||Environmental Research Lab., Gulf Breeze, FL. ;Fish and Wildlife Service, Jackson, MS. ;ABC Labs., Inc., Columbia, MO.
Industrial phosphate esters have been widely used for the past 30 years as plasticizers, hydraulic fluids, and gasoline additives because of their fire resistance and performance. A study by the U.S. Environmental Protection Agency indicated that a significant portion of the annual production of all hydraulic fluid was discharged into the environment as a result of leakage. The purpose of the study was to determine the chronic toxicity of Pydraul 50E, an alkyl-aryl phosphate ester hydraulic fluid, to lake trout (Salvelinus namaycush). Fry (24-days-old) were continuously exposed to 0, 2.6, 5.3, and 16 micrograms/L of Pydraul 50E for 120 days. All fish died in the 16 micrograms/L exposure, and growth was significantly less in the 5.3 micrograms/L exposure. A high incidence of light skin coloration (66%) and cataracts in one or both eyes (92%) also occurred in the 5.3 micrograms/L exposure. Bioconcentration factors for Pydraul 50E ranged from 462 to 5,500. Improved management of hydraulic fluid use is recommended to reduce environmental contamination.