investigations using other organisms are described later. The species 

 chosen for initial screening were a blue-green algae, Strain PR-6, a 

 green algae. Strain 580 and a Diatom, Strain N-1 (Cyclindrotheca). 

 The zone of inhibition of growth of these organisms around discs to 

 which selected phthalates were applied was the initial screening pro- 

 cedure. These preliminary studies indicate that the lower phthalate 

 analogs, dimethyl, diethyl and di-n-propyl phthalates, have some ef- 

 fect on the growth of these organisms. Table 6 summarizes early 

 results. 



25 



