Persistent, bioaccumulative, and toxic pollutants (PBTs) are long-lasting substances that can build up in the food chain to levels that are harmful to human and ecosystem health. They are associated with a range of adverse human health effects, including effects on the nervous system, reproductive and developmental problems, cancer, and genetic impacts. A new Battelle-led study will enable a greater understanding of one group of PBTs: dioxin-like compounds. The study is part of the U.S. Environmental Protection Agency’s (EPA) PBT Research Initiative.

The EPA’s challenge in reducing risks from PBTs stems from the pollutants’ ability to travel long distances; to transfer easily among air, water, and land; and to linger for generations. The PBT Research Initiative identified the need to understand the contribution that urban areas may have as area sources of PBTs. In particular, the diversity of human activities characteristic of a city environment may increase the atmospheric loading of dioxin-like compounds (PCDDs, PCDFs, and coplanar PCBs) relative to rural areas.

The Urban Air Transect Study will characterize the levels and distribution of air concentrations of dioxin-like compounds across urban areas and nearby rural areas along a transect running parallel to the prevailing wind patterns. The goals of the study, which began in October 2000 in Oklahoma City, Okla., are to:

• provide data to clarify whether or not urban air tends to contain significantly higher concentrations of dioxin-like compounds than rural air; and
• establish a topography of an urban air profile for dioxin-like compounds.

Battelle’s study design accounted for the prevailing wind patterns, terrain, population, population density, transportation corridors, industry, and local dioxin point sources. In cooperation with the Air Quality Management Division of the Oklahoma Department of Environmental Quality (DEQ), eight monitoring sites were located in and around Oklahoma City. A transect was located through the city based on prevailing wind patterns. Six sites were located along the transect to capture air that moves from rural areas, through the urban area, and back out to rural areas. Two other sites were located about 40 miles to the west of the urban center outside of the prevailing wind pattern.

Working with DEQ staff, the sites were located in October and November 2000, ambient air samplers were placed at the end of November, and samples were collected from December 1-20, 2000. The samplers were run continuously during this period and field blanks were also collected.

The samples will be analyzed for a range of PCDDs, PCDFs, and coplanar PCBs at EPA’s Environmental Chemistry Laboratory. Weather data were also collected for correlation with the laboratory and field results. Statistical analysis and additional sampling are expected to be performed in 2001.

This work is being performed for EPA’s National Center For Environmental Assessment under EPA Contract 68-C-00-122.

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