A simple hydrophobicity-based approach to predict the toxicity of unknown organic micropollutant mixtures in marine water

In this study, we propose a simple hydrophobicity-based approach to predict the toxicity of mixtures of marine organic micropollutants. Fifty mixtures were chosen, comprising individual chemicals randomly chosen from three halogenated benzenes, three phenols, two petroleum hydrocarbons, three polychlorinated biphenyls (PCBs), four organochlorine pesticides (OCPs) and two herbicides, with the intention of simulating the mixtures of organic micropollutants that may exist in some marine waters. The hydrophobicity of the mixtures was quantified by measuring the C(18)-Empore(TM) disk/water partition coefficients (K(MD)). A K(MD)-based approach was proposed to describe their toxicity to Photobacterium phosphoreum, and the application of this approach to another 10 related mixtures proved its predictive capability, as indicated by the consistency between the predicted and observed toxicities (r(2)=0.905, SE=0.101, and F=76.325 at P<0.001). This predictive capability convinces us that the K(MD)-based approach provides a general approach to predicting the toxicity of mixtures of organic micropollutants in marine water.