1.20 r 



1.00 



Q. 





 D 

 ■D 

 ■(/) 



I- 



Q 

 Q 



o 



0.80 



0.60 



0.40 



0.20 



0.00 



69 



71 



I 



73 



Year 



JL 



± 



J 



75 76+77 



Fiaure 2. Geometric mean total DDT residues (p,p' - homologues) 

 in freshwater fish, 1969-1976/77. 



104 



