Reaction mass of 2-(3-ethylphenyl)oxirane and 2,2’-(1,3-phenylene)dioxirane and 2,2'-(1,4-phenylene)dioxirane

Endpoint summary

Additional information

Testing was carried out on the following endpoints using the following guidelines:

Short-term toxicity to fish - OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Regulation (EC) No. 440/2008.

Short-term toxicity to aquatic invertebrates - OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp, Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Short-term toxicity to aquatic algae and cyanobacteria - OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 440/2008.

Short-term toxicity to microorganisms - OECD Guidelines for Testing of Chemicals (1984) No 209 "Activated Sludge, Respiration Inhibition Test", Method C.11 of Commission Regulation (EC) No. 440/2008 and US EPA Draft Ecological Effects Test Guidelines OPPTS 850.6800.

The results of the studies are detailed below:

Short-term toxicity to fish:

The 96-Hour LC₅₀based on nominal test concentrations was 2.4 mg/l with 95% confidence limits of 1.8 ‑ 3.2 mg/l. The No Observed Effect Concentration was 1.0 mg/l.

Analysis of the test preparations at 0, 24 and 96 hours showed measured test concentrations to range from 87% to 105% of nominal with the exception of the 0.56 mg/l test concentration at 24 hours which showed a measured concentration of 204% of nominal. Analysis of the corresponding frozen duplicate sample showed a measured concentration of 189% of nominal. Given that the analysis of the 0.56 mg/l test concentration at 0 hours showed a measured concentration of 104% of nominal it was considered that a sampling error had occurred at 24 hours. This was considered not to affect the study as this concentration was below the NOEC and all other measured concentrations were within the 80% to 120% acceptance limits. It was therefore considered justifiable to base the results on nominal test concentrations only.

N.B. Under the test conditions employed for the ecotox studies, the test item was shown to be sufficiently stable over the period of media renewal to allow the fish test to be conducted using semi-static renewal i.e. fresh test media prepared each 24 hours.  It should be noted that the hydrolysis study indicated that the test item was more stable at higher pH values, in line with the pH of the test medium used in the ecotox studies and this, along with the different diluents used, will explain the apparent ‘conflict’ with the hydrolysis study.  It should also be noted that the test item is a mixture of components and hence toxicity cannot be attributed to any one, or more, of the components present but to the test item as a whole.  Therefore whilst the peak measured in the ecotox studies may not reflect that of the main component it does give a ‘marker’ for confirming correct preparation of the test solutions and the use of nominal test concentrations to express the results of the test is appropriate.

Short-term toxicity to aquatic invertebrates:

The 48-Hour EC₅₀for the test material to Daphnia magna based on nominal test concentrations was 1.2 mg/l with 95% confidence limits of 0.96 - 1.5 mg/l. The No Observed Effect Concentration was 0.18 mg/l.

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to range from 94% to 117% of nominal valuewith the exception of the 0.10 mg/l test concentration at 0 hours which showed a measured concentration of 129% of nominal.  This was considered not to affect the study as this concentration was below the NOEC and all other measured concentrations were within the 80% to 120% acceptance limits.  Given thisthe results are based on nominal test concentrations only.

Short-term toxicity to aquatic algae and cyanobacteria:

The effect of the test material on the growth of Desmodesmus subspicatus has been investigated over a 72-Hour period and gave the results in the following table:

Response Variable	EC50(mg/l)	95% Confidence Limits (mg/l)			No Observed Effect Concentration (NOEC) (mg/l)	Lowest Observed Effect Concentration (LOEC) (mg/l)
Growth Rate	21	16	-	26	3.2	10
Yield	6.6	5.6	-	7.8	1.0	3.2

Analysis of the test preparations at 0 and 72 hours showed measured test concentrations range from 85% to 111% of nominal and so the results are based on nominal test concentrations only.

Short-term toxicity to microorganisms:

The effect of the test material on the respiration of activated sewage sludge gave a 3‑Hour EC₅₀of 160 mg/l. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 54 mg/l.

The reference material gave a 3-Hour EC₅₀value of 6.7 mg/l, 95% confidence limits 5.1 – 8.8 mg/l.