3-methyl-4-phenylbutan-2-ol

Endpoint summary

Description of key information

In the table the derived acute aquatic toxicity of Muguesia is presented, which is derived from the experimental results of Pamplefleur. The reliability is because of the read across that is applied, the experimental information from Pamplefleur receive Rel. 1.

Species	Guideline	Result in mg/l	Remarks
Pseudokirchneriella subcapitata	OECD TG 201	ErC50 72h = 20 ErC10 72h = 11	Key study, Reliability K2. Result based on read across substance, recalculation based on MW ratio was not performed as changes would be minor and not critical.
Daphnia magna	OECD TG 202	EC50 48h = 8.7	Key study, Reliability K2. Result based on read across substance, recalculation based on MW ratio was not performed as changes would be minor and not critical.

The read across justification is presented below

Muguesia and its aquatic toxicity for algae and Daphnia using read across information fromPamplefleur

Introduction and hypothesis for the analogue approach

Muguesia consists of an aromatic ring to which a butyl chain is attached, with a methyl group on the second spot and a (secondary) alcohol on the third spot. For this substance no aquatic toxicity information is available.In accordance with Article 13 of REACH,lacking information can be generated by means of applying alternative methods such asin vitrotests, QSARs, grouping and read-across. For assessing the aquatic toxicity of Muguesia the analogue approach is selected because for a closely related analogue reliableaquatic toxicitydata are available.

Hypothesis: Muguesia has the same aquatic toxicity as Pamplefleur because both substances are very similar in structure.

Available experimental information: Pamplefleur is tested inwell performed short term aquatic toxicity test according to OECD TG 201 and 202 in a static test set up design, with a Klimisch 1 which resulted in an ErC50 and EC10 value of 20 and 11 mg/l , respectively, for algae. For Daphnia the EC50 value of 8.7 mg/L was found.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical are shown in the data matrix. Also physico-chemical properties thought relevant for aquatic toxicity are listed in there.

Purity / Impurities

The purity and impurities of the target chemical do not indicate other aquatic toxic potential and/or the acute/chronic ratio. The impurities are all below < 10%.

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. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation.

In accordance with ECHA guidance 2017 Pamplefleur was selected for read across because the substance is very similar in structure and for this substance aquatic toxicity information is available.

Structural similarities and differences:The target and the source chemicals both have a phenyl-butyl backbone and an alcohol functional group. The differences are that an additional methyl is present on the butyl chain of Pamplefleur, and while Muguesia is a secondary alcohol,Pamplefleur is a primary alcohol. Overall,Pamplefleur has one more carbon than Muguesia, resulting in a slightly higher molecular weight and hence log Kow.

Bioavailability:The source chemical and the target chemical have similar bioavailability based on the similarity in chemical structure and physico-chemical properties. The molecular weight of the target substance (Muguesia) is 164.25, whereas for the source (Pamplefleur) it is 178.75. They are both liquids. They have similar vapour pressures, 1.1 and 0.3 Pa. The water solubility of Muguesia (3300 mg/L) is somewhat higher possibly due to the one methyl group less. This, however did not result in a lower log Kow (3.1) compared to Pamplefleur (log Kow is 3.0). The calculated log Kows did show a higher log Kow for Pamplefleur (ECOSAR) as expected.

Mode of Action and the prediction of the aquatic toxicity information:Muguesia andPamplefleurhave the same Neutral organic Mode of Action (OECD Toolbox and Verhaar rules).

Uncertainty of the prediction: There is no remaining uncertainty in view of the reasoning above. It is not thought necessary to convert the values of Pamplefleur towards Muguesia in view of the minor differences in both molecular weight and log Kow.

In the ECHA guidance (2017, RAAF) terminology it receives a score of 5 (acceptable with high confidence), because the rationale for the selection of the analogues is clearly documented.

Data matrix

The relevant information on physico-chemical properties and ecotoxicological characteristics for the source and target substances are presented in the data matrix below.

Conclusions on this endpoint

When using read across the result derived should be applicable for C&L and/or risk assessment and be presented with adequate and reliable documentation.

The aquatic toxicity information for Muguesia is derived from the analogue Pamplefleur based on similarity in structural similarity, bioavailability and Mode of Action: both are neutral organics.

For Pamplefleur, the ErC50 and EC50 for algae and Daphnia are 20 and 8.7 mg/l, respectively. The long-term ErC10 for algae is 11 mg/l. These values are directly used for read across to Muguesia.

Final conclusion on hazard for Muguesia: The acute algae ErC50 and EC50 for Daphnia are 11 and 8.7 mg/l, respectively: The long term Algae ErC10 is 11 mg/l.

 

Data matrix of Muguesia aquatic toxicity using read across from Pamplefleur

Common names	Muguesia	Pamplefleur
Chemical structures
Cas no	56836-93-2	92585-24-5
Physico-chemical data
Molecular weight	164.25	178.75
Physical state	Liquid	Liquid
Melting point °C	<-20 (IFF, 2015)	27.62 (EPIWIN prediction)
Boiling point °C	245.5 (IFF, 2015)	273.72 (EPIWIN prediction)
Vapour pressure Pa (measured)	1.1 (IFF, 2015)	0.303 (IFF, 1988)
Water solubility mg/l (measured)	3300 (IFF, 2015)	801 (IFF, 1988)
Log Kow (measured)	3.1 (IFF, 2015)	3.01 (IFF, 1988)
Log Kow (calculated - ECOSAR)	2.89	3.384
Acute Aquatic toxicity
Fish mg/l	No experimental data	LC50: 13 mg/l, (IFF, 1987)
Daphnia mg/l	RA to Pamplefleur	EC50, 48h: 8.7 mg/l, (IFF, 1988)
Algae mg/l	RA to Pamplefleur	EC50, 72h: 20 mg/L (IFF, 2012)
Long-term Aquatic toxicity
Algae mg/l	Read across to Pamplefleur	ErC10: 11 mg/L