Assessment of ibuprofen toxicity and removal potential of Chlorella vulgaris

Abstract

Ibuprofen, a most widely used anti-inflammatory drug, is frequently detectable in surface water, which might negatively affect the ecosystem. The present research investigated acute toxicity of ibuprofen to Chlorella vulgaris, and ibuprofen removal by C. vulgaris was also evaluated via a first order kinetic model. The results showed that ibuprofen in water has certain freshwater ecological risks, and ibuprofen-contaminated water can be effectively treated by C. vulgaris. The growth and the photosynthetic activity of C. vulgaris were decreased with the increase in ibuprofen exposure concentration, while superoxide dismutase and catalase activities were markedly promoted. The dry weight of C. vulgaris exposed to 100 mg/L ibuprofen was determined as 0.238 ± 0.008 g/L, which was 60.82% of the control group (without added ibuprofen in medium). The capacity of C. vulgaris to ibuprofen removal was decreased with the increase in ibuprofen concentration. The removal efficiency reached to 67.25% after 10-day treatment at ibuprofen concentration of 25 mg/L, while that was just 32.77% when the ibuprofen concentration increased to 100 mg/L. The ibuprofen removal by C. vulgaris accorded with the first-order kinetic model, and the removal rate constants of C. vulgaris to different ibuprofen concentrations (25, 50, 75 and 100 mg/L) were determined as 0.115, 0.097, 0.093 and 0.043 d−1, respectively.