Amides, adipic acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 May 2019 to 28 June 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Remarks:

GLP Provisional Certificate

Analytical monitoring:

yes

Remarks:

Determination of Total Organic Carbon (TOC) has been done using an automatic SHIMADZU TOC analyser.

Vehicle:

yes

Details on test solutions:

Algal suspension from stock culture has been inoculated in the receivers containing the defined concentration of the test sample.
Erlenmeyer flasks containing treated organisms and Erlenmeyer flasks containing control organisms, have been kept in suspension by steady stirring at 23°C + 2°C under continuous light for 72 + 2 h.

Test organisms (species):

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

Details on test organisms:

Test organism: Green alga
Genus: Pseudokirchneriella
Species: subcapitata
Family: Chlorophyceae
Order: Chlorococcalles

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Remarks on exposure duration:

Organisms have been kept in suspension by steady stirring at 23°C ± 2°C under continuous light

Post exposure observation period:

The test and control samples were incubated for a period of 72 h during which the cell density in each test and control solution was measured every 24 h by Burker chamber. pH has been measured at the beginning and at the end of the assay. Temperature of the ambient has been recorded every 24 hours.
At the end of the test the quality of algae appearance has been observed at microscopy.

Hardness:

Not specified

Test temperature:

23°C ± 2°C

Dissolved oxygen:

Not specified

Salinity:

Not specified

Conductivity:

Not specified

Nominal and measured concentrations:

Range-finding test:
Nominal: A solution at 1000 mg/L of the test item has been prepared in culture medium. Then 5 different concentrations have been prepared with ten-fold dilutions from 1000 mg/L to 0.1 mg/L. The test has been performed on the diluted solutions.
Limit test:
Nominal: After the range finding test a solution at 100 mg/L of the test item has been prepared in culture medium

Details on test conditions:

Starting cellular density - 10E+4 cell/mL
No. of replications - 6 for control and 3 for all treated concentrations in range finding and 6 for control and 6 for all treated concentrations definitive test (limit test)
Concentrations - 5 for range finding test and 1 for definitive test (limit test)
Lightning - Continuous — with fluorescent lamp (7000- 8000 lux)
Stirring - Steady with electrical stirrer
Temperature - 23°C ± 2°C
Assay duration - 72 ± 2 h

Reference substance (positive control):

not specified

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 72 h EC50 of the test substance to aquatic algae, based on growth rate, was determined to be >100 mg/L (nominal).

Executive summary:

A study was conducted to determine the acute toxicity of the test substance to the green algae Pseudokirchneriella subcapitata according to OECD 201 Guideline, in compliance with GLP. During the range finding test, the algae were exposed to 5 different dilutions of the test substance for 72 h. After the results of the range finding test, a definitive limit test was performed. The results from preliminary test served as the basis to select the test concentrations in the main experiment (limit test). Controls were added to demonstrate the adequacy of the procedure. Test concentrations were analytically determined at the start and end of the experiment. The test design included 3 replicates at each test concentration in the dose range finding test and 6 replicates for the untreated controls and treatment concentration in the definitive limit test. The algae were exposed to 100 mg/L of the test substance for 72 h. At the end of the test, microscopic observation was performed to verify a normal and healthy appearance of the algal culture and to observe any abnormal appearance of the algae. The validity criteria of the definitive was found to be fulfilled. Under the study conditions, the 72 h EC50 of the test substance to aquatic algae, based on growth rate, was determined to be >100 mg/L (nominal) (Giarei, 2019).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

Additional information

A study was conducted to determine the acute toxicity of the test substance to the green algae Pseudokirchneriella subcapitata according to OECD 201 Guideline, in compliance with GLP. During the range finding test, the algae were exposed to 5 different dilutions of the test substance for 72 h. After the results of the range finding test, a definitive limit test was performed. The results from preliminary test served as the basis to select the test concentrations in the main experiment (limit test). Controls were added to demonstrate the adequacy of the procedure. Test concentrations were analytically determined at the start and end of the experiment. The test design included 3 replicates at each test concentration in the dose range finding test and 6 replicates for the untreated controls and treatment concentration in the definitive limit test. The algae were exposed to 100 mg/L of the test substance for 72 h. At the end of the test, microscopic observation was performed to verify a normal and healthy appearance of the algal culture and to observe any abnormal appearance of the algae. The validity criteria of the definitive was found to be fulfilled. Under the study conditions, the 72 h EC50 of the test substance to aquatic algae, based on growth rate, was determined to be >100 mg/L (nominal) (Giarei, 2019).