tert-butyl 2-ethylperoxyhexanoate

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

adult fish: sub(lethal) effects

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

The performance of a test for long-term toxicity to fish is considered not scientifically justified. REACH Regulation No. 1907/2006, Annex IX, Sect. 9.1., Col. 2, states that:
“9.1.: Long-term toxicity testing shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on aquatic organisms.”

The chemical safety assessment does not indicate the need to further investigate the effects on aquatic organisms for the following reasons:

Exposure and stability considerations:
Substances of the peroxyester group are not stable in the aquatic environment. Due to the unstable nature of organic peroxides, it can be assumed that upon contact with water and organic matter, the substances undergo degradation resulting in the formation of respective alcohols and acids. Therefore, an abiotic degradation of the substances in the environment is expected.
In addition, peroxyesters were found to be non-persistent. The test item itself was shown to be readily biodegradable.

Further it is not expected to have potential for bioaccumulation (calculated BCF << 2000 L/kg). Please also refer to IUCLID Section 5.3.1.
Consequently, long-term toxicity testing is considered scientifically not justified since the test item is not stable in the aquatic environment and long-term exposure to aquatic animals is not expected.

Further, Environmental Risk Assessment reveals safe use of the substance throughout its whole life cycle due to very low exposure of the water compartment which is especially based on the following facts:

Organic peroxides, when released into the sewage of a manufacturing or a downstream user plant, are treated with other substances in dedicated sewage treatment plants. The activated sludge from these sewage treatment plants is then removed and treated as chemical waste. From the production plant, the release of organic peroxide into the sewage is very limited, not to say negligible. The waste water from production plant can be treated on site (at least a physical/chemical treatment, which will decompose organic peroxides by chemical reaction), which is usually followed by a biological treatment. Regarding industrial end-uses, organic peroxides are mainly used as cross-linking agent/polymerization initiator for the production of resins/rubbers/polymers. Based upon the fact that organic peroxides are totally consumed during the process (>99%, which is confirmed by the release factor to sewage for curing agents from ESD n°3), the surface water is not exposed to organic peroxides via the waste water system. As a consequence, the surface water is not considered to be significantly exposed by the organic peroxide.

Thus, the environmental Risk Assessment does not indicate a need for an additional long-term aquatic test. Risk assessment is based on the long-term daphnia study.

In summary, long-term toxicity testing in a vertebrate species is considered not scientifically justified according to REACH Regulation No. 1907/2006, Annex IX, Sect. 9.1., Col. 2 and not in line with animal welfare.

Additional information

The performance of a test for long-term toxicity to fish is considered not scientifically justified. REACH Regulation No. 1907/2006, Annex IX, Sect. 9.1., Col. 2, states that: “9.1.: Long-term toxicity testing shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on aquatic organisms.”  

The chemical safety assessment does not indicate the need to further investigate the effects on aquatic organisms based on exposure and stability considerations.

1) TBPEH is readily biodegradable. Further, exposure to the water compartment is considered to be unlikely

2) The bioaccumulation factor (BCF) for TBPEH was calculated to be 672 L/kg (log BCF = 2.827). Thus, no significant bioaccumulation is expected to occur. The BCF value determined indicates no significant bioaccumulation potential.

In summary, long term toxicity testing was considered not scientifically justified and not in line with animal welfare.