Table 1.
Associated doses used in the NTP two-year studies of dioxin and dioxin-like compounds.
| Compounds | Structures | TEFa | Core groups (animal, dose, route) |
|---|---|---|---|
| 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (Group 1 carcinogenb) |
|
1 | TR201c: male & female Swiss-Webster mice; 0.001 (male) and0.005 (female) μg; dermal exposure without initiation
TR209: male & female Osborne-Mendel rats; 0.01, 0.05, 0.5 μg/kg; gavage exposure TR209: male & female B6C3F1 mice; 0.01, 0.05, 0.5 μg/kg (male), 0.04, 0.2, 2 μg/kg (female); gavage exposure TR521: female Harlan Sprague-Dawley rats; 3, 10, 22, 46, 100 ng/kg; gavage exposure |
| 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) (Group 2A carcinogenb) |
|
0.1 | TR520: female Harlan Sprague-Dawley rats; 30, 100, 175, 300, 550, 1000 ng/kg; gavage exposure |
| 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) (Group 3 carcinogenb) |
|
0.5 | TR525: female Harlan Sprague-Dawley rats; 6, 20, 44, 92, 200 ng/kg; gavage exposure |
a
Toxic equivalency factor (Van den Berg et al., 1998, 2006).
b
To humans, TCDD is classified as carcinogenic chemical, PCB126 as probable carcinogenic chemical; PeCDF is not classifiable as to carcinogenicity by International Agency for Research on Cancer (IARC) (http://monographs.iarc.fr/ENG/Classification/index.php).
c
National Toxicology Program (NTP) study report number.