Dioxins in Background Ambient Air

The U.S. Environmental Protection Agency designed and initiated the National Dioxin Air Monitoring Network (NDAMN) in 1998 to provide information that may link sources with human exposures to dioxin-like compounds. To achieve this goal, NDAMN is focused on three primary purposes. The first is to provide measurements of background atmospheric levels of dioxin-like compounds in different geographic regions of the United States. Relatively few studies have been conducted to measure ambient air levels in the United States. Studies that have been conducted lack geographic coverage and may not be representative of the Tnation as a whole. The second purpose is to determine the atmospheric levels of dioxin-like compounds in agricultural areas where livestock, poultry, and animal feed crops are grown. This is directed toward a better understanding of human exposure to dioxin-like compounds. Dioxin contamination of animal feed crops is important to characterize and is a primary concern of NDAMN. The third purpose is to provide data to evaluate results from long-range transport and deposition air models. Long-range transport and deposition air modeling are important in understanding the sources and impacts on levels of dioxin-like compounds in the environment, especially in ambient air. NDAMN results will be beneficial in the use and improvement of such models.

NDAMN now consists of 35 sites situated in rural and remote locations across the United States. An ambient air sample is collected for a 4-week period, every 3 months, concurrently at each site. Each of these samples is analyzed for dioxin-like compounds, including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and co-planar polychlorinated biphenyls (PCBs). Battelle operates the 35 NDAMN sites for EPA with the assistance of contract field operators, National Park staff, and others. To date, over 500 NDAMN ambient air samples have been collected. Battelle has also created a database for EPA that serves as a tool for archiving temporal monitoring results and for assessing and analyzing results. With Battelle’s assistance, EPA will soon launch an Internet site that gives a description of NDAMN, background information on dioxins, their sources and effects, links, and most importantly, access to the database and reports. The Internet site, that includes the 2000 NDAMN Annual Report, will be available to the public in the near future. EPA intends to operate NDAMN and add monitoring sites over the next few years.

For more information about NDAMN, contact Karen Riggs at (614) 424-7379, riggsk@battelle.org.