Physicochemical characteristics of Scenedesmus obliquus with different treatments of melamine

Melamine is an azocyclo-containing organic compound, is traditionally used in the chemical and sporadically mixed into animal feeds to boost protein content. Melamine is used as food additives which has a ranther poor biodegradability. The possibility of water resources and soils being contaminated by melamine discharge arouse more and more concern. This study was designed to test the melamine toxicity effects on aquatic ecosystem. Scenedesmus obliquus was exposed to series melamine concentrations (0, 50, 200, 750 mg/L). Five parameters were measured after 7days exposure, which are growth rate, superoxide dismutase (SOD), photosynthetic pigments, free malondialdehyde(MDA) and soluble sugar contents. Melamine concentration of 50, 200mg/L caused a significant increase in growth and photosynthetic pigments contents. SOD activities of S.obliquun were stimulated first and then inhibited with the increasing of melamine concentrations, and reached its peak in 200mg/L, however, in 750mg/L, it is reduced by 43.6%. The contents of MDA and soluble sugar were inhibited significantly under moderate and high concentrations (50, 200, 750 mg/L) of melamine.This study indicates that, SOD was sensitive to melamine exposure and could be used as a potential biomarker for risk assessment of aquatic ecosystem safety. © 2011 IEEE.