2-Butanone, peroxide

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Data waiving:

other justification

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.”
REACH Regulation No. 1907/2006, Annex XI, Sect. 1.1 states that the study requirements can be covered with existing data and based on weight of evidence.
Below is listed the existing data in a weight of evidence approach why the test for long-term toxicity to Daphnia with the registered substance is scientifically not justified:
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:
Organic peroxides 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, the test item 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.

In a series of short-term toxicity tests to aquatic organisms was determined that the most sensitive specie was the green algae with an EC50 of 5.6 mg/L, which effect level is several magnitudes lower than the L(E)C50 for fish and Daphnia. Therefore, lower effect levels in the long-term toxicity studies with invertebrates are not anticipated.

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 OECD ESD No. 3: Plastic additives), 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.

In summary, long-term toxicity testing in an invertebrate species is considered not scientifically justified according to REACH Regulation No. 1907/2006, Annex IX, Sect. 9.1., Col. 2 and Annex XI, Sect. 1.

Description of key information

The performance of a test for long-term toxicity to aquatic invertebrates (Daphnia sp.) is scientifically unjustified.

REACh Regulation No. 1907/2006, Annex IX, Sect. 9.1., Col. 2, states as follows:

“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 choice of the appropriate test(s) depends on the results of the chemical safety assessment.”

The chemical saftey assessment does not indicate the need to further investigate effects on aquatic organisms.

1) Methyl-ethylketone peroxide is hardly soluble in water.

2) Methyl-ethylketone peroxide is readily biodegradable.

3) Bioaccumulation potential was determined to be low. The bioaccumulation factor (BCF) was calculated to be 3.2 and 9.7 L/kg (monomer and dimer, respectively).

4) Direct and indirect exposure of the water compartment is highly unlikely.

For more details on exposure assessment see risk assessment report in section 13.

In summary, long-term toxicity testing to aquatic invertebrates is not necessary.