Aquatic Toxicity of Hydroquinone and Catechol Following Metal Oxide Treatment to Ceriodaphnia dubia and Pimephales promelas

Abstract

Abstract Metal oxides comprise a large group of chemicals used in water treatment to adsorb organic pollutants. The effects of titanium dioxide (TiO2) and iron (III) oxide (Fe2O3) to reduce the chronic toxicity of (phenolic) C6H6(OH)2 isomers, namely hydroquinone (HQ) and catechol (CAT) to Ceriodaphnia dubia and Pimephales promelas were investigated. The toxic endpoints following metal oxide treatment were compared to endpoints of untreated CAT and HQ. Chronic toxicity testing to HQ resulted in greater toxicity than CAT for both test organisms; the median lethal concentrations (LC50) for CAT were 3.66 to 12.36 mg.L− 1 for C. dubia and P. promelas, respectively, while LC50s for HQ were 0.07 to 0.05 mg.L− 1, respectively. Despite both treated solutions presented lower toxic endpoints than those in the untreated solutions, Fe2O3 had a better potential to reduce the toxic effects of CAT and HQ than TiO2.