Case report: human exposure to dioxins from clay.
BACKGROUND
For the general population, the dominant source of exposure to dioxin-like compounds is food. As part of the University of Michigan Dioxin Exposure Study (UMDES), we measured selected polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) in serum of 946 subjects who were a representative sample of the general population in five Michigan counties.


METHODS
The total toxic equivalency (TEQ; based on 2005 World Health Organization toxic equivalency factors) of serum from the index case was 211 ppt on a lipid-adjusted basis, which was the highest value observed in the UMDES study population. This subject had no apparent opportunity for exposure to dioxins, except that she had lived on property with soil contaminated with dioxins for almost 30 years, and had been a ceramics hobbyist for > 30 years. Soil from her property and clay that she used for ceramics were both contaminated with dioxins, but the congener patterns differed.


CONCLUSIONS
The congener patterns in this subject's serum, soil, and ceramic clay suggest strongly that the dioxin contamination in clay and not soil was the dominant source of dioxin contamination in her serum. RELEVANCE TO PUBLIC HEALTH PRACTICE: It appears that ceramic clay, in particular the process of firing clay with unvented kilns, can be a significant nonfood and nonindustrial source of human exposure to dioxins among ceramics hobbyists. The extent of human exposure from ceramic clay is unclear, but it may be widespread. Further work is needed to more precisely characterize the routes of exposure.
Franzblau
Alfred
A
Department of Environmental Health Sciences, University of Michigan School of Public Health, 109 South Observatory Street, Ann Arbor, MI 48109, USA. afranz@umich.edu
Hedgeman
Elizabeth
E
Chen
Qixuan
Q
Lee
Shih-Yuan
SY
Adriaens
Peter
P
Demond
Avery
A
Garabrant
David
D
Gillespie
Brenda
B
Hong
Biling
B
Jolliet
Olivier
O
Lepkowski
James
J
Luksemburg
William
W
Maier
Martha
M
Wenger
Yvan
Y
D000368:Aged; D000538:Aluminum Silicates; D000077215:Clay; D004147:Dioxins / Q000097:blood / Q000633:toxicity*; D004781:Environmental Exposure; D005260:Female; D006801:Humans
D000538:Aluminum Silicates; D004147:Dioxins; D000077215:Clay