o 



TO 



1 50 



1 40 



c 



<D 



° 5-. 



Sy 130 



a ct> 



CD cr« 



o 



CD 



£ 

 o 



CD 

 CD 



20 



1 1 



1 00 



85 86 



87 



88 

 year 



89 90 9 1 



Figure 4d. Annual geometric mean concentrations of selected chemicals in mollusks. 



CO 



c: 

 o 



00 



2500 



2300 



o ^ 21 00 

 u i 



CD 



CT> 



<E =* 1 900 

 o 



CD 



o 



CD 



CD 



700 



1 500 



85 86 87 88 89 90 9 1 



year 



Figure 4e. Annual geometric mean concentrations of selected chemicals in mollusks. 



19 



