Methods for Evaluating the Combined Effects of Chemical and Nonchemical Exposures for Cumulative Environmental Health Risk Assessment

Abstract

Cumulative risk assessment (CRA) has been proposed as a means of evaluating possible additive and synergistic effects of multiple chemical, physical and social stressors on human health, with the goal of informing policy and decision-making, and protecting public health. Routine application of CRA to environmental regulatory and policy decision making, however, has been limited due to a perceived lack of appropriate quantitative approaches for assessing combined effects of chemical and nonchemical exposures. Seven research projects, which represented a variety of disciplines, including population health science, laboratory science, social sciences, geography, statistics and mathematics, were funded by the US Environmental Protection Agency (EPA) to help address this knowledge gap. We synthesize key insights from these unique studies to determine the implications for CRA practice and priorities for further research. Our analyses of these seven projects demonstrate that the necessary analytical methods to support CRA are available but are ultimately context-dependent. These projects collectively provided advancements for CRA in the areas of community engagement, characterization of exposures to nonchemical stressors, and assessment of health effects associated with joint exposures to chemical and psychosocial stressors.

Defining and Intervening on Cumulative Environmental Neurodevelopmental Risks: Introducing a Complex Systems Approach

“…2012 ). Yet, there has been no progress in this regard, with cited reasons including data deficiencies, inherent analytical complexities, lack of mechanistic understanding regarding stressor interactions, and lack of sufficient analytical tools ( Sexton 2015 ; Payne-Sturges et al. 2018 ).…”

“…2011 ). Calls for federal and state environmental agencies to consider such cumulative risks in regulatory and policy decisions have been made by community advocates, stakeholders, and independent advisory bodies since the 1980s ( NRC 1993 ; National Environmental Justice Advisory Council 2004 ; NRC 2008 , 2009 ; Browner and Hansen 1997 ; U.S. EPA 1986 ), and significant research investments have been made to develop methods to assess the combined effects of multiple chemical and nonchemical exposures ( National Institute of Environmental Health Sciences 2018 ; Payne-Sturges et al. 2018 ; Macdonell et al.…”

“…2016 ; Lewis et al. 2011 ), but rather because of the inability or unwillingness to formulate an approach that is necessarily multidisciplinary and captures the dynamic complexity to inform policy analysis ( Payne-Sturges et al. 2018 ; Knudsen 2017 ; Harrison 2017 ).…”

Participatory Research for Environmental Justice: A Critical Interpretive Synthesis

“…Although research products such as health impact assessments or policy analyses can offer real value, EJ communities may struggle to use these products toward structural change without political power, funding, or lasting institutional partnerships ( Bourcier et al. 2015 ; Payne-Sturges et al. 2018 ; Scammell and Howard 2020 ).…”

“…In some cases included here, a study successfully identified environmental health risks or community priorities but described only hypothetical next steps toward addressing them (e.g., Quach et al 2015). Although research products such as health impact assessments or policy analyses can offer real value, EJ communities may struggle to use these products toward structural change without political power, funding, or lasting institutional partnerships (Bourcier et al 2015;Payne-Sturges et al 2018;Scammell and Howard 2020).…”