Triclosan is toxic to aquatic bacteria at levels found in the environment. It is highly toxic to various types of algae and has the potential to affect the structure of algal communities, particularly immediately downstream of effluents from wastewater treatment facilities that treat household wastewaters. Triclosan has been observed in multiple organisms, including algae, aquatic blackworms, fish, and dolphins. It has also been found in land animals including earthworms and species higher up the food chain. In toxicity experiments with "Vibrio fischeri" marine bacterium, an EC50 value of TCS equal to 0.22 mg/L has been determined. Few data is available for the long-term toxicity of TCS to algae, daphnids and fish, while enough data is available for its acute toxicity on these groups of organisms.