A SUMMARY OF THE ACUTE TOXICITY OF 14 PHTHALATE-ESTERS TO REPRESENTATIVE AQUATIC ORGANISMS

Acute aquatic toxicity studies were performed with 14 commercial phtha late esters and representative freshwater and marine species. The 14 e sters were dimethyl phthalate; diethyl phthalate; di-n-butyl phthalate ; butyl benzyl phthalate; dihexyl phthalate; butyl 2-ethylhexyl phthal ate; di-(n-hexyl, n-octyl, n-decyl) phthalate; di-(2-ethylhexyl) phtha late; diisooctyl phthalate; diisononyl phthalate; di-(heptyl, nonyl, u ndecyl) phthalate; diisodecyl phthalate; diundecyl phthalate; and ditr idecyl phthalate. Phthalate esters with alkyl chain lengths of four ca rbon atoms or fewer were determined to be acutely toxic at concentrati ons ranging from 0.21 to 377 mg/L depending on the ester and the solub ility of the test chemical in water. There was a general trend for the lower-molecular-weight phthalate esters (C-1 to C-4 alkyl chain lengt hs: dimethyl phthalate; diethyl phthalate; di-n-butyl phthalate; and b utyl benzyl phthalate) to become more toxic with decreasing water solu bility for all species tested. There were only minor differences in sp ecies sensitivity to each of the phthalate esters. Phthalate esters wi th alkyl chain lengths of six carbon atoms or more were not acutely to xic at concentrations approaching their respective aqueous solubilitie s. Insufficient mortality occurred to calculate either LC50 or EC50 va lues or acute no-observed-effect concentrations for these higher-molec ular-weight phthalate esters. The lack of toxicity observed for the hi gher-molecular-weight phthalate esters resulted from their limited wat er solubility (less than or equal to 1.1 mg/L).