(R)-thiazolidine-4-carboxylic acid

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

(R)-thiazolidine-4-carboxylic acid

EC Number:

252-106-3

EC Name:

(R)-thiazolidine-4-carboxylic acid

Cas Number:

34592-47-7

Molecular formula:

C4H7NO2S

IUPAC Name:

(R)-thiazolidine-4-carboxylic acid

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Batch number 20190104
Expiry date January 01, 2021
Purity 99.3 % w/w

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

The test concentrations were chosen in accordance with the results of a non-GLP pre-test
(range-finding test).
The test was performed at five test item concentrations in a geometric series calculated with a
factor 2.2, namely 4.3, 9.4, 20.7, 45.5 and 100.0 mg test item/L.
At the test start, a 100.0 mg test item/L stock solution was prepared by direct weighting 0.0500
g of test item into 500 mL of algal growth medium.

Test organisms

Test organisms (species):

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

Details on test organisms:

The algae were cultured in a climatic chamber at 24 ± 2°C under continuous uniform
illumination in the range 4440 - 8880 Lux in the spectral range 400-700 nm. The culture
medium was the same of the test medium; the stock cultures were transferred weekly to fresh
medium and maintained in continuous shaking to ensure the necessary amount of CO2 and to
keep algae in suspension. Cultures containing deformed or abnormal cells were discarded.
Only exponentially growing algal cultures were used to start the test.

Study design

Water media type:

freshwater

Total exposure duration:

72 h

Post exposure observation period:

Algal cell density was measured every 24 hours by taking aliquots from each test concentration
replicate and the negative control, diluting them in a NaCl 9 g/L solution and reading with an
electronic particle counter.

The measured values were used to calculate the percentage inhibition of cell growth as yield
and as growth rate in comparison to the solvent control.

Test conditions

Test temperature:

23.46 – 24.68°C.

pH:

pH was measured at the start and at the end of the test, in the negative control and in test item solutions.
At the end of the test the pH value of negative control replicates was between 7.51 and 7.90
(mean value 7.77) and it varied by a maximum of 0.55 units over the course of the test

Nominal and measured concentrations:

negative control (algal medium without test item)
4.3, 9.4, 20.7, 45.5 and 100.0 mg test item/L;.
Test concentrations were chosen based on the results of an acute toxicity no GLP test .

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

69.1 mg/L

95% CI:

59.3 - 76.2

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

20.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

45.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

In fresh solutions, prepared at time 0, the analytical recoveries of L(-)-Thiazolidine-4-carboxylic acid (TCA) were between 103.7 – 109.8 % of the nominal values.
After 72 hours, the analytical recoveries of L(-)-Thiazolidine-4-carboxylic acid (TCA) were
between 106.0 – 110.7 % of the nominal values. Since all analytical recoveries were in the range 80 % - 120 % of the nominal concentrations, the biological results were referred to the test item nominal concentrations.
No remarkable observations were made concerning the appearance of the cells of the
inoculum culture and of the test item treated algae.

At the end of the test, growth rate inhibition ranged from 0.9% (at 20.7 mg/L test item
concentration) to 17.2% (at 100.0 mg/L test item concentration), at 4.3 mg/L and 9.4 mg/L test
item concentration no inhibition was found, compared to the negative control.
At the end of the test, yield inhibition ranged from 5.1 % (at 20.7 mg/L test item concentration)
to 65.9 % (at 100.0 mg/L test item concentration), at 4.3 mg/L and 9.4 mg/L test item
concentration no inhibition was found, compared to the negative control.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of test item L(-)-Thiazolidine-4-carboxylic acid (TCA) was tested on green algae Pseudokirchneriella subcapitata.
The 72-hour EC10, EC20 and EC50, the NOEC and LOEC, calculated in terms of nominal test
item concentrations, for the two end-points, are:
EC50 Growth rate 72h > 100 mg/l
EC50 Yield 72h= 69.1 mg/l
NOEC 72h =20.7 mg/l
LOEC 72h =45.5 mg/l