Table 3.

Estimated chronic steady‐state body burdens of TCDD and corresponding estimated human daily intakes (EHDI) at NOAEL and LOAELs in the pivotal studies (SCF, 2001)

Study	Endpoint	NOAEL	LOAEL	Estimated maternal steady‐state body burdena (ng/kg bw)	Associated EHDId (pg/kg bw per day)
Mably et al. (1992a)	Holzman rats: decreased sperm count in male offspring	–	64 ng/kg bw single bolus dose by gavage	100b	50
Gray et al. (1997a)	Long‐Evans rats: accelerated eye opening and decreased sperm count in male offspring	–	50 ng/kg bw single bolus dose by gavage	80b	40
Faqi et al. (1998)	Wistar rats: decreased sperm production and altered sexual behaviour in male offspring	–	Maintenance of 25 ng/kg bw by s.c. injections	40b	20
Ohsako et al. (2001)	Holzman rats: decreased anogenital distance in male offspring	12.5 ng/kg bw single bolus dose by gavage	–	20c	10
		–	50 ng/kg bw single bolus dose by gavage	80c	40

bw: body weight; GD: gestation day; LOAEL: lowest‐observed‐adverse‐effect level; NOAEL: no‐observed‐adverse‐effect level; TCDD: 2,3,7,8‐ tetrachlorodibenzo‐p‐dioxin; s.c.: subcutaneous.

^aIncrement over background. Estimated background body burden from feed in rats is approximately 4 ng TEQ/kg bw (WHO, 2000). The maternal body burdens were increased by a factor of 2.6 for the difference in the ratio between levels in the fetus and mother after a single vs repeated dose.

^bComposite value resulting from pseudo steady‐state body burden and acute body burden on GD15.

^cMaternal body burden at GD16.

^dEstimated chronic Human Daily Intake.