This page is optimized for a taller screen. Please rotate your device or increase the size of your browser window.

Measuring Environmental Injustice

November 19, 2021

How Can We Assess Cumulative Effects in Vulnerable Communities?

Addressing the disproportionate health and environmental effects experienced by vulnerable minority or low-income communities is a high priority for the Biden Administration. The American Rescue Plan Act of 2021, signed into law on March 11, 2021, allocated $50M to EPA for activities that address overburdened communities experiencing an unequal share of  environmental or public health harms and risks. EPA is already awarding funds to states and communities around the country, and is providing additional funding opportunities for research proposals that examine health-related vulnerabilities to climate change in underserved communities.

This renewed focus on environmental justice means existing research, analytic tools, and regulatory statutes must be reevaluated for their suitability in addressing complex environmental challenges with multiple dimensions. EPA has asked the National Academy of Sciences to provide guidance on research needs for the future, including methods for assessing cumulative effects in vulnerable populations. These methods must address a multitude of potential stressors, including pollution due to climate change that exacerbates health issues, or place-based social stress due to living in proximity to industrial facilities.

Tools EPA Can Use to Characterize Health Effects from Pollution Exposure in Overburdened Communities

Cumulative risk assessment and cumulative impact assessment are two primary tools available to risk managers to support decision-making in environmental justice contexts. They allow EPA to characterize the magnitude of health risks to humans or ecological receptors, but for different purposes and at different scales. 

Cumulative risk assessment is the analysis, characterization, and potential quantification of the combined risks to health and the environment from multiple stressors. These stressors could be chemical mixtures or combinations of chemical and nonchemical stressors such as heat or noise that amplify socioeconomic vulnerability. As with traditional risk assessments for single chemicals, cumulative risk assessments may be conducted to support national regulatory standards for pollutants. 

EPA has the authority to conduct cumulative risk assessments in a few situations, mainly those involving chemical mixtures. For example, under the Food Quality Protection Act, EPA is required to conduct cumulative risk assessments for pesticides with a common mechanism of toxicity and, to date, has conducted these assessments for five pesticide groups, including organophosphates and triazines. EPA has also conducted cumulative risk assessments of chemical mixtures as part of the Superfund risk assessments under the Comprehensive Environmental Response, Compensation and Liability Act, and for disinfection byproducts under the Safe Drinking Water Act.

Additionally, the 2016 Lautenberg Amendment to the Toxic Substances Control Act now requires that EPA conduct chemical assessments that address "unreasonable risk to a potentially exposed or susceptible subpopulation." This could involve assessing aggregate exposures to a single chemical through multiple pathways, such as air, water, and food. It also necessitates consideration of susceptibilities that can influence the risk of an adverse response from exposure to pollutants, which could result from other chemical co-exposures, a particular lifestage, a pre-existing condition, or life stresses such as those resulting from poverty. Cumulative risk assessment could be a key tool in addressing population susceptibilities under TCSA's Lautenberg Amendment.

Applying cumulative risk assessment to quantitatively assess how sociodemographic factors in environmental justice communities affect health risks from pollutant exposures remains challenging. For example, exposome research, which could be key to understanding the totality of environmental exposures, is still evolving. (Exposomics is the study of how all environmental exposures throughout life interact with individual genetics and physiology to impact health, including lifestyle factors, chemical exposures, dietary intakes, and social stress.)

And, while many analytic tools are already available to assess cumulative risks, current regulatory statutes may restrict EPA from fully implementing national standards that incorporate cumulative effects until more scientific evidence becomes available. However, this does not restrict the use of cumulative risk assessment in other contexts including permitting, resource allocation, and establishing priorities for research and analysis.

Cumulative impact assessment is another important tool that can help risk managers qualitatively characterize cumulative health effects in these communities. Cumulative impact assessment (or health impact assessment) is a process that uses multiple methods and data sources, including input from stakeholders, to determine the potential health or environmental impacts of a proposed decision--for example, siting of a waste management facility. Impact assessments are comprehensive, can include data from a cumulative risk assessment, and are geographically focused. This means essential tools like EJSCREEN can be used to find overburdened populations that need attention. Linking quantitative risk estimates with qualitative information, impact assessments can help characterize the magnitude, direction, likelihood, and distribution of cumulative effects when data is lacking on nonchemical stressors or complex chemical mixtures.

Abt Puts Methodologies into Action

Abt Associates has deep experience aiding federal agencies, states, and tribes, and communities in assessing cumulative risks and impacts. We have helped tribal communities characterize cumulative impacts from combined exposures to radionuclide contaminants and climate change stressors so that the health impacts on their community can be understood. We conducted an assessment of the combined effects of childhood exposures to metal mixtures in food on subsequent lifetime IQ loss. Abt developed the Risk-Screening Environmental Indicators (RSEI) tool for EPA, which combines chemical release data from EPA's Toxics Release Inventory (TRI) with toxicity data and population data from the U.S. Census. RSEI allows researchers to assess potential risks to communities, and draw attention to serious environmental injustices. Abt has also assessed the environmental justice impacts of proposed rulemakings, including the TSCA Dust-Lead Rulemakings and the Lead and Copper Drinking Water Rule.

EPA may, to some extent, be confined to existing legal and regulatory frameworks that make setting standards at the national level difficult, beyond single chemicals and well-defined chemical mixtures. However, like environmental justice efforts, cumulative risk and impact assessments have been around for years, and existing methods can be used now to help identify vulnerable communities where pollution reduction efforts should be focused.

Work With Us
Ready to change people's lives? We want to hear from you.
We do more than solve the challenges our clients have today. We collaborate to solve the challenges of tomorrow.