Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.002 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.023 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.002 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC marine water (intermittent releases):

0.023 mg/L

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

59.9 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

59.9 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.5 mg/kg food

Assessment factor:

300

Additional information

The studies utilised in the assessment are GLP compliant studies, and have been peer reviewed and evaluated in the context of the OECD SIDS and US HP programme.

Fish:

Read across to CAS 36878 -20 -3. Study conducted to OECD test guidelines in compliance with GLP. LC50 > 10,000 mg/l. This is significantly higher than the water solubility for the substance, but is considered to be an accurate reflection of toxicity to the substance in the event of release.

Daphnia:

To address the acute toxicity to aquatic invertebrates, two saltwater toxicity tests, using mysid shrimp are available; one on the substance itself, and one on a close structural analogue. The results of these are as follows:

CAS 68921-45-9: 96-h LC50 : 2.3 mg/l (1.3-10 mg/l; 95% confidence limits). 96-h NOEC < 1.3 mg/l.  

CAS No. 36878-20-3: 96 h EC50: c = 733 mg/l ; 96-h NOEC: c = 250 mg/l (WAF).

It is noted that the preferred study to address this endpoint utilises freshwater daphnia. However, the available data on saltwater species is considered appropriate to address the requirements of Annex XI, Para 1.1.2 as follows:

1) adequacy for the purpose of classification and labelling and/or risk assessment;

The two results available are somewhat different; this is attributed to the dosing methods seen in the experiments. For the purposes of hazard assessment, the value on the substance itself it taken as appropriate, and classification and labelling is applied on this basis. This is therefore considered adequate for risk assessment.

 

2) adequate and reliable coverage of the key parameters foreseen to be investigated in the corresponding test methods referred to in Article 13(3);

The studies are GLP compliant studies, conducted to recent guidelines. The integrity and results are therefore considered appropriate and are in accordance with the recognised guidelines. There is no documented evidence that saltwater species are more sensitive than freshwater species, although the REACH guidance attributes and additional assessment factor of 10 for risk characterisation calculations.

 

3) exposure duration comparable to or longer than the corresponding test methods referred to in Article 13(3) if exposure duration is a relevant parameter; and

The exposure duration of the study is in accordance with the guideline method at 96 hours. This is longer than the required 48 hour exposure utilised in the acute toxicity to Daphnia study.

 

4) adequate and reliable documentation of the study is provided.

 

The studies are GLP compliant studies, and have been peer reviewed and evaluated in the context of the OECD SIDS and US HP programme. The results are presented as appropriate summaries of the original reports.

 

The use of these studies results in classification and labelling under the CLP Regulation (EC) No 1272/2008 as follows:

 

Aquatic Chronic Category 2

 

H411: Toxic to aquatic life with long lasting effects.

 

A Daphnia magna reproduction test is available for read-across substance, CAS 10081-67-1. In this study, there were no significant treatment-related effects on survival, reproduction or growth at concentrations ≤38 μg a.i./L. Consequently, the NOEC for reproduction was 38 μg a.i./L and the LOEC was >38 μg a.i./L; these values are welll below the water solubility of the read-across substance ( < 0.0067 mg/L) and also well below the water solubility of this substance (0.706 mg/L)

 

Algae:

Read across to supporting substance CAS 36878 -20 -3. EC50 = 650 mg/l; NOEC 33 mg/l. Effects were determined to be algistatic based on the rapid re-growth of an aliquot of cells taken from 500 mg/L cultured in fresh control media. However the results do not trigger classification and labelling under the CLP Regulation.

The substance has been supported under Environmental Protection Agency’s (EPA’s) High Production Volume (HPV) Challenge Program. The American Chemical Councils RAPA Panel, has derived a “Substituted Diphenylamines” category of chemicals for this substance, please refer to EPA reference 201-14700A located at http://www.epa.gov/hpv/pubs/summaries/subdipha/c13378rt.pdf

 

Relying on several factors specified in EPA’s guidance document on “Development of Chemical Categories in the HPV Challenge Program,” in which use of chemical categories is encouraged, the chemicals constitute a chemical category on the following basis:

 

Structural Similarity. A key factor supporting the classification of these chemicals as a category is their structural similarity (see Figure 1). All share a common starting material; Diphenylamine (Benzenamine, N-phenyl-, CAS# 122-39-4), a common synthetic pathway, and all compounds in this category are diamines with various substitutions.

 

Similarity of Physicochemical Properties. The similarity of the physicochemical properties of these materials parallels their structural similarity. All are off-white to light brown solids or viscous liquids intended for use as antioxidants in finished rubber articles or as antidegradant additives that extend the useful life of heavy-duty industrial functional fluids used in high-speed, high-temperature and/or high-load applications. As a class, these amine-based antidegradant compounds are less migratory (more polymer-bound) and less staining than the Substituted p-Phenylenediamine antidegradants. The use of these materials requires that they be stable under high temperatures. Their low volatility is due to their low vapor pressure, highly viscous or solid form. The existing information for these materials indicates that they have low water solubility and high flash points.

 

Fate and Transport Characteristics. Members of this category have been shown to be not readily biodegradable, so additional testing is not needed. The lack of water solubility of the members of this category makes hydrolysis testing unnecessary. These materials have been shown not to partition to water or air if released into the environment due to their low water solubility and low vapor pressure.

 

Toxicological Similarity. Review of existing published and unpublished test data for Substituted Diphenylamines shows the aquatic and mammalian toxicity among the materials within this category are similar.

 

Aquatic Toxicology. Data on acute fish toxicity, acute invertebrate toxicity, and alga toxicity were reviewed. With increasing molecular weight, the toxicity to aquatic organisms decreases. These materials have high estimated log K_owvalues, such that acute toxicity is not expected at or below their low levels of water solubility. For the purposes of the HPV Program, additional testing was not proposed for the members of this category.

 

Conclusion. Based upon the data reviewed in “Substituted Diphenylamines” category of chemicals, the physicochemical and toxicological properties of the Substituted Diphenylamine category members are similar and follow a regular pattern as a result of that structural similarity. Therefore, the definition of a chemical category has been met, and read across is considered appropriate for the category of chemical.

Conclusion on classification

The use of these studies results in classification and labelling under the CLP-Regulation (EC) No 1272/2008 as follows:

Aquatic Chronic Category 2

H411: Toxic to aquatic life with long lasting effects.