tert-butyl peroxypivalate

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

fish early-life stage toxicity

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 as technically not feasible. REACH Regulation No. 1907/2006, Annex XI, Sect. 2, states that studies can be omitted based on their intrinsic properties which can lead to the non-feasibility of the required study.

Due to the unstable nature of organic peroxides, it can be assumed that upon contact with water and organic matter, tert-butyl peroxypivalate undergoes rapid degradation resulting in the formation of respective alcohols and acids. Therefore, tert-butyl peroxypivalate is considered to be not stable in aquatic environment. The performance of a test for the assessment of long-term toxicity to fish was considered as technically not feasible. For detailed explanation, please to the following paragraphs:

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.

Furthermore, 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 technically not feasible since the test item is not stable in the aquatic environment and long-term exposure to aquatic animals is not expected.

The 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) they are considered to be intermediates and 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 technically not feasible due to the instabile nature of the organic peroxide and its intrinsic properties. To cover the endpoint of long-term toxicity to fish a QSAR estimation was performed with Ecosar v2.2 and included in the dossier as a supporting study record.

Reference 2

Endpoint:

adult fish: sub(lethal) effects

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

2022

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

Please refer to the attached QMRF and QPRF documents.

Qualifier:

according to guideline

Guideline:

other:

Version / remarks:

REACH guidance on QSAR R.6

Principles of method if other than guideline:

Calculation of Long-Term toxicity in fish. Software used: ECOSAR 2.2 (stand-alone version) for chemical class "Peroxyester" and "Neutral Organic SAR (Baseline Toxicity)"

GLP compliance:

no

Specific details on test material used for the study:

SMILES: CC(C)(C)OOC(=O)CC(C)CC(C)(C)C

Analytical monitoring:

not required

Test organisms (species):

other: fish

Water media type:

freshwater

Total exposure duration:

30 d

Remarks on exposure duration:

chronic exposure

Key result

Duration:

30 d

Effect conc.:

0.874 mg/L

Remarks on result:

ChV (chronic value, QSAR)

Remarks:

The substance is within the applicability domain of the model. ECOSAR class "Peroxyester".

Key result

Duration:

30 d

Effect conc.:

1.41 mg/L

Remarks on result:

ChV (chronic value, QSAR)

Remarks:

The substance is within the applicability domain of the model. ECOSAR class "Neutral Organic SAR (Baseline Toxicity)".

 

ECOSAR v2.2 Class-specific Estimations
ECOSAR Class	Organism	Duration	End Pt	Predicted mg/L (ppm)
Peroxy Esters	Fish	96-hr	LC50	9.01
Peroxy Esters	Daphnid	48-hr	LC50	47.9
Peroxy Esters	Green Algae	96-hr	EC50	0.286
Peroxy Esters	Fish		ChV	0.874 *
Peroxy Esters	Daphnid		ChV	1.65
Peroxy Esters	Green Algae		ChV	0.06

 * = The toxicity value was estimated through application of acute-to-chronic ratios per methods outlined in the ECOSAR Methodology Document provided in the ECOSAR Help Menu.

Validity criteria fulfilled:

yes

Conclusions:

Using ECOSAR v2.2 the long-term toxicity ChV value for fish was calculated to be 0.874 mg/L. The substance is within the applicability domain of the model.

Executive summary:

The long-term toxicity in fish was calculated using ECOSARv 2.2 as a stand-alone program from US Environmental Protection Agency.

The adequacy of a prediction depends on the following conditions:

a) the (Q)SAR model is scientifically valid: the scientific validity is established according to the OECD principles for (Q)SAR validation;

b) the (Q)SAR model is applicable to the query chemical: a (Q)SAR is applicable if the query chemical falls within the defined applicability domain of the model;

c) the (Q)SAR result is reliable: a valid (Q)SAR that is applied to a chemical falling within its applicability domain provides a reliable result;

d) the (Q)SAR model is relevant for the regulatory purpose.

 

For assessment and justification of these 4 requirements the QMRF and QPRF files were developed and attached to this study record.

 

Description of the prediction Model

The prediction model was descriped using the harmonised template for summarising and reporting key information on (Q)SAR models. For more details please refer to the attached QSAR Model Reporting Format (QMRF) file. 

 

Assessment of estimation domain

The assessment of the estimation domain was documented in the QSAR Prediction Reporting Format file (QPRF). Please refer to the attached document for the details of the prediction and the assessment of the estimation domain.

Description of key information

The performance of a test for long-term toxicity to fish is considered as technically not feasible. REACH Regulation No. 1907/2006, Annex XI, Sect. 2, states that studies can be omitted based on their intrinsic properties which can lead to the non-feasibility of the required study.

Due to the unstable nature of organic peroxides, it can be assumed that upon contact with water and organic matter, tert-butyl peroxypivalate undergoes rapid degradation resulting in the formation of respective alcohols and acids. Therefore, tert-butyl peroxypivalate is considered to be not stable in aquatic environment. The performance of a test for the assessment of long-term toxicity to fish was considered as technically not feasible.