Bis(2-ethylhexyl) phthalate

Short-term toxicity to fish

Description of key information

From the short-term toxicity studies it can be concluded that DEHP has no acute effect on fish at concentrations far exceeding its water solubility. Therefore, no LC50 can be derived.

Additional information

The short term toxicity of DEHP to fish has been tested in different studies of varying quality. The RAR, 2008 reports all these studies. No new studies have been produced since then. Both static, semistatic and flow-through test regimes have been applied. In many of the tests there has been problems maintaining test concentrations.

In studies where both nominal and measured test concentrations are reported the measured concentrations are often lower. Therefore studies where only nominal test concentrations are reported may underestimate the toxicity of DEHP.

The key study is a work performed by Springborn Bionomics laboratories (1983 and 1984) and published by Adams et al. (1995). Studies were conducted in accordance with US EPA and GLP standards on 4 species of fish: Fathead minnow, Bluegill sunfish, Sheepshead minnow or Rainbow trout. Tests were performed in static or flow though conditions. No solvent was used and care was taken to avoid remaining floating test chemical. In all cases, no toxicity was observed at the level tested (mean measured concentrations between 0.16 and 0.67 mg/L). Therefore in short term exposure (96h) DEHP concentrations near or above the limit of water solubility of 3 µg/L do not induce hazardous effects to fish.

This result is supported by DeFoe et al. (1990) who showed no adverse nor anormal behaviour of Fathead minnows and Medaka exposed in flow through systems during 96h to saturated solution of DEHP (mean measured concentrations 0.326 and 0.67 mg/L, respectively). In his study report, Scholtz (1990) showed no toxicity even at the unrealistic environmental concentration of 100 mg/L. It shall be noted that, in several other studies, concentrations up to 3,000 mg/l have been tested without causing mortality. Only one study reported a LC50 for rainbow trout at the nominal concentration of 540 mg/l (Hrudey et al., 1976). The mortality in this study is assumed by the authors to be caused by physical action. Considering the physical effect and/or unrealistic concentration tested, these studies are considered as unreliable. However, these studies support that DEHP has no hazardous effect at concentration at or above its water solubility and if effects are observed at very high concentrations it is due to physical effects. Therefore, from the short-term toxicity studies it can be concluded that DEHP has no acute effect on fish at concentrations far exceeding its water solubility.