Salinization is an ongoing global threat exacerbated by population growth and climate change. Rising temperatures that increase evaporation rates and road salt use (due to milder winters), as well as increasing urbanization and associated wastewaters, agricultural practices and resource extraction activities, contribute to salinization in freshwaters, estuaries and soils. Osmotic stress or other impacts on ion regulation due to increases in ion concentrations can be a significant source of toxicity and can have adverse impacts on the toxicity of other chemicals within contaminant mixtures. There has been considerable advancement of major ion toxicity research in the last decade from the broader SETAC community regarding the direct risk to aquatic organism health and the potential for impairment on the structure and function of freshwater, estuarine and soil ecosystems. To address the challenges surrounding ecosystem salinization, three speakers from different sectors will provide an overview of the sources, ecosystem interactions, toxicity, regulatory approaches and management of salt and saline waters with a discussion on next steps towards mitigation.