The Acute Toxicity of Dispersant and Chemically Dispersed Oil on the Argopecten irradians

Abstract:

Chemical dispersant has rapidly gained popularity in controlling unwanted oil spill in the aquatic environment, however, it exerts adverse effects on the aquatic organisms. The acute toxicity of chemical dispersant on fish, algae and zooplanktons has been widely investigated in previous studies. In the contrast, the acute toxic effects on shellfish remains unclear. In this study, we examined the acute toxic effects of chemical dispersant, dispersed 0 diesel oil (WAF) and chemically dispersed 0 diesel (CEWAF) on A. irradians. The test was performed within 96h, and the concentrations of chemical dispersant, WAF and CEWAF ranged from 0.50-3.00, 5.88-58.80 and 3.54-20.00 mg/L respectively. The LC50 values (within 95% confidence intervals) of dispersant in A. irradians were 1905, 1293, 1015 and 846 mg/L in the time courses of 24 h, 48 h, 72 h and 96 h respectively. The LC50 values of WAF were 36.57, 23.10, 14.99 and 11.31 mg/L corresponding to different time courses, and the values of CEWAF were 12.71, 8.51, 6.56 and 5.42mg/L respectively. As the time course increased from 24 h to 96 h, the median lethal concentrations (LC50) of chemical dispersant, WAF and CEWAF were decreased accordingly. The median lethal concentration and time course appeared to be highly correlated. The functions of LC50 (y) of dispersant, WAF and CEWAF against time (x) were y=12242x-0.583, y=564.37x-0.848, and y=89.987x-0.613 respectively. For the same exposure time, the order of the median lethal concentrations was dispersant > WAF > CEWAF, suggesting that the acute toxicity of CEWAF on A. irradians was higher than dispersant and WAF.