Estimated number of cancers, in excess of the background rate, per 1,000,000 individuals exposed to carcinogenic PAHs. Calculations are based on average fish consumption rates; where LFT concentrations have been substituted for fish tissue concentrations. Data from all sites located in each area of the river (upriver, downriver and within the Superfund) were averaged for the wet and dry seasons and observations associated with tar removal remediation activities are presented separately. Error bars represent 95% confidence intervals, based on variability in the PSD measured concentrations for each site-season, and only one observation was made at the downriver site during tar removal. See table 1 for statistical analyses of these data.