Estimates of the half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Vietnam Veterans of Operation Ranch Hand.
The half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD; commonly known as dioxin) in serum has been measured in 36 Air Force Vietnam veterans of Operation Ranch Hand, which was the operation that aerially sprayed the herbicide Agent Orange in Vietnam. From serum specimens taken in 1982 and 1987, the median half-life of 2,3,7,8-TCDD in these Ranch Hand veterans was found to be 7.1 yr (95% confidence interval about the median of 5.8-9.6 yr). These veterans reported no civilian exposure to dioxin or herbicides. Concentrations of 2,3,7,8-TCDD in the 1982 serum specimens from these veterans ranged from 16.9 to 423 parts per trillion on a lipid weight basis. The half-life estimates were not associated with the concentration of 2,3,7,8-TCDD in the 1982 serum specimens. This half-life of 7.1 yr is much longer than the half-life of 2,3,7,8-TCDD reported in animals but is consistent with recent evidence from other human exposures to 2,3,7,8-TCDD.
Pirkle
J L
JL
Division of Environmental Health Laboratory Sciences, Centers for Disease Control, Atlanta, Georgia 30333.
Wolfe
W H
WH
Patterson
D G
DG
Needham
L L
LL
Michalek
J E
JE
Miner
J C
JC
Peterson
M R
MR
Phillips
D L
DL
D000328:Adult; D000818:Animals; D004147:Dioxins / Q000097:blood*; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D010573:Pesticide Residues / Q000097:blood*; D000072317:Polychlorinated Dibenzodioxins / Q000097:blood*; D013997:Time Factors; D014728:Veterans; D014744:Vietnam
D004147:Dioxins; D010573:Pesticide Residues; D000072317:Polychlorinated Dibenzodioxins