National Human Exposure Assessment Survey Begins

Article excerpt

For decades researchers have been measuring and tracking environmental pollutants. Volumes of information have been gathered about air, water and food pollution, and more recently, about indoor air contaminants. But scientists have yet to fully understand the last and most important pieces of the puzzle: which pollutants are most likely to find their way into the human body and cause the most harm? And for those that do, by which pathways--inhalation, ingestion, or absorption through the skin--do they enter the human body.

To answer these questions, the U.S. Environmental Protection Agency has launched a major study called the National Human Exposure Assessment Survey (NHEXAS). This survey will gather information about the magnitude, extent and causes of human exposure to specific pollutants, information scientists can use to conduct risk assessments. NHEXAS will also measure the total "dose" of selected pollutants that survey participants receive.

EPA has awarded the Research Triangle Institute (RTI) a three-year, $4.99 million cooperative agreement to conduct a NHEXAS pilot study.

Lead and arsenic will be the primary focus of the pilot study, but researchers will also gather information about the exposure of individuals to benzene and other volatile organic compounds. To plan future study designs, the RTI team will collect exposure data for chlorpyrifos and other pesticides, and for benzo(a)pyrene and other polynuclear aromatic hydrocarbons.

"We chose metals, volatile organics, pesticides, and polynuclear aromatics for the pilot study because of their toxicity, prevalence in the environment, and relative risk to humans," explained Dr. Edo Pellizzari, principal investigator for the NHEXAS pilot study. "These classes of compounds and the expected combination of chemicals, exposure media, and routes of exposure will demonstrate and challenge currently available analytical techniques. …