The environmental chemical data has been an integral part of NHANES for more the 30 years, beginning with NHANES II (1976-80) when blood lead levels were first measured in the U.S. population. These same chemicals were measured in the specialized Hispanic HANES (1982–1994), as well. For NHANES III (1988-94), the field was enlarged beyond measurements of blood lead levels to include cadmium, cotinine, and selenium, as well as selected pesticides from blood and urine
Since the continuous survey began in 1999, NHANES has become a key source for bio-monitoring of environmental chemical exposures. Spearheaded by laboratories at CDC’s National Center for Environmental Health (NCEH), where many of the specimens are stored and analyzed, the NHANES environmental chemical data are highlighted in the National Report on Human Exposure to Environmental Chemicals, which was first published in 2001. As of 2009, exposure data are generated from urine and blood samples for more than 200 environmental chemicals including volatile organic compounds, heavy metals, pesticides and their metabolites, and many other chemicals. While other environmental indicators including lead dust, household water collection, hair, and questions related to exposures inside and outside the home are also obtained in NHANES, this tutorial focuses only on blood and urine. To learn about which chemicals are collected in each survey cycle, you can view the Environmental and Related Chemicals Measured in Blood, Serum or Urine in NHANES [PDF - 154 KB] document.