The emergence of microplastics: charting the path from research to regulations

Despite decades of research detailing widespread contamination and potential risks of microplastics (synthetic particles <5 mm) to humans and ecosystems by the scientific community, government agencies have made little progress to address the emerging contaminant class. Research on microplastics has increased exponentially in recent years, however translation of studies and data into knowledge that's useful for management requires clear communication between the scientific and management communities. Legislative mandates to address microplastics in drinking water and aquatic ecosystems in California prompted rapid development of fundamental tools and methods for identifying and assessing risks, including a legal definition, analytical monitoring methods, and risk assessment frameworks. While this scientific progress provides a baseline foundation for developing regulations for microplastics in California and other jurisdictions, additional research is needed to reduce uncertainties and overcome logistical barriers that are preventing the full emergence of microplastics as a regulated contaminant suite. This paper provides critical insights from both scientific and regulatory perspectives regarding recent advances in the field and recommends a path forward to overcome barriers.