Cumulative Risk Assessment Workshop: Addressing Combined Environmental Stressors
Cumulative risk assessment (CRA) addresses the impacts of multiple chemical and nonchemical stressors on communities, resulting from complex exposures for populations with a variety of vulnerabilities. These efforts focus on real world exposure scenarios and applications that range from environmental justice and community sustainability to population health promotion and protection. Nonchemical stressors include biological and physical agents (e.g., microbes and noise) as well as socioeconomic stressors and psychosocial conditions (e.g., associated with natural disasters). Public concerns that can initiate CRAs include (1) elevated environmental measurements or biomonitoring data; (2) multiple sources of pollutants or stressors; and (3) changes in disease rates or patterns (e.g., leukemia cluster) or ecological effects (e.g., loss of wildlife diversity). This workshop focuses on human health and begins with an overview of three CRA elements: analysis, characterization, and quantification (as feasible) of the combined risks from multiple stressors. Teaching methods include lectures and hands-on exercises. Presentations highlight basic concepts, methods, and resources for conducting a population-based CRA. A central theme is integrating exposure and dose-response information with population characteristics during planning and scoping based on initiating factors. Vulnerability factors are also addressed including socioeconomic status, lifestyle and behavioral factors (e.g. diet/nutritional status), psychosocial stress, as well as susceptibility due to immutable factors (e.g. race, age, genetics). Methods for estimating human health risks are discussed and applied, including epidemiologic approaches and assessing the joint toxicity of chemical mixtures. In the exercises, participants develop chemical and non-chemical stressor groups using exposure and toxicity factors, link them with population vulnerability factors and conduct a cumulative risk characterization.