250 H 
I I I I I I I 
1860 1880 1900 1920 1930 1940 1960 1980 
TOTAL PCBs 
COMBUSTION PAH 
1860 1880 1900 1920 1940 1960 1980 
LEAD 
Figure 9. History of sediment contamination by PCBs, PAH, and lead In 
central Puget Sound from 1860 to 1980. 
80 
