Toxicological Safety, Antimicrobial Efficacy, and Sensory Evaluation of River Sand-Derived Mica From Bangladesh: A Comprehensive Assessment for Cosmetic Applications.

BACKGROUND

Mica is widely applied in cosmetics, construction, automotive, electronics, defense, and medical industries, particularly important in cosmetics as an ingredient in foundations, eyeshadows, lipsticks, and nail polishes for its pearlescent and shimmering effects.

AIMS

To evaluate the suitability of mica minerals from Bangladeshi river sands for cosmetic applications by investigating their chemical composition, heavy metal content, potential for skin irritation, and antimicrobial activity.

METHODS

The chemical composition, crystallographic structure, and heavy metal content of mica samples were analyzed using X-ray fluorescence, X-ray diffraction, and Atomic Absorption Spectroscopy. Non-carcinogenic and carcinogenic risks were evaluated using USEPA models (ADD, HQ, HI, LADD, ILTCR). Sensory evaluation was performed by 10 trained panelists, while primary skin irritation was tested on albino rabbits. Antimicrobial activity against bacterial and fungal strains was assessed using agar well diffusion and broth microdilution assays.

RESULTS

Muscovite contained high AlO (30.46%) and SiO (49.29%), whereas biotite and phlogopite were enriched in FeO (43%) and MgO, supporting shimmer, color, and UV-protective properties. XRD confirmed high crystallinity and purity. Heavy metals were within safe dermal and inhalation exposure limits. Sensory evaluation showed a silky texture, strong adhesion, and a luminous finish. All samples were non-irritant (PII = 0.00). Biotite and phlogopite exhibited moderate antibacterial activity against Staphylococcus aureus, Salmonella typhi, and Bacillus megaterium, but no antifungal effects.

CONCLUSIONS

Muscovite, biotite, and phlogopite mica exhibit low heavy metal content, non-irritant and non-carcinogenic behavior, moderate antibacterial activity, and favorable sensory properties, highlighting their potential as safe, effective, and multifunctional ingredients for cosmetic applications.