The document discusses uncertainties in modeling human and ecological risks from chemicals, nanomaterials, and microplastics in the environment. Current risk management is reactive, substance-by-substance, and resource intensive. Modeling risks considers sources, emission, fate, exposure, and effects, but faces many uncertainties. For chemicals, better use and spatially explicit emissions data is needed. Fate modeling requires improved degradation data, especially for ionizing compounds. Effect modeling needs more data on mixtures, genomics, and untested substances. For nanomaterials and microplastics, long-term fate and effects are particularly uncertain due to degradation questions and lack of data.