Environmental justice communities, those disproportionately affected by pollutants, are simultaneously exposed to multiple environmental stressors and also experience social and cultural factors that may heighten their health risks in comparison to other communities. In addition to being more susceptible to toxic exposures and being exposed to more toxins, such communities may have weakened abilities to combat or rebound from such exposures. Many communities that are overburdened by environmental exposures reject traditional risk assessment approaches that solely consider the effects of single chemicals or mixtures of like chemicals and instead have advocated for the use of place-based approaches and collaborative problem solving models that consider cumulative exposures and impacts. Cumulative risks are the combined risks from aggregate exposures to multiple agents or stressors, including chemical, biological or physical agents and psychosocial stressors. This dissertation adapts three research approaches that each use either publicly available data (“expert” data) or community-generated data about environmental and social factors in Northwest Atlanta’s Proctor Creek Watershed. Through this work, we were able to define cumulative environmental and social impacts experienced by watershed residents and to prioritize geographic areas and environmental challenges for investments in environmental monitoring and further research, community capacity-building, and policy change. A principal finding of the study is that local community knowledge is helpful to fill critical gaps about local conditions and pollution sources than a reliance on expert data alone.