of samples from the Gulf of Mexico for these esters was undertaken. 

 Reported analytical procedures, however, were not satisfactory to 

 quantitate the very low levels present in open-ocean samples. Also, 

 other ubiquitous pollutants, such as the polychlorinated hydrocarbons 

 (PCBs, DDT, DDE), were expected to interfere with the reported gas 

 chromatographic analyses of phthalates. Thus, appropriate separation 

 and other techniques were necessary prior to carrying out such anal- 

 ysis. Using a combination of solvent partitioning, deactivated-Florisil 

 column chromatography and electron-capture gas chromatography, 

 both chlorinated hydrocarbons and phthalate esters can be separated, 

 detected and quantitated at the parts per billion (ppb) level in biota 

 and sediment, and the parts per trillion (ppt) level in water. (Giam 

 et al., 1975). Data on samples from the Gulf of Mexico indicates that 

 the level of the most predominant phthalate ester. DEHP, di-2-ethyl- 

 hexyl phthalate, in biota and sediment are in the low ppb range and 

 in the low ppt range in water. The results of some of these analyses are 

 presented in Figure 3. This finding is consistent with the levels for 

 other organic pollutants in this area. 



Studies on the effects of phthalates on plankton have been initiated; 



Table 6 

 Growth Inhibition by Phthalates. 



ORGANISMi 



AMT. 

 ON PAD 



DMP DEP DPP DBP DEHP DIIP PA2 



Blue-green PR-6 0.1 mg 



1.0 mg 



10.0 mg 



Green alga 



Strain 580 0.1 mg 



1.0 mg 



10.0 mg 



Diatom 



(Cylindrotheca) 0.1 mg 



N-1 1.0 mg 



10.0 mg 



0-^ 

 11 

 20-23 







5-8 



20-25 







3 



12 







9 



11-13 





 13 



17 







7 



10 



3 

 6 



7 



30-36 

 36 

 36 



4 

 6 

 6 





 

 



1 

 1 



1 



1 



2 

 2 





 

 





 

 





 

 





 

 





 









 



2 





 3 



36 











30-34 











5-12 



^PR-6 — Agmenellum quadruplicatuni (Marine coccoid blue-green) 

 580 — Chlorella autotrophica (green alga) 

 N-1 — Cylindrotheca sp. (Diatom) 

 2DMP=Dimethyl-; DEP=Diethyl; DPP=Dipropyl-; DEHP-Di-2-ethylhezyl-; 

 DIIP=Diisodecyl-phthalate; PA=Phthalic Acid. 



^O^no inhibition; other numbers indicate diameter of zone of inhibition out from 

 pad in mm, complete inhibition of growth on plate equals 36 mm. 



24 



