O-(2-ethylhexyl) O,O-tert-pentyl peroxycarbonate

Endpoint summary

Additional information

Several aquatic studies have been performed:

- The acute toxicity to fish is read across from CAS 34443 -12 -4 for which an OECD 203 is available showing no toxicity up to the water solubility. This is confirmed by an OECD 236 with the test chemical. Both test show an LC50 > 100 mg/L loading.

- The acute toxicity of the test chemical to Daphnia Magna prepared as a Water Accommodated Fraction (WAF) was determined according to OECD 202 in a semi-static system over an exposure period of 48 hours at a loading concentration of 100 mg/L. The EL50 (48h) was > 100 mg/L (Loading).

The test substance was concluded as not acutely toxic to Daphnia at its solubility limit in the test media.

- The toxicity of the test chemical to an exponentially growing culture of P. subcapitata was determined as a Water Accommodated Fraction (WAF)

over an exposure period of 72 hours. NOELR may be expressed (for the test material as a whole) as 92.2 and EL50 as >944.1 mg/L. Alternatively when considering the parent chemical only it may be considered as non toxic to algae at its maximum achievable concentration in test medium.

- Toxicity to microorganisms was determined as well in an activated sludge respiration inhibition test was performed according to OECD 209.

The EC50 (3h) of the substance for activated sludge is > 1280 mg/L. The substance is therefore considered harmless to activated sludge.

Considering the ready biodegradability, fast hydrolysis, lack of toxicity the test substance and low water solubility the substance is not expected to present an acute or chronic hazard to the aquatic environment.

The registered substance, O-(2 -ethylhexyl) O,O-tert-pentyl peroxycarbonate hydrolyzed into 2-ethylhexanol (CAS 104 -76 -7), tert amyl alcohol (CAS 75 -85 -4), Acetone (CAS 67-64-1) and Ethanol (CAS 64-17-5). These degradation products are readily soluble in water and have a low log Kow and will therefore be more bioavailable to aquatic species than the parent substance which has a low water solubility (< 1 mg/L).

Aquatic toxicity of the main degradation products is as follows:

 

2 -ethylhexanol

Endpoint	Organism	Value* [mg/L]	ECOSAR [mg/L]
96 hr LC50	fish	17.1	23.55
96 hr LC50	fish	28.2
48 hr EC50	crustacea	39	14.31
72 h EC50	algae	EbC50:11.5 ErC50: 16.6	14.09

* ECHA disseminated dossier CAS 104 -76 -7 (17 Sept. 2018)

t-amyl alcohol

Endpoint	Organism	Value* [mg/L]	ECOSAR [mg/L]
96 hr LC50	fish	2430	362.6
48 hr EC50	crustacea	540	191.6
72 h EC50	algae	ErC50: >500	106.0

* ECHA disseminated dossier CAS 75 -84 -4 (17 Sept. 2018)

2 -Ethylhexanol is the more toxic substance according to the predictions by ECOSAR which are in line with the data presented in the ECHA disemmitated dossiers. This substance will therefore be used in the risk assessment of O-(2 -ethylhexyl) O,O-tert-pentyl peroxycarbonate.