Trace Elements in Coal Dust by Spark-Source Mass Spectrometry

/^oal workers' pneumoconiosis (CWP) is a major health hazard among. ^ miners in the Appalachian coal regions, disabling many and com tributing to the ...
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4 Trace Elements in Coal Dust by Spark-

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-SourceMass Spectrometry A. G. SHARKEY, JR., T. KESSLER, and R. A. FRIEDEL Spectro-Physics, Pittsburgh Energy Research Center, 4800 Forbes Ave., Pittsburgh, Penn. 15213

Spark-source trace

mass spectrometry

elements

and prepared obtain

in 10 pairs coal dusts.

information

for

The

dusts.

Samples West

For a majority ing Ag,

Cd,

object of the research

is to

Cr, Rb,

the

the

incidence

composition

of of

eight coal seams in

Virginia,

of the sample Cu,

dusts

with

representing

Virginia,

determine mine

correlating

workers' pneumoconiosis vania,

has been used to

of respirable-range

and

Utah

were

Pennsylanalyzed.

pairs, several elements

Ca,

Cl, P, and

includ-

Br show

higher

values in the mine dust than the coal.

A limited

tion of the organic

with the mine

indicates

material

an additional

not derived

from the

associated

series of highly

saturated

coal mine

investigadusts

material

coal.

/ ^ o a l w o r k e r s ' p n e u m o c o n i o s i s ( C W P ) is a major h e a l t h h a z a r d a m o n g ^

m i n e r s i n the A p p a l a c h i a n c o a l regions, d i s a b l i n g m a n y a n d

t r i b u t i n g to the d e a t h of others.

com

It is n o w w i d e l y a c c e p t e d that C W P

results f r o m the i n h a l a t i o n of c o a l dust, b u t , since the i n c i d e n c e of the disease a m o n g m i n e r s appears to v a r y w i t h the r e g i o n or c o a l b e d b e i n g m i n e d , i d e n t i f i c a t i o n of the specific l u n g i r r i t a n t ( s ) responsible m a y h e l p to m i n i m i z e or e l i m i n a t e the h a z a r d .

However, information currently

a v a i l a b l e o n c o a l dust c o m p o s i t i o n is insufficient to a t t e m p t a n y c o r r e l a tion w i t h C W P incidence. L e e s u m m a r i z e d the p a n e l d i s c u s s i o n at a m e e t i n g of the E n v i r o n m e n t a l H e a l t h Sciences A d v i s o r y C o u n c i l w h i c h c o n c e n t r a t e d p r i m a r i l y o n the etiology of C W P ( I ). O n e area of r e s e a r c h r e c o m m e n d e d b y the p a n e l was w h a t c o m p o n e n t ( s ) is associated w i t h a specific r a n k of c o a l that results i n i n c r e a s e d i n c i d e n c e of C W P . W a r d e n , i n d i s c u s s i n g the m e d i c a l aspects of C W P , stated t h a t "the fate of the p a r t i c u l a t e s r e t a i n e d 48 Babu; Trace Elements in Fuel Advances in Chemistry; American Chemical Society: Washington, DC, 1975.

4.

SHARKEY E T AL.

Spark-Source

Mass

49

Spectrometry

i n the l u n g is r e l a t e d to the s o l u b i l i t y of the p a r t i c u l a t e , as w e l l as to its c h e m i c a l activities, surface r e a c t i v i t y , a n d i m m u n o l o g i c a l factors"

(2).

Saffiotti a n d c o - w o r k e r s d e m o n s t r a t e d i n a n i m a l tests that p o l y n u c l e a r a r o m a t i c c o m p o u n d s , s u c h as are p r e v a l e n t i n c o a l dust, w h e n c o m b i n e d w i t h i n o r g a n i c m a t e r i a l p r o d u c e some of t h e most severe l u n g irritations ( 3 ). L a n g e r a n d Selikoff s h o w e d that the c h e m i c a l c o m p o s i t i o n of asbestos fibers is a l t e r e d w h e n i n contact w i t h l u n g tissue b e c a u s e fluids assoDownloaded by UNIV OF CALIFORNIA SAN DIEGO on April 5, 2016 | http://pubs.acs.org Publication Date: September 1, 1975 | doi: 10.1021/ba-1975-0141.ch004

c i a t e d w i t h l u n g tissue are effective asbestos

(4).

in leaching magnesium from

the

T h e p r e v i o u s l y stated investigations i n d i c a t e that b o t h

o r g a n i c a n d i n o r g a n i c constituents of t h e c o a l dust c o u l d h a v e a b e a r i n g on the i n c i d e n c e of C W P . C o a l w o r k e r s ' p n e u m o c o n i o s i s c a n be defined s i m p l y as the a c c u m u l a t i o n of dust i n the l u n g a n d the r e a c t i o n of l u n g tissue to the presence of that dust. T h e t e r m , r e s p i r a b l e dust, has b e e n g i v e n to dust p a r t i c l e s lçss t h a n 5 /xm i n size, a l t h o u g h a f e w p a r t i c l e s u p to 10

have been

o b s e r v e d i n lungs. T h e r e s p i r a b l e dust g e n e r a l l y has a c o m p o s i t i o n q u i t e different f r o m dust i n the same size range, w h i c h is p r e p a r e d f r o m c o a l f r o m the same m i n e . C o n s i d e r a b l e c o n t a m i n a t i o n of a i r b o r n e dust c a n o c c u r f r o m other materials s u c h as r o c k dust ( c a l c i u m c a r b o n a t e ) , slate, a n d o r g a n i c c o n t a m i n a n t s . T h e m i n e dust a n d c o a l d u s t c a n also differ i n shape factor, d e n s i t y , a n d other properties. V e r y little d a t a h a v e b e e n r e p o r t e d o n the analysis of elements i n w h o l e c o a l a n d m i n e dusts i n p a r t i c u l a r . K e s s l e r , S h a r k e y , a n d F r i e d e l a n a l y z e d trace elements i n c o a l f r o m m i n e s i n 10 c o a l seams l o c a t e d i n Pennsylvania, West Virginia, Virginia, Colorado, and U t a h (5).

Sixty-

f o u r elements r a n g i n g i n c o n c e n t r a t i o n f r o m 0.01 to 41,000 p p m w t w e r e determined.

S e v e r a l surveys p u b l i s h e d p r e v i o u s l y h a v e p r o v i d e d

data

o n the c o n c e n t r a t i o n of m i n o r elements i n ashes f r o m coals r a t h e r t h a n a d i r e c t d e t e r m i n a t i o n o n the w h o l e coals or m i n e dusts. P r e v i o u s i n v e s t i gations i n c l u d e studies b y H e a d l e e a n d H u n t e r ( 6 ) , N u n n , L o v e l l , a n d W r i g h t ( 7 ) , Abernethy, Peterson, and G i b s o n ( 8 ) , II,

a n d others

(9,

10,

12). T h e p u r p o s e of this i n v e s t i g a t i o n is to d e t e r m i n e i f there are a n y

differences i n c o m p o s i t i o n b e t w e e n samples of r e s p i r a b l e dust c o l l e c t e d i n c o a l mines a n d c o a l dust of r e s p i r a b l e size a n d s i m i l a r p a r t i c l e size d i s t r i b u t i o n p r e p a r e d f r o m a representative c o a l s a m p l e f r o m the same mine.

T h i s r e p o r t hopes to p r o v i d e survey analyses i n d i c a t i n g the g e n -

e r a l c o n c e n t r a t i o n l e v e l of m a n y trace elements i n the r e s p i r a b l e - r a n g e m i n e dust, i n c l u d i n g h e a v y metals of h i g h c u r r e n t interest. M o r e precise d a t a c a n b e o b t a i n e d b y a t o m i c a b s o r p t i o n a n d n e u t r o n a c t i v a t i o n or other t e c h n i q u e s for c e r t a i n trace elements s h o w i n g h i g h or h a z a r d o u s concentrations i n the m i n e dusts a n a l y z e d b y spark-source mass spectrometry

(SSMS).

The

d e t e r m i n a t i o n of

possible

differences

Babu; Trace Elements in Fuel Advances in Chemistry; American Chemical Society: Washington, DC, 1975.

in

the

50

TRACE

ELEMENTS

IN

FUEL

o r g a n i c m a t e r i a l associated w i t h the same 10 s a m p l e p a i r s is also p a r t of this p r o g r a m . H i g h - r e s o l u t i o n mass spectra are i n c l u d e d to illustrate the data obtained. Experimental

Work

Sample Preparation. R e p r e s e n t a t i v e samples for the analysis of the

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elements i n the c o a l w e r e o b t a i n e d b y the f o l l o w i n g p r o c e d u r e . 400 lbs of r a w c o a l w e r e o b t a i n e d f r o m e a c h of the seams i n v e s ­ t i g a t e d . T h e r a w c o a l s a m p l e was first c r u s h e d to % X 0 i n . T h e c r u s h e d c o a l w a s d i v i d e d b y successive riffling to o b t a i n a final 25-lb s a m p l e w h i c h w a s t h e n a i r d r i e d a n d d i v i d e d t w i c e to o b t a i n a 6.25-lb s a m p l e . T h e 6.25-lb s a m p l e ( % X 0 i n . ) w a s r e d u c e d to —200 m e s h b y g r i n d i n g o n a m i c r o m i l l e q u i p p e d w i t h S t e l l i t e blades. U s i n g a w i n d t u n n e l — A n d e r s o n S a m p l e r system, the —200-mesh c o a l was s e p a r a t e d i n t o the f o l l o w i n g p a r t i c l e sizes: > 9.2, 5.5-9.2, 3.3-5.5, 2.0-3.3, 1.0-2.0, a n d < 1.0 μτη. P r e v i o u s w o r k has s h o w n that the 3.3-5.5 μτη c o a l f r a c t i o n has a p a r t i c l e size d i s t r i b u t i o n s i m i l a r to that of r e s p i r a b l e m i n e dust c o l l e c t e d o n p e r s o n a l samplers d u r i n g m i n i n g operations (13).

T h i s f r a c t i o n was

u s e d for t h e s p a r k - s o u r c e analyses. T h e coals u s e d i n this i n v e s t i g a t i o n are i d e n t i f i e d i n T a b l e I.

T h e r e s p i r a b l e dusts w e r e

obtained

from

p e r s o n a l s a m p l e r filters s u b m i t t e d to the D u s t G r o u p , P i t t s b u r g h T e c h ­ n i c a l S u p p o r t C e n t e r , F e d e r a l B u r e a u of M i n e s . T h e samples w e r e c o l ­ l e c t e d d u r i n g a c t u a l m i n i n g operations. Table I. Sample No. 1 2 3 4 5 6 7 8 9 10

Rank

Identification of Seams Location

Seam

a

mvb hvAb hvAb hvAb hvAb hvAb lvb lvb lvb lvb

Cambria Co., P a . Fayette Co., W . V a . Allegheny Co., P a . Greene C o . , P a . Allegheny Co., P a . Carbon Co., Utah McDowell Co., W . V a . Buchanan Co., V a . Buchanan Co., \ a. Wise Co., V a .

Lower Kittanning Powellton T h i c k Freeport Pittsburgh Pittsburgh Sunnyside Pocahontas N o . 4 Pocahontas N o . 3 Pocahontas N o . 3 Taggart

r

° m v b = m e d i u m v o l a t i l e b i t u m i n o u s , h v A b = h i g h volatile A b i t u m i n o u s , l v b = volatile bituminous.

Instrumentation.

low

T h e i n s t r u m e n t u s e d i n this i n v e s t i g a t i o n w a s a

c o m m e r c i a l M a t t a u c h - H e r z o g mass s p e c t r o m e t e r e q u i p p e d w i t h p h o t o ­ g r a p h i c a n d e l e c t r i c a l d e t e c t i o n systems a n d a n R F s p a r k source.

The

r e s o l u t i o n of the i n s t r u m e n t was 1 p a r t i n 5,000. A l l trace elements w e r e determined from

mass

spectra recorded

on

Ilford Q-2

photographic

Babu; Trace Elements in Fuel Advances in Chemistry; American Chemical Society: Washington, DC, 1975.

4.

SHARKEY E T AL.

plates.

Spark-Source

Mass

51

Spectrometry

M a j o r elements w e r e d e t e r m i n e d u s i n g t h e e l e c t r i c a l d e t e c t i o n

system. Electrode Preparation.

Electrodes were prepared b y mixing the

samples w i t h e q u a l parts o f p u r e g r a p h i t e . T o i n s u r e h o m o g e n o u s

mix­

i n g a n d to d e t e r m i n e t h e p l a t e sensitivity, 5 0 p p m i n d i u m w a s a d d e d as a n i n t e r n a l s t a n d a r d to t h e s a m p l e - g r a p h i t e m i x t u r e .

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p p m a r e g i v e n i n terms o f w e i g h t . )

( I n this p a p e r ,

T h e mixtures were pressed into

H NO Li

Be

Β

C

Ν

0

F

100

100

100

ND

ND

ND

100

No

Mg

Al

100

100

100

Κ

Co

Sc

Ti

V

Cr

Mn

Fe

100

100

100

100

100

100

100

100

Co 1 00

Ni 100

Si

Ρ

S

CI

100

100

100

100

Cu

Zn

Go

Ge

As

Se

Br

100

100

100

100

100

100

100

In Stond-

Sn

Sb

Te

I

100

92

85

85 At

Rb

Sr

Y

Zr

Nb

Mo

Tc

Ru

Rh

Pd

Ag

Cd

100

100

100

100

100

100

Nd

0

0

0

92

92

ord

W

Re

Os

IT

Pt

Au

Hg

TI

Pb

Bi

Po

69

0

0

0

0

0

36

31

100

31

ND

ND

Ttn

Yb

Lu

0

62

38

Cs

Bo

Lo

Hf

100

100

100

46

Fr

Ro

Ac

NO

NO

NO

To 62

Ce

Pr

Nd

Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

100

too

100

NO

100

100

85

85

85

77

77

Th

Po

U

92

ND

92

Figure 1. Occurrence frequency of elements in 13 raw coals as determined by spark-source mass spectrometry. All quantities in %. ND = not determined. Ο — checked but not detected. Η ND

Li

Be

4-163

0.4-

No

Mg

C

Ν

0

1-230

ND

ND

ND

Al

Si

Β

F ι- n o

3

100-

500-

3000- 5000-

1000

3500

2 3 , 0 0 0 41,000

Κ 3006500 Rb 1-150

Co

Sc

Ti

V

800-

3-30

200-

2-77

1800

6100 Sr 17-

Y 3-25

Zr

Cr 26-

Mn

Fe

Co

Ni

5-240

1400-

1-90

3-60

400 Nb

28-300 5 - 4 1

Ru

Rh

ND