRAM

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