Document JNopNpEnapLv1e9QyX5y7BNpa

FILE NAME: Talc (TALC) DATE: 1976 DOC#: TALC017 DOCUMENT DESCRIPTION: Journal Article - Consumer Talcums and Powders Mineral and Chemical Characterization \ I y t f t TM F r *L CONSUM ER TALCUM S AND POWDERS M IN ERA L AND C H EM IC AL C H ARAC TERIZA TIO N A. N. Rohl, A. M. Langer, I. j. Selikoff, A. Tordini, R. Klimentidis Environmental Sciences Laboratorv Mount S.nai Schooi or Medicine of the Qtv Universuv of New York New York, New York D R. Bowes, D. L. Skinner Department of Geology, The Umversitv of Glasgow, Glasgow, Scotland Representative zonsumer talcums and pow ders. including 20 oodv powders, buoy o o w a c s , facia! talcums, an c also one pnarm aceut/cai talc, were analyzed to determ ine tn e ir m m eraiogicai and chem ical com position Where Rnow n. all w ere form ulated p rio r to 19~3. Q r me 20 p rocuczs JO co n tain e d a e te ctab ie am o un ts o f m ernonte an d a n ih o p n v iin e , p rin c ip a lly aso e stifo rm . wnn'e some also co n ta in e d frag m en ted fo rm s or tnese m inerals. The am ounts ranged from tenths o f a percent to o ver ]**% o v weight, tw o contained detectaole am ounts o f enrysouie asbestos fiber Eight contained auartz. seven ranging tro m 2 to 5 % , with one as nign as 3 5 % . The analyses sn o w e a th a t the co n su m er p ro a u cts exam m ea were rarely the pure m ineral talc, out rattier were m ixtures o f various m inerals; ,, ome samples consisted o f three to five m inerals, o n lv o n e o f w m ch was true O th e r co m m o n m ineral phases m c.u d e d ch lo rite . p!at\ serp entine, oyroo nyiU te, mica, and carbonate minerals. Kaolin auditive was id en tified m 'w o products. The single pnarm aceuncai talc exam ined contained o n iv a trace am ount sf auartz The _ /?' micai co m p ositio n o: these products, m cluding both motor o'nde ana trace :eme.ni content, correlated with their m ineral com ponents. F o u r samples co n tain ed .u o s ijn iia l con centrations o f niche:, cooait. and enrom ium . suggesting latu ce suosutu- on ;he p resence ot trace m m e ra/ onases G e o io a ica l p ro ve n an ce 01 the tales ma\ o* a- K ?ria m e a on :ne oasis o f cnemistr-' Possible adverse health effe cts fro m r\ e-im ttent use o t these p 'o a u c t s , especially those that co n tain aso estifo rm and 'r s o r 'e n te a a n th o o n v ifte an a trem oute. cn r ''soule, auartz. end trace metals, are INTRO D UCTIO N C c n s u r 'e r taRam s and n c w a e rs are considered bv the general oubiic re taiC, an moresSiOn that :S conveyed ana strengthened bv the orodact `.R.t'01^' :nc^; u;_ " 256 A N. ROHL 5"" Al names and ingredients listed on the container labels. However, knowledge 0 the geological occurrence and mineralogica! character of source materials suggests the nature of talc to be highly variable and complex 1wenty-one consumer talcums and powders (Table 1) were mineraioeicallv and chemically analyzed to determine whether these products are actually talc mineral. - Talc is a defined mineral entity, based on specific chemical, crystalline and physical properties (Ford, 1957). The empirical chemical formula,' V k 2' 15 seldom observed in nature as a result of cation substitution. For example, magnesium is frequently replaced by iron nickel, chromium, or manganese in the crystal structure. Talc is a sheet silicate, with a structural unit consisting of three lavers; a sheet of octahedrally coordinated magnesium hydroxide grouos is sandwiched between two layers of tetrahedraily linked silica layers. The Van der Waals bond between the talc sheets are of low energy accounting for the ease with which talc as well as other sheet silicate minerals (micas, clays) cleave T A B L E 1. Designation of Contents in Brand Name or Labe! Sample no. Date of formulation Products 3 8 12 7 17 6 19 21 designated as talcs Not available Not available Approximately 1972 September 1972 Not available April 16, 1973 May 1973 Not available Products designated as powders (talc on label) 4 December 1970 18 Not available 20 December 1970 5 February 1973 16 Not available Products 1 14 IS 9 n 13 2 10 designated as powders (or dust) Between January 1968 and July 1970 October 3, 1970 Between October 1970 and March 1973 February or March 1973 July 1969 July 16, 1970 Not available Approximately 1972 CONSUM E R T A L C U M S AND POWDERS -13 l ea.-x into platv fragments. This facile cleavage, with resultant high ;e area, and its softness, small particle size, and whiteness confer tale its usefulness as a cosmetic material. GEO LO G ICAL OCCURRENCE OF TALC Taic rocks (including those commerciallv worked) are formed bv ss'.era: compiex geological processes reacting upon manv possible, cnemaa.h- diverse preexisting rock types. Hvdrothermal alteration of magnesia- CC 51ioa-rich ultramafic rocks, under a range of low-to-moderate tempera- x,ms and pressures, may produce talc. Thermal metamorphism of silica t e - " dolomite [C a M g (C 0 3 G ] will produce talc as well. These processes, "o.vever, also commonly result in the formation or a num ber of other coexisting mineral phases, predominantly hydrous magnesium silicates. Some of these, for example, anthophvlhte, tremohte, and serpentine minerals (including chrysotile), occur as microscopic intergrowths with :m;, as macroscopic nodules, or even as discrete zones within or adjacent :2ic j j able 2). Taic rock is therefore generally not monominerallic but s aften'a mixture of minerals that may vary widely with reSDect to kind ar.c quantity. Phi rgopite, a magnesium mica, and chlorite, a group of on,nera is related to the micas, are also commonlv associated with talc. Seme of these associated mineral phases are asbestiform amphiboles and :nr\sot1e (see discussion of the terms asbestos and asbestiform in ycnendix A ). Conversely, talc has been described as a com m on accessory m neral in commercial asbestos deposits (Hurlbut and Williams, 19zo). Taic deposits mav be zoned, with different mineral assemblages ? n . sicalh angmg in occurrence and proportions over extremely variable T A B L E E. Minerals that L o m m o n iv O ccu r :;n T a i c D e p o s i t s M in er; C ^ ro o n a :e t A m p m o o ie s Se-pe nu ne Phase Calo.te D oionu e Magnesite T remonte" A ntnoonvllite' Antigorne Chr'w om e (uncom m on, ^.arone (uncom m on . O u aric VIil l L-g , om ogopiie Cnicr.re, e.g , t e n i v n c -M'-ocmvlVte _aC03 CaMglCO- X MgCO- Ca- ,Mg< S o 0 Z2 O h L ' FeiVlg; ,, S u 0 ,- '0 H ) : Mg , S i : 0 . O H )^ VI g , S i - 0 : *' 0 H ; ,, VI g, S 1: 0 -10 H ) _ 5iO. K ..M g ,- iy S u A l.O ^ ,, :S :,A I).0 ,,, A 4 Si. 3 : , 'O H m r X X o O .re "c t n- ?SK A. IV R O H l ET AL. distances, ranging from centimeters to tens of meters. iVlinerai phases in such deposits may include talc plates and fibers, tremolite and anthophyllite fibers, intergrowths of amphibole and talc, serpentine minerals (which may include chrysotile), and free silica (quartz) (Ross et ah, 1968). The fiber intergrowth is often such that even extensive beneficiation may not yield a pure product. Thus, where fine-grained intergrowths of talc and tremolite occur, the processed product will likely contain residual tremo lite. Further details concerning the crystal chemistry, structure, synthesis, and geological occurrence of talc are found in Appendix B. IN D U ST RIA L AND COSMETIC GRADE TALCS it is generally recognized that various commercial grades of talc are marketed in the United States (Appendix C). Hildick-Smith (1976) has stated that a talc suitable for pharmaceutical purposes, used in cosmetic and toiletry products, contains at least 90% talc mineral and no detectable asbestos. Such stated compositional restrictions are not placed on indus trial grade talcs. One study demonstrated that a number of industrial talcs contained substantial quantities of tremolite, up to 87% by weight of the sample (Schulz and Williams, 1942). In 1968, a study (Cralley et ah, 1968) of 22 cosmetic talcum products demonstrated fiber contents ranging from 8 to 30% by count with an average of 19%. The fibrous material was predominately talc but probably contained minor amounts of tremolite, anthophyllite and chrysotile as these are often present in fibrous talc mineral deposits. With the exception of 4 of the 22 cosmetic talcum products analyzed, the levels of free silica, cobalt, nickel, chromium, and manganese were generally of a low magnitude and within a narrow range. . . . The levels of silica, chromium, and nickel in these four products are sufficiently high, however, to be of concern in their potential to cause disease. Thus, as late as 1968 some consumer talcum products marketed in the United States contained asbestiform minerals, free silica, and trace metals. HUMAN D ISEA SE ASSOCIATED WITH TALC EXPOSURE For nearly half a century a number of reports have shown that occupational exposure to talc dust is associated with a fine diffuse interstitial lung scarring known as talcosis. Fibrous talcs appeared to be more pathogenic than platy talcs, producing in addition to talcosis, increased risk of malignant tumors in exposed workers (Kleinfeld and CONSUMER TALCUM S AND POW DERS 259 Messite, 1960; Kleinfeld et a i 1967). Studies concerning the biological consequences associated with talc dust exposure, including cancer, are referred to in Appendix D. OBJECTIVES OF THE PRESENT STUDY Twenty-one samples of consumer talcums and powders, including baby powders, body powders, facial powders, and a pharmaceutical talcum, were obtained at retail stores in the New York City area. These samples were acquired and studied during the period 1971-1975 (Table 1). The major purpose of the study was to determine the mineralogical and chemical composition, with particular emphasis on the quantitative determination of tremolite, anthophy 11ite, serpentine minerals, and quartz. Another objective was to establish a base line for consumer talcums and powders, based on a sampling of products available during the period 1971-1975. This base line provides an index for evaluating possible changes in subsequent formu lations. METHODOLOGY AND RESULTS OF MINERAL AND CHEMICAL CHARACTERIZATION The analytical techniques employed for mineral identification and quantification included optical microscopy, transmission electron micro scopy with selected area electron diffraction, X-ray diffraction, and scanning electron microscopy with X-ray analysis capabilities. Chemical determinations (bulk chemistry and trace metals) were made with a number of standard instruments and geochemical techniques, including spectrophotometry [S i0 2, T i0 2, A120 3, total Fe (F e 20 3 by difference from FeO), P20 5]; atomic absorption (MnO, MgO, CaO); flame photo metry (Na20 , K20 ); wet chemical assay (FeO); weight loss, volatiles (H-,0, CO-., organics). X-ray fluorescence was used for all trace metals (Bowes and Langer, 1974). Optical Microscopy Optical microscopy is a conventional technique for the identification of minerals and for the study of mineral relationships. A microscope equipped with bright field illumination and polarized light optics was used to analyze the cosmetic powders. Approximately 0.5 mg of powder was placed on a precleaned glass slide and immersed in index oils of known refractive indices. These were checked on a refractometer. The information obtained on particles with this method included most of the measuiable optical properties, including indices of refraction, extinction angles of fibers, seneral morphology, and size characteristics of mineral phases (Fig. 1). In coarse-grained powders, fibers could be identitied (tremolite, antnophvllite, talc). Two samples contained cornstaich, easily lecognized r - '- '- ' M S ? - A`<; V s.`jyK*vf. < 0 vr 1 - -,4 . $>, -*2$. ^ .. 'r ? < 7 '5^4>.. y . se- - '",/ T*i* V-\ j # -: ^ -1*ir *'*; -'r v ;'.'r ' - - ',v- - J w S ? 4.? Q^i- V:i-ir _ *V w../P sVi'-y" '- .x-.` * rc^ .j.A i" it .-?'. }yj?: ''-T; ; #Kv -^ A * T ?V ?.^v 3 ^ 4 ? - :i6 F IG U R E 1. Optical photomicrographs of cosmetic talcums and powders giossK contaminated with asbestiform minerals. Photos obtained in plane polarized light (A-Fi and between crossed polari (G). Scale in (A) tor all photos. Fibers shown have optical properties consistent with tremolile (Tri and anthophyllite (An). Quartz grains (Ou) and calcite fiagments (Ca) are also shown. Most tremolite fibers tend to possess smaller length-to-width ratios than anthophvllae. Tremolile is observed as fragments (C). Photo obtained between crossed polars (G) also demonstrates tne presence of fibers in the matrix material. Asbestiform length-to-wirjih ratios -neasu'ed up 'o CO:! ,F, 260 V| 261 CONSUMER TALCUMS AND POWDERS morphological and optical characteristics. One product consisted [eel' of cornstarcn. i- most samples, however, the powders were too fine grained, with r:,:,e dimensions significant^ less than I 0 am, tor the technique to Do m't: The limiting factor for Determination of optical constants, and n_e *or identification of particles, is the resolving power or the cwscooe The presence of taic ribers, whicr, mm; have ^indices of c a t : on similar to amohiboie tremoiite, anthophyllitej ubers, also n 'cuncs analysis. Therefore, although this technique is an excellent agnostic instrument in some instances these restrictions limited its usefulness. __ _ . Otner investigators have experienced similar dirnculties t o r example, a studx of the asbestos content of talc Stanlev ana N orw ood , 19 /3 i mem was difficulty in applying optical m.croscopy to the problem. The sumors concluded that optical microscope anile it works well on pure samples of fairly massive nber ength from 3 to 5 microns, our observations bv transmission ce c tr o n microscops have shown that natural/)' occurring .,sbesti *3/777 m inerals often he below the working resolution capabilities os' the light m icroscope and furthermore while massive Tiber cundles can often oe observed by either light ^or electron microscopy the observation or individual ubers smaller than 0._ 0.2 micrometers often wiil require the high resolution capabilitv of the transmission electron microscope (emphasis added'.. mrther stated mat " light microscopy was heiptul only in screening ,es with large part.cles and high concentrations of objectionaoie tomparing the results of optical microscops with those ot^quantita T-rCV m raction and electron microscopy we observed that large : e rs or fibers go undetected. In addition to 'the restraints of ^resolution -ed o'- mht microscopy, another maior ddrraawwbbaacckk rreellaatteess ttoo the modenev of asbestiform minerals to cleave or break along planes o. ess when thev are crushed, producing large numbers or small oners xample light' microscopic examination or a taic sample ino. 3', 'contains over 7 T tremoiite Nee Taoie -t), demonstrates the presence ,,er,| T a l e n t s that are p n m aniv not asbestiform ,'F,g. : C, Mow* N a t r o n m .c ro s c o c c examination or the same sample demonstrates vane of the suomicrosccpic tremoiite particles are ribrous see rig. "->nmraern m rolvm g the determinat.or m the relative m oporoorw 262 A. N R O H L t T XL X-ray Diffraction The application of X-ray diffraction analysis in step-scan mode for quantitative determination of asbestos in talc has been described in detail (Rohl and Langer, 1974), including the selection of talc and asbestos reference materials, the preparation of standard dilutions of asbestos minerals in talc to ensure sensitivity and reproducibility, the selection of characteristic X-ray reflections to be scanned, and instrumental technique. Selection o f talc mineral standard. Screening of various types of talcs for use as reference material was made by X-ray diffraction and trans mission electron microscopic analysis. A continuous scan was first made to identify the major mineral phases present. Talcs that showed the presence of any serpentine mineral, tremolite, or anthophyliite were eliminated as reference materials. The possibility of false negatives for these minerals was checked by step scanning the diagnostic reflections (Table 3). Further verification of the absence of asbestiform minerals was made by trans mission electron microscopy. These techniques permitted the selection of a matrix talc that was completely free of asbestiform minerals. Chlorite minerals are hydrous iron-magnesium silicates, frequently associated with talcs. Their presence may interfere with the detection of serpentine minerals, both platy (antigorite) and fibrous (chrysotile). This is particularly true if they are present in equal or larger amounts than these 14.2 A (001) 7.1 A latter minerals. Two intense basal reflections at and (002) are characteristic of chlorite minerals. The latter reflection occurs (002) (7.3 A). 3.66 A close to the reflection of serpentine minerals The (004) 3), reflection of serpentine was selected as diagnostic (Table since (004) (3.53 A) the lower intensity reflection of chlorite in this region was found not to cause interference. Selection o f the asbestos standard. Reference samples of pure asbestos minerals were obtained from various mineral collections and from the International Association for Research on Cancer (A R C ). These were screened for purity and particularly for the presence of interfering contaminants according to the procedures previously described for talc. Two different specimens of chrysotile were used as reference materials: a triple air-jet milled sample from the Jeffrey Mine, Quebec (provided by the Johns-Manville Corp.) and a specimen from Coalinga, California (provided by the Calidria Division, Union Carbide Corp.). Sample preparation. Among the variables that strongly influence the precision and accuracy of quantitative X-ray diffractometry are particle size, preferred orientation, and surface flatness. Variation due to particle size can be minimized by crushing and screening the asbestos and talc standards to ensure a uniform size distribution, with an effective crystallite dimension on the order of 5 jum or less. The effect of preferred orientation is more difficult to control. The tendency for preferred orientation is largely the function of mineral cleavage properties. Both the talc and the asbestos minerals have excellent cleavages, platy in talc and 1ER T A L C U M S AND P O W D E R S ,'fc D ^ ' ^ i n a ' j o r or Asoesiiio: O'^a-ta Mineral Diiase Cr,<"'so n ic Quartz f^ c n o iita - noc^ or j;a enos::a repeat on : vl ,,nL-jnsi'n. 100^-1 - .;r- 5u : 5-25 0 : ] h' 1 AJ. 1 A 5? z-oC.o 1: 10i ! 00 i G.0-1 ' Fo ran t m ineiui in taie m a zorrebDonuine of rerlection J r r . sot 'le Qu^rrz 0 . :n : T r e m o 111 e % m : o o U3 0.9 2 0.25 2.5 5 u 5 3 QC '.0 ` AA Q o c; 0 03 Q.OE 0.2: 5 0 i 0.0 20 0 ^ 5 u 30 0 40.C - 2/' ^ 3 Ta i 1 9 30 r 3 "'0 16 90 - - 0 5 2 2 3.7 1 ? 5 G 10 0 0.30 0 93 0.5~ 1 Ac i oa 0 00 CO O c i O 01 C) o1 A5ni :m.soooun!a.lue = = Ai ea Area -.0004'' = = 2 1 00 207' 0 43 ' : An' mc'M 0 52 0 50 9 : = = = 0 0 0 993S 3 fi 'j7uAeni toa'i te = = Area i ' Are;. 'T - =--023 t Q: L" --- .04 R4` m0 9S D etection limit :0 0,-oC 0 ....... -c -.- ; ; . e ; l'n i,s : a r - e . f M ie - , ''omu r"o`n'iO j i , zraDn" iU'. mjibe-'-.nii. man ntep-scan, 2 02" 2 n a: 2,000 mJ l, \ i , 4:' , \ " : 0 t . A. s a n i t a t i o n cou nter. -nat. --pr , --n- \ -- 'v . V. ic t:a , ,eveO, -o ntm uous counts Axed -'Cl , .can. 1 R n cn b o n cJrai nae\ .. , OaoextacJ m .ab u re m e ru s o. a. .rm.sc j,nnu-*a.w .-j, ., w.cbs w i . i -- Duooiu.r o amm et er ma iu jc e L sv^.agt lai.o n or a J 3 _-u o f 'n. * os n -OH'22 -ererred c-so af memohte, amhophv Une. and chrvsotiie -'seejZohi a-j. pin p1 | a tie m p t:n ca lo reduce or eliminae die e .ecn eneomt'-on^n X-r^ analv Os, a cumoer of sanople o. eoaraaon nn-.-,.n e n,-T *oc`iraaues hve neen developed 'Bragg, . 96, , ormdlev Q Q Q , , ' vi6 ' C J I . : '- , ' 56 , Klug and A,exauce- Ihe-i m me n O O ^ , the; e recnruues ,er= :es:ea, buijaone aas x o n c n ^ r o i ia. 26-1 A. N. R O H L ET A L Tne reproducibility of reflection intensities was also greater than other preparation techniques tested. Binary dilution standards of chrysotile, anthophvllite, and tremolite in talc were prepared gravimetricallv. Asbestos fiber concentrations were prepared initially at 5.0, 4.0, 2.0, 1.0, 0.5, 0.2, and 0.1%. Fifty milligrams of the talc-asbestos mixtures were homogenized in 10 ml filtered water utilizing ultrasonic energy. This slurry was poured into a 30 cc syringe and filtered through a 0.22 fim pore size membrane filter. To prevent stratification due to differential particle size and density effects, the syringe is held in a horizontal position, rotated, and shaken during filtration. The residue forms a fiat cake of about 0.5 mm uniform thickness on the membrane filter. When dried, the sample is affixed to a glass slide for X-ray diffraction analysis (Rohl and Langer, 1974). Selection o f X-ray reflections. Because of crystal structure similarities in the minerals being studied (i.e., tremolite and anthophyllite), consider able overlapping and interference of X-ray reflections occur. The low symmetry and consequent complex X-ray diffractograms of such minerals as talc, chlorite, and mica, as well as possible interferences from admixed phases such as kaolinite, make it necessary to select a reflection or set of reflections for each mineral component that could be used as an index of the amount of that mineral in a mixture. Such diagnostic reflections were selected by referring to standard X-ray powder diffraction data. These diagnostic reflections were step-scanned at 0.02 2 theta in a fixed count mode (2 X 103 counts). Precise positions and profiles of the diagnostic reflections were determined. In the fixed count mode, each of the angular intervals selected are scanned with equal accuracy. Thus weak reflections can be determined with equal precision as high intensity reflections. The statistical accuracy depends only on the total number of counts recorded, and the counting rate selected gives a percentage probable error of about 2%. Profiles of the diagnostic reflections, plotted as a function of number of counts vs. 2 theta, are measured with a compensating polar planimeter. The intensity of a reflection is proportional to, but not necessarily a linear function of, its concentration. Other factors that mav influence reflection intensities include instrumental conditions, particle size, degree of pre ferred orientation, sample thickness and flatness, and absorption character istics (Klug and Alexander, 1954; Rohl and Langer, 1974). Figure 2 shows calibration curves obtained for chrysotile, anthophyl lite, tremolite, and quartz using the step-scan technique. Measured areas of diagnostic reflections are plotted against percent dilution in talc. As indicated in Table 3 tremolite may be determined at levels as low as 0.10% by weight, chrysotile from 0.25 to 0.50%, and anthophyllite, as low as 2% in talc. It is important to note that the limits of detection given in Table 3 are higher and based on a best fit regression analysis. For example, regression analysis indicates that the detection limit for chrvsotiie is 0.7%, whereas from 0.25 to 0.5% can be actually detected, , M E A IMS AND P O W D E R S 26: i remoi;to ShrySOTi < 20 10 A n th o p n y ll ite I224557S9 1C 5 10 15 20 25 30 35 40 45 Percent asoesTiTorm m inerals t , talc P e rce n : asbestirorm a m p n i o o i e - 'Q u a r t: .n rate FiG u R 5 mion o -'iDCitiiornt cj 'npniDoies and cuenr ,n ioio encing o r Denticle size, degree of c rvsiallinitv, etc i he changes m :e W she owes end of the curves are not reflected so that axial "'cents are exaggerated on ;ne nigh end oi t ie abscissa. 3 \ -sing X-raC diffractior ,n the step-man mode, Sta n ley and N or - ' t o were able to detect a minimum ut 0.25m tremoiite m taic 1 2 minimum of 0.5 w cars sot.le and the other asbestirorm minerals ...ever. s..cn :o\\ levels or o u r s o t ile were not detected when oniontc s:en scanm nc The contents of the containers weie thorough i\ mixec 2 - 5arricu, Sautter to mom stratamaucm e je c ts Ahcuots of er.cn, i (j T/y VACr0 e n c a reu asms tne memicai methodologv oesermed 2reodr; n o m a the ailution standards The 'Iter-mounted samples ,ve iled scannea c m t " e cio metric intervals diagnostic .or the ;ar:-: instrument operating conditions r aicaiv z-nc the dilution standaics r ' r., -w .me "er !ection areas atter peak a :a n im e a ' . i w tve'gnt aoncniLi --t St* S8-! 266 T A B L E 4. Sum m ary o f Mineralogical Com position ol 21 Consumer I alcums and Powders Sample no. Minet als 1 345 6 7 8 9 10 1 1 12 13 I I 15 laic Chlotile Pltlogoptte Calcilc Dolomite Quai 1l Kaolin riemolite Anthophyllile Chrysotile I'yiophylltte Rutile M" l> - 5.5 2.7 1 1.4 - M MM M M P MM - P Tt P P - PP - It - - - -- P Tr -P - - -- ~ -- -- - 1.6 _ ~ 1.9 35.1 - - _ - -- Tr P - -- O.S 0.4 74 - - _ -- 4.9 - - __ - - - - - -- - - - P - _ Tt -- - - M M M P P P P P - P P P ~ - __ - 4.0 - 10.3 - - ~ 4.6 - - <0.50 ... P - - M M P P P P - 3.0 - - - 0.1 ~ 2.4 <0.50 ~ " - "M - ma|ot ; I' = present; 1r = trace. * Hi git K , 0 and NaaO suggests lliat this phase is a mica (muscovite/biotite). 16 17 18 19 M M M M I' r I' - - I5 2.0 - 1.6 2.0 3.0 0.1 - . 5.2 2.1 -- - * c 1jum 0.5jum D F IG U R E 3. Transmission electron micrographs showing range in morphological characteristics of asbestiform tremolite and anthophyllite in talc. The entire range of morphological variations observed for these minerals is observed in the asbestos standards: rectilinear fibers with parallel ends and edges (A ); step-cleavagc ends (B ); unit fibrils protruding from ber body, (C); curvilinear fiber with amphibole cleavage end (D); high length-to-width ratio fibers (E); fibers protruding from interiors of talc plates (F ). All of these morphological variations and forms (A-E) have been described in anthophyllite and tremolite asebestos samples. The amphibole structure was confirmed in all cases by selected area electron diffraction characterization. Scale as marked. Micrographs obtained on a J E O L JEM 120 U with an accelerating voltage at 120 kV. 268 CONS L M E R T A L C U M S AND POWDE RS 269 - G O R E 4 Transm ission electron mtcrograons or cosm e:K a m p k composed prim arily or nates an occ asio na l large rail- ober , B , C ) , taic with manv . M l rioe: D i ocaic is tne same m ^ 3 l iH3 1n iC] m o D'> 44 ^eiecica area electron cj i i! 1action p atterns o btained on fioe^s .,'c ^ ' s t fi' .i %ia ii`c m' i- 'q a 4 \pi(i -U ! r i 1 a .: -o n tam :nc samples -v U e : o c n r7iu. -o-. ' `nc go ms te n a e c to r:.rq 'Pip I ; ;o b d m m greatest : o e r ; c " l 1mrograon oDtainpa on a ! E C L 'E M >-0 U w o n ^r. i . . . ; l r a i .v n o O w e : ' 2 0 k V ;o e::P' V '; :\ `c that 'he oieseoce of amphiboie .r me JiOrae: m E eotron microseom omrriC-'ie o t rs were nresem n mm pies Town to be \ it,e not 2no ot ;ta tive. F IG U R E 5. Transmission electron micrographs and accompanying selected area electron diffraction (SA ED ) patterns for cosmetic talc ample*. The talc plate (TPJ m ,A) hows t\pical polvgonal cleavage and diffraction connast contours lor the mineral species. The auom pam iny SA E D pattern displays the characteristic recipioc.il ab* plane pseudohexagon.il s' mn'etrv roi talc Talc a and b directions indicated on (A). Measurement ol pattern indicates a p 3 a icpeat alone a and a 9.1 \ repeat for b* (measured at 1110|l Talc fiber (T F ) in (B) displays in s u la r ends and nonrectihnear edges. The SA E D pattern is also pseudohexagonal, but *ome ieilection inien'siues [e.g., the (060), (0.12.0)] are more pronounced This mav be due to both orientation and siiuei'irjl effect*. The curled talc plate (CT) in (C) display* an incipient Debye-Schei rei ring pattern (the effects or both folding over of talc and small associated grains). The amphiboie nbe' iD ' w j i Jm racted onlv on one of the protruding unit rioi'n T 've . axis is shown, i.:tn cp.-t c.o A. Areas where diffraction patterns were obtained are indicated bv location .ndc*, particle* were photo graphed at the SA E D magnification `"26,500. Scale is the same m A-C, *caie *n D as marked. Micrographs obtained on a JE O L JEM 120U with an accelerating voltage at 130 k . 270 07 n A. N. R O H L E T A L comparison with known dilution levels of chrysotile in talc observed by electron microscopy, the levels of contamination of chrysotile in the two samples correspond to about 0.25-0.5% chrysotile, which was suggested by the X-ray diffraction results. The chrysotile fibers were all shorter than 2 pm and the diameters less than 0.2 pm, explaining why they were not visible by optical microscopy. Chemistry of Consumer Talcums and Powders The bulk chemistry (Table 5) and mineral contents (Table 4) of the talcums and powders complement each other in that one data set implies limits for the other. For example, analysis of sample 1 shows the presence of FeO and CaO (Table 5). Recalculation of these oxides into values for the empirical formulas for tremolite and anthophyllite indicates that sufficient quantities are present to account for the presence of these minerals (Table 4). An appreciable decrease in S i0 2 , which should normally occur, was not observed, because of the occurrence of over 5% quartz content. The A l20 3, Na20, and K 20 are reflected by the presence of chlorite (probably the penninite phase). Variations in oxides were also observed in the other samples that contain amphibole minerals (6-8, 11, 12, 15-17, and 21). In these samples, a number of other factors account for the wide variations in oxide percentages: in 6, the presence of chlorite T A B L E 5. Major Oxide Content of 21 Consumer Talcum and Powders0 Major oxide 1 SiO. TIO,, A LO j Fe,, 0 3 FeO MnO MgO CaO Na, 0 K,,0 P: 0 5 Volatiles' Total 61.99 0.10 0.82 0.00 1.51 0.00 29.60 0.40 0.07 0.02 0.01 5.36 99.88 Sample no. 2b 3C 4 5 6 7 0.00 0.00 1.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 98.70 100.00 62.68 0.14 0.37 0.08 0.32 0.00 29.83 0.04 0.03 0.02 0.03 4.66 98.20 58.72 0.04 0.24 0.04 3.03 0.00 28.25 0.10 0.03 0.02 0.03 5.38 95.88 61.94 0.03 0.45 0.03 0.51 0.01 30.19 0.04 0.05 0.02 0.01 5.51 98.79 52.95 0.17 1.16 0.02 0.86 0.00 29.02 3.46 0.00 0.05 0.13 10.32 98.14 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 8 71.93 0.19 15.73 0.10 0.34 0.00 2.95 2.37 0.48 1.37 0.05 5.25 100.76 9 58.68 0.08 0.58 0.12 3.12 0.00 29.23 0.17 0.00 0.00 0.00 5.34 97.32 10 11 51.65 0.71 1.45 0.09 0.34 0.00 27.90 4.75 0.03 0.00 0.05 9.72 96.69 49.48 0.22 2.32 1.23 0.07 0.00 25.67 1.61 0.42 0.19 0.01 10.41 91.63 ^Weight percent, recalculated as oxides, following standard petrochemical procedures. The bulk analysis of the powders reflects the combined mineral content after additives were extracted using water, dilute HC1, acetone, benzene, and ether. * Analysis of 2: 98.7% = starch -r organics and volatiles; 1.3% = A l.C q (aluminum chlorhydratc.M. c Standard talc used as matrix for fiber standard dilutions. CONSUMER TALCUM S AND POW DERS 273 sharply reduces the S i0 2 content and elevates the AUO3 content. The presence of the carbonate mineral calcite Increases the expected CaO and volatile contents (the latter includes C 0 2); in 7, the high T i0 2 is reflected by the presence of the mineral rutile (T i0 2); in 11, the high CaO, moderately high A U 0 3, and low S i0 2 contents reflect the presence of calcite, chlorite, and tremolite. Several of the above samples (numbers 8, 12, and 15) require special evaluation. Sample 8 is extremely high in S i0 2, AUO3, Na20, and K 20 and extremely low in MgO content. The chemistry indicates that this material was not derived from a talc rock, but rather from one rich in alumina and silica. The mineralogy reflects this, as do the trace metals (see trace metal section). The amphibole minerals in sample 8 are associated with both pyrophyllite [Al4Sig 022(O H )4] and quartz, both present in substantial quantities. The mica phase is not phlogopite, but muscovite, accounting for the presence of substantial quantities of K 20 and Na-i 0. A plagioclase feldspar was also detected in the mineral phase. S a m p le 'l2 is very high in A l20 3 but extremely low in S i0 2, apparently the result of high chlorite content as well as substantial amounts of pvrophyllite. Sample 15 is low in S i0 2 and extremely high in volatile content, reflecting the presence of both carbonate phases and organic additives. ... . The trace element analyses (Table 6) show distributions that are in accordance with the known behavior of trace elements in minerals. With T A B L E 5 (contiriued) Maior Oxide Conten of 21 Consumer Talcum and Powders" Sample no. 13 --J U.) IO 0.1 8 9 34 0.0 1.22 0.00 29.S3 0.69 0 03 0.05 0.21 i 0.26 99.13 53.83 0.11 1.74 0.03 0.70 0.00 27.14 5.49 0.07 0.00 0.14 10.31 100.06 14 57.47 0.1 1 1.65 0.02 0.65 0.00 26.98 5.52 0.05 0.02 0.13 10.41 44.33 0.07 0.69 0.00 0.62 0.00 23.S3 3.67 0.35 0.07 0.10 21.34 98.01 95.62 16 62.26 0.06 0.45 0.1 8 1.04 0.00 30.00 0.13 0.09 0.05 0.01 5.92 100.19 54.45 0.10 4.26 0.04 1.41 0.00 30.79 1.13 0.09 0.02 0.04 7.54 99.37 18 59.93 0.10 0.79 0.00 0.84 0.00 30.40 0.50 0.09 0.02 0.1 3 5.65 9S.45 19 20 21 58.54 0.1 S 1.1 1 0.00 1.3S 0.01 29.S3 1.13 0.00 0.00 0.00 5.94 9S.21 62.19 0.08 0.69 0.00 0.81 0.00 30.19 0.43 0.07 0.00 0.13 5.14 99 73 56.34 0.12 1.35 0.02 1.39 0.00 27.90 1.5 3 0.07 0.00 0.02 9.99 98.73 57.34 0.21 2.30 0.11 1.05 0.00 27.44 1.69 0.10 0.10 0.70 3.03 98.20 61.49 0.01 1.20 0.38 1.07 0.00 3 0.54 0.46 .0 0 100 11 J Average of 20 talc samples. Average o f 8 taic analvses in Deer et ai. I ! 962) oianies are lost on ignition (to tal H .O , , uiganics, and other vo laiilesl T A B L E 6. T i ace Elem ent Content o f 21 Consumer 7 alcum and Powders" T i ace metals Ba Ce Cl Co Ci Cu Ga La Nb Ni I'b Rb S Si Th Zn Ti 12 <10 __ <10 -- 210 -- 35 -- 310 _ <5 -- <1 . . <10 - - 7-- 710 -- 8 5 235 ,, 10 _ <5 _ > ... <10 - 3 4 <10 <10 130 <3 28 <5 4 <10 8 17 8 5 130 10 <5 85 <10 <10 <10 135 8S 600 <5 <1 <10 8 172 <5 <5 120 to <5 37 <10 5 6 7 8 <10 <10 185 <3 16 8 <1 <10 11 27 <5 <5 2230 10 <5 18 <10 <10 <10 200 <3 23 <5 1 <10 7 13 <5 <5 440 20 <5 12 90 <10 <10 140 <3 24 <5 <1 <10 9 10 <5 5 150 30 <5 IS 10 50 10 130 <3 <15 9 20 40 14 <4 49 45 305 160 6 20 190 9 <10 <10 115 88 820 <5 <1 <10 S 2210 7 <5 155 <10 <5 37 <10 Sample no. 10 11 12 13 990 <10 125 <3 25 <5 1 <10 7 34 <5 <5 425 25 <5 > 10 <10 <10 115 <3 18 <5 3 <10 6 4 1 7 <5 110 100 <5 > 10 <10 <10 120 <3 24 <5 13 <10 18 1 1 5 <5 280 <10 <5 > 30 <10 <10 430 <3 38 5 2 <10 7 10 7 <5 485 15 <5 J-) <10 11 15 <10 <10 435 <3 49 8 1 <10 7 17 12 5 595 20 <5 1 1 <10 <10 <10 410 <3 41 10 2 30 5 10 8 5 535 20 <5 0 <10 16 17 18 19 20 <10 <10 165 21 340 13 2 <10 5 460 6 5 320 <10 <5 IS <10 <10 <10 140 <3 32 6 7 <10 9 14 9 <5 140 15 <5 2/ 50 <10 <10 130 4 30 7 3 10 8 20 7 5 160 10 <5 8 <10 <10 <10 1 10 <3 28 6 2 <10 9 28 8 5 105 10 <5 1 1 <10 <1 0 <10 120 <3 25 6 3 <10 9 19 5 5 155 10 <5 3 <10 21 <10 < 10 130 <3 4 2 13 <1 <10 7 12 16 10 70 1 5 <5 *,. <10 274 " Values in pails per million. The symbol < indicates the limit of detection of 111c analytical method. The symbol i- indicates concentrations ol 7n are greatei than 1,000 ppm. CONSUMERTALCUMS AND POWDERS 275 rue crostai lattice of a mineral acting as a sorting mechanism for cations, tv_ cations can enter a crystal structure providing they have appropriate s,ze and charge. These phenomena appiy to major as well as minor o eme.nts Thus, barium 's present in large amounts in sample 8 , which has ^ - ah KAO content ( 1 3 7 % ) . Since barium and potassium have similar awe radii, barium is easily admitted into potassium minerals, such as ~;:as and feldspars (both found in 8) Rubidium and strontium are also cmcenea in sample 8 , since these metals also easilv substitute lo r potass, urn. Gallium is found in large amounts in samples 8, 12, and 17. These samples are also very high in A U 0 3. Gallium has the same ionic marge and radius as aluminum and, in fact, is found only in aluminum bearing minerals. _ in four samples ( 1 , 4 , 9 , and 16) there ate significantly higher concentrations of cobalt, chromium, and nickel than found m the other samcies These four samples also have high contents of FeO (Table 5). The association of these four transition metals has been observed before in certain geochemical environments, particularly in ultramafic rocKS. Since tarns derived from the metamorphism of serpentines and peridotltes ultramafic rocks) are considerable enriched in FeO (Deer et al., 1962), it s uaelv that the divalent cations are substituting for iron in the brucite as e- of the taic. D ISCUSSION AND CONCLUSIO NS Talc used in the United States represents a wide range of mineralogical ^stances. Industrial grade talcs are obtained from different rock types or " g n s variable mineral composition with the result that the mineral talc ac:uallv be a minor constituent. However, it has been stated that consumer talcum products should contain at least 90 % oi the mineral or me came name and no asoestos fiber ( Hiidick-Smith, 1976). Review or the te'seure suggests that at least until 1968, materials that weie marketed as ; m--etic talcum products did not necessarily' conform lo these crite.ia. Talc mineral mav occur in a platy form or in a fibrous form. Talc cer mav occur as a small oroDortion of tne mineral desoosit or as a - c o r constituent. Intergrow'ths of talc witn other mineral phases are 'mmon These chases mav be simDiv macroscopic zones adioining talc - - e m l or mav' occur as microscopic intergrowths within the taic. Of the - mmeraD that mav coex'st with talc, a numtaei oi asoesuform onascs mmmoni'v 'o c c u r tremoute, anthooiiy kite, and cnrvsonle have been .-cot.fieri in these deposits, in addition. *ree silica 'quartzi is a meauen. . -~^^,r , , ^ The t n c e metal content mav include elevuied evels m ticaA, H' nt between tne mineral comDOS.tion ano the 276 A. N R O H L AL. basis of mineral and chemical contents, the type of geological provenance may be ascertained. Methodology has been developed for quantitative X-ray diffraction determination of anthophyllite, tremolite, serpentine, and quartz in con sumer talcums and powders. Important factors in the calibration standard development include selection of talc and reference minerals and the selection of diagnostic X-ray reflections. The sample preparation technique is sensitive and reproducible. Dilution standards are step scanned over diagnostic reflection areas, peak areas are measured, and a set of standard calibration curves is developed by regression analysis. Samples of consumer talcums and powders are prepared and analyzed under identical conditions and compared with the calibration curves, permitting quantitative analysis of these minerals. X-ray diffraction alone cannot distinguish between asbestiform and fragmented forms of anthophyllite and tremolite nor between asbestiform and platy serpentine varieties. Electron microscopic analysis was used to distinguish between these forms. Mineralgica! characterization of 21 consumer talcums and powders showed that 10 contained measurable concentrations of asbestiform tremo lite and anthophyllite, and some also contained fragmented forms of these m inerals. Two samples contained trace quantities of chrysotile (0.25-0.5%). These observations were confirmed by transmission electron microscopy. The amphibole phases present in these talcum products ranged in amounts from several tenths of a percent to over 14% by weight. Quartz was present in eight consumer talcs in amounts ranging from 1.6 to 35.1% by weight. Consumer talcum products are for the most part complex mineral assemblages, which confer X-ray sorbing and fluorescing effects that are not equivalent to, and are usually greater than, those of the binary systems used in preparing the dilution standards. In consumer talcum pro ducts minerals such as talc, micas, chlorite, calcite, dolomite, and others tend to diminish reflection intensities of asbestiform minerals by sorbing X-rays or by contributing to background noise. Also, repeat runs on some selected specimens have demonstrated greater peak areas due to slight modifications in instrumental settings (e.g., increase in receiving slit width). Therefore, the values for weight percent concentrations given in this report are conservative. Examination of the same consumer talcum products by both optical and transmission electron microscopy indicates that not all of the mater ials fall within the definition of fiber or asbestiform. For example, one consumer talcum product that contained more than 7% tremolite was observed to contain both fragmented tremolite grains by optical micro scopy and asbestiform fiber with 3:1 or greater length-to-width ratio by transmission electron microscopy. Optical microscopy may provide useful information. However, more complete characterization can be obtained by electron microscopy and selected area electron diffraction. Using electron M s -\M) R OWDc RS ..ample, several R.mpIes cm consumer taicum producs a m free a m c n b o ie G o e r discrete c o r r talc groins, and, in jm uciis A : srnai, ampPmoie ribero were visible, ^,i onte v ib 1see r g o -\,. apparentK interm an electron race nas cem orsm atedFumi .nciwduai fiber ch em istr dC nners encouniere: i^ The I A R C Asbestos Standar; j ames j\ rbe m inew lo grai and cnemicai anaractenaation or ,1,101s, a,, iormulated prior to June '. 9 , 3 , we conclude tn,at or o- raw was nor usee exclusive!'. The presence in these r asoesoform ,,w th och viluc and tremolite, chrvsotile, and a ua n z roe need mm a regulator, standard for cosmetic talc. This , oui, o be cognizant o. toI c commexities, mineralogical and n "ature and should oroviue for adeuuate analvtlca! protocols munit orme;. \e ,, iso recommend A - evaluation be made to le neaith razaros associate w'tn the use of these products A. DhH.ViTiONS OF TERM S fXT ame acm.icd tc a group of "aturailv rlbrous minerals" amosne, erocidome, tmmoiite, anthoph v 111te cited O' ear of Mines, ;9(oe . T o term asbestos has also oeen o r r im e r r a lli e x o lc te c fibrous mays, including attacuigite Rite 'AT,warm. f 963 n ; - es cement r possible exploitation, based on r'ne scec,.u one Sicai arm anerrncT properties, determined on tmr: e .emr F m example, mgu hbei tensde strengtlp , a o e ji : jiiduc; 1 r\ , mtw eiecrncai "esistance, and cnem- ; .re mmmrt.es of asoestos \ o n c o m m e rc:a; varieties of me mat no: possess dm same dualities an the ouik eve1. I or wasim -ms seep considered :o oe me econ om ical!, r e : r errmeme Tver el al. 962, F so arm even mis ,uerc.a.'2'sis mm'- mme n a c r c c r srais .me sign:: - rvm pm-, scam mm struct maim G rtm erre ::her ;s rgm, . ., fT-rcie, cruner''e melds weil-jeimeG smgie \-ra' - e ' ,t (,p; ', , -o lecrmomes, amosiie v icier m u n o ie ^ u ' . c . v s .s mrmmscd m ta r e s . Gowexm m e n m-SA idH r 278 A N R O h . 2' AL technique). Amosite ma\ be considered es an agsregate o' u n o rierac discrete, grtinerite crvstals with onlv the c axis in common alignment Comminution of such aggregates produces nbers with cram m er istics identical to those of single crystals of grunerite that have beer, similarly pulverized. Some workers have suggested that mechanical s.ze reduction of amosite yields fibers with crystal growth surfaces ra:ner than cleavage surfaces. Since amphibole cleavate tends to parJie: prominent crystal face planes, such distinctions oa the submicrcsccoic ievel may disappear. This appears to be the caw for tremohte anc anthophvllite as well. However, because no metiods exist to extin guish between possible differences in fiber surface, we do not re*er to anthophylllte and tremollte fibers In these talcums as asbestos. Insteac they are referred to as asbestiform. It should be swessed, however mat evidence does not exist that would indicate that fibers with cm stai growth surfaces or cleavage surfaces possess lesser or greater bioiog.cai potential than fibers from commercial asbestos deposits. Asbestiform " Formed like or resembling asbestos, ribrous; . . . . (Bureau of Mines, 1968). The term Is used herein for amphiboles (anthophylllte and tremollte) seen on both light and submlcroscopic examination, which resemble comminuted asbestos varieties, on the bas.s or morphology. Essentially, when these fibers are derived from commer cial deposits we term them " asbestos" and when analvticallv identical fibers are found as noncommercial Intrusions with the mineral talc, we term them " asbestiform." The use of two terms does not imply differences that can be analytically determined. Fiber " The smallest single strand of asbestos or other fibrous materials' (Bureau of Mines, 1968). We use this term in ; broader sense For example, chrysotlle fibers are called fibrils, possessing unit diameters or about 200-400 . Coherent bundles of fibrils are also called fibers Fiber in the present text is used to denote any elongated single mineral unit visible on the light or electron microscopic level i he Occupational Safety and Health Administration has applied a 3 1 length-to-width ratio to distinguish fiber from mineral fragment. A P P E N D IX B: C R Y ST A L C H EM IST R Y , C R Y ST A L STRUCTURE, AND GEOLOGICAL OCCURRENCE OF TALC Chemistry of Talc The empirical chemical formula of talc is Mg3Sl40 10(O H )- , out ferrous and ferric oxides, alumina, tltama, soda, lime, and oxices of manganese have been reported In quantities up to several percents by j A0l) PO'A0ERS 1sa m ine cm. .-ryjr-jm-"T ^^1 to simbionte o n silicon, wherm aOU ,001200 CSC -lUcdU iCC oOS manate a.O C o mp c n,m ts or s w heat me t:;csencc i 19o 4 Stems ie anc B nu ec Stales coniai ot -, -o^terming these m w arm menu > u. L fn [D, ; ; isa i n e r i r n e '" m :nt !a1 phase trerocs i n n i e v' I 960!. One maior laic deposit o substantial amounts o T nickel, as rnuca 'ijr componenti, tam a- as>ent;al!\ 'w MaO, 63 T S iCo , and . - wructuraii\ pound water ic Structure anc Crostai Habit lui strum e comprises a sheer c>f octahearaiK c M g iO H C groups hre crumciaie lia\see;r saaaniiduwiwch,iec:d between two wwanecwailv imne d SiO_ groups .silica layers) Apical oxvgens m meem are a r e :area toward the oruc.te laver and in par: m- rotrew ^arO'UCS, wirier, warm a ooroon w: me inner Sl. act^ra. nec oduince is moiisned within the structure, so that them ,r targe on iuxmposed uni: lavers a: the siiica base interfaces, j nui :t oOTf tirhec tlalIc struecture was determined over 40 vr ago 0ndne ks , I S 4P > CO rn the repeated cell geometer and space o n I\' racemt ;v resoiv ed X-rcv single crvsrai patterns now OC trie !m ,c [''Rasxnnecr and Brown, 1966, Ross et ah, i 9 6 8 i . roo.n a r. e 10 che nr. icai and sin tcrural complexities, talc occurs with mmu n,La 0 1is ' Fora, : 9571 The development of the fibrous :10; I n e_! o ng.a:cd . rtvvstallographic maxis mav be a nani- t,f omic substitution smee as refractive index is higher than platv r-mei anc Osoorn, mo Cruner, 9-1 1 11 h cl contains no urn' V. ; hose ec; mealed forma is refer:red to >n the V ,re ab fibrou s mie o r . , la; ocserration.s with mga r3 ; m :o uci; na'- e Deer. -eoortea 'Lieolm g and Langer, 19,1") .m iron v-or. i c nt in me normali'- P ial , Cl Umile 'T .atd)oc ia tea 'Aid; men: ar "dbroar, nabli, it ,s of interest to note mat coos. red i:m- son e m be an iror-ncn form o t laic, ai warn ub c' r ':ven a 1neeaieu ike, hao 1l O runer 900' jr,nation of Talc in the Lanoraiory ot Nature -nru-nile e x t e r m e o t i weste;mo. talc ras :c ise n s'v ntnesizec r, . ~ . . . g.U- Voce: a m Br iim a r e m 'Sin water rugaom , m anc pressure parameters arc cev nee ss a r m wa r e men ; restrict- to'O "irites t i CCOCUCC 'Clal'T'Cl s o aw m'Wtail aa!t o n P OCUa-.s. - , ra v : W 4 f r,`'rj('R. Lbt t 1o m o o o soa s wane; u e nomi -r . -, m g r : cm.: uns n . \ o a og CL O O WWW ./' . "w-au mcaw 'c ..a.o a. " tc, o; '' i u O W S W m, wm 280 A. N. R O H L E T AL Nature of Talc Plates Electron microscopic examination of talc minerals demonstrates that single talc grains consist of contiguous single crystals, mosaics of dis oriented crystallites, and intergrowths with other mineral phases, particu larly tremolite (Kleinfeld et a!., 1973;Stemple and Brindley, 1960; Wright, 1960). Selected area electron diffraction patterns obtained on these objects display, in order, single crystal arrays, Debye-Scherrer rings, and superimposed complex patterns characteristic of intergrown single crystal phases. Talc and Mineral Intergrowths Tremolite is one common intergrowth in talc, and it requires relatively little energy thermodynamically to occur. Replacement of magnesium by calcium in the brucite layer may lead to structural as well as chemical modification (Bragg and Claringbull, 1965). Rotation of unit tetrahedra in talc forms double chains from sheets, readily accomplished by substitution of Mg(OH)2 by Ca(OH)2. The bulk chemistry is thereby changed from Mg6Si8O 20)(O H )4 to Ca2Mg5Si80 22(0 H )2. The final structural array is remarkably similar in both materials; the crystallographic o-axis of talc is approximately 5.26 A, which corresponds with the c-crystallographic axis of tremolite (approximately 5.24 A); the b-axis for talc is approximately 9.10 A, which is equal to the b j2-axis of tremolite; the c-axis of talc, approximately 18.8 A, is about equal to twice the a-dimension of tremolite (approximately 18.2 A). The monoclinic stacking angles, the beta-angle, are within a few degrees of each other. Intergrowths may form in which amphibole formation is not complete so that a mixed phase exists, referred to mineralogically as " talcboles." These are not as rare as once believed and may even be common in the more complex talc deposits. A P P EN D IX C: IN D U S T R IA L AND CO SM ETIC GRADE TALCS Studies have demonstrated that industrial talc often consists of a variety of minerals, the utilization of which is based on physical properties rather than mineral composition (Hogue and Mallette, 1949; Schulz and Williams, 1942; Thompson, 1974; Wells, 1965). Early analyses of cosmetic talc also showed a wide range in mineral composition. Of six such products examined in one study, only 6-47% by weight of the inorganic material that constituted the product was the mineral talc; 14-51%, serpentine minerals; 5-77% carbonate minerals; 0-trace, quartz; 0-trace, tremolite; 3-12%, other minerals (Schulz and Williams, 1942). : R ' L C MS A N D pOW PF.RS A PPEN D IX D B IO LO G IC A L H A Z A R D S A SSO C IA T ED PATH % ALC EX P O SU R E m lateral, progressive a trenohte taic n Georg )bis was observec among (Dreesserg 1933, Dreessen 35L Siegal et ai ( I Q4 studied a population of 'IG ng trerr.olitc a nt anthophv I hte-bearing taw New Y o i L state. In accMUon to me mlaterai fibrosis, d Icl ra i !,a r to those encour.terec m asoestcs workers, were observed, postmortem material m this studs indicated that asbestos O'-esent in inns tissue ere pneumoconiosis in Ororro and Levine .'1946;. , wan , i Arm reported that These findings were also reported in tremoiise millers by Davmon ,'1946:, exposure to cosmetic-grade talc pro- nivOobir ; iarcs is m workers No Quarts was datemed in ihe dusu who; con c'u d ec that talc itself was capable of producing scarring, nservation was sucnortec in studies bv Reichman ( 1944: and by : cay Jncj in a studv of taic miners and millers in Italy where me to mure taic pmduced a 10% incidence of pneumoconiosis in m %u m eus ian i , ; Qa8). excess deaths attobuted to pneumoconiosis teen reported a m ors workers in northern itaiv mining talc con : to oe free of asbest.form tlbers Ru oino et ah, 19/o/. me investigators have held that fibrous talcs m ot differentiated as - ascestov riper' a;e biologicadv more hazardous than piatv taics .ample in a mview of the literature bv Porro et al M 942 i , e _nd Gardner are rcrerred to as considering that the clinical, statu, and pathological disease states of asbestosis and talcosis are G . a , Tbere are several reoorts of the occurrence of asbestos bodies . ma assue of workers exposed to taic .'Daemon, 1946, Hobbs. < emfeld et ai.. ! 9" 3 , McLaugnlin at a; , I 949 , Porro et al,. 1943;. . nr-,, studies sussesi that nbrous talcs are more dangerous as a icsult - nciuded tsoestos fiber. For example. McLaughlin et ai. 19^9) dgers :n ta.c w th the proportion of fibers recovered rom the - 5sje of an exposed wormer A larger eonce.ntration of libers was n trie "issues as compared with the raw talc. Talc pneumoconiosis mtf rmed oy K le m rc d and Messite % 9o0: m their muds of the New state talc SlUC! v W 'lO SI ne n workers. pv Kiemfeld e t a. 1967' was demonstrated that taic accounted for almost 30% of excess d e a t h s among the talc VI Os ) r puim ' nese w e re due to the complication or However, 31"s o; the 91 deaths recorded uns carcutoma meura! wom-sarcoma, mu aaocrcatic or.ncm V m i u n c j mes.S- Hr***?*. 1 % --E.MVj,f,c2 ' 1 Er-A ' 2S2 A. N. ROHL ET AL these data indicated that a 3- to 4-fold excess of cancers existed in this group, as compared to a matched control population. ^ The biological activity of both tremolite and anthophyllite fibers has been known for some time, and both have been cited as asbestos minerals by Merewether (1930) and Noro (1946). Asbestos disease among workers (and others exposed to anthophyllite and tremolite) has been reported (Burilkov and Badajov, 1970; Kiviluoto, 1960; Meurman, 1968; Meurman et a!., 1974; Schepers, 1965; Wegelius, 1947; Weiss and Boettner, 1967). Recent experimental data also indicate that tremolite fibers are biologically active (Graham and Graham, 196/). Some investigatois have suggested that inorganic fiber fibrogenicity and carcinogenicity is limited only by its ability to reach the alveolar space (Holt et a!., 1965; Pott ajid Friedrichs, 1972; Pott et a!., 1974; Robock and Klosterktter, 1976; Stanton and Wrench, 1972). . Wagner et al. (1975) reported lung scarring in Wistar rats with pure talc, exposed by inhalation. The severity and extent of the lung scarring was comparable to that produced by chrysotile asbestos under identical experimental conditions. In addition to lung scarring, ingestion of talc was reported to be associated with leiomyosarcoma of the stomach as well as one adenoma and several sarcomas of the uterus. However, the exposure levels were high and the numbers of observed tumors small, so that statistical validation of the carcinogenic potential of pure talc and its relevance to human exposures were not achieved. There are also extensive data concerning hazards associated with exposure to silica or trace metals, particularly nickel and chromium (National Research Council, 1975). Analytical data are presented here that suggest possible disease potential and the need for investigation in these areas. REFERENCES Bowen, N. L. and Tuttle, O. F. 1949. The system M gO-SiO,-H, 0: Bull. Ceol. Soc. Am. 60:439-460. Bowes, D. R. and Langer, A. M. 1974. Petrochemistry of the Manhattan Formation. Kristalinikum 10:39-52. . ,, .. v i.. Bragg, R. H. 1967. Quantitative analysis by powder diffraction. In Handbook or X-rays, ew or-. McGraw-Hill. Bragg L and Claringbull, G. F. 1965. The crystal structure of minerals. London: Bell and Sons. Brindley, G. W. and Kurtossy, S. S. 1961. Quantitative determination of kaohmte by x-ray diffraction. Am. Mineral. 46:1205-1215. Tk , Bureau of Mines. 1968. Dictionary o f mining, mineral and related terms, e . . . Washington, D.C.: U.S. Government Printing Office. . . Burilkov, m and Badajov, L. 1970. Ein Beitrag zum endemischen Auftreten doppelsemger Pleuraverkalkungen. Pray. Pneumal. 24:433-438. Cralley, L , Key, M. M., Groth, D. H., Lainhart, W. S. and Ligo R. M. 1968. Fibrous and content of cosmetic talcum products. Am. Ind. Hyg. Assoc. / 29:j 50-354. Cullity, B. D. 1956. Elements of X-ray diffraction. Reading, Mass.: Addison-Wesley. Daymon, H. 1946. Latent silicosis and tuberculosis. Am. Rev. Tuberculosis s3:5s4-5s9. mineral CONSUMER TALCUM S AND PO W DERS 283 Deer, W. A., Howie, R. A. and Zussman, J. 1962. Rock-forming minerals, voi. 3, Sheet silicates, pp. 203-374. New York: Wiley. Dreessen, W. C. 1933. Effects of certain silicate dusts in the lungs. /. Indust. Hyg. 15:66-78. Dreessen, W. C. and Dalla Valle, J. M. 1935. The effects of exposure to dust in two Georgia talc mills and mines. Pubi. Health Repts. 50:1405-1415. Fleischer, S. S. and Osborn, E. F. 1957. Studies of the system iron oxide-silica-water at low oxygen partial pressures. Econ. Geoi. 52:923-943. Ford, W. E. 1957. Dana's textbook of mineralogy. New York: Wiley. Graham, J. and Graham, R. 1967. Ovarian cancer and asbestos. Environ. Res. 1:115-128. Grner, ]. W. 1934. The crystal structure of talc and pyrophylllte. Zeit. Krist. 88:412-419. Grner, |. W. 1944. The composition and structure of minnesotaite, a common iron silicate in iron formations. Am. Mineral. 29:363-372. Hendricks, S. B. 1938. On the crystal structure of talc and pyrophyllite. Zeit. Krist. 99:264-274. Hildick-Smith, G. 1976. Talc: Review of epidemiologic studies. Proc. Br. Occup. Health Sac.. Edinburgh, Sept. 1975. In press. Hobbs, A. A. 1950. A type of pneumoconiosis. Am. ]. Roentgenol. Radio!. Therap. 58:488-497. Hogue, W. L. and Mallette, F. S. 1949. A study of workers exposed to talc and other dusting compounds in the rubber industry. /. Indust. Hyg. Toxicol. 31:359-364. Holt, P. F., Mills, J. and Young, D. K. 1965. Experimental asbestosis with four types of fibers: Importance of small particles. Ann. N.Y. Acad. Sci. 132:87-98. Hurlbut, C. S., Jr. and Williams, O. R. 1935. The mineralogy of asbestos dust. /. Indust. Hyg. 17:289-293. Kivlluoto, R. 1960. Pleural calcification as a roentgenologic sign of non-occupatlonal endemic anthophyllite asbestosis: Acta Rad. Scand. 194:1-67. Kleinfeld, M. and Messile, J. 1960. Problem areas in pneumoconiosis. Arch. Environ. Health 5:428-437. Kleinfeld, M., Messite, J., Kooyman, O. and Zaki, M. H. 1967. Mortality among talc miners and millers in New York State. Arch. Environ. Health 14:663-667. Kleinfeld, M., Messite, J. and Langer, A. M. 1973. A study of workers exposed to asbestlform minerals In commercial talc manufacture. Environ. Res. 6:132-143. Klug, H. P. and Alexander, L. E. 1954. X-ray diffraction procedures. New York: Wiley. Langer, A. M. and Pooley, F. D. 1973. Identification of single asbestos fibers in human tissues. In Proceedings on the biological effects o f asbestos, ed. Bogovsky et al., pp. 119-125. Lyon: IARC. Langer, A. M., et al. 1973. Identification of asbestos in human tissues. J. Occup. Med. 15(3) : 287-295. Liebling, R. S. and Langer, A. M. 1972. Optical properties of fibrous bruche from Asbestos, Quebec. Am. Mineral. 57:857-864. McLaughlin, A., Rogers, E. and Dunham, K. C. 1949. Talc pneumoconiosis. Br. /. Indust. Med. 6:184-194. Merewether, E. R. A. 1930. The occurrence of pulmonary fibrosis and other pulmonary affections in asbestos workers. /. ind. Hyg. 12:198-222, 239-257. Meurman, L. O. 1968. Pleural fibrocaiclflc plaques and asbestos exposure. Environ. Res. 2:30-46. Meurman, L. O., Klviluoto, R. and Hakama, M. 1974. Mortality and morbidity among working populations o f anthophyllite asbestos miners In Finland. Br. j. Indust. Med. 31:105-112. Millman, N. 1974. Pneumoconiosis due to talc in the cosmetic industry. Occup. Med. 4:391-394. National Research Council. 1975. Nicket. Washington, D.C.: National Academy of Sciences. Moro, L. 1946. On the history of asbestosis. Acta Pathol. Microbiol. Scand. 23:53-59. Parmeggiani, L. 1948. Le pneumoconiosi dei minatori e dei mugnai del talco nel Pinerolese. Rass. Med. Ind. 17:16-17. Porro, F. W. and Levine, N. M. 1946. Pathology of talc pneumoconiosis with report of an autopsy. North. ,V. Y. State Med. / 3:23-25. 284 A. N. ROHL ET A L. Porro, F. VV., Patton, J. R. and Hobbs, A. A. 1942. Pneumoconiosis in the talc industry, ,4m. /. Roentgenol. 4 7 :5 0 7 - 5 2 4 . . Pott, F. and Friedrichs, K. H. 1972. Tumoren der Ratte nach i . D . Injektion faserformiger Staube. Naturwissenschaften 59:318. Pott, F., Huth, F. and Friedrichs, K. H. 1974. Tumorigenic effects of fibrous dust in experimental animals. Environ. Health Persp. 9:313-315. Ravner, J. H. and Brown, G. 1966. Triclinic form of talc. Nature 21 2.1 o5a-1 o53. Reichman, V. 1944. fiber Talkumstaublunge. Arch. Gewerbepachol. Gewerbehyg. 12:31 9-322. Robock, K. and Klosterkotter, W. 1976. The biological effect of dusts o f asbestos and asbestos cement products. Proc. Br. Occup. Health Soc., Edinburgh, Sept. 19 75. In press. Rohl, A. N. and Linger, A. M. 1974. Identification and quantitation of asbestos in talc. Environ. Health Persp. 9:95-109. Ross, M., Smith, W. L. and Ashton, W. H. 1968. Triclinic talc and associated amphiboles from Gouverneur Mining District, New York. Aim. Mineral. 53:751-769. Rubino, G. F., Scansetti, G., Piolatto, G. and Romano, C. A. 1976. Mortality study of talc miners and millers./. Occup. Med. 18:1 86-193. Schepers, G. W. H. 1965. Discussion. Epidemiology of mesothelial tumors in the London area. Ann. N.Y. Acad. Sci. 132:579-602. Schulz, R. Z. and Williams, C. R. 1942. Commercial talc, animal and mineral studies. /. Ind. Hyg. 24:75-82. Siegal, W., Smith, A. R. and Greenburg, L. 1943. The dust hazard in tremolite talc mining, including roentgenological findings in talc workers. Am. ./. Roentgenol. 4:11-29. Stanley, H. D. and Norwood, R. E. 1973. The detection and icentification of asbestos and asbestiform materials in talc. Unpublished report for Pfizer, Inc. Stanton, M. F. and Wrench, C. 1972. Mechanisms of mesothelioma induction with asbestos and fibrous glass. J. Natl. Cancer Inst. 48:797-821. Stemple, I. S. and Brindley, G. W. 1960. Structural study of talc and talc*tremolite relations. /. Am. Ceramic Soc. 43:34-42. Thompson, C. S. 1974. Discussion of the mineralogy of industrial talcs. U.S. Bur. Mines Circ. 1C-863, 22-44. Timrell, V. and Rendall, R. E. G. 1971. Preparation of the UICC (IA R C ) standard reference samples of asbestos. Powder Technol. 5:279-287. Wagner, |. C., Berry, G .t Cooke, T. |., Hill, R. )., Pooley, F. D. and Skidmore, J. W. 1975. Animal experiments with talc. Proc. Br. Occup. Health Soc., Edinburgh, Sept. 1975. In press. Wegeiius, C. 1947. Changes in the lungs in 126 cases of asbestosis observed in Finland. Acta Radiol. 28:139-152. Weiss, 8. and Boettner, E. 1967. Commercial talc and talcosis. Arch. Environ. Health 14:304-308. Wells, ). R. 1965. Talc, soapstone and pyrophyllite. In Mineral facts and problems. Washington. D.C.: Government Printing Office. Whittaker, E. J. W. 1968. The crystal chemistry of the amphiboles. Acta Crystal. 13:291-298. Wright, H. D. 1960. Optical study of talc-tremolite relations. /. Am. Ceramic Soc. 43:42-43. Wyers, H. 1949. Asbestos. Postgrad. Med. / 631-638. Yoder, H. S. 1952. The M g O -A I-O ,-SiO .-H , O system and related metamorphic facies. Am. /. Sci., Bowen Mem. Voi. 569-627. Received April 26, 1976 Accepted August 13, 1976