Pentadecan-15-olide

Long-term toxicity to fish

Description of key information

Read-Across (EC Number: 422-320-3), OECD Guideline 210, EPA OPPTS 850.1400 , GLP, Key study, validity 2:
33d-NOEC = 0.027 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.027 mg/L

Additional information

A study was performed on a read-across substance (EC Number: 422-320-3) to assess the effects of the test material on freshly laid eggs of the fathead minnow (Pimephales promelas). The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 210, "Fish, Early-Life Stage Toxicity Test", US Code of Federal Regulations, Title 40, Part 797, Section 1600 and the US EPA Draft Ecological Effects Test Guideline OPPTS 850.1400. This supporting substance is considered adequate for read-across purposes (see Iuclid section 13 for justification).

Freshly laid eggs were exposed to an aqueous solution of test material over a range of nominal test concentrations of 0.0050, 0.016, 0.050, 0.16 and 0.50 mg/l for a period of 33 days at a temperature of 22.5 to 25°C under flow-through test conditions (some of the temperatures are out of range compared to OECD 210 which recommends use of 25±2°C for this species and not more than 1.5°C change per day or between reps. The deviation is also concentration dependent and in many cases a 0.5 to 1°C difference is observed between the controls and the highest test concentration with the highest temperatures in the control. It is quite possible that this could have influenced the growth of juvenile fish positively compared to the exposed fish. Significant mortality also occurred in one out of two replicates at the highest concentration. As no mortality was observed in the second replicate and there was otherwise no experimental difference between the two replicates, this cannot be attributed to the test substance and undermines the validity of the study.

 

The results of analysis of the untreated test media showed measured, centrifuged concentrations to be 0.0018, 0.0025, 0.0077, 0.027 and 0.11 mg/l. These low measured test concentrations were considered to be due to the low solubility of the test material in water and the associated problems of dosing materials of low solubility using auxiliary solvents, instability in water and losses due to volatility.

Given the decline in measured test concentrations it was considered appropriate to calculate the results based on the mean measured test concentrations of the centrifuged test media.

 

The NOEC and the LOEC, based on the mean measured test concentrations of the centrifuged test media, were considered to be 0.027 mg/l and 0.11 mg/l respectively, in terms of length and weight. Nevertheless, the result should be considered an extreme worst case value as significant differences were also noted between the replicates of the solvent control and between the control and the solvent control.