158 D8. Minerals, Energy, Microbes, and Organics: Impacts on the Environment, Society and Health

Tuesday, 24 September 2019
8:00 AM - 12:00 PM
Room 132ABC, North Building

A PRELIMINARY TRANSMISSION ELECTRON MICROSCOPY ASSESSMENT OF TALC FROM SMALL BOTTLES OF JOHNSON’S BABY POWDER SHOWS VARIATION IN MINERALOGY AND THE PRESENCE OF FIBROUS TALC

Paper number: 158-15
Program: Technical Sessions
Time: 11:20 AM – 11:35 AM

Authors

Abstract

Baby powder is exposed to human skin, the respiratory system, and the reproductive system. There is concern over the nature and variability of mineral content in baby powder, yet there is little detailed transmission electron microscopy (TEM) investigations in the peer-review literature regarding this consumer mineral product. As a preliminary assessment, TEM analysis was conducted on small bottles of Johnson’s baby powder that was purchased from a major retail store in Hamilton, Ohio. Talc particles in sample material investigated thus far vary significantly in morphology and dominantly are euhedral to anhedral platy particles. Electron diffraction of platy particles suggest approximately 90% are reasonably highly crystalline with single nets or nets with minor offsets for diffraction taken along [00l] and approximately 10% of talc particles have significant rotational disorder. Numerous examples of talc particles < 10 micrometers in diameter occur. Examples of fibrous talc occur at a level of approximately 0.1 to 2.0 percent and the occurrence of these particles vary over the grid squares. Fibrous talc is easily distinguished from platy talc particles resting on (hk0) faces by electron diffraction. For fibrous talc, diffraction for [00l] shows a pseudo hexagonal net indicative of the hexagonal closest packing of the talc structure whereas diffraction along (hk0) shows other streaked reflections indicative of stacking disorder. Talc particles have a chemical composition dominated by Mg, Si, and O and consistently has minor amounts of Ca, Fe and Al. Some fibrous talc has minor amounts of K. Cr peaks that are close to the edge of the detection limit are observed in some but not all spectra of talc particles. Presumably natural mineral impurities occur and include minor amounts of particles with elements of environmental health concern such as oxide aggregates with detectable lead and dolomite with detectable nickel. This preliminary initial assessment suggests more extensive TEM work is warranted.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-338386

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