Reaction mass of 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-inden-5-yl isobutyrate and 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-inden-6-yl isobutyrate

Short-term toxicity to fish

Description of key information

For assessing the acute fish toxicity of Cyclabute information from Cyclobutanate is used. The read across documentation can be found in the Aquatic toxicity Endpoint summary. The executive summary of the acute fish toxicity with Cyclobutanate and Cyclaprop are presented below.

Acute fish toxicity with Cyclobutanate

Cyclabute has an isobutyl group attached to the ester, while Cyclobutanate has a straight chain alkyl ester (see for further read across documentation the Endpoint summary). The acute toxicity of Cyclobutanate towards Oncorhynchus mykiss was investigated according to OECD guideline 203 under GLP. Fish were exposed to time-weighted average mean measured concentrations of 0.85, 1.4, 2.7, 4.9 and 11.0 mg/l and observed for 96 hours in a semi-static test setup. The test material solutions were prepared by stirring an excess (100 mg/l) of test material in dechlorinated tap water for a period of 48 hours prior to removing any undissolved test material by filtration (0.2 µm). This "saturated" solution was then further diluted, as necessary, to provide the remaining test groups. Sub-lethal effects of exposure were observed at the time-weighted mean measured test concentrations of 2.7, 4.9 and 11.0 mg/1. At the time-weighted mean measured test concentration of 4.9 mg/1 between 24 and 48 hours 7 fish were observed to be moribund. At the time-weighted mean measured test concentration of 11.0 mg/1 after 1.5 hours all 10 fish were observed to be moribund. A steep dose-response curve was visible. A decline in measured test concentrations was shown despite the use of sealed vessels with minimal headspace and no aeration in an attempt to minimise losses due to the volatile nature of the test material. Given the decline in the measured test concentrations (10 -70% loss was seen in 24 hours) it was considered justifiable to base the results of the definitive test on the time-weighted mean measured test concentrations in order to give a "worst case" analysis of the data. The 96-Hour LC50 based on the time-weighted mean measured test concentrations was 3.6 mg/1 with 95% confidence limits of 2.7- 4.9 mg/1 (concentrations resulting in 0% and 100% mortality respectively).

Acute fish toxicity with Cyclaprop

The acute toxicity of Cyclaprop towards Pimephales promelas was investigated according to OECD guideline 203 under GLP. Fish were exposed to nominal concentrations of 2.4, 5.3, 12, 25 and 56 mg/l under flow-through conditions and observed for 96 hours. Based on mean measured concentrations, the 96h-LC50 was found to be 6.7 mg/l. The test concentrations where oily-slick was observed coincide with the concentrations at which mortality was found. Physical hindrance may therefore have contributed to the effects found. It is however, difficult to make a distinction between physical and systemic effects and therefore as a worst case approach the mortality is assumed to result from systemic toxicity.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

3.6 mg/L