Effect of the microbial population size on the degradation of linear alkylbenzene sulfonate in lake water (Dong Hu = East Lake, Wuhan, Hubei, P.R. China)

Abstract

To study the correlation between the degradation rate of linear alkylbenzene sulfonate (LAS), a commercially marketed detergent, and the initial bacterial population size in lake water (Dong Hu, Wuhan, P.R. China), 1.5 mg·1 −1 LAS was added to lake water samples collected from various locations of Dong Hu with different concentrations of LAS and different microbial levels. The exposure time was 72 hours and samples were taken at time zero, then at 12, 24, 36, 48 und 72 hr. Each sample was submitted to the MBAS (methylene blue active substances) analytical procedure for the determination of remaining anionic substances. Microbial density was estimated by dilution plate method for each test medium at time zero and 72 hr. The results indicate that the LAS degradation rate was affected by the size of microbial population of the test medium.