Global water scarcity, intensified by population growth, economic development, and climate change, presents a significant challenge, with the cosmetics industry contributing heavily to water demand. Simultaneously, the cork industry generates substantial amounts of cork boiling wastewater (CBW), an acidic effluent with environmental hazards. This study explored CBW’s potential for cosmetic application, focusing on safety, physicochemical properties, and suitability for incorporation in cosmetic formulations. Three CBW samples (A, B and C) were analyzed for pH, conductivity, turbidity, density, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, and total phenolic content. CBW A displayed suitable physicochemical properties and potential antioxidant activity and was selected for further investigation. Human keratinocyte viability was assessed using CBW A before and after adsorption treatment with silica (TCBW A) to reduce cytotoxicity. CBW A was more toxic to human keratinocytes compared to control water, but treatment improved cell viability. This treatment had minimal impact on physicochemical parameters, aside from reducing phenolic content. Metal concentrations in TCBW A remained within cosmetic safety limits. TCBW A was incorporated into an oil-in-water (O/W) cream, which was further evaluated for pH, droplet size, rheological behavior, textural properties, and stability. The resulting cream was homogeneous, woody-scented, with uniform droplet size and stable after centrifugation. TCBW A incorporation provided suitable rheological behavior and formulation stability after 90 days of storage at 25 °C. These findings indicate that TCBW A has low cytotoxicity, suitable physicochemical properties, and provides stable cosmetic formulations, highlighting its potential as a sustainable ingredient for the cosmetic industry.
Mota et al. (2026) studied this question.