A MINERALOGICAL INVESTIGATION OF A HISTORICAL SILICARE CONSUMER TALC PRODUCT: INITIAL ELECTRON MICROSCOPY REVEALS PARTICLES OF CONCERN

There has been increasing interest in the mineralogy and nature of contaminants in talc-based consumer products in recent years. Despite the high level of curiosity in this topic, not all talc-based products have been comprehensively studied in the peer-reviewed literature. The complexities of these substances, and their potential impurities, therefore remains largely unconstrained. Detailed studies of a given historical product can provide insight into the nature of what workers and consumers may have been exposed to during manufacture and use. One product that has no known public data associated with it is the product Silicare. This study reports results from an initial study of Silicare using scanning electron microscopy and transmission electron microscopy techniques. Our initial results indicate that there is evidence of copper, calcium, iron, and other elements present in the talc materials. SEM data show ambiguous fibrous material within the sample which is tentatively interpreted as fiberglass contamination. Mineralogical impurities of Fe-oxide and apatite also were observed by SEM. TEM data indicate the presence of talc fibers with morphologies consistent with triclinic symmetry and pseudo hexagonal electron diffraction patterns along the stacking direction. An example of a deformed, complex, elongated mineral particle (fiber) was observed in TEM that may be consistent with tremolite. The fiber materials observed would be countable based on the IWGACP December 2021 White Paper. Lamellar aggregates of Ca and Si-rich particles occur. Although preliminary, our results indicate that a diversity of minerals and metals in this example of the Silicare product exist. These initial results open up questions regarding (1) the nature of the observed elongated mineral particles; (2) other mineralogical impurities; and (3) strictly synthetic or anthropogenic impurities in Silicare products. Results indicate that more extensive mineralogical and geochemical characterization of this and other consumer talc products is warranted.