Effect of temperature on biodegradability of surfactants in aquatic microcosm system

Microcosm systems consisting of producer, decomposer and predator were employed to assess the effect of surfactants (LAS and soap) on an aquatic ecosystem at various temperatures. At all test temperatures (10, 20, 25 and 30°C), stable ecosystems were formed with regard to the biomass and species composition in flasks. In the stationary phase, temperature dependency of ATP was observed and the biodegradation rate of the surfactants in microcosm system at low temperature were slower than that at high temperature. Cyclidium glaucoma, Philodina sp. and Aeolosoma hemprichi as predator were more influenced by surfactants at low temperature. No observed effect concentration (NOEC) of LAS was less than 0.5mg·1⁻¹ at 10°C, less than 1.5mg·1⁻¹ at 20, 25°C and less than 2.5mg·1⁻¹ at 30°C. NOEC of soap was less than 10mg·1⁻¹ at 10°C, less than 30mg·1⁻¹ at 20, 25°C. It was found that biodegradability of surfactants differed with temperature, which changed the effects of surfactants on microorganisms.