Assessing Dioxin Exposure

The pathways of human exposure to dioxins and related persistent bioaccumulative toxins (PBTs) include exposure routes such as inhalation, ingestion, and dermal contact. Battelle assists the U.S. Environmental Protection Agency’s (EPA’s) National Center for Environmental Assessment (NCEA) in investigating exposures via these pathways.

Battelle estimates an artist’s exposure to dioxins via three exposure pathways. Skin rinse (dermal transport), air particle (inhalation), and food and drink (ingestion) samples were collected during and after artisan subjects performed clay artwork activities.

In 1996, as a result of investigations into the source of dioxin contamination in chicken fat, dioxins were measured at relatively high levels in ball clay, which is used as a component of chicken feed. Ball clays, in addition to their use as an anticaking agent in feed, are extremely malleable, making them an important resource for the ceramic industry. Because artisans use ball clay to make pottery and related products, the EPA initiated an investigation of the potential dioxin exposures of artisans. Battelle is assisting the EPA’s NCEA by conducting a field study to assess exposure of artisans working in a ceramics studio. Artists may be exposed to dioxin-contaminated clay via three pathways: (1) particle inhalation, (2) incidental ingestion of ball clay from eating in the work area, and (3) dermal contact from working with the clay. Instead of measuring dioxin concentrations directly, Battelle’s program uses the total clay concentrations in the studio’s air and loadings onto the food or drink near the work area, and onto the work surfaces, in order to estimate artisans’ exposure to dioxins through contact with ball clay. Dioxin concentrations in ball clay, measured during the aforementioned investigation of dioxins in chicken fat, are used to calculate theoretical dioxin exposures. Battelle is conducting the field study at The Ohio State University Ceramics Department. In a separate project to assess dietary exposure, Battelle has additionally been contracted by EPA’s NCEA to measure a wide variety of PBTs which include pesticides, polycyclic aromatic hydrocarbons, polychlorinated naphthalenes, brominated diphenyl ethers, lead, and cadmium in milk samples collected around the United States. EPA estimates that greater than 90% of human exposure to dioxin is from dietary consumption. Of this total dietary exposure, 15% of dioxin consumption is from milk. Battelle has optimized a sample preparation procedure in order to efficiently extract these compounds from milk for analysis by mass spectrometry.

For more information about the artisan exposure program, contact Dr. Ryan James at (614) 424-7954, jamesr@battelle.org. For more information about the program to assess PBTs in milk, contact Kim Andrews at (614) 424-5254, and andrewsk@battelle.org.