Benzenamine, N-phenyl-, styrenated

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is highly insoluble in water, hence indicating that aquatic toxicity is unlikely to occur

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING

According to REACH Annex VIII column 1, 9.1.3. Short-term toxicity testing on fish, the registrant may consider long-term toxicity testing instead of short-term. According to column 2, 9.1.3, the study does not need to be conducted if:
— there are mitigating factors indicating that aquatic toxicity is unlikely to occur, for instance if the substance is highly insoluble in water or the substance is unlikely to cross biological membranes, or — a long-term aquatic toxicity study on fish is available. Long-term aquatic toxicity testing as described in Annex IX shall be considered if the chemical safety assessment according to Annex I indicates the need to investigate further effects on aquatic organisms. The choice of the appropriate test(s) will depend on the results of the chemical safety assessment.
The long-term aquatic toxicity study on fish (Annex IX, Section 9.1.6) shall be considered if the substance is poorly water soluble.

In general, there is no legal limit value available defining a substance as poorly water soluble or insoluble under REACH. However, in ECHA’s Guidance document Chapter R.7b: Endpoint specific guidance Version 3.0 – February 2016, it is stated: „poorly water soluble substances (e.g. water solubility below 1 mg/L or below the detection limit of the analytical method of the test substance)“. Further, poorly soluble substances are defined by OECD (2000 OECD SERIES ON TESTING AND ASSESSMENT, Number 23, GUIDANCE DOCUMENT ON AQUATIC TOXICITY TESTING OF DIFFICULT SUBSTANCES AND MIXTURES, ENV/JM/MONO(2000)6) as substances with a limit of solubility <100 mg/l although technical problems are more likely to occur at <1mg/l as defined in TGD (1996). Very low water solubility (i.e. in the low μg/l range) could be used as a reason to significantly modify a standard test or to test non-pelagic organisms preferentially.
ECHA’s Guidance document Chapter R.7c: Endpoint specific guidance Version 3.0 – June 2017 further says: „As indicated in the OECD TG 305, for strongly hydrophobic substances (log Kow > 5 and a water solubility below ~ 0.01-0.1 mg/L), testing via aqueous exposure may become increasingly difficult. However, an aqueous exposure test is preferred for substances that have a high log Kow but still appreciable water solubility with respect to the sensitivity of available analytical techniques, and for which the maintenance of the aqueous concentration as well as the analysis of these concentrations do not pose any constraints.
The solubility of the test item in water was determined to be 20.6 µg/l, determined based on the most soluble fraction. The additional components could not have been determined above their LOQ. Further, 9.44 µg/l was the LOQ of p-SDPA, making in case of a full and not limit test the determinations of the lower concentrations impossible. Last but not least, water solubility determination was performed in HPLC water. Ecotoxicity tests are performed in media containing various supplements and biological material, which is expected to lower the sensitivity of the analytical method. Hence, quantification of the test item up to its water solubility in ecotoxicity test media could like not be performed at all. So, the required analytics for ecotoxicity testing, both short and long-term, are technically not feasible, and testing does not need to be conducted.

Based on the available information it can be stated that, as outlined in the first waiving possibility under REACH, the substance is highly insoluble in water, and hence, aquatic toxicity is unlikely to occur. The latter conclusion is supported by available studies conducted prior to REACH implementation, i.e. each a study for toxicity against Brachydanio rerio, and studies according to EU method C.2 and OECD 209. In those studies, the EL50 was determined to be 0.92 mg/l (fish toxicity, WAF), EL50 ca. 50 mg/l (EU method C.2) and EC50 > 10 g/l (OECD 209), which are way above the possible water solubility of the registered substance. With regard to daphnids and fish, adequate information for environmental classification and labelling is available, as the noted effects were above the water solubility and trigger classification as Aquatic Chronic Cat. 4, so the second waiving criterion under REACH is also met, as the assessment of the available data does so not indicate the need to investigate further effects on aquatic organisms.

Hence, an additional study of the acute toxicity of the registered substance against fish does not need to be conducted, as it is considered both not technically feasible and no additional information on classification and labelling could be retrieved, and the study can be omitted due to animal welfare.

Reason / purpose for cross-reference:

data waiving: supporting information

Remarks:

water solubility

Reason / purpose for cross-reference:

data waiving: supporting information

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Scientifically reasonable study design similar to OECD 203 with acceptable deficiencies in documentation. Given data indicate that the study was well-performed.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

not applicable

GLP compliance:

not specified

Analytical monitoring:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: direct weighing, treatment with Ultra-Turrax for ca. 10 min.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Test item is insoluble in water, precipitates in big pearls on the bottom, smaller particles are swimming on the surface. Test solution was treated for ca. 10 minutes with Ultra-Turrax, resulting in milky appearance of the water

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

no data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no data

Test temperature:

20.8 - 22.2 °C

pH:

5.8 - 6.9

Dissolved oxygen:

3.6 - 9.6 mg/l

Nominal and measured concentrations:

Nominal: 0.1, 0.422, 0.562, 0.750, 1.0, 1.33, 1.8, 2.4, 3.16, 3.2, and 10 g/l

Details on test conditions:

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : swimming behaviour, mortality

Reference substance (positive control):

not required

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.92 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: See table on results
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: At 10 g/l, substance was not distributed equally but was concentrated on the surface, bottom and walls.

Validity criteria fulfilled:

not specified

Conclusions:

The study was conducted with a scientifically reasonable study design similar to OECD 203 on the registered substance itself with acceptable deficiencies in documentation. However, the given data indicate that the study was well performed. Hence, the results can be considered as sufficiently reliable to assess the toxicity of the test item towards Brachydanio rerio. The LC50 was calculated as 0.92 g/l (96h), which does not trigger classification as acute toxic cat. 1. according to Regulation (EC) 1272/2008. With regard to table 4.1.0(b), ‘Safety net’ classification, of the regulation, cases when data do not allow classification under the denoted criteria but there are nevertheless some grounds for concern. This includes, for example, poorly soluble substances for which no acute toxicity is recorded at levels up to the water solubility, and which are not rapidly degradable and have an experimentally determined BCF ≥ 500 (or, if absent, a log K ow ≥ 4), which will be classified in this category. So, the present study does trigger classification as aquatic chronic Cat 4.

Executive summary:

In a 96-h acute toxicity study, Brachydanio rerio were exposed to the test item at nominal concentrations of 0, 0.1, 0.422, 0.562, 0.750, 1.0, 1.33, 1.8, 2.4, 3.16, 3.2, and 10 g/l under static conditions. The 96-h LC₅₀was 0.92 g/l.

Based on the results of this study, the test item would need be classified as Aquatic chronic Cat 4 in accordance with the classification system of Regulation (EC) 1272/2008.

This toxicity study is classified as acceptable to assess short-term toxicity in fish.

Description of key information

Conduction of the study technically not feasible.