1-methyl-1-phenylethyl peroxyneodecanoate

Endpoint summary

Description of key information

Three trophic levels (fish, daphnia, algae) are covered by the acute toxicity data set. No chronic data are available.

Daphnia magna Straus was observed to be the most sensitive species. The related 48-hr EC50 was determined in a short-term toxicity study according to method C.2 of the European Directive 92/69/EEC which is in conformity with the OECD guideline 202 (part I) and under GLP with 4.9 mg/L. Since the parent substance was quantified via its degradation product neodecanoic acid, the derived 48-hr EC50 for 1-methyl-1-phenylethyl peroxyneodecanoate is 3.8 mg/L.

Additional information

The test item 1-methyl-1-phenylethyl peroxyneodecanoate in isododecane is a mixture of 2 constituents with different solubilities and physico­chemical properties. Therefore, test solutions were prepared according to the WAF methodology (water accommodated fraction) described by OECD. Since 1-methyl-1-phenylethyl peroxyneodecanoate in isododecane is not stable in water, the parent substance was quantified in most of the reported tests via its degradation product neodecanoic acid.

Test results on the acute toxicity of 1-methyl-1-phenylethyl peroxyneodecanoate for three trophic levels (fish, Daphnia and alge) are available:

Fish:

Schwartz, 2018: In a 96-h acute toxicity study according to OECD 203 (17 July 1992), zebra fish (Danio rerio) were exposed to 1-methyl-1-phenylethyl peroxyneodecanoate in isododecane at nominal concentrations of 0.0 (control) and 5 mg/L under semi-static conditions. As no effect on the test organisms was observable, no statistical data evaluation was performed. LOEC: > 1.15 mg/L; NOEC: ≥ 1.15 mg/L .

Invertebrates:

Thiébaud & Kae, 2001: The 48–hr-acute toxicity of 1-methyl-1-phenylethyl peroxyneodecanoate in isododecane to Daphnia magna Straus was studied under semi-static conditions according to method C.2 of the European Directive 92/69/EEC which is in conformity with the OECD guideline 202 (part I). Daphnids were exposed to a control containing no test substance, and to WAF of respectively 3.9; 7.5; 16; 33 and 70.4 mg/L of 1-methyl-1-phenylethyl peroxyneodecanoate in isododecan for 48 hr. The 48-hr EL50 was determined to be 4.6 mg/L. Since the parent substance was quantified via its degradation product neodecanoic acid, the related 48-hr EC50 of 4.6 mg/L was converted for 1-methyl-1-phenylethyl peroxyneodecanoate. The converted EC50 used for registration of pure 1-methyl-1-phenylethyl peroxyneodecanoate was determined to be 3.8 mg/L.

Algae:

Thiébaud & Kae, 2001: In a 72–hr acute toxicity study, the cultures of freshwater algae Pseudokirchneriella subcapitata were exposed to 1-methyl-1-phenylethyl peroxyneodecanoate in isododecane at nominal concentrations of 9.9, 17.3, 30.9, 55.9, 100 mg/L under static conditions in accordance with the method C.3 described in Directive 92/69/EEC of the European Commission and in the guideline 201 of the OECD. For Pseudokirchneriella subcapitata, an ErL50 value (based on growth rate) of > 100 mg/L was determined. The NOEL was found to be > 100 mg/L. No effect on the test organisms was observable.

Microorganisms:

A respiration inhibition test with activated sludge according OECD guideline 209 was conducted by L´Haridon (2000) to determine the toxicity of 1-methyl-1-phenylethyl peroxyneodecanoate (70% in isododecane) towards microorganisms. The 3-hr EC50 of the test item for activated sludge is > 20 mg/L. This result can be used for the registration of pure 1-methyl-1-phenylethyl peroxyneodecanoate after backcaluclation to the content of 1-methyl-1-phenylethyl peroxyneodecanoate in isododecane. In conclusion, the NOEC for pure

1-methyl-1-phenylethyl peroxyneodecanoate is 14 mg/L.