Acute ecotoxicity tests with passive dosing method. The ecotoxicity test was conducted for C14-, C16-and C18-BACs using the passive dosing approach because these long alkyl chain BACs were expected to be more susceptible to chemical loss processes such as sorption onto the glass vessels and formation of micelles in exposure solution than shorter analogs. 8, The loaded PES membranes were prepared following the procedure described in the Loading experiment section. Each test beaker received a loaded PES membrane and 5 daphnids in 50 mL (C14-BAC) or 30 mL (C16-and C18-BACs) of dechlorinated water.