FIGURE 7-5 Dose-response curves fitted to cord-blood Hg data for the linear, square root, and log transformations. Source: E. Budtz-Jørgensen, University of Copenhagen, unpublished material, November 12, 1999.

zero exposure) (E. Budtz-Jørgensen, Copenhagen University, N. Keiding, Copenhagen University, and P. Grandjean, University of Southern Denmark, unpublished material, May 5, 2000). The majority of exposures resulted in hair Hg concentrations that exceeded 5 ppm (24 ppb cord blood). The interquartile range for hair Hg concentration was 3 to 8 ppm (13 to 40 ppb for cord blood) (Grandjean et al. 1992). When models are fitted to the data, they are really capturing the shape of the dose response in this middle range of exposure, as illustrated in Figure 7-5. The figure shows dose-response curves fitted to hair Hg data for the