You might not be as safe as you think: Cumulative Impacts

Updated: Nov 12, 2019

Dr. Yukyan Lam, a staff scientist with the Natural Resources Defense Center, explaining the importance of evaluating cumulative impacts when addressing environmental health.

“One of the biggest problems in public health is public health,” announced Michele L. Roberts, the National Coordinator of the Environmental Justice and Health Alliance for Chemical Policy Reform (EJHA).

On November 2nd, the EJHA held a National People’s Town Hall session at the American Public Health Association’s annual meeting in Philadelphia. Hosted by The Dornsife School of Public Health at Drexel University, the conference focused on the effects of cumulative impacts and ways of addressing them through policy.

“Cumulative impacts” was defined at the town hall as the risks and impacts caused by multiple pollutants in both isolation and when interacting with one another, which pose immense threats to communities located close to the high risk facilities. Speakers had a general consensus that the greatest problem in regards to cumulative impacts is the fact that the government does not directly consider it when creating regulations. Dr. Nicky Sheats, director of the Center for the Urban Environment at Thomas Edison State University, explained that pollutants have individual standards when being regulated. The main concern with this is that the cumulative impact can be detrimental even if individual standards are not violated.

Cumulative impacts also don’t necessarily apply to just pollutants; they encompass any form of human activity. One example of a cumulative impact would be if a project minorly decreased both the quality and quantity of drinkable water in an area. Though individually the results may be negligible, combined, these effects can greatly devastate a community.

This was echoed by other panelists such as Dr. Yukyan Lam, a staff scientist with the Natural Resources Defense Center, who believes it is imperative that we must look at pollutants holistically to reduce their negative effects on public health. While there are no cumulative impact regulations, as there are with individual pollutants such as carbon dioxide and mercury, the assessment of cumulative impacts in the National Environmental Policy Act (NEPA) documents is required by Council on Environmental Quality (CEQ) regulations[1,2]. However, the complexity of the topic makes cumulative impacts hard to address, and so the EPA first determines the potential scope of cumulative impacts and whether they would be significant [1].

The EPA also defines cumulative impacts more broadly as the effects of an action added to another in a particular place and within a particular time [1]. This general definition not only encompasses the conglomerated effects of different pollutants, but also the accumulation of environmental consequences over time. This only increases the difficulty of analyzing the potential repercussions of a project’s actions on environmental and ecological resources. Because of this, there is no single procedure for determining the appropriate scope and extent of a cumulative effects analysis. Ultimately, the practitioner must determine the methods and extent of the analysis based on the size and type of the project proposed, its location, potential to affect environmental resources, and the health of any potentially affected resources [2].

Though there exists no singular procedure for analyzing the potential cumulative impact on an area, the EPA and CEQ have outlined some general guidelines. Cumulative effect is simply the summation of direct and indirect effects of past actions, present actions, reasonable project alternatives, and other future actions. However, cumulative impacts do not necessarily result in a greater negative effect. Special designations or ongoing regulations may limit the adverse effects. However, as emphasized by many panelists at the National Environmental Justice Townhall, some areas and resources may be more sensitive to and experience greater adverse effects when faced with multiple stresses. As such, the EPA recommends that potential mitigation strategies are also addressed when reviewing documents.

The National Environmental Justice Town Hall highlighted the importance of addressing cumulative impacts in addition to the individual impacts of different pollutants and other stressors. With around 124 million people living in fence line communities, defined as individuals who live within 3 miles of a high risk facility, these cumulative effects could be detrimental to citizens [3]. As such, it is important to also analyze the potential effects of multiple stressors, not just in the present, but as they build up over time. This procedure may be necessary even if individually the stressors do not violate regulations. However, though it is true that multiple stressors can magnify environmental consequences, it is also important to fall under the fallacy that adding more stressors will always results in greater adverse effects on both individuals and the environment.




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