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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

One short-term result on fish toxicity is available for the bis(4-tert-butylcyclohexyl) peroxydicarbonate. The 96-h LC50 was determined to be 704 mg/L. Although this result is considered to be of limited reliability no repeat test was conducted as the endpoints "short-term toxicity testing on invertebrates" and "growth inhibition study aquatic plants" are more sensitive and therefore critical for classification and labelling as well as for the risk assessment.

Key value for chemical safety assessment

LC50 for freshwater fish:
704 mg/L

Additional information

One experimental result (reliability Klimisch 3) is available for the endpoint acute toxicity to fish. In the 96-h acute toxicity study according to OECD guideline 203, approximately 3 month old rainbow trout (Oncorhynchus mykiss) were exposed to bis(4-tert-butylcyclohexyl) peroxydicarbonate at nominal concentrations of 0 (control and solvent control),100, 180, 320, 560 and 1000mg/L under semi-static conditions.

The 96-h LC50was calculated to be 704 mg/L. The NOEC value (based on mortality) was 320 mg/L. Sublethal effects of darkened pigmentation were observed in three fish of the groups exposed to 1000 mg/L of test substance.

However, the study is deemed to be unreliable as the test design shows significant methodological deficiencies. Undissolved test material could be observed in the test vessels which could have been taken up by the test organisms by ingestion. In addition, the actual test substance concentrations were not measured so that the actual exposure concentrations are not known.

However, fish are typically the least sensitive species against organic peroxides (cf. position paper attached to IUCLID section 13) an additional vertebrate study for this endpoint is considered to be unnecessary.

The results of the existing acute toxicity study in fish study are deemed adequate for classification purposes. The requirements for classification and labelling, i.e. availability of results for trophic levels, are fulfilled. The results on short-term toxicity in invertebrates and growth inhibition to aquatic plants are more sensitive compared to the acute toxicity in fish and are therefore critical for classification and labelling as well as for the risk assessment. Thus, particularly taking into account animal welfare considerations, a repeat study to obtain new data on the short-term toxicity on fish is deemed unnecessary.