LIBRARY OF CONGRESS 
Figure 4. Diagnostic discriminant tool results and an interpolation fitting algorithm used 
here to classify lower James River benthic communities into categories distinguished by 
the type of stress experienced by those communities. Red shading indicates degraded 
benthic communities stressed by toxic contamination (posterior probability in 
Contaminant Group > 0.5), with higher color intensity indicating higher probabilities of 
contaminant effects (>0.5 to <0.7; > = 0.7 to <0.9; >=0.9). Salmon shading indicates 
degraded benthic communities stressed by other sources (posterior probability in 
Contaminant Group < = 0.5). Green indicates good benthic community condition. The 
Elizabeth River (er), Craney Island (ci), Willoughby Bay (wb), Nansemond River (nr), and 
Pagan River (pr) show contamination as likely source of stress. 
appendix I 
Addendum to the Report 
