2,2'-methylenebis[6-cyclohexyl-p-cresol]

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-09-23 - 1991-09-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Remarks:

The study was conducted under GLP according to a guideline issued by the German Environmental Protection Agency (Umweltbundesamt Berlin - Letale Wirkung beim Zebrabärbling -Brachyodanio rerio- (Lethal effects on Brachydanio rerio) (LC0, LC50, LC100, 48-96h) (May 1984)) on the registered substance itself. The method is to be considered scientifically reasonable with minor deficiencies in documentation. Also, there is a notable deviation of the analytically determined concentrations (via DOC content) from the nominal ones. However, this deviation is documented and allows an adapted assessment.

Qualifier:

according to guideline

Guideline:

other: Umweltbundesamt Berlin - Letale Wirkung beim Zebrabärbling -Brachyodanio rerio- (Lethal effects on Brachydanio rerio) (LC0, LC50, LC100, 48-96h) (May 1984)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 mg/l, 125 mg/l, 177 mg/l, 250 mg/l, 354 mg/l, 500 mg/l, 707 mg/l, 1000 mg/l
- Sampling method: Daily examinations

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Weighing-in directly

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrabärbling (zebra danio)
- Strain: Brachydanio rerio HAMILTON BUCHANAN
- Source: West-Aquarium (Bad Lauterberg, Germany)
- Age at study initiation (mean and range, SD): 12 weeks
- Length at study initiation (length definition, mean, range and SD): 2.5 - 3.5 cm

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96

Hardness:

13.0 °dH

Test temperature:

21.0°C - 21.9°C

pH:

7.3 - 7.9

Dissolved oxygen:

8.1 - 9.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Aquarium 300 x 135 x 200 mm
- Material, size, headspace, fill volume: 5 L
- Aeration: vented
- No. of organisms: 10/dose

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: synthetic freshwater
- Total organic carbon: DOC <2 - 3 mg/L
- Culture medium different from test medium: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Viability (daily), length, weight (end of test)

TEST CONCENTRATIONS
- Test concentrations: 0 mg/l, 125 mg/l, 177 mg/l, 250 mg/l, 354 mg/l, 500 mg/l, 707 mg/l, 1000 mg/l

Reference substance (positive control):

not required

Duration:

72 h

Dose descriptor:

LC0

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC10

Effect conc.:

707 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: See Tables
- Observations on body length and weight: See Tables
- Mortality of control: not observed
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: After centrifugation, unsolved matter remained on the surface of the test media.

Results with reference substance (positive control):

not applicable

Validity criteria fulfilled:

yes

Remarks:

performance according to guideline without deviation

Conclusions:

The study was conducted under GLP according to a guideline issued by the German Environmental Protection Agency (Umweltbundesamt Berlin - Letale Wirkung beim Zebrabärbling -Brachyodanio rerio- (Lethal effects on Brachydanio rerio) (LC0, LC50, LC100, 48-96h) (May 1984)) on the registered substance itself. The method is to be considered scientifically reasonable with minor deficiencies in documentation. Hence, the results can be considered as reliable to assess the effects of Phenol, 2,2'-methylenebis-(6-cyclohexyl-4-methyl) to aquatic organisms, here, zebra danio. Taking into account the determined effect values after 96h, based on nominal concentrations, i.e. LC0 = 500 mg/L, LC10 = 707 mg/L, and LC50 > 1000 mg/L, the test item does not need to be classified as hazardous to the aquatic environment according to Regulation (EC) No. 1272/2008, neither acute nor long-term.
A substance-specific analysis and hence specific verification of the actual concentrations was not performed. As already mentioned, via DOC analysis the solved fraction of the test item as well as possible metabolites were determined. These DOC values were at concentrations of 250 – 500 mg/L and 1000 mg/L determined to be 0 mg/L. At nominal concentration of 125 and 177 mg/L the DOC values were 0 and 1 mg/L (≙0.8 mg/L test item). At the nominal concentration of 707 mg/L, DOC values were determined to 0 and 9 mg/L (≙11 mg/L test item). Due to these variations, the water solubility of the substance needs to be taken into account, which was determined to be 0.034 mg/L. It can be reasonably concluded that the observed variations in DOC determination were due to a possible insensitivity of the analytical method or unintentionally added compounds other than the test item. Hence, it can be assumed that the observed effects, i.e. actually the lacking of mortality, was observed at concentrations maximally as high as the substance water solubility and the actual LC50 would virtually be above the water solubility of the substance. In this case, referring to the actual concentrations, the safety net classification as aquatic chronic cat. 4 would be triggered.
In summary, on the grounds of the obtained results, Phenol, 2,2'-methylenebis-(6-cyclohexyl-4-methyl) can be classified to the category aquatic chronic cat. 4 according to Regulation (EC) No. 1272/2008, based on estimated concentrations, and would not need to be classified based on the nominal ones.

Executive summary:

In a 96-h acute toxicity study, zebra danio (Brachydanio rerio HAMILTON BUCHANAN) were exposed to Phenol, 2,2'-methylenebis-(6-cyclohexyl-4-methyl) at nominal concentrations of 0,125, 177, 250, 354, 500, 707, 1000 mg/L under static conditions. The 96-h LC₅₀was >1000 mg/L, The LC₀ = 500 mg/L, LC₁₀ = 707 mg/L. Based on the results via the nominal concentrations of this study, Phenol, 2,2'-methylenebis-(6-cyclohexyl-4-methyl) would not be classified as harmful to zebra danio in accordance with the classification system of Regulation 1272/2008. Taking into account the water solubility of the substance, classification as aquatic chronic cat. 4 is triggered.

Description of key information

Short-term toxicity to fish: LC50(96h) > 1000 mg/l for Brachydanio rerio (UBA-Vorschrift, Letale Wirkung beim Zebrabärbling, May 1984, static, GLP)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

1 000 mg/L

Additional information

The chosen endpoint is the only available study. The study was conducted under GLP according to a guideline issued by the German Environmental Protection Agency (Umweltbundesamt Berlin - Letale Wirkung beim Zebrabärbling -Brachyodanio rerio- (Lethal effects on Brachydanio rerio) (LC0, LC50, LC100, 48-96h) (May 1984)) on the registered substance itself. The method is to be considered scientifically reasonable with minor deficiencies in documentation. Hence, the results can be considered as reliable to assess the effects of Phenol, 2,2'-methylenebis-(6-cyclohexyl-4-methyl) to aquatic organisms, here, zebra danio. Taking into account the determined effect values after 96h, based on nominal concentrations, i.e. LC0 = 500 mg/L, LC10 = 707 mg/L, and LC50 > 1000 mg/L, the test item does not need to be classified as hazardous to the aquatic environment according to Regulation (EC) No. 1272/2008, neither acute nor long-term.

A substance-specific analysis and hence specific verification of the actual concentrations was not performed. Further, the water solubility of the substance needs to be taken into account, which was determined to be 0.034 mg/L. Hence, it can be assumed that the observed effects, i.e. actually the lacking of mortality, was observed at concentrations maximally as high as the substance water solubility and the actual LC50 would virtually be above the water solubility of the substance. In this case, referring to the actual concentrations, the safety net classification as aquatic chronic cat. 4 would be triggered.

In summary, on the grounds of the obtained results, Phenol, 2,2'-methylenebis-(6-cyclohexyl-4-methyl) needs to be classified to the category aquatic chronic cat. 4 according to Regulation (EC) No. 1272/2008.