Bis(2-ethylhexyl) phthalate

Toxicity to aquatic algae and cyanobacteria

Description of key information

In the reliable (RL 2) studies available no effects were observed (no LOEC was obtained) and it can securely be concluded that DEHP exerts no adverse effects on freshwater algae in concentrations between the actual (3 µg/L) and the apparent (100 µg/L) water solubility. Thus, no meaningful NOEC or EC10 could be derived.

Additional information

Overall, no measured LOEC values are available for algae, only nominal effect concentrations and “greater than” values.

Two studies exist with measured concentrations. In one study, the actual water solubility according to Staples et al. (1997) had been tested (3 µg/L) while in the other, a concentration within the range of reported apparent water solubilities was applied (100 µg/L). In both of these studies no effects were observed compared to the controls:

- Jonsson et al. (2003) tested the toxicity of DEHP on Pseudokirchneriella subcapitata according to the ISO 8692 standard. Depending on the test item, eleven to sixteen different concentrations were tested with a maximum of 0.003 mg/L. No solvent was used. Under the test conditions, EC10 (72h, biomass) and EC50 (72h, biomass) were above 0.003 mg/L estimated by a software using the non-linear regression method. Validity criteria were not reported and thus cannot be checked. However, as this study follows ISO standard, uses DEHP concentration not exceeding water solubility and was performed without solubilizers, it is considered as reliable and releant and taken as the key study for risk assessment.

- In the other study (Adams et al., 1995), Selenastrum capricornutum was exposed to 0.1 mg/l of DEHP according to US EP algal assay bottle test (1976). The test was performed under static conditions. No solvent was used and care was taken to avoid remaining floating test chemical. No toxic effect has been shown at the highest level tested (i. e. at or near the limit of apparent water solubility). NOEC = 0.1 mg/L (mean measured concentration). As the study was performed according to relevant standards and GLP procedure but no detailed information was given in the publication, therefore, the results are considered as reliable and support results from the key study.

Because in both studies no effects were observed (no LOEC was obtained) it can securely be concluded that DEHP exerts no adverse effects on freshwater algae in concentrations between the actual (3 µg/L) and the apparent (100 µg/L) water solubility. However, as no effects were observed (unbounded NOECs), no PNEC can be derived from these data.