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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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:
Please see Analogue Approach
Reason / purpose:
read-across source
Analytical monitoring:
yes
Key result
Duration:
72 h
Dose descriptor:
EL10
Effect conc.:
> 100 other: % satured solution
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
loading rate
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EL50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
loading rate WAF
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
>= 100 other: % saturated solution
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
loading rate
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
> 50 other: % saturated solution
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
loading rate
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EL50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
loading rate WAF
Basis for effect:
other: yield inhibition
Conclusions:
In this study static algae test according to OECD-guideline 201 1,2,3-Propanetricarboxylic acid, 2-Hydroxy-, tris(C12-C13-branched-alkyl)ester was found to slightly inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours. The NOEC-values for inhibition of both growth rate and yield after 72 hours were 50.0 % of the saturated solution. The EC50-values for inhibition of both growth rate (ErC50) and yield (EyC50) after 72 hours were > 100 % of the saturated solution (100 mg/L nominal loading rate WAF).

The growth rate inhibition at 100 % saturated solution was found to be statistical significant at 3 % inhibition compared to control. Due to this low inhibitory effect (< 10 %, biological significance) it may be justified to assume this effect as unspecific.

No further effects are expected at higher concentrations of nominal 100 mg/L due to the calculated water solubility of ≤ 0.739 ng/L.



Executive summary:

The toxicity of 1,2,3-Propanetricarboxylic acid, 2-Hydroxy-, tris(C12-C13-branched-alkyl)ester to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No. 761/2009 Method C.3. The aim of the study was the determination of NOEC, LOEC, EC10- , EC20- and EC50-values of growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 6153 cells/mL. A saturated solution of 100 mg/L was prepared with dilution water and stirred for 48 hours. Then undissolved particles were removed by membrane filtration (membrane filter 0.2 µm, RC, MACHEREY-NAGEL). Five concentrations were tested in a geometrical series with a dilution factor of 2: 6.25 - 12.5 - 2.50 - 50.0 - 100 %. Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditions were within the acceptable limits. The test media were clear throughout the test period. The concentrations of the test item 1,2,3 -Propanetricarboxylic acid, 2 -Hydroxy-, tris(C12 -C13 -branched-alkyl)ester in all test concentrations and the control were analytically verified by LC-MS/MS at the start and the end of exposure. The saturated solution with a nominal concentration of 100 mg/L was diluted to prepare different concentrations. To account for the low calculated water solubility of the substance, all effect values given are based on nominal test item concentrations.

Only slight effects of the test item 1,2,3-Propanetricarboxylic acid, 2-Hydroxy-, tris(C12-C13-branched-alkyl)ester on the green alga Pseudokirchneriella subcapitata in terms of inhibition of growth or yield was found up to the 100 % saturated solution. The growth rate inhibition at 100 % saturated solution was found to be statistical significant at 3 % inhibition compared to control. Due to this low inhibitory effect (10 %, biological significance) it may be justified to assume this effect as unspecific. No further effects are expected at higher concentrations of nominal 100 mg/L, due to the calculated water solubility of ≤ 0.739 ng/L.

Description of key information

In an algae test according to OECD-guideline 201 with the similar substance 1,2,3 -Propanetricarboxylic acid, 2 -Hydroxy-, tris(C12 -C13 -branched-alkyl)ester the test substance was found to slightly inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours. The NOEC-values for inhibition of both growth rate and yield after 72 hours were 50.0 % of the saturated solution. The EC50 -values for inhibition of both growth rate (ErC50) and yield (EyC50) after 72 hours were > 100 % of the saturated solution (100 mg/L nominal loading rate WAF). Also the source substance Tri (hexyl, octyl, decyl) citrate was not toxic up to the limit of water solubility.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L

Additional information

The toxicity of the similar substance 1,2,3-Propanetricarboxylic acid, 2-Hydroxy-, tris(C12-C13-branched-alkyl)ester to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD 201 and Council Regulation (EC) No. 761/2009 Method C.3. The aim of the study was the determination of NOEC, LOEC, EC10- , EC20- and EC50-values of growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 6153 cells/mL. A saturated solution of 100 mg/L was prepared with dilution water and stirred for 48 hours. Then undissolved particles were removed by membrane filtration (membrane filter 0.2 µm, RC, MACHEREY-NAGEL). Five concentrations were tested in a geometrical series with a dilution factor of 2: 6.25 - 12.5 - 2.50 - 50.0 - 100 %. Three replicates were tested for each test item concentration and six replicates for the control. The environmental conditions were within the acceptable limits. The test media were clear throughout the test period. The concentrations of the test item 1,2,3 -Propanetricarboxylic acid, 2 -Hydroxy-, tris(C12 -C13 -branched-alkyl)ester in all test concentrations and the control were analytically verified by LC-MS/MS at the start and the end of exposure. To account for the low calculated water solubility of the substance, all effect values given are based on nominal test item concentrations.

The influence of the source substance 1, Tri (hexyl, octyl, decyl) citrate, on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72 -hour static test according to the OECD Guideline No. 201, adopted June 7, 1984. The test was performed in compliance with GLP. Due to the low water solubility of the test substance a filtrate of a supersaturated stock suspension of nominal 100 mg/L was tested. Thus, no concentrations above the solubility limit of the test substance in the used test water were tested. Also due to the low water solubility no analytical verification could be done in the present test. Therefore, the biological results could not be related to a specific concentration of the test substance but only to the water solubility limit in the test medium.

The 72-hour NOEC was determined to be at least up to the solubility limit of the test substance. The NOEC might even be higher than this concentration, but concentrations in excess of the solubility limit had not been tested. The 72-hour LOEC and the 72-hour EC50 were clearly higher than the solubility limit.

It is expected that the same is valid for the substance 1,2,3-Propanetricarboxylic acid, 2-hydroxy-, tri-C14-15-alkyl esters.