Frogs provide a very sensitive biological sensor of dangerous chemicals because of the drastic morphological changes that happen during the transition between tadpole and frog life stages. Endocrine-disrupting chemicals are common chemicals released in municipal wastewater that can have adverse effects at very low concentrations. These effects are often manifested first at the molecular level and by identifying them it will be possible to use frogs as “canaries in the coal mine” in monitoring the biological effects of chemicals. The wild bullfrog was studied with a view to developing methodologies and tools that can be applied to other species. To this end, FrogSCOPE created a new opportunity with the Canadian Municipal Water Management Research Consortium to develop an assay for assessing which type of secondary sewage treatment is most effective at removing biological activity from personal care products and pharmaceuticals in treatment plant effluents.