Figure 1. Boxplot of PCDD/F BSAFs calculated from data of studies cited in Table 2.

ERDC TN-DOER-R5

September 2004

Figure 1.

Boxplot of PCDD/F BSAFs calculated from data of studies cited in Table 2. Boxes are

medians, 25th and 75th percentiles. Whiskers are 10th and 90th percentiles. Balls are 5th

and 95th percentiles. Red (bolded) vertical lines are means

UNCERTAINTY ANALYSES: Estimates of uncertainty for TBP were determined using RSS

and bootstrap methods. The latter was also used to conduct nonparametric tests of significance

comparing TBP with measured mean tissue concentrations Ct. Calculations were performed

using individual mean BSAFs for each PCDD/F congener or homologue, and also an overall

mean BSAF for all PCDD/Fs.

Root Sum of Squares (RSS) Uncertainty. The first step in estimating the bioaccumulation

potential of a chemical in a sediment and the uncertainty surrounding the estimate is to calculate

TBP using Equation 1 with a BSAF for the chemical, relevant sediment concentration, organic

carbon content, and lipid content of a target organism, as in the data of Tables 3 and 4. For

example, substituting the data for 2,3,7,8-TCDD:

2,3,7,8-TCDD TBP = 0.433 * (0.474/0.0050365) * 0.0331176 = 1.350

(6)