Most contaminant studies focus on the effects of a single contaminant effect on organisms; however, most contaminants are not found alone within the environment. For example, 27 different pharmaceuticals and personal care products (PPCPs) were found in significant concentrations near a wastewater treatment facility outfall in Milwaukee Harbor by Blair et al. (2013). Wastewater treatment facilities do not have the ability to remove all PPCPs from the wastewater and so they are released into aquatic ecosystems with the treated effluent. The goal of this study is to determine the effects of two PPCPs, ibuprofen (a non-steroidal anti-inflammatory drug) and triclocarban (an antimicrobial), singly and in combination on the water flea, Ceriodaphnia dubia. Based on results of single contaminant acute toxicity tests, mixture toxicity tests will be run using relative proportions of their EC50 values (effective concentrations for 50% of the population) for the two contaminants. In each test, there will be six treatments with the dilution water being moderately hard reconstituted water. There will be four replicate beakers per treatment, and each beaker will contain five Ceriodaphnia dubia water fleas neonates. Solutions will be renewed and survival recorded daily and the tests will run for 48 hours. Results gathered thus far indicate; ibuprofen and triclocarban are acutely toxic to Ceriodaphnia dubia at concentrations greater than 100 mg/L (ppm) and 5 µg/L (ppb), respectively. Therefore, I predict that the two PPCPs being tested will have an additive effect on the Ceriodaphnia.
