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Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

toxicity to aquatic algae and cyanobacteria
Type of information:
Adequacy of study:
key study
Study period:
October 2013
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Estimation performed by method recommended by REACH Guidance - Guidance on information requirements and chemical safety assessment, Chapter R7b: Endpoint specific guidance (May 2008, v1.1).
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Reference Type:
other: (Q)SAR
Report date:

Materials and methods

Test guideline
no guideline followed
Principles of method if other than guideline:
The structure-activity relationships (SARs) presented in ECOSAR are used to predict the aquatic toxicity of chemicals based on their similarity of structure to chemicals for which the aquatic toxicity has been previously measured.  Most SAR calculations in the ECOSAR Class Program are based upon the octanol/water partition coefficient (Kow). Further details on the methodology, accuracy and applicability domain are avilable in the QSAR Model Reporting Format available in the section entiled : "overall attachment and remarks".

Test material

Constituent 1
Chemical structure
Reference substance name:
2-(2-hydroxyethoxy)ethyl 2-hydroxypropyl 3,4,5,6-tetrabromophthalate
EC Number:
EC Name:
2-(2-hydroxyethoxy)ethyl 2-hydroxypropyl 3,4,5,6-tetrabromophthalate
Cas Number:
Molecular formula:
C15H15Br4O7 (one ring component) C8 H2 Br4 O4 . C4 H10 O3 . C3 H8 O2 Unspecified reaction product of the three components
2-(2-hydroxyethoxy)ethyl 2-hydroxypropyl 3,4,5,6-tetrabromophthalate
Test material form:
other: SMILE notation
Details on test material:
- SMILE notation: CC(O)COC(=O)c1c(Br)c(Br)c(Br)c(Br)c1C(=O)OCCOCCO

Sampling and analysis

Analytical monitoring:

Test solutions


Test organisms

Test organisms (species):
other: freshwater alga

Study design

Test type:
other: Refer to the attached document
Water media type:
Limit test:

Test conditions

Reference substance (positive control):
not required

Results and discussion

Effect concentrationsopen allclose all
96 h
Dose descriptor:
Effect conc.:
4.391 mg/L
Nominal / measured:
Conc. based on:
other: ESTERS (ECOSAR Class)
Basis for effect:
other: modeled
96 h
Dose descriptor:
Effect conc.:
9.052 mg/L
Nominal / measured:
Conc. based on:
other: Neutral Organic SAR (ECOSAR class)
Basis for effect:
other: modeled
Details on results:
According to the estimated toxicity value for long-term toxicity on fish, the chemical may not be soluble enough to measure this predicted effect.
Reported statistics and error estimates:
Applicability domain:
In the development of the ECOSAR equations for neutral organics and classes with excess toxicity, the training sets generally include chemicals with log Kow values in the range of -3 to 8 and molecular weights less than 1000. The structure tested falls into these recommandations.

Any other information on results incl. tables

The registered substance (CAS # 20566-35-2) involves the heating and subsequent reaction of Tetrabromophthalic Anhydride (TBPA) with Di-Ethylene Glycol (DEG) and Propylene Oxide (PO). The nature of the reagents involves the formation of a complex mixture of products with different combinations of these 3 reagents. Current, QSAR models cannot test UVCB substances. Therefore, the QSAR has been performed on the major product which is also the structure with the lowest molecular weight (1 unit of region of TBPA, 1 DEG and 1 PO). In terms of predicted toxicology, it can reasonably be assumed that the structure having the lowest molecular weight should be the most bioavailable. Based on this toxicity principle, QSAR analyses were performed using the SMILE structure of the smallest molecular weight structure which is also the major product of the mixture (identified at 26% area by HPLC).

In addition, same model has been ran with SMILE notation of 1 unit of TBPA, 1 DEG and with 2 or 3 PO (See below SMILE notation and parameters) and same order of magnitude was found for these 2 moldecules presenting 1 unit of TBPA. In contrast, when looking at the results for 2 units of TBPA, values are dramatically decreasing but parameters are outside of the model boundaries limits.

*Smile notation for 1 unit of TBPA, 1 DEG and 2 PO:



Mol For: C18 H22 Br4 O8

Mol Wt: 685.99

Log Kow (KOWWIN v1.68): 3.97

*Smile notation for 1 unit of TBPA, 1 DEG and 3 PO:



Mol For: C21 H28 Br4 O9

Mol Wt: 744.07

Log Kow (KOWWIN v1.68): 4.11

Applicant's summary and conclusion

Validity criteria fulfilled:
Toxicity to green algae using the ECOSAR v1.00, predicted a EC50 (96h) of 4.391 mg/L when the toxicity is based on the ester class according the SMILE structure of the lowest molecular weight in the UVCB substance and a EC50 (96h) of 9.052 mg/L when is based on the neutral organic SAR class. In addition, and based on the predicted water solubility, the estimated toxicity values are above the solubility limit.