4-(1-methoxy-1-methylethyl)-1-methylcyclohexene

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:

From 27 February 2006 to 26 March 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 62 mg/L and 80 mg/L (abiotic test medium solutions)
- Sampling method: Analysis of test element was performed in the test solutions "test medium control" at t= 0 and t=24h (before the first renewal).
- Sample storage conditions before analysis: at 4 ±2°C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: direct introduction of the test substance in each aquarium and addition of test medium in order to get a 2.5 L test solution.
- Eluate: none
- Differential loading: 28 mg/L, 36 mg/L, 47 mg/L, 62 mg/L, 80 mg/L
- Controls: test medium control
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Danio rerio
- Source: HB developpement élevage, La Fond Garel, 69490 St Forgeux.
- Length at study initiation (length definition, mean, range and SD): 25 to 30 mm
- Feeding during test: none

ACCLIMATION
- Acclimation period: 12 days
- Acclimation conditions (same as test or not): same
- Type and amount of food: no data
- Feeding frequency: no data
- Health during acclimation (any mortality observed): no data

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

none

Hardness:

270 mg/L (as CaCO3)

Test temperature:

23.2 to 25 °C

pH:

7.2 to 7.9

Dissolved oxygen:

78 to 98%

Salinity:

non relevant

Nominal and measured concentrations:

Nominal: 28 mg/L, 36 mg/L, 47 mg/L, 62 mg/L, 80 mg/L
Measured:
- for the 62 mg/L solution: at t= 0, 44.0% which corresponds to 62.5 mg/L when compared to the 100 mg/L solution reference
at t = 24h, 41.3 % which corresponds to 58.66 mg/L
- for the 80 mg/L solution: at t= 0, 54.6% which corresponds to 77.55 mg/L when compared to the 100 mg/L solution reference
at t = 24h, 50.4 % which corresponds to 71.59 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: all-glass vessel
- Type: open
- Material, size, headspace, fill volume: glass, 15 cm*15cm*20 cm, contains 2.5 liters
- Aeration: no data
- Renewal rate of test solution (frequency/flow rate): 24h
- No. of organisms per vessel: 7
- Biomass loading rate: 0.9 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: theoritical composition 294.0 mg/L CaCl2, 2 H20, 123.3 mg/L MgSO4, 7 H2O, 63.0 mg/L NaHCO3, 5.5 mg/L KCl
- Total organic carbon: 0.02 mg/L
- Intervals of water quality measurement: 24 h

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 14h light /10 h dark
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
every 24h , the following parameters were checked: pH, dissolved oxygen, and temperature

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 62 - < 80 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: fish at concentration 62 mg/L showed abnormal behaviour , they stayed on the side, at the bottom of the aquarium and showed a shortness of breath.
- Observations on body length and weight: no data
- Other biological observations: no data
- Mortality of control: none
- Other adverse effects control: none reported
- Abnormal responses: none reported
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: no

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Mortality:
- LC50: 227 mg/L

Sublethal observations / clinical signs:

Table 6.1.1 -01: cumulated dead fish as a function of exposure time and concentration

Nominal concentration of test substance	Fish number at the beginning of the test	Cumulated number of dead fish at each observation time
		6h	24h	48h	72h	96h
Control	7	0	0	0	0	0
28 mg/L	7	0	0	0	0	0
36 mg/L	7	0	0	0	0	0
47 mg/L	7	0	0	0	0	0
62 mg/L	7	0	0	0	0	0
80 mg/L	7	6	7	7	7	7

Table 6.1.1 -02 TOC analysis in the control medium solutions, 62 mg/L and 80 mg/L at the beginning (T =0) and at the fisrt renewal ( T= 24h)

Test solution	TOC at T = 0h	TOC at T= 24h
Control fish test medium	0.02	0.09
62 mg/L	44.0	41.3
80 mg/L	54.6	50.4

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test the 96h LC50 of Terpineol multi on Danio Rerio fish was measured to be between 62 and 80 mg/L.

Executive summary:

In a 96-h acute toxicity study, Danio rerio fish were exposed to Terpineol at concentrations of 0 (test medium control), 28, 36, 47, 62 and 80 mg/L under semi-static conditions. The 96-h LC50 was between 62 and 80 mg/L. Sublethal effects were observed at the concentration of 62 mg terpneol mix/L: abnormal behaviour, the fish stayed on the side, at the bottom of the aquarium and showed a shortness of breath. At 80 mg/l 100% mortality was seen. For estimating the LC50 the geometric mean between 62 and 80 mg/l is used = 70 mg/l.

Description of key information

Orange Flower Ether Acute fish toxicity (based on read across from Terpineol multi): 12.4 mg/l.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

12.4 mg/L

Additional information

The information on Orange Flower Ether is derived from Terpineol-multi and result in an LC50 for fish of 12.4 mg/l. The Terpineol-multi value is divided by five as this is the conservative difference between the algae and Daphnia information which information is available both for Orange Flower Ether and Terpineol_multi.

Test information on Terpineol_multi: In the Terpineol study, groups of 7 zebrafish (D. rerio) were exposed to nominal test concentrations of 0 (control), 28, 36, 47, 62 and 80 mg/L for 96 hours under semi-static conditions (renewal of test solutions every 24 hours). The nominal concentrations of 62 and 80 mg/L were analytical verified at at t= 0 and t=24h (before the first renewal). As measured concentrations remained within ±20% of nominal concentrations, effect values are expressed as nominal concentrations. Observations for mortalities and symptoms of toxicity were made at 6, 24, 48, 72 and 96 hours after exposure. All fish died within a day at the highest tested concentration of 80 mg/L. No deaths were seen throughout the test at any of the lower tested concentrations. Based on these findings the 96 -h LC50 value for Terpineol was determined to lie between 62-80 mg/L with a geometric mean value of 70 mg/L.

Fish toxicity of Orange Flower Ether (CAS #14576-08-0) using read across from Terpineol-multi (CAS #8000-41-7).

Introduction and hypothesis for the analogue approach

Orange Flower Ether is an ether attached to a cyclohexyl ring with one double bond with a methyl-group attached at the para-position. For this substance no repeated dose toxicity data are available. In accordance with Article 13 of REACH, lacking information can be generated whenever possible by mean other than vertebrate animals test, i.e. applying alternative methods such as in vitro tests, QSARs, grouping and read-across.For adequate assessment of the aquatic toxicity potential of Orange Flower Ether, read-across is performed to the close structural analogue Terpineol-multi (CAS #8000-41-7).

Hypothesis: Orange Flower Ether has similar aquatic toxicity potential as Terpineol-multi, becauseboth substances belong to the class of neutral organics for which a substances’ octanol-water partitioning coefficients (log Kow) is considered to give direct indication of its toxicity.

Available information: Experimental data on short-term toxicity to aquatic invertebrates and aquatic algae are available for both Orange Flower Ether and Terpineol-multi. Experimental fish short-term toxicity data are available only for the source chemical Terpineol-multi. For both substances short-term effect values for algae and Daphnia were determined to be in the range of 10-100 mg/L. The values for Orange Flower Ether are a factor of ca. 3-5 lower than that of Terpineol-multi

In more detail:studies with aquatic invertebrates were performed according to OECD TG 202 and in compliance with GLP criteria for both Orange Flower Ether (IFF, 2015) and Terpineol –multi (Action PIN, DRT, 2006). The 48-h EC50 values in Daphnia magna are 15 mg/L and 73 mg/L, respectively for Orange Flower Ether and Terpineol-multi. The data are reliable without restrictions (Klimisch 1).

Studies with aquatic algae were performed according to OECD TG 201 and in compliance with GLP criteria for both Orange Flower Ether (IFF, 2015) and Terpineol-multi (DRT, 2010). The 72-h ErC50 values in Pseudokirchneriella subcapitata are 26 mg/L in and 68 mg/L, respectively for Orange Flower Ether and Terpineol-multi. The data are reliable without restrictions (Klimisch 1).

Finally, a study with fish is available only for Terpineol-multi. This study was performed according to OECD 203 and in compliance with GLP criteria (ACTION PIN, 2006). The 96-h LC50 value is 62-80 mg/L in zebrafish (D. rerio). The data are reliable without restrictions (Klimisch 1).

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical are shown in the data matrix, including physico-chemical properties and available ecotoxicological information.

Purity / Impurities

Orange Flower Ether is a mono-constituent and contains impurities with the functional group, the ether bond, is absent or at another spot in the structure. This is similar to Terpineol-multi in which the functional group, the alcohol can be absent or at a different spot in the structure. Therefore it is not expected that the impurities of the source and target chemicals affect the read-across justification.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group.

In accordance with ECHA guidance (2015, RAAF) Terpineol-multi was selected because it is the most similar substance for which fish toxicity information was available.

Structural similarities and differences:

Terpineol-multi is a multi-constituent containing mostly Terpineol -alpha.Orange Flower Ether (target) and the structural analogue Terpineol –multi (source) have a cyclohexyl ring with one double bond and a methyl-group attached to the para-position. The difference between Orange Flower Ether and Terpineol-multi is an additional methyl-group bound at the functional group, making it an ether instead of an alcohol.

Bioavailability:To assess the difference in bioavailability between the target substance Orange Flower Ether and the source substance Terpineol-multi, the available experimental data for aquatic invertebrates and aquatic algae is compared. It can be seen that for Terpineol-multi, for both trophic levels, the (L)EC50 is about 70 mg/L and no significant difference in sensitivity is observed. Comparison of Daphnia EC50 values for Terpineol-multi and Orange Flower Ether results in a factor 5 lower EC50 value for Orange Flower Ether. For algae this factor is ca 3. The factor of 5 will also be used for fish as a worst case approach. Using the lower value of 62 mg/L from the Terpineol –multi fish study (conservatively), this results in a LC50 value of 12.4 mg/L for Orange Flower Ether.

Uncertainty of the prediction:There is no uncertainty in the prediction because the read across is supported with, and based on, experimental data on Orange Flower Ether from two other trophic levels (aquatic invertebrates and aquatic algae). There are no real species differences observed in the toxicity tests with Terpineol-multi and not in the tests with Orange Flower Ether, which is expected for neutral organics. As read-across is performed based on a factor difference resulting from direct comparison of existing data, no correction for molecular and/or bioavailability (i.e. log Kow) needs to be performed. Using the ECHA guidance (2015, RAAF) criteria the read across would receive a score of 5.

Data matrix

The relevant information on physico-chemical properties and aquatic toxicity are presented in the Data Matrix.

Conclusions for hazard assessment, environmental classification, PBT assessment and PNEC derivation

Hazard: the lowest short-term effect value for Orange Flower Ether is the 96-h LC50 of 12.4 mg/L as derived from read-across to the fish study available for Terpineol-multi. As long-term data are available only for aquatic algae, the value of 12.4 mg/L will be used directly for derivation of PNECs.

Classification and labelling: the lowest short-term effect value (from read-across) is in the range of 10 to 100 mg/L. Together with a long-term effect value of >1 mg/L and a log Kow of >4, the substance needs to be classified as Aquatic Chronic 3 (H412: Harmful to aquatic life with long lasting effects), according to regulation EC/1272/2008 (CLP) and its updates.

PBT assessment: solely based on the available aquatic toxicity values, the substance is ‘not T’.

Data matrix for read across

Common names	Orange Flower Ether	Terpineol-multi
Chemical name	4-(1-methoxy-1-methylethyl)-1-methylcyclohexene	2-(4-methylcyclohex-3-en-1-yl)propan-2-ol
Chemical structures
CAS no	14576-08-0	8000-41-7
EC no and registration information	238-620-0, to be registered in 2018	232-268-1; registered in 2010
Empirical formula	C11H20O	C10H18O
Molecular weight	168.28	154.25
Physico-chemical properties
Physical state	liquid	Liquid
Melting point,^oC	-20	-20
Boiling point,^oC	222.2	218.9
Vapour pressure, Pa	9.91      (at 23 °C)	300* A value of 6.48 (at 23 °C) is available from Terpineol-alpha
Water solubility, mg/L	85          (at 23 °C)	2870     (at 23 °C)
Log Kow	4.5^	2.6
Aquatic toxicity
Fish	Read across	96-h LC50 = 62 - 80 mg/L
Aquatic invertebrates	48-h EC50 = 15 mg/L	48-h EC50 = 73 mg/L
Aquatic algae	72-h ErC50 = 26 mg/L 72-h ErC10 = 12 mg/L 72-h NOErC = 4.3 mg/L	72-h ErC50 = 68 mg/L 72-h ErC10 = not determined 72-h NOErC = 3.9 mg/L

*The 300 Pa is considered to be too high and probably due to a volatile impurity. Alpha Terpineol has a vapour pressure of 6.48 Pa, which is more in line with the Vapour pressures of this type of substance and similar to the generally well predicted values of EpiSuite. MPVPBP model predicts 2.6 Pa.

^The measured log Kow is considered conservative because predicted values with EpiSuite and Sparc present a 0.5 lower log Kow value. This is supported with the Koc value of 700 which would be equivalent to a log Kow of 3.65. Also the aquatic toxicity data on Daphnia and algae support a smaller difference in log Kow (ca a 0.5 log unit difference) between the Orange Flower Ether and Terpineol-multi