Differential bioaccumulation of PCBs in two songbirds.

<p><b>A</b>) Total PCB concentration (ppb, mean±SE) were analyzed in blood samples of black-capped chickadees and song sparrows from northeastern New York State. ANOVA (inset) was performed on log-transformed data. Non-overlapping letters indicate statistical difference between groups. <b>B</b>) The PCB chlorination profiles for black-capped chickadees and song sparrows by region. <b>C</b>) Principal component analysis of PCB congener profiles from black-capped chickadees and song sparrows from the region with highest historical PCB contamination (++ Hudson). PC1 accounts for 21% of variability, and PC2 accounts for 19.3% of variability. <b>D</b>) The proportion of lower chlorinated (4-Cl+5-Cl) and higher chlorinated (7-Cl+8-Cl) PCBs in black-capped chickadees and song sparrows from the + Hudson and ++ Hudson regions.