The Effect of the Antibacterial Handsoap Matrix on the Kinetics of Triclosan Dissolution from Sand

Abstract

Triclosan (5-Chloro-2-(2,4-dichlorophenoxy)phenol) is present in many common household products. Most notably, triclosan, is an active ingredient in disinfecting hand soaps, cosmetics, and dental products because of its anti-microbial properties. In addition to triclosan’s anti-bacterial benefits, it is also a suspected endocrine disrupting compound. For this reason, it is the subject of numerous studies related to environmental fate. Due to its prolific use and subsequent detection in wastewater treatment plant effluent, riverine systems, sediments, and estuaries, the mobility and recalcitrance of triclosan within the environment is of great concern and therefore a subject of this research. This study examines the dissolution kinetics of triclosan from amended F-65 Ottawa sand. F-65 Ottawa sand is used for this work as a model river sand. Two sources of triclosan were analyzed, one a high-purity triclosan compound, Irgasan, and the other a triclosan-containing antimicrobial hand soap (Bac-Down). Triclosan kinetic dissolution rates for both systems were quantified using a continuously stirred tank reactor coupled with fiber optic UV absorbance spectroscopy. Finally, concentration dependence of dissolution rates was also determined for the Bac-Down amended sand. The comparison of Irgasan and Bac-Down amended F-65 dissolution experiments found that surfactant additives in Bac-Down increase triclosan’s aqueous solubility and increase dissolution kinetics. Comparison of the varying concentrations of Bac-Down-amended sand indicated a strong correlation of increased aqueous solubility and dissolution kinetic rates with increased mass loading of Bac-Down. This research adds to the current body of research on the adsorption-desorption potential of triclosan in riverine systems and provides data that can be utilized to predict and model triclosan fate and transport.