Acute toxicity of benzotriazole ultraviolet stabilizers on freshwater crustacean (Daphnia pulex)

Benzotriazole ultraviolet stabilizers (BUVSs) enter aquatic environments either directly, via wash-off from skin and clothes during water recreational activities, or indirectly, via discharges of sewage and swimming pool waters. Their potentially toxic effects on biota, particularly aquatic organisms, are of considerable concern. However, not much information on their toxicity to aquatic organisms is available. In the present study, we investigated the acute toxicity of selected BUVSs on a freshwater crustacean (Daphnia pulex) for the first time. The 24 and 48-hr median lethal concentration (LC50) values of UV-571 for D. pulex were estimated to be 6.35 (5.08-8.39) and 2.59 (2.04-3.38) mg/l, respectively. No acute toxicity effects were observed up to 10 mg/l for other BUVSs such as UV-9, -320, -326, -327, -328, -329, and -360. Although acute toxicities of targeted BUVSs were not high, further long-term studies are required to fully assess the effects on growth and reproduction by these compounds on aquatic biota because of their bioaccumulative characteristics.