TEF
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TEF (TCDD equivalency factor, toxic equivalency factor), a relative toxicity factor of a PCDD/F or PCB congener as related to TCDD. TEF values vary from 1 to 0.00001 or 0 (Table 4; see also TEq). The latest re-evaluation of TEF values was that by WHO in 1998, and these TEF values have been used in this booklet as WHO-TEF for PCDD/Fs and PCB-TEF for PCBs. TEq = ΣTEFi*Ci, where Ci is the amount (or concentration) of congener i.
Table 4. Toxic equivalency factors for all PCDD/Fs and PCBs that have a TEF>0. Other congeners are not supposed to have dioxin-like effects. IUPAC numbers for PCBs are given in parenthesis.
| Congener | WHO-TEF |
|---|---|
| PCDDs | |
| 2,3,7,8-TCDD | 1 |
| 1,2,3,7,8-PeCDD | 1 |
| 1,2,3,4,7,8-HxCDD | 0.1 |
| 1,2,3,6,7,8-HxCDD | 0.1 |
| 1,2,3,7,8,9-HxCDD | 0.1 |
| 1,2,3,4,6,7,8-HpCDD | 0.01 |
| OCDD | 0.0001 |
| PCDFs | |
| 2,3,7,8-TCDF | 0.1 |
| 1,2,3,7,8-PeCDF | 0.05 |
| 2,3,4,7,8-PeCDF | 0.5 |
| 1,2,3,4,7,8-HxCDF | 0.1 |
| 1,2,3,6,7,8-HxCDF | 0.1 |
| 1,2,3,7,8,9-HxCDF | 0.1 |
| 2,3,4,6,7,8-HxCDF | 0.1 |
| 1,2,3,4,6,7,8-HpCDF | 0.01 |
| 1,2,3,4,7,8,9-HpCDF | 0.01 |
| OCDF | 0.0001 |
| Non-ortho-PCBs | |
| 3,3’,4,4’-TCB (77) | 0.0001 |
| 3,4,4’,5-TCB (81) | 0.0001 |
| 3,3’,4,4’,5-PeCB (126) | 0.1 |
| 3,3’,4,4’,5,5’-HxCB (169) | 0.01 |
| Mono-ortho-PCBs | |
| 2,3,3’,4,4’-PeCB (105) | 0.0001 |
| 2,3,4,4’,5-PeCB (114) | 0.0005 |
| 2,3’,4,4’,5-PeCB (118) | 0.0001 |
| 2’,3,4,4’,5-PeCB (123) | 0.0001 |
| 2,3,3’,4,4’,5-HxCB (156) | 0.0005 |
| 2,3,3’,4,4’,5’-HxCB (157) | 0.0005 |
| 2,3’,4,4’,5,5’-HxCB (167) | 0.00001 |
| 2,3,3’,4,4’,5,5’-HpCB (189) | 0.0001 |