Di-(2-ethylhexyl) phthalate induced the growth inhibition and oxidative damage in the microalga Chlorella vulgaris

Abstract

di-2-ethylhexyl phthalate (DEHP) poses a great threat to aquatic ecosystems, with known hazards to aquatic species. The ecotoxicological mechanism of DEHP in ocean microalgae is not yet known. In this study, we investigated growth inhibition, oxidative damage and antioxidant enzyme activities in Chlorella vulgaris under DEHP treatment. After 5-d exposure to DEHP ranging from 2 to 10 mg/L, the growth of C. vulgaris was significantly inhibited. The 96-h median effective concentration values (96h-EC50) of DEHP for C. vulgaris were 6.02 mg/L. This growth inhibition was associated with DEHP-induced oxidative stress, as evidenced by elevated levels of intracellular malondialdehyde (MDA) and hydrogen peroxide. The results showed that DEHP reduced superoxide dismutase and glutathione peroxidise activities, increased hydrogen peroxide level and MDA content in a concentration-dependent way. These results indicated that DEHP could have biochemical and physiological toxic effects in C. vulgaris. These findings will help to understand the toxicity mechanisms of DEHP and the environmental risk assessment of primary producers of aquatic ecosystems.