8 - Personal Care Products in the Aquatic Environment: A Case Study on the Effects of Triclosan in Fish

Abstract

Pharmaceuticals and personal care products (PPCPs) are widely used by individuals for health or cosmetic reasons, or by industries such as agrifood and business to promote growth or protect the health of production animals. These chemicals include a huge variety of therapeutic drugs for humans, veterinary drugs, fragrances, and cosmetics. Among these and the focus of this chapter are chemicals used for preventing the growth of bacteria and other pathogens. Here, as a case study, we consider triclosan (TCS), a chlorinated phenoxy phenol that is a potent antibacterial and antifungal chemical. TCS is used in many personal care products, including shampoos, toothpaste, deodorants, and liquid soaps, in textiles used for sport clothing, as well as in plastic and polymers for medical uses. It is considered relatively safe to humans, although there are emerging concerns about the development of bacterial resistance and heightened sensitivity to allergens. In this chapter we consider its no-target effects on fishes. Similar to other personal care products, TCS enters municipal waste and, although the majority of the TCS is removed from the wastewater treatment plant (WWTP) effluents, some TCS enters surface waters. TCS has the potential to bioaccumulate in aquatic organisms and exert adverse physiological effects. Algae are extremely sensitive to TCS, with growth inhibition occurring at concentrations measured in surface waters. Fish are similarly negatively affected by TCS, with notable reproductive and developmental effects, including lower hatchability of eggs, delayed time to hatching, and reduction in swim performance being reported. Some of the TCS effects occur through disruption of the thyroid axis. Even though the effects in fish generally occur at TCS concentrations higher than those measured in the environment, the concern is that the potential for increasing environmental concentrations of TCS is significant because it is still used in many products worldwide. Indeed, the use of TCS is being reevaluated in several OECD countries because of growing evidence concerning its potential to exert adverse effects on fish and other aquatic organisms.