Fatty acids, C16-18 (even numbered), reaction products with tetraethylenepentamine, acetates (salts)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have similar toxicological and ecotoxicological properties because
• they are manufactured from similar precursors under similar conditions
• they share structural similarities and common functional groups
• the analytical descriptors show comparable results
• the metabolism pathway leads to comparable products (amine backbone and long chain fatty acids) and non-common products predicted to have no toxicological effects (long chain fatty acids).

This read-across hypothesis corresponds to scenario 2 - different compounds have qualitatively and quantitatively the same type of effects - of the read-across assessment framework i.e. properties of the target substance C1618FA-TEPA-compound are predicted to be similar to those of the source substances Partially unsaturated IQAC, DMS quaternised and oleic acid based IQAC, DMS quaternised.

Based on the available experimental data, the read-across strategy is supported by close structural analogy as well as similar toxicological profiles.

Therefore, read-across from the existing sub-chronic toxicity studies and pre-natal developmental toxicity as well as ecotoxicological studies on the source substance is considered as an appropriate adaptation to the standard information requirements of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Please refer to detailed Justification for read-across attached to Iuclid section 13

3. ANALOGUE APPROACH JUSTIFICATION
Please refer to detailed Justification for read-across attached to Iuclid section 13

4. DATA MATRIX
Please refer to detailed Justification for read-across attached to Iuclid section 13

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Key result

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

100 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

2.1 mg/L

95% CI:

>= 1.7 - <= 2.5

Nominal / measured:

nominal

Conc. based on:

other: water accommodated fractions (WAFs)

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.8 mg/L

95% CI:

>= 4.3 - <= 5.5

Nominal / measured:

nominal

Conc. based on:

other: water accommodated fractions (WAFs)

Basis for effect:

growth rate

Description of key information

The 72-hour LOEC for the growth rate was determined to be 1.0 mg/L (corresponding to a mean measured concentration of 21 μg/L) and the 72-hour NOEC for the growth rate was determined to be 0.32 mg/L (corresponding to a mean measured concentration of 7.6 μg/L) based on water accommodated fractions (WAFs).
In addition a long-term Coupled OECD Confirmatory test (5 weeks) for algae under flow through conditions for the closely related partially unsaturated IQAC, DMS quaternised is available. During the 35d exposure there was no change observed in the measured density of the algae cultures exposed to the test substance doted activated sludge unit. The 35d NOEC was determined to be > 100 μg/L, which is well in tune with the 72 h NOEC of the solvent-free oleic-acid based IQAC, DME quaternised. The Coupled OECD Confirmatory test is considered to be the better model for field conditions in surface waters at the outlet of sewage treatment plants and provide a more realistic scenario of exposure of algae.

Key value for chemical safety assessment

EC50 for freshwater algae:

4.8 mg/L

EC10 or NOEC for freshwater algae:

100 µg/L

Additional information

Experimental data on toxicity to aquatic algae and cyanobacteria of C16 18FA-TEPA-compoundare not available. However, toxicity studies in algae were conducted with the structurally related source substance Partially unsaturated IQAC, DMS quaternised. A justification for read-across is attached to Iuclid section 13.

In a 72 hour toxicity test Pseudokirchneriella subcapitata were exposed to the closely related substance partially unsaturated IQAC, DMS quaternised under static conditions in accordance to OECD Guideline 201 (2006). The 72-hour LOEC for the growth rate was determined to be 1.0 mg/L (corresponding to a mean measured concentration of 21 μg/L), the 72-hour NOEC for the growth rate was determined to be 0.32 mg/L (corresponding to a mean measured concentration of 7.6 μg/L) and the 72 -hour ErC50 was determined to be 4.8 mg/L (56 μg/L measured) 95% C.I.: 4.3 to 5.5 mg/L (52 to 61 μg/L measured) based on water accommodated fractions (WAFs). The 72-hour LOEC for yield was determined to be 0.10 mg/L (corresponding to a mean measured concentration of 2.8 μg/L) and the 72- hour NOEC for yield was determined to be 0.032 mg/L (corresponding to a mean measured concentration of 0.52 μg/L) based on water accommodated fractions (WAFs).
The measured concentrations in the test media of the two lowest test item treatments with loading rates of 0.010 and 0.032 mg/L were <LOQbio (limit of quantification, 0.614 μg/L). The measured concentrations at the loading rates of 0.10, 0.32, 1.0, 3.2, 10 mg/L were 2.2, 6.2, 11, 14 and 22 μg/L, respectively. The biological results were related to the loading rates of the test item and to mean measured test item concentrations. There were no compound related phytotoxic effects.

 

In a 5 weeks long-term toxicity study in a Coupled OECD Confirmatory Test the cultures of Scenedesmus subspicatus CHODAT (new name: Desmodesmus subspicatus) were exposed to the degradation products of the closely related partially unsaturated IQAC, DMS quaternised of an activated sludge unit at 24 °C. There was no change in the measured extinction of the algae cultures exposed to the surfactant doted activated sludge unit during the test period of 5 weeks. Only minor variation was observed. The mean extinction was 0.75 E. Visual inspection of the alga cultures showed optimal green coloured cultures, an indication of high active chlorophyll. Sedimentation of algae was not observed. The culture remained stabile over 5 weeks and no negative effects were observed. In comparison the control culture was somewhat labile, so that it could be concluded that the algae culture exposed to the degradation products was slightly promoted. During the test partially unsaturated IQAC, DMS quaternised, is eliminated in the model activated sludge unit by > 90%. The elimination is calculated to be 97.75% taking into account the inflow into the model activated sludge unit of the test substance with a concentration of 10 mg/L, the dilution of the effluent of the elimination unit in ratio 1:1.25 and the separately determined EC0=0.1 mg/L. Thus a NOEC of >100 μg/L is calculated.