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
