Document 99Yzoa8KaYDMy95ExgJvdaaqp
C O N S U M E Fi. T A L C U M S A N O P O W D E R S : M I N E R A L A N D CE! E MS C AL. C H A R A C T E R i Z A T I O N
A . N . R o h i , A . M . L a n g e iy 9. j . S c l i k o f f , A .. T o r d i m ,
K S im e n tid is
b rw trp n m e n ia l S c ie n c e s L a b a r a L o ry , M o u n t. S in a i S c h o o l n f M e d ic in e , o f th e C ity U n iv e r s ity o f N e w Y o r k N eve Y o r k , N e w "York.
D. R . B o w e s, D , L , S k in n e r
O e p a rfm e n i. o f G e o lo g y * T h e U n iv e rs ity o f G G la s g o w , S c o t!a n d
Represen ta live consum es; taiccirns arid powders-, in clu d in g 2 0 b o d y p o w d e ry betby powders,, facto ! i&iCLi-fnx, a n d a ls o o n e ph arm aceu tical! Ca!c3 were a n a ly z e d 'to determ ine, their d vr/erafagfcai an d cherniepf co m position,. Where, known-, a ll were fo rm u lated prior to 7.973V O f thtr. 2Q.p-res.de/cts if) c o n ta in e d d e te ctab le am o u n ts o f trem olivc a n d am hophylllte, principally asbestifoirn? while so m e also contained- fragm ented form s o f those m inerah , The. o ox? tin ts ra n g e d f r o m ten th s o f a p erce n t So oyer 14% by weigh 0 two contained detectable am o u n ts o f' ch rysolite asb esto s fiber; Eight contained quartz, seven ranging from 2 to 5%, with one as high as 33% , The analyses show ed' th at the. consum er p ro d u c ts ex am in ed were rarely the p u re m ineral talc, but rather were m ixtures o f various; m inerals* so m e sam p les co n sisted o f th ree to five minerals, only one o f which was talc. O ther co m m on m ineral ph ases Included chlorite, platy seepgn ripe? pyrd-phy llite 9 mlcct, a n d ' pardon trie m inetp li. K a p tlp additive- was- id en tified in tw o p ro d u c ts. The sin g le p h a r m a c e u tic a l info, e x a m in e d contained, only a trace am ount o f quartz..
The chem ical com position o f these pro ducts, including bo th m ajo r oxide and trace element content^ correfatted with their mlherul Compoment.z. Four sampled contained
su bstan tial concerntrationr. o f inichei, cobalt, an d chrom ium , su ggestin g lattice, su bstftid tfgn o r th e p re se n c e o f tra c e m in eral phases. G e o lo g ic al prove p an e ?. o f the talcs m ay be. a sc e rta in e d o n th e basis o f ch em istry . P ossible ad v erse health effects, from ' interm ittent: use. o f th ese p rod ucts, especially those, th at contain ersbestiform and. frag m en ted a n th ap h y H ite a n d trem olrte, ch rysotslc, q u artz, <ind trace m etals, are presently sjnhnown and warrant eyeHisgtlpm
IN TR O D U C TIO N
C onsum er ta lc u m s and pow ders; are considered: b y th e general p u b ile to be tide, an im p re ssio n [ha t is c o n v e y e d and s tre n g th e n e d by the p r o d u c t
T h is s t u d y was s u p p o r te d in p a ri, b y grani: ES 0 0 9 2 8 (ro.rn th e N a tio n a * in s a U u te o f h v I r o n m e h i i R e a lt S c ie n c e s . O n e o f u s { A M L ) r'&GAlVfed r a p p o r t u n d e r C a re e r S c ie n tis t A w a r d ES 44:8 1 2 :, N a tio n ! i n s t it u t e o f C rrv iro :ro v e n ta i H c!?b S c ie n c e s ,
R e q u e sts for reprints sh o u ld be sen t to A,.. ft, l t i fri, Lstytfoirs m eritai S cien ces L ab oratory , M ount Sinai ScbooS o f Medicine nr the C liy University o f New York, New York, New-York '0 0 2 9 .
255-
Jo urna: o f ToYfcoiogy an d nviron.mrt.! HeaStli, 2: a5 5 " 2 8 4 s 1 9 7 5 C o p y righ t > 1 9 1 6 b y 'Hemisphere. Publishi ng C o rp o r a to r !
PLAINTIFF'S E X H IB IT
WCD-102
CPC-BCALTRSCPT00000334
256
A . M. R O H L ET A L .
names and ingredients listed o n the container labels. H owever, know ledge
o f the geological occurrence and m iners logical character o f source
materials suggests the nature o f talc to be h ig h ly variable and co m p le x.
T w e n t y - o n e c o n s u m e r ta l c u m s a n d p o w d e r s ( T a b l e 1) w ere m in e ra logically
and ch e m ica lly analyzed to d e te rm in e w h e th e r these p ro d u cts are actually
talc mineral.
T a lc is a d e f in e d m in e ra l e n t i t y , based o n specific c h e m ic a l, crystallin e,
and physical p ro p e rtie s ( F o rd , 1 9 5 7 ). T h e e m p iric a l chem ical fo rm u la ,
M g 5 St* O ( O H ) , , Is s e l d o m o b s e rv e d in n a t u r e as a r e s u lt o f c a t i o n
s u b s t itu t io n . F o r e x a m p le , m agnesium is f r e q u e n t l y replaced b y iro n ,
n i c k e l , c h r o m i u m , o r m a n g a n e s e i n t h e c ry s ta l s t r u c t u r e . T a lc is a sheet
silicate, with a s tru c tu ra l u n it co n sistin g o f three layers; a sheet o f
o c ta h e d ra lly c o o rd in a te d m agnesium h y d r o x id e groups is sandw iched
betw een tw o layers o f te tra h e d ra lly inked silica layers. The Van der Waals
bon d b etw een th e talc sheets are o f lo w en erg y ac c o u n tin g fo r th e ease
w ith w h ic h ta lc as w e ll as o th e r sh eet s i li c a t e m in erals (m ic a s , cla y s ) cleave
T A B L E . 1 . D e s iig r ia fic n o f C o r . t e r n s 'in B ra .o rf N s .m e o r
Label
Sample
ITO.
D a te o f fo ririL ila ts o n
Products designated as talcs
3 N o t a v a ila b le a N o r a v a ila b le 1 2 A p p ro x im a te ly 39 7 2 7 S e p te m b e r 1 972 t 7 W ot v a ils b ic S A p ril IS , 1973 79 May 1973 2 3 N o t a v a ila b le
SVoducts
4
20 $
E6
as p o ld e r * tale ori tabe!)
Daccmbsc 1 970
Not avaSSabS*
i) w .e m b r 39 7 0
F e b re ja ry 1 9 7 3
Nofc avaiEabie
P ro-ilueLu d e s ig n a te c i ss p o w d c rs (otr -d;jst)
1 B e w e e rj Jaciw ary 39 6 5 ar. ju d y 1 9 7 0
14 O c to b e r 3, 1 9 7 0
- 15
Eetw-esn G r-to b e r 1 9 7 0 a n d M arch* '9 7 3
9 F f ib r u a ir y o r .Wafer 1 9 7 3
11 ju 'ry 1 9 6 9
I 3 $vi!y 3 6 , I 9 7 0
2 N o t a v a 13a b le
1C A p p r o x i m M e i y 1SS7 2
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or break in to platy fragm ents. This facile cleavage, w ith resultant high surface area, and its softness, sm all particle size, arid whiteness confer u p o n Laic its u s e fu ln e s s as a c o s m e t ic m a t e r ia l.
g e o l o g ic a l o c c u r r e n c e o f t a l c
Talc rocks (in c lu d in g those c o m m e rc ia lly w o rk e d } are fo rm e d by several co m p le x geological processes reacting upon m a n y possible, chem ically diverse preexisting- rock types. H y d ro th e rm a l a lte ra tio n o f magnesiaand silica-rich u itra m a fic rocks, u n d e r a range o f io w -to -m o d e ra te tem pera tures and pressures,, m a y p ro d u c e la ic. T h e rm a l m e ta m o rp h is m o f silicar i c h d o l o m i t e [ C a M g ( C 0 3 ) , J w i l l p r o d u c e ta lc as w e ll. T h e se processes, how ever, also c o m m o n ly result in the fo rm a tio n o f a n u m b e r o f other coexisting' m ineral phases, p re d o m in a n tly h yd ro u s m agnesium silicates. S om e o f these, fo r e xa m p le , a n th o p b y M ite , tre m o lite , and serpentine m in e ra ls (in c lu d in g c h r y s o lit e ) , o c c u r as m ic r o s c o p ic in te r g r o w t h s w it h ta lc , as m a c r o s c o p ic n o d u le s , o r even as d is c re te z o n e s w i t h i n o r a d ja c e n t to ta lc (T a b le 2). T a lc r o c k is t h e r e fo r e g e n e ra lly n o t m o n o m in e r a ilic b u t is o fte n a m ix tu r e o f m in e ra ls th a t m a y vary w id e ly w it h respect to k in d and q u a n tity . Phlogopite, a magnesium m ica, and ch lo rite , a group o f m inerals related to the micas, are also c o m m o n ly associated w ith laic. Som e o f these associated m in e ra l phases are a sb e stifo rm a m p h ib o ie s and c h ry s o lite (see d iscussion o f th e te rm s asbestos and a sb e s tifo rm in A p p e n d i x A ) . C o n v e r s e l y , l a i c has b e e n d e s c r i b e d as a c o m m o n a cc e s s o ry m ineral in com m ercial asbestos deposits (H u rib u t and W illiam s, 1935).
Talc deposits m ay be zo n e d , w ith d iffe re n t m ineral assemblages physically changing in occurrence and p ro p o rtio n s over e xtre m e ly variable
T A B i . 1 . M m e rJ tis t h a t C o r n m o r iJ y O c c u r Jn T a lc D e p o s it s
Mineral group
Formula
Carbonates
A m p h ib o ie s S erpen "nc
O thers
Calcftc DoSoftuir Magne^ht
T r e m o : i t e tf A at ho p h y I!itea
A rttig o rrie C hrysotM e (u n c o m m o n 1 L iza rd ite [u n c o m m o n )
Q u artz M ica, e-g.. C h lo rite , -g., p e n rifn lie P y ro p fty liiie
C aC 03
Ca-M^COj},
M gCO a
O l, M g , 5 1 * 0 , , ( O H J ,
FeMg), S i.O ^ iO H ),
M g .* S i s <J>3 [ O r t h M g , S i, O , (O H ). M g , Si.O , ( O H ) .
SIO,
K , ( M g , F t ) , [ S i . A i , O ae i ( O H ) , (M g .A I,,= = ),, ilS i. A I ) , O m i (O H ) ,6
Ai, [(S I.O ^jlO H h
^ o c c u r r in g 5 f ib r o u s a r-d r .o rtfib fo v jis f o r m s . O t h e r t r a c e m in e r a l p h a s e s ar*. o f reft pres-erit b u t are n o t In c lu d e d .
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A N. R O W . ET A L .
distances, ranging fr o m ce n tim e te rs to tens o f m eters. Miners? phases in su c h d e p o s it s m a y i n c l u d e t ale p i a ie s a n d f i b e r s , t r e m o i i t e a n d a n t h o p h y l -
lite fibers, intergrowth's o f am p b ib o le and talc, serpentine m inerals (w hich m ay include chrvscitiie), and free silica (q u a rtz) (Ross et aL, 1968), The f i b e r i n t e r g r o w t h as o f t e n su c h t h a t even e x t e n s i v e b e n e f i c i a t i o n m a y n o t yield a pure - p ro d u ct. T hus, where fine-grained in te rg ro w th s o f talc and tre m o iite occur, the processed p ro d u c t w ill like ly co n ta in residua! tremohie. Further details concerning the crystal chem istry, structure, synthesis, and geological occu rre n ce o f talc are fo u n d in A p p e n d ix 8.
IN D U S T R IA L A N D COSM ETIC G R A D E TALC S '
it is generally recognized th a t various c o m m e rc ia l grades o f talc are m a rke te d in th e U n ite d S tates ( A p p e n d ix C). H ild ic k - S m ith (1 9 7 6 } has stated that a talc suitable fo r pharm aceutical purposes, used in cosmetic a n d t o i l e t r y p r o d u c t s , c o n t a i n s a t least 9 0 % ta lc r n in e r a i 3.nd n o d e te c t a b le asbestos. Such stated co m p o s itio n a l restrictions are n o t placed on indus tria l grade talcs. O ne stu d y d e m o n stra te d th a t a n u m b e r o f in d u stria l talcs contained substantial quantities o f tre m o iite , up to 87% by w eight o f the sample (Schulz and W illiams, 1942).
In 1968, a stu d y (C ralley et aL, 1968) o f 22 cosm etic talcum products demonstrated fiber contents ranging
fr o m 8 to 30% b y c o u n t w ith an average o f 19%. T h e fib ro u s
m aterial was p re d o m in a te ly talc b u t p ro b a b ly contained -m in o r
a m o u n t s o f t r e m o i i t e , a r s t h o p h y ll s t e a n d c h r y s o t i l e as th e s e are
o fte n present: in fib ro u s talc m ineral deposits.
W ith the exception o f 4 o f the 22 cosm etic talcum products
analyzed, the levels o f free silica, c o b a lt, n ic k e l, c h ro m iu m , and
manganese were generally o f a lo w m agnitude and w ith in a
n a rro w range. , . . T h e levels o f silica, c h ro m iu m , and nickel in
these fo u r p ro d u c ts are s u ffic ie n tly high, how ever, to be o f
concern in th e ir p o te n tia l to cause disease.
...
T h u s , as la te as 1 9 6 8 s o m e c o n s u m e r t a l c u m p r o d u c t s m a r k e t e d in th e U n ite d States contained asbestiform m inerals, free silica, and trace metals.
H U M A N DISEASE A S S O C IATE D W ITH TALC EXPOSURE
F o r nearly h a lf a ce n tu ry a num ber o f reports have show n that o c c u p a tio n a l e x p o s u re to talc d u s t is associated w it h a fin e d iffu s e i n t e r s t i t i a l lu n g s c a r r in g k n o w n as ta lco sis. F i b r o u s ta lcs ap p e a re d to be m ore pathogenic than platy talcs, producing in a d d ition to talcosis, increased risk o f m alignant tu m o rs in exposed w orkers (K leirifeld and
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CONSUMER TALCUMS A N D POWDERS
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Mcsstte, 1 9 6 0 ; K lcinfefd et ai., 1 9 6 7 ). S tu d ie s c o n c e rn in g th e b iolgica! consequences associated w it h taic d u st e x p o s u re , including cancer, are referred to in A p p e n d ix D.
O BJECTIVES OF THE PRESENT S TU D Y
T w e n ty-o n e samples o f consum er talcum s and pow ders. including baby p o w d e rs , b o d y p o w d e rs, facia! pow ders, and a pharm aceutical ta lc u m , were o b ta in e d at retail stores in the N e w Y o r k C it y area. These samples 'were acquired and studied d u rin g the period 1 9 7 1 -1 9 7 5 {Table !}. The m ajor purpose of the s tu d y was to d e te rm in e the mineraSogical and chemical co m p o s itio n , w ith p a rtic u la r em phasis on th e q u a n tita tiv e d e te rm in a tio n o f tre m o iite , a n th o p h y llite , serpentine m inerals, and q uartz. A n o th e r o b je ctive was to establish a base line fo r consum er talcum s and pow ders, based o n a s a m p lin g o f p ro d u c ts available d u r in g th e p e r io d 1 9 7 1 - 1 9 7 5 , T h is base line provides an ndex fo r e va lu a tin g possible changes in subsequent fo r m u lations.
M ETHO DO LO G Y A N D RESULTS OF M IN E R A L A N D C H EM IC AL C H A R A C T E R IZ A T IO N
T h e analytical techniques e m p lo y e d fo r m ineral id e n tific a tio n and q u a n tific a tio n included o p tical m icroscopy, transm ission electron m icro scopy w ith selected area electron d iffra c tio n , X -ray d iffra c tio n , and scanning electron m icroscopy w ith X -ra y analysis capabilities, C hem ical determ inations (b u lk chem istry and trace metals) were made w ith a num ber o f standard in s tru m e n ts and geochem ical tech n iq u e s, including s p e c tro p h o to m e try [S i0 2 , TOa , A ! , 0 3 , total Fe {F e2 0 3 by difference f r o m F e O ), P2.O s J ; a to m ic a b s o rp tio n ( M n O , M g O , C a O ) ; fla m e p h o t o m e t r y (N a 2 0 , K 2 Q ) ; w e t ch e m ic a l assay (F e O ) ; w e ig h t loss, volatiles { H 2 O , C O ; , organics). X -ra y fluorescence was used fo r all trace metals (Bowes and Langer, 1974).
Optica! M icroscopy
.
O p tic a l m ic ro s c o p y is a c o n v e n tio n a l te c h n iq u e fo r th e id e n tific a tio n o f m inerals and fo r th e s tu d y o f m inerai relationships. A m icroscope e q u ipp e d w ith b rig h t field illu m in a tio n and p o la rize d lig h t o p tics was used to analyze the cosm etic pow ders. A p p ro x im a te ly 0.5 mg o f p o w d e r was p laced on a p reclean ed glass slide an d im m ersed in in d e x o ils o f kn o w n refractive indices. These w ere checked on a re fra c to m e te r. T h e in fo rm a tio n o b tain ed on p a rticle s w ith this m e th o d in c lu d e d m ost o f the m easurable o p tic a l p ro perties, in c lu d in g indices o f re fra c tio n , e x tin c tio n angles o f fibers, general m o r p h o lo g y , and size characteristics o f m ineral phases {F ig . 1 ). tn coarse-grained pow ders, fibers c o u id be id en tified (tre m o iite , a n th o p h y llite , ta lc ). T w o samples c o n tain ed co rn starch , easily recognized
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CONSUMER TALCUM S AN D POWDERS
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by m orphological and optical characteristics. O ne p ro d u c t consisted
entirely o f cornstarch.
_ . ..
In m ost sam ples, how ever, the p o w d e rs were to o lin e graineo, w ith
p a rtic le d im e n sio n s S ignifican tly less th a n 1.0 p m , fo r th e te c h n iq u e to be
useful. The lim itin g factor for d e te rm in a tio n o f optica! constants, and
hence fo r 'id e n tific a tio n o f p a rticle s, is th e resolving p o w e r o f the microscope. T he presence o f talc fibers, which may have indices o f re fra ctio n sim ila r to a m p h ib o le (tre m o lite , a n th o p h y liite ) fibers, also
c o n fo u n d s analysis. T h e re fo re , a lth o u g h th is te ch n iq u e is an exce lle n t d ia g n o s tic i n s t r u m e n t trt s o m e in s ta n c e s these r e s t r ic t io n s lim i t e d its
useful ness. O th e r investigators have experienced sim ila r d iffic u ltie s . F o r example,
in a s tu d y o f the asbestos c o n te n t o f ta lc (S ta n le y and N o rw o o d , 19 7 3 ),
there was d iffic u lty in applying optical m icroscopy to the problem . The
authors concluded th a t optica! m icroscopy
w hile it w orks well on pure sam ples of fa irly massive fib e r length fro m 3 to 5 m icrons, o u r observations by transmission e l e c t r o n m i c r o s c o p y h ave s h o w n t h a t n a tu ra lly o ccu rrin g asbestifo rm m inerals o fte n Ha b e lo w the w o rk in g re so lu tio n capabilities o f the light, m icroscope a n d f u r t h e r m o r e w h i l e m a s s iv e f i b e r bundles can o fte n be observed by either lig h t o r electron m ic r o s c o p y the. o b s e rv a tio n o f in d iv id u a l fib e r s s m a lle r th a n 0.5 by 0.2 m icrom eters o ften w ill require the high resolution ca p a b ility o f the transm ission electron m icroscope (emphasis added).
i t is fu r th e r stated th a t 'Might m ic ro s c o p y was h e lp fu l o n ly in screening samples w ith large particles and high co n ce n tra tio n s o f objectionable fibers."
B y com paring, the results o f optical m icroscopy w ith those o f quantita tive X -ra y d iffr a c tio n and e le c tro n m ic ro s c o p y , we observed th a t large numbers of fibers go undetected. In a d d itio n to the restraints o f resolution im posed by light m icro sco p y, a n o th e r m a jo r draw back relates to the strong tendency' o f asbestiform m inerals to cleave o r break along planes o f weakness w hen they are crushed, p ro d u c in g large num bers o f small fibers. F o r e xa m p le , lig h t m ic ro s c o p ic e x a m in a tio n o f a talc sam ple (no. S), w h i c h c o n t a i n s o v e r 1% t r e m o l i t e (see T a b l e 4 ) , d e m o n s t r a t e s th e p re s e n c e o f m ineral fra g m e n ts th a t are p rim a rily ' n o t a sb e stifo rm (F ig. 1C). H o w
ever, ele ctro n m icroscopic e x a m in a tio n o f the same sample dem onstrates th a t m a n y o f th e s u b m ic r o s c o p ic t r e m o l it e p a rtic le s are fib r o u s (see Fig. 3E). The problem involving the d e te rm in a tio n o f the relative proportions o f each o f these m o rp h o lo g ic a l phases in th e same s a m p le (mass vs.
n u m b e r ) is p re s e n tly u n re s o lv e d . B a s ic a lly , th e large fib e rs are b ro k e n d u rin g m illin g y ie ld in g a n ew size d is trib u tio n in th e s u b m ic ro s c o p ic range.
CPC-BCALTRSCPT00000340
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A . N- R O H L ET A L.
X-ray D iffraction
T h e a p p lic a tio n o f X -r a y d i f f r a c t i o n analysis in step-scan m o d e f o r q u a n tita tiv e d eterm in atio n o f asbestos in la ic has been described in detail {R o h l and Langer, 1 9 7 4 ), in c lu d in g the selection o f talc and asbestos reference m aterials, the preparation o f standard dilutions o f asbestos m inerals in talc to ensure se n sitivity and re p ro d u c ib ility , the selection o f characteristic X -ray re fle ctio n s to be scanned, and in s tru m e n ta l technique.
Selection o f talc m ineral standard. S c re e n in g o f v a rio u s ty p e s o f talcs f o r use as r e f e r e n c e m a t e r i a ! w a s m a d e b y X -ra y d iff r a c tio n and trans mission e le c tro n m ic ro s c o p ic analysis. A c o n tin u o u s scan was fir s t m ade to
id e n tify the m a jo r m ineral phases p re se n t. Talcs th a t show ed the presence o f a n y s e r p e n t in e m i n e r a l , t r e m o l i t e , o r a n th o p h y iiite w e re e l i m i n a t e d as
reference m aterials. T h e possibility o f false negatives for these minerals was checked by step scanning the diagnostic reflections {Table 3 ). F urth er v e rific a tio n o f th e absence o f asbestiform m inerals was m ade b y trans mission e le c tro n m ic ro s c o p y . These te c h n iq u e s p erm itted the selection o f a
m atrix talc th a t was c o m p le te ly free o f asbestiform m inerals. C h lo rite m inerals are hydrous iron-m agnesium silicates, fre q u e n tly
associated w ith talcs. T h e ir presence m a y interfere w ith the d e te c tio n o f s e r p e n t i n e m in e ra ls , b o th p i a t y (a n tig o rite ) an d fib ro u s (c h ry s o tile ). T h is is p a rtic u la rly tru e if th e y are present In equal o r larger a m o u n ts than these la t t e r m in e ra ls. T w o in te n s e basal re f le c t io n s a t 1 4 ,2 A (0 0 1 ) and 7.1 A (0 0 2 ) are characteristic o f c h lo r ite m inerals. T h e la tte r re fle c tio n occurs close to the (002) reflection o f serpentine minerals (7.3 A). T he 3.66 A (0 0 4 ) r e f l e c t i o n o f s e r p e n t i n e w as s e le c te d as d i a g n o s t ic ( T a b l e 3 ) , since t h e lo w e r in te n s ity (0 0 4 ) re fle c tio n o f c h lo rite ( 3 ,5 3 A ) in this r e g i o n was fo u n d n o t to cause interference.
Selection o f the asbestos standard. R e fe r e n c e s a m p le s o f p u r e asbestos m inerals were o b ta in e d fr o m various m ineral collections and fr o m the International A ssociation fo r Research on Cancer (IA R C }. These were screened fo r p u rity and p a rticu larly fo r the presence o f in te rfe rin g contam inants according to the procedures previously described fo r talc. T w o d iffe r e n t sp ecim en s o f c h r y s o t i l e w e re used as re fe re n ce m a te ria ls : a trip le air-jet m illed sample fro m the J e ffre y M ine, Q uebec (p ro v id e d by th e joh n s-M an viiie C o rp .) and a specim en fr o m Ooalinga, C alifornia (provided by the C alidria Division, U nion Carbide C orp.).
Sample preparation. .A m o n g t h e v a ria b le s t h a t s t r o n g l y i n f l u e n c e th e
precision and accuracy o f q u a n tita tiv e X -ra y d iffra c to m e try are pa rticle size, preferred o rie n ta tio n , and surface flatness. V a ria tio n due to particle
size can be m in im iz e d b y cru sh in g an d screening t h e asbestos and talc-
s ta n d a rd s to ensure a u n ifo rm size d is trib u tio n , w ith an e ffe c tiv e crystallite d i m e n s io n o n th e o r d e r o f 5 u rn o r less. T h e e f f e c t o f p re fe rre d o r ie n ta tio n is m o re d i f f i c u l t to control.. T h e te n d e n c y f o r preferred
o rie n ta tio n is la rg e ly th e fu n c tio n o f m in e ra l cleavage p ro p e rtie s . B oth the talc a nd the asbestos m inerals have e xcellen t cleavages, p ia ty in talc and
CPC-BCALTRSCPT00000341
- CONSUM?.!* T A L C U M S A N D PO W DlR S
263
T A i L E 3. O O b fa U a n C u rv e D a la fo r th e O c ie rn n jria v io n o ' A ib c s !f e n n M in e ra l^ 2 n d Q u a r u
in Talc by X-ray A nalysis*'
M in e ra l phase
Pqu^rnef-ttr
A V 'b c jp h y /itc C h ry s o c iic
0 1/ a r t x
M l f r*<3** o f cjL a g r.o silc r ^ fe c iiQ n C r <?s p o n d i n g { /- s p a c in g { A ) R e s a tiv k it errs-'ey S t-c p -s c a n jni<3.rva< ( 2 th e i- a )
C21 0 J S .26
55 10 -0 -1 1,0
004) 3.G 6
m 2 3 .5 -2 5 .0
i'J: 1 1 1,5 4
15 5 3 .5 -6 0 .5
P e rc e n t m in e r a ! in t.ale an d c o r r e s p o n d in g a rc o r e f ic c t o /i
1 fe m o liif
(1 1 0 ) 8 .3 8 100 1 0 -0 - 1,0
A n th o p h y ilite
%
5 .0 1 0 .0 T 5.0 2 0 .0 2 5 .0 3 0 .0 3 5 .0
~
n .3c
0 .5 2 2 .3 5 3.9 9 4 ,6 5 5.1 2 7 .2 2 9 .9 2
-
C h ry s o lite
% in .*
0 ,2 5 0 ,5 1 .0 2 .0 5 .0 7 .0
8 .5 S.9
0 .0 1 0 .0 3 o.o s 0 .2 2 0 .9 4 1.5 7 2 .2 1 2 .3 4
QlMTiZ.
% in ,*
5 .0 1 0 ,0 2 0 .0 2 5 .0 3 0 ,0 4 0-0
--
7..75 3 .7 5 7.1 1 9 ,3 0 1 3.2 0 1 6 .9 0
--
...
T re m u lls
% in .3
0-1 0 .5 2 .2 7,7 4 .3 5 .0 7 .0 1 0,0
0-1 3 0 .3 0 0.4 3 C .S 7 1 .2 5 i.s s 2.03 2 .8 0
Di?*cl!ori limit
W t % A n th o p h y K fte - A rea (2 T 0 ) ~ C .2 7 (< & A ri5 ~ 0 .5 2
W't % C h r y s o t it e
- A r o s ( 0 0 4 5 =* 0 . 2 7 ( C h j -- 0 . 5 0
V i-% Q u a rz
- A r o 1211) = 0 . {% Q } - 0 .6 0
W t % T rn w iile
a. A rea 1T0) = 0 .2 8 !% 7 rj _ 0 .0 4
R :c -- 0 . 5 5 R * = 0 . 9 8 R ' - 0 .9 6 R * = 0 .0 8
7.0% 0 .7 % 1 .4 % 0 ,1 %
?!i`!sr,rija rse rjr? .l t i r
i,v:; /'V i i - C t ; / M s , 4 5 k V / 2 0 t r t A j s c in t i S I d li o n c o u n e r , 1 4 5 0 V D C ;
.rt'.o ro ^ ifc m a ^ r, g ra p h ite ;
a n a ly z e r , 2 0 V , 5 V L ^ i t t h , t e v ^ l ) ; c o n t in u o u s s-c-ar, T '
2 0/mJn; step-scan, 0.02 2 e at 2,000 counts Rxee.
^Rhombo^era inti ex.
^ R e p e a te d (ncason-cmcintji o f arcas- u n d e r c u rv e s w it h a p o la r p i a n i m e te r in d ic a t e d a v e ra g e
d e v i a t i o n o f * 0 . 0 2 --0 . 0 5 fr> A .
f i b r o u s in She case o f t r e m o f i t e , a n t h o p h y l l i t e , a n d c h r y s o l i t e (see R o h l and Langer, 1974, Fig. 2). In a tte m p rin g to reduce or elim inate the effects o f preferred o rie n ta tio n in X-ray analysis, a n um ber o f sample preparation and in s tru m e n ta l te c h n iq u e s have been developed (Bragg., 1 9 6 7 ; B rin d le y and K urtossy, 1 9 6 1 ; C u liity , 1956; K iu g and A lexander. 1954). In the present stu d y these techniques were tested, b u t none was fo u n d to provide adequate precision (re p ro d u c ib ility ). A cco rd in gly, a sample preparation tech n iq u e was developed th a t was successfully used, in c o n ju n c tio n w ith X -ray d iffra c tio n in the step-scan m ode, to detect diagnostic reflections o f these m inerals in a talc m a trix over a range o f co n ce n tra tio n s (Table 3).
CPC-BCALTRSCPT00000342
254 A. N. R O H L ET A t .
The re p ro d u c ib ility o f reflection intensities was also greater than other preparation techniques tested.
Binary d ilu tio n standards o f c h ry s o lite , a n th o p h y liite , and tre m o lite in talc were prepared gravtm etrically, Asbestos fiber concentrations were prepared in itia lly at 5.0, 4.0, 2.0, 1.0, 0.5, 0.2, and 0.1%. F ifty milligrams o f th e ta lc -a s b e s to s m i x t u r e s -were h o m o g e n iz e d in I O m! f i l t e r e d w a te r u tiliz in g ultrasonic energy. This slurry was poured in to a 30 cc Syringe and filte re d th ro u g h a 0 .2 2 jjm pore size m em brane filte r. T o prevent s tra tific a tio n due to d iffe re n tia l p a rtic le size and density effects, the s y rin g e is h e ld in a h o r i z o n t a l p o s i t i o n , r o t a te d , a n d sh a k e n d u r in g filtra tio n . The residue form s a fla t cake o f about 0.5 m m uniform th ic k n e s s o n the m e m b ra n e filte r . W h e n d rie d , th e sam ple is a ffix e d t o a glass slide fo r X -ray d iffr a c tio n analysis (R o h l and Langer, 1974).
Selection o f X -ra y reflections. Because o f c r y s t a l s t r u c t u r e s im ila r itie s in the minerals being s tu d ie d (i.e,, tre m o lite and a n th o p h y !b ite }, consider ate e overlapping and interference o f X-ray reflections occur. T he low sym m etry and consequent com plex X -ray diffractogram s o f such minerals as t a l c , c h l o r i t e , a n d m i c a , as w e ll as p o s s ib le i n t e r f e r e n c e s f r o m a d m i x e d phases s u c h as k a o l i n i t e , m a k e i t necessary t o s e le c t a r e f l e c t i o n or set o f r e f le c t io n s f o r each m i n e r a l c o m p o n e n t th a t c o u ld be used as an in d e x o f the am ount o f that m ineral in a m ix tu re . Such diagnostic reflections were selected by referring to standard X -ray pow der d iffra c tio n data. These diagnostic re fle c tio n s were step-scanned a t 0 .0 2 2 theta in a fix e d c o u n t m ode (2 X 1 0 3 c o u n ts ). Precise p o sitio ns and p ro file s o f the diagnostic reflections were determ ined. In the fixe d co u n t m ode, each o f the angular intervals selected are scanned w ith equal accuracy. Thus weak reflections can be d e te r m in e d w i t h eq u a l p re c is io n as h ig h i n t e n s i t y re fle c tio n s . T h e statistical accuracy depends o n ly on the total num ber o f counts recorded, and the c o u n tin g rate selected gives a percentage probable e rro r o f about 2%. P r o file s o f th e d i a g n o s t i c r e f l e c t i o n s , p l o t t e d as a f u n c t i o n o f n u m b e r o f c o u n ts vs. 2 th e ta , are measured w it h a c o m p e n s a tin g p o la r pianirrieter. T h e in te n s ity o f a r e f le c t io n is p r o p o r t i o n a l t o , but: n o t necessarily a lin e a r fu n ctio n of, its concentration. O ther factors th a t m ay influence reflection intensities include in s tru m e n ta l c o n d itio n s , particle size, degree o f p re ferred orientation, sam ple thickness and flatness, and absorption character istics (KJug and A le xa n d e r, 1954; R ohl and Langer, 1974),
Figure 2 shows calibration curves obtained fo r chrysotile, anthophyilite , tre m o lite , arid q u a rtz using th e step-scan technique. Measured areas o f diagnostic reflections are p lo tte d against percent d ilu tio n in talc. As i n d i c a t e d in T a b le 3 t r e m o l i t e m a y be d e t e r m i n e d a t levels as l o w as 0 . 1 0 % b y w e i g h t , c h r y s o t i l e f r o m 0 .2 5 to 0 . 5 0 % , a n d a n t h o p h y i l i t e , as l o w as 2 % in talc. I t is I m p o r t a n t to n o te t h a t th e lim it s o f d e te c t io n given in Table 3 are h ig h er and based on a best f i t regression analysis. For exam ple, regression analysis indicates that the detection lim it fo r chryso lite is 0.7 % , w hereas f r o m 0 .2 5 to 0.5% can be a c tu a lly detected.
CPC-BCALTRSCPT00000343
Ares,
CONSUMER TALCUM S A N Q POWDERS
26 S
F i G U R E 2 . o a U b r a t i o n o a s b e s t i f o r m a m p h i b o le s a n d Q u a r t? iv> ta ie .
d e p e n d in g on p a rtic le size, degree o f c r y s ta llin ity , etc. T h e change:; in slope at the lo w e r end o f the curves are n o t reflected so th a t axial in te rc e p ts are exaggerated on the high end o f the abscissa.
B y u s in g X - r a y d i f f r a c t i o n 1rs th e s te p - s c a n m o d e , S t a n l e y a n d N o r w o o d {'! 9 7 3 ) w ere able to d e te c t a m in im u m o f 0 .2 5 % tr e m o iit e irt taic and a m in im u m o f 0.5% ch ryso tiie and the oth e r asbestiform minerais. H ow ever, such lo w levels o f c h ryso tiie were n o t detected when chlorite was present.
Step scanning. T h e c o n t e n t s o f the c o n t a i n e r s w ere th o ro u g h ly m ix e d w ith a sample sp litte r to avoid stra tifica tio n effects. A liq u o ts o f each, w e ig h in g 5 0 trig, w ere prepared using the id e n tica l m e th o d o lo g y described f o r p r e p a r a t io n o f th e d i l u t i o n standards. T h e filte r-m o u n te d sam ples were, th e n step scanned o ve r th e g o n io m e tric intervals diagnostic fo r the standard asbestiform m inerals and q u artz. Instrum ent operating conditions were identical w ith those used fo r analyzing the d ilu tio n standards. Profiles p lo tte d fo r the d ia g n o s tic intervals and reflectio n areas after peak stripping were m easured by p o la r p la n im e try . T he w eight percents o f a n th o p h y llite , tre m o iite , and q u a rtz contents were estim ated b y referring to the a p p ro p riate regression curve. I he q u an tities o f asbestiform m aterials in th e 21 talcum s and p o w d e rs f o u n d b y this te c h n iq u e are show n in T a b le 4. T h e results show th a t 1 0 o f the 21 samples c o n ta in am phibole
CPC-BCALTRSCPT00000344
3? O. I 1 I 3= o~ : I i !
! i I
a_ a. I | ]
O os/
1f i I
Lf ! i I I
S o, i. o- l ^ I I
g a- <x c._ i \ l i
! i ! ! 5!
*- J L I _ "T --<7f' [ 5~
S a. I i
'_ O- X Ci.
CJN
3= J~fr-- ' I * 5 ^ a. i i f i
-,- i r ! 2 i
5!
o 'c
s-- * icrr -3zs-
5 C O o s rL
o c> o }. (.jex c~Ci- "U5
CO
OJ='2- it'-. r'_-
|<-
e d_
,
4 E vT l-1 &
166
CPC-BCALTRSCPT00000345
co nsum er talcu m s an d pow ders
:?6 7
m in e r a is, ra n g in g in a m o u n t s f r o m a f e w te n th s o f a p e rc e n t t o o v e r 14%. T re m o lite was the m ost c o m m o n ly fo u n d (9 o f the 2 1 ), and a n th o p h y llite occu rre d w ith tre m o lite in 6 o f the 21. A serpentine m ineral phase was in d ic a te d in tw o samples, in a m o u n ts at or near the lo w e r lim its o f d e t e c t i o n . V e r i f i c a t i o n : o f t h e s e r p e n t i n e p h a se as c h r y s o t i l e in t h e t w o samples in am o u n ts corresponding to the observed concentrations was made by electron m icroscopy.
C ontinuous scanning. In o r d e r t o s t u d y th e presence o f all m i n e r a l g
ica! (and possibly o th e r crystalline) co m p o n e n ts the samples were scanned fro m 5 to 70 2 theta a t a scanning rate o f 1 2 theta per m inute. This t e c h n i q u e , as e x p e c t e d , p ro v e d s a t i s f a c t o r y f o r t h e i d e n t i f i c a t i o n o f m a jo r
co m p o n e n ts, bu t it was generally fo u n d to be incapable o f detecting tr e m o lite , a n th o p h y llite , or se rp e n tin e m inerals e xce p t in cases o f gross c o n ta m in a t io n . T h e h ig h noise level (low,' p e a k -to -b a c k g ro u n d ra tio ) o fte n p re v e n ts th e d e te c tio n o f q u a n titie s o n th e o r d e r o f 4 - 6 % o r less and also excludes this te chnique fo r q u a n tita tiv e analysis. As a result o f high noise level th re e fa lse p o s itiv e s , as in d ic a t e d b y c o n t i n u o u s s c a n n in g , w e re subsequently show n to be negative fo r a m p hibole by step scanning and e lectron m icroscopy. In a d d itio n , co n tin u o u s scanning may n o t generally
d e te ct serpentine m inerals in the presence o f ch lo rite o r kaolinite.
Electron M icroscopy and Electron D iffra ctio n
T h e tra n sm issio n e le c tro n m icro sco p e has been sh o w n t o possess the
sensitivity required fo r fib e r id e n tificatio n and fo r determ ination o f
p a rticle size d is trib u tio n o f subm tcroscopic particles (Langer and Pooley,
1973; Langer et ah, 1973) .
'
A c c o rd in g ly , aliquots o f talcum samples were prepared fo r electron
m icroscopic analysis by a technique lh a t disperses particles in a d ro p o f
n itro c e llu lo s e s o lu tio n on a glass slide. A second glass slide is placed o n
the firs t and the tw o are d raw n lig h tly apart, leaving a film . This
te c h n iq u e is in te n d e d t o m in im is e th e a lte r a t io n o f p a rtic le size d is t r ib u
t i o n . T h e f i l m Is m o u n t e d o n e l e c t r o n m i c r o s c o p e g r id s a n d s c a n n e d at.
m agnifications o f X 20,000.
M o rp h o lo g ic a lly , a m p h ib o le m inerals are generally q u ite dissim ilar fro m
o th e r silicate m inerals. B o th a n th o p h y llite and tre m o lite are re ctilin e a r,
o fte n w ith a m p h ib o le -ty p e step cleavage or, in fre q u e n tly , w ith prism atic
te rm in a tio ns. T re m o lite fibers tend to be electron dense and Shorter than
a n t h o p h y llit e {F ig . 3 ) , w h ile th e la tte r has a te n d e n c y t o be e le c tro n
translucent and to sh o w d iffra c tio n contrast figures (Langer and Pooley,
197 3 ),' Sheet silicate m in e ra ls (talc, c h lo rite , micas) lend t o be equi-
'.dimensional in shape, o fte n w ith pseudohexagonal outlines (Fig. 4). Curled
talc plates o r talc fibers on edge m ay superficially resemble asbestiform
m inerals, b u t selected area electron d iffra c tio n patterns easily distinguish
betw een the tw o (com pare Fig. 5 A , C, and D).
E le c tro n m ic ro s c o p y , in c o m b in a tio n w ith selected area d iffra c tio n .
CPC-BCALTRSCPT00000346
F irS U R E 3. T ra n s m is s io n e le c tr o n m ic ro g ra p h * s n o w in g ra n g e in m o rp h o lo g ie ,; ! c n a ra e s e rra tic * or a s b e s tife rm w e m o ik e r n d n tn o p h y llU e in u le . T h e e n tire fa n g e o f m o rp h o lo g ie ! v a ria tio n ? o b se rve d f o i these m in e ra s a o b s e rv e d in th e asbe stos s ta n d a rd s : re c iilin e a r fib e rs w ith p a ra lle l e n d s n d e d g e s ( A } ; s ;; y -c ir a y-;; o r:d > [ 0 / ; o n : r b b r d s d r o t r t n ih n s B o r n i ; i-r r b o d y , \ C i ; < v r v iiin : :? .f f ib e r W ith a m p h ib o ly c le a v a g e e n d ( O t ; h ig h S e n g lh -to -w id lb r a tio fib e rs (.>; fib e rs p r o tr u d in g f r o m in te rio rs o f ta lc prates ( F ). A ll o f these m o rp h o lo g ic a l v a ria tio n * a n d fo rm s t A - t ) nave been d e s c rib e d in a n t h p p h y lliie a n d ir e m o lk e a se b e sio s s a m p le s . T h e a m p h ib o le s tru c tu re w as c o n firm e d In a ii cases b y s e le c te d area e le c tro n d iff r a c tio n c h a va cie r it a iio n . Scads as m a rk e d . M ic ro g ra p h s o b ta in e d on i J E O l JE M 1 2 0 U w ith an a c c e le ra tin g v o lta g e at 1 2 0 k V .
&
CPC-BCALTRSCPT00000347
CONSUMER TALCUM S AND POWDERS
169
P T G U R E 4 . Trans?nii5.s:u'ri e is i.L
ir ilc a x ig ra p S i? o f t o ia 'is t- ilc i<ak s a m p le s >:c5r>posed p r i m a r i l y o f
p u t ? , w k h a n tic c a s io ria i large ta-lc f lb s v ( 8 k C ); :z\c w i t h m a n y
fib e rs (D 4 v S c a le A th e .'same in
( A ) .a n d - ( S ) a n d an { C ; a rid 0 - 0 * A U f l e e r e d a re a e P e c rru n c U f f r a c iio f s p a n e r n s . o b i a in e d o n r'ib a rs
y i e l d e d I b o i c c o n j i s i e n t f o r taf>: p is te s { s e e r i g . .`3, A s n d S ) . I n 4S t a l'i - c o n t a a r 'n g s a m p le s
(.xa^i-iKd dy ekcti'orj fnic'c-.'vcopy taPf grains tended fo range from 'IS ` o 0..*?. j^rrs ;n great:e:St
fjir P r i? ^ a r i, M ic r n g y a p f. o b t a i n e d o n <j j E O L j E M SSO U w i t h a n a c p ! e r a i io n v ijiL a g e a i 1 2 0 k V .
was used to v e r ify th e presence o f annphibole in the 10 sam ples s h o w n to be positive by X-ray d iffra ctio n . Electron m icroscopy, w hile not quantitative, also show ed that a m p h ib o le fibers were present in relative am ounts th a t c o rre s p o n d e d to th e ir p erce n ta g e s as s h o w n b y X-fay d iffr a c tio n .
T he presence of traces o f chrysolite, rather than p ia ty serpentine, in sam ples 12 and 15 was v e rifie d by e le ctro n m ic ro s c o p y {Fig. 6), By
CPC-BCALTRSCPT00000348
F iG U R F . S . T r ar e m is s io n e le c tr o r ; r n ic ro g ra p h s a n d a c c o rrjp a .n y in g s,c?cierf area e ls c r ru n .iiif'frc .ts o rs ( S A & D ) p a t ie '- n s f o r c o s m e t ic la i c s a m p le s . T h e u i> ; pia'e ( T * ; in ( a } s h c ^ - i v / p - c a : p o ly g o n a l c is d v ig if in c d iff r a c tio n t o n ir a s l c o n to u rs fo r th e n iin c ro i epe cies. T h e a c c o m p a n y in g o A E D p a rre rn dispS ays th e characaravistJc r e c ip r o c a l a b * p la n e p r-e -u P o h ^^a g o o a i s -/m m r,ry f o r sate, T?U. a * j M b * d ir e c t io n s . in d ic a t e d o n ( A ) . M e a s u r e m e n t o f p a t t e r n io d ic ? .; es a 5 . 3 A r e p e a t lo n g a * a n d -> -?, 1 A. r e p e a l f o r b * {m e a s u re d at. (1 eCi] } . T a lc , f i b e r ( T F ) in f 53) d is p la y s ir r e g u la r e n d s a r.d n o r . r c c i iiir . e a r edges. T h e f i A u D p < m le i':t tv a is o p v :u < .k 'h e .id g O iJ .!if b u r :sy i i nsfi'C cG o-? io ic m y n ic . 'i {e .g v , r h e ( U 6 0 ) , ( C . 1 2 . 0 ; j a r e m o re - p r o n o u n c e d . T h is , n v a y b e d u e r.o b o t h o d s r u a t i c n a n d s jy u c . r jr a ; efrecr.s.. T h e o j r ' e d - s ic p'-:* la ( 0 7 ) ' in i C i d is o b e y s ar; in c ip b a n i D e.by e -S < :n e ' re r r in g p a t U r n ( t h e e f ie cls o f b o t h f o ld i n g c ;v ^r p f la ic a n d vrnaJJ a s s o c ia te d g r a in s ) . T h e a m p h i bed e fib e r ( D ) was d U fr a c ie P o n l y o n o n e o f th e p r o t r u d i n g u n f i f t h r if s - 7 he c v a x b is s h o w n , w i t h r e p e a t m e a s u r e d a-1 5 - 3 A . A re a s w h e re d ifr ra c o o n p a n ie rn i. w e re o b to 'r.e d are in d ic a te d b y lo c a tio n c irc le s ; p a rtic le s w ir e p h o to g r a p h e d a t r h e $ A 31A m a g n i f i c a t i o n x' 7 : 6 ,o 0 0 . S e rbs h t h e s a m e - n A ~ ; s c a le in D as. m a r k e d .
Micrographs obtained on a j ::OL j&cvl 17:OU with an acrekraiing voltage ?-t 70 kV. >70
CPC-BCALTRSCPT00000349
F I G U f t F 6 . T r a n s m is s io n p.fec?.? o n m ic r o g r a p h s o f a s b e s f o r rn m l :ir a is Ut eosrnm-m: r a ie , o r b a r h a n a m p h ib o le . { A c.r-d ir'} I w c >-b r y $0fi:?, f ib e r s w/.b m o r r>h o io g ic L d eh a ra c : t r i s 3ics jfsdticp.ri b y c lc r.tv o n b-c.-a.ir-. dam age.-. N o d f 'ffracr n palic.-rr v/a.s o b -ia rn e d o n e b n e r f ib e r . A r r o w m a r k e r s { A a n d 8 ; i n d c a l e a reas svolere ifr e s a b e A r n -d a m a g e d f e a t u r e s arc. m o s t pre? m in e n t - B o Lb fib e r b u n d le s a p p e a r u> Us. o n ;a.c p s c e su b stc ae-5. .m 'ie ch-'V ioLsic. f ib e r s a n d f ib r ils { C i 'vere fo s m d in a sa m p ie fo-.trsd ncgdcvf-- f<>r 5jvbc::5L 0?. b y r-ti o r d e r la c h oie; v. es. .>c3c as m a r k e d . M sf-rogr& ph.s o- b \j(ed cm 3. } b. O b j E; <Vi 7.0 U w ii.fi u n J c c e r3 iin g v o ila g e a i V7.D s.V .
CPC-BCALTRSCPT00000350
27?.
A. ftO H l. E T A L .
com parison w it h k n o w n d ilu tio n levels o f chrysotile in taic observed by e le c tro n m i c r o s c o p y , th e levels o f c o n t a m i n a t i o n o f c h ry s o tile i n the. t w o sam ples c o r r e s p o n d t o a b o u t 0 . 2 5 ~G.5% c h ry s o tile , w h ich was suggested by ' the X -ra y d iffra c tio n results. T h e c h ryso tile fibers were all shorter than 2 fim and the d ia m e te rs less th a n 0 .2 p m , e x p la in in g w hy th e y were not: visible by optical m icroscopy.
C hem istry o f C onsum er T alcum s and Pow ders
The bulk chem istry (Table 5) and mineral contents (Table 4] o f the talcum s and p o w d e rs c o m p le m e n t each o th e r in th a t one data set im plies lim its fo r th e o th e r. F o r exam ple, analysis o f sample 1 show s th e presence o f FeO and CaO {Table 5). R ecalculation o f these oxides in to values fo r the em pirical form ulas fo r tre m o lite and a n th o p h y llite indicates that s u ffic ie n t quan tities are present to acco un t fo r th e presence o f these m inerals (T ab le 4 ). A n appreciable decrease in S iO j, w hich should norm ally occur, was n o t observed, because o f the occurrence o f over 5 % q u artz c o n te n t. T h e A l2 0 3 , N a2 O , and K 3 O are reflected b y th e presence o f c h lo rite (p ro b a b ly th e p e n n in ite phase). V a ria tio n s in oxides were also o bserved in th e o th e r sam ples t h a t c o n ta in a m p h ib o ie m inerals ( 6 - 8 , 1 1 , 12, 1 5 -1 7 , and 21). in these samples, a num ber o f other factors account fo r th e w ide variation?; in o x id e percentages; in 6, th e presence o f c h lo rite
T A B L E 5 , M a jo r O x id e c o r s t e n t o f 21 C o r i s w i t e r T a l c u m ;if>d P o w d e r / *
S im p le do.
M a jo r o x id e
1
2*
3- 4
5
6
7
8
9 10 1 1
S iO , T O , A I, F e ,C , FeO
W nO M gO CaO Ha, O K,0
f.o .
.
V o a ie > J
T o ?a i
61.99 0.3 0 0.82 0.00 1 .S 1 0 .0 0
29.60 0 .4 0 0.07 0.02 0.01
.5.36
9 9 .S 8
0.00 0.00 1.30 0.00 0 .0 0 . 0.00 0 .0 0 0.00 0.00 0.00 0 .0 0 9 8 . U
io o .o o
62,6 S 0.1 4 0.3 7 0 . OS 0.3 7 0.00
29.83 0 ,0 4
0.03 0,0 2
0.03 4.66
53.72 0.04 0 - 24 0.04 3.03 0.00
2 -8.25
0 .1 0 0.03 0.02 0.03 5-38
98,20 95.88
6 3.94 0.03 0 .4.5 a 03 0.51 0.01
30.1 9 0.04
0 -0 5 0 .0 2 0.01 5 .5 i
98.79
5 2.95 0.17 3.16 0.02 0,S 6 0.00
29,02 3.46 0.00 0.05 0.13
1 0,3 2
9 8 . T9
59,67 1.40 0.87 0.18 0.84 0.00
29.23 0.90 0.05 0.05 0 . 14. 5.64
98-97
71.93 0 .1 9
15.73 0.1 0 034 0.00 2.95 2,37 0.48 1.37 0,05 5.25
100 76
S8 .6 8 0.08 0,5 8 0 .1 A 3.12 0.00
29.2 3 0.17 0.00 0.00 0.00 .5. 34
97 37
5 1 .6 5 0 .7 ? 1 ..45 0.09 0.34
0 .0 0 27.90
4.75 0.03 0.00 0.05 9.77
96.69
-59.48 0.22 2.32 1 .33 0-07 0-00
2 5 .6 7
1.61 0.4 2 0,19 o .a i 0.41
9 1 . 6 ?,
`'W e ig h ! p c r c e ri, rftc a 'c u S a c d as o x id e s , f o iio w in g s ta n d a r d pe tro n h e r n ic a i p ro c e d u re s . Til bufc a n a ly s ts o f Use p o w d e r s r e f l e c t s I h c c o m b ; r i i d r r v ^ c r a c o n L e n t * ft e . r a d d it iv e s w e re e x t r a c t e d _?5k tg w a t e r , d t io - ic H C , a c .c o n c 4 fo*cri2r p < > a n d e t h e r .
^ A n a l y s i s o f 2 : 9 8 . 7 % ~ s t a r c h o r g a n ic s and v o -a tic s ; 1 .3 % A l i Q {a iu rn in tM -n c h i o r h y d r a it ; ? ) . c S t a n d a r d taS c u s -e d as irr ta tr% ; l o r f ib e r 5t a n dare* d ilu t io n 's .
CPC-BCALTRSCPT00000351
C O N 5 U M E R T A L C LI M S A N D P O W O iiR S
27 3
sharp!y reduces the S i0 3 c o n te n t and elevates the A l 20 3 content. The presence of the carbonate m ineral calcite increases the expected CaO and v o l a t i l e c o n t e n t s ( t h e l a t t e r in c lu d e s CC)2 ); in 7, th e h ig h T t 0 2 is re fle c te d b y t h e p re s e n c e o f th e m i n e r a l r u t i l e ( T i O j ); in 1 1, t h e high- CaO,, m o d e ra te ly high A !2 0 3 j and lo w S i0 2 contents reflect the presence o f caicite. chlorite, and trem olite.
S e v e ra l o f t h e a b o v e s a m p l e s { n u m b e r s 8 , 12, a n d 1 5 ) r e q u i r e special e v a lu a tio n . S a m p le 8 is e x tre m e :-/ high in S i O j , A (, 0 3 , N a 2 0 , and Ks O and e x tre m e ly lo w in M gO con te n t. The chem istry indicates th a t this m a te ria l was n o t derived fr o m a talc ro c k , b u t ra th e r fro m one rich in a l u m i n a a n d s i li c a . T h e m i n e r a l o g y r e f le c t s th is , as d o t h e tr a c e m e t a ls (see trace m etal S ection), T h e a m p h ib o fe m inerals in sam ple 8 are a s s o c i a t e d w i t h b o t h p y r o p h y l l i t e [ A 5 i s O 22 ( O H ) 4 ] a n d q u a r t z , b o t h p re s e n t in s u b s ta n tia l q u a n titie s . T h e m ica phase is n o t p h fo g o p ite , b u t m uscovite, a ccounting fo r the presence of substantial quantities o f K 2 O and N i j O . A piagioclase fe ld s p a r was also detected in th e m in e ra l phase. S a m p le 1 2 is very h ig h in A l 2 0 3 b u t e x t r e m e ly l o w in S i 0 2 , a p p a re n tly t h e r e s u l t o f h i g h c h l o r i t e c o n t e n t as w e ll as s u b s t a n t i a l a m o u n t s o f p y r o p h y l l i t e . S a m p l e '15 is l o w irt S iO y a n d e x t r e m e l y h ig h in v o l a t i l e c o n te n t, reflecting the presence o f both carbonate phases and organic additives.
T h e trace e le m e n t analyses (T a b le 6) sh o w d is trib u tio n s th a t are in accordance w ith the k n o w n behavior o f trace elem ents in minerals. W ith
T A B ? ..IE . 5 { c o n if H L t e d ) M a *<t:' O x ir f C ra n t-c n i: rsf 71 C o n s u m e r T a lc u m
?2 1 3 14 15
S a m p le n o . 1 6 ; 7 1 $ 9 2 0 21
a"
4 7 .3 2 o . ib 9 .3 4 0 .0 5 1 ,2 2 aoo
29 .8 3 0 .6 9 0 .0 3 0 .0 5
f 0 . 2 6
99. 18
5 3 .8 3 0.1 1 3 .74 0,0 3 0 ,7 0 0 .0 0
2 7 .1 4 5..4 0 0 .0 7 0 .0 0 G.T 4
1 0 . 1
5 7 .4 7 0.11 1 .6 5 0.0 2 0 .65 0. o o
2 6 .9 3 5.5 2 0 .05 0 .0 2 0 .13
1 0..4 1
.8 3 0 ,0 7 0 .6 9 0 .0 0
. 0 .5 2 0 .0 0
2 3 .8 8 3,6 7 0 ,3 5 0 .0 7 0 ,1 0
21 ,3 4
100..0 6 9 8 .0 ? 9 5 .6 2
6 2 .2 6 0 .0 6 0,4 5 0.1 8 1 .0 4 0 .0 0
3 0 .0 0 0-1 3 0.0 3 0 .0 5 o .o ? 5 .9 2
5 4 .4 5 0 .1 0 4 .2 6 0 .0 4 1A ? 0 .0 0
3 0 .7 9 1 .1 3 0 .0 9 0 .0 2 0 .0 4 7 ,5 4
5 9 .9 3 0 .1 0 0.7 9 0 ,0 0 0.8 4 0 .0 0
3 0 .4 0 0 .5 0 0.0 9 0 .0 2 0 .1 3 5 .6 5
1 0 0 .1 9 "09-87 9 8 .4 5
5 8 .5 4 62.1 9
0.1 8
0 .0 8
! -1 1 0 . 6 9
0 .0 0 0 .0 0
1 .3 8
0.8 1
0 .0 1
0 .0 0
2 9.83 1 .1 3
30 .7 9 0.4 3
0 .0 0
0.0 7
0 .0 0
0 .0 0
0 .0 0 5 94
0,1 3 54 4
98.21 9 9 .7 3
5 6 .3 4 0.1 2 T3 5 0 .0 2 1 .3 9 0 .0 0
2 7 .9 0 1 .53 0.0 7 0 .0 0 0 ..0 7 9 .9 9
9 8 .7 3
5 734 0.21 730 0.11 . 1.0 5 0 -0 0
2 7 .4 4 1 .69 0 -1 0 0 .1 0 0 .7 0 8 .0 3
61,4-9 9.01 . 2 0 0,3 8 1 .07 0 .0 0
3 0 .5 4 0.-46 --
....
5 ,0 0
9 8 .2 0 100.1 1
^ A verag e o f 20 tafe sam pies.
"A v e ra g e c f ft t a lc anallys'fcs ir . D e e r ev aJ. f 1 9 6 2 5 .
arc- iu-st o n
{to-tai H ? 0 , C 0 2 , organ ics, arid o th e r y o ia iilc s ;-
CPC-BCALTRSCPT00000352
TABLE 6, Trace Element Content ef 1! Cofuumer Talcum and Powders
Trace
Sample no.
................................ ............... ............. ..............-- .............................................. ......................................--
......................
metals : 2 3
4
5
6
7
3
9 1 0 11 1 2 1 3 1 4 15 1 6 1 7 S3 1 9 2 0
21
3 < 1 0
<10 <10
<10 <10 <10
SO < 1 0 9 3 0 < 1 0 < 1 0 < 5 0 < 5 0 < 1 0 < 1 0 < 5 0 < 1 0 < iQ < 5 0
<10
Ce
<10 ~ <10 < !0
< 10- <10 <10
10 < 1 0 < 1 3 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0
<10
0
2 1 0 . 1 3 0 1 3 5
185 200 140 n o
115 125 115 1 2 0 4 3 0 4 3 5 4 1 0 1 6 5 HO 1 3 0 5 0 1 2 0
130
Co
35 -
< 3 85
<3 <3 <3 <3
* 8 < 3 < 3 < 3 < 3 < 3 < 3 25 < 3
4 <3
<3
<3
Cr
310 -
28 600
16 23 24 <15 2 0 25 13 24 38 43 41 3 4 0 32 3 0 2 s 25
42
Cu
<5 - <5 <5
8 < 5 < 5 9 <15 < 5 < 5 < 5 5 8 1 0 13 5 7 6 6 3
Qi
< i ...
4 <1
<1
! <1 20 <1
1 3 13 7 1 2 2
3 2 3 <1
La
<10 _ <10 <10
<10 <10 <10
40 < 1 0 < 1 0 < 1 0 < 10 < 1 0 < 10
30 <10 <10
10 < 1 0 < 10
<10
kb
7-
S 3 11
7 9 14
5 7 5 IS 7 7 5 5 9 8 9 9
7
Ni
710 -
7 172
27 13 10 < 4 2210 3 4
4 51
10 17 10 4 6 0 14 20 28
13
42
Pb
8 ...
i <5
< 5 <5 <5 49
7 <5
17
5
7 15
S6
9
7
3
r >5
Rh
5-
5 <5
< 5 <5
5 45
<5 <5 <5 <5 <5
5 5 5 <5
55
5 <5
5
235 -
130 120 2230 440 150 305
155 425
110 280 485
595 535 320
14Q 150 105
55 070
Si
10 ~ 10 ;o
10 20 3 0 160 < 1 0 25 1 0 0 ' < 5 0 15 20 20 < 1 0 15 10 10 10
5
Th
<5 - <5 <5
<5 <5 <5
6 <5 <5 < 5 <5 <5 <5 <5 <5 <5 <5 <5 <5
<5
Zri
>-
SS 3 7
12 15 20 37 > > > 35 1 ? 20 73 27 8 : : 3 >
Tr
< 1 0 -- < 1 0 < 1 0
<10
90
10 190 < 1 0
10
10
30 <10 <10 <10 <10
50 <10 < 1 0 < 1 0
<5 0
`^Values in parti per nsfffon. The Symbol < indicates the limit of detection of the analytical method. The symbol > indicates wwtniritlons of n ate greate! i.han ' ,000 ppm.
CPC-BCALTRSCPT00000353
CONSUM ER TALCUM S AMD POWDERS
'ITS
t h e c r y s t a l l a t t i c e o f a m i n e r a l a c t i n g as a s o r t i n g m e c h a n i s m f o r c a t i o n s , the cations can enter a crystal stru ctu re pro vid in g they have appropriate
size a n d c h a rg e . T h e s e p h e n o m e n a a p p l y t o m a j o r as w e ll as m i n o r e l e m e n t s . T h u s , b a r i u m is p r e s e n t in larg e a m o u n t s in s a m p le 8, w h ic h has a h i g h S<7 O c o n t e n t ( 1 . 3 7 % ) . S in c e b a r i u m a n d p o t a s s i u m h a v e s i m i l a r i o n i c r a d i i, b a r i u m is e a s ily a d m i t t e d i n t o p o t a s s i u m m i n e r a l s , s u c h as m icas and feldspars (b o th fo u n d in 8)- R u b id iu m and s tro n tiu m are also e n ric h e d in sam ple 8, since these m etals also easily s u b s titu te fo r p o t a s s i u m . G a l l i u m is f o u n d in larg e a m o u n t s in s a m p le s 8, 1.2, and 17. T h e s e sa m p le s are a lso v e ry h ig h in A ! 2. 0 3 . G a l l i u m has th e sam e i o n ic c h a r g e a n d r a d i u s as a l u m i n u m a n d , in f a c t , is f o u n d o n l y in a l u m i n u m bearing minerals.
in fo u r samples (1, 4, 9, and 16) there are sig n ific a n tly higher co n ce n tra tio n s o f c o b a lt, c h ro m iu m , and nickel than fo u n d in the o th e r samples. These fo u r samples also have high co n te n ts o f FeO (Table 5). The a ssociation o f these fo u r tra n s itio n m etals has been observed befo re in certain geochem ical e n viro n m e n ts, p a rtic u la rly in u ltra m a fic rocks. Since talcs derived fro m the m eta m o rp h ism o f serpentines and peridotites ( u l t r a m a f i c r o c k s ) are c o n s i d e r a b l y e n r i c h e d in F e O ( D e e r et. a l., 1 9 6 2 ) , i t is lik e ly th a t the d iv a le n t c a tio n s are s u b s titu t in g f o r iro n in th e b ru c ite layer o f the talc.
DISCUSSION A N D C O N C LU S IO N S
Talc, used in the U n ite d States represents a w id e range o f m in e ra lo g ica l substances, in d u stria l grade talcs are ob ta in e d fro m d iffe re n t rock types o f h ig h ly variable m ineral c o m p o s itio n w ith the result th a t the m ineral rale m a y actually be a m in o r c o n s titu e n t. H ow ever, it has been slated that co n su m e r talcum p ro d u c ts should c o n ta in at least 90% o f the m ineral o f the same name and no asbestos fiber (H ild ick-S ro ith , 1976). Review o f the l i t e r a t u r e suggests t h a t a t le a s t u n t i l 1 9 6 8 , m a t e r i a l s t h a t w e r e m a r k e t e d as cosm etic ta lcu m p ro d u c ts did n o t necessarily c o n fo rm to these criteria.
Talc m ineral m ay o ccu r in a p la ty fo rm o r in a fibrous fo rm . Talc f i b e r m a y o c c u r as a s m a ll p r o p o r t i o n o f th e m i n e r a l d e s p o s it o r as a m a jo r c o n s titu e n t. In te rg ro w th s o f talc w ith o th e r m ineral phases are c o m m o n . These phases may be sim p ly m acroscopic zones a djoining laic m in e ra l o r m ay o c c u r as m ic ro s c o p ic irit.ergrow ths w ith in the talc. O f the m a n y m in e ra ls t h a t m a y c o e x is t w it h talc., a n u m b e r o f a s b e s tifo rm phases c o m m o n ly occur: tre m o lite , a n th o p h y llite , and ebrysotile have been id e n tifie d in these d e p o s its . In a d d i t i o n , free silica (q u a r tz ) is a f r e q u e n t c o n s titu e n t. T h e trace m etal c o n te n t m ay in c lu d e elevated levels o f n icke l, chrom ium , and cobalt.
T h e r e is g e n e ra l a g r e e m e n t b e t w e e n th e m i n e r a l c o m p o s i t i o n a n d the. m a jo r and trace elem ent c o n te n t o f the consum er talcum products. O n the
CPC-BCALTRSCPT00000354
7 fy A . N . R O 'H L E T A L .
basis, o f m i n e r a l a n d c h e m i c a l c o n t e n t s , t h e t y p e o f g e o lo g ic a l p ro v e n a n c e m a y be. a s c e r t a in e d .
M etho d olo gy has been developed f o r q u a n tita tiv e X -ra y d iffr a c tio n d e te r m in a tio n o f a n tb o p h y liite , tre m o lite , serpentine, -and q u a rtz in c o n su m e r talcum s and pow ders, i im portant fa cto rs in the c a lib ra tio n standard developm ent include selection o f talc and reference m inerals and the selection o f diagnostic X -ray reflections. The sam ple preparation technique is sensitive a n d re p ro d u c ib le . D ilu tio n standards- -a-re step scanned over diagnostic reflectio n areas, peak areas are m easured, and a set o f standard c a lib ra tio n curves is d e v e lo p e d by regression analysis. S am p les o f c o nsu m er talcum s and pow ders are prepared and an a lyzed under identical conditions and com pared w ith th e c a lib ra tio n curves, p e rm ittin g q u a n tita tiv e analysis o f these m inerals. X -ra y d iffr a c tio n alone c a n n o t distin g uish betw een asbestiform and fragm ented form s o f a n th o p h yllite and trem o lite nor betw een asbestiform and p laty serpentine varieties, {electron m icroscopic analysis was used to distinguish betw een these fo rm s.
Mirteralogical characterization o f 21 consum er talcum s and powders sh o w e d th a t 1 0 c o n ta in e d m easurable c o n c e n tra tio n s o f asbestiform trem olire and a n ih o p h y ltite , and some-aiso contained fragm ented form s o f these m in e ra ls . T w o samples contained trace q uantities o f chrysotile (G .25--Q,5%), T h e s e o b s e r v a t io n s w e re c o n f i r m e d b y t r a n s m i s s io n e l e c t r o n m icro sco p y. T h e am phiboie phases present in these talcum products ranged in a m o u n ts fro m several tenths o f a percent to over 14% by w e ig h t. Q u a rtz was p re s e n t tri e ig h t c o n s u m e r talcs In a m o u n ts ranging from 1.6 to 3.5.1% by w eight.
C onsum er talcum products are fo r the m ost p a rt co m p le x mineral assemblages, w h ic h c o n fe r X -ra y s o rb in g and flu o re s c in g e ffe c ts th a t are n o t eq u ivale n t to , and are usually greater than, those o f the b in a ry system s used in p rep arin g the d ilu tio n standards. In consum er talcum pro ducts m inerals such as talc, micas, c h lo rite , calcite, d o lo m ite , and others tend to d im in ish reflectio n intensities o f asbestiform m in e ra ls by sorbing X -ra y s o r b y c o n t r i b u t i n g to b a c k g r o u n d noise. A ls o , re peat ru n s on some, selected specim ens have dem onstrated! greater peak areas due to slight m o d i f i c a t i o n s i n i n s t r u m e n t a l s e t t in g s (e.g., in cre a s e irj receivin g s l i t w id th ). Therefore, the values to r w eight percent co n ce n tra tio n s given in this report are conservative.
E x a m in a tio n o f the same c o n s u m e r ta lc u m p ro d u c ts by b o th o p tic a l and transm ission e le c tro n m ic ro s c o p y in d ica tes th a t n o t all o f th e m a te r ials fall w ithin the d e fin itio n o f fib er o r asbestiform . For e xa m p le , one c o n s u m e r ta lc u m p ro d u c t th a t c o n ta in e d ' m o re th an 7% tr e m o lite was observed to co ntain both fragm ented tre m o lite grains by optical m icro scopy and asbestiform fiber w ith 3:1 or-greater ieng th -to -w id th ratio by transm ission electro n m icroscopy. O p tical m icroscopy m ay provide useful in fo r m a tio n . H o w e v e r, m ore c o m p le te c h a ra c te riz a tio n can be o b ta in e d by e le c tro n m icroscopy and selected area e le c tro n d i f f r a c t i o n . Using electron
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m ic ro s c o p y , fo r e x a m p le , several -sam ples o f co n s u m e r ta lc u m p ro d u cts e x h ib ite d both free am p h ib o ie fiber, discrete fro m talc grains, and, in a d d itio n , num erous small am phiboie fib e rs were visible, apparently inter la ye re d b e tw e e n talc or c h lo r ite plates (see Fig. 6A ) ;
P relim inary e x a m in a tio n o f the asbestiform a m p h ib o ie s-b y an electron m ic r o p r o b e te c h n iq u e has d e m o n s tr a te d t h a t in d iv id u a l f i b e r c h e m is tr y is identical to those fibers encountered in the IA R C Asbestos Standards (T im breli and RendaO, 1971).
O n the basis o f the m ineralogical and chem ical characterization o f these product's, all fo rm u la te d p rio r to June 1973, we c o n c lu d e that co s m e tic grade talc was n o t used e xc lu s iv e ly . T h e presence in these
products o f asbestiform a n th o p h yllite and trem olite, chrysotiie, and quartz indicates the need fo r a regulatory standard fo r cosm etic talc. This standard sh o u ld be co g n izan t o f talc c o m p le xitie s, m ineralogical and chem ical in nature, and should provide fo r adequate analytical protocols to ensure m o n ito rin g . We also re co m m e n d that evaluation be made to
d e te rm in e possible health hazards associated w ith th e use o f these products.
A PP E N D IX A : D E F IN IT IO N S O F TER M S USED IN T E X T
Asbestos " A name applied to a group o f naturally fibrous m inerals" (chrysotiie, am osite, crocidolite, trem olite, a n th o p h yllite cited by nam e) (Bureau o f M ines, 1968). T h e term asbestos has also been applied to co m m ercially exploited fib ro u s clays, including attapuigite and palygorskite (W hittaker, 1968). Asbestos im p lie s cu rre n t or possible e x p lo ita tio n , based on the presence o f special physical and chem ical properties, determ ined on the bulk sam ple level. F or exam ple, high fiber tensile strength, fle x ib ility , lo w heat c o n d u c tiv ity , high electrical resistance, and chem ical inertness are properties o f asbestos. N o n co m m e rcia l varieties o f the same m in e ra l m a y n o t possess th e same q u a litie s o n the b u lk level. F o r exam ple, am osite has been considered to be the e co n o m ica lly exploited variety o f gruente (Deer et ai., 1962). I f so, and even this is c o n te s te d a m o n g m in e ra lo g ists to d a y , large m a crocrystals are s ig n ifi c a n tly d if f e r e n t p h y s ic a lly a n d s t r u c t u r a l l y . G r u n e r ite f ib e r is rig id , am osite fib e r is fle x ib le ; g ru n e rite y ie ld s w e ll-d e fin e d single X -ray reflections w ith n o n re la tio n a l film techniques, amosite y ie ld s 'm uitiple r e f le c t io n s as i f r o t a t e d in th e X - r a y b e a m ; g r u n e r it e a p p e a rs t o be a single c ry s ta l, a m o s ite splays as i f c o m p o s e d o f stra n d s. H o w e v e r, w h e n b o th substances are pulverized, the re su lta n t po w d er yields sub m icro sco p ic fib e rs, m a n y o f w h ic h are v ir t u a lly in d is tin g u is h a b le o n the basis o f m o rp h o lo g y , s tru c tu re (d e te rm in e d by selected area e le ctro n d iffra c tio n ), and ch e m istry (d e te rm in e d b y an e le ctro n probe
CPC-BCALTRSCPT00000356
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X . N. SOHL A L .
t e c h n i q u e ) . A m o s ite m a y be c o n s i d e r e d as an a g g re g a te o f u n o r i e n t e d , d is c re te , g ru n e ritc cry s tals w ith Only t h e c a xis 'in c o m m o n a lig n m e n t.
C om m inution o f such aggregates produces fibers w ith character istics identical to those o f single crystals o f g ru n e r itc th at have been s im ila rly p u lv e riz e d . S om e w o rk e rs have suggested th a t m echanical size reduction o f am osite yields fibers w ith crystal g ro w th surfaces rather th a n cleavage surfaces. .Since am p.hibole cleavage tends to parallel p ro m in en t crystal face planes, such d is tin c tio n s on the subm tcroscopic level m a y disappear. - T h i s appears to be the case fo r tre m o llte and a n t h o p h y i ii t e as w e ll. H o w e v e r, because no m e t h o d s e x is t t o d is tln . guish betw een possible differences in fib e r su rfa ce , w e d o n o t re fe r t o a n t h o p h y i ii t e and t r e m o l lt e fib e rs in these ta lc u m s as asbestos. Instead t h e y are r e f e r r e d t o as a s b e s tifo rm . I t s h o u l d be s tre s s e d , h o w e v e r , t h a t evidence does n o t exist th a t w o u ld indicate that fibers w ith crystal g ro w th surfaces o r cleavage surfaces possess lesser o r greater biological p o te n tia l th a n fibers f r o m c o m m e r c ia l asbestos -deposits. A sb e stifo rm " Form ed like o r resem bling asbestos; fib ro u s ; . . . . (Bureau o f M in e s , 1 9 6 8 ) . T h e t e r m is u se d h e r e i n For a m p h ib o J e s ( a n t h o p h y i i i t e and trem o lite) seen on both lig ht and sufomicroscopie e x a m in a tio n , w h ic h resem ble c o m m in u t e d asbestos varieties, o n the. basis o f m o r p h o lo g y . E s s e n tia lly , w h e n these fib e rs are derived front com m er cial deposits we te rm th e m " asbestos'5 and w hen analytically identical f i b e r s are f o u n d as n o n c o m m e r c i a l i n t r u s i o n s w i t h t h e m i n e r a l ta lc , w e
term them ' `a s b e s lrfo rm ." T he use o f tw o term s does n o t im p ly differences th a t can be a n a ly tic a lly d e te rm in e d . F ib e r " T h e smallest single s tra n d o f asbestos o r o th e r fibrous m aterials" (Bureau o f M ines, 1 9 6 8 ). We use th is te rm in a b roader sense. For exam ple, chrysottie fibers are called fib rils , possessing u n it diam eters o f a b o u t 2 0 0 - 4 0 0 A . C o h e re n t bundles o f fib rils are also called fibers. Fiber in the present te x t is used to denote any elongated single mineral u n it visible on the lig h t o r electron m icroscopic level. The O ccupational S a fe ty - and H ealth A d m in is tra tio n has applied a 3 :1 lengih-to-w idth ratio to distinguish fiber from mineral fragment.
APPEN D IX B: C R Y S T A L C H E M IS TR Y , C R Y S TA L STRUCTURE, AM D G EO LO G IC AL OCCURRENCE OF TALC
C hem istry o f Talc
/.
T h e e m p i r i c a l c h e m i c a l f o r m u l a o f t a l c is M.g3 5 L ( O (o (OH)-,. , b u t ferrous and fe rric oxides, alum ina, titarsia, soda, lim e, and oxide:; o f manganese have been re p o rte d in q u a n titie s up to several percents b y
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w eight. T ita n iu m and alu m in u m appear to substitute fo r silicon, whereas iro n , n ic k e l, and manganese su b stitu te fo r m agnesium . A lk a li metals are n o t re a d ily a c c o m m o d a te d in th e s tru c tu re and e v id e n tly o ccu r as in te r la y e r io n s or as c o m p o n e n ts o f m in e ra l im p u r itie s / F o r e x a m p le , excess
calcium m ay reflect th e presence o f the interlayer, m ineral phase trem olite (D e e r e t ah, 1 9 6 2 ; S tem p ie and B rin d le y , I9 6 0 ) .. O n e m a jo r talc deposit in th e eastern U n ite d S ta te s c o n ta in s su b s ta n tia l a m o u n ts o f n ic k e l, as m u ch as 0 .2 % . N o tw ith s ta n d in g th ese m in o r c o m p o n e n ts , ta lc is e s s e n tia lly {b y w eight) 32% M gO , 63% S i0 2 , and 5% structurally bound w ater.
T a lc S tru ctu re and C rystal Habit:
^ T h e three-layered crystal structure com prises a sheet o f octahedrally co ordin ated M g (O H ), groups (th e brucite layer) sandwiched betw een tw o planes o f te tra h e d ra lly lin k e d $ i 0 4 groups (silica layers). A p ic a l oxygens o f th e silica sheets are d ire c te d tow ard the b ru c ite 'la y e r and in part re placed by h y d ro x y l groups, w hich fo rm a p o rtio n o f the inner structural
u n it. V a le n c e b a la n c e is a c c o m p lis h e d w ith in th e s tr u c tu r e , so t h a t th e re is 3 net zero charge on juxtaposed u n it layers at the silica base interfaces.
T h e basic u n it o f th e ta lc s tru c tu re was d e te rm in e d o ver 4 0 yr ago {G ru n e r, 1 9 3 4 , H end ricks, 1 9 3 8 ), y e t the repeated cell geom etry and space g ro u p -were o n ly r e c e n tly re s o lv e d . X -r a y single c ry s ta l p a tte rn s n o w in d ic a te ta lc to be tr ic fm ic ( R a y n e r an d B ro w n , 1 9 6 6 ; Ross e t a!.., 1 9 6 8 ) .
In addition to chem ical and structural com plexities, talc occurs w ith both plate and fiber habits (F o rd , 1 9 5 7 ). The developm ent o f the fibrous cyrstai fo rm , w ith an e lo n g ated c ry s ta llo g ra p h ic t?-axis, m ay be a m a n i fe s ta tio n o f Io n ic s u b s titu tio n sin ce its re fra c tiv e in d e x is h ig h e r th a n p ia ty talc (Fleischer and O sb o rn , 1 9 5 7 ; G ru n e r, 1 9 4 4 ). Talc th a t contains s u b s ta n tia l a m o u n ts o f these e lo n g a te d fo rm s is re fe rre d to in th e m in e ra lo g ie s ! lite ra tu r e as fib r o u s ta lc . S im ila r o b s e rv a tio n s w ith regard to th e m in e ra l b ru c ite have been re p o rte d (L ie b iin g . and L an g er, 1 9 7 2 ) in w h ic h high iro n c o n te n t in th e n o r m a lly p ia ty b ru c ite is associated w ith th e d e v e lo p m e n t o f a fib r o u s h a b it, i t is o f in te re s t to n o te th a t m inn eso taite, considered by sam e to be an iron-rich fo rm o f talc, always occurs w ith a fibrous, o r even a needle-like, habit (G runer, 1944).
F o rm a tio n o f T alc in th e L a b o ra to ry o f N atu re
in closely c o n tro lle d e x p e rim e n ta l systems, talc has been synthesized (B ow en and T u ttle , 1 9 4 9 ; Y o d er, 1 9 5 2 ). B ulk chem istry, w ater fugacity, tem p eratu re, and pressure param eters are d efin ed w ith in extrem ely restrict ed lim its and ranges to produce relatively pure crystallization products. H o w e v e r, in la b o ra to ry s y n th e s is , ju s t as in n a tu re , c o e x is tin g m in e ra l phases are p ro d u ced i f slight variatio n s in an y o f the param eters are in tro d u ced . These phases in clu d e a n th o p h y ln te , serpentine, and in some instances tre m o lite .
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A . N. R O H L ET A L
N ature o f Talc Plates
Electron m icroscopic exam ination o f talc minerals demonstrates that single talc grains consist o f contiguous single crystals, mosaics o f dis oriented crystallites, and intergrowths- w ith other mineral phases, pa rticu larly tre m o H te (K ie in fe ld et a!., 1973; S te m p le and B rin d le y , I 9 6 0 : W right, I9 6 0 ). Selected area electron d iffra c tio n patterns obtained on these objects display, in o rd e r, single crystal arrays, D ebye-Scherrer rings, and superimposed com plex patterns characteristic o f intergrow n single crystal phases.
Talc and M ineral Intergrow ths
T re m o iite is one c o m m o n in te rg ro w th in talc, and it requires relatively little energy th e rm odynam ically to occur. Replacement of magnesium by c a l c i u m in th e b r u c i t e l a y e r m a y lead t o s t r u c t u r a l as w e l l as c h e m ic a l m o d ifica tio n (Bragg and C faringbufl, 1965). R o ta tio n o f u n it tetrahedra in talc fo rm s do u b le chains fro m sheets, readily accom plished by su b stitu tio n o f M g(O H )-, by C a ( O H ) j . T h e b u lk c h e m is tr y is th e re b y changed fr o m M g 6 5 i s 0 3c }( O H )< | t o C a 2 M g s S i a O J2 ( O H ) j . T h e f i n a l s t r u c t u r a l a rr a y is re m a rk a b ly s im ila r in b o t h m a te ria ls ; the c ry s ta llo g ra p h ic -axis o f talc is approxim ately 5.26 A , w hich corresponds w ith the c-crystallographic axis o f tr e m o H te ( a p p r o x i m a t e l y 5 . 2 4 A ) ; th e -axis f o r ta lc is a p p r o x i m a t e l y 9 .1 0 A , w h ic h is equal to the b f2-axis o f tr e m o iit e ; th e c-axis o f talc, a p p r o x im a te ly 18.8 A , is a b o u t e q u a l to tw ic e th e fir-dimension o f tre m o iite (a p p ro xim a te ly 18.2 A ). T h e monocisntc stacking angles, the beta-angle, are w ith in a fe w degrees o f each other.
In te rg ro w th s m a y f o r m in w h ic h a m p h ib o ie fo r m a tio n is n o t c o m p le te s o t h a t a m i x e d phase e x is ts , r e f e r r e d t o m i n e r a l o g i c a i l y as " t a l c b o l e s . " T h e s e a re not. as ra re as o n c e b e lie v e d a n d m a y even be c o m m o n in th e more com plex talc deposits.
APP E N D IX C; IN D U S T R IA L A N D COSM ETIC GRADE TALCS
Studies have dem onstrated th a t industrial talc o fte n consists o f a v a rie ty o f m in e ra ls , th e u ti l iz a t io n o f w h ic h is based o n ph ysica l p ro p e rtie s rather than mineral com position (Hogue and M allette, 1949; Schulz and W illiam s, 1 9 4 2 ; T h o m p s o n , 1 9 7 4 ; Wells, 1965).
Early analyses o f cosm etic talc also showed a w ide range in mineral com position. O f six such products exam ined in one study, o n ly 6-47% by w e ig h t o f th e in o rg a n ic m ateria! th a t c o n s titu te d the p ro d u c t was the m ineral talc; 14-51% , serpentine minerals; 5-77% carbonate minerals; 0-trace, q u a rtz; 0-tra ce , tre m o iite ; 3 -1 2 % , o th e r minerals (S chulz and Williams, 1942).
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A P P E N D IX D: B IO L O G IC A L H A Z A R D S A S S O C IA T E D W ITH T A L C EXPOSURE
A isne, diffuse, bilateral, progressive fib ro sis was observed am ong
m in e rs and m illers o f tre m o lite ta lc 'in G e o rg ia (D reessen, 1 9 3 3 ; Dreessen
and D a lla V a lle , 1 9 3 5 ) . Siegal et al. ( 1 9 4 3 ) s tu d ie d a p o p u la t io n o f
w o rk e rs m in in g and m illin g trem o lite and a n tb o p h y lli to-bearing talc
deposits in N e w Y o r k state. In a d d itio n to the bilateral fibrosis, pleural
p laq u es, s im ila r to those e n c o u n te re d in asbestos w o rk e rs , w ere observed.
R e v ie w o f p o s t m o r t e m m a te ria l in this s t u d y in d icated th a t asbestos
bodies w ere present in lung tissue. These fin d in g s w ere also rep o rted in
cases o f severe p n e u m o c o n io s is in tr e m o lit e m illers b y D a y m e n (1 9 4 6 ) ,
and by Porro and Levine (1 9 4 6 ).
M lllm a n (1 9 4 7 ) rep o rted th a t exp osu re to 'cosm etic-grade talc p ro
duced nodular fibrosis in w o rk e rs . N o q u a rtz was detected in the dust.
T h e a u th o r concluded th a t talc its e lf was capable o f p roducing scarring.
The o b s e rv a tio n was s u p p o rte d in studies b y Retch man (1 9 4 4 ) and by
W yers (1 9 4 9 ) and in a s tu d y o f talc m in e rs and m illers in Ita ly where
exp osu re t o p u re talc p ro d u c e d a 10 % in cid en ce o f p neu m o co n io sis in
w orkers (Parm eggiani, 1 9 4 8 ). Excess deaths a ttrib u te d to pneum oconiosis
have been reported a m ong w orkers in n o rth e rn Ita ly m in in g talc co n
s id e re d to be free o f a s b e s tifo rm fib e rs (R u b in o e t al,,, I 9 7 6 ) .
S o m e in v e s tig a to rs h ave h e ld th a t fib ro u s ta lc s ( n o t d iffe r e n tia te d as
talc, o r asbestos f ib e r ) are b io lo g ic a lly m o re h a z a rd o u s th a n p ja ty talcs.
F o r e x a m p le , in a re v ie w o f this lite r a tu r e b y P o rro et al. (1 9 4 2 ),
G io y n e a n d G a rd n e r are referred to as co n s id e rin g th a t the clin ica l,
ra d io lo g ic a l, and p a th o lo g ic a l disease states o f asbestosls and talcosis are
very sim ila r. T here are several repo rts o f th e occurrence o f asbestos bodies
In th e k in g tissue o f w o rk e rs exposed to talc (D a y m e n , 1 9 4 6 ; H obbs,
1 9 5 0 ; K iein feld et al., 1 9 7 3 ; M cL au gh lin et ai., 1 9 4 9 ; Porro et al., 1942).
S e v e ra l studies suggest t h a t f i b r o u s ta lc s are m o re d an g ero u s as a resu lt
o f the included asbestos fib e r. F o r e xam p le, M c L a u g h lin et al. (1 9 4 9 )
c o m p a re d fib e rs in talc w ith the p ro p o r tio n o f fib e rs recovered fro m the
lu n g tissue o f an exposed w orker.. A larger c o n c e n tra tio n o f fib e rs was
f o u n d tn t h e tissues as c o m p a r e d w i t h t h e r a w t a l c . T a l c 'p n e u m o c o n i o s i s
was r e a f f ir m e d b y K ie i n f e l d a n d M essite ( I 9 6 0 ) in t h e i r s t u d y o f th e N e w
Y o rk stale talc w orkers.
.
in a s t u d y by' K i e i n f e l d e t a i . ( 1 9 6 7 ) i t was d e m o n s tra te d t h a t ta lc
pneum oconiosis accounted fo r alm o st 30% o f excess deaths am ong the talc
m iners and m illers. M ost o f these were due to th e co m p licatio n o f
p n e u m o c o n io s is , c o r p u lm o n a le . H o w e v e r , 2 1 % o f th e 91 d e a th s re c o rd e d
were due to m alignant tu m o rs: lung carcinom a, pleural fibrosarcom a, and
sto m ach , co lo n , rectu m , and p ancreatic cancers. A p eriton eal 'meso
theliom a was reported as w e ll, in a d d itio n to these tu m o rs , re tro p e rito n e a l
sarcom a, h e p ato m a, and le u k e m ia w ere also fo u n d . S tatistical evaluation o f
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A.. N . R O H E E T A L .
these data indicated th a t a 3- to 4-fold excess o f cancers existed in this g ro u p , as c o m p a r e d t o a m a tc h e d c o n t r o l p o p u l a t i o n .
T h e biologica! a c tiv ity of, b o th tre m o iits and a rth o p h y flite fibers has been kn ow n f o r som e tim e , an d b o th have been c ite d as asbestos m inerals by Mere w et her (1 9 3 0 ) and N oro ('1946). Asbestos disease am o n g w orkers (and o th e rs exposed to a n th o p h y llite and tre m o lite ) has been reported ( B u iiik o v and Badajov, 1 9 7 0 ; k iv ilu o to , 19 6 0 ; M eurm an, 1 9 6 8 ; Meurm an et a h , 1 9 7 4 ; S c h e p e rs , 1 9 '6 5 ; W egefius, 1 9 4 7 ; Weiss an d B o e ttn e r, 1 9 6 7 ).
Recent exp erim en tal d ata also in d icate th a t Ire m o lite fibers are biologically active (G raham and G raham , 1 9 6 7 ). Som e investigators have suggested th a t in o rg a n ic fib e r fib r o g e n lc ity an d c a rc in o g e n ic ity is lim ite d o n ly b y its a b ility to reach th e alveolar space (H o lt et aL, 1 9 6 5 ; Pott and Friedrichs, 1 9 7 2 ; P o tt et aL, 1 9 7 4 ; R obock and K lo sterko tter, 1976; Stanton and Wrench, 1 97 2 ).
W agner et at. (1 9 7 5 ) rep o rte d lung scarring in W istar rats w ith pure talc, exposed by in h a la tio n . The severity and e x te n t o f th e lung scarring was co m p a ra ble to th a t p ro d u ce d b y chrysotile asbestos under identical e xp e rim e n ta l condition?;, in a d d itio n to lung scatring, ingestion o f talc was
re p o rte d to be associated w ith le io m y o s a rc o m a o f th e sto m ach as w elt as one adenom a and several sarcomas o f the uterus. H owever, the exposure levels were high and the n u m b e rs o f observed tu m o rs sm all, so th a t statistical v a lid a tio n o f the carcinogenic p o te n tia l o f pure ta lc and its relevance to hum an exposures were n o t achieved.
T h e re are also exten sive d a ta co n cernin g hazards associated w ith exposure to silica o r trace m etals, p a rtic u la rly nicke l and chrom ium (N a tio n a l Research C o u n cil, 1 9 7 5 ). A n a ly tic a l data are presented here that suggest possible disease p o te n tia l and th e need fo r investigation in these areas.
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' MEMORANDUM o f m e e t i n g
March 22, 1976
at
Environmental Sciences Laboratory Mount Sinai School of Medicine City University of New York
BETWEEN: Members of the Staff of Environmental Sciences Laboratories
Arthur M. Langer Arthur N. Rohl
Division of Cosmetics Technology, FDA
Clifton H. Wilson Ronald L. Yates
SUBJECT: Analytical Methodology for the Detection and Determination of Asbestos Minerals in Talc
Upon arriving at the laboratory, Dr. Wilson and Mr. Yates were greeted by Dr. Rohl. He stated that Dr. Langer would be present as soon as possible. Mr* Yates gave- Dr. Rohl the cosmetic talc samples that Dr. Langer had agreed to analyze. In turn we requested and received subsamples of the 10 cosmetic talcs in which Dr. Langer reported the presence of tremolite and/or anthophyllite. These are:
1 . Body powder, Cashmere-Bouquet 2 . Rosemary talc 3. Brut for Men, Faberge 4. Air Spun 'Face Powder, Coty 5. Baby talc, Bauer and Black 6 . Black Label, Yardley 7. After Shave talc, English Leather 8 . ZBT Baby Powder 9. Invisible talc, Yardley 1 0 . Shave talc, Mennen
Dr. Langer arrived approximately 30 minutes after our arrival. Mr. Yates presented him with the covering letter concerning the cosmetic talc samples DOST had provided for his analysis.
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,2 -
Dr* Langer, Dr. RGhl, Dr. Wilson and Mr. Yates then discussed the following topics:
Sample Preparation and Instrumental Conditions for Analysis of Talc by x-ray Diffraction* - Dr. Langer stated that he did not believe it possible to prepare a sample for x-ray analysis that had a completely random orientation of the chrystal lattice. He did not think that random distribution was important if sample preparation techniques were consistent. Mr. Yates informed Dr. Langer that in the proposed CTFA method, preferred orientation was inevitable because the sample was pressed hydraulically. Dr* Langer thought the technique acceptable if consistent results were obtained. Dr. Langer demonstrated the sample preparation technique used by his group. After preparation was completed, sample was step-scanned in increments of 0.02 through the area ^of interest until a count of 2000 was obtained at each step. Divergence slits of 4 are frequently, although not always, used. When. Dr. Wilson asked Dr* Langer about the possibility of scatter and high background from the use of a 4 slit, Dr. Langer stated that the use of a smaller slit would probably increase resolution and sensitivity.- He was somewhat noncommittal about the. effect of a 4 slit oh quantitative results* Dr. Langer summed up by stating that if good standards are used and sample preparation is reproducible and consistent, reliable analytical results should be obtained. He said that all of the 10 samples.found to contain tremolite and anthophyllite by x~ray dif fractometry were examined by transmission electron microscopy using selected area.diffraction to verify x-ray results. Dr. Langer was somewhat disgusted by the talc industry's attitude. He said the results of his work has been known to the industry for several years but nothing was done until the analytical results became public.
Tremolite. - Dr. Langer stated that tremolite and talc fibers can be easily differentiated using light microscopy. The cleavage of tremolite and anthophyllite is 90 to the crystal axis while talc has an angular cleavage. There is also a difference in refractive index. Tremolite and anthophyllite can be differentiated by the difference in aspect ratio. Dr. Langer demonstrated by preparing a slide of Cashmere Bouquet talc. Under the microscope tremolite was observed as short particles with 90 cleavage. Anthophyllite had the same cleavage but was definitely fibrous, having aspect ratios typically 30 or 40 to 1* Talc fibers appeared to have a cleavage of approximately 60. Dr. Wilson asked Dr. Langer to examine a sample of tremolite he had brought along* Dr. Wilson said that he had been using the sample as a standard but that x-ray analysis indicated impurities. Dr. Langer examined the sample using
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optical microscopy. He stated it contined anthophyllite, tremolite, quartz and talc. X-ray analysis of the sample indicated talc, anthophyllite and tremolite. He had a microscopist on his staff examine the sample using optical microscopy* His analysis confirmed Dr* DangerTs results. Dr. Langer stated that our tremolite standard was very impure and probably originated from New York, He gave Dr. Wilson the address of the Cape Asbestos Co. in London, a firm that could provide samples of Korean tremolite, considered to be the purest available.
Dr. Langer said detectability levels for tremolite was approxi mately 0.1% by x-ray diffractometry. If tremolite particles had aspect ratios of 3 to 1 or greater they were considered fibrous.
Chrysotile, - According to Dr. Rohl, detectability by x-ray fluorescence was 0.25% depending on size and crystallinity. Dr. Rohl had some photographs taken of chrysotile fibers (fibrils) using transmission electron microscopy (TEK), Photograph showed fibers containing several fibrils and individual fibrils. Aspect ratios were extremely high. When examining talcs by TEM a count of 3-5/grid square is considered background. In two of the 19 commercial cosmetic talcs examined, fiber counts of approximately 24 fibrils/grid square were obtained. Dr. Langer considered this to be quite low and probably not hazardous. In general he did not think that chrysotile was a real problem as far as cosmetic talcs were concerned. He refuted claims made by some that asbestos fibers were not present in the environment due to use of asbestos brake shoes in automobiles. He stated that they have analyzed dust obtained from auto brake drums and have identified asbestos fibers.
Nickel. - In reference to the high amounts of nickel present in some talcs, Dr. Langer said that nickel replaces magnesium In the talc lattice and becomes a nickel hydroxy silicate complex. He Is not convinced that nickel Is harmless in this form because of its similarity to nickel hydroxide, which has been found to cause rhabdomyosarcomas in rats when injected.
Transmission Electron Microscopy (TEM) . - Dr* Rohl demonstrated the use of TEM for the analysis of talcs using previously prepared samples. Using a prepared sample of unknown identity, he pointed out structures typical of talc and tremolite. He also demonstrated that use of selected area diffraction. The crystal to be examined Is centered on the screen and the beam Is then passed through the area of the crystal desired. The diffraction pattern is displayed on the screen as a series of dots quite similar to a Laue photograph. The pattern can then be compared with those of standards for characterization.
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In general, the Environmental Sciences Laboratory is well equipped for mineralogical analysis having two transmission electron microscopes, two scanning electron microscopes, an x-ray diffractometer, an optical microscope and a differential thermal analyzer
/
Ronald L. Yates
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