Balance of Intake and Excretion of 20 Congeners of Polychlorinated Dibenzo-p-dioxin, Polychlorinated Dibenzofuran and Coplanar Polychlorinated Biphenyl in Healthy Japanese Men.

Abstract

Daily intake from meals, and excretion from feces and sebum of 20 congeners of polychlorinated dibenzo-pdioxin (PCDD), polychlorinated dibenzofuran (PCDF) and coplanar polychlorinated biphenyl (Co-PCB) were analyzed in healthy Japanese men who are considered to be a standard for the Japanese. Daily intake of these congeners was 84.2 ± 12.5 pg toxic equivalent (TEQ) and daily excretion from feces and sebum were 18.3 ± 5.9 and 23. 8 ± 5.6 pg TEQ, respectively, indicating 22% the daily intake of dioxins from meals is excreted from feces and 29% from sebum. 1,2,3,7,8-Pentachlorodibenzo-p-dioxin (1,2,3,7,2,3,4,7,3,4,7, and 3,3′,4,4′,5-pentachlorobiphenyl (3,3′, 4,4′,5-PeCB) were most abundant in TEQ, in meals, feces, sebum and blood. Co-PCBs were most efficiently excreted among three congener groups in TEQ, especially from sebum. Octachlorodibenzo-p-dioxin (OCDD), 2,3,7,3,7, and 3,3′,4,4′-tetrachlorobiphenyl (3,3′,4,4′-TCB) were well absorbed from intestine and excreted at more than 100% of intake, mainly from the sebum. In contrast, 1,2,3,4,7,2,3,4,7,2,3,7,8,2,3,7,8, were excreted at relatively low levels from sebum, although well absorbed from the intestine, and the excretion ratios were lowest among the 20 congeners. It was suggested that 80.5-85.2% TEQ of each congener-group might be absorbed from the intestine, after taking bile excretion into consideration.

Concentration-dependent TCDD elimination kinetics in humans: toxicokinetic modeling for moderately to highly exposed adults from Seveso, Italy, and Vienna, Austria, and impact on dose estimates for the NIOSH cohort

“…(Schlummer et al, 1998;Rohde et al, 1999;Kitamura et al, 2001a;Moser and McLachlan, 2001;Geusau et al, 2002). This model assumes that unchanged fecal TCDD stems from two sources: (1) elimination from circulating blood lipid through partitioning in the larger intestine (proportional to the adipose TCDD burden Q a in ng), and (2) pass-through elimination of unabsorbed TCDD from dietary intake ( Figure 2).…”

“…This average value was applied to the intake and excretion data on the other individuals considered for the determination of k a . Data on intake and excretion of unchanged TCDD for 18 individuals (serum lipid TCDD concentrations ranging from 2.8 to 80,900 ppt) from five studies (Schlummer et al, 1998;Rohde et al, 1999;Kitamura et al, 2001a;Moser and McLachlan, 2001;Geusau et al, 2002) were used to evaluate k a from Eq. (7) using the f abs estimated above.…”

“…In addition, there is evidence that unchanged TCDD partitions on a lipid basis into bile and thus is excreted into feces as well (Kitamura et al, 2001b). Five recent studies provide data that allow assessment of the rate of partitioning of TCDD from circulating lipids into fecal contents (Schlummer et al, 1998;Rohde et al, 1999;Kitamura et al, 2001a;Moser and McLachlan, 2001;Geusau et al, 2002).…”

Dioxins in bile in relation to those in the human liver and blood.

“…1,2,3,7,8,2,3,7,8,1,2,3,7,2,3,7,1,2,3,4,7,8,2,3,4,7,8,2,3,7,3,7,, octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,7,2,3,4,7, were well absorbed from the gastrointestinal tract after ingestion, and OCDD,2,3,7,3'4,3'4, were efficiently excreted from sebum but 1,2,3,4,7,8-HxCDD was scarcely excreted. In total-TEQ, about 22% of the ingested dioxins were excreted from feces and 29% from sebum, while the fate of the other 50% is not clear at present (Kitamura et al, 2001). Since the half-life of 2, 3,7,3,7, in humans has been estimated to be 5.8~9.5 years (Michalek et al, 1996;Ott and Zober, 1996), and 33 years for 2,3,4,7,8-PeCDF (Rohde et al, 1999), these dioxins might be subjected to enterohepatic circulation.…”

“…We have recently clarified that gastrointestinal absorption of dioxins is not directly associated with the number of chlorine atoms of the congeners, and each compound has its own characteristic features of metabolism (Kitamura et al, 2001). 1,2,3,7,8,2,3,7,8,1,2,3,7,2,3,7,1,2,3,4,7,8,2,3,4,7,8,2,3,7,3,7,, octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,7,2,3,4,7, were well absorbed from the gastrointestinal tract after ingestion, and OCDD,2,3,7,3'4,3'4, were efficiently excreted from sebum but 1,2,3,4,7,8-HxCDD was scarcely excreted.…”