Table 5.

Estimate of half-lives (in years) of PCB grouping and specific congeners, p,p′-DDE, and HCB.

	Model 1* Unadjusted Half-life	Model 2** Adjusted Half-life	Model 3*** Adjusted Half-life LR Method (all cases)	Model 4**** Adjusted Half-life LR Method (no increase cases)
	Mean	Mean	Mean	Mean
Σ16PCB50%a	8.4	7.91	6.64	5.15
Σ8PerPCBsb	12.54	13.19	10.35	6.18
Σ6NONPerPCBsc	5.46	4.5	4.08	3.5
p,p′-DDE	35.62	55.78	20.9	7.2
HCB	69.52	84.74	73.45	8.67
PCB IUPAC#a
105	8.43	7.19	4.47	2.36
118	7.68	6.49	5.4	3.71
138 [+163+164]d	22.32	24.67	27.75	5.82
153	14.13	16.32	13.18	5.55

^*Half-life estimated with Tobit regression without adjusting for any covariates

^**Half-life estimated with Tobit regression adjusted for vectors of intake and controls

^***Half-life estimated with linear regression (LR) using all respondents (adjusted for vectors of intake and controls)

^****Half-life estimated with linear regression (LR) eliminating respondents with increased POP level (adjusted for vectors of intake and controls)

^aCongeners with ≥ 50% detection rate in MAWBs: IUPAC #s: 52, 70, 74, 84, 87, 95, 99, 101[+90], 105, 110, 118, 149[+123], 138[+163+164], 153, 180, 187

^bSum of IUPAC#s: 74, 99, 105, 118, 138[+163+164], 153, 180, 187

^cSum of IUPAC#s: 52,84,95,101,110,123[+149]

^dBracket indicates ‘minor’ congener based on aroclor concentration (Hansen, 1999)