Identification of potential PBT behavior of personal care products by structural approaches

Several organic ingredients in personal care products (PCPs) became recently compounds of increasing environmental concern, being frequently detected mainly in receiving waters. However, there is limited understanding of how these emerging contaminants may affect wildlife communities, as well as humans. In particular, data on persistence, bioaccumulation and toxicity (PBT) are generally lacking and the environmental behavior of PCPs needs to be further investigated. The determination of all the dangerous properties is a long and difficult task, thus it is very important to have tools to quickly screen and highlight the most hazardous compounds, focusing the experiments only on the prioritized compounds. QSAR models can predict missing data for the unknown activities and properties, necessary to prioritize chemicals, directly from the chemical structure. Using QSAR models, in this work we have studied the potential cumulative PBT behavior of hundreds of PCPs. More than 500 chemicals have been screened for their PBT properties by applying different tools: the Insubria PBT Index, a QSAR model included in the QSARINS software, and the US-EPA PBT Profiler. A priority list of the potentially most hazardous PCPs, identified in agreement by both the modeling tools, is therefore proposed: some sun-screens are among the few PCPs identified as PBTs. This study also shows that the PBT Index could be a valid tool to evaluate immediately from the molecular structure safer and more environmentally sustainable chemicals, a priori from the chemical design in a benign by design approach of Green Chemistry, avoiding unnecessary synthesis and expensive tests.