Plastic pollution is present in every corner of the planet and is routinely ingested by countless species. While there has been increasing public attention toward plastic pollution, little attention has focused on the unseen “dark matter” of the plastics problem: the thousands of chemical additives incorporated into plastic. Despite the prevalence of these additives, their synergistic and cumulative impacts across biological scales are poorly understood. The durability, persistence, and complexity of plastic additives in our ecosystems make plastic additive pollution an open-ended and intractable “wicked” problem for global security. Aligned with societally important goals of protecting the environment and promoting environmental sustainability, this Growing Convergence Research (GCR) project will illuminate the dark matter of plastic additive waste and alleviate the impacts of this waste through a Strategic Initiative to Mitigate Plastic Additive Pollution. This project will bring together a convergent team of experts in molecular and cell biology, environmental toxicology, community ecology, high-throughput chemical screens, environmental chemistry, materials science, plastic policy, environmental law, science education, and community engagement. <br/><br/>This project comprises two phases. Phase I will focus on determining the impacts of plastic additives across biological scales through the following activities: 1) characterization of the impacts of plastic additives on cells, 2) organisms, and 3) ecological communities, 4) an assessment of the regulatory landscape of plastic additives, and 5) community level ground-truthing to assess product use and potential additive exposures in communities. Phase II will integrate knowledge gained in Phase I to develop and pilot mitigation strategies to: 6) prioritize additive combinations in need of the most urgent mitigation, 7) model novel regulatory interventions; and 8) test policies and create action plans for convergence on plastic additives. The broader impacts include deep engagement with external stakeholders across sectors to implement innovations at the local scale to reduce plastic pollution. The project will also empower students underrepresented in STEM and other to take action against environmental pollution in vulnerable communities.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.