Jump to main content or area navigation.

Contact Us

Health and Environmental Effects Research

WED Researchers Collaborate on Study To Aid USFS and NPS in Land Management Decisions

Atmospheric deposition of nitrogen (N) from fossil fuel and agricultural emissions is the largest single source of N to the northeastern United States and all U.S. mountain regions. Nutrient enrichment and acidification affect the water quality and biological condition of U.S. lakes. Critical loads (CLs) are a framework to guide the management and mitigation of such air pollution effects on ecosystems.

Scientists from NHEERL’s Western Ecology Division (WED), Colorado State University, and Syracuse University recently conducted a study of nutrient enrichment and acidification of U.S. lakes, specifically to show how empirical CLs of atmospheric deposition research impact land management decisions for the U.S. Forest Service (USFS) and the National Park Service (NPS). This research developed empirical CLs of N for freshwaters of the United States by conducting a synthesis of the literature and analyzing extant lake survey data.

The NPS and USFS air programs and their Federal land managers value this research for a number of reasons, including its recommendations of specific CLs for eutrophication and acidification that can be used as thresholds for the Sierra Nevada, the Rocky Mountains, and the northeastern United States. Also, its incorporation of data from long-term, spatially extensive studies—256 lakes in the Rockies and 20 in the Sierras from the Western Lakes study and some northeastern lakes from other lake studies—results in CLs that are more robust than those previously developed.

This work supports the ORD Administrator’s priorities of Improving Air Quality and Protecting America’s Waters and impacts EPA’s Office of Air, Office of Water, and Regions 1, 2, 8, 9, and 10.

Jump to main content.