*2.2. Citizen Science Demonstration of EDC Footprint Calculator*

In June 2021, we recruited 58 citizen scientists to take part in a project that sought to establish links between EDCs in household products they use and the presence of these EDCs in surface water samples from various locations across the Pennsylvania portion of the Susquehanna River Basin, which is the largest tributary to the Chesapeake Bay watershed in the northeastern United States. The citizen scientists were volunteers and filled out the EDC footprint calculator as part of their participation in the project. Results of the footprint tool were distributed to participants in a final report that included their household's footprint, as well as a summary of the results for the other 57 participants to provide context regarding their own household's footprint. After final reports were distributed, 39 citizen scientists responded to a post-study survey, which included some general demographic questions. In this research, we used the results of the demographic questions (Table 2) to interpret the results of the EDC footprint tool based on household size.

**Table 2.** Demographic information for each of the 39 citizen scientists located across the Susquehanna River basin in the northeastern United States who volunteered to calculate and share their endocrinedisrupting compound (EDC) footprint.

