4-(2-hydroxyethyl)-1-piperazinepropanesulphonic acid

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:

ANALOGUE APPROACH JUSTIFICATION
Please refer to the attached read-across justification in section 13

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Description of key information

In an experimental study under GLP conditions according to OECD Test Guideline 201 using the algae Pseudokirchneriella subcapitata, the 72 h algal growth inhibition EC₅₀ of the read-across source substance was determined as > 100 mg/L based on growth rate and yield. The overall NOEC of the source substance was determined to be ≥ 100 mg/L (reference 6.1.5-1).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

No experimental data with the test item is available. Therefore, a read-across approach with a read-across source substance with a very similar chemical structure and comparable physicochemical properties is used to evaluate the toxicity potential of the test item to algae.

 

The effect of the read-across source substance was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata (Selenastrum capricornutum), over an exposure period of 72 hours in a closed static test system according to OECD 201 (2006) under GLP conditions. Based on the results of a preliminary test, the test item has no toxic effect on algae up to 100 mg/L (limit concentration). Therefore the main test was performed at 100 mg/L including a concurrent control. The measured concentration were determined to be 95.5, 97.6, 96.9, 100.9, 101.5 and 100.4 mg/L. The measured test item concentration remained within ± 20 % of the nominal over the test period of 72 hours, therefore the biological results are based on the nominal concentration. Exponentially-growing cultures of Pseudokirchneriella subcapitata were exposed to the test item over several generations under defined conditions (static test). The algal growth in relation to a control culture was determined over a fixed test period of 72 hours and, thus, over several algal generations. The test design included six replicates per test concentration and control. The algal cell concentration was approximately 10000 cells/mL at the start of the test in all of the test cultures. Glass flasks with total capacity of 250 mL were used as test vessels. The volume of the test liquid in the vessels was 100 mL. The algae cell concentration was determined by microscope in each testing flask during the 72 hour test, in 24 hour intervals. In the test no morphological effects were observed in the 100 mg/L test item concentration. For the evaluation of the reliability of the applied test system and the experimental conditions potassium dichromate is tested at least twice a year. The 72 h ErC₅₀ of the reference substance was determined to be 1.36 mg/L. The validity criteria of the test was met. Statistical comparisons of average specific growth rates and yield in control and in treated groups were carried out using 2 Sample t-Test (a = 0.05, TOXSTAT software). The results of the statistical evaluation showed that the 0 - 72 h average specific growth rate and yield in the treatment group (100 mg/L) was not statistically significantly different from the untreated concurrent control. The No Observed Effect Concentration (NOEC) was determined to be 100 mg/L (limit concentration). As the test item had no significant effect on the growth of algae therefore statistical analysis was not performed to determine the EC values. The 72 h EC₅₀ values based on growth rate and yield were determined to be > 100 mg/L. These results are also applied for the read-across to the target substance.