TOXICITY EVALUATION OF TWO TYPICAL SURFACTANTS TO DUNALIELLA BARDAWIL, AN ENVIRONMENTALLY TOLERANT ALGA

Sodium dodecyl benzene sulfonate (SDBS) and cetyl trimethyl ammonium chloride (CTAC) are two kinds of surfactants widely applied in various industries. The tremendous direct discharge of these surfactants into natural waters has posed a significant threat to ecosystems. Dunaliella bardawil was employed in the present research to test the toxic effects of SDBS, CTAC, and their mixture on cell growth, cellular morphology, beta-carotene accumulation, and enzymatic activities of superoxide dismutase (SOD) and catalase (CAT). The results showed that SDBS at 200, 550, 900, 1,350, 1,800, and 2,400?mg/L and CTAC at 0.4, 0.7, 1.0, 1.3, 2.8, and 3.5?mg/L inhibited algal growth and beta-carotene accumulation, both of which declined and then increased. In particular, CTAC (median inhibitory concentration at 10 days [IC50]10?d?=?2.8 +/-?1.49?mg/L) was more hazardous than SDBS (IC5010?d?=?2,044 +/- 637.3?mg/L). The additive index (AI) calculated from carotene content data was (-4.10, -1.67)