Polyacrylate crosspolymer-11 enhances soil clay dispersibility: An indication for inadvertent environmental impacts from personal care and cosmetic ingredients

Polymer ingredients are commonly found in personal care and cosmetic industry and their "leakages" into the environment have recently been warned as an emerging environmental risk. Daily use of personal care and cosmetic products can inadvertently release large amounts of polymer ingredients into water courses. However, their fate and interaction with other constituents, especially colloids (e.g., clays), have not been fully understood. This study primarily evaluates the colloidal dynamics of soil clays under the presence of polyacrylate crosspolymer-11 (PC11) (a common ingredient of cosmetic and personal care products) with the aim of identifying possible induced changes in the clay-accumulated environments, e.g., soil and sediment. The test-tube experiments were coupled with a particle charge detector to mutually evaluate the colloidal dynamics and surface charge properties of the soil clays. It was revealed that adsorption of PC11 onto the clays shifted clay surface to more negative, thereby intensifying repulsive force and favouring the dispersion state of the soil clays. This implies that various polymer ingredients can act in the same way in stabilizing clay dispersion or even altering the fate of the soil clays. As the growing consumption of personal care and cosmetic products will likely continue, it requires a tighter consideration of the possible impacts of polymer ingredient residues, not limited to dispersion-induced effects, in various clay-accumulated environments such as paddy fields, river mouths or mangroves.