PHYSIOLOGICAL AND CELLULAR RESPONSES OF A SYNTHETIC PRESERVATIVE IN PERSONAL CARE FORMULATIONS ON AQUATIC ORGANISMS

Quaternium-15 (QT-15), widely utilized as a preservative in various personal care products, including shampoos, soaps, shaving items, and cosmetics, has raised environmental concerns as its presence in aquatic ecosystems stems from routine consumer use. With the COVID-19 pandemic, the presence of quaternary ammonium compounds (QACs), in sanitizing and disinfecting products has increased exponentially. Additionally, quaternium-15 has been found to be resistant to degradation, resulting in its persistence in the environment for several years following its release. This persistence raises concerns about the long-term effects on aquatic ecosystems. To detect the potential impact of QT-15 on aquatic communities, bivalves such as Mytilus galloprovincialis are particularly suitable bioindicators. For this reason, this study aimed to explore the physiological and cellular responses of the digestive gland and gill cells of M. galloprovincialis following exposure to QT- 15. The specimens were divided into three experimental groups (CTR: control; E1: 0.5 mg L–1; E2: 1 mg L–1). Each group comprised 49 animals housed in duplicate aquariums, totaling 294 mussels. The concentrations of QT-15 were chosen based on previous studies1,2 and on the concentrations of QACs3. The animals were maintained at constant temperature, salinity, and pH. Fourteen molluscs, randomly sampled from each experimental condition at 7 and 14 days post-exposure to QT-15, were utilized to assess cellular vitality, the regulatory capacity of digestive gland cells in adjusting their volume, and the expression of genes associated with oxidative stress. Results unveiled a notable decline in both the vitality and volume- regulating ability of digestive gland cells when subjected to a hypotonic solution, suggesting a potential link between exposure and compromised cellular function. The altered expression of genes related to oxidative stress, including SOD, Cat, Hsp70, and CYP4Y1, provided molecular insights into cellular responses to the impact of QT-15. In the gills, similar changes in gene expression were observed. These data provide valuable information for understanding the possible environmental impact of QT-15 exposure and highlight the urgency in identifying green and more sustainable compounds that can serve as alternatives in personal care formulations.