Better Metrics for Sustainable by Design: Toward an in Silico Green Toxicology for Green(er) Chemistry

Sustainable, green chemistry cannot be successful without a clear way of measuring what makes a chemical greener. One central tenet of green chemistry is the avoidance of toxicity and improvement of sustainability, yet the metrics to design a less toxic alternative or avoid problematic lifecycle issues are woefully lacking. Toxicologists have limited tools available to provide R&D chemists the necessary guidance in designing less toxic chemicals. Current metrics for the most part cannot assay toxicity in a time frame that is useful for the business cycle. The methodologies typically used for toxicology end points also provide little information that is useful for chemists to improve their sustainable design. Here, we discuss both the problems with existing metrics for assessing toxicity and sustainability, and the steps necessary for better hazard and risk assessment via big data and machine learning for more sophisticated metrics based on in vitro and in silico testing.