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 aqu atic ecosystem at various temperatures. At all test temperatures (10, 20, 25 and 30 degrees C), stable ecosystems were formed with regard to the biomass and species composition in flasks. In the stationary phas e, temperature dependency of ATP was observed and the biodegradation r ate of the surfactants in microcosm system at low temperature were slo wer than that at high temperature. Cyclidium glaucoma, Philodina sp. a nd Aeolosoma hemprichi as predator were more influenced by surfactants at low temperature. No observed effect concentration (NOEC) of LAS wa s less than 0.5 mg . l(-1) at 10 degrees C, less than 1.5 mg . l(-1) a t 20, 25 degrees C and less than 2.5 mg . l(-1) at 30 degrees C. NOEC of soap was less than 10 mg . l(-1) at 10 degrees C, less than 30 mg . l(-1) at 20, 25 degrees C. It was found that biodegradability of surf actants differed with temperature, which changed the effects of surfac tants on microorganisms. Copyright (C) 1996 IAWQ.