Table 2.

Relative potencies (REPs) for AHR binding and human Toxic Equivalency Factors (TEFs).

HAH	Chlorination pattern	Beluga REPs for AHR binding	Mouse REPs for AHR binding	Rat REPs for AHR bindinga	2006 WHO TEFs for humans b
TCDD	2, 3, 7, 8,	1.00	1.00	1.0	1
TCDF	2, 3, 7, 8,	0.31	0.32	Not done	0.1
126	3, 3′, 4, 4′, 5	0.063	0.078	0.08	0.1
169	3, 3′, 4, 4′, 5, 5′	0.014	0.011	Not done	0.03
77	3, 3′, 4, 4′	0.013	0.0038	0.01	0.0001
81	3, 4, 4′, 5	0.0055	0.011	0.0004	0.0003
105	2, 3, 3′, 4, 4′	0.00018	0.00022	0.0023	0.00003
118	2, 3′, 4, 4′, 5	0.000071	0.00011	0.0011	0.00003
156	2, 3, 3′, 4, 4′, 5	0.00033	0.0013	0.0014	0.00003
128	2, 2′, 3, 3′, 4, 4′	0.00027	0.00025	Not done	no TEF

^acalculated from IC₅₀ reported in Bandiera et al., 1982

^breported in van den Berg et al., 2006